Consequent Pole Permanent Magnet Vernier Machine With Asymmetric Air-Gap Field Distribution

In recent years, permanent magnet vernier (PMV) machines have been attracting more and more attention due to the inherently exhibited advantages such as high torque density and simple mechanical structure. In this paper, a consequent pole (CP) PMV machine with single-layer concentrated winding is proposed. The novelty is that the asymmetric air-gap field distribution is introduced to improve its working harmonics and to reduce the PM consumption. By employing a CP structure, the flux density amplitude can be enhanced. Moreover, due to uneven distribution of modulator poles on the armature teeth and fault tolerant teeth, the number of periods of modulator poles is only half of that of the stator teeth. Then, significant improvement in flux density working harmonics can be achieved. Furthermore, the superior electromagnetic decoupling capability can be achieved by introducing the fault-tolerant teeth. The relevant electromagnetic performance such as flux density, back electromotive forces, cogging torque and on-load torque have been calculated by using finite-element analyses, which have also been validated by experiments.