Model Establishment and Parameter Calculation of Permanent Magnet-Biased Hybrid Magnetic Bearing with Magnet in Rotor

A new kind of permanent magnet-biased hybrid magnetic bearing (MB) with magnet in rotor is developed in order to reduce the bearings volume and magnetic coupling between X and Y degrees-of-freedom. Its principle structure is introduced and magnetic circuit model is established, on the basis of which, the parameters such as maximum force, force to current ratio, force to displacement ratio and the magnetic coupling are calculated. 3-D FEM is adopted to verify the above analysis. The MB has been used successfully in the suspension of an attitude control/energy storage flywheel with angular momentum of 15 Nms at speed of 30,000 rpm, satisfying the demand of good stability and low power loss.