APPLICATION OF DUAL CLOSED LOOP FUZZY CONTROL IN BURNING CONTROL SYSTEM OF BOILER

摘要

A dual closed loop fuzzy control system with intelligent integral-tuning unit is structured, which takes the radiant energy of flame in furnace that could rapidly reflect the change of fuel flow as an intermediate controlled parameter in view of the facts that the burning process is so complicated that it is ill-defined by an accurate mathematical model and there are the nonlinear, intensive inertial characteristics with large time-delay in the channel from flue to pressure. The paper detailedly introduces the characteristic of dual closed loop fuzzy controllers and the functions of intelligent integral-tuning unit. The result of simulations show that the structure designed is able to eliminate the disturbance of fuel flow in time, dominate efficiently the fluctuation of steam pressure, and ameliorate the control quality of steam pressure because of the adoption of the intermediate controlled signal -radiant energy. At the same time, the system obviously decreases steady error, which is one of the main shortcomings of the traditional fuzzy controller, and avoids integral saturation.