Circuit simulation model for ferrite core inductor taking into account dynamic magnetic loss

The purpose of this study is to develop a precise-loss circuit simulation model for ferrite inductors and transformers used in power converters. The power loss in ferrite is mainly due to the magnetic losses of hysteresis and dynamic magnetic losses. The B-H loop becomes narrower with decreasing excitation frequency. However, even at frequencies lower than 1 kHz, the B-H loop exhibits a certain minimum width. This loop is referred to as the DC hysteresis loop or simply the hysteresis loop. The dynamic magnetic loss is obtained by subtracting the hysteresis loss from the B-H loop area measured at a frequency above 1–10 kHz. Magnetic field intensity, Hf, causing the dynamic magnetic loss is defined as (dB/dt)A, f, where kf is the dynamic magnetic loss parameter. Hf is obtained as a function of B and dB/dt from the measured B-H loops under rectangular waveform voltage excitation. Using the Hf data, we simulated B- H loops under sinusoidal waveform voltage excitation where the instantaneous value of dB/dt changes at every moment in time. The simulated and experimental results were in good agreement. The results of the present study contribute to the development of a precise-loss nonlinear simulation circuit model for ferrite-applied magnetic devices. The model can be used in the design of power electronics.