A Multi-Channel Active Common-Mode EMI Filter with Enhanced Suppression and Component Reuse for Boost Converter Applications

Abstract

Cascaded active EMI filters offer superior suppression performance compared to single-stage filters, but the required number of components increases proportionally with the number of stages, resulting in larger volume and higher cost. To address this issue, this paper proposes a multi-channel active common-mode EMI filter based on magnetic core and chip reuse. In the proposed structure, multiple cascaded filter modules share a single current-sensing magnetic core, effectively reducing the number of magnetic components and lowering both hardware cost and structural complexity. Additionally, by employing a dual-channel high-speed operational amplifier (AD826), the design enables chip-level reuse in the signal amplification stage, further improving integration and compactness. A dual-feedback cascaded architecture is adopted to enhance common-mode EMI suppression without significantly increasing hardware resources. Experimental results based on a boost converter platform validate the effectiveness of the proposed filter in achieving both high suppression performance and efficient component utilization, making it well suited for power electronic systems operating in complex electromagnetic environments.