Research On Sliding Mode Control For Permanent Magnet Synchronous Motor Based On Model-free Control System

Permanent magnet synchronous motor has been widely used in many industrial productions by its outstanding advantages such as simple structure,no rotor resistance and hysteresis loss,great heat dissipation.But because PMSM is a complex system with multivariable,strong coupling and nonlinearity,and when disturbances occur during operation,it is difficult for traditional control methods to ensure that the system still has good control performance.Therefore,a great number of progressive control strategies have been widely used in this system.In order to improve the performance of PMSM control system,the following related studies are carried out:（1）Two PMSM model-free control strategies based on disturbance observer are proposed.Based on the analysis of the ultra-local model corresponding to the math model of speed loop and current loop for PMSM,a model-free controller based on sliding mode control is designed for PMSM speed and current system.It used a sliding mode observer to estimate and compensate the unmodeled part F of system;Next,a new model-free sliding mode adaptive speed controller and current controller were designed by improving the gain of sliding mode switch.It used the extended state observer to identify the unmodeled part F of system.Finally,after a series of simulation comparisons such as speed increase and decrease experiments,the proposed method can effectively improve the robustness of the system.（2）A model-free current control for PMSM with L₂ robust sliding mode speed adjustment is proposed.Combining the L₂ robust control strategy with the sliding mode control strategy,the L₂ sliding mode speed controller was designed and the SMO was used to identify the load disturbance;Next,the model-free adaptive sliding mode current was designed by adding the adaptive compensation item.These controllers constitute the PMSM model-free current control speed regulation system with L₂ sliding mode speed control.Finally,after a series of simulation comparisons such as speed increase and decrease,the proposed method can effectively improve the system performance.（3）The experiment platform of PMSM was built.The NI controller was the core of the laboratory equipment.It was used to verify the three control strategies proposed above.The experiment results were consistent with the simulation results.It proved the strategies proposed can effectively increase the system performance.The paper has 59 figures,10 tables and 83 references.