Bizzarri, F.a , Brambilla, A.a , Ferrara, V.b , Gruosso, G.a , Storti-Gajani, G.a , Vigano, L.c
Efficiency improvement of partially shaded photovoltaic panels
(2013) 2013 European Conference on Circuit Theory and Design, ECCTD 2013 – Proceedings, art. no. 6662254, .
http://www.scopus.com/inward/record.url?eid=2-s2.0-84892632829&partnerID=40&md5=ce7a32db02eaf845e1fe3882019b158c
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, p.za. Leonardo da Vinci, n. 32, I20133 Milan, Italy;
Pegasus Microdesign, via Gilera 110, Arcore, Italy;
EU Energy, via Salvo D’Acquisto 39, I20059 Concorezzo (MI), Italy
ABSTRACT: Layouts of domestic photovoltaic solar plants can be problematic due to obstacles that shade panels. This limits the total available area and, if not adequately considered, can deeply affect the efficiency of the plant. In this paper, a circuit that recovers generated power efficiency when a small number of cells of a panel are partially or totally shaded is proposed. This circuit is constituted by DC/DC converters that are connected in parallel to cells and that balance power generation. This solution is borrowed by architectures used to balance charge/discharge of lithium ion batteries. Simulation results and experimental measurements performed on a prototype version of the circuit are reported and described together with its advantages and drawbacks. © 2013 TU Dresden.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bozzi, S.a , Miquel, A.M.a , Scarpa, F.a , Antonini, A.b , Archetti, R.b , Passoni, G.a , Gruosso, G.a
Wave energy production in Italian offshore: Preliminary design of a point absorber with tubular linear generator
(2013) 4th International Conference on Clean Electrical Power: Renewable Energy Resources Impact, ICCEP 2013, art. no. 6586990, pp. 203-208.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84884624219&partnerID=40&md5=33e13ef3e3ad6a9b90c7cdb8893dea8c
AFFILIATIONS: Department of Electronics, Information Science, and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy;
Department of Civil, Environmental and Materials Engineering, University of Bologna, Viale Risorgimento 2, 40136, Bologna, Italy
ABSTRACT: The paper presents the preliminary design and modelling of a point absorber wave energy converter consisting of a floating buoy connected to a tubular linear generator fixed at the seabed. The behaviour of the device is described by the equation of motion of a single body system restricted to vertical motion. The model of the coupled buoy-generator system is used to simulate the behaviour of the wave energy converter under regular waves of different heights and periods. Then the electricity production of an hypothetical installation off the Alghero coast is estimated. The results show that the device capacity factor at the study site is around 15%. This is a very promising value considering that the studied device has not been specifically optimized for the Alghero wave climate. The work suggests that the presented technology could be very attractive for the Italian offshore. © 2013 IEEE.
AUTHOR KEYWORDS: Italian offshore; linear tubular generator; point absorber; wave energy
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bizzarri, F., Brambilla, A., Gruosso, G., Gajani, G.S.
Time domain probe insertion to find steady state of strongly nonlinear high-Q oscillators
(2013) Proceedings – IEEE International Symposium on Circuits and Systems, art. no. 6572229, pp. 1865-1868.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84883377528&partnerID=40&md5=0f70d04183486b958ea0836d3361b8fd
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, P.za. Leonardo da Vinci, n. 32, I20133 Milan, Italy
ABSTRACT: Probe insertion is traditionally used in the frequency domain to increase robustness of the harmonic balance method and avoid the DC degenerate solution. This technique evidences several good properties, for instance when simulating oscillators that are based on high quality factor resonators or AC coupled ones. In this paper the probe insertion technique is extended to the time domain, allowing the application of the shooting method to a wider class of circuits including for example crystal oscillators. Time domain methods, such as shooting, are superior in the simulation of strongly nonlinear, and, thanks to a recent extention, mixed analog/digital circuits. Moreover, time domain probe insertion can be used to find multiple steady state solutions and check their stability properties, without the need to compute the eigenvalues of the monodromy matrix. © 2013 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bizzarri, F.a , Brambilla, A.a , Gruosso, G.a , Guardiani, C.b , Sangiovanni Vincentelli, A.c , Storti Gajani, G.a
Modeling and estimating yield and efficiency of photovoltaic solar parks
(2013) Proceedings of the IEEE International Conference on Industrial Technology, art. no. 6505763, pp. 734-739. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84877630047&partnerID=40&md5=e438e98448852a3bd789ef27e5ecf6d0
AFFILIATIONS: Politecnico di Milano, DEI, p.za. Leonardo da Vinci, n. 32, I20133 Milano, Italy;
Renience Srl, v.le G. Marconi 52, Desenzano del Garda, Italy;
Dep. of Electrical Engineering and Computer Science, University of California – Berkeley, Berkeley, CA, United States
ABSTRACT: Subsidy reduction and the increased importance of photovoltaic energy generation have triggered the need to develop accurate approaches to measure, estimate and possibly forecast energy production with the goal of enabling early detection and diagnosis of parametric faults before they become catastrophic and lead to partial or full shut down of the plant. Moreover the ability of accurately predicting the energy output of a photovoltaic plant is becoming increasingly important to operate efficiently the existing power grid infrastructure that has difficulties with intermittent, unpredictable power sources. In this paper a new model of photovoltaic solar parks designed to estimate efficiency, predict energy production and enable early fault detection is presented. The proposed model is based on an equivalent electro-thermal model of the PhotoVoltaic (PV) cell, which takes as input the irradiance, ambient temperature and wind speed measured by existing sensors and data-logging equipment used in most solar PV parks. The proposed model is demonstrated to accurately predict the performance of real-life MW scale plants. By directly comparing predicted vs. actual energy production, it also allows easy and early identification and diagnose of malfunctions and efficiency drops of PV systems. © 2013 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bizzarri, F., Brambilla, A., Gruosso, G., Gajani, G.
Probe based shooting method to find stable and unstable limit cycles of strongly nonlinear high-Q oscillators
(2013) IEEE Transactions on Circuits and Systems I: Regular Papers, 60 (7), art. no. 6410373, pp. 1870-1880. Cited 2 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84880052193&partnerID=40&md5=c093d792ee40e8188e810018abeaf0ba
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, I20133 Milano, Italy
ABSTRACT: Probe insertion technique is considered as an exclusively frequency domain approach. It has been developed to increase robustness of the harmonic balance method, when simulating autonomous circuits to avoid the dc degenerate solution. This technique evidences several good properties, for instance when simulating oscillators either employing high quality factor resonators or ac coupled ones. In this paper the probe insertion technique is extended to the time domain. This allows the application of the shooting method to a wider class of circuits including for example crystal oscillators. The inherent superiority of the shooting method to simulate strongly nonlinear circuits and its recent reliable extension to mixed analog/digital ones outperforms the potentiality of the harmonic balance method. Furthermore, this time domain probe insertion technique is exploited to find possible multiple steady state solutions and efficiently check stability properties, thus avoiding to compute the eigenvalues of the monodromy matrix. © 2004-2012 IEEE.
AUTHOR KEYWORDS: Crystal oscillators; multiple steady state solutions; probe technique; shooting method
DOCUMENT TYPE: Article
SOURCE: Scopus

Bizzarri, F., Bongiorno, M., Brambilla, A., Gruosso, G., Gajani, G.S.
Model of photovoltaic power plants for performance analysis and production forecast
(2013) IEEE Transactions on Sustainable Energy, 4 (2), art. no. 6324407, pp. 278-285. Cited 2 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84875689995&partnerID=40&md5=5fdfc52966578aa517371f0a85970223
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e Informazione, I20133 Milano, Italy
ABSTRACT: A photovoltaic (PV) plant model is presented. It is based on a detailed electrothermal description of the panels forming strings that, in turn, form the power plant. It accounts for environmental working conditions, such as temperature and wind speed, and specific plant configuration, such as plant topology and power losses due to interconnections. The input variables of the model are the ambient temperature, irradiance, and wind speed. The model derives the working temperature of the panel taking into account also the power conversion performed by the panel; the electrical operating point is determined by simulating the actions done by the maximum power point tracker that operates at plant level. This model has been tested using a large database of experimental data from industrial PV plants characterized by power levels ranging from 250 kW to 1 MW. As shown, the model is capable to predict power production when ‘fed’ by forecast irradiance, ambient temperature, and wind speed data. © 2010-2012 IEEE.
AUTHOR KEYWORDS: Electrothermal macro-models; maximum power point tracker (MPPT); photovoltaic (PV) power plants; solar panels
DOCUMENT TYPE: Article
SOURCE: Scopus

Pisano, M., Bizzarri, F., Brambilla, A., Gruosso, G., Gajani, G.S.
Micro-inverter for solar power generation
(2012) SPEEDAM 2012 – 21st International Symposium on Power Electronics, Electrical Drives, Automation and Motion, art. no. 6264547, pp. 109-113. Cited 5 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84866923518&partnerID=40&md5=ca1fef5a20b3c32365db28daa0354809
AFFILIATIONS: Politecnico di Milano, DEI, p.za Leonardo da Vinci, 32, I20133 Milano, Italy
ABSTRACT: A micro-inverter that takes as input the DC power generated by a solar panel (about 250W) and delivers it directly as AC power to the mains line is presented. The micro-inverter has been designed with discrete components, as it is common practice, since there are no silicon technologies that can be used to integrate the complete circuit and the passive components. The proposed micro-inverter has been extensively simulated and is currently under realisation. The obtained conversion efficiency is greater than 95% and the total harmonic distortion at the output is less than 0.4%. © 2012 IEEE.
AUTHOR KEYWORDS: circuit simulation; DC/AC converter; hybrid systems; microinverter; shooting method; solar power generation; steady state methods
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bizzarri, F.a , Brambilla, A.a , Gruosso, G.a , Gajani, G.S.a , Ferrando, E.b
ADDA: Almost direct drive architecture for solar high power electrical propulsion in new generation spacecrafts
(2012) ISCAS 2012 – 2012 IEEE International Symposium on Circuits and Systems, art. no. 6271746, pp. 2271-2274. Cited 3 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84866359482&partnerID=40&md5=d914adc8ca2f2c7e53093f8ccf772989
AFFILIATIONS: Politecnico di Milano, DEI, p.za Leonardo da Vinci, 32, 120133, Milano, Italy;
Selex Galileo, viale Europa, 120014, Nerviano, Italy
ABSTRACT: This paper proposes a novel electrical power system architecture capable to efficiently transfer energy from a solar generator to high power electric thrusters of a spacecraft. The architecture is based on a maximum power point tracker that acts on a DC/DC converter connected between a subsection of the solar generator and the thrusters. The other sections of the solar generator, that deliver most of the total power, are directly connected to the thrusters. The novelty of the proposed architecture is that the maximum power point tracker is always operating and, while conditioning only a fraction of the total power, is able to transfer to the thrusters an amount of power greater than the handled one. ©2012 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bizzarri, F.a , Callegarit, S.b , Gruosso, G.a
Towards a nearly optimal synthesis of power bridge commands in the driving of AC motors
(2012) ISCAS 2012 – 2012 IEEE International Symposium on Circuits and Systems, art. no. 6271704, pp. 2119-2122. Cited 3 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84866389256&partnerID=40&md5=868231f7962f9b513cda153fd61a2e2f
AFFILIATIONS: Polytechnic of Milan, DEI, Italy;
University of Bologna, ARCES/DEIS, Italy
ABSTRACT: The synthesis of low depth command streams for power bridges is considered, with regards to drives for ac motors. Focus is on the exploitation of the degrees of freedom still available once the command rate is set. Using a nonlinear motor model, different options are evaluated up to the mechanical output. Options such as Delta Sigma Modulation (δσM) and Pulse Width Modulation (PWM) are associated to tuples of merit factors defining points in a performance space. Standard ASM is shown to favor perceived drive quality, while PWM helps keeping the switching rate low. Interpreting both PWM and δσM as heuristics for Pulse Density Modulation (PDM), it is shown that ASM may offer some commonly unexploited forms of tuning and may lead to a more flexible choice of placement on the performance space. © 2012 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
MTFS: Mixed time-frequency method for the steady-state analysis of almost-periodic nonlinear circuits
(2012) IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 31 (9), art. no. 6269967, pp. 1346-1355.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84865310916&partnerID=40&md5=bdc2fa1f2f1ef7a279b7e4761785eecd
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milan I20122, Italy
ABSTRACT: Periodic circuits driven by multitone signals are still a challenging simulation problem despite several numerical methods being presented in the literature. In this paper, a mixed time-frequency method for the solution of this problem and suitable for both autonomous and nonautonomous circuits is presented. The method is based on an extension of the envelope following method, which allows us to reduce the number of unknowns involved in the steady-state problem with respect to previous mixed time-frequency approaches, and a suitable reformulation of the periodicity constraint that allows us to obtain a significant acceleration in the determination of the solution by reducing the time interval along which the envelope analysis must be performed. The method is first presented for nonautonomous circuits and then extended to autonomous ones. © 2012 IEEE.
AUTHOR KEYWORDS: Envelope analysis; mixed frequency-time domain methods; steady-state analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Mussetta, M.a , Shadmehr, H.a , Grimaccia, F.a , Pirisi, A.a , Gruosso, G.b , Zich, R.E.a
Power transfer optimization of wireless energy harvesting system
(2012) IET Conference Publications, 2012 (592 CP), pp. D64.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84864652086&partnerID=40&md5=a5ce4b2edee0fdb6973ac2a81351a025
AFFILIATIONS: Politecnico di Milano, Dipartimento di Energia, Via La Masa 34, 20156 Milano, Italy;
Politecnico di Milano, Dipartimento di Elettronica e dell’Informazione, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
ABSTRACT: This paper will present a novel approach to the design of wireless energy transfer devices, by means of a recently developed evolutionary optimization method. This approach is well suited in order to increase the transfer efficiency and the robustness of the coupling, with the aim of minimizing the average power loss.
AUTHOR KEYWORDS: Biomedical applications; Energy harvesting; Fractal antenna; Optimization; Wireless power transfer
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Gruosso, G.a , Bizzarri, F.a , Storti Gajani, G.a , Brambilla, A.a , Ferrando, E.b
Design and simulation of a power management unit in a solar based electric propulsion system
(2012) IET Conference Publications, 2012 (592 CP), pp. P240. Cited 4 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84864712251&partnerID=40&md5=0445c4359c196cd7de0733e605f1bb5c
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e Informazione, p.zza L. da Vinci 32, I20133 – Milano, Italy;
SELEX Galileo S.p.A, Via Albert Einstein 35, 50013 Campi Bisenzio (FI), Italy
ABSTRACT: The aim of this paper is to compare different architectures for a power system that supplies electrical thrusters for future space exploration missions. The main goal of these architectures is the maximization of the power extracted from the solar arrays in all operational situations and this is possible only by using peak power tracking algorithms. This limits the choice of architectures only to those including some form of peak power tracking algorithms.
AUTHOR KEYWORDS: Power management; Solar array; Space propulsion
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Pirisi, A.b , Mussetta, M.b , Grimaccia, F.b , Caputo, D.b , Gruosso, G.a , Zich, R.E.b
An innovative device for traffic energy harvesting
(2012) IET Conference Publications, 2012 (592 CP), pp. D53.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84864722801&partnerID=40&md5=69a588ab5a56d1881c54eb45d2ac6443
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e dell’Informazione, Piazza Leonardo da Vinci 32, 20133 Milano, Italy;
Politecnico di Milano, Dipartimento di Energia, Via La Masa 34, 20156 Milano, Italy
ABSTRACT: In recent years the increase of massive connections of renewable systems to power grid has highlighted the need to address stability issues with ad-hoc techniques. On the other side, the complexity of electronic devices requires an integrated approach for the different layers of the system, especially in terms of power quality. This task is often supported by advanced soft computing techniques that can be applied by engineers to several device model and used with optimization process, in order to find out the best design improving the system performance and the industrial electronics applications. This approach promises to give new impulse to research on renewable systems and, especially in the last five years, on the so called Energy Harvesting Devices (EHDs). In this paper an innovative speed bumper for energy harvesting from traffic activities is presented. Energy is converted by means of a suitably designed Tubular Permanent Magnet-Linear Generator (TPM-LiG).
AUTHOR KEYWORDS: Energy harvesting device; Linear generator
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Ferrando, E.a , Croci, L.a , Damonte, G.a , Hazan, D.a , Riva, S.a , Romani, R.a , Casaregola, C.b , Brambilla, A.c , Gruosso, G.c , Gajani, G.S.c , Blott, R.d , Battocchio, L.e , Steiner, M.f , Tuissi, A.g , Casati, R.g , Chiarelli, M.h
Study results on a solar electric power system for High Power Electric Propulsion (HiPER) applications
(2011) 62nd International Astronautical Congress 2011, IAC 2011, 9, pp. 7551-7565. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84864095423&partnerID=40&md5=f58b62dddb3a9f464b69a86a440cf96d
AFFILIATIONS: Selex Galileo, Viale Europa, 20014 Nerviano- MI, Italy;
ALTA S.p.A., Via A. Gherardesca,5, 56121 Pisa, Italy;
Politecnico di Milano, Piazza Leonardo Da Vinci 32, 20133 Milano, Italy;
Space Enterprise Partnerships, Bennetts, Eastergate Lane, Eastergate, Chichester, West Sussex PO20 3SJ, United Kingdom;
AERO SEKUR S.p.A., Via Delle Valli 46, 04011 Aprilia (LT), Italy;
Fraunhofer-Institut für Solare Energiesysteme ISE, Heidenhofstraße 2, 79110 Freiburg, Germany;
Consiglio Nazionale Delle Ricerche, Istituto Per l’Energetica e le Interfasi (CNR-IENI), Corso Promessi Sposi, 29, 23900 LECCO, Italy;
Dipartimento di Ingegneria Aerospaziale, Università di Pisa, Via G. Caruso 8, 56122 Pisa, Italy
ABSTRACT: The aim of this study is, on top of the investigation of an overall PMAD system capable to fulfil the requirements of both solar and nuclear energy sources, to define a solar based power system able to feed high power electric thrusters. This kind of propulsion system could play a very important role in future space exploration programmes by enabling more affordable and sustainable space-to-space missions. HiPER is a project partly funded by the EU aimed at laying the technical and programmatic foundations for the development of technologies to fulfil these future needs. The abstract presents results of development and prototyping of solar generation technologies and gives indications on the optimal PMAD architectures. The power demand of next generation spacecraft will overcome the limits of existing state of the art solar generation systems. Today the multi panel deployable solar array is the most common system utilized for medium and high power applications. Its ability to provide accommodation for power growth up to tens of kW), high reliability, competitive weight and low cost, lead to world wide success but we need something more. Light concentration techniques, thin solar cells and light/flexible substrates are going towards this direction. Starting from our previous experience in lightweight photovoltaic systems, we all initiated the development activities. The main topics addressed in this study are: light concentration (up to 10 times the nominal flux) system design, inflatable substrate and flexible electrical network structural design, prototyping and verification; The solar cell trades started from the very latest achievements in crystalline solar cells. Based on that, a component suitable for light concentration has been identified. This component has been integrated on top of a flexible structure in combination with the concentrating lenses and with an innovative “smart” deployment mechanic based, also, on Shape Memory Alloys (SMA) performances. The PMAD is a critical aspect of the whole system design which can undermine all the other technical advances. A direct drive approach is the most suitable solution and an architecture based on solar DC voltage level of about 300V and a current level of about 800 A has been extensively simulated. Of course there are risks associated with the operation at high current and voltage and this are mainly related to coronal discharge effects. The scope of the present study is to define generic mitigation strategy for making a more precise assessment for the total system mass estimate.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
A probe-based harmonic balance method to simulate coupled oscillators
(2011) IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 30 (7), art. no. 5875987, pp. 960-971.
http://www.scopus.com/inward/record.url?eid=2-s2.0-79959274555&partnerID=40&md5=9ccd93390b0cb0cb1bad6a95ae95bdac
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, Piazza Leonardo da Vinci, Milano I-20133, Italy
ABSTRACT: The probe-based harmonic balance (HB) method is a well-known and largely used tool to compute the steady state behavior of autonomous circuits (oscillators). In this paper, the method is extended to analyze coupled oscillators, where the working frequencies and conditions, i.e., pulling and locking modes, have great relevance. It is shown that probe insertion can be considered as a specific matrix-bordering technique applied to the Jacobian matrix of the HB method. It transforms the original coupled autonomous system in a non-autonomous one, forcing the circuit to lock to the probes themselves. In this context, a novel approach to find the steady state solution is introduced. This approach exploits the properties of the power exchanged among the probes and the coupled oscillators. Possibly, more than one steady state solution with the oscillators working in pulling or locking modes can be found. © 2011 IEEE.
AUTHOR KEYWORDS: Coupled oscillators; harmonic balance; probe insertion method; pulling-locking modes
DOCUMENT TYPE: Article
SOURCE: Scopus

