Conductive Noise Suppression with Canceling for Miniaturization of EMI Filters in PFC Converter

This paper presents the reduction methods of conductive noise applied to Power Factor Correction (PFC) circuit. This is to generate a voltage of the opposite polarity simultaneously with the switching operations, and to inject a compensation current for the leakage current. This paper proposes two noise-canceling methods which are a fixed wave compensation method and a switching waveform tracking method. The fixed wave compensation method is effective for reducing the average (AV) value of the conductive noise. On the other hand, the switching waveform tracking method is effective for reducing both the AV value and the quasi-peak (QP) value. The switching waveform tracking is realized by injecting a compensation current proportional to dv/dt in the switching operation by a current mirror circuit. The results of experiments on each method are reported.