A new permanent magnet synchronous motor vector control system for semi direct drive pumping units is proposed to address the problems of slow response, poor robustness, and insufficient anti-interference ability due to unknown factors in the open-loop control of existing ordinary beam pumping units and permanent magnet semi direct drive pumping units. Firstly, the mathematical model of the system is established,including the natural coordinate system and the transformed coordinate system model. The speed outer loop is set as a new sliding mode surface instead of traditional PI(Proportional-Integral Controller) control to improve the speed tracking performance. Secondly, the current loop predicts the d-axis and q-axis currents at the next moment to reduce errors caused by system dynamic response lag. The sliding mode control, which is insensitive to parameter changes and independent of disturbances, can compensate for the problem of excessive dependence on model accuracy in current prediction control. The constructed outer and inner loop control strategies are integrated and performance expectations are analyzed. Simulation experiments are conductedusing Matlab / Simulink, and double validation is performed on a physical platform. The experiment proves that the new strategy has a good effect on the control of motor speed and torque, improving its robustness andresponse speed.

permanent magnet synchronous motor, sliding mode control, model predictive control, robustness