Common-Mode Noise Reduction for Bridgeless Flyback PFC Rectifier with Balance Technique

A novel bridgeless flyback power factor correction rectifier is proposed to reduce common-mode (CM) noise. The proposed rectifier realizes a symmetric configuration by placing a bidirectional switch between the equally split primary windings. To analyze CM noise propagation, highfrequency equivalent circuits with parasitic capacitances are derived. This study achieves the balance conditions in the equivalent circuit without additional inductors or capacitors. A 72-W prototype bridgeless flyback rectifier verifies a reduction in CM noise by maximum 35 dBμV at the frequency range of 150 kHz-30 MHz.