Influence of switching frequency and saturation of the magnetic material on the volume of common-mode inductors used in power converter EMI filters

The subject of this paper is to propose a new design method of EMI filters that allows to minimize the volume of the common-mode inductor with consideration of core saturation issues. One of the main results of this study shows the impact of the switching frequency on the filter insertion loss and the volume of the coupled common-mode inductor depending on the length of the shielded cable. Then, the relationship between switching frequency and optimum inductor volume is investigated. Obtained results show that, depending on the cable length, an optimal switching frequency that allows to minimize the inductor volume can be determined.