Gruosso, G.a , Mussetta, M.b c , Zich, R.E.b
Optimization of an antenna for wireless energy transfer
(2011) Proceedings of the 5th European Conference on Antennas and Propagation, EUCAP 2011, art. no. 5781720, pp. 1208-1209. Cited 4 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-79959636268&partnerID=40&md5=8a034f9b224fc25bd120606f20f6da19
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e dell’Informazione, via Ponzio, 34/5, 20133 Milano, Italy;
Politecnico di Milano, Dipartimento di Energia, Via La Masa, 34, 20156 Milano, Italy;
Politecnico di Torino, Dipartimento di Elettronica, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy
ABSTRACT: Inductive links is the most popular solution to wirelessly send power and data from an external transmitter to implantable biomedical device. This paper proposes the optimized design of a wireless energy transfer devices, by means of an evolutionary optimization method. This procedure is developed in order to increase the transfer efficiency and the robustness of the coupling, with the aim of minimizing the average power loss. © 2011 EurAAP.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Pirisi, A.a , Mussetta, M.a b , Gruosso, G.c , Zich, R.E.a
Automated TPM-LiG modeling for WSN subsystems in marine environment
(2010) Proceedings – 2010 12th International Conference on Electromagnetics in Advanced Applications, ICEAA’10, art. no. 5651174, pp. 733-736. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-78651317112&partnerID=40&md5=d28771a8437dd989f3ca272ab68c9934
AFFILIATIONS: Politecnico di Milano, Dipartimento di Energia, Sez. Elettrica, Via La Masa 34, 20156 Milano, Italy;
Politecnico di Torino, Dipartimento di Elettronica, C.so Duca degli Abruzzi 24, 10129 Torino, Italy;
Politecnico di Milano, Dipartimento di Elettronica e dell’Informazione, via Ponzio 34/5, 20133 Milano, Italy
ABSTRACT: With the appreciating of problems related to the environmental impact evaluation of human activities, wireless sensor networks (WSNs) are emerging as suitable monitoring systems for large geographical areas, fixing new challenges in many scientific areas such as computer science, wireless communication and energy harvesting. In recent years tubular permanent magnet linear generators (TPM-LiG) have been proposed in several marine applications as a well-suited technology for power generation such as power buoys. In this work an automated soft-computing approach is presented in order to provide an optimized electromagnetic model of TPM-LiG. A prototype of tubular generator was set up and measures provided, to a large extent, a first validation of the predictive model used in the proposed automated approach. ©2010 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Pirisi, A.a , Mussetta, M.a b , Gruosso, G.c , Zich, R.E.a
Optimization of a linear generator for sea-wave energy conversion by means of a hybrid evolutionary algorithm
(2010) 2010 IEEE World Congress on Computational Intelligence, WCCI 2010 – 2010 IEEE Congress on Evolutionary Computation, CEC 2010, art. no. 5586370, . Cited 10 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-79959436420&partnerID=40&md5=a2dcc3f14b1a622b0ac9896b9aa6998d
AFFILIATIONS: Politecnico di Milano, Dipartimento di Energia, Via La Masa, 34, 20156 Milano, Italy;
Politecnico di Torino, Dipartimento di Elettronica, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy;
Politecnico di Milano, Dipartimento di Elettronica, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy
ABSTRACT: In this paper the optimization of a Tubular Permanent Magnet-Linear Generator (TPM-LiG) for energy generation is presented. The application is related to the sea wave energy generation for small sensorized buoy. The optimization process is developed by means of an hybrid evolutionary algorithm widely presented in the paper. The advantage of this algorithm is in the wide exploration of the variables space and in the effective exploitation of the fitness function. The algorithm has been tested on a benchmark case and then applied to the optimization of the here considered device. © 2010 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Pirisi, A.a , Mussetta, M.a b , Gruosso, G.c , Zich, R.E.a
Bio-inspired optimization techniques for wireless energy transfer
(2010) Proceedings – 2010 12th International Conference on Electromagnetics in Advanced Applications, ICEAA’10, art. no. 5651102, pp. 731-732. Cited 3 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-78651273552&partnerID=40&md5=a676abd70efe65d3880fae8fa65d27d6
AFFILIATIONS: Politecnico di Milano, Dipartimento di Energia, Sez. Elettrica, Via La Masa 34, 20156 Milano, Italy;
Politecnico di Torino, Dipartimento di Elettronica, C.so Duca degli Abruzzi 24, 10129 Torino, Italy;
Politecnico di Milano, Dipartimento di Elettronica e dell’Informazione, via Ponzio 34/5, 20133 Milano, Italy
ABSTRACT: This paper provides a novel approach to the design of wireless energy transfer devices, by means of an hybrid evolutionary optimization method, the recently developed Genetical Swarm Optimization. This approach is well suited in order to increase the transfer efficiency and the robustness of the coupling, with the aim of minimizing the average power loss. ©2010 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Rocco, P., Gruosso, G., Magnani, G.
Mechatronic model of oscillations in hybrid stepper motors
(2010) IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM, art. no. 5695852, pp. 726-731. Cited 2 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-79951642886&partnerID=40&md5=90a6f68f2b13f6e245a21de64d0d70a2
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e Informazione, Piazza L. da Vinci 32, 20133 Milano, Italy
ABSTRACT: Hybrid stepper motors combine the features of permanent magnet and variable reluctance motors, which makes them an attractive solution for a variety of low-cost applications. Oscillations in the phase current and in the motor position may however arise between two consecutive steps. This paper develops a model of the system, whose linearization yields closed form analytical expressions of the parameters (natural frequency and damping coefficient) characterizing such oscillations. A detailed simulation model of the system, including discontinuous effects of PWM amplification, is developed as well and validated with experimental data. The accuracy of the expression found for the oscillation parameters is also validated. © 2010 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Pirisi, A.a , Mussetta, M.a b , Gruosso, G.c , Zich, R.E.a
An optimized three phase TPM-LiG for marine applications
(2010) SPEEDAM 2010 – International Symposium on Power Electronics, Electrical Drives, Automation and Motion, art. no. 5542211, pp. 1712-1717. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-77956574581&partnerID=40&md5=1c772f41ccf51cf2215f90951ea61772
AFFILIATIONS: Politecnico di Milano, Dipartimento di Energia, Via La Masa, 34, 20156 Milano, Italy;
Politecnico di Torino, Dipartimento di Elettronica, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy;
Politecnico di Milano, Dipartimento di Elettronica, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy
ABSTRACT: In recent years linear generators have been proposed in several marine applications as a well-suited technology for power generation such as power buoys. Those kind of buoys could be used as large-scale devices in power plants and as small-size devices in electronic supply as well. In this work a numerical model of a three phase tubular permanent magnet linear generator is integrated with a Genetical Swarm Optimization algorithm in order to provide a first optimization for electronic applications. Numerical results have been reported and discussed and a generator prototype has been tested on a test bed in order to validate the predicted perfomances. © 2010 IEEE.
AUTHOR KEYWORDS: Optimization; Optimization algorithm; Tubular linear generator; Wave energy
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Brambilla, A., Gruosso, G., Redaelli, M., Gajani, G.S.
Periodic noise analysis of electric circuits: Artifacts, singularities and a numerical method
(2010) International Journal of Circuit Theory and Applications, 38 (7), pp. 689-708. Cited 9 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-77956375342&partnerID=40&md5=b1ce7f05d0c0226dc06d9b41b56e382b
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e Informazione, p.za Leonardo da Vinci, 32, I-20133 Milano, Italy
ABSTRACT: In this paper it is shown that a numerical method largely adopted for the simulation of noise in autonomous circuits is affected by singularities that manifest when the frequency at which the noise analysis is carried out approaches a harmonic of the autonomous circuit. The resulting noise power spectral density (PSD) is thus characterized by spurious spikes. The presence of these singularities is for the first time justified from an analytical standpoint and their effects are shown by simulating some oscillators, employed as benchmarks. Furthermore, the presented approach justifies the 1/(f s – f)2 shape of the PSD of noise at the output when the fs frequency approaches the f fundamental of a stable oscillator and the 1/| fs – f |3 shape when the effects of flicker noise are manifest. Copyright © 2009 John Wiley & Sons, Ltd.
AUTHOR KEYWORDS: Floquet theory; Noise analysis; Oscillators; Periodic circuits; Periodic noise analysis; Phase noise; Small signal analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
FSSA: Fast steady-state algorithm for the analysis of mixed analog/digital circuits
(2010) IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 29 (4), art. no. 5433754, pp. 528-537. Cited 5 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-77949883388&partnerID=40&md5=93f5d0e1648e037cef7ca65764ebd17e
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milano I20133, Italy
ABSTRACT: The shooting method is largely employed to determine the steady-state working condition of both autonomous and nonautonomous circuits. In general, the conventional shooting method employs the Newton algorithm to estimate a better approximation of the steady-state working condition. The Newton algorithm requires the computation of the Jacobian matrix and this seriously limits the use of the conventional shooting method to solve medium/large scale circuits. In this paper, an approach to efficiently determine the shooting matrix is presented. It is shown that the approach is also adequate to deal with mixed analog/digital circuits. © 2010 IEEE.
AUTHOR KEYWORDS: Leading dynamics; Mixed analog/digital circuits; Shooting method; Steady-state analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
Robust harmonic-probe method for the simulation of oscillators
(2010) IEEE Transactions on Circuits and Systems I: Regular Papers, 57 (9), art. no. 5439844, pp. 2531-2541. Cited 4 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-77957750805&partnerID=40&md5=37c663538b06b68b9ea06e15bc3d6f91
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, 20133 Milano, Italy
ABSTRACT: This paper considers the harmonic balance method (HB) in conjunction with the probe insertion technique. In general, the nonlinear equations modeling the circuit in the frequency domain are solved with the Newton iterative method. It is known that, in many cases, probe insertion in the original circuit shows better convergence properties of the Newton method and therefore of the harmonic balance when simulating autonomous circuits. The probe technique is considered here in detail, and numerical aspects are discussed mainly for what concerns the condition number of the Jacobian matrix related to the Newton method. The probe technique is then improved by exploiting properties of the power exchanged between the probe and the circuit in which it is inserted; moreover, an automatic probe insertion mechanism is detailed. © 2010 IEEE.
AUTHOR KEYWORDS: Frequency-domain simulation; harmonic balance method (HB); injection locking; oscillators; probes
DOCUMENT TYPE: Article
SOURCE: Scopus

Brambilla, A.a , Gruosso, G.a , Redaelli, M.A.a , Gajani, G.S.a , Caviglia, D.D.b
Improved small-signal analysis for circuits working in periodic steady state
(2010) IEEE Transactions on Circuits and Systems I: Regular Papers, 57 (2), art. no. 4806052, pp. 427-437. Cited 20 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-76849086627&partnerID=40&md5=e6ebcb9b4c1ebf3f6f20547fec62d46f
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milano, Italy;
Dipartimento di Biofisica Ed Elettronica, Università di Genova, Genova, Italy
ABSTRACT: This paper considers the formulation of the variational model (VM) of autonomous circuits (oscillators) working in periodic steady-state conditions. The shooting method, which is largely used to compute the solution in the time domain when the VM is forced by a small-signal perturbation, is studied. The proposed analytical approach can be exploited to improve accuracy in the simulation of the effects of noise sources. In particular, we justify from an analytical standpoint the adoption of a suitable periodicity constraint in the shooting method. We exploit the properties of block circulant matrices that naturally arise in the description of the problem. We prove that the frequency of the small-signal perturbation must be different from that of the unperturbed oscillator to avoid inaccuracy of the shooting method due to the existence of singularities in the VM formulation, and derive a method that allows us to get closer to the singularity. © 2006 IEEE.
AUTHOR KEYWORDS: Autonomous circuits; Block circulant matrices; Periodic small-signal analysis; Phase noise; Shooting method; Variational model (VM)
DOCUMENT TYPE: Article
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
Multi-Probe harmonic balance method to simulate coupled oscillators
(2009) 3rd International Conference on Signals, Circuits and Systems, SCS 2009, art. no. 5414185, . Cited 2 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-77951489798&partnerID=40&md5=d42807cf216e0d07e8a22b1c0424e52a
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e Informazione, p.za Leonardo da Vinci, 32, 120133, Milano, Italy
ABSTRACT: In this paper the harmonic balance method is considered in conjunction with the probe insertion technique. In general, the nonlinear equations modeling the circuit in the frequency domain are solved with the Newton iterative method. Conventional probe insertion technique has become popular and implemented in commercial analog simulators, since in many cases it shows better convergence behaviour of the Newton method and, therefore, of the harmonic balance one applied to autonomous circuits. The conventional probe technique, which is based on the insertion of a single probe, is here considered in detail, improved and extended through the insertion of two distinct probes working at two different frequencies with non necessarily an integer ratio. This improved version is exploited to compute the steady state working condition of coupled oscillators that operate in a pulling condition and that can switch to a locking one according to variations of circuit parameters. © 2009 IEEE.
AUTHOR KEYWORDS: Coupled oscillators; Harmonic balance; Probe insertion; Pulling-locking modes
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Pirisi, A.a , Gruosso, G.b , Zich, R.E.a
Novel modeling design of three phase tubular permanent magnet linear generator for marine applications
(2009) POWERENG 2009 – 2nd International Conference on Power Engineering, Energy and Electrical Drives Proceedings, art. no. 4915209, pp. 78-83. Cited 9 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-70349307500&partnerID=40&md5=03de02466f049dd4da096ba16c6f1241
AFFILIATIONS: Politecnico di Milano, Dipartimento di Energia, Italy;
Politecnico di Milano, Dipartimento di Elettronica e dell’ Informazione, Italy
ABSTRACT: In recent years linear generators have been proposed in several marine applications as a well-suited technology for power generation such as power buoys. Those kinds of buoys could be used as large-scale devices in power plants and as small-size devices in electronic supply as well. In this work a three phase tubular permanent magnet linear generator is analyzed to supply electronic devices such as sensorial buoys with energy scavenging. A soft-computing algorithm based on a finite element method has been developed and a parametric approach is presented in order to provide a first optimization for electronic applications. Numerical results have been reported and discussed in detail.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
Determination of floquet exponents for small-signal analysis of nonlinear periodic circuits
(2009) IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 28 (3), art. no. 15, pp. 447-451. Cited 9 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-60749128721&partnerID=40&md5=0c94c7dcd525ed2ca3b68c396fb93833
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, 20133 Milano, Italy
ABSTRACT: This paper describes an approach to determine the Floquet exponents and the related eigenfunctions of linear time-varying circuits, that represent a vehicle to implement the variational model of periodic nonlinear circuits. The Floquet exponents and eigenfunctions allow us to exploit the structure of the analytical solution of the linear time-varying circuit and, as shown, yield an efficient solution. The proposed approach allows the calculation of the Floquet exponents directly and is developed from the harmonic-balance formulation adopted to find the steady-state solution of the nonlinear periodic circuit. © 2006 IEEE.
AUTHOR KEYWORDS: Floquet theory; Harmonic balance (HB); Periodic circuits; Small-signal analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Delinchant, B.a , Gruosso, G.b , Wurtz, F.a
Two levels modeling for the optimization of electromagnetic actuators
(2009) IEEE Transactions on Magnetics, 45 (3), art. no. 4787296, pp. 1724-1727. Cited 7 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-61449268157&partnerID=40&md5=fd7e40078a5308c7dc5eaa7da517090b
AFFILIATIONS: G2ELab Grenoble Electrical Engineering Lab., ENSE3, 38402 Grenoble, France;
Politecnico di Milano, Dipartimento di Elettronica e Informazione, Piazza Leonardo da Vinci, 32-20133 Milano, Italy
ABSTRACT: In this paper, a two-stage modelling, to ensure a good and fast optimization procedure for microdevices, is presented. This methodology is supported by three noncommercial software. The first one is dedicated to analytical modelling of non ferromagnetic electromagnetic devices, the second one is dedicated to numerical modelling of electromagnetic devices, and the last is dedicated to constrained-based optimization. Issues and solutions of such a methodology are highlighted, and illustrated by designing a matrix of actuators for an adaptive optic. © 2006 IEEE.
AUTHOR KEYWORDS: Electromagnetic MEMS; Multilevel modeling; Optimal design
DOCUMENT TYPE: Article
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
Determination of floquet exponents for small-signal analysis of nonlinear periodic circuits
(2009) IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 28 (1), pp. 447-451.
http://www.scopus.com/inward/record.url?eid=2-s2.0-77955179645&partnerID=40&md5=40b9abaa82b3e337b0c1392b038985f3
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, 20133 Milano, Italy
ABSTRACT: This paper describes an approach to determine the Floquet exponents and the related eigenfunctions of linear time-varying circuits, that represent a vehicle to implement the variational model of periodic nonlinear circuits. The Floquet exponents and eigenfunctions allow us to exploit the structure of the analytical solution of the linear time-varying circuit and, as shown, yield an efficient solution. The proposed approach allows the calculation of the Floquet exponents directly and is developed from the harmonic-balance formulation adopted to find the steady-state solution of the nonlinear periodic circuit. © 2009 IEEE.
AUTHOR KEYWORDS: Floquet theory; Harmonic balance (HB); Periodic circuits; Small-signal analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S., Redaelli, M.
QR factorisation in the shooting method
(2008) 4th European Conference on Circuits and Systems for Communications, ECCSC ’08, art. no. 4611670, pp. 172-175.
http://www.scopus.com/inward/record.url?eid=2-s2.0-53749095194&partnerID=40&md5=6870c284acabb7ef0539bb391bad2569
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, P.za Leonardo da Vinci, 32, I20133, Milano, Italy
ABSTRACT: Radio frequency (RF) applications in consumer electronics require solid methods for the computation of the steady state behaviour in autonomous and non autonomous circuits. The shooting method (SH) is possibly the most important steady state time domain numerical method currently employed in circuit simulation. We show that SH requires great care in the choice and use of matrix factorization methods. In particular, the advantages of QR over the more standard and widely employed LU method are shown. ©2008 IEEE.
AUTHOR KEYWORDS: Periodic circuits; Qr decomposition; Shooting method; Steady state analysis
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Gruosso, G., Brambilla, A.
Magnetic core model for circuit simulations including losses and hysteresis
(2008) International Journal of Numerical Modelling: Electronic Networks, Devices and Fields, 21 (5), pp. 309-334. Cited 2 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-52449118223&partnerID=40&md5=c18547403ed49555dd71fb2c6905b643
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, p.za Leonardo da Vinci 32, 120133 Milano, Italy
ABSTRACT: This paper presents a magnetic core model that accounts the effects due to nonlinearity, hysteresis and eddy currents. The model is suited to circuit simulation and can be implemented as a subcircuit. To test the proposed implementation the results obtained by simulating a power square wave generator (Royer oscillator) have been compared with measurements on a laboratory prototype. Copyright © 2008 John Wiley & Sons, Ltd.
AUTHOR KEYWORDS: Circuit simulation; Eddy currents; Hysteresis; Magnetic code model
DOCUMENT TYPE: Article
SOURCE: Scopus

