Sensorless Control Of Permanen Magnet Synchronous Motor Based On Sliding Mode Variable Structure

Permanent magnet synchronous motors(PMSM)are widely used in many fields due to their excellent characteristics.Traditional PI control methods cannot meet the complex requirements,and in order to improve the control effect,accurate rotor speed and position information needs to be obtained.This paper investigates control methods and position sensor-free control techniques for PMSM high-performance speed control systems to solve the problems of insufficient robustness,weak anti-interference capability,slow response and jitter in traditional methods.The details include:(1)The mathematical model of PMSM is established through coordinate transformation.Then,vector control and voltage space vector pulse width modulation techniques were used to construct the PMSM vector control system model,and its effectiveness was verified by simulation.(2)To solve the problems of the conventional sliding mode controller(SMC),this paper designs a model-free non-singular terminal based sliding mode controller(MFNTSMC),which eliminates jitter in the control process by introducing non-singular terminal terms and uses model-free control to eliminate the dependence on the model,thus making the controller more adaptive and robust.An Extended Sliding Mode Disturbance Observer(ESMDO)is introduced for load abrupt changes for estimation and feedback.Simulation results show that the improved sliding mode speed controller is more responsive and significantly more robust compared to SMC.(3)To solve the problems of the conventional sliding mode observer(SMO)in positionless sensors,this paper designs an adaptive superhelix-based sliding mode observer(ASTSMO),which can better adapt to non-linear systems and perturbed environments by introducing adaptive and superhelix functions to design the sliding mode surface,thus achieving more accurate and robust state estimation.To better control the robustness and accuracy of the observer,a normalised phase-locked loop is introduced to achieve accurate tracking,thereby improving the accuracy of the controller and suppressing jitter.Simulation results show that the improved sliding mode observer is more responsive and robust compared to SMO.(4)In this paper a PMSM hybrid sliding mode control system is constructed.By using an improved sliding mode speed controller and observer,a new speed outer loop is formed in combination with the hybrid sliding mode system.Simulation results are compared with the conventional hybrid sliding mode system and confirm the effectiveness of the improved strategy proposed in this paper.