Partial Discharge Testing Platform for High Voltage Power Module Packaging Under Square Wave Excitation

Abstract

Partial discharge (PD) issue of high voltage power module packaging insulation is increasingly critical due to the development of high voltage wide bandgap power modules towards high power density, which leads to smaller packages and higher operating voltages. However, existing standards for high voltage power modules focus on PD measurement under the sinusoidal waveform rather than actual DC or square waveform that poses actual electric stress on packaging insulation, and thus cannot fully represent the PD phenomenon in power electronics systems. To bridge this gap, this paper introduces a PD testing platform trimmed for high voltage power electronics systems, including a high-voltage (10 kV) square wave generator using supercascode structure with off-shelf SiC devices, and a contactless PD monitor using Super High Frequency (SHF) signatures from the PD event. The challenges in the design of this platform include the development of a PD-free high voltage square wave generator, and SHF PD signature separation from EMI noises induced by high dV/dt switching actions. Experiment validation is included in the last section of this paper.