On the Extremum-Seeking Control Design and Application for Anaerobic Digestion Processes

Abstract

The paper deals with the optimization of nonlinear systems by using Extremum Seeking Control (ESC) without any prior knowledge of the system model. An Extend Kalman Filter based Extremum Seeking Control (EKF based ESC) is proposed, which can make the amplitude of perturbation signal variable and ensure convergence to zero, i.e. without steady-state oscillation. The proposed ESC algorithm makes also possible to obtain more accurate gradient estimate and more rapid ESC convergence. The proposed EKF based ESC algorithm is applied to a fifth-order model of anaerobic digestion process and its performances are compared with the performances of the classical ESC algorithm.

Volumes Ratio Optimization in a Cascade Anaerobic Digestion System Producing Hydrogen and Methane

“…flow rates present extrema (maxima) in the admissible range of the control input (D 1 ) for different values of the main perturbation -in 0 S [12,14,15]. The new idea for calculating the optimal ratio of the working volumes of both bioreactors is based on the possibility to assure operating of both bioreactors in the points of maximal biogas (hydrogen and methane) production:…”

“…The volumes of the bioreactors are presented separately but without discussing the ratio between them. Previous experimental studies of co-digestion of mixtures of milk whey and waste activated sludge in a TSAD process and modelling of this processes have been conveyed by us, where methane is obtained from both bioreactors as well as extremum-seeking control design and application for anaerobic digestion processes [14].…”