Research On Speed Sensorless Control Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors are widely used in AC drives,servo motors by virtue of its high efficiency, high torque ands mall size. In the motor control system, optical encoders are usually used to sample the speed. However, the use of mechanical devices will increase the cost of system. So, the speed sensorless control has become one of the hot researches of permanent magnet synchronous motors. By studying the theory of model reference adaptive theory, the thesis designs a speed sensorless precision controller of permanent magnet synchronous motor based on model reference adaptive. Then, researching the study based on the rotor field oriented vector control of PMSM.To begin with, the thesis introduces the control schemes of speed sensorless and the frequency control strategies of PMSM. Analyzing the physical model of PMSM and the mathematical models in three different coordinate systems. The dynamic performance of PI controller is not good enough,so an improved current compensation PI controller is designed to replace the traditional PI controller. By comparing two different regulator’s simulation results, showed that the use of an improved current compensation PI controller can enable the motor system to have a better dynamic performance, fast response, and strong anti-interference ability. So it verified the correctness of the improved method.Secondly, carrying out a detailed study of the permanent magnet synchronous speedless control technology (MRAS), and building a motor control simulation based on this kind of strategy. By comparing with the speed sensor vector control simulation, the results show that under this kind of motor parameter identification method, the rotational speed and torque performance are fine. Verifying the feasibility and advantage of the algorithm. At the same time the accuracy and dynamic response will be influenced by the stator resistance parameter of electric machine to a certain extent.Finally, conducting the experimental study of the motor speed sensorless and speed sensor vector control which is based on the permanent magnet synchronous motor experimental platform. The paper designs the software and hardware for the vector control system of permanent magnet synchronous motor. In order to verify the correctness and reliability of the designed permanent magnet synchronous motor speedless solution, debugging and improving the software and hardware of the controller and comparing the two motor speed control response waveform.