An integrated toroidal winding design for open-winding magnetless vernier reluctance linear machine in long-stroke module

Abstract

Vernier reluctance linear machines (VRLM), taking advantage of controllable magnetic field, simple structure, and low consumption of rare-earth material, are promising actuators for long stroke applications in industrial processing field. However, due to the limited excitation, this machine exhibits limited force density with redundant field winding, which hinders its wider application. Aiming to eliminate dc coils, simplify manufacturing process, and strengthen its load capacity, an integrated toroidal winding design excited by zero-sequence current is proposed for VRLM in this article. The key is to compare different arrangements of excitations to boost the contents of working harmonics, make better use of modulated harmonics, and select a proper gear ratio. Driven by integrated toroidal winding, the slot utilization of VRLM is improved, and the manufacturing process of the machine is significantly simplified. In this article, winding arrangements of VRLM and its working mechanism are analyzed, along with some design guidelines, including slot-pole combinations, geometric dimensions, etc. Finally, the prototype is built for performance evaluation and experimental verification.