A new active EMI filter with virtual impedance enhancement

In this paper, a novel topology and control scheme for active electromagnetic interference (EMI) filter based on the idea of virtual impedance enhancement is proposed. To ease analysis, a general and simplified equivalent circuit is introduced to predict the conducted emissions incurred from switched-mode power converters. In addition, theoretical analysis is given to show how the proposed active EMI filter (AEF) should be designed along with simulation validation. A prototype of proposed AEF is implemented and tested to verify its effectiveness on proof-of-concept test setup. It is shown that the proposed AEF is capable of attenuating conducted emissions.