Electric Field Control by Nonlinear Field Dependent Conductivity Dielectrics Characterization for High Voltage Power Module Packaging

Accelerated aging in next-generation insulation systems for wide bandgap (WBG) power electronic modules is the most significant barrier to realizing high-voltage, high-power-density conversion devices and systems. Accelerated aging in these systems is the result of two factors: 1) voltage pulses faster (with a dv/dt up to 100 kV/μs) and more repetitive (with a frequency up to 500 kHz), and 2) electric field stress higher than that found in existing state-of-the-art technologies. Current geometrical techniques for electric field control in power modules cannot address this issue alone. Our goal in this paper is to characterize nonlinear field-dependent conductivity (FDC) materials applied to high electric stress regions that, in combination with geometrical techniques, can well address high electric field stress issue. Studies are carried out in COMSOL Multiphysics. The influence of applied voltage type, AC and DC, is investigated. It is shown that a bridging FDC coating layer can lead to more electric field reduction than non-bridging one.