Improved Balance Technique for Common-Mode Noise Suppression of PCB-Based PFC

Abstract

Symmetry and cancellation techniques are often employed to suppress common-mode (CM) noises in switching power converters. In addition, shielding technique (Fei <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> , 2018) has been demonstrated effectively to suppress CM noises for isolated converter with PCB-based transformer design. However, for nonisolated converters, such as power-factor correction circuits, none of the techniques mentioned above is deemed applicable or justifiable. Recently, the balance technique has been demonstrated effectively to suppress CM noises up to a point where the parasitic ringing between the inductor and its winding capacitor is observed (Wang <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">et al.</i> , 2007), (Yang, 2018). This article presents an improved balance technique in a PCB-based coupled inductor design that compensates the detrimental effect of the interwinding capacitors. In the given example, CM noise suppression is effective in the frequency range of interest up to 30 MHz. A CM noise model is established to substantiate the measurement results.