Linear active disturbance rejection controllers (LADRC) for boiler-turbine units

Linear active disturbance rejection control (LADRC) is shown to be a simple and effective method as a substitute of conventional PID control. Nevertheless, the tuning of the LADRC parameters needs some experience, especially for multivariable systems. Boiler-turbine units are widely used in power generation industry, and are typical multivariable systems with strong coupling, nonlinearity, large time delay and large inertia. In this paper, an LADRC scheme is proposed for boiler-turbine units which compromises a decoupling compensator and two SISO linear active disturbance rejection controllers. The compensator helps reduce the strong coupling between the two outputs and two LADRCs further reduce the external disturbances and model uncertainties. Since LADRC can estimate the disturbances via extended state observer (ESO), it will eliminate the disturbance quickly independent of the accurate mathematical model of the units. Simulation results show that the LADRC structure for boiler-turbine units can achieve good decoupling and good disturbance rejection with robustness, and it is easy to tune and implement in practice.