The Effect of Magnet Pole Unequal Thickness on Axial Flux Motor Tooth Groove Torque

Abstract

To address the problems of torque ripple, vibration, and noise generated by cogging torque in a dual-stator single-rotor axial magnetic field permanent magnet motor, this article adopts an unequal thickness pole structure to reduce cogging torque. At first, the process of cogging torque generation is analyzed, followed by an examination of the mathematical formulation of cogging torque using the energy technique and Fourier decomposition method. Then, the impacts of several pole optimization approaches on cogging torque reduction are then compared, and the findings are investigated using the finite element method to demonstrate the efficiency of the optimization method. The results show that the optimization effect of unequal thickness pole structure is the best. Lastly, the optimized motor's air-gap flux density, counter-electromotive force, harmonic content, and rotor mechanical strength were compared and studied to demonstrate that the unequal-thickness structure used in this research can increase motor performance. Finally, based on the determined motor parameters, experimental study of the prototype was carried out to verify the correctness of the motor structure and analysis.