Common mode current prediction from a power converter with attached cables based on a terminal equivalent circuit model

Abstract

An equivalent two terminal model based on Thevenin equivalents describes the common mode currents on the input and output side of a buck converter. A linear equivalent terminal model of the buck converter is created based on measured common mode currents for various common mode loads up to 300 MHz. The results using the terminal model agree well with the measurements for common mode load values that are within the range used for creating the terminal model, however, for loads far away from the characterization load range larger differences occur, as the power converter is a non linear circuit which is modelled by a linear equivalent circuit.