PCB Winding Coupled Inductor Design and Common-Mode EMI Noise Reduction for SiC-Based Soft-Switching Three-Phase AC–DC Converter

Abstract

This article presents a PCB winding coupled inductor design for both high efficiency and effective common-mode (CM) noise reduction in a silicon carbide (SiC)-based soft-switching three-phase ac–dc converter. A balance technique is applied to reduce the CM noise, creating a return path with additional inductors. The inductors in the main circuit and return path are coupled in one core and implemented with PCB windings. A winding interleaving structure with strong coupling between the main inductors is selected to minimize the winding loss and to improve the converter efficiency; however, the interwinding capacitance brought on by the winding interleaving worsens the CM noise. An inductor model including the capacitance is introduced, and its impact on the CM noise is analyzed. A novel inductor structure is proposed to scale back the interwinding capacitance and to enhance the CM noise reduction capability. Experiments with a SiC-based 25-kW soft-switching three-phase ac–dc converter prototype validates the performances of the proposed PCB winding coupled inductors.