A High Strength and Low Cogging Torque Modulator Structure for Magnetic-Geared Machines

The modulated rotor is usually used as the output component in a magnetic-geared machine to obtain a large output torque, which requires a high-strength design in the rotor structure. In this paper, a high-strength jigsaw modulated rotor is proposed, in which auxiliary slots are also added to suppress the cogging torque. The size, shape, and arrangement of the modulator slots are optimized by finite element analysis. Compared with the conventional low-strength high-output-torque scheme, the cogging torque of proposed design can be reduced by more than 70% while its maximum output torque is only reduced by 3.87%. Compared with the conventional high-strength low-output-torque solution, the cogging torque is reduced by almost 50% on the basis of a 6% increase in the maximum output torque, while the safety factor at the maximum output torque can still be maintained by greater than 2.