Adaptive Current Threshold for Rapid Short-Circuit Protection of SiC MOSFETs

Due to the limited short-circuit (SC) withstand time of silicon carbide metal-oxide-semiconductor field-effect transistors (SiC MOSFETs), their reliable operation requires fast SC protection. This paper proposes an ultrafast SC protection method for SiC MOSFETs. This method leverages the characteristic of the load current to remain continuous throughout the converter operation, enabling the adaptive adjustment of the SC detection threshold. Unlike traditional methods that utilize a fixed threshold to detect fault currents, the proposed adaptive threshold strategy allows for dynamic adjustments according to the load current level, thereby improving the detection speed across all types of SC faults. The circuit structure and design considerations for implementing this strategy are discussed. Experimental results under 450-V multi-pulse testing and half-bridge inverter operation demonstrate the effectiveness of this SC protection method. The detection speed is significantly improved compared to the traditional current detection method and the desaturation detection method.