The Research Of Direct Torque Control Of Asynchronous Machine

The Direct Torque Control(DTC) following Vector Control is a new type and highperformance technology. Compared with Vector Control which has complicated coordinatestransformation and strong dependency of rotor parameters, the DTC technique of inductionmotor is known to have fast torque response、a simple control structure and easy to implement.Baesd on the simu1ation of the DTC system with DTC algorithm, the digital software designof the control system is realized with DSP56F8346in the thesis.Firstly，we analyze the AC induction motor dynamic mathematical model as well as thecoordinates transformation and the transformation matrix. And then we explain the basicprinciple and structure of DTC system. Sensor-less speed estimation is an important researchdirection of modern AC Drive, introduction of speed feedback is necessary to get goodperformance of speed regulation. This paper focuses on Model Reference Adaptive System(MRAS) speed estimation based on the rotor magnetic linkage.Secondly, we build every module of the simulation model using Matlab/Simulink whichforms the whole DTC simulation system. We validate the feasibility of DTC methodaccording to the simulation result. Then we simulate and prove the speed sensor-less DTCsystem.Then, we construct the DTC hardware system based on DSP MC56F8346, which iscomposed with two main parts, including the control circuit around DSP MC56F8346, and themain circuit which is composed of IGBT. The main circuit contains non-controllablerectifying circuit and invert circuit composed of IPM. We describe the IPM characteristic andits protection circuit. We also draw the control circuit diagram.Finally, we explain how to construct every module in the DTC system and how toprogram according to the control arithmetic. The system contains main program and interruptservice subprogram, we detailed the interrupt subprogram of PWM Reload and ADC datacollection subprogram, then we draw the program flow chart.In the end of the paper, we summarize the topic and put forward rationalization proposalsas well as ways to improve follow-up study of the subject.