A Novel Magnetic Equivalent Circuit Model for the Corner of Inductor Core

Abstract

The accurate calculation of inductance is the most basic problem of inductor design. Based on finite element method (FEM) analysis of the flux density distribution in the corner of the core, a local corner magnetic equivalent circuit (MEC) model is proposed for a core-type inductor. In this model, the corner is divided into three parallel branches, and the joint part of the corner and the core limb are divided into two branches, one of which is continuously divided into three branches. In addition, a flux leakage branch of the core window inner corner is modeled. These branches form a local corner MEC by series and parallel to describe the flux distribution of the corner. The calculation results show that, in the local corner MEC model, the core flux density distribution is consistent with the FEM simulation. The maximum relative error of the inductance is less than 6% and the average relative error is less than 4% compared to the physical prototype measured data with the range of current from 20 A to 1000 A, which shows that the local corner MEC model has a high accuracy inductance calculation.