Dual-Stator Interior Permanent Magnet Vernier Machine for Torque Density and Power Factor Improvement

An improved topology of a low-speed permanent magnet vernier machine called a dual-stator interior permanent magnet vernier machine (DS-IPMVM) is introduced to significantly increase torque density and power factor. Dual-stator is usually adopted in machine design for more torque and the abundant space utilization. Interior spoke-type magnet array in the rotor is designed for magnet flux focusing, which can effectively increase useful flux and force flux lines pass through the entire machine during operation other than two separate torque components as in a normal dual-stator PM machines. In order to clearly place the advantages of the proposed topology in perspective, the proposed DS-IPMVM is compared to a well-known dual-stator surface-mounted permanent magnet vernier machine (DS-SPMVM). This article discusses the operation principle and magnetic field analysis of the proposed machine and reports the comparison simulation results taken from finite element method. In addition, the stator slot pitch is optimized for further better performance on torque density and power factor.