Model reference fuzzy adaptive controller for combustion of utility boiler

A novel design for combustion control of utility boiler using model reference fuzzy adaptive controller is proposed. The main objective of the combustion controller in a thermal power plant is to regulate fuel and air in proper ratio to maintain the desired steam pressure at the turbine inlet irrespective of the changes in steam demand. The existing control schemes have difficulty to cope up with inherent time delay, non-linearity due to uncertainty of the combustion process and frequent load changes. This paper presents a model reference fuzzy adaptive controller approach in the design of fuzzy controllers to regulate fuel and air for the combustion process in a utility boiler. The on line adaptive fuzzy reference model for fuel is presented by calculating the adaptive error factor as per the boiler dynamics considering steam pressure to the turbine inlet and turbine first stage pressure. Adaptive fuzzy reference model for air is presented by measuring oxygen in the flue gas path. An experimental setup is fabricated in the laboratory for fuel and air control and simulation studies were carried out using three-control strategies, namely conventional PID, conventional FLC and model reference fuzzy adaptive controller scheme. Detailed experimental data was obtained from the thermal power plant to validate the controller's performance. The advantages of the proposed design upon the existing controller are highlighted.