Nonlinear Field Dependent Conductivity Materials for Electric Field Control within Next-Generation Wide Bandgap Power Electronics Modules

We are witnessing an excitement in the research community to develop next-generation wide bandgap (WBG) power electronics. The superior characteristics of WBG materials regarding their operational capability at higher voltages, temperatures (200°C) and switching frequencies in comparison with commercial Silicon devices, has made them auspicious materials for the future power electronics. Increased voltage blocking capability and at the same time, an interest in high-power density designs can enhance the local electric field, in particular, at the edges of the metalized substrate. The increased electric field can become large enough to lead to severe partial discharges (PDs) within the module and thus the failure and reduction of the reliability of the insulation system. This paper shows that applying nonlinear field dependent conductivity (FDC) materials as a coating applied to highly stressed regions combined with a protruding substrate design can well address high field issue within high-voltage high-power-density modules.