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New Junction Temperature Balancing Method for a Three Level Active NPC Converter

2012; Taylor & Francis; Volume: 22; Issue: 2 Linguagem: Inglês

10.1080/09398368.2012.11463818

0939-8368

Erika Hauk, Rodrigo Álvarez, Jens Weber, Steffen Bernet, Daniel Andler, José Rodríguez,

Induction Heating and Inverter Technology

SummaryThe three-level Neutral Point Clamped Voltage Source Converter (3L-NPC VSC, 3L-ANPC VSC) has many attractive features like its high reliability and availability. Nowadays, this technology is mature and can be found in several industrial applications [1], [2]. Some common applications are pumps, fans, compressors, mixers, extruders, crushers, rolling mills, mine hoist drives and excavators.The three-level Active NPC VSC (3L-ANPC VSC) was introduced in 2001 to overcome the drawbacks of the conventional 3L-NPC VSC [3]. The 3L-ANPC VSC includes additionally active switches parallel to the NPC diodes for clamping the neutral tap of the converter. It features 3 extra switch states in contrast to the conventional 3L-NPC VSC, which enable the possibility to reduce the temperature imbalance and/or to increase the output frequency or the converter power. In order to use the potential of the 3L-ANPC VSC and to balance the losses among the semiconductors, the implementation of a temperature balancing strategy is necessary [4] and [5].The medium voltage 3L-ANPC VSC is especially advantageous in the following applications:– High power applications, where the required output power cannot be archived without a serial/parallel connection of devices.– Medium voltage converters, where the switching frequency should be increased without decreasing the converter power (e.g. applications which require a sine filter or high speed applications).– Applications where the nominal converter current is required at low modulation index and low fundamental frequencies (e.g. zero speed operating points, hot and cold rolling mill applications, converters for doubly fed induction generators, etc.).The starting point for the derivation of the new balancing algorithm was the Active Loss Balancing (ALB) system, which is reported in [4] and [5]. The new temperature balancing scheme profits from the features of Predictive Control [6] in order to precalculate the conduction and the switching losses and finally the temperature of each semiconductor up to the future commutation to the zero state, i.e. over the next period of the switching frequency. The precalculated maximal junction temperature will be used for the control strategy in order to determine the optimal switch state to be applied.Some additional features of the new balancing algorithm with respect to the ALB algorithm are: consideration of the conduction losses fed into the balancing algorithm, regard of the temperature ripple between two consecutive commutations and the use of a control criteria (cost function) in the selection of the zero state [6]. The algorithm is implemented in Matlab and compared with the 3L-NPC VSC using experimental data of a 4.5 kV Press-pack IGBT and Diode for the calculation of the losses. The comparison shows a potential to increase the output power of the 3L-ANPC VSC.Keywords: Medium VoltagePower ConverterMulti Level Converters3L-ANPCPress-pack IGBTPower Semiconductor DeviceThermal design Additional informationNotes on contributorsErika HaukErika Hauk was born in Braila, Romania in 1983. She has received the Engineer degree from the Transilvania University Brasov in 2007. She was an Erasmus/Socrates scholarship holder during 2007 for the diploma thesis at the Ruhr Universität Bochum, Germany. She is currently with the Department of Electrical Engineering and Information Technology, University of Technology, Dresden, Germany under a grant of the DAAD (German Academic Exchange Service). Her major research interests are medium-voltage converter topologies, thermal model ing of power converters and PWM schemes.Rodrigo ÁlvarezRodrigo Alvarez was bom in Santiago, Chile. He received the Electronic Eng. and M. Sc. Degree in Power Electronics from the Universidad Técnica Federico Santa Maria (UTFSM), Valparaiso Chile, in 2006. In 2007 he joined the Professur für Leistungselektronik at the Dresden Technical University, he is currently working toward the Ph.D. degree in Power Electronics. His research interests include characterization and application of modern medium voltage semiconductors in medium voltage drives, modem control techniques for medium voltage semiconductors and adjustable speed drives.Steffen BernetSteffen Bernet (M’97) received the diploma degree from Dresden University of Technology in 1990 and the Ph.D. degree from Ilmenau University of Technology in 1995, both in electrical engineering. During 1995 and 1996, he worked as Postdoc in the ECE Department of the University of Wisconsin – Madison. In 1996, he joined ABB Corporate Research, Heidelberg (Germany) where he led the Electrical Drive Systems Group. From 1999 to 2000 he was subprogram manager responsible for the ABB research in the areas Power Electronics Systems, Drives and Electric Machines. From 2001 to 2007 he was Professor for Power Electronics at Berlin University of Technology. Since June 2007 he has been Professor at Dresden University of Technology. During the past seventeen years, Dr. Bernet has conducted comprehensive research on power semiconductors, static power converters and ac motor drives. Dr. Bernet has published more than 90 papers in the field of power electronics. He is a recipient of the 2005 Second Prize Paper Award of the IEEE-PESC and IEEE IAS committee second prize paper awards from the industrial power converter committee and the power electronic devices and components committee.Daniel AndlerDaniel Andler (M’08) was born in Puerto Varas, Chile, in 1983. He received the diploma and the MSc. degree from the Universidad Técnica Federico Santa María (UTFSM) in 2009, both in electrical engineering. In 2010 he joined the Professur für Leistungselektronik at the Technische Universität Dresden (TUD). He is currently working toward the joint Ph.D. degree at the UTFSM and the TUD in Power Electronics. His research interests include power electronics, static converters and drives, power semiconductors, energy efficiency and control of power converters.Jose RodríguezJosé Rodriguez (M’81-SM’94-F10) received the Engineer degree in electrical engineering from the Universidad Federico Santa Maria (UTFSM), Valparaiso, Chile, in 1977 and the Dr.-Ing. degree in electrical engineering from the University of Erlangen, Erlangen, Germany, in 1985. He has been with the Department of Electronics Engineering, University Federico Santa Maria since 1977, where he is currently full Professor and Rector. He has co authored more than 300 journal and conference papers. His main research interests include multilevel inverters, new converter topologies, control of power converters, and adjustable-speed drives. Prof. Rodriguez is Associate Editor of the IEEE TRANSACTIONS ON POWER ELECTRONICS and IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS since 2002. He received the Best Paper Award from the IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS in 2007, the Best Paper Award from the IEEE INDUSTRIAL ELECTRONICS MAGAZINE in 2008 and Best Paper Award from the IEEE TRANSACTIONS ON POWER ELECTRONICS in 2010. Dr. Rodriguez is member of the Chilean Academy of Engineering and Fellow of the IEEE.