Investigations on acceptable breakdown voltage variation of parallel-connected SiC MOSFETs applied to olid-state circuit breakers

Abstract

This paper aims to investigate the acceptable breakdown voltage variation of parallel-connected SiC power MOSFETs applied to solid-state circuit breakers (SSCB) under different total current conditions and its numerical simulation model. Due to variation of breakdown voltage among SiC power MOSFETs, the current flowing through devices is imbalanced during emergency interruption of SSCBs, which can drive some of the devices into thermal destruction. The unclamped inductive switching (UIS) test was imaged as the emergency interruption of SSCBs in this research. The UIS test of two parallel-connected SiC power MOSFETs was implemented. Proposed numerical simulation represents the experimental results with failure criteria by considering self-heating due to imbalanced current flowing. And it was found that the acceptable breakdown voltage variation and the total current have a linear relation.