Radial position control of a PM synchronous type and induction type rotating motor

In this paper, a general solution of a radial position control applicable to a PM synchronous type and induction type rotating motor is presented. The rotor of the permanent magnet motor is assumed to have the sinusoidally distributed magnetic poles along the axial surface, while the rotor of the induction type motor is assumed to have the uniform magnetic property. The inner wall of the stator is also assumed to have a current sheet, which can produce an arbitrary current distribution. The same number of magnetic pole gives the rotating torque to the rotor, while the plus minus two pole of the motoring control produces a pure drag force to the rotor. By controlling the magnitude and phase of the plus minus two pole current distribution relative to the motoring magnetic pole, the drag force can be controlled in the radial coordinate. This general solution is experimentally confirmed by using a simple experimental setup