Fuzzy rule-based combustion control on air adjustment applied to a coal fired power plant

Fuzzy modelling and control is a technique to handle qualitative information in a formal, rigorous and efficient way if such information is properly used. In this paper it is presented an alternative fuzzy logic rule-based method to correct the excess air flow to the combustion furnace of a large coal fire boiler. The developed algorithm for decision on the control variable is based on the knowledge of the processing task by measuring the error variables, carbon monoxide and oxygen from exhaust gas, is particularly emphasized, being the goal of these papers. Such algorithm exploits the knowledge of a rule-base created under fuzzy ideas to be defuzzified by means of a least squares method. The input variables to the rule base are the oxygen and carbon monoxide which result from the combustion. The output from defuzzification process is the excess in air flow to be added to the ratio relay output, operating in feedforward mode