Linear active disturbance rejection decoupling control of circulating fluidized bed boiler´ combustion system

The circulating fluidized bed boiler´ combustion system, is a multivariable system, characterized by large time lag, long time-delay and strong coupling, thus many control methods can´t achieve effective control. In this paper, a novel scheme for the circulating fluidized bed boiler´ combustion system was presented based on the principle of linear active disturbance rejection control (LADRC) and dynamic decoupling compensator. A decoupling compensator based on the circulating fluidized bed was designed, which could capture the essential dynamics and cross-coupling, then the model of decoupling compensator is simplified according to the invariance principle, finally the LADRCs were designed separately to further reduce the coupling by taking it as disturbance. Since LADRC estimated real-time disturbance via extended state observer (ESO), it can eliminate disturbance quickly via a disturbance compensator independent of the accurate mathematical model of the plant. The method was applied to a circulating fluidized bed boiler´ combustion system and the results show that it can provide better decoupling, stronger robust ability and disturbance rejection than PID.