Modeling and Analysis of Coupling Performance Between Passive Magnetic Bearing and Hybrid Magnetic Radial Bearing for Magnetically Suspended Flywheel

In this paper, the design and development of a novel magnetic bearing (MB) system which consists of a passive magnetic bearing (PMB) with two pairs of passive permanent magnet rings and hybrid magnetic radial bearing (HMRB) used in magnetic bearing flywheel (MBFW) of control moment gyroscope (CMG) for agile satellite application are presented. The models of PMB and HMRB are proposed and their performances of force-current, force-position, and torque-angle are analyzed using the equivalent magnetic circuit method, finite element method (FEM), and equivalent magnetic charge method. The coupling forces between x and y position degrees of freedom (DOFs) of the HMRB, between the coil current in x-axis and y-axis, between the radial and the axial position DOF of the HMRB, and the coupling force and torque between the translating motion along the x (or y) axis and the rotary motion around x (or y) axis. These coupling problems of the novel MB system are proposed and clarified in this paper. An example is given to clarify the mathematical models and the coupling problems, and the linearized model is proposed for controller design of the MB system.