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Reducing High Frequency CM Noise in Balanced PFC

CPES has proposed the balance technique to reduce CM noise. For a boost PFC converter, low frequency CM noise can be significantly reduced with small modification to the circuit. Lower low frequency CM noise results in higher corner frequency of EMI filter, which means smaller CM choke for low frequency noise attenuation. However, high frequency CM noise remains a challenge and extra efforts and components are needed in the EMI filter to suppress the high frequency noise peaks. High frequency model is built to study the high frequency CM noise of balanced PFC converter. Analysis on the model provides guideline to reduce the high frequency CM noise emission so that EMI filter design becomes easier.