Basic Technology On Bearingless Permanent Magnet Slice Motors

The bearingless peamanent magnet slice motor, which combines function of synchronous motor and magnetic bearings, can provide both torque and radial suspension forces. The rotor of the bearingless peamanent magnet slice motor can rotate with no mechanical friction. In recent years, bearingless peamanent magnet slice motors have been developed for semiconductor industry, chemical industry and life sciences field. This dissertation focuses on the fundamental theory and experiments of bearingless peamanent magnet slice motor including driver system models, the digital control system design and transducer. The detail contents are as follows:Firstly, the principle of radial suspension force is expounded. The drive system model of the bearingless peamanent magnet slice motor are deduced. In order to realize the control of torque and radial suspension forces for bearingless peamanent magnet slice motor, a control system based on rotor flux oriented control is designed. The structure of slice motor is studied and the correctness of suspension principle are verified by ANSOFT software, which is finite element analysis software of electrical machines.Secondly, the principle of a three-level voltage convertor is studied and expounded. Using Matlab/Simulink toolbox, the simulation model is established and the capability of the three-level voltage convertor is verified. Based on the capability of a bearingless peamanent magnet slice motor,a CRPWM convertor and signal interface cards are designed and realized.Finally, based on the principle of rotor flux oriented control, the hardware digital control system is designed and set up ,and the flowcharts of each software functional block are presented. The digital control system is debugged and optimized. The experimental rig of digital control system is set up and is used to validate the control system, the CRPWM convertor and the signal interface cards.