Research On Outer-Rotor Bearingless Induction Motor And Its Control System

As bearingless induction motor(BIM) combines the maglev technology with traditional asynchronous motor, it not only has the advantages of no friction, no abrasion, high axial space utilization rate, high rotor critical speed, but also has the advantages of traditional of asynchronous motor simple and high reliability, uniform air gap, low cost. So BIM has become one of the research hot spots in the field of motor bearing.On the basis of the completion of the National Natural Science Foundation Project which is adaptive inverse decoupling control and digital technology of high speed magnetic levitation motorized spindle for CNC machine tools(61174055) and other projects, the mechanical structure, operation mechanism, electromagnetic analysis, operation control and digital system of the BIM are studied. The design of two degrees of freedom BIM and optimization of its the main structure and electromagnetic parameters are finished. Based on digital signal processor TMS320F2812, the digital control system of asynchronous motor is designed, and the related simulation and experimental research are carried out. The specific contents are as follows.Firstly, by analyzing the principles of radial suspension force and magnetic torque, mathematical models of radial suspension forces are deduced by Maxwell stress tensor method, and then the voltage equation, flux equation, torque equation and motion equation are analyzed.Secondly, this dissertation designs the bearingless outer rotor induction motor,and studies the effects of motor parameters on the motor performance. On this basis,the prototype model is analyzed and optimized by finite element analysis software.Finally, the digital control system of bearingless outer rotor induction motor is built up by TMS320F2812. The hardware drive circuit and the modular software programs are designed. Considering the design prototype motor as the researching object, the experimental study is carried out on two degrees of freedom. The experiment results show that the theoty is validity and this control system lays somefoundations for further research on how to realize the bearingless motor suspension with the five degrees.