A Novel Permanent Magnet Vernier Machine With Halbach Array Magnets in Stator Slot Opening

Permanent-magnet vernier (PMV) machines are attracting more and more attention due to their high torque density and simple mechanical structure. In this paper, a novel PMV machine with an improved permanent-magnet circuit is proposed. Compared with the regular PMV machine, half of the permanent magnets (PMs) in the rotor are moved to the stator slot opening, and Halbach array PMs are employed in the stator while the consequent pole is employed in the rotor. The analysis of this machine indicates that the back electromotive-force amplitude of the proposed PMV machine could be two times that of the regular PMV machine with similar magnet usage, and for the same torque density, viz., 23.1 kNm/m3, the power factor of the proposed machine can reach 0.89, while this value is only 0.65 in the regular PMV machine.