Cogging torque optimization of axial flux motor for flywheel energy storage

Axial flux motors with amorphous alloy stator cores are very suitable for flywheel energy storage systems due to their high efficiency and high power density. The study aims to weaken the cogging torque in yokeless and segmented armature (YASA) axial flux motor with amorphous alloy, exploring efficient optimization measures. First, the theoretical expression for the cogging torque of an amorphous alloy stator yokeless modular axial flux motor was derived. Meanwhile, the three-dimensional finite element model was established to compare and analyze the suppression effects of traditional skew permanent magnets and reverse skew stator shoes, shifted permanent magnets, and reverse skew permanent magnets on cogging torque. Finally, the motor cogging torque is optimized based on the response surface model and multi-objective genetic algorithm(MOGA), and the feasibility of the proposed optimization method is further verified by the finite element method. The results show that by reasonably adopting the three proposed measures for weakening the cogging torque of YASA motor, the cogging torque can be effectively weakened and the no-load back electromotive force harmonic distortion rate of the motor can be improved.