SEECS Colloquium

In the last two decades, the power inverter technology has seen tremendous advancement with a variety of circuit topologies for a wide range of applications. Notably the resonant circuit based soft-switching inverters and multilevel inverters have been the major research subjects. In general, a power electronics technology takes 15 years to be fully developed and matured for commercial applications. Recently, a few examples of multilevel inverters using late 1970s patented circuits have been successfully commercialized. With the more and more demand in efficiency power conversion for applications such as electric vehicles and distributed energies, it is anticipated that more and more advanced inverter technologies will be seen in the commercial place. The presentation will start with an overview of soft-switching and multilevel inverters. The pros and cons of these circuit topologies will then be compared. Finally, applications of these inverters in electric vehicles and utility distributed energies will be discussed.

Jih-Sheng (Jason) Lai received M. S. and Ph.D. degrees in electrical engineering from the University of Tennessee, Knoxville, in 1985 and 1989 respectively.

From 1980 to 1983, he was the Head of the Electrical Engineering Department of the Ming-Chi Institute of Technology, Taipei, Taiwan, where he initiated a power electronics program and received a grant from his college and a fellowship from the National Science Council to study abroad. In 1986, he became a staff member at the University of Tennessee, where he taught control systems and energy conversion courses. In 1989, he joined the Electric Power Research Institute (EPRI) Power Electronics Applications Center (PEAC), where he managed EPRI-sponsored power electronics research projects. From 1993, he worked with the Oak Ridge National Laboratory as the Power Electronics Lead Scientist, where he initiated a high power electronics program and developed several novel high power converters including multilevel converters and auxiliary resonant snubber based soft-switching inverters. His work brought him several distinctive awards including a Technical Achievement Award in Lockheed Martin Award Night, two IEEE IAS Conference Paper Awards from Industrial Power Converter Committee, one IEEE IECON Best Paper Award, and an Advanced Technology Award from Inventors Clubs of America. Since August 1996, he has been with the Virginia Polytechnic Institute and State University as an Associate Professor. His main research areas are in high power electronics converter topologies, motor drives, and utility power electronics interface and application issues. He has published more than 105 technical papers and 2 books. He received 8 U.S. patents in the area of high power electronics and their applications.

Dr. Lai is a senior member of IEEE and the Chairman of the IEEE Power Electronics Society Standards Committee. He is chairing a Technical Committee for the 2001 DOE Future Energy Challenge. He is also a member of Phi Kappa Phi and Eta Kappa Nu honor societies