Analysis of Common-Mode Noise and Design of a Reduced-Volume Concentric Choke for Dual Active Bridge dc-dc Converter with Integrated Magnetics

Dual active bridge (DAB) dc-dc converter with integrated transformers is explored in recent years due to its advantages such as low component count, high power density, and high efficiency. Although the operational performance of the DAB converter is well reported, the common-mode (CM) noise with the integrated transformer is yet to be thoroughly analyzed. Hence, this article presents a detailed analysis of the CM noise performance of the DAB converter employing an integrated transformer. Moreover, the conventional CM chokes incorporated to mitigate the CM noise cause a deleterious impact on the volume and power density of the converter. This article proposes a concentric CM choke that occupies less volume compared to its equivalent conventional CM choke of the same CM impedance. The analysis and design guidelines for the proposed concentric CM choke are presented. The above-mentioned analyses of the integrated transformer and the concentric CM choke are experimentally validated on a DAB converter prototype.