Coordinated Power Regulation Control For Marine Nuclear Power Plant

Nuclear power has been widely used in marine propulsion due to its high energy density and low weight.The dynamics of marine nuclear power plants are strongly non-linear,time-varying and variable coupling.The current PID controller performance is not satisfactory when it is used to control the system during large load change.Therefore,the search for suitable coordinated control methods to improve the load tracking performance of marine nuclear power plant is the main objective of this thesis.The contents of this thesis are as follows:Firstly,a full simulation model of the marine nuclear power plant applicable to the controller design has been constructed.The model has been verified using four typical input perturbations.Then according to the operating characteristics of the nuclear power plant,as well as the physical relationship between the system input and output variables,a control system consists of three single-loop PID controllers,i.e.coolant average temperature control loop,steam generator water level control loop and turbine speed control loop,is designed.The stability of the PID control systems under different operating conditions is also verified using Simulink simulations.Secondly,to compensate for the large lag of nuclear reactor response during the load tracking transient,the steam flow rate,which represents the load of the secondary loop,is introduced as a feed-forward variable to the average coolant temperature control loop,and constitute the nuclear reactor power control system.To solve the time-varying and non-minimum phase problems of the steam generator water level,a scheme of using the measurable disturbance signal as a feed-forward signal and using the internal model principle to design a water level controller is proposed.Simulation results show that the coordinated control scheme based on feedforward compensation reduces overshoot and oscillation,shortens the regulation time and effectively improves the dynamic response of the plant.Finally,to improve the tracking performance and robustness of the marine nuclear power plant further,a coordinated control scheme based on dynamic matrix control is proposed.The scheme uses the PID control loop as the base control layer and the dynamic matrix control algorithm as the upper coordination control layer to optimize input reference signal to the base controller.Simulation experiments show that the coordinated control not only improves the overall load tracking performance,but also has the tracking and robustness of dynamic matrix control,which greatly improves the overall control performance of the power regulation of marine nuclear power plant.