Research On Auto Disturbance Rejection Control Of Permanent Magnet Synchronous Motor Servo System

Permanent magnet synchronous motor (PMSM) has become the mainstream of the position servo system because of its advantages such as simple structure, high efficiency, wide application range and stable operation. The double closed loop servo system is often used in the positioning process,but its speed is often out of control.This will not only affect the control accuracy of the servo system, but also bring security risks to the system. In order to solve the problem, this thesis applies three-closed loop control to position servo system. In practical application, the tracking speed and accuracy can not reach higher requirements in traditional servo system.the change of uncertain parameters inside and outside the system will affect the performance of the servo system, which reduces the ability to resist disturbance.This makes the control performance of the servo system greatly restricted. Therefore,it is very important to suppress the unknown disturbances quickly and effectively,and to improve the speed and accuracy of servo system position tracking. Only in this way can we create a high performance servo system.At the beginning of this thesis,the mathematical model of PMSM was discussed,and the vector control of the system was analyzed. Through the simulation analysis of the traditional position servo system controlled by PI,it was found that there was a contradiction between the speed and non overshoot in it. Aiming at this problem, the control method of PMSM based on active disturbance rejection control(ADRC) was adopted.Secondly, the application of ADRC in PMSM double closed-loop speed control system was studied,and the design of speed-loop based on the first order ADRC was completed. Considering the change of the system parameters,the estimation of the model was too large, so the model compensation method was used to optimize the controller. Finally, Control strategy based on model compensation and auto disturbance rejection control effectively reduced the speed response time and tracking error, and improved the system's ability to resist internal and external disturbances compared with PI control.In the end of, the ADRC controller of position loop was added to the speed control system. And then, the PMSM three closed loop servo system was completely constructed. After that, the servo system was simulated in detail. The simulation results shew that the servo system with the new control strategy had faster tracking speed, higher position accuracy and stronger ability to resist disturbance compared with the traditional PI control method. This provided a theoretical basis for the production of advanced high-precision servo system.