The control of the Active Magnetic Bearing(AMB)rotor is a crucial point of the AMB centrifugal compressor for the air-conditioning equipment,in which the main disturbance of AMB rotor in high-speed operation is the unbalance force,it is caused by that there are always be a small radial offset between the rotor center of mass and the axis of rotation of the shaft,the radial offset generates radial disturbance force to the square of the rotating speed.