A drain current based short circuit protection technique for SiC MOSFET

Abstract

SiC MOSFETs based power converters are an attractive alternative to IGBTs due to the reduced size and weight of the converter. However, as the leakage inductance is very small it causes a rapid rise in device current under short circuit conditions. As a result, SiC MOSFET cannot withstand short circuit faults for durations as long as the IGBT, thus, the reliability of SiC MOSFET can be a hindrance to it's widespread adoption. This paper analyzes the shortcomings of the present short circuit protection techniques which are presented in literature. Further, a practical short circuit protection technique for SiC MOSFETs by sensing the drain current id from the device di/dt has been presented in the paper. The proposed method eliminates the delays in the present short circuit protection methods and can detect Hard Switching Fault (HSF) and Fault Under Load (FUL) as well.