Performance Evaluation And Analysis Of Various PID Control Systems For Water Level Of Steam Generator In Nuclear Power Plant

The steam generator is a highly nonlinear time-varying system.Under different power levels,linear dynamic models can be obtained.However,when the reactor power changes,the parameters in these linearized models will also change significantly.As the most important equipment in nuclear power plant,the water level control of steam generator has always been the focus of research in recent years.The instability of system parameters under low power and the phenomenon of"false water level"under large load change all increase the difficulty of designing control system.With the continuous improvement of safety and stability requirements and the development of control theory in nuclear power plants,higher requirements are put forward for the water level control system of steam generators.The rapid development of computer technology greatly promotes the rapid development of system simulation.The emergence of some software makes the simulation process become easy to realize and has high fidelity and effectiveness.Firstly,a polytopic LPV model of steam generator water level control is established,and the causes of false water level are analyzed.Secondly,based on the traditional PID controller,this paper designs a single PID controller,a cascade integer order PID controller and a cascade fractional order PID controller.The performance of the system was analyzed based on the maximum offset,the adjustment time and the Mean Square Error(MSE)of the system,and the comparison and compared the control performance.Then,two kinds of intelligent algorithms,genetic algorithm and particle swarm optimization algorithm,are used to optimize the PID parameters.The simulation results show that the controller set by the intelligent algorithm has smaller overshoot and shorter adjustment time.Finally,based on linear matrix inequality,in this paper,the proportional type H_∞static output feedback controller and the proportional differential type H_∞static output feedback controller are designed respectively.The simulation results show that the controller satisfies the requirements of H_∞.At the same time,through the analysis of its maximum offset,adjustment time and MSE,the two control systems have high reliability and good control performance,and at the same time,the structure is simple,easy to implement,is an effective control strategy suitable for engineering application.