Effects of Rise Time and Pulse Width on Magnitude and Phase Distribution of the Partial Discharge in PowerModule Packaging Insulation under Square Pulse

As high-voltage power modules are applied widely, the partial discharge (PD) occurring in the packaging insulation under high-voltage square pulse becomes the main issue resulting in power module failure. Varying pulse widths and rise times are prominent characteristics of the square pulse, which are also factors affecting PD behaviors. Focusing on the effect of square rise time and pulse width on PD behaviors, a specially designed down-mixing PD detection method is applied. The PD experiments under the square pulse of different pulse widths and rise times are carried out. The statistics of PD magnitudes indicate that a longer rise time leads to a declining trend of PD magnitude and a lag tendency of the occurrence phase, which can be explained based on the initial electron appearance delay and the PD occurrence process. During the rising edge, pulse width affects little on the PD behaviors while at the falling edge, the PD magnitude shows an increasing trend and the occurrence phase shows a shifted tendency as the pulse width becomes longer.