Using SiC MOSFETs to improve reliability of EV inverters

Abstract

Wide bandgap semiconductor devices like SiC have achieved more and more attentions in electric vehicles-(EVs) because of their high-temperature capability, high-power density, and high efficiency. As all known, EVs frequently operate in acceleration, deceleration and low speed driving in urban traffic. Thus, not only the rated operation condition should be considered, but also some extreme operation conditions. In order to study the variations of junction temperature of SiC-based MOSFETs comparing with Si-based IGBT of EVs inverter at different operation condition, an electro-thermal coupling model for 3-phase inverter of permanent magnet synchronous motor (PMSM) is used in this paper. Simulation results show that the maximum junction temperatures and junction temperature fluctuations of SiC MOSFETs are quite lower than that of Si IGBTs in all test conditions.