Topology optimized permanent magnet systems

TL;DR

This paper presents a topology optimization framework for permanent magnet systems, improving magnetic efficiency, field concentration, and field region design through innovative optimization techniques.

Contribution

It introduces a novel topology optimization method for magnetostatics and demonstrates significant improvements in efficiency and field control in three example systems.

Findings

15% increase in magnetic efficiency for Halbach cylinder

111% increase in magnetic field magnitude for concentration device

100% improvement in figure of merit for alternating field regions

Abstract

Topology optimization of permanent magnet systems consisting of permanent magnets, high permeability iron and air is presented. An implementation of topology optimization for magnetostatics is discussed and three examples are considered. First, the Halbach cylinder is topology optimized with iron and an increase of 15% in magnetic efficiency is shown, albeit with an increase of 3.8 pp. in field inhomogeneity - a value compared to the inhomogeneity in a 16 segmented Halbach cylinder. Following this a topology optimized structure to concentrate a homogeneous field is shown to increase the magnitude of the field by 111% for the chosen dimensions. Finally, a permanent magnet with alternating high and low field regions is considered. Here a $\Lambda_\mathrm{cool}$ figure of merit of 0.472 is reached, which is an increase of 100% compared to a previous optimized design.