Freschi, F.a , Gruosso, G.b , Repetto, M.a
Force computation by hybrid cell method
(2008) IEEE Transactions on Magnetics, 44 (6), art. no. 4526867, pp. 1198-1201. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-44049104078&partnerID=40&md5=93ad61ff28ee98fb07cd4056eaa5fd08
AFFILIATIONS: Dipartimento di Ingegneria Elettrica, Politecnico di Torino, I-10129 Torino, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, I-20133 Milano, Italy
ABSTRACT: Force computation in magnetostatic structures is approached by surface integration of Maxwell stress tensor. Two formulations based on the cell method are presented: the first one with volume discretization and the second one with a hybrid integral scheme. A case with permanent magnets where experimental values of force are available is used as benchmark for comparison of both accuracy and computational cost of the two approaches. © 2008 IEEE.
AUTHOR KEYWORDS: Cell method; Green function; Hybrid formulations; Magnetic forces
DOCUMENT TYPE: Article
SOURCE: Scopus

Alotto, P.a , Gruosso, G.b , Moro, F.a , Repetto, M.c
A boundary integral formulation for eddy current problems based on the cell method
(2008) IEEE Transactions on Magnetics, 44 (6), art. no. 4526789, pp. 770-773. Cited 3 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-44049095019&partnerID=40&md5=a47e47b2e68b5932e9bbe47910234789
AFFILIATIONS: Dipartimento di Ingegneria Elettrica, Università di Padova, 35131 Padova, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, 20133 Milano, Italy;
Dipartimento di Ingegneria Elettrica, Politecnico di Torino, 10129 Torino, Italy
ABSTRACT: A finite formulation for 3-D eddy current problems in unbounded domains is presented. This approach is based on the discrete magnetic vector potential to model conducting regions and on the magnetic scalar potential to model free space. In order to avoid meshing of the air region, integral boundary conditions coupling Dirichlet and Neumann data are used. A numerical strategy based on the Schur complement approach is used in order to improve the convergence properties of the iterative solver. Simulation results show that the proposed approach is both fast and accurate. © 2008 IEEE.
AUTHOR KEYWORDS: Cell method; Eddy current; Hybrid method; Magnetic field; Unbounded domains
DOCUMENT TYPE: Article
SOURCE: Scopus

Alotto, P.a , Gruosso, G.b , Moro, F.a , Repetto, M.c
Three-dimensional eddy current analysis in unbounded domains by a DEM-BEM formulation
(2008) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 27 (2), pp. 460-466.
http://www.scopus.com/inward/record.url?eid=2-s2.0-40549123718&partnerID=40&md5=dce75f1cdad6ce0e84cd34c463490e66
AFFILIATIONS: Dipartimento di Ingegneria Elettrica, Università di Padova, Padova, Italy;
Dipartimento di Elettronica ed Informazione, Politecnico di Milano, Milano, Italy;
Dipartimento di Ingegneria Elettrica, Politecnico di Torino, Torino, Italy
ABSTRACT: Purpose – To propose a novel 3D hybrid approach, based on a discrete formulation of Maxwell equations (the cell method – CM), suitable for solving eddy current problems in unbounded domains. Design/methodology/approach – Field equations for magnetodynamics are expressed directly in algebraic form thanks to the CM. The eddy current problem inside bulk conductors is formulated in terms of discrete modified vector potential, whereas magnetic scalar potential is used in order to model the free space. The CM is coupled to the boundary element method by using a surface boundary operator, which maps the surface magnetic fluxes to the surface magnetic scalar potentials. This leads to a unique set of linear equations to be solved in terms of discrete potentials. The eddy currents in bulk conductors are then obtained from discrete potentials. Findings – It is shown that formulation of hybrid approaches can be simplified by expressing field equations directly in algebraic form without need of weighted residual techniques. An original strategy, based on Green’s formula for the magnetic scalar potential, is proposed in order to couple conducting parts to the exterior domain. Research limitations/implications – Conducting bodies with multiply connected parts cannot be modelled by the proposed approach, since it is based on the magnetic scalar potential. The resulting global matrix is partially dense and non-symmetric; therefore, standard iterative solvers such as GMRES have to be used. Practical implications – The proposed approach can be suitably used for analyzing eddy current problems involving models with high degree of complexity, large air domains and moving parts. These are typical of induction heating processes. Originality/value – This paper proposes a new 3D hybrid approach, based on a discrete formulation of Maxwell equations. A novel coupling strategy relying on integral electromagnetic variables, i.e. magnetic fluxes and magnetic scalar potentials, is devised in order to solve uniquely for eddy currents inside conducting bodies. © Emerald Group Publishing Limited.
AUTHOR KEYWORDS: Eddy currents; Electromagnetic induction; Heat treatment; Magnetic fields
DOCUMENT TYPE: Article
SOURCE: Scopus

Gruosso, G.a , Repetto, M.b
Magnetostatic solution by hybrid technique and fast multipole method
(2008) Physica B: Condensed Matter, 403 (2-3), pp. 368-371. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-37349102636&partnerID=40&md5=54bf62564d64487afb100592affffcd3
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e Informazione, I-20133 Milano, Italy;
Politecnico di Torino, Dipartimento di Ingegneria Elettrica, C.so Duca Abruzzi 24, I-10129 Torino, Italy
ABSTRACT: The use of fast multipole method (FMM) in the solution of a magnetostatic problem is presented. The magnetostatic solution strategy is based on finite formulation of electromagnetic field coupled with an integral formulation for the definition of boundary conditions on the external surface of the unstructured mesh. Due to the hypothesis of micromagnetic problem, the resulting matrix structure is sparse and integral terms are only on the RHS. Magnetic surface charge is used as source of these integral terms and is localized on the faces between tetrahedra. The computation of the integral terms can be performed by analytical formulas for the near field contributes and by FMM for far field ones. © 2007 Elsevier B.V. All rights reserved.
AUTHOR KEYWORDS: Cell method; Fast multipole method; Hybrid techniques; Micromagnetics
DOCUMENT TYPE: Article
SOURCE: Scopus

Canova, A.a , Freschi, F.a , Repetto, M.a , Gruosso, G.b
Coupling of finite formulation with integral techniques
(2008) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 27 (1), pp. 37-46.
http://www.scopus.com/inward/record.url?eid=2-s2.0-38149000813&partnerID=40&md5=b0a2afdfd3afa11dfc95120424d79e51
AFFILIATIONS: Dipartimento di Ingegneria Elettrica, Politecnico di Torino, Torino, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milano, Italy
ABSTRACT: Purpose: The paper aims to describe the coupling of magnetostatic finite formulation of electromagnetic field with two integral methods. Design/methodology/approach: The first hybrid scheme is based on Green’s function applied to magnetization source while the other one is based on a magnetic scalar potential boundary element method. A comparison of the two techniques is performed on a benchmark case with analytical solution, on a 2D multiply-connected problem and on an industrial case where measurements are available. Findings: The proposed hybrid approaches have proved to be effective techniques to solve open boundary non-linear magnetostatic problems. Similar convergence speed with respect to the number of unknowns is found for both schemes Originality/value: The paper shows the effectiveness of hybrid schemes applied to the finite formulation, assessing their performances on various test cases. © Emerald Group Publishing Limited.
AUTHOR KEYWORDS: Electromagnetic fields; Electromagnetism; Numerical analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Mitolo, M.a b , Gruosso, G.c , Canova, A.d , Tartaglia, M.d
Evaluation of voltage exposures due to AC/DC stray currents
(2007) Conference Record – IAS Annual Meeting (IEEE Industry Applications Society), art. no. 4347984, pp. 1517-1521.
http://www.scopus.com/inward/record.url?eid=2-s2.0-47849126157&partnerID=40&md5=4988ef9da7798df12b3797ac0b8e9740
AFFILIATIONS: IEEE;
Chu and Gassman, 559 Union Ave., Middlesex, NJ 08846, United States;
Dipartimento Elettronica e Informazione, Politecnico di Milano, P.le Leonardo da Vinci, 32, 20133 Milano, Italy;
Dipartimento Ingegneria Elettrica, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy
ABSTRACT: Stray currents leaking from DC and AC electrical installations may flow through buried metal works towards their sources. Such currents may circulate through intentional electrodes, for example dwelling units and railways grounding systems, but also through building and tunnels metal frames, as well as, water and gas utility pipelines. Besides the corrosion phenomena, triggered over the aforementioned metal parts by DC currents, the stray currents may energize these conductive parts, exposing persons to touch voltages. This paper proposes an approach to evaluate the voltage exposure appearing on the aforesaid metal parts, based on the estimation of an appropriate ground-resistance matrix. This matrix, used in conjunction with a system of circuit equations, will yield voltage and current associated to the interfering electrodes. In the case of standard electrode configurations (e.g. spherical, cylindrical, etc.) the evaluation of the above mentioned matrix may be analytically carried out [1]. To take into account complex electrode geometries and/or non-homogeneous soil conditions, numerical elaboration based on the method of the moments [2] will be employed. History cases are presented and discussed. © 2007 IEEE.
AUTHOR KEYWORDS: Earth systems; Electrodes interaction; Method of the moments; Stray current; Touch voltages
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Freschi, F.a , Repetto, M.a , Gruosso, G.b , Maffucci, A.c , Villone, F.c , Zamboni, W.c
Investigation of low-frequency behaviour of two surface integral full-Maxwell formulations
(2007) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 26 (3), pp. 842-858.
http://www.scopus.com/inward/record.url?eid=2-s2.0-34547296543&partnerID=40&md5=f916ee47c0b559ac5700e57fa8377026
AFFILIATIONS: Politecnico di Torino, Torino, Italy;
Politecnico di Milano, Milano, Italy;
EURATOM/ENEA/CREATE Association, DAEIMI, Università Degli Studi di Cassino, Cassino, Italy
ABSTRACT: Purpose – To apply two different integral formulations of full-Maxwell’s equations to the numerical study of interconnects in a low-frequency range and compare the results. Design/methodology/approach – The first approach consists of a surface formulation of the full-Maxwell’s equations in terms of potentials, giving rise to a surface electric field integral equation. The equation, given in a weak form, is solved by using a finite element technique. The solenoidal and non-solenoidal components of the electric current density are separated using the null-pinv decomposition to avoid the low-frequency breakdown. The second model is an extension of partial element equivalent circuit technique to unstructured meshes allowing the use of triangular meshes. Two systems of meshes tied by duality relations are defined on multiconductor systems. The key point in the definition of the equivalent network is to associate the pair primal edge/dual face to a circuit branch. Solution of the resulting electrical network is performed by a modified nodal analysis method and regularization of the outcoming matrix is accomplished by standard techniques based on the addition of suitable resistors. Findings – Both the formulation have a regular behaviour at very low frequency. This is automatically achieved in the first approach by using the null-pinv decomposition. Research limitations/implications – Surface sources of fields. Originality/value – Two different integral formulations of full-Maxwell’s equations for the numerical study of interconnects are compared in terms of low-frequency behaviour. © Emerald Group Publishing Limited.
AUTHOR KEYWORDS: Integral equations; Numerical analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Canova, A.a , Gruosso, G.b
3D source simulation method for static fields in inhomogeneous media
(2007) International Journal for Numerical Methods in Engineering, 70 (9), pp. 1096-1111.
http://www.scopus.com/inward/record.url?eid=2-s2.0-34249717926&partnerID=40&md5=615562eb0eb022a141fadce54e06f087
AFFILIATIONS: Dipartimento di Ingegneria Elettrica, Politecnico di Torino, c.so Duca Degli Abruzzif 24, Torino I-10129, Italy;
Dipartimento di – Elettronica e Informazione, Politecnico di Milano, p.zza Leonardo da Vinci 32, Milamo I-20133, Italy
ABSTRACT: In this paper, an integral approach based on the source simulation method (SSM) for the solution of three dimensional (3D) static electric fields is presented. This is an extension of the well-known charge simulation method to the electric and current static fields. The formulation allows the solution of 3D electrostatic or static current field problems, where several perfectly conducting bodies (electrodes) are placed in inhomogeneous media. Only electrode surfaces and dielectric interfaces need to be discretized by triangular elements. Matrix coefficients are accurately evaluated by using closed integral forms of 1/r and of grad (1/r). Dirichlet and Neumann conditions can be imposed on the different conducting bodies; in particular, floating potential problem can also be solved. The method of images allows ground plane to be taken into account. The procedure has been applied to several practical cases and it represents an efficient tool for the evaluation of lumped circuit parameters such as capacitances of 3D conducting bodies and ground resistances of grounding system. Copyright © 2006 John Wiley & Sons, Ltd.
AUTHOR KEYWORDS: Capacitance; Charge simulation method; Dielectric; Electrostatic; Grounding system; Static field
DOCUMENT TYPE: Article
SOURCE: Scopus

Lahaye, D.a , Canova, A.b , Gruosso, G.c , Repetto, M.b
Adaptive manifold-mapping using multiquadric interpolation applied to linear actuator design
(2007) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 26 (2), pp. 225-235. Cited 4 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-34147206741&partnerID=40&md5=010328f42e55199833b1b56df3aa0818
AFFILIATIONS: Centrum voor Wiskunde en Informatica (CWI), Amsterdam, Netherlands;
Dipartimento di Ingegneria Elettrica, Politecnico di Torino, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milano, Italy
ABSTRACT: Purpose – This work aims to present a multilevel optimization strategy based on manifold-mapping combined with multiquadric interpolation for the coarse model construction. Design/methodology/approach – In the proposed approach the coarse model is obtained by interpolating the fine model using multiquadrics in a small number of points. As the algorithm iterates the response surface model is improved by enriching the set of interpolation points. Findings – This approach allows to accurately solve the TEAM Workshop Problem 25 using as little as 33 finite element simulations. Furthermore, it allows a robust sizing optimization of a cylindrical voice-coil actuator with seven design variables. Research limitations/implications – Further analysis is required to gain a better understanding of the role that the initial coarse model accuracy plays in the convergence of the algorithm. The proposed model allows to carry out such analysis by varying the number of points included in the initial response surface model. The effect of the trust-region stabilization in the presence of manifolds of equivalent solutions is also a topic of further investigations. Originality/value – Unlike the closely related space-mapping algorithm, the manifold-mapping algorithm is guaranteed to converge to a fine model optimal solution. By combining it with multiquadric response surface models, its applicability is extended to problems for which other kinds of coarse model such as lumped parameter approximations for instance are tedious or impossible to construct. © Emerald Group Publishing Limited.
AUTHOR KEYWORDS: Actuators; Interpolation; Optimization techniques
DOCUMENT TYPE: Article
SOURCE: Scopus

Freschi, F.a , Gruosso, G.b , Repetto, M.a
Unstructured PEEC formulation by dual discretization
(2006) IEEE Microwave and Wireless Components Letters, 16 (10), art. no. 882407, pp. 531-533. Cited 4 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-55149121594&partnerID=40&md5=954dd0155b1acfc66311d7e7b198625c
AFFILIATIONS: Politecnico di Torino, Turin I-10129, Italy;
Politecnico di Milano, Milano 20158, Italy
ABSTRACT: This letter presents a new lumped parameter approach for the solution of the electromagnetic problem of a system of conductors lying in a homogeneous region. By exploiting duality relations between two systems of meshes, an equivalent network of lumped parameters is obtained. This approach is conceptually equivalent to the partial element equivalent circuit formulation but it can overcome the limits imposed by a regular discretization present in its original version. Details about computation of lumped parameters and definition of equivalent network are given. Results obtained on two configurations referenced in the literature are finally discussed © 2001-2012 IEEE.
AUTHOR KEYWORDS: Dual discretization; partial element equivalent circuit (PEEC); unstructured mesh
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Giuffrida, C.a , Gruosso, G.b c , Repetto, M.a d e
Finite formulation of nonlinear magnetostatics with integral boundary conditions
(2006) IEEE Transactions on Magnetics, 42 (5), pp. 1503-1511. Cited 12 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-33646450112&partnerID=40&md5=7e9fe2b4a738a161ce3837f30e6d1041
AFFILIATIONS: Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, 10129 Torino, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, 20133 Milano, Italy;
Dipartimento di Elettronica ed Informazione, Politecnico di Milano, Milano, Italy;
Department of Fundamentals of Electrical Engineering, Italy;
Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, Torino, Italy
ABSTRACT: This paper describes two hybrid methods coupling finite formulation of electromagnetic fields (FFEF) in a bounded domain to integral boundary conditions taking into account far field conditions. The two hybrid techniques use different boundary conditions: the first formulation is based on Green’s function applied to magnetization source inside bounded domain while the other one is based on a boundary-element method on its external surface. Details about the coupling terms are given and handling of different magnetization sources is described, including the fictitious magnetization sources coming from nonlinear solutions. The proposed methods are validated versus different benchmark cases. Comparisons between the two techniques have been performed using different criteria (accuracy and convergence, memory requirements, etc.). © 2006 IEEE.
AUTHOR KEYWORDS: Boundary-element method; Finite formulation of electromagnetic fields; Green’s function; Hybrid formulations; Nonlinearity
DOCUMENT TYPE: Article
SOURCE: Scopus

