Multi-Objective Optimization Analysis of Auxiliary Flux Modulator Magnetic Gear with Unequal Magnetic Poles

To enhance the output torque and minimize the torque ripple of coaxial magnetic gear (CMG), a novel auxiliary flux modulator CMG with unequal magnetic poles is proposed. This design incorporates an inner rotor with an asymmetric sector and a trapezoidal combined N-S pole structure, featuring Halbach arrays for the arrangement of permanent magnets (PMs). The outer rotor PMs adopt a Spoke-type configuration. To optimize the CMG for high output torque and low torque ripple, a sensitivity analysis is conducted to identify key size parameters that significantly influence the optimization objectives. Based on the sensitivity hierarchy of these parameters, a multi-objective optimization analysis is performed using a genetic algorithm (GA) to determine the optimal structural parameter values of the CMG. In addition, a coaxial magnetic gear (CMG) topology with 4 inner and 17 outer pole pairs is adopted, and the parametric model is established. Finally, the electromagnetic properties of the CMG are evaluated using the finite element method. The results indicate a remarkable reduction in torque ripple, specifically by 46.15%.