Control Of CFB Boiler Bed Temperature And Main Steam Pressure Based On Ant Colony PID And Fuzzy Rules

Circulating fluidized bed boiler has the advantages of environmental protection,energy saving,wide fuel adaptability and high combustion efficiency.It has been widely used at home and abroad at present.But its combustion system has the characteristics of nonlinear,large time delay,strong coupling and so on.Therefore,the control effect in the field has not been ideal.The most widely used is the traditional PID controller,but the setting of traditional PID parameters needs to be artificially adjusted,it is difficult to adjust to the best control state.Therefore,it is necessary to further study the control of the combustion system of CFB boiler.After analyzing the current research situation of CFB boiler combustion control system at home and abroad,the paper finds out the problems in the control of CFB boiler combustion system,and use the experimental modeling method to get the mathematical model of the bed temperature and main steam pressure according to the historical data collected during the actual production of a power plant.Use the diagonal matrix decoupling method to decouple the two controlled objects,and use ant colony algorithm with the feature of division of labor to optimize the three parameters Kp,Ki,Kd in the PID controller.Ant colony algorithm is a kind of bionic evolutionary algorithm,which has the characteristics of distributed parallel computing.By introducing the concept of division of labor and innovation,the ant colony algorithm can improve its global convergence ability.By using the improved ant colony algorithm to optimize the parameters of PID controller,and then through the parameters optimized PID controller to achieve independent control of bed temperature and main steam pressure.Taking the circulating fluidized bed boiler combustion system is difficult to model an accurate mathematical model and the strong coupling effect between the bed temperature and the main steam pressure into account,the paper also puts forward fuzzy decoupling control scheme.The paper use two main fuzzy controller to control the bed temperature and main steam pressure,and use two fuzzy controllers as decoupling controller to decoupling the system.This ensures the decoupling of the system and control the bed temperature and main steam pressure at the same time.Taking the mathematical model in a typical working conditions of 300 MW circulating fluidized bed,build the simulation circuit on the Matlab simulation software platform to simulate the two control schemes respectively.Under the step signal disturbance,two schemes were compared with the traditional PID control scheme.Simulation results show that the improved ant colony algorithm is good to optimize PID control parameter,it can find out the best control parameters rapidly;And the fuzzy decoupling control method can realize the decoupling between bed and main steam pressure,at the same time both of the two kinds of control scheme have the advantages of quick response speed,and small overshoot amount when compared with traditional PID control.At the same time,after changing the parameters,adding the disturbance,a series of simulation of the two control schemes are carried out,which verify the robustness of the control scheme.