Canova, A.a , Gruosso, G.b , Tartaglia, M.a
Insulated joint for corrosion protection of buried subway gallery structure: Consideration on cable ground connection
(2006) IEEE Transactions on Power Delivery, 21 (2), pp. 966-970. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-33645729833&partnerID=40&md5=3321429c41069a1a207d59c538d422e1
AFFILIATIONS: Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, Torino 10129, Italy;
Dipartimento di Elettronica ed Informatica, Politecnico di Milano, Milano 20133, Italy
ABSTRACT: Protection against corrosion of a subway’s metallic structure can be performed by insulated joints at the interface between galleries and stations. A preliminary analysis shows some differences in stray current flowing and a possible improvement of protection depending on the joint region configuration. This analysis is performed by means of a commercial three-dimensional finite-element method. A consequence of using insulated joints is a suitable grounding of the sheaths belonging to power and signal cables laying inside the gallery and particular care in connecting them to ground electrical masses or other metallic structures in order to avoid shunting insulated joints. Induced voltages and currents must be predicted to avoid any danger in both under-rated and fault conditions. © 2006 IEEE.
AUTHOR KEYWORDS: Corrosion; Railway; Stray current
DOCUMENT TYPE: Article
SOURCE: Scopus

Gruosso, G.a , Repetto, M.b
Implementation of a network model of hysteresis
(2006) Physica B: Condensed Matter, 372 (1-2), pp. 53-56.
http://www.scopus.com/inward/record.url?eid=2-s2.0-30844461229&partnerID=40&md5=4f88ca88fb454b532af10c729c018a9b
AFFILIATIONS: Dipartimento Elettronica e Informazione, Politecnico di Milano, P.za Leonardo da Vinci 32, I-20133 Milano, Italy;
Dipartimento Ingegneria Elettrica, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy
ABSTRACT: A network model of hysteresis based on elementary cells made up with piece-wise linear resistors and a linear capacitor has been presented in the literature and its theoretical properties have been investigated. This model allows to simulate hysteresis in a circuit solver without requiring any modification to its source code. Despite its appealing features, some cautions must be used for the treatment of the interface between the model and the rest of the circuit and for the handling of nonlinear resistors which can introduce some convergence problems in the network solution. These topics are investigated and some results on a simple test case are presented and discussed. © 2005 Elsevier B.V. All rights reserved.
AUTHOR KEYWORDS: Network model of hysteresis; Nonlinear circuit; Static hysteresis model
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Freschi, F.a , Gruosso, G.b , Repetto, M.a
Use of finite formulation of electromagnetic field for solving PEEC problems on unstructured grids
(2005) ICEAA 2005 – 9th International Conference on Electromagnetics in Advanced Applications and EESC 2005 – 11th European Electromagnetic Structures Conference, pp. 455-458. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-34547290603&partnerID=40&md5=4f654ee5dc4114061dbc624d123411db
AFFILIATIONS: Dipartimento di Ingegneria Elettrica, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
ABSTRACT: Finite Formulation of Electromagnetic Fields allows to define an algebraic form of Maxwell’s equations on an unstructured discretization system. This characteristic is here exploited by defining an equivalent circuit for an unstructured mesh of surface electrodes in an homogeneous dielectric region The constitutive equation of this partial components can be written by means of the electric field integral equation. In this way a generalization of the well known PEEC technique to the case of triangular discretization is obtained. Some results are presented on benchmark cases showing a good agreement with the ones available in the literature.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Canova, A.a , Freschi, F.a , Gruosso, G.b , Vusini, B.a
Genetic optimisation of radial eddy current couplings
(2005) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 24 (3), pp. 767-783. Cited 2 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-22644447613&partnerID=40&md5=a423733f89c0cc60a1675d009ed39af7
AFFILIATIONS: Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, Turin, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milan, Italy
ABSTRACT: Purpose – The purpose of this paper is to obtain a fully analytical model of an eddy current coupler and to use it in a multi-objective optimisation algorithm. Design/methodology/approach – Analytical expressions of device performances are adopted in the objective function and are obtained from a closed solution of the field problem. The optimisation has been carried out by considering both the torque and the momentum of inertia of the object. Two different structures have been considered. Findings – A fully analytical expression of the torque has been obtained for two different geometrical configurations. The optimisation procedure has been used to compare these structures and it is possible to observe that the DSPM performances are better than the SSPM ones. Research limitations/implications – To obtain a closed form of the torque function, the non-linearities of the iron have been neglected. Nevertheless, in the optimisation procedure has been limited the magnetic flux density in the iron core to a feasible value in the linear part of the ferromagnetic characteristic. The thermal effects have been neglected. Pratical implications – In the industry, eddy current couplers can be used as transmission, dampers and brakes. The use of objective functions (OFs) in a closed formulation allows to perform a light optimisation from the point of view of the time computation and to drastically increase the development efficiency. Originality/value – In this paper, a model for computing the electromagnetic behaviour of eddy current couplers is presented. The optimisation of both the torque and the inertia momentum allows to obtain good static and dynamic performances. © Emerald Group Publishing Limited.
AUTHOR KEYWORDS: Eddy currents; Optimization techniques
DOCUMENT TYPE: Article
SOURCE: Scopus

Canova, A.a , Gruosso, G.b , Repetto, M.a
An integral approach based on dual discretization and method of moment for the solution of static electric field
(2005) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 24 (2), pp. 446-457.
http://www.scopus.com/inward/record.url?eid=2-s2.0-20444458291&partnerID=40&md5=943bfbe8c3865921af5e45639f2d09a2
AFFILIATIONS: Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, Torino, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milano, Italy
ABSTRACT: Purpose – The scope of the work is to provide an hybrid numerical technique for the solution of electric field. Design/methodology/approach – In this paper an integral approach for the solution of static electric field based on a dual discretization (DD) and on a surface method of moment (MoM) is presented. The proposed technique is applied to the solution of 3D electric field problems where different perfectly conducting bodies are placed in a homogeneous and isotropic medium. The approach is also extended to the analysis of static current field. In the presented formulation MoM is applied on a surface domain which is discretized according to a baricentrical dual scheme. Findings – The procedure has been applied to several practical cases and it represents an efficient tool for the evaluation of lumped circuit parameters as capacitances of 3D conducting bodies and ground resistance of grounding systems. Research limitations/implications – The formulation presented in the paper is limited to the calculus of electric field in homogeneous media. For future development the authors are working in order to include non-homogeneous media. Practical implications – The proposed approach aids the designer of electrical systems as large scale grounding systems or integrated circuit connections in the calculations of lumped electrical parameters. Originality/value – The originality of the paper lies in the coupling of MoM with finite formulation and DD. © Emerald Group Publishing Limted.
AUTHOR KEYWORDS: Electric fields; Integral equations; Meshes; Method of moments
DOCUMENT TYPE: Article
SOURCE: Scopus

Gruosso, G.a , Repetto, M.b
Identification and simulation of a circuit-based model of magnetic hysteresis
(2005) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 24 (2), pp. 534-545.
http://www.scopus.com/inward/record.url?eid=2-s2.0-20444482398&partnerID=40&md5=c68e98b1c8f1456d0472e192848f4dbb
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milano, Italy;
Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, Torino, Italy
ABSTRACT: Purpose – The scope of the work is to provide an identification procedure for an hysteresis model based on nonlinear circuit cells. Design/methodology/approach – An identification procedure for an hysteresis model based on nonlinear circuit cells is presented. The response of elementary cell is equal to a generalized play operator. The procedure allows the identification of the limit symmetric hysteresis loop and of minor loops. The identification procedure is based on the relationship between the circuit parameters and the discretization of the first derivative of the BH curve by means of a staircase function. Findings – The model obtained is employed for the simulation of soft magnetic composite material cores under different supply voltage waveforms. The proposed identification procedure is able to define an accurate model of an hysteretic material with a low number of elemental network cells. The identification algorithm is simple and makes use of the limit hysteresis cycle only. Symmetric minor loops are used to tune “soft” operators for the correct reconstruction of cycles which do not reach saturation. Research limitations/implications – The model is limited to scalar and static hysteresis model. Practical implications – The model obtained can be used in network simulator like SPICE in order to model circuits in which magnetic devices are involved. Originality/value – The circuit hysteresis model has been presented in literature, while its identification is newly proposed by the authors. © Emerald Group Publishing Limited.
AUTHOR KEYWORDS: Magnetic measurement; Modelling
DOCUMENT TYPE: Article
SOURCE: Scopus

Gruosso, G.a , Repetto, M.b
Identification method for a circuit model of scalar static hysteresis
(2004) IEEE Transactions on Magnetics, 40 (6), pp. 3467-3473. Cited 4 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-9644302994&partnerID=40&md5=a36c5c965b8624b6f7d7813cfb9bdaa4
AFFILIATIONS: Dipartimento di Elettronica, Politecnico di Milano, 32-I-20133 Milano, Italy;
Dipto. Ingegneria Elettrica I., Politecnico di Torino, 24-10-129 Torino, Italy
ABSTRACT: We present a new identification procedure for a hysteresis model based on nonlinear circuit cells. The response of elementary cells is equal to a generalized play operator. The procedure identifies exactly the limit symmetric hysteresis loop and can minimize the reconstruction error on minor loops. We present test cases for three different soft magnetic materials with peculiar behavior and we discuss the results.
AUTHOR KEYWORDS: Circuit model of hysteresis; Hysteresis; Identification; Soft magnetic material
DOCUMENT TYPE: Article
SOURCE: Scopus

Schofield, N.a d , Canova, A.b , Gruosso, G.b , Repetto, M.b , Ottella, M.c
The application of soft magnetic composites to the design of tubular linear actuators
(2004) International Journal of Applied Electromagnetics and Mechanics, 19 (1-4), pp. 225-229. Cited 5 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-2442562437&partnerID=40&md5=715fa243f05a1f7a85632c0abd08a9db
AFFILIATIONS: Dept. of Electronic Engineering, University of Sheffield, Sheffield, United Kingdom;
Dipto. Ingegneria Elettrica Indust., Politecnico di Torino, Torino, Italy;
Centro Ricerche Fiat, Orbassano, Torino, Italy;
Department of Electronic Engineering, University of Sheffield, Sheffield, S1 3JD, United Kingdom
ABSTRACT: The paper presents the design synthesis and construction of a tubular linear, permanent magnet actuator for automotive applications. The application of soft magnetic composites in permanent magnet machines is discussed, since conventional lamination techniques are cost prohibitive for the tubular linear topology considered. The linking of analytic and finite element techniques in the design synthesis is presented along with characterisation test data from a prototype actuator constructed to validate the design procedure.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Canova, A.a , Gruosso, G.b , Repetto, M.a
Optimal shielding of low frequency fields
(2004) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 23 (1), pp. 173-186. Cited 5 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-1442313329&partnerID=40&md5=b1b49ce9c2f270427230fc1b10882297
AFFILIATIONS: Dipto. di Ing. Elettrica Industriale, Politecnico di Torino, Turin, Italy;
Dipartimento di Elettronica, Politecnico di Milano, Milan, Italy
ABSTRACT: Shielding of electromagnetic low frequency field can be performed by means of conductive sheets. These sheets have a thickness which is usually two or three orders of magnitude lower than their other dimensions, thus their effects must be modeled by means of special numerical techniques. In this paper, two integral formulations for the analysis of conductive shields are presented: one is two-dimensional and is based on a multiconductor system, while the other, three-dimensional, is based on a finite formulation of electromagnetic fields. Once these analysis tools have been introduced, this paper presents the study of different shielding systems and a problem of optimal exploitation of conductive material.
AUTHOR KEYWORDS: Electromagnetism; Optimization techniques
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bottauscio, O.a , Manzin, A.a , Canova, A.b , Chiampi, M.b , Gruosso, G.c , Repetto, M.b
Field and circuit approaches for diffusion phenomena in magnetic cores
(2004) IEEE Transactions on Magnetics, 40 (2 II), pp. 1322-1325. Cited 13 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-2342521428&partnerID=40&md5=a7986b20b2e413c08eac26891a0d030d
AFFILIATIONS: Ist. Elettrotecn. Naz. Galileo F., I-10135 Torino, Italy;
Dipto. Ingegneria Elet. Industriale, Politecnico di Torino, I-10129 Torino, Italy;
Dipartimento di Elettronica, Politecnico di Milano, 20133 Milano, Italy
ABSTRACT: This paper presents two approaches for nonlinear dynamic modeling of voltage-driven magnetic circuits. The field approach is based on a finite-element method; in two-dimensional laminated cores, an in-plane magnetic analysis is coupled with a one-dimensional eddy current solution across lamination thickness. The lumped parameter approach subdivides the magnetic core in flux tubes according to geometrical symmetries and solves the coupled electric and magnetic circuits. The two methods are applied to the analysis of magnetic cores and comparisons between them, and experimental data are performed and discussed.
AUTHOR KEYWORDS: Eddy currents; Finite-element method (FEM) analysis; Magnetic circuits
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Canova, A.a , Gruosso, G.b , Repetto, M.a
Magnetic Design Optimization and Objective Function Approximation
(2003) IEEE Transactions on Magnetics, 39 (5 I), pp. 2154-2162. Cited 20 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-0141918459&partnerID=40&md5=1dc904b33bb9287e965a9030ea57f4f8
AFFILIATIONS: Dipto. Ingegneria Elettrica I., Politecnico di Torino, 10129 Torino, Italy;
Dipartimento di Elettronica, Politecnico di Milano, 20133 Milano, Italy
ABSTRACT: This paper addresses the problem of optimizing a device by using an interpolation of the objective function. Optimization by means of stochastic methods can explore the objective function and give reliable indications on its global extrema, but the number of function calls can be unacceptably large when numerically evaluated functions are used. An optimization procedure applied not directly on the objective function but on its interpolation can significantly reduce the cost of the optimization. An efficient coupling between interpolation technique and optimization method is needed both to explore features of the optimization algorithm and to exploit advantages of the interpolation. This paper analyzes the performance of a multiquadric interpolation procedure on analytical functions and on finite-element evaluations.
AUTHOR KEYWORDS: Genetic algorithm; Interpolation of objective function; Optimization; Response surface methodology
DOCUMENT TYPE: Article
SOURCE: Scopus

Canova, A.a , Gruosso, G.b , Repetto, M.a
Integral methods for analysis and design of low-frequency conductive shields
(2003) IEEE Transactions on Magnetics, 39 (4 II), pp. 2009-2017. Cited 24 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-0042766773&partnerID=40&md5=66966b4abc27682c35e98841eda81bb9
AFFILIATIONS: Dipto. di Ing. Elettrica Industriale, Politecnico di Torino, I-10129 Torino, Italy;
Dipartimento di Elettronica, Politecnico di Milano, I-20133 Milan, Italy
ABSTRACT: This paper presents and compares two different approaches to the analysis and design of nonferrous shields for extremely low-frequency magnetic fields. The first method is based on a circuital approach where the shield is modeled by a set of conductors coupled with each other by a matrix of self and mutual inductances. The second technique is based on an algebraic formulation of electromagnetic fields and adapted by means of integral equations to the analysis of thin conductive sheets. The paper shows the accuracy of the two methods for calculating induced current density inside the shield and for evaluating magnetic flux density in the shielded region.
AUTHOR KEYWORDS: Conductive shielding; Extremely low frequency; Finite formulation of electromagnetic fields; Thin conductor
DOCUMENT TYPE: Article
SOURCE: Scopus

Canova, A., Gruosso, G., Repetto, M.
Synthesis of linear actuators
(2001) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 20 (3), pp. 713-723. Cited 5 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-0035788004&partnerID=40&md5=ff9b7ac405ae4d5525743df63fff6006
AFFILIATIONS: Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, Torino, Italy
ABSTRACT: The synthesis of electro-mecliank actuators is formulated as a constrained optimization problem tvliere some performance fumtion ofthe device is to be met, subject to the satisfaction of some constraints about its dimensions and supply conditions. The optimization problem is tackled by means of a genetic algorithm coupled to a multi-objective definition of the objective function tliat merge together objectives and constraints in one single scalar objective function. A fast magnetic analysis tool lias been developed so tliat the computational cost ofthe genetic optimization run is acceptable. Some results about the synthesis of a tubular linear motor in tivo sizes are presented and discussed. © MCB University Press,.
AUTHOR KEYWORDS: Actuators; Genetic algorithms; Optimization
DOCUMENT TYPE: Article
SOURCE: Scopus

