A Novel SiC MOSFET Short‐Circuit Protection Method Based on the Gate Charge Characteristic Curves

ABSTRACT The SiC MOSFET is widely used in high‐voltage, high‐frequency, high‐efficiency, and high‐temperature applications due to its excellent material properties. However, due to its weak short‐circuit (SC) tolerance, an effective SC protection circuit is essential. Conventional SC protection methods rely on direct or indirect measurements of the drain‐source voltage or drain current. However, they face difficulties in achieving both fast response and reliable protection, since they cannot distinguish between different SC types or provide specific turnoff protection actions. Therefore, this paper proposes a novel SC protection method based on the gate charge characteristic curves. By considering the differences in the gate charge characteristic curves of the SiC MOSFET under different SC conditions, reference values are selected to identify the SC types. The specific turnoff protection actions are further implemented based on the identified SC types. When the hard switching fault (HSF) occurs, the proposed method can detect the SC condition and immediately trigger protection action when the SC current is relatively small; when the fault under load (FUL) occurs, the proposed method can accurately identify the SC type and employ a soft turnoff approach to turn off the SiC MOSFET, thereby avoiding a significant drain‐source voltage spike. Experimental results show that the proposed method can accurately identify different SC types. Compared with the most commonly used desaturation detection method (the blanking time is 1 μs), the protection time and turnoff losses are reduced by 78.8% and 53.2% under the HSF, respectively. When the FUL occurs, the proposed method reduces protection time by 31.7% and reduces drain‐source voltage spike by 9.6%, thereby enhancing the reliability of protection actions.