Design and Analysis of a Permanent Magnet Vernier Machine with Non-Uniform Tooth Distribution

Abstract

To improve the torque performance of the permanent magnet vernier machine in the direct-drive system for Unmanned Aerial Vehicle (UAV), this paper proposes the topology of non-uniform tooth distribution. This distribution, considering the additional flux harmonics, aims to contribute to torque improvement, whereas the cogging torque also increases at the same time. A phasors method is proposed to solve the issue caused by the non-uniform structure, adjusting the mechanic angle of each tooth reasonably to restrict the cogging torque. In addition, the non-uniform design is illustrated in detail, which includes the method of grouping the teeth, considering the factors of series pole ratio and winding layout. By using the three-dimensional finite element method, torque is significantly increased without additional torque ripple, which satisfies the desired design target.

Design and Analysis of Single Inverter-Fed Brushless Wound Rotor Vernier Machine

“…The hybrid excited PMVM was proposed in order to regulate flux in both directions, which have all of their excitation sources on the stator, thus it helps in regulating the temperature rise of magnets [7]. Axial flux PMVMs to improve power factor, and torque density and minimize the torque ripples by using spoke-type PM, notched-shaped PM and two-stage parallelogram-shaped PM were proposed in [8]. Although PMVMs generate very high torque but the issues associated with these machines are high-cost permanent magnets and their wide-speed operation Vernier reluctance machines (VRMs) are magnet-free machines and hence are less expensive as compared to the PMVMs.…”