A Novel Concentrated-Winding Vernier Pseudo-Direct-Drive Permanent-Magnet Machine

Abstract

The demand for low-speed and high-torque electrical machines is increasing in different applications. Previous research showed that dual-stator magnetically geared machines, such as Vernier pseudo-direct-drive machines (VPDD) can have a high torque density as well as a high power factor. However, the size of their end-winding can affect heavily their torque density. Based on a distributed winding VPDD, we propose a concentrated-winding split-teeth VPDD (ST-VPDD), which can reduce the size of end-winding and output higher torque density. In this research, a model of the end-winding volume is given. Through preliminary design and finite element model FEM analysis, the torque density optimization has been performed to maximize the torque density. Taking the end-winding into account, there is a 93.8% improvement for the torque density, compared to the VPDD, to reach 78.1 Nm/L. After adding a sleeve for mechanical stability, the ST-VPDD still gives a 68.7% improvement compared to the VPDD.