Analysis of Short-Circuit Characteristics and the Design of a Novel Protection Circuit for SiC MOSFETs

The short-circuit capability is one of the important issues that are related to the safe operation of silicon carbide (SiC) MOSFETs. The short-circuit mechanism of SiC MOSFET is analyzed, and the impact of driving circuit parameters on short-circuit characteristics is presented. Compared to IGBT modules, SiC modules have higher di/dt and weaker ruggedness, so the conventional desaturation protection circuit cannot be directly used for SiC modules due to its relatively slow response. Thus we put forward a novel desaturation protection circuit, and present the comparison between the conventional protection circuit and the novel one. At last, short-circuit protection tests under typical hard switching fault and fault under load was conducted to verify the effectiveness of the novel desaturation protection circuit. The experimental results show that the novel desaturation protection method has a faster protection speed than the conventional one, and can ensure the reliable operation of SiC MOSFET power modules.