Anti-windup Multivariable Sliding Mode Control With Disturbance Observer

With the development of control technology and power electronics technology in the field of the servo control,the AC servo control technology is widely used in daily life and industrial production,such as the air conditioner in the home appliances,the machine tools and robots in the industrial production,etc.However,there are many different types of disturbances in the practical servo control system,which will degrade dynamic and static performance of servo control system,such as the parameter perturbations of the control system,the measuring error of feedback,the change of load and other uncertainty external disturbance,etc.So,the research on multivariable robust sliding mode control strategy with disturbance observer compensation is very important in theory and practical.For the current loop control of permanent magnet synchronous motor speed servo system,the paper proposes an anti-windup multivariable sliding mode control with disturbance observer,to optimize the current loop control,to enhance the robustness of current loop,to improve the tracking performance of current loop control system,and to achieve a good speed servo performance.The designing of the control method mainly includes the following parts.First of all,for the current loop of permanent magnet synchronous motor,based on the general structure of the disturbance observer and the thought of the internal model control,the article proposes a new type of disturbance observer which is the current loop observer based on internal model control.On the basis of the model control theory,The observer build a internal model equations for the current loop,introduce an augmented matrix with the error between the actual current and the internal model current,and design the observer control law with the state feedback and the pole configuration optimization method,which ensures the steady-state performance of the observer.Secondly,considering the strong robustness of sliding mode variable structure control,the article designs a new type of sliding mode control strategy,which is the multivariable sliding mode control with the second-order nonsingular terminal sliding mode.The control method is not only designing simply and realizing easily,but also avoid the shaking caused by the discontinuity of switching function in conventional sliding mode control.There is no switching function,but the integral of switching function in control law,and the anti-windup method is used for the integral.Therefore,the control method not only retains the robustness of sliding mode control,but also reduces the shaking of sliding mode control.Finally,the proposed compound control method is used to the current control of permanent magnet synchronous motor speed servo system.Firstly,based on the vector control technology,the equivalent dc motor model of permanent magnet synchronous motor is obtained by the coordinate change,the MATLAB simulation model is structured,and the composite control scheme is designed,then the research and analysis the performance of the control system is made,the rationality of the algorithm is validated in theory.Secondly,the control program is made in the permanent magnet synchronous motor control experiment platform,the core of which is TMS320F8212DSP,to verify the effect of experiment and to make comparative analysis.The simulations and experiments indicate that the proposed control method enhance the robustness of the system,reduces the current fluctuations,improve the steady state accuracy of the current with the result in a better performance of speed regulation for permanent magnet synchronous motor.