Abstract: An approximate non-minimum phase transfer function of magnetic suspension bearing is established, on the basis of that, a closed-loop controller is designed and makes the whole system stable. The parameter of the controller is turned with the method of simulation. This paper analyses changing curves of rotor displacement under the situation of different disturbance and changing curve of electromagnetic force and reason of high-speed rotor out of control, meanwhile, discusses the relationship among the parameter of controller and stiffness of electromagnetic bearing and rotor stability.

Key words: Bearing, Closed-loop control, Magnetic suspension