Control Strategy And Simulation Of Boiler Drum Water Level Based On MATLAB/SIMULINK

Boiler drum water level control is very important in boiler automatic controlsystem, its control effect is directly affect the quality of the boiler water’s supply,and ultimately affect the boiler’s safe production. Boiler drum water level controlsystem is hard to develop practical mathematical model, and has nonlinear, stableand delay sexual characteristics. The traditional boiler drum water level controloften uses three-impulse PID control method. The existing problem of ordinary PIDcontrol strategy is: once good parameter setting, it is hard to adapt to the change ofthe operation of the system dynamic greatly.In order to solve the problems of the above, the research object of the subject isa certain120t/h boiler steam capacity, the boiler drum water le vel control system isdesigned, and the control strategies are studied. In order to obtain better contrast, theordinary PID controller and fuzzy controller and the fuzzy adaptive PID controllerare designed, and the control strategies of the simulation ar e analyzed. Consideringthe fuzzy adaptive PID controller exists some shortage, the variable domain thoughtis introduced and the variable domain adaptive fuzzy PID controller is designed。Through the analysis of the controller, the results show that the co ntroller is betterthan other controllers in performance, and can satisfy the boiler drum water levelcontrol requirements.First of all, referring to the domestic and foreign literature review on boilerdrum water level control, the drum water level contr ol system are designedaccording to the boiler system parameters and control requirements. Through thereasonable deduction, the boiler drum water level control system of nonlinearmathematical model is established, and the system stability is analyzed by using themethod of frequency domain Byrd figure and Nichols figure.Secondly, in view of the system without any controller existing slow response,the ordinary PID controller is designed. Although common PID control regulationcan reduce system dynamic deviation and adjust the time quickly, and improve theprocess of dynamic quality, once the parameters are set, it is hard to adapt to thesystem dynamic change of operation greatly.Then, the ordinary fuzzy controller and the fuzzy adaptive PID controller a redesigned according to fuzzy control concept. The analysis of system simulationshows that the two controller control effect is obvious better than ordinary PIDcontroller in the overshoot and velocity response. Finally, based on fuzzy adaptive PID control, a variable domain adaptive fuzzyPID controller is designed by introducing the variable domain thought. Through thesystem simulation analysis, the results show that the controller are shorter responsetime and more small overshoots than the fuzzy adaptive PID controller, and canimprove the control precision of the system under no increase control rules，and canmore satisfy the boiler drum water level control requirements.