Research On Composite Control Strategy Of PMSM System Based On Improved CSMC Technique

Permanent magnet synchronous motor(PMSM)servo systems have been widely used in important fields of industry.However,PMSM is a nonlinear and time-varying system,it is difficult for conventional linear control methods to satisfy the requirements of high-performance control.The results from domestic and foreign scholars on nonlinear control algorithms show that sliding mode control(SMC)has the advantage of robustness to internal and external disturbances and can meet the requirements of high performance for motor control,but it still has some shortcomings.Therefore,based on the improved continuous SMC(CSMC)technique,this thesis studies the position control problem of PMSM and provides a feasible scheme and theoretical guidance for the realization of high-performance control of PMSM.The main contents of this thesis can be summarized as follows:1.Aiming at the shortcomings of discontinuous control law in conventional SMC methods,a position control strategy based on CSMC is adopted in this thesis.Due to the continuous control behavior of the control method,the chattering phenomenon caused by the high-frequency switching behavior in the conventional SMC can be effectively reduced.The results show that the proposed control method can not only effectively deal with the load disturbance,but also reduce the adverse effect on the control performance of the system due to the existence of the chattering phenomenon.2.Considering the undesirable influences of parameter uncertainties and external time-varying disturbances on the control performance of the system,to further improve the anti-disturbance ability,a composite position control method with feed-forward disturbance compensation and the above-mentioned CSMC technique is proposed.This method introduces the disturbance observer theory into the position servo control system.The extended state observer and the generalized proportional integral observer are designed respectively to estimate the total disturbance of the system;Then the continuous sliding mode position controller and disturbance estimates are combined to form a new composite position control strategy.Compared with the CSMC method,the results show that the proposed composite position control strategy can not only make the system more robust but also reduce the control gain in the CSMC method to make the system obtain smaller steady-state tracking error.3.A PMSM position tracking system is built based on the dual-motor platform.From the perspective of practical application,the feasibility of different control strategies is proved.The experimental results also prove the effectiveness and superiority of the proposed compound position control strategy.