Investigation of the Influence of Full-Pitch and Short-Pitch Windings on Torque and Power Factor of Permanent-Magnet Vernier Machines

Abstract

In this paper, the influence of full-pitch and short-pitch windings on the torque and power factor of permanent-magnet vernier (PMV) machines is studied. It is well known that the short-pitch (SP) winding has shorter end windings but with a lower winding factor. Thus, to achieve the largest torque, the full-pitch (FP) winding is preferred in PMV machines. However, it is found in this study that the SP winding, rather than the FP winding, is a better choice to achieve higher output torque of PMV machine at a high power factor level under the same PM consumption. The advantages of SP winding are even more obvious at higher electric loading and higher power factor levels. The theoretical analysis indicates that torque and power factor are influenced by the winding factor to varying degrees, providing the possibility of better performance of the SP winding than the FP winding. This is further confirmed by the optimization results after performing the multi-objective optimization considering torque, power factor, and PM consumption. Finally, a prototype is manufactured and tested to validate the analysis.