Research On Robust Control Of Nonlinear Models In Power System

Power system is a multi-dimensional and strong coupling dynamic nonlinear system. In order to guarantee safe and reliable and stable operation of the power system, one of the most effective means is to improve the robust performance of the controller in the power system. In this paper, as a starting point from here, we use the modern control theory and control technology for several typical nonlinear model in power system and consider that the system exists internal parameters uncertainty and is suffered by external disturbance influence in the process of actual operation. Then we establish the robust control model, and design the nonlinear robust controller which is easy to realize.Firstly, we consider that it will be in a state of chaos under special conditions for the PMSM system, and the chaotic system may be influenced by some uncertain factors in the process of actual operation, then we establish the chaos robust control model of PMSM system, and use exact feedback linearization method based on the theory of differential geometry to analyze the robust stabilization and robust output tracking of the system respectively and design the corresponding robust controller, so as to realize the robust stabilization of and robust output tracking of PMSM chaotic system.Secondly, for the single machine infinite power system containing the TCSC device with uncertain parameters, which is affected by the unknown external disturbances, we combine the advantage of the adaptive control method and dynamic surface control method to design the nonlinear adaptive dynamic surface robust controller of TCSC. In the meanwhile, we compare the control effect of the proposed controller with the traditional adaptive backstepping controller through the numerical simulation to highlight the advantages of strong robustness and fast response of the proposed controller.Then, for the simple two-generators interconnected chaotic power system model with uncertain parameters, which is suffered by external periodic load perturbation and electromagnetic disturbance, we combine the backstepping method, adaptive control with sliding mode control to design the dynamic feedback robust controller which makes the closed-loop dynamic error system asymptotically stable. The simulation results show that the proposed adaptive backstepping sliding mode controller has good robustness and the control performance is better than the traditional adaptive backstepping controller and PID controller.Finally, a new kind of adaptive global Terminal sliding mode control method is used to design the nonlinear additive robust controller of HVDC system in AC/DC parallel transmission system with uncertain damping coefficient, which is influenced by uncertain small disturbance with unknown upper bound and three phase short-circuit fault. The dynamic stability characteristics of AC side is improved by rapidly adjusting the transmission power of DC side. The simulation results show that the proposed controller has strong robustness and can improve the dynamic stability of the system effectively. It is also superior to the adaptive backstepping sliding mode controller in the performance of the system dynamic response and estimation of uncertain parameters.