Nonlinear magnetic ring model based on impedance measurements with DC-bias current

This paper presents a complete method for modeling nonlinear magnetic rings that captures frequency dependence, losses (hysteresis effect), and nonlinear effects including saturation. The approach relies on frequency-domain impedance measurements (here, 10 Hz – 10 MHz) under DC bias currents up to saturation (here, 800 A), and extends classical equivalent-circuit fitting to a two-dimensional impedance function of frequency and current. A key contribution is the formulation of a fully implementable modeling framework together with its realization as SPICE netlist code, enabling direct time-domain simulation under arbitrary excitation signals. The validity of the model is demonstrated through analytical verification, impedance measurements with DC bias, and high-current experiments. Furthermore, the paper investigates and discusses the applicability of the model, showing consistency with results obtained from a dedicated high-current test setup. The outcome is a novel, practical, and fully validated nonlinear modeling methodology, with its implementation released as SPICE code.