Design And Implementation Of PMSM Controller Based On Speed Estimation

In recent years, the developing mode of the electric vehicle(EV) is transforming from the cheap low-quality to cost-effective and high-quality. Many EV manufacturers have used permanent magnet synchronous motor(PMSM) as the power source of EV. Its flexibility of structural design and excellent performance makes it very suitable for an EV’s powertrain. The traditional movement control system gets motor speed and position information as feedback signals of the closed-loop system through the photoelectric encoder or tachogenerator which not only increased the cost, but also not conducive to the lightweight of the products at the same time reduced the reliability of the system. In order to solve this problem, researchers put forward the sensorless control method for PMSM, which estimates the rotor speed and position through the other parameters which is easy to measure in the PMSM model to realize the movement control of the PMSM.This subject studied the PMSM controller based on speed estimation adopting the method based on double observer. A PMSM controller based on the low speed EV was designed. And the control algorithm was realized on the controller experiment platform. The controller obtained the good control performance. The main work is as follows:Firstly, a lot of literatures within the territory were read to understand the research status of PMSM control method. The theoretical foundation and realization method of the different control method were analyzed. The significance and the method of sensorless control of PMSM were discussed. The advantages and disadvantages of current different PMSM controller implementation scheme were compared. The theoretical basis and overall thought of controller realization were summarized.Secondly, the mathematical model of PMSM through reading literature was established. The principle of coordinate transformation was available. The vector control of PMSM based on the coordinate transformation was studied. The structure and principle of PMSM controller on the background of EV were introduced.Thirdly, this paper put forward a sensorless PMSM speed control method based on double observer which used the sliding mode observer to estimate current and the back electromotive force observer to realize the estimate of the speed. This method improved the speed and precision of the speed estimation. The stability of double observer was proved with Lyapunov stability theory. The algorithm was simulated with Matlab.Fourthly, the different realization methods of the controller through reading a lot of technical documents related to the PMSM and the evaluation system were understood. According to the advantages and disadvantages of various methods, the implementation scheme of PMSM controller based on speed estimation was determined. The controller hardware was designed according to the plan. The debugging of the controller was completed, and the control method based on double observer was implemented on this basis.Finally, experiments have been carried out on the experimental platform of controller to test the performance indexes. The experimental results show that the combination of the designed controller and the control algorithm can achieve fast smooth speed tracking performance. And the shortcomings existing in the system were analyzed. Some methods to solve these deficiencies were proposed.