An improved foster model of common-mode inductor and its application in EMI filter design

摘要

The high-frequency characteristics of the common-mode inductor greatly influences the performance of Electromagnetic Interference (EMI) filters. In order to design an effective EMI filter, it is necessary to accurately model the common-mode inductor. This paper proposes an improved Foster model, which can more fully model the common-mode inductor, especially in the high-frequency range. Analysis and parameters of the model are provided. The curve fitting of impedance for the proposed model is compared with that of a traditional one. By applying this technique to an EMI filter design for a 2.4 kW Power Factor Correction (PFC) motor driving supply, experimental results validate the feasibility of the improved Foster model.