The Driver Design And Control Algorithm Research Of PMSM Servo System

Along with the development of motors’ manufacturing process, power electronic technology and modern control theory, servo system using PMSM as actuator has been applied widely. The stability of servo system at low speed is one of the key factors influencing the application of servo system. This paper revolves around this problem. Firstly, the development of the related technology of servo system and the general situation of the research in low-speed field is introduced. Then, the structure and operating principles of PMSM is analyzed. Furthermore, the mathematical models of PMSM in various coordinates are deduced combined of coordinate transformation. Finally, the servo system is designed and realized to study the control algorithm.Syntron’s 60CB020 C motor is chosen as the controlled object, and the controller module is designed based on TI’s TMS320F28335, while the power module is designed based on IR’s IRAMS06UP60 B. The software of the rotor flux field-oriented vector control(FOC) contains main module, FOC interrupt service module, protection interrupt module and eQEP interrupt module.Two shortcomings of the hardware design and control algorithm are improved. In order to improve the low speed performance, the paper proposes two strategies. In the method of speed measurement, an M/T mixed method is designed to adjust the error in the switch of low speed and mid-high speed. The dead-time problem in the SVPWM control is researched and a compensation strategy is proposed. The result of the experiment shows that the steady-state error is reduced effectively.The disturbance of friction and load torque always exists in the servo system, especially in the low speed system. Friction’s effect and model is introduced in this paper, and a sliding mode control algorithm with both friction observer and load disturbance observer is proposed to eliminate the effect of the nonlinear disturbance. The simulation and experimental results show that this method can compensate the torque and improve the tracking precision and the performance of anti-jamming of the low-speed servo system effectively.