Bianchi, N.a , Canova, A.b , Gruosso, G.a , Repetto, M.b , Tonel, F.a
Analytical and finite element design optimisation of a tubular linear IPM motor
(2001) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 20 (3), pp. 777-795. Cited 10 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-0035787626&partnerID=40&md5=75fb2ed3de234311f65e72b2afb3b9a4
AFFILIATIONS: Department of Electrical Engineering, University of Padova, Padova, Italy;
Department of Electrical and Industrial Engineering, Politechnic of Torino, Torino, Italy
ABSTRACT: The optimisation of a tubular linear motor with interior permanent magnets is described. For a rapid design the whole process is divided in three parts: an analytical approach for the a preliminary investigation, a parametric analysis by means of a finite element method and an optimisation. The obtained results show that the adopted optimisation process is efficient for rapid and effective optimisation of the tubular linear motor. © MCB University Press,.
AUTHOR KEYWORDS: Design; Finite ekment; Linear motors; Optimisation
DOCUMENT TYPE: Article
SOURCE: ScopusBizzarri, F.a , Brambilla, A.a , Ferrara, V.b , Gruosso, G.a , Storti-Gajani, G.a , Vigano, L.c
Efficiency improvement of partially shaded photovoltaic panels
(2013) 2013 European Conference on Circuit Theory and Design, ECCTD 2013 – Proceedings, art. no. 6662254, .
http://www.scopus.com/inward/record.url?eid=2-s2.0-84892632829&partnerID=40&md5=ce7a32db02eaf845e1fe3882019b158c
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, p.za. Leonardo da Vinci, n. 32, I20133 Milan, Italy;
Pegasus Microdesign, via Gilera 110, Arcore, Italy;
EU Energy, via Salvo D’Acquisto 39, I20059 Concorezzo (MI), Italy
ABSTRACT: Layouts of domestic photovoltaic solar plants can be problematic due to obstacles that shade panels. This limits the total available area and, if not adequately considered, can deeply affect the efficiency of the plant. In this paper, a circuit that recovers generated power efficiency when a small number of cells of a panel are partially or totally shaded is proposed. This circuit is constituted by DC/DC converters that are connected in parallel to cells and that balance power generation. This solution is borrowed by architectures used to balance charge/discharge of lithium ion batteries. Simulation results and experimental measurements performed on a prototype version of the circuit are reported and described together with its advantages and drawbacks. © 2013 TU Dresden.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bozzi, S.a , Miquel, A.M.a , Scarpa, F.a , Antonini, A.b , Archetti, R.b , Passoni, G.a , Gruosso, G.a
Wave energy production in Italian offshore: Preliminary design of a point absorber with tubular linear generator
(2013) 4th International Conference on Clean Electrical Power: Renewable Energy Resources Impact, ICCEP 2013, art. no. 6586990, pp. 203-208.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84884624219&partnerID=40&md5=33e13ef3e3ad6a9b90c7cdb8893dea8c
AFFILIATIONS: Department of Electronics, Information Science, and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy;
Department of Civil, Environmental and Materials Engineering, University of Bologna, Viale Risorgimento 2, 40136, Bologna, Italy
ABSTRACT: The paper presents the preliminary design and modelling of a point absorber wave energy converter consisting of a floating buoy connected to a tubular linear generator fixed at the seabed. The behaviour of the device is described by the equation of motion of a single body system restricted to vertical motion. The model of the coupled buoy-generator system is used to simulate the behaviour of the wave energy converter under regular waves of different heights and periods. Then the electricity production of an hypothetical installation off the Alghero coast is estimated. The results show that the device capacity factor at the study site is around 15%. This is a very promising value considering that the studied device has not been specifically optimized for the Alghero wave climate. The work suggests that the presented technology could be very attractive for the Italian offshore. © 2013 IEEE.
AUTHOR KEYWORDS: Italian offshore; linear tubular generator; point absorber; wave energy
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bizzarri, F., Brambilla, A., Gruosso, G., Gajani, G.S.
Time domain probe insertion to find steady state of strongly nonlinear high-Q oscillators
(2013) Proceedings – IEEE International Symposium on Circuits and Systems, art. no. 6572229, pp. 1865-1868.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84883377528&partnerID=40&md5=0f70d04183486b958ea0836d3361b8fd
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, P.za. Leonardo da Vinci, n. 32, I20133 Milan, Italy
ABSTRACT: Probe insertion is traditionally used in the frequency domain to increase robustness of the harmonic balance method and avoid the DC degenerate solution. This technique evidences several good properties, for instance when simulating oscillators that are based on high quality factor resonators or AC coupled ones. In this paper the probe insertion technique is extended to the time domain, allowing the application of the shooting method to a wider class of circuits including for example crystal oscillators. Time domain methods, such as shooting, are superior in the simulation of strongly nonlinear, and, thanks to a recent extention, mixed analog/digital circuits. Moreover, time domain probe insertion can be used to find multiple steady state solutions and check their stability properties, without the need to compute the eigenvalues of the monodromy matrix. © 2013 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bizzarri, F.a , Brambilla, A.a , Gruosso, G.a , Guardiani, C.b , Sangiovanni Vincentelli, A.c , Storti Gajani, G.a
Modeling and estimating yield and efficiency of photovoltaic solar parks
(2013) Proceedings of the IEEE International Conference on Industrial Technology, art. no. 6505763, pp. 734-739. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84877630047&partnerID=40&md5=e438e98448852a3bd789ef27e5ecf6d0
AFFILIATIONS: Politecnico di Milano, DEI, p.za. Leonardo da Vinci, n. 32, I20133 Milano, Italy;
Renience Srl, v.le G. Marconi 52, Desenzano del Garda, Italy;
Dep. of Electrical Engineering and Computer Science, University of California – Berkeley, Berkeley, CA, United States
ABSTRACT: Subsidy reduction and the increased importance of photovoltaic energy generation have triggered the need to develop accurate approaches to measure, estimate and possibly forecast energy production with the goal of enabling early detection and diagnosis of parametric faults before they become catastrophic and lead to partial or full shut down of the plant. Moreover the ability of accurately predicting the energy output of a photovoltaic plant is becoming increasingly important to operate efficiently the existing power grid infrastructure that has difficulties with intermittent, unpredictable power sources. In this paper a new model of photovoltaic solar parks designed to estimate efficiency, predict energy production and enable early fault detection is presented. The proposed model is based on an equivalent electro-thermal model of the PhotoVoltaic (PV) cell, which takes as input the irradiance, ambient temperature and wind speed measured by existing sensors and data-logging equipment used in most solar PV parks. The proposed model is demonstrated to accurately predict the performance of real-life MW scale plants. By directly comparing predicted vs. actual energy production, it also allows easy and early identification and diagnose of malfunctions and efficiency drops of PV systems. © 2013 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bizzarri, F., Brambilla, A., Gruosso, G., Gajani, G.
Probe based shooting method to find stable and unstable limit cycles of strongly nonlinear high-Q oscillators
(2013) IEEE Transactions on Circuits and Systems I: Regular Papers, 60 (7), art. no. 6410373, pp. 1870-1880. Cited 2 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84880052193&partnerID=40&md5=c093d792ee40e8188e810018abeaf0ba
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, I20133 Milano, Italy
ABSTRACT: Probe insertion technique is considered as an exclusively frequency domain approach. It has been developed to increase robustness of the harmonic balance method, when simulating autonomous circuits to avoid the dc degenerate solution. This technique evidences several good properties, for instance when simulating oscillators either employing high quality factor resonators or ac coupled ones. In this paper the probe insertion technique is extended to the time domain. This allows the application of the shooting method to a wider class of circuits including for example crystal oscillators. The inherent superiority of the shooting method to simulate strongly nonlinear circuits and its recent reliable extension to mixed analog/digital ones outperforms the potentiality of the harmonic balance method. Furthermore, this time domain probe insertion technique is exploited to find possible multiple steady state solutions and efficiently check stability properties, thus avoiding to compute the eigenvalues of the monodromy matrix. © 2004-2012 IEEE.
AUTHOR KEYWORDS: Crystal oscillators; multiple steady state solutions; probe technique; shooting method
DOCUMENT TYPE: Article
SOURCE: Scopus

Bizzarri, F., Bongiorno, M., Brambilla, A., Gruosso, G., Gajani, G.S.
Model of photovoltaic power plants for performance analysis and production forecast
(2013) IEEE Transactions on Sustainable Energy, 4 (2), art. no. 6324407, pp. 278-285. Cited 2 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84875689995&partnerID=40&md5=5fdfc52966578aa517371f0a85970223
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e Informazione, I20133 Milano, Italy
ABSTRACT: A photovoltaic (PV) plant model is presented. It is based on a detailed electrothermal description of the panels forming strings that, in turn, form the power plant. It accounts for environmental working conditions, such as temperature and wind speed, and specific plant configuration, such as plant topology and power losses due to interconnections. The input variables of the model are the ambient temperature, irradiance, and wind speed. The model derives the working temperature of the panel taking into account also the power conversion performed by the panel; the electrical operating point is determined by simulating the actions done by the maximum power point tracker that operates at plant level. This model has been tested using a large database of experimental data from industrial PV plants characterized by power levels ranging from 250 kW to 1 MW. As shown, the model is capable to predict power production when ‘fed’ by forecast irradiance, ambient temperature, and wind speed data. © 2010-2012 IEEE.
AUTHOR KEYWORDS: Electrothermal macro-models; maximum power point tracker (MPPT); photovoltaic (PV) power plants; solar panels
DOCUMENT TYPE: Article
SOURCE: Scopus

Pisano, M., Bizzarri, F., Brambilla, A., Gruosso, G., Gajani, G.S.
Micro-inverter for solar power generation
(2012) SPEEDAM 2012 – 21st International Symposium on Power Electronics, Electrical Drives, Automation and Motion, art. no. 6264547, pp. 109-113. Cited 5 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84866923518&partnerID=40&md5=ca1fef5a20b3c32365db28daa0354809
AFFILIATIONS: Politecnico di Milano, DEI, p.za Leonardo da Vinci, 32, I20133 Milano, Italy
ABSTRACT: A micro-inverter that takes as input the DC power generated by a solar panel (about 250W) and delivers it directly as AC power to the mains line is presented. The micro-inverter has been designed with discrete components, as it is common practice, since there are no silicon technologies that can be used to integrate the complete circuit and the passive components. The proposed micro-inverter has been extensively simulated and is currently under realisation. The obtained conversion efficiency is greater than 95% and the total harmonic distortion at the output is less than 0.4%. © 2012 IEEE.
AUTHOR KEYWORDS: circuit simulation; DC/AC converter; hybrid systems; microinverter; shooting method; solar power generation; steady state methods
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bizzarri, F.a , Brambilla, A.a , Gruosso, G.a , Gajani, G.S.a , Ferrando, E.b
ADDA: Almost direct drive architecture for solar high power electrical propulsion in new generation spacecrafts
(2012) ISCAS 2012 – 2012 IEEE International Symposium on Circuits and Systems, art. no. 6271746, pp. 2271-2274. Cited 3 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84866359482&partnerID=40&md5=d914adc8ca2f2c7e53093f8ccf772989
AFFILIATIONS: Politecnico di Milano, DEI, p.za Leonardo da Vinci, 32, 120133, Milano, Italy;
Selex Galileo, viale Europa, 120014, Nerviano, Italy
ABSTRACT: This paper proposes a novel electrical power system architecture capable to efficiently transfer energy from a solar generator to high power electric thrusters of a spacecraft. The architecture is based on a maximum power point tracker that acts on a DC/DC converter connected between a subsection of the solar generator and the thrusters. The other sections of the solar generator, that deliver most of the total power, are directly connected to the thrusters. The novelty of the proposed architecture is that the maximum power point tracker is always operating and, while conditioning only a fraction of the total power, is able to transfer to the thrusters an amount of power greater than the handled one. ©2012 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bizzarri, F.a , Callegarit, S.b , Gruosso, G.a
Towards a nearly optimal synthesis of power bridge commands in the driving of AC motors
(2012) ISCAS 2012 – 2012 IEEE International Symposium on Circuits and Systems, art. no. 6271704, pp. 2119-2122. Cited 3 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84866389256&partnerID=40&md5=868231f7962f9b513cda153fd61a2e2f
AFFILIATIONS: Polytechnic of Milan, DEI, Italy;
University of Bologna, ARCES/DEIS, Italy
ABSTRACT: The synthesis of low depth command streams for power bridges is considered, with regards to drives for ac motors. Focus is on the exploitation of the degrees of freedom still available once the command rate is set. Using a nonlinear motor model, different options are evaluated up to the mechanical output. Options such as Delta Sigma Modulation (δσM) and Pulse Width Modulation (PWM) are associated to tuples of merit factors defining points in a performance space. Standard ASM is shown to favor perceived drive quality, while PWM helps keeping the switching rate low. Interpreting both PWM and δσM as heuristics for Pulse Density Modulation (PDM), it is shown that ASM may offer some commonly unexploited forms of tuning and may lead to a more flexible choice of placement on the performance space. © 2012 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
MTFS: Mixed time-frequency method for the steady-state analysis of almost-periodic nonlinear circuits
(2012) IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 31 (9), art. no. 6269967, pp. 1346-1355.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84865310916&partnerID=40&md5=bdc2fa1f2f1ef7a279b7e4761785eecd
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milan I20122, Italy
ABSTRACT: Periodic circuits driven by multitone signals are still a challenging simulation problem despite several numerical methods being presented in the literature. In this paper, a mixed time-frequency method for the solution of this problem and suitable for both autonomous and nonautonomous circuits is presented. The method is based on an extension of the envelope following method, which allows us to reduce the number of unknowns involved in the steady-state problem with respect to previous mixed time-frequency approaches, and a suitable reformulation of the periodicity constraint that allows us to obtain a significant acceleration in the determination of the solution by reducing the time interval along which the envelope analysis must be performed. The method is first presented for nonautonomous circuits and then extended to autonomous ones. © 2012 IEEE.
AUTHOR KEYWORDS: Envelope analysis; mixed frequency-time domain methods; steady-state analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Mussetta, M.a , Shadmehr, H.a , Grimaccia, F.a , Pirisi, A.a , Gruosso, G.b , Zich, R.E.a
Power transfer optimization of wireless energy harvesting system
(2012) IET Conference Publications, 2012 (592 CP), pp. D64.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84864652086&partnerID=40&md5=a5ce4b2edee0fdb6973ac2a81351a025
AFFILIATIONS: Politecnico di Milano, Dipartimento di Energia, Via La Masa 34, 20156 Milano, Italy;
Politecnico di Milano, Dipartimento di Elettronica e dell’Informazione, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
ABSTRACT: This paper will present a novel approach to the design of wireless energy transfer devices, by means of a recently developed evolutionary optimization method. This approach is well suited in order to increase the transfer efficiency and the robustness of the coupling, with the aim of minimizing the average power loss.
AUTHOR KEYWORDS: Biomedical applications; Energy harvesting; Fractal antenna; Optimization; Wireless power transfer
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Gruosso, G.a , Bizzarri, F.a , Storti Gajani, G.a , Brambilla, A.a , Ferrando, E.b
Design and simulation of a power management unit in a solar based electric propulsion system
(2012) IET Conference Publications, 2012 (592 CP), pp. P240. Cited 4 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84864712251&partnerID=40&md5=0445c4359c196cd7de0733e605f1bb5c
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e Informazione, p.zza L. da Vinci 32, I20133 – Milano, Italy;
SELEX Galileo S.p.A, Via Albert Einstein 35, 50013 Campi Bisenzio (FI), Italy
ABSTRACT: The aim of this paper is to compare different architectures for a power system that supplies electrical thrusters for future space exploration missions. The main goal of these architectures is the maximization of the power extracted from the solar arrays in all operational situations and this is possible only by using peak power tracking algorithms. This limits the choice of architectures only to those including some form of peak power tracking algorithms.
AUTHOR KEYWORDS: Power management; Solar array; Space propulsion
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Pirisi, A.b , Mussetta, M.b , Grimaccia, F.b , Caputo, D.b , Gruosso, G.a , Zich, R.E.b
An innovative device for traffic energy harvesting
(2012) IET Conference Publications, 2012 (592 CP), pp. D53.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84864722801&partnerID=40&md5=69a588ab5a56d1881c54eb45d2ac6443
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e dell’Informazione, Piazza Leonardo da Vinci 32, 20133 Milano, Italy;
Politecnico di Milano, Dipartimento di Energia, Via La Masa 34, 20156 Milano, Italy
ABSTRACT: In recent years the increase of massive connections of renewable systems to power grid has highlighted the need to address stability issues with ad-hoc techniques. On the other side, the complexity of electronic devices requires an integrated approach for the different layers of the system, especially in terms of power quality. This task is often supported by advanced soft computing techniques that can be applied by engineers to several device model and used with optimization process, in order to find out the best design improving the system performance and the industrial electronics applications. This approach promises to give new impulse to research on renewable systems and, especially in the last five years, on the so called Energy Harvesting Devices (EHDs). In this paper an innovative speed bumper for energy harvesting from traffic activities is presented. Energy is converted by means of a suitably designed Tubular Permanent Magnet-Linear Generator (TPM-LiG).
AUTHOR KEYWORDS: Energy harvesting device; Linear generator
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Ferrando, E.a , Croci, L.a , Damonte, G.a , Hazan, D.a , Riva, S.a , Romani, R.a , Casaregola, C.b , Brambilla, A.c , Gruosso, G.c , Gajani, G.S.c , Blott, R.d , Battocchio, L.e , Steiner, M.f , Tuissi, A.g , Casati, R.g , Chiarelli, M.h
Study results on a solar electric power system for High Power Electric Propulsion (HiPER) applications
(2011) 62nd International Astronautical Congress 2011, IAC 2011, 9, pp. 7551-7565. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-84864095423&partnerID=40&md5=f58b62dddb3a9f464b69a86a440cf96d
AFFILIATIONS: Selex Galileo, Viale Europa, 20014 Nerviano- MI, Italy;
ALTA S.p.A., Via A. Gherardesca,5, 56121 Pisa, Italy;
Politecnico di Milano, Piazza Leonardo Da Vinci 32, 20133 Milano, Italy;
Space Enterprise Partnerships, Bennetts, Eastergate Lane, Eastergate, Chichester, West Sussex PO20 3SJ, United Kingdom;
AERO SEKUR S.p.A., Via Delle Valli 46, 04011 Aprilia (LT), Italy;
Fraunhofer-Institut für Solare Energiesysteme ISE, Heidenhofstraße 2, 79110 Freiburg, Germany;
Consiglio Nazionale Delle Ricerche, Istituto Per l’Energetica e le Interfasi (CNR-IENI), Corso Promessi Sposi, 29, 23900 LECCO, Italy;
Dipartimento di Ingegneria Aerospaziale, Università di Pisa, Via G. Caruso 8, 56122 Pisa, Italy
ABSTRACT: The aim of this study is, on top of the investigation of an overall PMAD system capable to fulfil the requirements of both solar and nuclear energy sources, to define a solar based power system able to feed high power electric thrusters. This kind of propulsion system could play a very important role in future space exploration programmes by enabling more affordable and sustainable space-to-space missions. HiPER is a project partly funded by the EU aimed at laying the technical and programmatic foundations for the development of technologies to fulfil these future needs. The abstract presents results of development and prototyping of solar generation technologies and gives indications on the optimal PMAD architectures. The power demand of next generation spacecraft will overcome the limits of existing state of the art solar generation systems. Today the multi panel deployable solar array is the most common system utilized for medium and high power applications. Its ability to provide accommodation for power growth up to tens of kW), high reliability, competitive weight and low cost, lead to world wide success but we need something more. Light concentration techniques, thin solar cells and light/flexible substrates are going towards this direction. Starting from our previous experience in lightweight photovoltaic systems, we all initiated the development activities. The main topics addressed in this study are: light concentration (up to 10 times the nominal flux) system design, inflatable substrate and flexible electrical network structural design, prototyping and verification; The solar cell trades started from the very latest achievements in crystalline solar cells. Based on that, a component suitable for light concentration has been identified. This component has been integrated on top of a flexible structure in combination with the concentrating lenses and with an innovative “smart” deployment mechanic based, also, on Shape Memory Alloys (SMA) performances. The PMAD is a critical aspect of the whole system design which can undermine all the other technical advances. A direct drive approach is the most suitable solution and an architecture based on solar DC voltage level of about 300V and a current level of about 800 A has been extensively simulated. Of course there are risks associated with the operation at high current and voltage and this are mainly related to coronal discharge effects. The scope of the present study is to define generic mitigation strategy for making a more precise assessment for the total system mass estimate.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
A probe-based harmonic balance method to simulate coupled oscillators
(2011) IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 30 (7), art. no. 5875987, pp. 960-971.
http://www.scopus.com/inward/record.url?eid=2-s2.0-79959274555&partnerID=40&md5=9ccd93390b0cb0cb1bad6a95ae95bdac
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, Piazza Leonardo da Vinci, Milano I-20133, Italy
ABSTRACT: The probe-based harmonic balance (HB) method is a well-known and largely used tool to compute the steady state behavior of autonomous circuits (oscillators). In this paper, the method is extended to analyze coupled oscillators, where the working frequencies and conditions, i.e., pulling and locking modes, have great relevance. It is shown that probe insertion can be considered as a specific matrix-bordering technique applied to the Jacobian matrix of the HB method. It transforms the original coupled autonomous system in a non-autonomous one, forcing the circuit to lock to the probes themselves. In this context, a novel approach to find the steady state solution is introduced. This approach exploits the properties of the power exchanged among the probes and the coupled oscillators. Possibly, more than one steady state solution with the oscillators working in pulling or locking modes can be found. © 2011 IEEE.
AUTHOR KEYWORDS: Coupled oscillators; harmonic balance; probe insertion method; pulling-locking modes
DOCUMENT TYPE: Article
SOURCE: Scopus

