Optimization and modeling of the homo-polar radial magnetic bearing

To overcome the shortcoming of classical permanent magnetic biased homo-polar radial magnetic bearing (HRMB) about its long axial length, optimization of the structure is done. Then, a precise magnetic circuit model is established by considering its slotting effect, rotor eccentricity and material magnetization characteristic. The flux path in the slot-open region is assumed as quarter-circle, while the flux path in the air gap is the shortest distance between the stator inner surface and rotor surface. The force of rotor is calculated by sum all the force point, which is split even along the rotor surface. The force-displacement and force-current relationships are derived by the magnetic circuit model; the linear mathematics model is built. The 3D finite element method (FEM) results show that the magnetic circuit model can get the distribution of the gap flux density accurately; the linear mathematics model is validated.