Research On Speed Sensorless Vector Control Of Asynchronous Motor Based On MRAS

In many years,people have made lots of researches in the field of high-performance electric drive of asynchronous motor ,which make the equivalent conversion from AC motor module to DC motor module to control its speed and torque using the coordinate transformation theory based on the excellent speed performance of DC motor, and finally attain very proud results. Recently, people work on speed sensorless vector control system with high-performance effect without speed sensor. Because of its many advantages in one set, it strongly attracts people's attention. It is in this context that this article starts the research on speed sensorless vector control based on MRAS.First, This paper reviews the development history of AC electric drive system, and analyze the cause that AC electric drive is bound to replace the DC electric drive, and introduce the strong development drive of AC electric drive system-power electronic and microprocessor technology.Second, this paper introduces the basic theory of coordinate transformation, and analyze asynchronous motor's dynamic mathematical model in different coordinates. Then we obtain vector control basic equation under the oriented rotor field.Third, this paper details the model reference adaptive speed identification algorithm based on the scheme of rotor flux,back electromotive force,instantaneous reactive power. Model reference adaptive theory is an parameter identification scheme based on the stability design. The accuracy of the reference model directly determines the effectiveness of the system parameter identification. After comparison between the three speed identification schemes, finally, The speed identification scheme based on instantaneous reactive power model reference adaptive algorithm is selected. Then the speed sensorless vector control system simulation model is built using MATLAB / Simulink software. It is proved that the program has a good effect on the speed recognition, and shows its good dynamic and static performance in the same time.In the end, this paper designs the speed sensorless vector control system based on TMS320F2808 DSP. The hardware of the system is designed, mainly containing the main circuit and control circuit. The main circuit includes the rectifier circuit,filter circuit,drive circuit and the pumping voltage limit circuit. And the control circuit includes the PWM generation circuit based on DSP2808. The software of the system is designed, including main program,interrupt service routine and fault interrupt handler procedure.