Mitigating Partial Discharge Caused by Steep Voltage Pulses at High Temperatures

Electrets are dielectric materials that generate electric fields without a voltage source. Our previous studies reported how one could design, fabricate, and utilize electrets to neutralize locally concentrated high electric fields and mitigate partial discharge (PD) in power electronics systems. While the polymer-based electrets used in our prior work demonstrated impressive performance in reducing PD magnitude and rate under recurring, steep voltage transients, the low operating temperature of these materials remained a significant challenge. In this study, we report that inorganic thin film electrets can mitigate PD at high temperatures. This article reports PD measured under steep square voltage pulses with slew rates as high as 75 V/ns and at temperatures as high as 245 °C. The results demonstrate that the inorganic thin film electrets can decrease PD magnitude and increase PD inception voltage (PDIV) in harsh electrical and thermal conditions.