AAU logo

Events at Department of Energy Technology

Guest lectures by Dr. Z. John Shen and Prof. Dr. Ulrike Grossner


15.08.2019 kl. 10.00 - 12.00


There will be two guest lectures on August 15 prior to the PhD defence of Lorenzo Ceccarelli


Wide Bandgap Power Electronics: Major Challenges and Potential Pathways for Commercialization


Dr. Z. John ShenGrainger Endowed Chair Professor, Illinois Institute of Technology, Chicago


10:00 -11:00


WBG power electronics research has kicked into high gears in the past few years. Numerous power converter designs, in which the existing silicon power devices were simply replaced with new WBG devices, have been reported and demonstrated tangible performance benefits. However, considering the high cost and other constraints of today’s WBG devices, the power electronics industry may need to look into other innovative pathways for large scale commercialization beyond the simple “brute force” substitution approach. In this talk, we will first examine the unique advantages and major challenges of WBG vs. silicon devices, and propose a few potential pathways to overcome the barriers. WBG devices should be judiciously deployed in future power electronic systems to maximize their performance benefits while low cost silicon devices should be used wherever their performance suffices. Combined or mixed use of both WBG and silicon devices should be explored at the component, converter, and system levels. This hybrid approach essentially allows WBG and silicon devices to do what they do best, individually and collectively. Several examples and case studies will be discussed along this line of thinking. In particular, we will discuss a paradigm of partial power processing (P3) which combines low-frequency high-efficiency Si base power processing with high-frequency, fractional power WBG micro-STATCOM. This approach may help deliver better performing and more cost-effective power electronic designs, and expand the WBG market at the same time. To address the current reliability concerns with WBG devices, we will look into fault-tolerant operation and control strategies of multilevel and multithread converter topologies. Furthermore, we will discuss the potential of expanding power ratings through multilevel topologies and a differential power processing approach. The purpose of this talk is to stimulate discussions and debates among the research community on these nonconventional technical approaches in commercializing WBG power electronics.

About the lecturer

Z. John Shen received BS from Tsinghua University, China, in 1987, and M.S. and Ph.D. degrees from Rensselaer Polytechnic Institute, Troy, NY, in 1991 and 1994, respectively. He is currently Grainger Endowed Chair Professor in Electrical and Power Engineering at Illinois Institute of Technology. Between 1994 and 1999, he held a variety of positions with Motorola Inc. He was on faculty of the University of Michigan-Dearborn between 1999 and 2004, and the University of Central Florida between 2004 and 2012. During 2002-2012 he was also a co-founder and board member of Great Wall Semiconductor (now a division of Renesas), responsible for developing MHz-frequency lateral power MOSFET technologies. His research interests include power electronics, power semiconductor devices and ICs, automotive electronics, and renewable and alternative energy systems. He has published over 250 journal and conference articles, and holds 18 issued and several pending U.S. patents in these areas. Dr. Shen is a recipient of the 2012 IEEE Region 3 Outstanding Engineer Award, the 2003 NSF CAREER Award, the 2006 IEEE Transaction Paper Award from IEEE Society of Power Electronics, the 2003 IEEE Best Automotive Electronics Paper Award from IEEE Society of Vehicular Technology, and the 1996 Motorola Science and Technology Award. He has been an active volunteer in the IEEE Power Electronics Society (PELS), and has served as VP of Products 2009-2012, Associate Editor and Guest Editor in Chief of the IEEE Transactions on Power Electronics, General Chair of several major IEEE conferences including ECCE2016 and ISPSD2018. He is also a Fellow of the U.S. National Academy of Inventors.



SiC - a power semiconductor material almost like Si


Prof. Dr. Ulrike Grossner, Advanced Power Semiconductor Laboratory, ETH Zurich, Switzerland


11:00 -12:00


Silicon carbide is the most advanced wide bandgap semiconductor material with numerous applications in power electronics already. The material itself has been investigated for this purpose since the late 1980s, and its processing is rather similar to conventional silicon technology. This makes SiC technology comparably mature. However, there are still obstacles to faster and further commercialization: a perceived reliability concern, variations within one series of commercial devices and slightly different control and performance parameters than used for Si technology.

The talk aims at focusing on the specific technology and simulation steps useful for understanding SiC technology today as well as the necessary changes to what is known from silicon. Examples are based on research projects at the Advanced Power Semiconductor Laboratory, ETH Zurich, Switzerland.

About the lecturer

Ulrike Grossner received the Dipl.-Phys. and Dr. rer. nat. degrees from Friedrich-Schiller-University Jena, Jena, Germany, in 1997 and 2000, respectively. In 2014, she became a Full Professor with ETH Zurich, Zurich, Switzerland, where she established the Advanced Power Semiconductor Laboratory, working on devices and packaging for advanced power semiconductors.

THE guest lectures WILL TAKE PLACE in Pon 111 in the auditorium and all are welcome.



Department of Energy Technology


Pontoppidanstræde 111, auditorium 1.177