Nonlinear model predictive control methodology for efficiency and durability improvement in a fuel cell power system

The main contribution of this work is the improvement of the efficiency of a PEMFC power system while guaranteeing conditions that also improve its durability. Adopting the NMPC scheme with the distributed parameter model and the nonlinear observer, the efficiency of the PEMFC-based system can be maximized guaranteeing at the same time the appropriate internal gas concentration profiles to avoid global and local hydrogen and oxygen starvation and proper membrane humidification.Peer ReviewedPostprint (author's final draft

Nonlinear predictive control for durability enhancement and efficiency improvement in a fuel cell power system

© . This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/In this work, a nonlinear model predictive control (NMPC) strategy is proposed to improve the efficiency and enhance the durability of a proton exchange membrane fuel cell (PEMFC) power system. The PEMFC controller is based on a distributed parameters model that describes the nonlinear dynamics of the system, considering spatial variations along the gas channels. Parasitic power from different system auxiliaries is considered, including the main parasitic losses which are those of the compressor. A nonlinear observer is implemented, based on the discretised model of the PEMFC, to estimate the internal states. This information is included in the cost function of the controller to enhance the durability of the system by means of avoiding local starvation and inappropriate water vapour concentrations. Simulation results are presented to show the performance of the proposed controller over a given case study in an automotive application (New European Driving Cycle). With the aim of representing the most relevant phenomena that affects the PEMFC voltage, the simulation model includes a two-phase water model and the effects of liquid water on the catalyst active area. The control model is a simplified version that does not consider two-phase water dynamics.Peer ReviewedPostprint (author's final draft

Proton exchange membrane fuel cell degradation prediction based on Adaptive Neuro-Fuzzy Inference Systems .

International audienceThis paper studies the prediction of the output voltage reduction caused by degradation during nominal operating condition of a PEM fuel cell stack. It proposes a methodology based on Adaptive Neuro-Fuzzy Inference Systems (ANFIS) which use as input the measures of the fuel cell output voltage during operation. The paper presents the architecture of the ANFIS and studies the selection of its parameters. As the output voltage cannot be represented as a periodical signal, the paper proposes to predict its temporal variation which is then used to construct the prediction of the output voltage. The paper also proposes to split this signal in two components: normal operation and external perturbations. The second component cannot be predicted and then it is not used to train the ANFIS. The performance of the prediction is evaluated on the output voltage of two fuel cells during a long term operation (1000 hours). Validation results suggest that the proposed technique is well adapted to predict degradation in fuel cell systems

Analyse des mécanismes de dégradation dans un système pile à combustible

International audienceLes systèmes pile à combustible (SPàC) sont considérés comme une solution viable et une alternative prometteuse autant pour des applications embarquées que stationnaires. Cela dit, ces systèmes doivent répondre à des critères essentiels à leur large développement, à savoir, coût, durabilité et fiabilité. Le présent travail se focalise sur l’aspect fiabilité du système pile à combustible. En effet, une meilleure compréhension des mécanismes de dégradation dans le SPàC permettra de développer les stratégies nécessaires à la réduction des dégradations au sein du SPàC et augmenter sa durée de vie utile. Une analyse des mécanismes de dégradation et leurs effets au niveau du SPàC a été faite dans le but de construire un arbre de défaillances le plus complet possible. Le SPàC étudié comprend le stack (membrane, couche catalytique, plaques bipolaires, couche de diffusion des gaz) le système d’alimentation en air (compresseur, capteurs, régulateurs, électrovannes), le système d’alimentation en hydrogène (capteurs, régulateurs, électrovannes) et le système de refroidissement (pompe de circulation, capteurs, électrovannes, régulateurs). Cette étude permettra de déduire les lois de propagation des défauts dans le SPàC qui permettront une meilleure estimation de sa durée de vie

Degradation aspects of water formation and transport in Proton Exchange Membrane Fuel Cell: A review

