Investigation of Partitioned-Primary Hybrid-Excited Linear Machine with Dual Sets of Permanent Magnet Arrangements

Abstract

A novel partitioned-primary hybrid-excited linear machine with dual sets of permanent magnet arrangements (DP-PPHELM) is proposed in this paper. The proposed topology adopts the design of partitioned-primary, where the armature windings and the slot PMs are arranged in the top primary, while the inset-type PMs are housed in the bottom primary. The excitation fields generated by the dual sets of PMs can be mutually superimposed in the air gap, significantly enhancing the thrust density of the machine. Meanwhile, the field windings integrated into the bottom primary enable flexible regulation of the resultant air gap flux, thereby extending the speed adjustment range of the machine. Firstly, the topology and operating principle are introduced. Then, based on 2D finite-element method (FEM), a global optimization is performed on both the proposed machine and an existing machine for comparison, targeting higher average thrust force, lower thrust ripple, and wider flux regulation range. Finally, the electromagnetic performance of the optimized machines is comparatively analyzed. The results show that the proposed machine maintains comparable thrust density while achieving a 40.27% reduction in PM consumption, along with significantly reduced thrust ripple. © 2026 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.