Online Gate Leakage Current Monitoring for SiC MOSFET Based on Average Gate Drive Current Extraction

Monitoring the gate leakage current is crucial for silicon carbide mosfets, as their gate structure is more fragile than that of Si-based devices. However, the existing gate leakage current monitoring methods still fail to simultaneously achieve high monitoring resolution and compatibility with a flexible gate drive structure. This letter proposes an online gate leakage current monitoring method for SiC mosfets based on the extraction of the average gate drive current. Compared with existing methods, the proposed method achieves a monitoring resolution at the submicroamperes level. For verification, the monitoring circuit is implemented in a high-frequency boost converter. The experimental results demonstrate that an acceptable relative error is achieved across the entire range of estimated gate leakage current, and that the proposed method does not interfere with the normal operation of the power converter.