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    Distributed parameter PEMFC model order reduction  Open access

     Sarmiento Carnevali, Maria Laura; Batlle Arnau, Carles; Serra Prat, Maria; Massana Hugas, Immaculada
    Congreso Iberoamericano de Hidrógeno y Pilas de Combustible
    p. 45-48
    Presentation's date: 2014-10-16
    Presentation of work at congresses

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    This work focuses on obtaining an order-reduced model from a nonlinear single PEMFC model, which incorporates the effects of distributed parameters that are relevant for its proper functioning and performance. The original model is an in-house MATLAB code, flexible enough to manipulate the underlying model equations and apply model order reduction (MOR) techniques. The obtained order-reduced model is suitable to perform numerical simulations and design efficient controllers for the original nonlinear partial differential equations (PDE) model.

    This work focuses on obtaining an order-reduced model from a nonlinear single PEMFC model, which incorporates the effects of distributed parameters that are relevant for its proper functioning and performance. The original model is an in-house MATLAB code, flexible enough to manipulate the underlying model equations and apply model order reduction (MOR) techniques. The obtained order-reduced model is suitable to perform numerical simulations and design efficient controllers for the original nonlinear partial differential equations (PDE) model.

  • Distributed parameter model simulation tool for PEM fuel cells

     Sarmiento Carnevali, Maria Laura; Serra Prat, Maria; Batlle Arnau, Carles
    International journal of hydrogen energy
    Vol. 39, num. 8, p. 4044-4052
    DOI: 10.1016/j.ijhydene.2013.04.015
    Date of publication: 2014-03-06
    Journal article

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    In this work, a simulation tool for proton exchange membrane fuel cells (PEMFC) has been developed, based on a distributed parameter model. The tool is designed to perform studies of time and space variations in the direction of the gas channels. Results for steady-state and dynamic simulations for a single cell of one channel are presented and analyzed. Considered variables are concentrations of reactants, pressures, temperatures, humidification, membrane water content, current density, among others that have significant effects on the performance and durability of PEMFC. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

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    Order reduction of a distributed parameter PEM fuel cell anode gas channel model  Open access

     Sarmiento Carnevali, Maria Laura; Batlle Arnau, Carles; Massana Hugas, Immaculada; Serra Prat, Maria
    European Hydrogen Energy Conference
    p. 265-272
    Presentation's date: 2014
    Presentation of work at congresses

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    Distributed parameter modeling is required to accurately consider space variations, which are important regarding the performance and durability of the Proton Exchange Membrane Fuel Cells (PEMFC) [1-3]. However, the number of differential and algebraic equations (DAE) obtained from the discretization of a set of partial differential equations (PDE) is very large, and this not only slows down the numerical simulations, but also complicates the design of online model-based controllers. The inclusion of complex DAE models within model-based control schemes requires a previous simplification. A method to simplify complex models consists of reducing the order while preserving the relationship between certain input and output variables, determined from the control objectives. These Model Order Reduction (MOR) techniques have been extended to DAE systems [4]. This work focuses on obtaining an order reduced model, from a PEMFC anode gas channel PDE model, which incorporates the effects of distributed parameters that are relevant for the proper functioning and performance of PEMFC. The original model is an in-house MATLAB® code, flexible enough to manipulate the underlying model equations and apply MOR techniques. The obtained order-reduced model is suitable to perform numerical simulations and design efficient controllers for the original nonlinear PDE model.

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    Nonlinear predictive control for the concentrations profile regulation in a PEM fuel cell anode gas channel  Open access

     Luna Pacho, Julio Alberto; Ocampo Martinez, Carlos A.; Serra Prat, Maria
    European Control Conference
    p. 1807-1812
    DOI: 10.1109/ECC.2014.6862495
    Presentation's date: 2014
    Presentation of work at congresses

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    In this work, a nonlinear model predictive control (NMPC) strategy is proposed to regulate the concentrations of the different gas species inside a Proton Exchange Membrane Fuel Cell (PEMFC) anode gas channel. The purpose of the regulation relies on the rejection of the perturbations that affect the system. The model of the anode channel is derived from the discretization of the Partial Differential Equations (PDE) that define the dynamics of the system, taking into account spatial variations along the channel. Forward and backward discretizations of the distributed model are employed to take advantage of the boundary conditions of the problem. Simulation results are presented to show the performance of the proposed control method over a given case study. Different cost functions are compared and the one with minimum error is identified. Suitable dynamic responses are obtained facing the different considered disturbances.

