The Research On The Backstepping Control Algorithm Of Permanent Magnet Synchronous Motor Aiming At Against Load Disturbance

Permanent magnet synchronous motor is widely used because of high control precision.However,due to its internal structure nonlinear and strong coupling,external load disturbance and other factors,it is difficult to control exactly.In order to obtain high performance of servo control system,it is necessary to study advanced control algorithms.In the light of the problem that the servo system is seriously affected by the load disturbance,this paper proposes two adaptive backstepping control strategies to make it a better performance.One is combined with model reference adaptive theory,to improve the disturbance compensation of permanent magnet synchronous motor system.The other is to introduce the state observer to the adaptive backstepping control system.Both of them promoted the anti-interference performance of the system.On the basis of constructing the PI control model of the permanent magnet synchronous motor AC servo system.Then the backstepping control algorithm is introduced into the servo system,and we select the deviation of system speed and the quadrature-direct axis current as the virtual control variables of the outer and inner loop.According to Lyapunov stability conditions,the outer loop speed controller is derived firstly,which is the foundation of the whole system stability.In the same way,the current loop controller is derived from outside to inside.Meanwhile,the stability proof of servo system based on backstepping control algorithm is given,and a backstepping control simulation system is built.Finally the feasibility of the backstepping control algorithm is verified.Aiming at the problem of static error in traditional backstepping control,the load estimation adaptive control algorithm and backstepping control are applied to permanent magnet synchronous servo control system.Calculating the load estimate of the system and pass it back to the speed controller.The Lyapunov function is redesigned.According to its stability theory,the adaptive backstepping controllers and load estimation based on load estimation are obtained.Compared with the traditional backstepping control,adaptive backstepping control can ensure there is no error in steady state speed of the control system by estimating the load torque.And it can effectively suppress the influence of load disturbance on the servo system.Aiming at the speed fluctuation of steady state system,when there is a constant change of the system load.The sliding mode observer and adaptive backstepping control are applied to the permanent magnet synchronous servo control system.Firstly,a sliding mode observer is designed based on the mathematical model of PMSM.Based on the Popov's super stability theory,the estimated load is derivated based on sliding mode control and thestable condition.Then adding the load estimation to the speed controller,designing the Lyapunov function,finally the adaptive backstepping controller based on the load estimation is obtained.Compared with the adaptive backstepping control,when the system load torque is disturbed or continuously changed,adaptive backstepping based on sliding mode observer can effectively suppress the impact of load disturbance,ensure steady state speed without error,and make it a better performance of both accuracy and tracking.