Input-Compensated Active Disturbance Rejection Control Design for Circulating Fluidized Bed Boiler Combustion System

Circulating fluidized bed boilers (CFBBs) are widely applied in energy, metallurgy, the chemical industry and other fields, mainly due to their high combustion efficiency and low pollution emissions. However, the CFBB combustion system, as a typical third-order plus time delay (TOPTD) system, has inherent characteristics: large inertia, significant time delays and strong coupling. Coupled with the difficulty in establishing an accurate mathematical model, traditional control methods struggle to achieve the desired control performance. Active disturbance rejection control (ADRC) has prominent advantages, such as low dependence on the controlled plant’s accurate model and strong disturbance rejection ability, but it has obvious limitations in dealing with systems with large inertia and large time delays. To address this problem, this paper proposes an input-compensated active disturbance rejection control (ICADRC) method. An input-compensated part composed of a second-order inertial link and a time delay link is introduced into the ESO input channel, which is specially optimized for the characteristics of TOPTD systems. A set of quantitative parameter tuning rules unique to ICADRC is established via the equivalent approximation method, and a dedicated MATLAB auto-tuning toolbox for ICADRC is developed for TOPTD systems. Simulation experiments are conducted on the CFBB combustion system, and the results show that the proposed ICADRC exhibits superior setpoint tracking performance, disturbance rejection performance and robustness compared with ADRC, DADRC, and SIMC-PI. Under nominal operating conditions, the IAEsum of ICADRC is reduced by 36.2% relative to DADRC and by 54.3% relative to SIMC-PI. Specifically, under fixed parameter perturbations, the variation amplitude of ICADRC’s performance index is only 2.1%, significantly lower than the 5.1% for DADRC, 6.1% for ADRC, and 7.3% for SIMC-PI.