Research On Torque Ripple Suppression Strategy Of PMSM Speed Control System

Permanent magnet synchronous motors are widely used in some drive systems due to their small size,simple structure,reliable operation and high efficiency.PMSM speed control system performance is bad due to torque fluctuations caused by changes in the parameters of the motor,external torque disturbances,and other unknown periodic disturbances.Therefore,it is very necessary to study torque ripple of PMSM.In the thesis,the following research on torque ripple of PMSM is carried out:Firstly,aiming at the periodic torque ripple in the control system,a control algorithm combining sliding mode control and iterative learning control is proposed,and a sliding mode iterative learning controller is designed instead of the traditional PI control in the speed loop.The control strategy can solve the problem of poor robustness of iterative learning control through sliding mode control.It is proved by simulation that the torque ripple of the motor can be restrained indirectly by reducing the fluctuation of the speed,and the robustness of the system can be improved,so that the control algorithm is effective.Then,for the problem that the sliding mode control suppresses the failure of the unmatched uncertainty interference,the fuzzy sliding mode control strategy of the nonlinear extended disturbance observer is proposed and extended to the general n-order system.Firstly,the effectiveness of the method is theoretically verified by numerical examples of second-order systems and nth-order systems.Secondly,there is a problem of matched/mismatched uncertainty/ interference for PMSM speed control system.This method is used to suppress the parameter changes and disturbances of PMSM.The simulation proves that the method has strong antiinterference ability when there is matched/mismatched uncertainty/interference in the control system.Finally,the experimental platform of PMSM vector control system is built with DSP as the control center.And the experimental verification of related control method is carried out to illustrate the effectiveness of the control method.The thesis has 46 pictures,7 tables and 52 references.