Design On Speed Sensorless Control System For PMSM Based On Model Reference Adaptive Method

Because of high efficiency and energy density, Permanent magnet synchronous motor (PMSM) has good prospects in various application areas of electric drive field. However, some AC speed control system consist of PMSM do not only have poor robustness, but also highly depend on speed sensors which have reliability and cost problems. For the deficiencies of the speed control system above, the thesis designs a speed sensorless control system for PMSM based on sliding mode control.Firstly, the thesis analyzes the mathematical model of PMSM. It establishes a three-phase static coordinate system of the mathematical model of PMSM. Then according to the theory of space coordinate transformation, the mathematical model and motion equations of PMSM in the two-phase rotating coordinate is given.Secondly, the thesis establishes PMSM vector control system based on sliding mode control. In accordance with the principle of vector control, it implements a control system for PMSM. Then, on the basis of sliding mode control strategy, a new current regulator which replaces the traditional PI regulator is designed. At last, the simulation result of the control system model proves that the speed sensorless vector control system is reliable.Thirdly, the thesis achieves speed sensorless control of PMSM. Based on the vector control system above, in accordance with model reference adaptive method, it uses PMSM actual current model and estimated current model as a reference model and adjustable model, and designs adaptive law for identification of speed to replace the speed sensor. Then it establishes simulation model for designed speed sensorless control system of PMSM based on sliding mode control and analyzes the performance of the whole system. The simulation result of the model shows that the speed adjustment strategy and identification method proposed make vector control system has a good dynamic, static performance and strong robustness for parameter perturbations and uncertainties.Finally, the thesis designs a PMSM automation testing system. The system is used for testing the performance of PMSM drive system in practical application. Compared with the traditional test systems, this system has more advantages, such as saving installation space, cost and energy.