MODELING WINDING LOSSES IN HIGH-FREQUENCY POWER INDUCTORS

A high-frequency model of iron-powder-core inductors is studied. The s kin and proximity effects that cause the winding parasitic resistance to increase with the operating frequency are considered. The inductor self-resonance due to the parasitic capacitances is taken into account as well. The frequency response of the inductor model is compared to that of an experimentally tested iron-powder-core inductor. Expression s giving the ac resistance as a function of the operating frequency ar e given. These expressions allow for an accurate prediction of the ind uctor power loss over a wide frequency range. The measured and calcula ted values of the inductor impedance magnitude and phase, the real and imaginary parts of the inductor impedance, the inductance, and the in ductor quality factor are plotted versus frequency and compared. Theor etical results were in good agreement with those experimentally measur ed. A design procedure for solid wire winding inductors based on the r esults of the inductor modelling is also given in the paper.