ICCCAS Invited Speaker

Toru Sai

Tokyo Polytechnic University, Japan

Biography: Toru Sai (Member, IEEE) received the B.S., M.E., and the Dr. Eng. degree in electrical engineering from Chuo University, Tokyo, Japan, in 1986, 1988, and 2012, respectively. In 1988, he joined the research and development center of Yokogawa Electric Company, Tokyo, Japan. From 2016 to 2020, he was a Project Research Associate with The University of Tokyo, Tokyo, Japan. Currently, he is a Professor at Tokyo Polytechnic University and a Research Fellow at the Institute of Industrial Science, the University of Tokyo. His current research interests include DC-DC converters, Gate drivers, and A/D converters. He received the Best Paper Award in 2019 IEEE International Future Energy Electronics Conference.
Speech Title: Multi-Stacked Series Capacitor Boost Converter for DC Microgrids
Abstract: This presentation introduces a novel high step-up DC-DC converter designed for DC microgrids. The proposed converter boosts a low input voltage of 20 V up to 400 V, achieving a high conversion ratio (CR) of 20. Its topology integrates a basic boost converter (BBC) with series capacitor boost converters (SCBCs), which are formed by simply adding a series capacitor to the BBC. By stacking three SCBC stages on top of the BBC and driving them with multi-phase clock signals, the converter achieves a high theoretical conversion ratio of 4/(1−D).
All switches are low-side driven, and the design maintains a common ground between the input and output. The converter ensures uniform voltage stress of VO/4 on the switching transistors and a reverse voltage of VO/2 on the diodes. In addition, the inductors carry the same average current of IO/(1−D). These features simplify component selection and reduce the variety of components required.
The operating principles have been verified using LTspice simulations. Experimental results from a laboratory prototype demonstrate an efficiency of 95% at an output power of 160 W.