Frequency-Dependent Inductance Model and Field-Circuit Equivalence Principle Based on Maxwell's Equations

With the increasing switching speed of power devices, more severe high-frequency EMI issues arise, drawing growing attention to the high-frequency impedance characteristics of filters. Traditional inductance model based on magneto-quasi-static (MQS) field, lacking a physical description of high-frequency characteristics, are no longer able to accurately simulate these features. Therefore, this paper proposes a frequency-dependent inductance model based on Maxwell's equations and provides a detailed analysis of the equivalence process from fields to lumped circuit. The model not only reveals the physical mechanisms of inductive resonance but also provides theoretical support for the selection of the magnetic cores within the conducted EMI frequency range.