    Postprint (author’s final draft)

  • State observers design for PEMFC systems

     Luna Pacho, Julio Alberto; Husar, Attila Peter; Serra Prat, Maria
    Ibero-American Conference on Hydrogen and Fuel Cells
    p. 1-4
    Presentation's date: 2014
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    This work presents the development of a nonlinear state observer to estimate the values of the different gas species concentration profiles in a Proton Exchange Membrane Fuel Cell (PEMFC) energy system. The selection of the estimated states is based on the functionality and performance of the observer. The implementation is based on the discretization of a PEMFC distributed 1+1D model. Forward and backwards discretization of the partial derivative equations is performed to take advantage of the boundary conditions of the problem. A second-order sliding-mode control super-twisting corrective input action is implemented to reduce the estimation error to zero in a finite amount of time. Simulation results are presented to show the performance of the observer to estimate the values of the states and to extract conclusions for future research work.// Este trabajo presenta el desarrollo de un observador de estados no lineal para la estimación de los perfiles de concentraciones en un sistema de energía basado en una Pila de Combustible de Membrana de Intercambio Protónico (PEMFC). La selección desempeño del observador. Las ecuaciones en derivadas parciales son discretizadas en dos sentidos un modelo 1+1D para aprovechar las condiciones de contorno del problema. Una acción de en métodos deslizantes de segundo orden es implementada para reducir el error de estimación a cero en un periodo finito de tiempo. Se presentan resultados de simulación para mostrar el rendimiento del observador reconstrucción de los valores de los estados y para extraer conclusiones para futuro trabajo de investigación.

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    Performance improvement by temperature control of an open-cathode PEM fuel cell system  Open access

     Strahl, Stephan; Perrier, Michel; Husar, Attila Peter; Riera Colomer, Jordi; Serra Prat, Maria
    International Conference on Fundamentals & Development of Fuel Cells
    p. 1-8
    Presentation's date: 2013-04
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    The work presented in this article combines experimental analysis and theoretical studies of temperature effects on the performance of an open-cathode, self-humidified PEM fuel cell system for the design of optimization strategies. The experimental analysis shows the great potential of improving the system performance by proper temperature management. The most significant temperature dependent parameters of the system under study are the activation polarization and the water content of the ionomer of the catalyst layer. An Extremum seeking control algorithm is proposed to regulate the temperature to a voltage maximum. However, the slow dynamics of the temperature related catalyst-drying effect on performance complicate the optimal thermal management via model-free control strategies.

  • Design of linear controllers applied to an ethanol steam reformer for PEM fuel cell applications

     García, Vanesa Mariel; Serra Prat, Maria; Llorca Pique, Jordi; Riera Colomer, Jordi
    International journal of hydrogen energy
    Vol. 38, num. 18, p. 7640-7646
    DOI: 10.1016/j.ijhydene.2012.11.078
    Date of publication: 2013
    Journal article

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    This paper focuses on the design of a controller for a low temperature ethanol steam reformer for the production of hydrogen to feed a Protonic Exchange Membrane (PEM) fuel cell. It describes different control structures for the reformer and treats the control structure selection of this Multiple Input Multiple Output (MIMO) system. For each control structure, decentralised 2x2 controllers with Proportional Integral (PI) control actions in each control loop are implemented. The PI parameters are tuned and the performance of the different linear controllers is compared through simulation. For the evaluation of the proposed controllers, the dynamic response for different initial conditions and changes in the references is analysed, as well as the behaviour of the controlled system against disturbances.

    This paper focuses on the design of a controller for a low temperature ethanol steam reformer for the production of hydrogen to feed a Protonic Exchange Membrane (PEM) fuel cell. It describes different control structures for the reformer and treats the control structure selection of this Multiple Input Multiple Output (MIMO) system. For each control structure, decentralised 2x2 controllers with Proportional Integral (PI) control actions in each control loop are implemented. The PI parameters are tuned and the performance of the different linear controllers is compared through simulation. For the evaluation of the proposed controllers, the dynamic response for different initial conditions and changes in the references is analysed, as well as the behaviour of the controlled system against disturbances.

    Postprint (author’s final draft)

  • Analysis of conventionally controlled PEMFC based on a distributed parameter model

     Sarmiento Carnevali, Maria Laura; Serra Prat, Maria; Batlle Arnau, Carles
    Iberian Symposium on Hydrogen Fuel Cells and Advanced Batteries
    p. 1
    Presentation's date: 2013
    Presentation of work at congresses

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    Observation of the internal states of a PEMFC anode gas channel  Open access

     Luna Pacho, Julio Alberto; Batlle Arnau, Carles; Kunusch, Cristian; Riera Colomer, Jordi; Sarmiento Carnevali, Maria Laura; Serra Prat, Maria
    Jornadas de Automática
    p. 1-8
    Presentation's date: 2013
    Presentation of work at congresses

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    In this work a non-linear, model-based state observer is developed. Dynamics of the system described by a distributed parameter, partial differential equations model. Forward and backward discretization of the model to take advantage of the boundary conditions. Simulation results are presented to show the performance of the observer. Comparison between the linear and nonlinear approaches of the observers.