This review paper summarises the key aspects of Proton Exchange Membrane Fuel Cell (PEMFC) degradation that are associated with water formation, retention, accumulation, and transport mechanisms within the cell. Issues related to loss of active surface area of the catalyst, ionomer dissolution, membrane swelling, ice formation, corrosion, and contamination are also addressed and discussed. The impact of each of these water mechanisms on cell performance and durability was found to be different and to vary according to the design of the cell and its operating conditions. For example, the presence of liquid water within Membrane Electrode Assembly (MEA), as a result of water accumulation, can be detrimental if the operating temperature of the cell drops to sub-freezing. The volume expansion of liquid water due to ice formation can damage the morphology of different parts of the cell and may shorten its life-time. This can be more serious, for example, during the water transport mechanism where migration of Pt particles from the catalyst may take place after detachment from the carbon support. Furthermore, the effect of transport mechanism could be augmented if humid reactant gases containing impurities poison the membrane, leading to the same outcome as water retention or accumulation. Overall, the impact of water mechanisms can be classified as aging or catastrophic. Aging has a long-term impact over the duration of the PEMFC life-time whereas in the catastrophic mechanism the impact is immediate. The conversion of cell residual water into ice at sub-freezing temperatures by the water retention/ accumulation mechanism and the access of poisoning contaminants through the water transport mechanism are considered to fall into the catastrophic category. The effect of water mechanisms on PEMFC degradation can be reduced or even eliminated by (a) using advanced materials for improving the electrical, chemical and mechanical stability of the cell components against deterioration, and (b) implementing effective strategies for water management in the cell

Towards Resilient Fuel Cell Systems

International audienceHydrogen &amp; Fuel Cell systems are very promising clean systems to store intermittent energy and use it in green and decentralized electricity. For the large-scale deployment of these innovative hydrogen-based technologies, it is necessary to bring reliable systems to the market with competitive costs and lifetimes. For this purpose, solutions for tolerance to fault and resistance to degradation shall be developed. <br&gtThe solutions of interest are based mainly on analytical redundancy and are integrated into the system, using as much as possible, the system’s own resources. Thus, the stack is used as its own sensor. The different solutions developed include monitoring, diagnosis, prognosis, decision and control. The PEMFC system developed has the properties of resilient systems.&nbsp

Towards Resilient Fuel Cell Systems

International audienceHydrogen &amp; Fuel Cell systems are very promising clean systems to store intermittent energy and use it in green and decentralized electricity. For the large-scale deployment of these innovative hydrogen-based technologies, it is necessary to bring reliable systems to the market with competitive costs and lifetimes. For this purpose, solutions for tolerance to fault and resistance to degradation shall be developed. <br&gtThe solutions of interest are based mainly on analytical redundancy and are integrated into the system, using as much as possible, the system’s own resources. Thus, the stack is used as its own sensor. The different solutions developed include monitoring, diagnosis, prognosis, decision and control. The PEMFC system developed has the properties of resilient systems.&nbsp

Towards Resilient Fuel Cell Systems

International audienceHydrogen &amp; Fuel Cell systems are very promising clean systems to store intermittent energy and use it in green and decentralized electricity. For the large-scale deployment of these innovative hydrogen-based technologies, it is necessary to bring reliable systems to the market with competitive costs and lifetimes. For this purpose, solutions for tolerance to fault and resistance to degradation shall be developed. <br&gtThe solutions of interest are based mainly on analytical redundancy and are integrated into the system, using as much as possible, the system’s own resources. Thus, the stack is used as its own sensor. The different solutions developed include monitoring, diagnosis, prognosis, decision and control. The PEMFC system developed has the properties of resilient systems.&nbsp

Un cursus d’excellence pour former des ingénieurs-experts en matière d’hydrogène-énergie

National audienceLauréat du programme «&nbsp;Initiatives d’excellence en formationsinnovantes&nbsp;» mis en place par le gouvernement en 2012, lecursus Master en ingénierie (CMI) du réseau FIGURE a conduit à unetransformation profonde et durable des universités tant en termesde pratiques d’enseignement qu’en termes de qualité des formationsdispensées. Le CMI H3E est l’un de ces cursus&nbsp;; il a été crééen 2014 à l’Université de Franche-Comté pour former des cadresscientifiques et techniques aux métiers de l’hydrogène, desétudiants devant faire preuve de capacités d’innovation et d’uneouverture sociétale renforcées.<br /&gtBénéficiant d’un écosystème Formation-Recherche-Industrieexceptionnel ‒ deux grands laboratoires pionniers dans le domainede l’hydrogène, un tissu industriel fortement impliqué, une régionlabélisée «&nbsp;Territoire Hydrogène&nbsp;» dès 2016 et uneuniversité qui compte l’hydrogène parmi ses thèmes prioritaires deformation ‒, le CMI H3E œuvre à proposer une formation d’excellencepour une filière en plein essor. Il s’appuie pour cela sur uneoffre de formation se déclinant en deux masters (en ingénierieélectrique et en ingénierie thermique) et sur un corps professoralconstitué d’experts reconnus