Modeling and Prediction of Common Mode Electromagnetic Interference in GaN-Based Switching Power Converters

Behavioral models of common mode (CM) electromagnetic interference (EMI) are proposed herein for a GaN high-electron-mobility transistor (HEMT) synchronous buck converter. First, a CM noise model is developed using a linear equivalent circuit that consists of a voltage source, current source, and two noise impedances. The behavioral parameters of the CM model are then extracted by changing the input-side shunt impedances. A GaN HEMT buck converter setup is then built using switching frequencies of 100 kHz, 200 kHz, and 500 kHz to verify the validity of the CM EMI behavioral model. A comparison between the experimental and predicted results indicated that the proposed CM EMI model of GaN-based power converters was able to predict well the CM EMI current in the 150 kHz–30 MHz frequency range.