A study of an active EMI filter for high current ACDC converter

With the requirement of high power density converters, the volume of the EMI filter needs to shrink as much as possible. This paper studies a super small volume and high insertion loss active EMI filter. Firstly, a high current and high efficient AC-DC converter is analyzed. The CM interference is predicted precisely. Secondly, traditional active EMI filters are analyzed by calculating. A high performance active EMI filter without magnetic components that suppresses the common mode interference in the output side of the AC-DC converter is designed. Finally, the high current AC-DC converter as well as the proposed active EMI filter prototype is built. Simulation and experimental results demonstrate the efficiency and stability of the proposed active filtering method.