Parameter Design of Six-Pole Hybrid Magnetic Bearing Considering Variable Stiffness

Six-pole hybrid magnetic bearing (HMB) which driven by an inverter is a kind of high performance bearing with the advantages of small size and low cost. In order to overcome the disadvantage of the six-pole HMB that the working point of the rotor deviating from the given reference point, which affects the stable operation of the six-pole HMB system, the parameter design of the six-pole HMB is carried out in combination with the steady region determined by variable stiffness coefficient. Firstly, the structure and working principle of the six-pole HMB are described, and mathematical model of the radial suspension force in the x direction which considers static working point offset is derived by equivalent magnetic circuit method. Secondly, variable stiffness of the six-pole HMB which considers the static working point offset is analyzed, and the steady region of the stable operation of the six-pole HMB is obtained. Thirdly, combined with the delineated steady region, the parameter design of six-pole HMB is carried out. Finally, simulation and experimental results show that the six-pole HMB system has well performance of anti-interference, which proved that variable stiffness analysis provides a theoretical basis for the parameter design of the six- pole HMB.