| With the advantages of simple structure, high efficiency, and energy-efficient, the permanent magnet synchronous motor(PMSM) is widely used in the industry. The speed control of PMSM is depended on the detection of the rotor position and speed. Compared with the control method by using mechanical sensor mounted on the rotor axis, sensorless control method is more stable and costless. Under medium and high speed stage the speed and rotor position can be estimated efficiently using the method of detection of back electromotive force or Luenberger observer, but under low speed stage, these methods will lose their effectiveness. So it’s meaningful to research and realize effective speed and position detection algorithm under low speed stage.According to engineering implementation requirements, this thesis researched the speed and position detection problem of the speed-sensorless PMSM under low speed stage. And the solution based on high frequency signal injection method is presented. High frequency signal injection method gets the rotor position and speed information through detecting and processing the high frequency current response by injecting high frequency signal into the motor stator. The implementation procedure and key techniques of high frequency signal injection method is stated. Based on the Matlab/Simulink platform, the code is programed and the PMSM model is connected through the interface of System function(SF). Then the performance of the speed-senorless PMSM control scheme with fluctuating high frequency signal injection is simulated. Also an experimental system scheme based on TMS320F281 x DSP is presented. The software is transplanted. And the static and dynamic performance of the control system is also detected.The simulation results show that the presented fluctuating high frequency signal injection method could detect the rotor position and speed effectively under the whole speed range. The system has good steady-state and dynamic performance. |
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