An Intelligent Supervisory System for the Thermal Process during Severe Disturbance

The boiler system is a MIMO system with the characteristics of nonlinear dynamics, with there being severe loading variation, the boiler variables such as steam pressure and water level under go some major fluctuations. Such fluctuations are difficult to minimize using classical control techniques. In response to these circumstances, this paper contributes a methodology to design a two-level structure control method to improve the performance of the boiler response during such disturbance, in which the direct level consists of a predictive PID controller based on DCS(Distributed control systems); and the set-points of the drum steam pressure and the water level deviation are modified whenever necessary by a supervisor partially based on fuzzy theory according to the current operation condition. Finally, the good performance of the two-level control method is demonstrated through numerical experiments.