Composited active disturbance rejection control for the coordinated system of supercritical unit

Directing against the nonlinear, variable-parameter, strong-coupling, and large time-delay features of the supercritical boiler-turbine unit, which often participates in peak regulation and frequency modulation in meeting the power grid demands, this paper analyzes the characteristics of the coordinated control system for a 600MW supercritical power unit, and designs the composited active disturbance rejection controllers (LADRC) for load and main steam pressure control based on “boiler following turbine base” coordinated control mode. Extended state observers are used to estimate the unmodeled dynamic and unknown disturbance in real time, to eliminate coupled disturbance influence rapidly and to achieve decoupling of the coordination system. Feed-forward signals are introduced into boiler LADRC and turbine LADRC to deal with static coupling and time delay. The LADRCs are programmed in Matlab, and load-changing disturbance tests with LADRCs and original PID controllers are respectively carried out on the full-scope simulator of the given supercritical power unit. The test result shows that the anti-disturbance control effect of LADRCs for load and main steam pressure is significantly better than the PID controllers. This LADRC algorithm with less parameters tuning is simple, and easy applied in engineering.