Characterization and Modeling of Hysteresis for Magnetic Materials Used in EMI Filters of Power Converters

The magnetic material when designing EMI filter determines the inductance value and the parasitic elements that influence the insertion loss effectiveness of the filter. Moreover, the EMI filter characterization is usually realized at low power levels (low current and low voltage). When the EMI filter is subjected to higher currents through its coils, the principal characteristics of the filter (inductance variation with current and frequency) are modified. To account for these variations in the design step, it is useful to take into account the hysteresis model that represents the inductive and dissipative effects. Therefore, in this paper, an approach combining a magnetic hysteresis model together with a concept of material capacitance is proposed. The model is identified from a single turn of flat copper ribbon (STFC) experimental setup. Then, the experimental data are modeled with the proposed hysteretic and capacitive material behavior model (HCM) that is implemented in an equivalent circuit modeling approach, accounting for both the magnetic behavior law together with the “material capacitance.” The robustness of the proposed approach is evaluated by comparison and validation with the experiment results, showing good representation of the inductive and partially the dissipative effects.