THE FUZZY CONTROLLER SYNTHESIS TO CONTROL THE RATIO OF RATES “GAS – AIR” ON THE BASIS OF THE REGIME MAP

Abstract

Gas combustion process takes place under real conditions with air excess. With increasing excessive air above the recommended quantity heat loss increase due to the cold air inflow. Airflow is nonlinearly dependent on several factors. In practice, the non-linear dependences are taken into account by the regime maps and gas analyzers. If during the adjustment according the indications of gas analyzers gas or air pressure in the furnace will differ from regime map more than 10 percent, then control loop according the indications of gas analyzers automatically shut off and gas and air pressure control will take place by the regime map. when controlling the combustion process on regime maps all possible temperature range is divided into intervals. When controlling the combustion process by regime maps all possible temperature range is divided into intervals. In this case, because of the discrete steps of temperature and gas flow rate it is necessary to provide some supply of air excess to ensure complete gas combustion. In this paper the synthesis of fuzzy controller (FC) for gas combustion process control has been described, which taking into account the fluctuations of the following factors: gas flow rate, temperature, pressure and humidity of air. Fuzzy controller provides at the output the required air flow. The synthesis of fuzzy controller includes the following tasks: creating a reference points table on the basis of the regime map, selection of input and output linguistic variables terms, selection of the structure and constructing algorithm for production rules, synthesis database of production rules with two consequent, fuzzy controller simulation, the error calculation. The static characteristic of FC is a smooth surface constructed by the reference points with the required accuracy. Smoothness of change provides optimal control. Optimality criterion is to ensure the highest possible efficiency and to minimize gas consumption.