Nonlinear Variable Structure Excitation Control Of Power System Based On Lyapunov Theory

With the development of interconnected power network in the world, it requires higher security, reliability and economy of power system, and control has been regarded as an effective measure to improve power system stability. The experts in the country and abroad have made great effort to linear optimal control and nonlinear control, and have gained some significant fruits. Because power system is dynamic large-scale system and has all kinds of incertitude factors, the existed control methods still have the different limits. Therefore, it is importantly theoretic and practical to seek new control theory and method with more excellent performance, especially strong robustness.The design theory and method of variable structure controller have been studied systemically in this paper. The differential geometric control idea has been introduced, and the nonlinear variable structure control rule has been researched comprehensively, and the pole assignment method has been studied. The nonlinear variable structure control of power system based on Lyapunov is advanced, and the results are obtained as following:(1) The variable structure control and the mathematic model of synchronous machine excitation have been studied; The variable structure control switch function has been constructed with pole assignment method of ultimately sliding model; the nonlinear variable structure control of excitation has been designed. The control rule ensure the robustness to the change and the interference of system operating points in theory(2) On the basis of Lyapunov stability theory, the nonlinear variable structure control based on Lyapunov method in the mathematic modeling and application of synchronous machine excitation control has been advanced. The computer simulation indicates: the nonlinear variable structure control based on Lyapunov method has larger sliding model area than the pole assignment method of ultimately sliding model. The nonlinear variable structure excitation control based on Lyapunov method can effectively improve power system stability in transient process( 3 ) Microcomputer Excitation System configuration (frame) has beenimplemented. By building single motor(stand-alone)------infinity system dynamicsimulation system, The dynamic simulation experiments of the general PE) excitation control and of the nonlinear variable structure control based on Lyapunov method have been done. The results indicate: the nonlinear variable structure excitation control based on Lyapunov method can more effectively improve transient response characteristic of power system stability, and they sufficiently incarnate the robustness of operating conditionThe results indicate: the designed variable structure control based on Lyapunov method can effectively improve power system stability; It has high-speed response and nicer dynamic characteristic as well as the pole assignment method of ultimately sliding model; It ensures the sliding model existence and keeps system stability in theory; It fulfils the requirement of control aim and effectively improves the robustness of power system control; It achieves anticipated control effect and has preferable theoretic signification and application foreground.