Insulation Capability at 10 kV, >300 V/ns of a Nonlinear Resistive Polymer Nanocomposite Field-Grading Coating in a 15-kV Silicon Carbide Module

Emerging medium-voltage silicon carbide devices offer the potential to achieve more efficient and compact power electronics for grid-tied applications. However, the lack of an effective insulation solution for packaging the devices has slowed their widespread adoption. Recently, a nonlinear resistive polymer nanocomposite coating has been introduced to enhance the insulation by reducing localized electric field stress inside the modules. The purpose of this study is to evaluate the insulation capability of the polymer nanocomposite under high <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dv/dt</i>. Half-bridge modules of 15-kV silicon carbide devices were packaged with the nanocomposite coating at the triple points on the module substrate. All the modules were tested free of partial discharge at 20 kV for 1 min. One module underwent a repetitive double-pulse test at 10 kV, 2 A and was switching at a peak <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dv/dt</i> > 300 V/ns. These findings further support the coating's potential as a viable practical solution to the insulation challenge of medium-voltage power modules.