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Power Conversion Circuit Analysis by Extending the Vision of Impedance
Date: 2014/3/4             Browse: 1139

Speaker: Dr. Junrui Liang (Assistant Professor, SIST, ShanghaiTech University)

Time:      March 4, 2014 (Tuesday), 3:15 to 4:15pm

Location: Room 220, Building 8#


The concept of impedance has once brought a lot of convenience to the ac circuit analysis. Yet, strictly speaking, conventional impedance approach can only be applied to linear time-invariant (LTI) systems; such limitation confined its application in most modern power technologies, where nonlinear components, such as diodes and transistors, are extensively involved. Through extending the vision of this long-standing impedance concept, we explored the revival of impedance approach in two kinds of power conversion systems, including pure electrical Class-E power amplifier (Class-E PA) and electromechanically coupled piezoelectric energy harvesting (PEH) system. The vision extension led to the development of very efficient algorithms for the analysis and optimization of these systems. For instance, Class-E PA optimization based on this technology runs more than 100 times faster than the state of the art. More importantly, integrated analysis of PEH system, in terms of impedance, was achieved for the first time. The holistic insight associated with the proposed integrated analysis helps clarify a series of crucial but previously overlooked or even misunderstood issues in this area. To end this talk, the speaker summarizes his personal insights on interdisciplinary research based on his previous research experiences, in response to the emphasis of interdisciplinary collaboration in ShanghaiTech.


Dr. Junrui Liang has received the Ph.D. degree in Mechanical and Automation Engineering from The Chinese University of Hong Kong (CUHK), Hong Kong, in 2010. Since November 2013, he is with the School of Information Science and Technology, ShanghaiTech University, China, as an Assistant Professor. His most significant contribution in research was that he extended the impedance modeling and analysis, which conventionally was only used for linear systems, to some nonlinear power conversion systems such as the class-E power amplifier and piezoelectric energy harvesting systems. His recent research interests include: dynamics of nonlinear electromechanical coupling systems, kinetic energy harvesting and vibration control, electrical power conversion and utilization research, renewable energy, etc. Since 2008, He has published 17 peer-reviewed technical papers in international journals and conferences and received four research awards. Dr. Liang is a member of IEEE and ASME, a reviewer of several international journals and conferences, and section chair of 2014 SPIE SS/NDE international conference.  

SIST-Seminar Series-14002