Synergetic Control of Cascade-Configured Anaerobic Digestion Bioreactors for Enhanced Hydrogen Production

Authors

O. Messili, S. Semcheddine, A. Chaabna

Abstract

This work introduces, for the first time, a synergetic control law within a cascade control structure tailored to the dynamics of anaerobic bioreactors for hydrogen generation. This novel integration addresses the challenges of biological system nonlinearities, input saturation, and stability under disturbance, offering a promising alternative to traditional PID-based strategies. To assess the effectiveness of the proposed approach, simulation studies were conducted in the Matlab/Simulink environment using a validated dynamic model from the literature. A comparative analysis with a classical PID controller optimized via genetic algorithms (GA-PID) was also carried out. The proposed synergetic controller achieved the desired hydrogen outflow rate within 1.1 hours, representing a 78.4 \% improvement in response time compared to the GA-PID controller (5.1 hours). Furthermore, the synergetic controller maintained closed-loop stability under input saturation (D₁), effectively handled external disturbances and sensor noise, and provided consistent tracking performance without biomass washout. These results demonstrate the superior precision, robustness, and convergence speed of the proposed method in regulating hydrogen production under realistic constraints.

Keywords

Cascade bioreactors, Synergetic control, Non linear control, Hydrogen, Methane, Waste recycling.