Research On Sliding Mode Control System Of Permanent Magnet Synchronous Motor Based On Moment Of Inertia Identification

With the continuous development of highly sophisticated industrial equipment,the requirements for high efficiency motors and their control systems are getting higher and higher.Permanent magnet synchronous motors(PMSM)are used in a large number of applications,such as high-end machine tools,new energy vehicles and industrial robots,because of its structural simplicity,tiny size and superior power density.Nevertheless,PMSM is a strongly coupled and multivariable nonlinear device.When the internal parameters of the motor are regenerated or there are external disturbances,the traditional linear control method is difficult to meet the requirements of high performance control.Therefore,in an effort to improve the control performance of PMSM,this paper is centered on the application of sliding-mode varying structural control in rotational speed control of PMSM and the details of the study are as follows:Firstly,a composite sliding mode control scheme is designed in the speed control of PMSM.A new convergence law is designed and its performance is verified to address the contradiction between the convergence speed and jitter amplitude of the system in the traditional exponential convergence law.Then,the new convergence law is applied to the PMSM speed controller,and a modified sliding mode disturbance observer is proposed to diminish the influence of external load disturbance on the system,and the disturbance is fed forward to the input of the current loop to strengthen the stability of the system.Secondly,to address the impact of the change of rotational inertia of the motor on the control system that has not been considered in the composite sliding mode control,the moment of inertia identification schemes based on the extended sliding mode disturbance observer and model reference adaptive are designed respectively,and an adaptive adjustable gain algorithm is designed to enhance the discrimination performance of the model-referenced adaptive discrimination program,and the identification value is fed back to the composite sliding mode control system in real time.Through simulation verification and analysis,it is concluded that in the compound sliding mode control system of permanent magnet synchronous motor with real-time feedback of moment of inertia,the fluctuation range of speed is smaller,and the system has more stronger anti-disturbance ability.Finally,for the problems that the traditional linear sliding mode surface cannot guarantee the convergence of the system error in finite time theoretically and the singularity in the general terminal sliding mode control,a new fast non-singular terminal sliding mode surface is designed,and the non-singularity property of this surface and the convergence of the system error in finite time are proved by theoretical analysis.Then the second-order superhelix algorithm is introduced to attenuate the jitter of the system,and then the stability of the hybrid second-order sliding-mode speed controller is verified using Lyapunov stability theory,and the effectiveness of this control method is verified by simulation.