Development and Application of Parallel PM Type Hybrid Magnetic Bearings

Hybrid magnetic bearing is recognized as an efficient one even with wide airgap and suitable for low loss and wide gap application. Previously sub-pole type IPM hybrid magnetic bearing has been proposed. However the sub-pole produces bias flux and cannot produce any control force. To overcome this problem, two new types of hybrid magnetic bearings are proposed which have permanent magnets within their stator cores. This paper introduces structure and principle of the proposed magnetic bearings. The geometric parameters of these new type magnetic bearings are optimized using FEM analysis. The experimental setups are made based on these analytical results. The fundamental characteristics are measured and compared with the estimated bearing performances. The results show stable levitation and good levitated rotation.