Hard-less common mode active EMI filter

Active EMI filters appear as an alternative to classical EMI filters based on passive components. Active EMI filters can provide more compact, cheaper and lighter solutions than passive approach. In this paper we present a theoretical analysis of the 4 possible configurations. Expressions of the transfer function and insertion losses considering impedances of mains and source of noise are presented. The voltage-current topology is identified as the more convenient solution. Finally, preliminary experimental results of a prototype capable to provide attenuation up to 100MHz are shown.Peer Reviewe