Research And Analysis Of Direct Torque Control System Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor (PMSM) has many excellent performances, such as small volume and high efficiency. People has paid more and more attention to it. Since Direct Torque Control of asynchronous motor has been realized, Direct Torque Control is well known by its simple structure and quickly dynamic response and has been rapidly developed in recent years. In the field of AC speed regulation using asynchronous motors, DTC has the perfect performance. But it is immature in the appliance of PMSM and need further research. Based on the analysis of the methods of DTC in existence this thesis gives a scheme of PMSM DTC and do some simulations and experiments. The main contents of study are as follows:An introduction of space vector is presented firstly. The mathematics model of PMSM is established as follows. Then, the equations of PMSM in the circumrotate coordinate of stator and rotator are deduced.Based on the running characteristic of air-conditioning compressor, the simulation model of PMSM DTC is set up in using MATLAB/Simulink.According to the analysis of the theory of PMSM DTC scheme, the thesis designs the hardware system and software system based on the DSP.Because the traditional DTC has some disadvantages, the thesis gives the strategy of PMSM DTC based on space vector modulation. The result of simulation shows that SVM-DTC has better performance than traditional DTC. At the last, the thesis discusses the method of sensorless DTC. Estimation of rotator speed based on the parameter of stator is proposed in this paper.