Design of active EMI filter based on virtual impedance transform method

This paper presents a equivalent impedance transforms method to design the active electromagnetic interference filter (AEF) for power circuit application. The proposed filter is analyzed by using a simple block diagram manipulated in the present paper. From the analytical results, the influence of the circuit parameters on the virtual impedance effects is clarified to establish the design method. To confirm the effectiveness of the method, some results of basic experiments are included. This method allows filter circuits with insertion loss and impedance compensation higher than previously reported to be built. The effectiveness of the proposed circuit has been verified by experimental results.