Active Disturbance Rejection Control Method For Steam Generator Water Level Control

The U-Tube Steam Generator(UTSG)is common component of the Pressurized Water Reactor(PWR).Level control systems are used to keep the steam generator water level within the prescribed narrow limits during power demand variations.UTSGs are a class of non-linear,non-minimum phase,parameter changes and uncertain systems.Influent temperatures and other uncertain factors make the control of UTSG a big challenge.Due to the above problem,two types of systems are analyzed in this research(linear and non-linear)for the mathematical modeling of UTSGs of different regions and parameters.One model is linearized and used six variables while the other included all the non-linearites in the mathematical model and used nine variables.In this study there are two main purposes.First one is to model the two systems of the UTSG and study the behavior of these systems by using a MATLAB/SIMULINK tool.Second one is controller design for the water level system of the UTSG non-linear mathematical model.UTSG responses(perturbations such as:feedwater mass flow rate,feedwater inlet temperature and steam pressure)that play a key role in the steam generators safety evaluation.All of these responses are discussed and the results have been carried out.Active disturbance rejection control(ADRC)technique is utilized to solve the water level tracking problem and actively reject the external disturbances during power demand variations.ADRC and the traditional control system(PID controller)have been implemented in a MATLAB/Simulink environment and a comparison study was done.Simulation results show that control method(ADRC)can achieve better tracking performance than PID controller.In addition it has strong robustness in the presence of external disturbances as well as model uncertainty.