Concise magnetic force model for Halbach-type magnet arrays and its application in permanent magnetic guideway optimization

Abstract

In maglev trains, a permanent magnetic guideway (PMG) is an indispensable component that influences their levitation stability. PMG generates the magnetic repulsion force in permanent magnetic levitation and provides the pinning force via coupling with bulk superconductors in superconducting magnetic levitation. Typically, they are arranged in a Halbach array to enhance the magnetic force. However, the spatial inhomogeneous feature of magnetic field makes magnetic force acquisition of the double-sided Halbach array extremely difficult. For accurate magnetic force acquisition, this study proposes a concise analytical magnetic force model and elucidates upon its field behavior. Based on this, a finite element method (FEM) model was developed and verified. The experimental results demonstrated that the Halbach-type PMG’s field distribution was effectively reproduced. Subsequently, the accuracy of the was obtained via comparison with the FEM. The calculation results revealed that the increase in the levitation force tends to be saturated as more magnets are used. For a feasible PMG configuration in terms of high levitation force and low lateral force, the structural parameters were optimized using the multi-objective particle swarm optimization (MOSPO) algorithm combined with the identified magnetic force formulas. The results and findings of this study have significant implications for the design optimization of guideway configurations that heavily rely on permanent magnets.