The Research On Bearingless Disc PM Motor

A new type of bearingless disc PM motor is designed. The rotor is activelycontrolled only in two radial directions and rotation while the other three motions arepassively stable owing to the short-span structure. First, the principle and basic structure of this motor is analysed and the fluxdistribution in the motor is discussed. Then, the minimum pole number is derivedwhich guarantees the control independence of rotation and levitation, also, the radialforce is derived considering the rotor displacement. The theoretical analysis showsthe decouple of rotation and levitation. The mechanical structure and the winding ofthe motor is designed.The linear power amplifier of current-type and the PIDcontroller is designed for the control of radial force.Finally,the outer rotor type discmotor is designed and fabricated in which the rotor displacement is detected by theeddy current sensors. Experimental results show the stable levitation of singlefreedom.