A New Integrated Active EMI Filter Topology With Both CM Noise and DM Noise Attenuation

Integration of electromagnetic interference (EMI) filters is a good idea to further decrease the volume and weight of a power converter. However, the conventional research articles mainly focus on the integration of passive components or planar printed circuit board structures. This article proposes a new integrated active EMI filter (AEF) topology. It can attenuate both common-mode (CM) and differential-mode (DM) noise at the same time. Different from the traditional discrete CM AEFs and DM AEFs, noise sensing and cancelation of this proposed topology are performed simultaneously. The working principle and special features of this topology are analyzed in detail. Based upon the theoretical analysis, the insertion loss of this integration topology is close to the traditional separated CM AEFs or DM AEFs. Besides fewer components and dc power supply are demanded. A prototype is built and tested through experiments. Experimental results derived on standard test board and practical converter show good agreement to theoretical analysis.