Improved Inductance Calculation in Variable Power Inductors by Adjustment of the Reluctance Model Through Magnetic Path Analysis

This article presents a study to improve the inductance calculation of magnetic components in power converters, of particular interest, in the case of applications using variable inductors. In order to increase the accuracy of the estimation of the reluctance paths, several factors have been taken into consideration, such as the permeability definition under saturation, the temperature effect on the magnetic material behavior, and the distribution of saturated regions in the magnetic core. The methodology of the present study is to compare the analytical models derived from circuital equivalents against finite-element analysis numerical techniques, in order to validate the proposed model of a variable inductor, including the effects of the mentioned factors. The proposed model is then compared with experimental measurements to prove its validity. Finally, a design example for the variable inductor is presented.