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.