Investigating Partial Discharge Mitigation at the Triple Point Interface in Power Modules

Abstract

Advancements in power electronics, particularly new semiconductor technologies like Wide Bandgap (WBG) and Ultra-Wide Bandgap (UWBG) materials, enable higher power levels. This drives the need for improved insulation materials to handle increased electrical stress. With higher power levels, issues arise at the triple junction interface (dielectric – conductor - substrate), where strong electric fields are concentrated. This phenomenon increases the probability of partial discharges, which can degrade insulation. The challenge is to investigate and statistically compare different materials at this critical interface. This study aimed to develop a controlled experimental setup that accurately simulates the triple junction, enabling a systematic evaluation of electrical strength and partial discharge inception voltage across various potting compounds. Based on the research, field-dependent conductivity composite and field-dependent permittivity composite were prepared, and their effect on the inception voltage was investigated.