Analysis and control of radial disturbing force of the axial permanent magnetic bearing in flywheel
                                                                       ZHANG Ruiyu, ZHU Changsheng
                                 (College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China)

Abstract: Aiming at the problem of the radial disturbing force from axial permanent magnetic bearings, the analytical expression was deduced, the amplitude and direction characteristics of the disturbing force were studied and the linearized result was obtained. The relationship between the influence of radial disturbing force and the change of displacement stiffness was concluded. An arithmetic called variableparameter zeroforce control(VPZFC) in active magnetic bearings(AMBs) was investigated to suppress the disturbing force. A simulating model including flywheel system, axial permanent magnetic bearings and the VPZFC was evaluated on the Simulink platform. The results indicate that the disturbing force could be suppressed to 3% of the original with the action of VPZFC in AMBs, which meets the control requirement well.

Key words: axial permanent magnetic bearing； radial disturbing force；equivalent magnetic charge method；displacement stiffness；zeroforce control