Axial force tilting permanent-magnet-biased magnetic bearing with five degrees of freedom and magnetic field decoupling design

To satisfy the requirement of the tilting moment ability and precision of magnetically suspended flywheel on spacecraft, a novel permanent-magnet-biased magnetic bearing with five degrees of freedom (5-DOF-PMB) was presented, which applied axial force to control rotor tilting motion to obtain high stability with improved intrinsic modal of rotor, and was also beneficial for increasing system-integrated-level. It was verified by finite element analysis (FEA) simulating that 5-DOF-PMB designed based on the 15 N·m·s reaction flywheel could support full loads on all degrees of freedom simultaneously. To satisfy the requirement of high control precision of rotor vibration on large excursion, magnetic field decoupling design for 5-DOF-PMB was accomplished. It was verified by equivalent-magnetic-circuit method and FEA simulating that the magnetic field coupling between two radial channels was weakened in two orders after decoupling design for 5-DOF-PMB. Further, a universal method to decouple magnetic field of PMB was generalized.