Design and Simulation of Cascade Fuzzy Control System for Boilers

Abstract

The control of boiler drum water level plays an important role in the automation control of boilers, the control effect directly affects the safety production of the boiler. In order to solve problems of non-linearity, instability and time-delay of boiler drum water level control system and difficulty in establishing accurate mathematical model, a feedforward-cascade three-flush boiler water level control system is designed, the Simulink control simulation system is established, and the control system is simulationed in the MATLAB environment, parameters of PID is determined according to engineering setting method, considering the PID controller exists some shortage,the adaptive fuzzy PID controller is designed and simulationed. The results of the system simulation analysis indicate, the three-pulse cascade and feedforward water level control system can effectively eliminate the load (steam amount) change and the disturbance of the feed water flow fluctuation, fuzzy adaptive PID has shorter response time and smaller overshoot than PID controller, to make the control water level meet the stable-operational requirement with high qualituy and accuracy, and can more satisfy the boiler drum water level control requirements.