Accurate Subdomain Model for Computing Magnetic Field of Short Moving-Magnet Linear Motor With Halbach Array

Abstract

This article presents an accurate analytical model to compute the magnetic field in a short moving-magnet linear motor with any pole and slot combinations. Two kinds of end effects caused by the finite length of the stator and mover are considered. The stator end effect is addressed by an equivalent slotting subdomain based on the subdomain analytical method. The mover end effect is analyzed with a virtual mover consisting of the mover and two additional virtual units. The length of virtual unit is given according to the effective motion stroke and magnetic circuit, and the remanence of permanent magnets in virtual units is specified as zero. A linear motor with 8 poles/6 slots and a Halbach array is used to verify the correctness of the proposed analytical model. Compared with the results from the finite-element analysis and previous subdomain analytical model, the proposed analytical model shows high accuracy on the calculations of the magnetic flux density, cogging force, and normal magnetic force.