Cascade Smith Control of SCR Flue Gas Denitrification System Based on Active Disturbance Rejection

Abstract

Selective catalytic reduction (SCR) denitrification system has complex reaction process, which is characterized by large inertia, large delay, strong disturbance and uncertainty. In order to improve the robustness of traditional linear active disturbance rejection controller (LADRC), an improved active disturbance rejection controller (ILADRC) is designed by adding an identical linear extended state observer (LESO) and introducing the estimated error value of total disturbance. In order to better solve the problem of large delay in SCR denitrification system, Smith predictor is used to offset the delay of output variables before entering LESO. Smith-ILADRC control of SCR denitrification system is designed. The tracking performance, anti-jamming performance and robustness of Smith-ILADRC are simulated under the action of external disturbance and the change of model parameters. The results show that the tracking performance and anti-jamming ability of Smith-ILADRC are obviously improved.