Short-circuit protection method for medium-voltage SiC MOSFET based on gate–source voltage detection

Abstract

During the short-circuit fault of a two-level bridge converter based on silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors (MOSFETs), the SiC MOSFETs may fail within a few microseconds without short-circuit protection. The short-circuit protection of SiC MOSFETs is an essential feature for improving the reliability of converters. This study proposes an improved short-circuit protection method for medium-voltage SiC MOSFETs subjected to shoot-through conditions. In the protection method, the gate–source voltage of the SiC MOSFETs in a half bridge is detected to determine whether a shoot-through short circuit occurs or not. A desaturation protection circuit based on VDS measurement for a short circuit is also designed for overcurrent. The protection circuit’s validity is verified by the experimental results. Compared with conventional commercial driver integrated circuits, the proposed method can detect and turn off SiC MOSFETs in 0.2 μs under the shoot-through condition. Desaturation protection can be completed in 0.5 μs when overcurrent occurs.