Research On Vector Control Of PMSM Servo System

Servo control system is a mechanical and electrical integration system which putselectrical automatic control in combination with mechanical part. Servo control system hashigh requirements for location precision and dynamic character. At present, semi closed loopcontrol method is used in a lot of servo systems, the controlled object is servo motor. Whilethe precision of the drive chain can not be guaranteed, therefore it will have very importantpractical significance to research high performance AC servo control system. CNC machinetool is taken as the plant of the executing agency, and servo control system of permanentmagnet synchronous motor(PMSM) which directly controls the position of the workbench isstudied in the paper.Firstly， the structure and working principle of PMSM is introduced. And according tothe theory of rotor field oriented, mathematical model of PMSM is established in thedirect-axis and quadrature-axis coordinates. Then voltage space vector PWM which is used inthe VVVF inverter is analysed, and the speed control system of PMSM which is based on thevector control is established. The simulation experiment is taken to verify its good static anddynamic performance under the matlab/simulink environment.Secondly, due to the use of traditional speed sensor, the development of servo controlsystem is restricted in the certain extent. So speed sensorless of permanent magnetsynchronous motor is researched in the paper, and the speed observer of model referenceadaptive based on sliding mode control is put forward. Only by detecting voltage and currentof motor, the angle information of motor can be observed，so that it can instead of speedsensor to gain speed and position of motor. Then the simulation show that the speed observeris feasibility.Because of PMSM is a nonlinear, multivariable, strong coupling control system. when itoperates, parameter changes may generate in the motor. At the same time, the reverse gap,friction characteristic between the workbench and the guide rail may exist in the drivemechanism. High performance control strategies will be applied in the servo position controlinstead of traditional proportional-integral control. So servo system based on activedisturbance rejection controller(ADRC) is present in the paper. ADRC does not depend on theaccurate mathematical model, and the disturbance and error which is product in the run can becompensated timely. This position servo system of PMSM has a better dynamic performance,steady precision and robustness.Finally, under the digital signal processor chip TMS320LF2407A, an implement schemeof servo system is designed preliminarily in the software and hardware and does part of theexperiment based on the above research. The study lays the foundation for further study andapplication.