Research On Permanent Magnet Synchronous Motor Servo Control System

With the constant promotion of industrialization, Servo system is playing an increasingly important role in industrial production. Meanwhile, Permanent magnetic synchronous motor has been widely used in servo systems of medium and small capacity due to its advantages of high power density, simple structure and high efficiency. Research of digital ac permanent magnet servo system has became a hotpot in the field of electric driving. This paper studies and designs the servo system and related control scheme of PMSM, which has practical significance for industrial application.Firstly, PMSM was analyzed mathematically, models under different coordinate system were presented. According to the coordinate transformation theory, vector control method was introduced. This paper also provided several current control strategies, and chose id=0 plan for the control system. At the same time, SVPWM method was studied to improve the use of DC supply voltage.Based on the TMS320F28335 DSP, this paper built a control system including both hardware and software design. Hardware system includes main circuit, power circuit, sampling circuit, and so on. Software design covers the main program and interrupt subprograms. In order to avoid the influence of dead time, related compensation method was studied.Control strategies of current loop and speed loop was taken into research. To improve dynamitic performance, this paper chooses current predictive control method for the current loop control. However, traditional current predictive control method would have current disturbance due to parameter mismatch and model uncertainty. Then a new current predictive control method based on extended state observer was proposed to reduce the disturbance. Extended state observer observed DQ currents to amend reference currents. At the same time, both internal and external disturbance was estimated, which was used to compensate reference voltages. Speed controller combined PID with fuzzy theory, which considered motor speed and its derivative as inputs. With the help of fuzzy inferential decision, PID parameters can be adjusted by controller itself. For restraining windup phenomenon, reversing calculation strategy was used in the speed controller. At last, experiments were taken to prove the effectiveness of the algorithm proposed.