Search

Bond wire fault is one of the most prominent degradation types for silicon carbide (SiC) mosfets, which could be detected and monitored through appropriate precursors. In this article, an online bond wire fault monitoring method for SiC mosfets with Kelvin package is proposed. It is based on the fact that the bond wires parasitic inductances are affected by bond wire fault over time. The variations of parasitic inductances can be converted into the variations of the voltage ringing between the Kelvin source and power source (vKS-S) during the turn-on event. To eliminate the affecting factors, the voltage ringing of the circuit parasitic inductance (vCIR) is introduced, and the division of the peak values of the two voltages ringing is used as the new bond wire fault precursor. The study results indicate that the proposed precursor has high sensitivity and high resolution to monitor each bond wire fault. Besides, the monitoring results are not affected by factors such as junction temperature, load current, and bus voltage. Therefore, the proposed fault monitoring method can be implemented online without knowing the factor information. The confirmatory experiment is carried out to verify the correctness of the proposed method.