Effect of Interphase Dielectric Property in Electric Field Distribution in Silicone Elastomer Nanocomposite

The emergence of ultra-wide bandgap (UWBG) devices results in increasing research in high-density and high-temperature power electronic (PE) packaging. Encapsulants are crucial for electronic packaging and are required to be functional at high-density, high temperatures in UWBG-based power electronic devices. Silicone (Si)-based gels and elastomers, popularly used as encapsulations in conventional power electronic packaging, show dielectric issues under high-density and high-temperature systems. The local electric field enhancement at triple points in the high-power density PE devices increases the risk of partial discharge (PD). Adding nano-fillers in Si-based elastomers is one of the approaches to increase the dielectric integrity of high-power density devices. The high-volume fraction of interphase between the nanoparticles and polymers improves the dielectric properties. The interphase power model relates the dielectric constant of polymer composites with the dielectric constant of the interphase layer. In this paper, a numerical study has been conducted to investigate the effect of interphase dielectric constant on the electric field mitigation at the triple points Si-elastomer-based nanocomposites. A numerical model is developed in COMSOL Multiphysics to investigate the effect of interphase dielectric property on electric field distribution in the encapsulant of PE modules. Furthermore, the effect of nano-filler dielectric properties in minimizing the local electric field is compared.