Direct Torque Control System Using Space Vector Modulation For Bearingless Permanent Magnet Synchronous Motor

A bearingless permanent magnet synchronous motor(BPMSM) is a high performance PMSM adopting bearingless technology, In the stator slots, the BPMSM has a set of additional suspension force windings except motor's torque windings. The rotor shaft can be successfully suspended and the BPMSM can operate under high speed or hypervelocity. Therefore, the bearingless motors have functions and virtues of magnetic bearings and permanent magnet synchronous motors, And has potential prospects for applications in the hi-tech fields of chemistry & chemical engineering, life sciences, energy transportation, aerospace, robot, etc. The theory and experiment research around operational mechnism, mathematical model, control methods and the digital control systems of the BPMSM has carried out in the dissertation. The main work is as follows.Firstly, the mathematical model of BPMSM is established according to Maxwell tensor method, after the analyzing the working principle of BPMSM.Secondly, based on the principle of producing radial force and the mathematics model, the space vector modulation direct torque control system is introduced to the decoupling control system of BPMSM. The stator voltage and current are detected adopting Extended Kalman Filter(EKF) to estimate rotor's speed and position, therefore, the speed-sensorless operation of the control strategy is realized. EKF models of BPMSM in Matlab/Simulink simulation environment are constructed and the simulation study is carried out. The simulation results show that EKF can estimate the state variables accurately, ideal speed tracking performance, satisfactory robustness and the good performance of the radial levitation can be achieved by using the proposed method.Finally, based on the principle of producing suspension forces and the mathematics model and using DSP TMS320F2812, the hardware and software of the digital control system have been designed and developed in the dissertation. The digital control system of BPMSM has been debugged and the relative experimental results have been analyzed for 2 degrees of freedom BPMSM. Through the part experiments and testing, the hardware and software have been optimized. The experiment results have shown that the theory is validity for the BPMSM.