Parallel Configuration of SiC and Si FETs in LLC Resonant Converter for Battery Charger of Railway Transportation

Abstract

Wide-Band-Gap (WBG) switching semiconductor has been improved for higher efficiency and higher power density. Especially, SiC FET is the most attractive switching semiconductor for mid-voltage and high power applications, such as, railway transportation. Its desired features for high power converter are low on-state resistance, thermal stability, no reverse recovery, high switching speed, and so on. However, faster switching speed derives higher dv/dt of drain-source voltage, then this result in larger voltage ringing and worse switching noise. In this paper, parallel configuration of SiC FET and Si FET is proposed to suppress voltage ringing and minimize switching noise. Based on the characteristics of output capacitances of both SiC and Si FETs, the switching performances of single SiC FET and parallel connection of SiC/Si FETs are compared of voltage ringing and switching noise in LLC resonant converter for 10kW battery charging module of railway transportation. ? The Korean Institute of Electrical Engineers