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The Re-Emergence of Current-Source Inverters in Future Machine Drives

ECE Colloquia Virtual Seminar

Wednesday, September 23, 2020

Location: Current Students & Faculty will Receive Zoom Access via Canvas

Thomas M. Jahns
Grainger Professor of Power Electronics and Electric Machines at The University of Wisconsin – Madison

Current-source inverters (CSIs) once dominated the world of adjustable-speed motor drives until MOS-gated switches forced a transition to voltage-source inverters (VSIs) more than 30 years ago. But will this continue to be true during coming years as wide-bandgap power semiconductor switches rise to ascendancy? The objective of this presentation is to make the case for a revival of interest in pulsewidth-modulated (PWM) CSIs for future machine drives, with particular attention devoted to the advantages they offer for high-performance machine drives.  WBG switches in combination with PWM-CSIs offer a potent combination of advantages that include sinusoidal output excitation waveforms, high efficiency, reduced EMI, suppression of motor terminal overvoltages and bearing damage, and compatibility with high-temperature operation. In addition, the absence of free-wheeling diodes in CSIs provides the basis for significantly reduced risks associated with terminal short-circuit faults in PM machines compared to VSI excitation. The presentation will close with a discussion of the special appeal of PWM-CSIs in future integrated motor drives (IMDs) and the remaining technical challenges that must be overcome for CSIs to rise again from the ashes.


Thomas M. Jahns received his bachelors, masters, and doctoral degrees in electrical engineering from MIT, Cambridge, MA (USA). 

Dr. Jahns joined the faculty of the University of Wisconsin – Madison (USA) in 1998 as the Grainger Professor of Power Electronics and Electric Machines in the Department of Electrical and Computer Engineering.  He is a Co-Director of the Wisconsin Electric Machines and Power Electronics Consortium (WEMPEC), a university/industry consortium with over 80 international sponsors.  

Prior to coming to UW-Madison, Dr. Jahns worked at GE Corporate Research and Development in Niskayuna, NY (USA) for 15 years, where he pursued new power electronics and motor drive technology in a variety of research and management positions. His current research interests at UW-Madison include high-performance electrified propulsion, integrated motor drives, and high-penetration of distributed energy resources. 

Dr. Jahns is a Fellow of IEEE.  He received the 2005 IEEE Nikola Tesla Technical Field Award “for pioneering contributions to the design and application of AC permanent magnet machines”.  Dr. Jahns is a Past President of the IEEE Power Electronics Society and the recipient of the 2011 Outstanding Achievement Award presented by the IEEE Industry Applications Society.  He was elected to the US National Academy of Engineering in 2015.

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