Analysis of a New Partitioned-Primary Flux-Reversal Hybrid-Excited Linear Motor

A new partitioned-primary flux-reversal hybrid-excited linear motor is proposed and investigated in this article, which features an asymmetrical double-sided primary structure. The novelty of this motor lies in the adoption of a partitioned-primary structure by moving the field excitation winding to an additional primary, thus it benefits from improved space utilization ratio since both armature and field windings can be separately mounted. First, the topology, feasible slot/pole combinations, and operating principles of the proposed machine are introduced. The magnetic flux density distributions in two air-gap regions are comparatively studied from the perspective of magnetic gearing effect. Then, global optimization of the proposed motor with different slot/pole combinations is performed to maximize both the output thrust force and flux-adjusting range based on 2-D finite-element analysis (FEA). In addition, the electromagnetic performance of the motors including flux-adjusting capability, thrust force, detent force, and force ripple with different slot/pole combinations are comparatively investigated. Finally, a 6-slot/7-pole prototype is manufactured and tested to verify the FEA and calculations. It is shown that the proposed motor, benefiting from a partitioned-primary topology, exhibits very good flux-adjusting capability and overloading capacity. Thus, it has good prospect in applications that require flexible speed control.