Research On Modeling And Control Methods Of Single-reactor And Double-turbine Nuclear Power Plant

Nuclear-powered ships have the advantages of high power,strong endurance and stable operation characteristics.The research and development of large marine nuclear power system is of great strategic significance to our national defense and national economic development.However,at present,there is still little research on modeling and dynamic characteristics of large marine nuclear power plants.For the control system,the research mainly focuses on the local control and the simple coordination based on the traditional PID controller.Therefore,the author takes the single-reactor and double-turbine nuclear power system in the large marine nuclear power plant as the research object in this paper.Research work is carried out on modeling simulation,characteristic simulation and control system design based on advanced control algorithm.In this paper,based on the laws of conservation of mass,conservation of energy and conservation of momentum,the lumped parameter method is used to establish the mechanism model of the PWR reactor core,pressurizer,steam generator and saturated steam turbine of the single-reactor and double-turbine nuclear power plant.The parameters that cannot be determined in the mechanism model are obtained from the existing large-scale nuclear power ship simulator.Based on the MATLAB/Simulink platform,the mechanism model construction,parameter debugging and model rationality verification of the single-reactor and double-turbine nuclear power plant are completed.Then,the dynamic characteristics of each equipment and the whole system of the the single-reactor and double-turbine nuclear power plant are analyzed by step disturbance simulation experiments.The results show that the whole system model is stable and the thermal inertia time of each equipment is reasonable.Based on the analysis of the characteristics of the three local control loops: reactor power control,pressurizer pressure and water level control,and steam generator water level control,the corresponding control strategies are put forward in this paper.And the designed controllers have good performance.(1)The eclectic control scheme for the average temperature drift of the primary loop is selected.And the reactor power controller is designed based on the traditional PID algorithm.(2)According to the characteristics of multi-parameter coupling and large inertia of the pressurizer,the multi-variable MPC algorithm is used to design the pressure and water level controller of the pressurizer of the marine nuclear power plant.(3)Aiming at the nonlinear characteristics of steam generator and the phenomenon of "false water level",considering the influence of main steam flow fluctuation on water level,a feedforward predictive control algorithm is used to design a steam generator water level controller.In order to solve the multi-variable coupling control problem of single-reactor and double-turbine nuclear power system,the structure of 3*3 multi-variable controlled system is established in this paper.Then the inverse Nyquist array method is used to realize the decoupling of each control loop,and the controller of each loop is designed based on the PI method.Simulation results show that the INA method has a certain degree of decoupling,but the control effect is not greatly improved.To this end,a coordinated control strategy based on multivariable MPC method for marine single-reactor and double-turbine nuclear power plant is proposed.The simulation results show that,compared with the traditional PID controller,the multivariable MPC method proposed in this paper can better solve the coupling problem between loops,and can better achieve the control target of the system to track the load quickly.