Simple Analytical Models to Predict Conducted EMI Noise in a Power Electronic Converter

Knowing the characteristics of the sources and paths involved in the injection of conducted electromagnetic interference (EMI) currents into the input source from a power converter allows one to analyze and improve a converter's electromagnetic compatibility (EMC) performance. In this paper, analytical models to predict the conducted EMI noise generated by a boost power factor correction (PFC) converter are presented. These simple models are based on the noise generation mechanism and the path through which the noise travel. The models require the measurement of high frequency characteristics of the components involved in the noise path. By comparing the predicted noise spectra with the experimentally measured noise spectra, it is verified that the proposed analytical models can be used to reasonably predict the noise generated by the PFC. The proposed models can thus be used to carry out a preliminary design of the EMI filters needed and hence their size and cost even before building and testing the power converter.