A Study On Dissipative Theory In Robust Nonlinear Control For Power System

Power system is a system with high nonlinearity, in which there exists many different uncertainties. It is necessary to design effective control based on the nonlinear models of power system, and the controlled system has satisfactory properties by considering the existence of uncertainties. This is the problem of robust nonlinear control for power system.A study on dissipative theory in robust nonlinear control for power system is developed in this thesis. Based on dissipative theory, robust control for uncertain nonlinear systems is studied systematically. Combined with the nonlinear model with uncertainty of power system, the methods to realize robust nonlinear control are proposed.The dissertation discusses systematically basic concepts and classification of dissipative system, and outlines the relationship of dissipative system and L2 gain, which establishes foundation to investigate robust nonlinear control problem systematically and profoundly. The problem of robust nonlinear control for a class of single-input single-output nonlinear system with disturbance is considered, and two disturbance attenuation methods in the sense of L2 gain are provided: In method 1, the plant system is divided into two sub-systems, and in the process of recursive method to construct the storage function, the control law which can realize disturbance attenuation with stabilization is derived. In method 2, the coordinates change is considered to make the plant system satisfy the hypotheses of method 1, and then the control law, which can realize disturbance attenuation with stabilization, is derived.Method 1 and method 2 are applied to study the problem of robust nonlinear control for single-machine excitation, and two nonlinear L2 gain disturbance attenuation control laws for single-machine excitation are proposed. The dissertation constructs the normal model for single-machine excitation firstly, introducing the disturbance into controlinput, selecting the state deviation as the state variables, setting a pre-feedback, and then the nonlinear model with disturbance for single-machine excitation is achieved. Method 1 and method 2 are applied to the constructed nonlinear model, and then two nonlinear L2 gain disturbance attenuation control laws for single-machine excitation are derived.Method 1 and method 2 are applied to study the problem of robust nonlinear control for multi-machine excitation, and two decentralized nonlinear Z,2 gain disturbance attenuation control laws for multi-machine excitation are presented. The dissertation constructs the normal model for multi-machine excitation firstly, introducing the disturbance into control input, selecting the state deviation as the state variables, setting the pre-feedback, and then the nonlinear model with disturbance for multi-machine excitation is achieved. Method 1 and method 2 are applied to the constructed nonlinear model, and then two nonlinear L2 gain disturbance attenuation control laws for multi-machine excitation are deduced. All the variables and parameters, which appeared in the control law for generator /, are just measurable locally.Method 1 is used to study the problem of robust nonlinear control for FACTS, and nonlinear L2 gain disturbance attenuation control laws for SVC and TCSC are proposed separately. The adjustable susceptance of the inductor in SVC and the reactance of the capacitor in TCSC are considered as a first order inertial-loop. The dissertation constructs the normal models for SVC and TCSC firstly, introducing the disturbance into control input, selecting the state deviation as the state variables, setting a pre-feedback, and then the nonlinear models with disturbance for SVC and TCSC are achieved. Method 1 is applied to the established nonlinear models, and then nonlinear L2 gain disturbance attenuation control laws for SVC and TCSC are derived separately.To the robust nonlinear control problem for a class of multi-input multi-output nonlinear system with disturbances, a disturbance attenuation method in the sense of L2 gain is presente...