Gruosso, G.a , Mussetta, M.b c , Zich, R.E.b
Optimization of an antenna for wireless energy transfer
(2011) Proceedings of the 5th European Conference on Antennas and Propagation, EUCAP 2011, art. no. 5781720, pp. 1208-1209. Cited 4 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-79959636268&partnerID=40&md5=8a034f9b224fc25bd120606f20f6da19
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e dell’Informazione, via Ponzio, 34/5, 20133 Milano, Italy;
Politecnico di Milano, Dipartimento di Energia, Via La Masa, 34, 20156 Milano, Italy;
Politecnico di Torino, Dipartimento di Elettronica, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy
ABSTRACT: Inductive links is the most popular solution to wirelessly send power and data from an external transmitter to implantable biomedical device. This paper proposes the optimized design of a wireless energy transfer devices, by means of an evolutionary optimization method. This procedure is developed in order to increase the transfer efficiency and the robustness of the coupling, with the aim of minimizing the average power loss. © 2011 EurAAP.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Pirisi, A.a , Mussetta, M.a b , Gruosso, G.c , Zich, R.E.a
Automated TPM-LiG modeling for WSN subsystems in marine environment
(2010) Proceedings – 2010 12th International Conference on Electromagnetics in Advanced Applications, ICEAA’10, art. no. 5651174, pp. 733-736. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-78651317112&partnerID=40&md5=d28771a8437dd989f3ca272ab68c9934
AFFILIATIONS: Politecnico di Milano, Dipartimento di Energia, Sez. Elettrica, Via La Masa 34, 20156 Milano, Italy;
Politecnico di Torino, Dipartimento di Elettronica, C.so Duca degli Abruzzi 24, 10129 Torino, Italy;
Politecnico di Milano, Dipartimento di Elettronica e dell’Informazione, via Ponzio 34/5, 20133 Milano, Italy
ABSTRACT: With the appreciating of problems related to the environmental impact evaluation of human activities, wireless sensor networks (WSNs) are emerging as suitable monitoring systems for large geographical areas, fixing new challenges in many scientific areas such as computer science, wireless communication and energy harvesting. In recent years tubular permanent magnet linear generators (TPM-LiG) have been proposed in several marine applications as a well-suited technology for power generation such as power buoys. In this work an automated soft-computing approach is presented in order to provide an optimized electromagnetic model of TPM-LiG. A prototype of tubular generator was set up and measures provided, to a large extent, a first validation of the predictive model used in the proposed automated approach. ©2010 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Pirisi, A.a , Mussetta, M.a b , Gruosso, G.c , Zich, R.E.a
Optimization of a linear generator for sea-wave energy conversion by means of a hybrid evolutionary algorithm
(2010) 2010 IEEE World Congress on Computational Intelligence, WCCI 2010 – 2010 IEEE Congress on Evolutionary Computation, CEC 2010, art. no. 5586370, . Cited 10 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-79959436420&partnerID=40&md5=a2dcc3f14b1a622b0ac9896b9aa6998d
AFFILIATIONS: Politecnico di Milano, Dipartimento di Energia, Via La Masa, 34, 20156 Milano, Italy;
Politecnico di Torino, Dipartimento di Elettronica, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy;
Politecnico di Milano, Dipartimento di Elettronica, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy
ABSTRACT: In this paper the optimization of a Tubular Permanent Magnet-Linear Generator (TPM-LiG) for energy generation is presented. The application is related to the sea wave energy generation for small sensorized buoy. The optimization process is developed by means of an hybrid evolutionary algorithm widely presented in the paper. The advantage of this algorithm is in the wide exploration of the variables space and in the effective exploitation of the fitness function. The algorithm has been tested on a benchmark case and then applied to the optimization of the here considered device. © 2010 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Pirisi, A.a , Mussetta, M.a b , Gruosso, G.c , Zich, R.E.a
Bio-inspired optimization techniques for wireless energy transfer
(2010) Proceedings – 2010 12th International Conference on Electromagnetics in Advanced Applications, ICEAA’10, art. no. 5651102, pp. 731-732. Cited 3 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-78651273552&partnerID=40&md5=a676abd70efe65d3880fae8fa65d27d6
AFFILIATIONS: Politecnico di Milano, Dipartimento di Energia, Sez. Elettrica, Via La Masa 34, 20156 Milano, Italy;
Politecnico di Torino, Dipartimento di Elettronica, C.so Duca degli Abruzzi 24, 10129 Torino, Italy;
Politecnico di Milano, Dipartimento di Elettronica e dell’Informazione, via Ponzio 34/5, 20133 Milano, Italy
ABSTRACT: This paper provides a novel approach to the design of wireless energy transfer devices, by means of an hybrid evolutionary optimization method, the recently developed Genetical Swarm Optimization. This approach is well suited in order to increase the transfer efficiency and the robustness of the coupling, with the aim of minimizing the average power loss. ©2010 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Rocco, P., Gruosso, G., Magnani, G.
Mechatronic model of oscillations in hybrid stepper motors
(2010) IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM, art. no. 5695852, pp. 726-731. Cited 2 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-79951642886&partnerID=40&md5=90a6f68f2b13f6e245a21de64d0d70a2
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e Informazione, Piazza L. da Vinci 32, 20133 Milano, Italy
ABSTRACT: Hybrid stepper motors combine the features of permanent magnet and variable reluctance motors, which makes them an attractive solution for a variety of low-cost applications. Oscillations in the phase current and in the motor position may however arise between two consecutive steps. This paper develops a model of the system, whose linearization yields closed form analytical expressions of the parameters (natural frequency and damping coefficient) characterizing such oscillations. A detailed simulation model of the system, including discontinuous effects of PWM amplification, is developed as well and validated with experimental data. The accuracy of the expression found for the oscillation parameters is also validated. © 2010 IEEE.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Pirisi, A.a , Mussetta, M.a b , Gruosso, G.c , Zich, R.E.a
An optimized three phase TPM-LiG for marine applications
(2010) SPEEDAM 2010 – International Symposium on Power Electronics, Electrical Drives, Automation and Motion, art. no. 5542211, pp. 1712-1717. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-77956574581&partnerID=40&md5=1c772f41ccf51cf2215f90951ea61772
AFFILIATIONS: Politecnico di Milano, Dipartimento di Energia, Via La Masa, 34, 20156 Milano, Italy;
Politecnico di Torino, Dipartimento di Elettronica, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy;
Politecnico di Milano, Dipartimento di Elettronica, Piazza Leonardo da Vinci, 32, 20133 Milano, Italy
ABSTRACT: In recent years linear generators have been proposed in several marine applications as a well-suited technology for power generation such as power buoys. Those kind of buoys could be used as large-scale devices in power plants and as small-size devices in electronic supply as well. In this work a numerical model of a three phase tubular permanent magnet linear generator is integrated with a Genetical Swarm Optimization algorithm in order to provide a first optimization for electronic applications. Numerical results have been reported and discussed and a generator prototype has been tested on a test bed in order to validate the predicted perfomances. © 2010 IEEE.
AUTHOR KEYWORDS: Optimization; Optimization algorithm; Tubular linear generator; Wave energy
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Brambilla, A., Gruosso, G., Redaelli, M., Gajani, G.S.
Periodic noise analysis of electric circuits: Artifacts, singularities and a numerical method
(2010) International Journal of Circuit Theory and Applications, 38 (7), pp. 689-708. Cited 9 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-77956375342&partnerID=40&md5=b1ce7f05d0c0226dc06d9b41b56e382b
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e Informazione, p.za Leonardo da Vinci, 32, I-20133 Milano, Italy
ABSTRACT: In this paper it is shown that a numerical method largely adopted for the simulation of noise in autonomous circuits is affected by singularities that manifest when the frequency at which the noise analysis is carried out approaches a harmonic of the autonomous circuit. The resulting noise power spectral density (PSD) is thus characterized by spurious spikes. The presence of these singularities is for the first time justified from an analytical standpoint and their effects are shown by simulating some oscillators, employed as benchmarks. Furthermore, the presented approach justifies the 1/(f s – f)2 shape of the PSD of noise at the output when the fs frequency approaches the f fundamental of a stable oscillator and the 1/| fs – f |3 shape when the effects of flicker noise are manifest. Copyright © 2009 John Wiley & Sons, Ltd.
AUTHOR KEYWORDS: Floquet theory; Noise analysis; Oscillators; Periodic circuits; Periodic noise analysis; Phase noise; Small signal analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
FSSA: Fast steady-state algorithm for the analysis of mixed analog/digital circuits
(2010) IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 29 (4), art. no. 5433754, pp. 528-537. Cited 5 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-77949883388&partnerID=40&md5=93f5d0e1648e037cef7ca65764ebd17e
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milano I20133, Italy
ABSTRACT: The shooting method is largely employed to determine the steady-state working condition of both autonomous and nonautonomous circuits. In general, the conventional shooting method employs the Newton algorithm to estimate a better approximation of the steady-state working condition. The Newton algorithm requires the computation of the Jacobian matrix and this seriously limits the use of the conventional shooting method to solve medium/large scale circuits. In this paper, an approach to efficiently determine the shooting matrix is presented. It is shown that the approach is also adequate to deal with mixed analog/digital circuits. © 2010 IEEE.
AUTHOR KEYWORDS: Leading dynamics; Mixed analog/digital circuits; Shooting method; Steady-state analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
Robust harmonic-probe method for the simulation of oscillators
(2010) IEEE Transactions on Circuits and Systems I: Regular Papers, 57 (9), art. no. 5439844, pp. 2531-2541. Cited 4 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-77957750805&partnerID=40&md5=37c663538b06b68b9ea06e15bc3d6f91
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, 20133 Milano, Italy
ABSTRACT: This paper considers the harmonic balance method (HB) in conjunction with the probe insertion technique. In general, the nonlinear equations modeling the circuit in the frequency domain are solved with the Newton iterative method. It is known that, in many cases, probe insertion in the original circuit shows better convergence properties of the Newton method and therefore of the harmonic balance when simulating autonomous circuits. The probe technique is considered here in detail, and numerical aspects are discussed mainly for what concerns the condition number of the Jacobian matrix related to the Newton method. The probe technique is then improved by exploiting properties of the power exchanged between the probe and the circuit in which it is inserted; moreover, an automatic probe insertion mechanism is detailed. © 2010 IEEE.
AUTHOR KEYWORDS: Frequency-domain simulation; harmonic balance method (HB); injection locking; oscillators; probes
DOCUMENT TYPE: Article
SOURCE: Scopus

Brambilla, A.a , Gruosso, G.a , Redaelli, M.A.a , Gajani, G.S.a , Caviglia, D.D.b
Improved small-signal analysis for circuits working in periodic steady state
(2010) IEEE Transactions on Circuits and Systems I: Regular Papers, 57 (2), art. no. 4806052, pp. 427-437. Cited 20 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-76849086627&partnerID=40&md5=e6ebcb9b4c1ebf3f6f20547fec62d46f
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milano, Italy;
Dipartimento di Biofisica Ed Elettronica, Università di Genova, Genova, Italy
ABSTRACT: This paper considers the formulation of the variational model (VM) of autonomous circuits (oscillators) working in periodic steady-state conditions. The shooting method, which is largely used to compute the solution in the time domain when the VM is forced by a small-signal perturbation, is studied. The proposed analytical approach can be exploited to improve accuracy in the simulation of the effects of noise sources. In particular, we justify from an analytical standpoint the adoption of a suitable periodicity constraint in the shooting method. We exploit the properties of block circulant matrices that naturally arise in the description of the problem. We prove that the frequency of the small-signal perturbation must be different from that of the unperturbed oscillator to avoid inaccuracy of the shooting method due to the existence of singularities in the VM formulation, and derive a method that allows us to get closer to the singularity. © 2006 IEEE.
AUTHOR KEYWORDS: Autonomous circuits; Block circulant matrices; Periodic small-signal analysis; Phase noise; Shooting method; Variational model (VM)
DOCUMENT TYPE: Article
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
Multi-Probe harmonic balance method to simulate coupled oscillators
(2009) 3rd International Conference on Signals, Circuits and Systems, SCS 2009, art. no. 5414185, . Cited 2 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-77951489798&partnerID=40&md5=d42807cf216e0d07e8a22b1c0424e52a
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e Informazione, p.za Leonardo da Vinci, 32, 120133, Milano, Italy
ABSTRACT: In this paper the harmonic balance method is considered in conjunction with the probe insertion technique. In general, the nonlinear equations modeling the circuit in the frequency domain are solved with the Newton iterative method. Conventional probe insertion technique has become popular and implemented in commercial analog simulators, since in many cases it shows better convergence behaviour of the Newton method and, therefore, of the harmonic balance one applied to autonomous circuits. The conventional probe technique, which is based on the insertion of a single probe, is here considered in detail, improved and extended through the insertion of two distinct probes working at two different frequencies with non necessarily an integer ratio. This improved version is exploited to compute the steady state working condition of coupled oscillators that operate in a pulling condition and that can switch to a locking one according to variations of circuit parameters. © 2009 IEEE.
AUTHOR KEYWORDS: Coupled oscillators; Harmonic balance; Probe insertion; Pulling-locking modes
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Pirisi, A.a , Gruosso, G.b , Zich, R.E.a
Novel modeling design of three phase tubular permanent magnet linear generator for marine applications
(2009) POWERENG 2009 – 2nd International Conference on Power Engineering, Energy and Electrical Drives Proceedings, art. no. 4915209, pp. 78-83. Cited 9 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-70349307500&partnerID=40&md5=03de02466f049dd4da096ba16c6f1241
AFFILIATIONS: Politecnico di Milano, Dipartimento di Energia, Italy;
Politecnico di Milano, Dipartimento di Elettronica e dell’ Informazione, Italy
ABSTRACT: In recent years linear generators have been proposed in several marine applications as a well-suited technology for power generation such as power buoys. Those kinds of buoys could be used as large-scale devices in power plants and as small-size devices in electronic supply as well. In this work a three phase tubular permanent magnet linear generator is analyzed to supply electronic devices such as sensorial buoys with energy scavenging. A soft-computing algorithm based on a finite element method has been developed and a parametric approach is presented in order to provide a first optimization for electronic applications. Numerical results have been reported and discussed in detail.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
Determination of floquet exponents for small-signal analysis of nonlinear periodic circuits
(2009) IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 28 (3), art. no. 15, pp. 447-451. Cited 9 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-60749128721&partnerID=40&md5=0c94c7dcd525ed2ca3b68c396fb93833
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, 20133 Milano, Italy
ABSTRACT: This paper describes an approach to determine the Floquet exponents and the related eigenfunctions of linear time-varying circuits, that represent a vehicle to implement the variational model of periodic nonlinear circuits. The Floquet exponents and eigenfunctions allow us to exploit the structure of the analytical solution of the linear time-varying circuit and, as shown, yield an efficient solution. The proposed approach allows the calculation of the Floquet exponents directly and is developed from the harmonic-balance formulation adopted to find the steady-state solution of the nonlinear periodic circuit. © 2006 IEEE.
AUTHOR KEYWORDS: Floquet theory; Harmonic balance (HB); Periodic circuits; Small-signal analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Delinchant, B.a , Gruosso, G.b , Wurtz, F.a
Two levels modeling for the optimization of electromagnetic actuators
(2009) IEEE Transactions on Magnetics, 45 (3), art. no. 4787296, pp. 1724-1727. Cited 7 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-61449268157&partnerID=40&md5=fd7e40078a5308c7dc5eaa7da517090b
AFFILIATIONS: G2ELab Grenoble Electrical Engineering Lab., ENSE3, 38402 Grenoble, France;
Politecnico di Milano, Dipartimento di Elettronica e Informazione, Piazza Leonardo da Vinci, 32-20133 Milano, Italy
ABSTRACT: In this paper, a two-stage modelling, to ensure a good and fast optimization procedure for microdevices, is presented. This methodology is supported by three noncommercial software. The first one is dedicated to analytical modelling of non ferromagnetic electromagnetic devices, the second one is dedicated to numerical modelling of electromagnetic devices, and the last is dedicated to constrained-based optimization. Issues and solutions of such a methodology are highlighted, and illustrated by designing a matrix of actuators for an adaptive optic. © 2006 IEEE.
AUTHOR KEYWORDS: Electromagnetic MEMS; Multilevel modeling; Optimal design
DOCUMENT TYPE: Article
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S.
Determination of floquet exponents for small-signal analysis of nonlinear periodic circuits
(2009) IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, 28 (1), pp. 447-451.
http://www.scopus.com/inward/record.url?eid=2-s2.0-77955179645&partnerID=40&md5=40b9abaa82b3e337b0c1392b038985f3
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, 20133 Milano, Italy
ABSTRACT: This paper describes an approach to determine the Floquet exponents and the related eigenfunctions of linear time-varying circuits, that represent a vehicle to implement the variational model of periodic nonlinear circuits. The Floquet exponents and eigenfunctions allow us to exploit the structure of the analytical solution of the linear time-varying circuit and, as shown, yield an efficient solution. The proposed approach allows the calculation of the Floquet exponents directly and is developed from the harmonic-balance formulation adopted to find the steady-state solution of the nonlinear periodic circuit. © 2009 IEEE.
AUTHOR KEYWORDS: Floquet theory; Harmonic balance (HB); Periodic circuits; Small-signal analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Brambilla, A., Gruosso, G., Gajani, G.S., Redaelli, M.
QR factorisation in the shooting method
(2008) 4th European Conference on Circuits and Systems for Communications, ECCSC ’08, art. no. 4611670, pp. 172-175.
http://www.scopus.com/inward/record.url?eid=2-s2.0-53749095194&partnerID=40&md5=6870c284acabb7ef0539bb391bad2569
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, P.za Leonardo da Vinci, 32, I20133, Milano, Italy
ABSTRACT: Radio frequency (RF) applications in consumer electronics require solid methods for the computation of the steady state behaviour in autonomous and non autonomous circuits. The shooting method (SH) is possibly the most important steady state time domain numerical method currently employed in circuit simulation. We show that SH requires great care in the choice and use of matrix factorization methods. In particular, the advantages of QR over the more standard and widely employed LU method are shown. ©2008 IEEE.
AUTHOR KEYWORDS: Periodic circuits; Qr decomposition; Shooting method; Steady state analysis
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Gruosso, G., Brambilla, A.
Magnetic core model for circuit simulations including losses and hysteresis
(2008) International Journal of Numerical Modelling: Electronic Networks, Devices and Fields, 21 (5), pp. 309-334. Cited 2 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-52449118223&partnerID=40&md5=c18547403ed49555dd71fb2c6905b643
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, p.za Leonardo da Vinci 32, 120133 Milano, Italy
ABSTRACT: This paper presents a magnetic core model that accounts the effects due to nonlinearity, hysteresis and eddy currents. The model is suited to circuit simulation and can be implemented as a subcircuit. To test the proposed implementation the results obtained by simulating a power square wave generator (Royer oscillator) have been compared with measurements on a laboratory prototype. Copyright © 2008 John Wiley & Sons, Ltd.
AUTHOR KEYWORDS: Circuit simulation; Eddy currents; Hysteresis; Magnetic code model
DOCUMENT TYPE: Article
SOURCE: Scopus

