Mirror Source based Overcurrent and Short Circuit Protection Method for High Power SiC MOSFETs

This paper presents a fast overcurrent and short circuit protection based on the mirror source detection method for 1200V/1200A Silicon Carbide (SiC) MOSFETs used in a high power Dual Active Bridge (DAB). It will be shown that this protection method is feasible for a low inductive short circuit caused by a half bridge shoot through, a high inductive short circuit based on a failure inside the load as well as short circuits of Type 1 or hard switching fault. Additionally, the short circuit behaviour is analyzed for different junction temperatures of the MOSFETs. Experimental results proof that using the investigated method always ensures the operation in the Short Circuit Safe operating Area (SCSOA) of the MOSFET after triggering short circuits.