Common-Mode EMI Noise Reduction for Interleaved Multichannel GaN-Based PFC Converter
To enhance the high-frequency balance in a PFC converter, a novel PCB winding structure with an integrated coupled inductor is proposed. A CM-noise model and balance conditions for minimizing CM noise is derived. Moreover, ground loop impacts for high-frequency noise are studied.
A two-phase, interleaved totem-pole PFC converter with GaN device (1-3 MHz switching frequency) is built up to verify the pro- posed balance inductor structure. Two balance inductors are introduced in the return path for CM noise reduction. All four of the in- ductors in the PFC circuit are integrated into a single EI magnetic core with six layers of PCB windings. Experimental results show that balance conditions are achieved in the whole interested frequency range (150 kHz30 MHz) with 20 dB uniform CM noise reduction. At the same time, resonant frequency due to ground loop is increased beyond 30 MHz so that the ground loop impact in the interested frequency range is eliminated.