Modelling and Implementation of an Active EMI Filter for Conducted EMI Noise Reduction

Abstract

The analysis and design of an active electromagnetic interference (EMI) filter (AEF) for the reduction of conducted EMI noise in switched-mode power converters are presented in this paper. A brief overview of the many forms of AEF is provided. A voltage sensing voltage compensation (VSVC) type active EMI filter is implemented for a buck converter in PSIM software. This feed-forward filter can replace a conventionally used bulky passive EMI filter and can successfully reduce the EMI. The filter also does not affect the stability of the circuit. The filter is implemented for two types of circuits, i.e., for open loop as well as closed loop operation of buck converter. For the closed loop operation, a proportional integral (PI) controller is implemented. In these two instances, the properties and behavior of the VSVC-type AEF are studied and compared.