Saulo López Fregoso's thesis defense

This thesis focuses on the robust control of on-board alkaline electrolyzers in order to improve the performance and reduce the environmental impact of spark-ignition thermal engines.

Conducted as part of an industrial collaboration, this research aims to overcome the limitations of current on-board hydrogen systems, notably the lack of closed-loop control and their sensitivity to operational hazards.

The study presents a comprehensive methodological framework, from theoretical modeling to experimental validation.

Firstly, a control-oriented "grey box" model has been developed to capture the coupled electrochemical and thermal dynamics of the system. Based on this representation, two robust control architectures, Active Disturbance Rejection Control (ADRC) and Disturbance Observer-Based Control (DOBC), have been designed to ensure accurate current tracking and disturbance rejection.

At the same time, the control system has been designed to provide a robust, robust control architecture.

Secondly, a major contribution of this work lies in the development of a specialized test rig, upgraded to allow separate gas injection and full signal monitoring. This experimental set-up has enabled a precise correspondence to be established between engine operating points (RPM/throttle opening) and the optimum hydrogen injection flow rate, serving as a reference for the control loop.

Secondly, a major contribution of this work lies in the development of a dedicated test rig, upgraded to allow separate gas injection and full signal monitoring.

Finally, real-time validation demonstrated that the proposed closed-loop strategies significantly outperform traditional open-loop methods. The system successfully stabilized hydrogen production during transient regimes, leading to a substantial improvement in the engine's environmental performance. The results showed a reduction in NOx emissions from 50 to 200 ppm and a steady decrease in unburned hydrocarbons (HC) by an equivalent amount, thus proving the effectiveness of these strategies, viability of on-board, rigorously controlled hydrogen production for the decarbonization of the automotive sector.

Reporters:

• Mrs. Lydie NOUVELIÈRE, Professeur des Universités, Laboratoire LASPI, Télécom Saint-Etienne, Université Jean Monnet, France
• Mr. Guillaume COLIN, Professeur des Universités, PRISME/ECM-Polytech Orléans, France

Examiners:

• Mr. Abdelhamid RABHI, Professeur des Universités, Laboratoire MIS - UFR des sciences, Université de Picardie Jules Verne, France

Thesis supervisor:

• Mr. Jimmy LAUBER, University Professor, Université Polytechnique Hauts-de-France, INSA Hauts-de-France , France

Co-Encadrant:

• Mr. Denis BERDJAG, Senior Lecturer, Université Polytechnique Hauts-de-France, France
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