Study Of Robust Speed Control System For AC Asynchronous Motor

Due to multivariable, nonlinearity, strong coupling and varying with temperature changes of the parameters of asynchronous motor, it is difficult to find control methods with expected permance. How to improve the robustness of the system to achieve efficient control has important theoretical and practical significance.On the basis of the research on AC variable speed control strategy, firstly, the paper establish a mathematical model of the asynchronous motor, Then introduces the basic principles of robust control. Then, contrary to the induction motor is difficult to directly measure the rotor flux, the paper give a method for application of Linear Parameter Varying Theory to design flux observer. Take asynchronous motor as the LPV system, and the variable parameters of the system are rotor speed and stator resistance. Then, utilize polytope technology to design flux observer. The method greatly reduces the amount of computation, the observer has greatly improved in the interference suppression and dynamic characteristics. The simulation results show the effectiveness of the method.Contrary to the model of asynchronous motor with nonlinear coupling, the paper give a control method for application of robust control system to design controller. Firstly, make the amplitude of the rotor flux and the rotor angular velocity completely linear decoupling, and then design the disturbance reject adjuster by the robust control theory, design the servo optimum adjuster by optimal control theory. The method solves the problem of nonlinear coupling of vector control, and the algorithm is simple and easy to understand. Computer simulation results show that the system has a good dynamic and static performance.