Freschi, F.a , Gruosso, G.b , Repetto, M.a
Force computation by hybrid cell method
(2008) IEEE Transactions on Magnetics, 44 (6), art. no. 4526867, pp. 1198-1201. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-44049104078&partnerID=40&md5=93ad61ff28ee98fb07cd4056eaa5fd08
AFFILIATIONS: Dipartimento di Ingegneria Elettrica, Politecnico di Torino, I-10129 Torino, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, I-20133 Milano, Italy
ABSTRACT: Force computation in magnetostatic structures is approached by surface integration of Maxwell stress tensor. Two formulations based on the cell method are presented: the first one with volume discretization and the second one with a hybrid integral scheme. A case with permanent magnets where experimental values of force are available is used as benchmark for comparison of both accuracy and computational cost of the two approaches. © 2008 IEEE.
AUTHOR KEYWORDS: Cell method; Green function; Hybrid formulations; Magnetic forces
DOCUMENT TYPE: Article
SOURCE: Scopus

Alotto, P.a , Gruosso, G.b , Moro, F.a , Repetto, M.c
A boundary integral formulation for eddy current problems based on the cell method
(2008) IEEE Transactions on Magnetics, 44 (6), art. no. 4526789, pp. 770-773. Cited 3 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-44049095019&partnerID=40&md5=a47e47b2e68b5932e9bbe47910234789
AFFILIATIONS: Dipartimento di Ingegneria Elettrica, Università di Padova, 35131 Padova, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, 20133 Milano, Italy;
Dipartimento di Ingegneria Elettrica, Politecnico di Torino, 10129 Torino, Italy
ABSTRACT: A finite formulation for 3-D eddy current problems in unbounded domains is presented. This approach is based on the discrete magnetic vector potential to model conducting regions and on the magnetic scalar potential to model free space. In order to avoid meshing of the air region, integral boundary conditions coupling Dirichlet and Neumann data are used. A numerical strategy based on the Schur complement approach is used in order to improve the convergence properties of the iterative solver. Simulation results show that the proposed approach is both fast and accurate. © 2008 IEEE.
AUTHOR KEYWORDS: Cell method; Eddy current; Hybrid method; Magnetic field; Unbounded domains
DOCUMENT TYPE: Article
SOURCE: Scopus

Alotto, P.a , Gruosso, G.b , Moro, F.a , Repetto, M.c
Three-dimensional eddy current analysis in unbounded domains by a DEM-BEM formulation
(2008) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 27 (2), pp. 460-466.
http://www.scopus.com/inward/record.url?eid=2-s2.0-40549123718&partnerID=40&md5=dce75f1cdad6ce0e84cd34c463490e66
AFFILIATIONS: Dipartimento di Ingegneria Elettrica, Università di Padova, Padova, Italy;
Dipartimento di Elettronica ed Informazione, Politecnico di Milano, Milano, Italy;
Dipartimento di Ingegneria Elettrica, Politecnico di Torino, Torino, Italy
ABSTRACT: Purpose – To propose a novel 3D hybrid approach, based on a discrete formulation of Maxwell equations (the cell method – CM), suitable for solving eddy current problems in unbounded domains. Design/methodology/approach – Field equations for magnetodynamics are expressed directly in algebraic form thanks to the CM. The eddy current problem inside bulk conductors is formulated in terms of discrete modified vector potential, whereas magnetic scalar potential is used in order to model the free space. The CM is coupled to the boundary element method by using a surface boundary operator, which maps the surface magnetic fluxes to the surface magnetic scalar potentials. This leads to a unique set of linear equations to be solved in terms of discrete potentials. The eddy currents in bulk conductors are then obtained from discrete potentials. Findings – It is shown that formulation of hybrid approaches can be simplified by expressing field equations directly in algebraic form without need of weighted residual techniques. An original strategy, based on Green’s formula for the magnetic scalar potential, is proposed in order to couple conducting parts to the exterior domain. Research limitations/implications – Conducting bodies with multiply connected parts cannot be modelled by the proposed approach, since it is based on the magnetic scalar potential. The resulting global matrix is partially dense and non-symmetric; therefore, standard iterative solvers such as GMRES have to be used. Practical implications – The proposed approach can be suitably used for analyzing eddy current problems involving models with high degree of complexity, large air domains and moving parts. These are typical of induction heating processes. Originality/value – This paper proposes a new 3D hybrid approach, based on a discrete formulation of Maxwell equations. A novel coupling strategy relying on integral electromagnetic variables, i.e. magnetic fluxes and magnetic scalar potentials, is devised in order to solve uniquely for eddy currents inside conducting bodies. © Emerald Group Publishing Limited.
AUTHOR KEYWORDS: Eddy currents; Electromagnetic induction; Heat treatment; Magnetic fields
DOCUMENT TYPE: Article
SOURCE: Scopus

Gruosso, G.a , Repetto, M.b
Magnetostatic solution by hybrid technique and fast multipole method
(2008) Physica B: Condensed Matter, 403 (2-3), pp. 368-371. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-37349102636&partnerID=40&md5=54bf62564d64487afb100592affffcd3
AFFILIATIONS: Politecnico di Milano, Dipartimento di Elettronica e Informazione, I-20133 Milano, Italy;
Politecnico di Torino, Dipartimento di Ingegneria Elettrica, C.so Duca Abruzzi 24, I-10129 Torino, Italy
ABSTRACT: The use of fast multipole method (FMM) in the solution of a magnetostatic problem is presented. The magnetostatic solution strategy is based on finite formulation of electromagnetic field coupled with an integral formulation for the definition of boundary conditions on the external surface of the unstructured mesh. Due to the hypothesis of micromagnetic problem, the resulting matrix structure is sparse and integral terms are only on the RHS. Magnetic surface charge is used as source of these integral terms and is localized on the faces between tetrahedra. The computation of the integral terms can be performed by analytical formulas for the near field contributes and by FMM for far field ones. © 2007 Elsevier B.V. All rights reserved.
AUTHOR KEYWORDS: Cell method; Fast multipole method; Hybrid techniques; Micromagnetics
DOCUMENT TYPE: Article
SOURCE: Scopus

Canova, A.a , Freschi, F.a , Repetto, M.a , Gruosso, G.b
Coupling of finite formulation with integral techniques
(2008) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 27 (1), pp. 37-46.
http://www.scopus.com/inward/record.url?eid=2-s2.0-38149000813&partnerID=40&md5=b0a2afdfd3afa11dfc95120424d79e51
AFFILIATIONS: Dipartimento di Ingegneria Elettrica, Politecnico di Torino, Torino, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milano, Italy
ABSTRACT: Purpose: The paper aims to describe the coupling of magnetostatic finite formulation of electromagnetic field with two integral methods. Design/methodology/approach: The first hybrid scheme is based on Green’s function applied to magnetization source while the other one is based on a magnetic scalar potential boundary element method. A comparison of the two techniques is performed on a benchmark case with analytical solution, on a 2D multiply-connected problem and on an industrial case where measurements are available. Findings: The proposed hybrid approaches have proved to be effective techniques to solve open boundary non-linear magnetostatic problems. Similar convergence speed with respect to the number of unknowns is found for both schemes Originality/value: The paper shows the effectiveness of hybrid schemes applied to the finite formulation, assessing their performances on various test cases. © Emerald Group Publishing Limited.
AUTHOR KEYWORDS: Electromagnetic fields; Electromagnetism; Numerical analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Mitolo, M.a b , Gruosso, G.c , Canova, A.d , Tartaglia, M.d
Evaluation of voltage exposures due to AC/DC stray currents
(2007) Conference Record – IAS Annual Meeting (IEEE Industry Applications Society), art. no. 4347984, pp. 1517-1521.
http://www.scopus.com/inward/record.url?eid=2-s2.0-47849126157&partnerID=40&md5=4988ef9da7798df12b3797ac0b8e9740
AFFILIATIONS: IEEE;
Chu and Gassman, 559 Union Ave., Middlesex, NJ 08846, United States;
Dipartimento Elettronica e Informazione, Politecnico di Milano, P.le Leonardo da Vinci, 32, 20133 Milano, Italy;
Dipartimento Ingegneria Elettrica, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy
ABSTRACT: Stray currents leaking from DC and AC electrical installations may flow through buried metal works towards their sources. Such currents may circulate through intentional electrodes, for example dwelling units and railways grounding systems, but also through building and tunnels metal frames, as well as, water and gas utility pipelines. Besides the corrosion phenomena, triggered over the aforementioned metal parts by DC currents, the stray currents may energize these conductive parts, exposing persons to touch voltages. This paper proposes an approach to evaluate the voltage exposure appearing on the aforesaid metal parts, based on the estimation of an appropriate ground-resistance matrix. This matrix, used in conjunction with a system of circuit equations, will yield voltage and current associated to the interfering electrodes. In the case of standard electrode configurations (e.g. spherical, cylindrical, etc.) the evaluation of the above mentioned matrix may be analytically carried out [1]. To take into account complex electrode geometries and/or non-homogeneous soil conditions, numerical elaboration based on the method of the moments [2] will be employed. History cases are presented and discussed. © 2007 IEEE.
AUTHOR KEYWORDS: Earth systems; Electrodes interaction; Method of the moments; Stray current; Touch voltages
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Freschi, F.a , Repetto, M.a , Gruosso, G.b , Maffucci, A.c , Villone, F.c , Zamboni, W.c
Investigation of low-frequency behaviour of two surface integral full-Maxwell formulations
(2007) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 26 (3), pp. 842-858.
http://www.scopus.com/inward/record.url?eid=2-s2.0-34547296543&partnerID=40&md5=f916ee47c0b559ac5700e57fa8377026
AFFILIATIONS: Politecnico di Torino, Torino, Italy;
Politecnico di Milano, Milano, Italy;
EURATOM/ENEA/CREATE Association, DAEIMI, Università Degli Studi di Cassino, Cassino, Italy
ABSTRACT: Purpose – To apply two different integral formulations of full-Maxwell’s equations to the numerical study of interconnects in a low-frequency range and compare the results. Design/methodology/approach – The first approach consists of a surface formulation of the full-Maxwell’s equations in terms of potentials, giving rise to a surface electric field integral equation. The equation, given in a weak form, is solved by using a finite element technique. The solenoidal and non-solenoidal components of the electric current density are separated using the null-pinv decomposition to avoid the low-frequency breakdown. The second model is an extension of partial element equivalent circuit technique to unstructured meshes allowing the use of triangular meshes. Two systems of meshes tied by duality relations are defined on multiconductor systems. The key point in the definition of the equivalent network is to associate the pair primal edge/dual face to a circuit branch. Solution of the resulting electrical network is performed by a modified nodal analysis method and regularization of the outcoming matrix is accomplished by standard techniques based on the addition of suitable resistors. Findings – Both the formulation have a regular behaviour at very low frequency. This is automatically achieved in the first approach by using the null-pinv decomposition. Research limitations/implications – Surface sources of fields. Originality/value – Two different integral formulations of full-Maxwell’s equations for the numerical study of interconnects are compared in terms of low-frequency behaviour. © Emerald Group Publishing Limited.
AUTHOR KEYWORDS: Integral equations; Numerical analysis
DOCUMENT TYPE: Article
SOURCE: Scopus

Canova, A.a , Gruosso, G.b
3D source simulation method for static fields in inhomogeneous media
(2007) International Journal for Numerical Methods in Engineering, 70 (9), pp. 1096-1111.
http://www.scopus.com/inward/record.url?eid=2-s2.0-34249717926&partnerID=40&md5=615562eb0eb022a141fadce54e06f087
AFFILIATIONS: Dipartimento di Ingegneria Elettrica, Politecnico di Torino, c.so Duca Degli Abruzzif 24, Torino I-10129, Italy;
Dipartimento di – Elettronica e Informazione, Politecnico di Milano, p.zza Leonardo da Vinci 32, Milamo I-20133, Italy
ABSTRACT: In this paper, an integral approach based on the source simulation method (SSM) for the solution of three dimensional (3D) static electric fields is presented. This is an extension of the well-known charge simulation method to the electric and current static fields. The formulation allows the solution of 3D electrostatic or static current field problems, where several perfectly conducting bodies (electrodes) are placed in inhomogeneous media. Only electrode surfaces and dielectric interfaces need to be discretized by triangular elements. Matrix coefficients are accurately evaluated by using closed integral forms of 1/r and of grad (1/r). Dirichlet and Neumann conditions can be imposed on the different conducting bodies; in particular, floating potential problem can also be solved. The method of images allows ground plane to be taken into account. The procedure has been applied to several practical cases and it represents an efficient tool for the evaluation of lumped circuit parameters such as capacitances of 3D conducting bodies and ground resistances of grounding system. Copyright © 2006 John Wiley & Sons, Ltd.
AUTHOR KEYWORDS: Capacitance; Charge simulation method; Dielectric; Electrostatic; Grounding system; Static field
DOCUMENT TYPE: Article
SOURCE: Scopus

Lahaye, D.a , Canova, A.b , Gruosso, G.c , Repetto, M.b
Adaptive manifold-mapping using multiquadric interpolation applied to linear actuator design
(2007) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 26 (2), pp. 225-235. Cited 4 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-34147206741&partnerID=40&md5=010328f42e55199833b1b56df3aa0818
AFFILIATIONS: Centrum voor Wiskunde en Informatica (CWI), Amsterdam, Netherlands;
Dipartimento di Ingegneria Elettrica, Politecnico di Torino, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milano, Italy
ABSTRACT: Purpose – This work aims to present a multilevel optimization strategy based on manifold-mapping combined with multiquadric interpolation for the coarse model construction. Design/methodology/approach – In the proposed approach the coarse model is obtained by interpolating the fine model using multiquadrics in a small number of points. As the algorithm iterates the response surface model is improved by enriching the set of interpolation points. Findings – This approach allows to accurately solve the TEAM Workshop Problem 25 using as little as 33 finite element simulations. Furthermore, it allows a robust sizing optimization of a cylindrical voice-coil actuator with seven design variables. Research limitations/implications – Further analysis is required to gain a better understanding of the role that the initial coarse model accuracy plays in the convergence of the algorithm. The proposed model allows to carry out such analysis by varying the number of points included in the initial response surface model. The effect of the trust-region stabilization in the presence of manifolds of equivalent solutions is also a topic of further investigations. Originality/value – Unlike the closely related space-mapping algorithm, the manifold-mapping algorithm is guaranteed to converge to a fine model optimal solution. By combining it with multiquadric response surface models, its applicability is extended to problems for which other kinds of coarse model such as lumped parameter approximations for instance are tedious or impossible to construct. © Emerald Group Publishing Limited.
AUTHOR KEYWORDS: Actuators; Interpolation; Optimization techniques
DOCUMENT TYPE: Article
SOURCE: Scopus

Freschi, F.a , Gruosso, G.b , Repetto, M.a
Unstructured PEEC formulation by dual discretization
(2006) IEEE Microwave and Wireless Components Letters, 16 (10), art. no. 882407, pp. 531-533. Cited 4 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-55149121594&partnerID=40&md5=954dd0155b1acfc66311d7e7b198625c
AFFILIATIONS: Politecnico di Torino, Turin I-10129, Italy;
Politecnico di Milano, Milano 20158, Italy
ABSTRACT: This letter presents a new lumped parameter approach for the solution of the electromagnetic problem of a system of conductors lying in a homogeneous region. By exploiting duality relations between two systems of meshes, an equivalent network of lumped parameters is obtained. This approach is conceptually equivalent to the partial element equivalent circuit formulation but it can overcome the limits imposed by a regular discretization present in its original version. Details about computation of lumped parameters and definition of equivalent network are given. Results obtained on two configurations referenced in the literature are finally discussed © 2001-2012 IEEE.
AUTHOR KEYWORDS: Dual discretization; partial element equivalent circuit (PEEC); unstructured mesh
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Giuffrida, C.a , Gruosso, G.b c , Repetto, M.a d e
Finite formulation of nonlinear magnetostatics with integral boundary conditions
(2006) IEEE Transactions on Magnetics, 42 (5), pp. 1503-1511. Cited 12 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-33646450112&partnerID=40&md5=7e9fe2b4a738a161ce3837f30e6d1041
AFFILIATIONS: Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, 10129 Torino, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, 20133 Milano, Italy;
Dipartimento di Elettronica ed Informazione, Politecnico di Milano, Milano, Italy;
Department of Fundamentals of Electrical Engineering, Italy;
Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, Torino, Italy
ABSTRACT: This paper describes two hybrid methods coupling finite formulation of electromagnetic fields (FFEF) in a bounded domain to integral boundary conditions taking into account far field conditions. The two hybrid techniques use different boundary conditions: the first formulation is based on Green’s function applied to magnetization source inside bounded domain while the other one is based on a boundary-element method on its external surface. Details about the coupling terms are given and handling of different magnetization sources is described, including the fictitious magnetization sources coming from nonlinear solutions. The proposed methods are validated versus different benchmark cases. Comparisons between the two techniques have been performed using different criteria (accuracy and convergence, memory requirements, etc.). © 2006 IEEE.
AUTHOR KEYWORDS: Boundary-element method; Finite formulation of electromagnetic fields; Green’s function; Hybrid formulations; Nonlinearity
DOCUMENT TYPE: Article
SOURCE: Scopus

