Vernier Gimballing Magnetically Suspended Spherical Flywheel and Its Rotor Optimization Design

To remedy the limitation of the existing outer rotor scheme which increases the unbalance of rotor system due to screw connection, a vernier gimballing magnetically suspended spherical flywheel with inner rotor based on reluctance force and Lorentz force hybrid configuration is presented. The structure and working principle of the flywheel are introduced, and the control model of rotor system is analyzed. It is concluded that the disturbance of translation suspension on radial tilting control can be eliminated and the controller can be simplified as well when the centroid of rotor coincides with the geometrical symmetrical center of rotor and testing center. In consideration of the maximum equivalent stress, the first-order resonance frequency, the ratio of polar moment of inertia to equinoctial inertial moment, the polar moment of inertia, the maximum deformation and the deviation of the centroid of rotor and the sphere center of rotor are increased as constraint condition. The multidisciplinary optimization design of rotor system is performed by taking the high sensitivity parameters as optimal design variables and the minimum rotor mass as the optimization objective. The results indicate that the mass of rotor is decreased from 5.600 kg to 5.389 kg, which is reduced by 3.8%, under the condition satisfying the design requirements. The optimization design method can improve the design efficiency and control torque precision of flywheel system.