Common-Mode EMI Unterminated Behavioral Model of Wide-Bandgap-Based Power Converters Operating at High Switching Frequency

With wide-bandgap semiconductors increasing their commercial availability, high switching frequency operation has become an accepted practice to increase power density in power converters. High switching frequency operation, nonetheless, increases the electromagnetic interference (EMI) emissions of converters, for which accurate models are needed in order to predict their EMI noise and aid in the design of necessary filters. To this end, this paper assays first the impact that high switching frequency has on converter EMI emissions, and second, uses an unterminated behavioral model (UBM) to predict the common-mode (CM) emissions in the conducted EMI range (150 kHz-30 MHz). To achieve this, a new extraction procedure is developed for a UBM to effectively capture the rich high-frequency content of the CM emissions, providing a solution to the inherent limitations of previous behavioral models developed for insulated-gate bipolar transistor-based converters. The experimental results obtained with two setups: a 3-kW, 300-V dc, silicon-carbide-based three-phase inverter switching at 70 kHz and a 1-kW, 400-V dc, gallium nitride -based three-phase inverter switching at 500 kHz are presented to validate the approach and the model capabilities.