Canova, A.a , Gruosso, G.b , Tartaglia, M.a
Insulated joint for corrosion protection of buried subway gallery structure: Consideration on cable ground connection
(2006) IEEE Transactions on Power Delivery, 21 (2), pp. 966-970. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-33645729833&partnerID=40&md5=3321429c41069a1a207d59c538d422e1
AFFILIATIONS: Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, Torino 10129, Italy;
Dipartimento di Elettronica ed Informatica, Politecnico di Milano, Milano 20133, Italy
ABSTRACT: Protection against corrosion of a subway’s metallic structure can be performed by insulated joints at the interface between galleries and stations. A preliminary analysis shows some differences in stray current flowing and a possible improvement of protection depending on the joint region configuration. This analysis is performed by means of a commercial three-dimensional finite-element method. A consequence of using insulated joints is a suitable grounding of the sheaths belonging to power and signal cables laying inside the gallery and particular care in connecting them to ground electrical masses or other metallic structures in order to avoid shunting insulated joints. Induced voltages and currents must be predicted to avoid any danger in both under-rated and fault conditions. © 2006 IEEE.
AUTHOR KEYWORDS: Corrosion; Railway; Stray current
DOCUMENT TYPE: Article
SOURCE: Scopus

Gruosso, G.a , Repetto, M.b
Implementation of a network model of hysteresis
(2006) Physica B: Condensed Matter, 372 (1-2), pp. 53-56.
http://www.scopus.com/inward/record.url?eid=2-s2.0-30844461229&partnerID=40&md5=4f88ca88fb454b532af10c729c018a9b
AFFILIATIONS: Dipartimento Elettronica e Informazione, Politecnico di Milano, P.za Leonardo da Vinci 32, I-20133 Milano, Italy;
Dipartimento Ingegneria Elettrica, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy
ABSTRACT: A network model of hysteresis based on elementary cells made up with piece-wise linear resistors and a linear capacitor has been presented in the literature and its theoretical properties have been investigated. This model allows to simulate hysteresis in a circuit solver without requiring any modification to its source code. Despite its appealing features, some cautions must be used for the treatment of the interface between the model and the rest of the circuit and for the handling of nonlinear resistors which can introduce some convergence problems in the network solution. These topics are investigated and some results on a simple test case are presented and discussed. © 2005 Elsevier B.V. All rights reserved.
AUTHOR KEYWORDS: Network model of hysteresis; Nonlinear circuit; Static hysteresis model
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Freschi, F.a , Gruosso, G.b , Repetto, M.a
Use of finite formulation of electromagnetic field for solving PEEC problems on unstructured grids
(2005) ICEAA 2005 – 9th International Conference on Electromagnetics in Advanced Applications and EESC 2005 – 11th European Electromagnetic Structures Conference, pp. 455-458. Cited 1 time.
http://www.scopus.com/inward/record.url?eid=2-s2.0-34547290603&partnerID=40&md5=4f654ee5dc4114061dbc624d123411db
AFFILIATIONS: Dipartimento di Ingegneria Elettrica, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
ABSTRACT: Finite Formulation of Electromagnetic Fields allows to define an algebraic form of Maxwell’s equations on an unstructured discretization system. This characteristic is here exploited by defining an equivalent circuit for an unstructured mesh of surface electrodes in an homogeneous dielectric region The constitutive equation of this partial components can be written by means of the electric field integral equation. In this way a generalization of the well known PEEC technique to the case of triangular discretization is obtained. Some results are presented on benchmark cases showing a good agreement with the ones available in the literature.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Canova, A.a , Freschi, F.a , Gruosso, G.b , Vusini, B.a
Genetic optimisation of radial eddy current couplings
(2005) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 24 (3), pp. 767-783. Cited 2 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-22644447613&partnerID=40&md5=a423733f89c0cc60a1675d009ed39af7
AFFILIATIONS: Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, Turin, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milan, Italy
ABSTRACT: Purpose – The purpose of this paper is to obtain a fully analytical model of an eddy current coupler and to use it in a multi-objective optimisation algorithm. Design/methodology/approach – Analytical expressions of device performances are adopted in the objective function and are obtained from a closed solution of the field problem. The optimisation has been carried out by considering both the torque and the momentum of inertia of the object. Two different structures have been considered. Findings – A fully analytical expression of the torque has been obtained for two different geometrical configurations. The optimisation procedure has been used to compare these structures and it is possible to observe that the DSPM performances are better than the SSPM ones. Research limitations/implications – To obtain a closed form of the torque function, the non-linearities of the iron have been neglected. Nevertheless, in the optimisation procedure has been limited the magnetic flux density in the iron core to a feasible value in the linear part of the ferromagnetic characteristic. The thermal effects have been neglected. Pratical implications – In the industry, eddy current couplers can be used as transmission, dampers and brakes. The use of objective functions (OFs) in a closed formulation allows to perform a light optimisation from the point of view of the time computation and to drastically increase the development efficiency. Originality/value – In this paper, a model for computing the electromagnetic behaviour of eddy current couplers is presented. The optimisation of both the torque and the inertia momentum allows to obtain good static and dynamic performances. © Emerald Group Publishing Limited.
AUTHOR KEYWORDS: Eddy currents; Optimization techniques
DOCUMENT TYPE: Article
SOURCE: Scopus

Canova, A.a , Gruosso, G.b , Repetto, M.a
An integral approach based on dual discretization and method of moment for the solution of static electric field
(2005) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 24 (2), pp. 446-457.
http://www.scopus.com/inward/record.url?eid=2-s2.0-20444458291&partnerID=40&md5=943bfbe8c3865921af5e45639f2d09a2
AFFILIATIONS: Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, Torino, Italy;
Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milano, Italy
ABSTRACT: Purpose – The scope of the work is to provide an hybrid numerical technique for the solution of electric field. Design/methodology/approach – In this paper an integral approach for the solution of static electric field based on a dual discretization (DD) and on a surface method of moment (MoM) is presented. The proposed technique is applied to the solution of 3D electric field problems where different perfectly conducting bodies are placed in a homogeneous and isotropic medium. The approach is also extended to the analysis of static current field. In the presented formulation MoM is applied on a surface domain which is discretized according to a baricentrical dual scheme. Findings – The procedure has been applied to several practical cases and it represents an efficient tool for the evaluation of lumped circuit parameters as capacitances of 3D conducting bodies and ground resistance of grounding systems. Research limitations/implications – The formulation presented in the paper is limited to the calculus of electric field in homogeneous media. For future development the authors are working in order to include non-homogeneous media. Practical implications – The proposed approach aids the designer of electrical systems as large scale grounding systems or integrated circuit connections in the calculations of lumped electrical parameters. Originality/value – The originality of the paper lies in the coupling of MoM with finite formulation and DD. © Emerald Group Publishing Limted.
AUTHOR KEYWORDS: Electric fields; Integral equations; Meshes; Method of moments
DOCUMENT TYPE: Article
SOURCE: Scopus

Gruosso, G.a , Repetto, M.b
Identification and simulation of a circuit-based model of magnetic hysteresis
(2005) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 24 (2), pp. 534-545.
http://www.scopus.com/inward/record.url?eid=2-s2.0-20444482398&partnerID=40&md5=c68e98b1c8f1456d0472e192848f4dbb
AFFILIATIONS: Dipartimento di Elettronica e Informazione, Politecnico di Milano, Milano, Italy;
Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, Torino, Italy
ABSTRACT: Purpose – The scope of the work is to provide an identification procedure for an hysteresis model based on nonlinear circuit cells. Design/methodology/approach – An identification procedure for an hysteresis model based on nonlinear circuit cells is presented. The response of elementary cell is equal to a generalized play operator. The procedure allows the identification of the limit symmetric hysteresis loop and of minor loops. The identification procedure is based on the relationship between the circuit parameters and the discretization of the first derivative of the BH curve by means of a staircase function. Findings – The model obtained is employed for the simulation of soft magnetic composite material cores under different supply voltage waveforms. The proposed identification procedure is able to define an accurate model of an hysteretic material with a low number of elemental network cells. The identification algorithm is simple and makes use of the limit hysteresis cycle only. Symmetric minor loops are used to tune “soft” operators for the correct reconstruction of cycles which do not reach saturation. Research limitations/implications – The model is limited to scalar and static hysteresis model. Practical implications – The model obtained can be used in network simulator like SPICE in order to model circuits in which magnetic devices are involved. Originality/value – The circuit hysteresis model has been presented in literature, while its identification is newly proposed by the authors. © Emerald Group Publishing Limited.
AUTHOR KEYWORDS: Magnetic measurement; Modelling
DOCUMENT TYPE: Article
SOURCE: Scopus

Gruosso, G.a , Repetto, M.b
Identification method for a circuit model of scalar static hysteresis
(2004) IEEE Transactions on Magnetics, 40 (6), pp. 3467-3473. Cited 4 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-9644302994&partnerID=40&md5=a36c5c965b8624b6f7d7813cfb9bdaa4
AFFILIATIONS: Dipartimento di Elettronica, Politecnico di Milano, 32-I-20133 Milano, Italy;
Dipto. Ingegneria Elettrica I., Politecnico di Torino, 24-10-129 Torino, Italy
ABSTRACT: We present a new identification procedure for a hysteresis model based on nonlinear circuit cells. The response of elementary cells is equal to a generalized play operator. The procedure identifies exactly the limit symmetric hysteresis loop and can minimize the reconstruction error on minor loops. We present test cases for three different soft magnetic materials with peculiar behavior and we discuss the results.
AUTHOR KEYWORDS: Circuit model of hysteresis; Hysteresis; Identification; Soft magnetic material
DOCUMENT TYPE: Article
SOURCE: Scopus

Schofield, N.a d , Canova, A.b , Gruosso, G.b , Repetto, M.b , Ottella, M.c
The application of soft magnetic composites to the design of tubular linear actuators
(2004) International Journal of Applied Electromagnetics and Mechanics, 19 (1-4), pp. 225-229. Cited 5 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-2442562437&partnerID=40&md5=715fa243f05a1f7a85632c0abd08a9db
AFFILIATIONS: Dept. of Electronic Engineering, University of Sheffield, Sheffield, United Kingdom;
Dipto. Ingegneria Elettrica Indust., Politecnico di Torino, Torino, Italy;
Centro Ricerche Fiat, Orbassano, Torino, Italy;
Department of Electronic Engineering, University of Sheffield, Sheffield, S1 3JD, United Kingdom
ABSTRACT: The paper presents the design synthesis and construction of a tubular linear, permanent magnet actuator for automotive applications. The application of soft magnetic composites in permanent magnet machines is discussed, since conventional lamination techniques are cost prohibitive for the tubular linear topology considered. The linking of analytic and finite element techniques in the design synthesis is presented along with characterisation test data from a prototype actuator constructed to validate the design procedure.
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Canova, A.a , Gruosso, G.b , Repetto, M.a
Optimal shielding of low frequency fields
(2004) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 23 (1), pp. 173-186. Cited 5 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-1442313329&partnerID=40&md5=b1b49ce9c2f270427230fc1b10882297
AFFILIATIONS: Dipto. di Ing. Elettrica Industriale, Politecnico di Torino, Turin, Italy;
Dipartimento di Elettronica, Politecnico di Milano, Milan, Italy
ABSTRACT: Shielding of electromagnetic low frequency field can be performed by means of conductive sheets. These sheets have a thickness which is usually two or three orders of magnitude lower than their other dimensions, thus their effects must be modeled by means of special numerical techniques. In this paper, two integral formulations for the analysis of conductive shields are presented: one is two-dimensional and is based on a multiconductor system, while the other, three-dimensional, is based on a finite formulation of electromagnetic fields. Once these analysis tools have been introduced, this paper presents the study of different shielding systems and a problem of optimal exploitation of conductive material.
AUTHOR KEYWORDS: Electromagnetism; Optimization techniques
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Bottauscio, O.a , Manzin, A.a , Canova, A.b , Chiampi, M.b , Gruosso, G.c , Repetto, M.b
Field and circuit approaches for diffusion phenomena in magnetic cores
(2004) IEEE Transactions on Magnetics, 40 (2 II), pp. 1322-1325. Cited 13 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-2342521428&partnerID=40&md5=a7986b20b2e413c08eac26891a0d030d
AFFILIATIONS: Ist. Elettrotecn. Naz. Galileo F., I-10135 Torino, Italy;
Dipto. Ingegneria Elet. Industriale, Politecnico di Torino, I-10129 Torino, Italy;
Dipartimento di Elettronica, Politecnico di Milano, 20133 Milano, Italy
ABSTRACT: This paper presents two approaches for nonlinear dynamic modeling of voltage-driven magnetic circuits. The field approach is based on a finite-element method; in two-dimensional laminated cores, an in-plane magnetic analysis is coupled with a one-dimensional eddy current solution across lamination thickness. The lumped parameter approach subdivides the magnetic core in flux tubes according to geometrical symmetries and solves the coupled electric and magnetic circuits. The two methods are applied to the analysis of magnetic cores and comparisons between them, and experimental data are performed and discussed.
AUTHOR KEYWORDS: Eddy currents; Finite-element method (FEM) analysis; Magnetic circuits
DOCUMENT TYPE: Conference Paper
SOURCE: Scopus

Canova, A.a , Gruosso, G.b , Repetto, M.a
Magnetic Design Optimization and Objective Function Approximation
(2003) IEEE Transactions on Magnetics, 39 (5 I), pp. 2154-2162. Cited 20 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-0141918459&partnerID=40&md5=1dc904b33bb9287e965a9030ea57f4f8
AFFILIATIONS: Dipto. Ingegneria Elettrica I., Politecnico di Torino, 10129 Torino, Italy;
Dipartimento di Elettronica, Politecnico di Milano, 20133 Milano, Italy
ABSTRACT: This paper addresses the problem of optimizing a device by using an interpolation of the objective function. Optimization by means of stochastic methods can explore the objective function and give reliable indications on its global extrema, but the number of function calls can be unacceptably large when numerically evaluated functions are used. An optimization procedure applied not directly on the objective function but on its interpolation can significantly reduce the cost of the optimization. An efficient coupling between interpolation technique and optimization method is needed both to explore features of the optimization algorithm and to exploit advantages of the interpolation. This paper analyzes the performance of a multiquadric interpolation procedure on analytical functions and on finite-element evaluations.
AUTHOR KEYWORDS: Genetic algorithm; Interpolation of objective function; Optimization; Response surface methodology
DOCUMENT TYPE: Article
SOURCE: Scopus

Canova, A.a , Gruosso, G.b , Repetto, M.a
Integral methods for analysis and design of low-frequency conductive shields
(2003) IEEE Transactions on Magnetics, 39 (4 II), pp. 2009-2017. Cited 24 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-0042766773&partnerID=40&md5=66966b4abc27682c35e98841eda81bb9
AFFILIATIONS: Dipto. di Ing. Elettrica Industriale, Politecnico di Torino, I-10129 Torino, Italy;
Dipartimento di Elettronica, Politecnico di Milano, I-20133 Milan, Italy
ABSTRACT: This paper presents and compares two different approaches to the analysis and design of nonferrous shields for extremely low-frequency magnetic fields. The first method is based on a circuital approach where the shield is modeled by a set of conductors coupled with each other by a matrix of self and mutual inductances. The second technique is based on an algebraic formulation of electromagnetic fields and adapted by means of integral equations to the analysis of thin conductive sheets. The paper shows the accuracy of the two methods for calculating induced current density inside the shield and for evaluating magnetic flux density in the shielded region.
AUTHOR KEYWORDS: Conductive shielding; Extremely low frequency; Finite formulation of electromagnetic fields; Thin conductor
DOCUMENT TYPE: Article
SOURCE: Scopus

Canova, A., Gruosso, G., Repetto, M.
Synthesis of linear actuators
(2001) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 20 (3), pp. 713-723. Cited 5 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-0035788004&partnerID=40&md5=ff9b7ac405ae4d5525743df63fff6006
AFFILIATIONS: Dipartimento di Ingegneria Elettrica Industriale, Politecnico di Torino, Torino, Italy
ABSTRACT: The synthesis of electro-mecliank actuators is formulated as a constrained optimization problem tvliere some performance fumtion ofthe device is to be met, subject to the satisfaction of some constraints about its dimensions and supply conditions. The optimization problem is tackled by means of a genetic algorithm coupled to a multi-objective definition of the objective function tliat merge together objectives and constraints in one single scalar objective function. A fast magnetic analysis tool lias been developed so tliat the computational cost ofthe genetic optimization run is acceptable. Some results about the synthesis of a tubular linear motor in tivo sizes are presented and discussed. © MCB University Press,.
AUTHOR KEYWORDS: Actuators; Genetic algorithms; Optimization
DOCUMENT TYPE: Article
SOURCE: Scopus

Bianchi, N.a , Canova, A.b , Gruosso, G.a , Repetto, M.b , Tonel, F.a
Analytical and finite element design optimisation of a tubular linear IPM motor
(2001) COMPEL – The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, 20 (3), pp. 777-795. Cited 10 times.
http://www.scopus.com/inward/record.url?eid=2-s2.0-0035787626&partnerID=40&md5=75fb2ed3de234311f65e72b2afb3b9a4
AFFILIATIONS: Department of Electrical Engineering, University of Padova, Padova, Italy;
Department of Electrical and Industrial Engineering, Politechnic of Torino, Torino, Italy
ABSTRACT: The optimisation of a tubular linear motor with interior permanent magnets is described. For a rapid design the whole process is divided in three parts: an analytical approach for the a preliminary investigation, a parametric analysis by means of a finite element method and an optimisation. The obtained results show that the adopted optimisation process is efficient for rapid and effective optimisation of the tubular linear motor. © MCB University Press,.
AUTHOR KEYWORDS: Design; Finite ekment; Linear motors; Optimisation
DOCUMENT TYPE: Article
SOURCE: Scopus