Effects of mix-mode noise emissions on the design method of power factor correction boost rectifier EMI filters

In this paper, effects of the recently found mix-mode (MM) conducted electromagnetic interference (EMI) noise emissions on the boost-type power factor corrected (PFC) pulse-width modulated (PWM) rectifier are first introduced. A practical PFC EMI filter design method with consideration of the MM emissions is given. The proposed method can be easily implemented in commercially-available EMI filter by means of the differential-mode (DM) base line noise emission measurement with a MM emission current-dividing capacitor. Incorporation of MM EMI considerations in a filter design of the PFC stage could be a better choice from the filter size reduction, high power density and high efficiency of the whole system points of view. Design examples are presented and experiments are carried out to verify the analysis. Based on the theory of MM EMI emissions, the effects of the boost PFC inductor on EMI filter effectiveness are then studied along with experimental verifications.