Sliding Mode Control Of Uncertain Nonlinear System And Application For Permanent Magnet Synchronous Motor

In recent years,the control problem of uncertain nonlinear systems has been paid much attention by scholars both at home and abroad.Now it has become an important branch of modern control.Sliding mode control has been applied in various fields of industry because of its strong robustness to external interference and uncertainty caused by parameters.In this paper,the sliding mode control of uncertain nonlinear systems is studied,and is applied to the control of permanent magnet synchronous motor systems.The main contents and innovations are as follows:Firstly,the sliding mode control for the nonlinear system with matched and unmatched uncertainties is studied.So as to achieve the convergence of estimation error in finite time,the uncertainty of the system is estimated by the disturbance observer.A sliding mode control based on integral sliding surface and multiple power reaching law is designed to avoid chattering problem of traditional sliding mode.Compared with the sliding mode control based on single power and double power reaching law,the sliding mode control designed improves the convergence speed of the system.Secondly,the adaptive finite time control of semi-strict nonlinear systems with matched,unmatched uncertainties and unknown parameters is further studied.The unknown parameters in the sliding mode control system are estimated by the adaptive law,and the comprehensive interference is estimated by designed disturbance observer.A sliding mode control based on multiple sliding surface is proposed to avoid chattering.The numerical simulation is conducted to prove effectiveness of the developed control strategy.Finally,the sliding mode control method is applied to the permanent magnet synchronous motor speed control system.The dynamic sliding mode surface and control strategy are designed,which effectively reduces chattering and improves the control accuracy of the permanent magnet synchronous motor system.The system has strong robust.In this chapter,two different sliding mode control strategies are proposed,and the controller of the permanent magnet synchronous motor is designed.The stability of the permanent magnet synchronous motor system is proved by using the Lyapunov stability theory.The simulation results show that the control strategy can realize the fast tracking of the angular velocity of the motor and avoid the chattering.