Mitigating PWM-Induced Partial Discharge Through Optimized Skin Effect Control

This study investigates the influence of skin effect on partial discharge (PD) in power electronics and explores mitigation strategies to enhance system reliability. The highfrequency components in Pulse Width Modulation (PWM) signals, caused by rapid voltage transitions, significantly influence electrical properties such as the skin effect. This phenomenon concentrates current density near conductor surfaces, leading to localized heating and increased electric field stress, which can initiate PD, a localized electrical breakdown within the insulation that compromises its integrity. The study hypothesizes that reducing the voltage pulse slew rate diminishes the skin effect by promoting a more uniform current distribution, resulting in a more even electric field distribution. This increases the partial discharge inception voltage (PDIV) and reduces PD magnitude at a given voltage. Furthermore, the study examines the impact of conductor sizing, finding that narrower conductors reduce the skin effect by promoting more uniform current distribution. Consequently, thin conductors lower PD susceptibility, particularly at dielectric interfaces within connectors. A novel approach combining reduced slew rate and optimized conductor thickness is proposed and validated through both COMSOL finite element analysis (FEA) simulation and experimental measurements, offering insights for designing power electronics systems with improved resilience against PD and enhanced operational lifespan.