Multi-objective optimization based fractional order model-free controller for boiler drum system

Boiler drum system with time-varying characteristics is a complex industrial plant and has attracted more and more attention. Advanced control theory focusing time-varying characteristics and low complexity is necessary in the boiler system operation. However, several model-based methods are so limited by the model accuracy that they can´t be applied in the real devices very well. In order to solve this problem, the model-free control (MFC) is used to provide the ability of disturbance rejection and robustness. By combining MFC with fractional calculus, the control performance is improved. A new approach called fractional order model-free control (FOMFC) is developed in this paper for boiler drum system. A series of FOMFCs are explored to compare with the MFC and PID controller. Multi-objective optimization is used in the design of FOMFCs for a boiler drum level system. Comprehensive analysis and simulation results on a boiler system show the effectiveness of the FOMFC controller.