Partial Discharge Detection of High Voltage Wide-bandgap Semiconductor Module Based on Common Mode Fault Current

High-voltage and high slew rates in wide-bandgap (WBG) semiconductor devices increase the risk of partial discharge (PD) in insulating materials. Existing PD detection methods, such as Ultra-High-Frequency techniques, struggle to distinguish PD signals from interference caused by electromagnetic noise and rapid voltage transients. The optical method also has the limitation of being unable to detect internal faults within the module. This paper proposes a novel PD detection method based on common-mode current, enabling sensitive and undisturbed partial discharge detection inside the module. The innovation of this method lies in using the common-mode current generated by the charge leaving the system during the local discharge process as an indicator of PD. We validate the method using a $25 \mathrm{kV} / 16 \mathrm{~ns}$ fast-rise voltage power supply, demonstrating its effectiveness in detecting PD in WBG power modules. This approach offers a reliable solution for PD monitoring in WBG semiconductor modules.