Research On Permanent Magnet Linear Synchronous Motor Variable Structure Control With Sliding Mode Based On Adaptive Observer

The permanent magnet linear synchronous motor has many advantages in linear driving, so it is widely applied in high-precision linear driving device. The special structure of the linear motor will cause end effect, the perturbation thrust of permanent magnet linear synchronous motor is complex, the control effect of conventional motor control strategy is difficult to achieve the desired effect.This thesis analyzes the mathematical model of permanent magnet linear synchronous motor and its external and internal perturbations from the inner link between linear motor and rotary motor starting,electromagnetic thrust perturbation characteristics caused by the magnetic circuit asymmetry are found. The simulation model of permanent magnet linear synchronous motor is established in the Simulink platform based on a mathematical model, the model provides a reliable and accurate object for the study. There is still electromagnetic thrust fluctuation in the permanent magnet linear synchronous motor vector control, in order to solve the problem, this thesis uses the direct thrust control, and designs speed of sliding mode variable structure controller, and load disturbance feed forward is introduced to Suppress the chattering of sliding mode control. The permanent magnet linear synchronous motor sliding mode variable structure direct thrust control simulation system is established, through the simulation results compare the speed PI regulator and variable structure controller, Sliding mode variable structure controller can effectively restrain disturb-ance of permanent magnet linear synchronous motor.The mathematical model of permanent magnet linear synchronous motor is complex, the traditional observer is no longer applicable to linear motors. The requirements of observer are relatively high in direct thrust control especially in the low stage, the observer based on linear mode is no longer applicable in permanent magnet linear synchronous motor, the thrust flux is equivalent to d-axis flux of ideal model, which simplifies the mathematical model. Based on the simplified mathematical model, the torque formula adaptive observer is designed to solve the formula and thrust observation error caused by the deviation between d-axis and q-axis inductances. Adaptive law of stator resistance is introduced into the adaptive observer, which reduces the error of stator flux observation due to the motor parameter changes at low stage. And the simulation model is established, the effectiveness of thrust flux adaptive observer is verified through the analysis research stator flux and thrust observations.Finally, the thesis design the control system of permanent magnet linear synchronous motor variable structure control with sliding mode based on adaptive observer, and combined with predictive voltage control the system simulation model was established. The steady state and dynamic performance of the control system is simulated and analyzed, and analysis of low speed performance and robustness.