Study On The Fuzzy Control For The Industry Coal-fired Boiler

The problem of automatic control in coal-fired boiler is discussed in this thesis. A type of coal-fired boiler inflammation system is regarded as the research target, after separately analyzed steam pressure loop and water level loop, we obtained the relevant control scheme, and designed a kind of fuzzy-PI compound controller to control two loops.First, the technological process and characteristic of industry coal-fired boiler is analyzed, and this paper gives simply the main mission of automatic control of coal-fired boiler inflammation system, and introduced actual ordinary control laws of boiler inflammation system study, along with fuzzy control system development and application in the control engineering. Afterwards on based of analyzing coal-fired boiler inflammation system technological process and work process, the coal boiler inflammation system control scheme is designed. Then, this paper introduced the fundamental theory base and design means of fuzzy controller, and gives fundamental design process of it.Second, the dynamic characteristic of the loop for steam pressure is analyzed, on the basis of this, a routine PI controller is designed to control the steam pressure. But for the complexity of boiler, it is difficult to obtain accurate mathematical model, the controller is not so effective. Then a fuzzy control system is designed on the basis of the characteristic of boiler, though the dynamic quality is improved, there is static error. After that combining the excellence of routine PI controller and fuzzy controller, an fuzzy-PI controller is designed. It works well in practice. According to the same method, an fuzzy—PI controller is designed used to steam pressure.Third, according to the principle of economic combustion and the reason of low efficiency, an economic combustion fuzzy control system is designed, which can satisfy system control demand. At last, after the fundamental use means of fuzzy control tool kit below the MATLAB is introduced, using it has a simulation study on the coal boiler inflammation system, and gives several simulation curves and gains conclusion.