SiC MOSFET Degradation Monitoring based on Source Inductance Voltage

Condition monitoring (CM) is effective in ensuring the safe operation of SiC MOSFETs. Currently, very few CM methods can provide comprehensive monitoring capabilities, that cover all key degradation mechanisms with only one health indicator. This paper proposes a complete online CM method for SiC MOSFETs based on the voltage oscillations at source inductance during the device turn-on transients. The relationship between the peak positive voltage oscillation and gate oxide and bond wire degradation mechanisms is investigated. The monitoring circuit includes a peak detector and a reset signal generator. Compared with the existing methods, the proposed method provides dual monitoring of gate oxide degradation and bond wire fatigue without the need for complex measurement systems. Experimental results show that the oscillation peak is reduced by 21.2% and 5.0% after high-temperature gate bias and power cycling tests, respectively. Therefore, the proposed method offers a promising tool for continuous online monitoring in SiC-based applications.