Phase-Resolved Partial Discharge Analysis of Power Electronic Module Packaging under High dV/dt Square Pulse Voltage

Generally, the power module operates under high dV/dt square pulse wave, the partial discharge (PD) is one of the main issues resulting in its packaging insulation failure. Phase-resolved partial discharge (PRPD) analysis is an important and effective method to explore PD characteristics, however, the characterization of PRPD under square pulses is rarely studied. Since most PDs under high dV/dt square pulse occur at the voltage transition moments, this study explores the PRPD analysis of power module packaging insulation during voltage transition moments of high dV/dt square pulse. The PD data under the square pulse of different voltage transition times are collected, the phase distributions of PDs at the rising and falling edges are counted, and the effects of voltage transition time on the phase distribution are compared and analyzed. Besides, the probability density analysis is performed based on the phase distributions, and the results show that the phase distribution at the rising edge of the square pulse conforms to the normal distribution, while that at the falling edge conforms to the Burr type XII distribution. As the voltage transition time increases, the mean of the PD phase distribution shows a lagging trend and the dispersion of the phase distribution increases.