Active disturbance rejection control for bed temperature of circulating fluidized bed boiler based on multivariable internal model structure

Circulating fluidized bed (CFB) boilers, which have the advantages of burning inferior coal and high desulfurization efficiency, have been the key component of Chinese thermal power installed capacity. However, compared with the pulverized coal-fired boiler, the combustion control of CFB boiler is more complicated because of the larger time delay, long inertia time and more coupled variables. Bed temperature is a peculiar parameter in the combustion process of CFB boiler, which has an important impact on the safety, economy and emission. In this paper, a novel bed temperature control strategy based on active disturbance rejection theory was presented to improve the combustion performance of CFB boiler. By introducing the multi-variable internal model control structure, the parameter of the extended state observer and feedback controller was tuned and designed, and the optimal control performance of the system was achieved. Theoretical analysis and simulation results show that the proposed strategy is handy for parameter tuning and dynamic characteristic analysis. It does not rely on accurate combustion process models, and has satisfactory load adaptability and anti-disturbance ability. © 2017 Chin. Soc. for Elec. Eng.