Short Circuit Protection of SiC MOSFET Module with Extended Short Circuit Withstanding Time

Abstract:
The short circuit protection of SiC MOSFETs is one of the most critical challenges that need to be overcome for these devices to be widely deployed in power converters. This paper proposes a centralized two-step protection method to achieve fast and noise-immune protection during the short circuit. Firstly, the short circuit current that returns to the bus capacitor is detected and the gate driving voltage is reduced to a lower value to increase the short-circuit withstanding time. Secondly, the phase leg output voltage is sensed and corresponded with a pre-set range to further verify the short-circuit fault. If confirmed, an error signal is generated to turn off the power devices. Compared with state-of-art protection methods which locally turn off the power device, the proposed method features centralized protection, ultra-fast response, and high noise immunity capability. Experimental results confirm the excellent performance of the proposed protection scheme.