Modeling of Saturable Inductors for Application in DC-DC Converters

This paper deals with a method by which the experimental characterization of a power inductor is obtained from onboard measurements that exploits a low-cost DC-DC buck converter to supply the inductor under test with quasi-rectangular voltage waveforms of different amplitudes and bias conditions. The measurements of the voltage $v_{\mathrm{L}}(t)$ across the inductor and the current $i_{\mathrm{L}}(t)$ are performed up to inductions approaching the magnetic saturation. After suitable integration of $v_{\mathrm{L}}(\mathrm{t})$ , the magnetic flux is obtained as a function of $i_{\mathrm{L}}$ and the accuracy of the described identification process is checked by comparing the measured waveform of the current to numerical simulation of the same quantity obtained assuming as input the DC current component and the measured voltage waveform.