Amelioration of Coreless Permanent-Magnet Disk Synchronous Motor Based on FEM: Motor With Wedge Airgap Original Research Article

A novel coreless PM (permanent magnets) disk synchronous motor, consisting of a single stator in the middle and twin rotors on both sides, is proposed in this paper. NdFeB magnets with high coercivity and high remanence are used, and a special arrangement of PM—Halbach array is employed to enhance the magnetic flux density in the airgap. Cylindrical PM array is stuck on the rotor to avoid the eddy current wastage, which is caused by reciprocal movement between the rotor and the PM array. The stator contains a winding molded by high mechanical integrity plastic without any core. Besides, the wedge airgap is designed to reduce the equivalent length of the airgap, and hence to advance the performance of the motor. The analysis of the magnetic field has been done by FEM method. An example motor of the design in this paper has been made, the magnetic flux density of which reaches 0.53 T, and the efficiency of the motor is above 92%. The motor has a better performance in each phase, and the aim of amelioration is achieved.