A Mathematical Model and Control Analysis of Magnetic Bearings

Magnetic bearing is a new non-contact bearing supported by electric force, and it has some advantages in comparison with conventional bearings. The basic principle and structure of magnetic bearings are introduced in this paper. On the basis of a mathematical model with one degree of freedomfor a couple of fixed radial magnets, a PID controller for the systemwith innate instability is discussed, and the effects of the controller parameters on system stability are analyzed. In addition, main problems to be solved for the magnetic bearing applied in high-speed rotation machinery are also presented.