Evaluation of Permanent Magnet Distribution Schemes for Toroid Power Inductor with Increased Saturation Current Using 3D Physical Models

摘要

Effects of different permanent magnet (PM) distribution schemes on the saturation performance of a permanent magnet toroid power inductor are presented and evaluated in this paper. By appropriately placing the PM in the gap of the power inductor, the flux induced by the winding current can be cancelled partially or completely by the flux induced by one or multiple PM pieces. This can lead to increase in the saturation current of the power inductor. Multi-PM distribution schemes are proposed for a power inductor in order to allow for improved and more uniform flux cancellation and therefore higher saturation current. Several PM distribution patterns in the power inductor are evaluated using results obtained from 3D physical models which are developed using ANSYS/Maxwell. The distribution schemes are compared in terms of their effects on the performance metrics of the power inductor. By appropriately selecting or tuning the air gap sizes and the PM dimensions using the 3D physical models in this paper, the multi-PM distribution method can yield higher saturation current with almost no drop in the inductance value.