Research Of Direct Torque Control In Permanent Magnet Synchronous Motor Drives

Firstly, the organization and characteristic of PMSM is introduced, and the thesis presents the recent and new developments of the direct torque control(DTC) techniques for permanent magnet synchronous motors(PMSM),then the mathematics models in various coordinate are set up. And the principle of PMSM DTC is discussed deeply. According to the principle and structure of PMSM DTC. The thesis set up the sub-modules of PMSM DTC system by MatLab/SimuLink.The correction, compensation and improvement methods are investigated in this thesis for the conventional DTC PMSM drive systems according to the problems associated with this method. Specific issues examined are: compensation for the variation of the stator resistance , the estimation of the stator flux linkage, the voltage selection and the problem of the hysteresis regulator.To improve the performance, a space vector modulation(SVM)method is proposed in this thesis to offer the desired space voltage vector for accurate control of the torque and the stator flux linkage. And the thesis presents the recent and new developments of the sensorless method, then a rotor flux linkage vector based speed sensorless method is proposed for the PMSM DTC system in this theses. By the theory analysis and simulation based on MatLab/SimuLink, both the precision of controlling and high dynamic performance was achieved.Based on the simulation, this thesis divided into different logical functions. With the arrangement DSP TMS320LF2407A, the digital control hardware platform is provided. Experiment of TYB300-4 PMSM based on DTC methods are carried out and the experiment results were concordant with those of simulation.