Conference PaperComparison of Electric Field Suppression Techniques in (U)WBG Power Modules Under Unipolar and Bipolar Square Voltages at Varying High FrequenciesAdhikari, Pujan [The University of Texas at Dallas,Department of Electrical and Computer Engineering,Richardson,TX,USA]; Ghassemi, Mona [The University of Texas at Dallas,Department of Electrical and Computer Engineering,Richardson,TX,USA]Most research involving resistive field grading materials or nonlinear field-dependent conductivity (FDC) layers has predominantly concentrated on DC or sinusoidal AC voltages, even though (U)WBG power electronic modules typically operate under high-frequency square wave voltages. To bridge this existing research gap, the present study systematically investigates the efficacy of an FDC coating in alleviating electric field stress when subjected to high-frequency, high-slew-rate square wave voltages. The findings indicate that applying a nonlinear FDC layer significantly reduces electric field stress, even under stringent conditions involving elevated operating frequencies. Furthermore, the influence of the square wave voltage type—the distinction between unipolar and bipolar square waveforms—on electric field stress remains inadequately understood despite substantial progress in breakdown and PD experiments related to these phenomena. Consequently, this study undertakes a comparative analysis of nonlinear FDC layers' performance under unipolar (+27.5 kV) and bipolar (±27.5 kV) square wave voltages. In doing so, this investigation contributes valuable insights into the interplay between high-frequency operation, the polarity of square waveforms, and the efficacy of nonlinear FDC layers in mitigating electric field stress within (U)WBG power module packages.IEEE2025-08-24106528841 to 7https://doi.org/10.1109/SDEMPED53223.2025.111543132306093Dallas, TX, USANational Science Foundation