Comprehensive Analysis of Coupled Inductors with Powder Cores Used in Interleaved Converter: Measurement, Modeling, Design Methods, and Experimental Evaluation

Abstract

One of the best techniques for downsizing power converters is to use coupled inductors in multiphase circuits. Meanwhile, from a magnetic material perspective, powder core material is well known as an attractive magnetic material with superior features such as high saturation flux density. However, since the relative permeability of power cores depends on the magnetic field intensity, designing coupled inductors is difficult, and the modeling method is not well discussed in the relevant literature. The purpose of this research is to model coupled inductors with powder cores and present a simple magnetic design method. A model of coupled inductors is created by a novel measurement method of the dc superimposition characteristic unique to the coupled inductor of two-phase interleaved circuits. Furthermore, a design method based on a theoretical analysis using a magnetic circuit model had been established. The validity and effectiveness of the proposed methods are confirmed from simulation and experimental tests. This research is helpful in the field of the model-based development of coupled inductors.