By utilizing wide-bandgap power devices, converters can operate at high switching frequency to increase power density without sacrificing efficiency. However, conducted electromagnetic interference (EMI) poses a challenge in the design of these high-frequency power converters. Common-mode (CM) noise is especially difficult to model and diagnose because it is determined by small distributed parasitic capacitances. This work evaluates the limitations of existing techniques to measure parasitic capacitances in power converters. Then, a new technique is presented which accurately quantifies the parasitic capacitances affecting CM noise based on conducted noise measurements. These capacitance values can be used to accurately model the CM noise behavior under different operating conditions.