    Postprint (author’s final draft)

  • Analyses of energy management strategies for a PEMFC/UC electric vehicle

     Bethoux, Olivier; Remy, G.; Riera Colomer, Jordi; Serra Prat, Maria; Azib, T.
    IEEE Vehicle Power and Propulsion Conference
    p. 956-961
    DOI: 10.1109/VPPC.2012.6422778
    Presentation's date: 2012-10
    Presentation of work at congresses

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    In this paper, two energy management strategies considering the hydrogen consumption of hybrid power sources using a PEM Fuel Cell (FC) and Ultracapacitors (UC) are described and compared. First, the Hybrid Electric Vehicle (HEV) architecture and the associated models with their control strategies are described. The two energy management strategies are evaluated based on the Energetic Macroscopic Representation (EMR). The comparison focuses on the global efficiency of the power sources energy management. In particular, a proposed strategy is to manage the UC State-OfCharge while stabilizing the FC around its maximal efficiency point. Finally, some simulations on a Fuel Cell / Ultracapacitors HEV show the differences between the compared control strategies.

  • Experimental characterization and diagonosis tools for proton exchange membrane fuel cells  Open access

     Primucci, Mauricio Ariel
    Institute of Industrial and Control Engineering (IOC), Universitat Politècnica de Catalunya
    Theses

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    A fuel cell is a device that gives electric power directly from electrochemical reduction and oxidation reactions. PEM fuel cells present some properties that make them appropriate for portable and transport applications: high efficiency, no emissions, solid electrolyte, low operating temperatures and high power density. However, some technical problems can be improved, durability of the materials and the appropriate control of the operating conditions. One important aspect of the operating conditions is the water management. The right water content is needed in the electrolyte and catalyst layers to maximize the efficiency of the PEMFC by minimizing the voltage losses. Water content in the fuel cell is given basically by the generation of the water in the cathode due to the reaction, the humidity of the inlet gases and the transport trough the membrane. This thesis studies, proposes and compares different experimental characterisation methods aimed to provide performance indicators of the PEMFC water state. A systematic use of Electrochemical Impedance Spectroscopy technique is presented and its results are studied in order to analyse the influence of different operating conditions over the PEMFC response. The variables under analysis include: load current, pressure temperature and gas relative humidity. All these variables are considered with inlet gases feeding: H2/O2 and H2/Air. A set of relevant characteristics from the EIS response has been considered. Several equivalent circuits has been analysed and those that have the best fitting with the experimental EIS data are selected. When air is used as oxidant, a simple equivalent circuit with a resistance and a Warburg element is proposed. When Oxygen is used as oxidant, a more complex equivalent circuit is needed. A detailed sensitive analysis is performed indicating those parameters that best capture the influence of the operating conditions. A new experimental characterisation technique, based on the inlet gases humidification interruption is proposed. This dynamic technique combines the information extracted from EIS and the temporal response in order to study the water transport and storage effects in the PEMFC. Two advantages of this proposed technique is the simple hardware configuration used and the relative low impact on the fuel cell response, making attractive the humidification interruption as an in-situ technique. Three different sets of performance indicators are proposed as diagnosis tool. Relevant Characteristics from the EIS response, if properly monitored, can give a diagnostic of the fuel cell internal state. After an analysis, the chosen ones are: low and high frequency resistances (RLF and RHF) and the frequency of the maximum phase. These RC are helpful to determine if the PEMFC with the current operating conditions is well humidified. If the zone defined by RLF decrease, RHF slight increase and the frequency of the maximum phase increase is minimal, the cathode is optimally humidified. Equivalent Circuit are used in order to give a physical interpretation. The selected parameters as performance indicators are: membrane resistance, Rm, time constant and resistance of diffusion process (using Warburg elements: Tw and Rw). In this case, the humidification of the fuel cell is optimum if the zone where Rw and Tw decrease and Rm has slow increase is minimal. Model Based performance indicators are proposed: Rm, effective diffusion coefficient, Deff and effective active area, Aeff. The optimal humidification occurs when the zone where Deff is stationary and Rm has not changed significantly, is minimal. The parameter Aeff involved in this last diagnosis procedure can be detached from the humidification interruption test and be used to estimate the effective active area and then is also helpful to compare the PEMFC performance in different operating conditions.

    Una pila de combustible es un dispositivo que da energía eléctrica a partir de reacciones electroquímicas de reducción y oxidación. Las pilas del tipo PEMFC presentan propiedades que las hacen adecuadas para aplicaciones de transporte: alta eficiencia, cero emisiones, electrolito sólido, bajas temperaturas de operación y alta densidad de potencia. Sin embargo, algunos problemas técnicos deben ser estudiados: la durabilidad de los materiales y la correcta selección de las condiciones de funcionamiento. Una de las más importantes es la gestión del agua. Un balance adecuado del agua en la pila es necesario para maximizar la eficiencia de la PEMFC reduciendo al mínimo las pérdidas de tensión. El contenido de agua en la PEMFC viene dado por su generación en el cátodo debido a la reacción, la humedad de los gases de entrada y el transporte de agua a través de la membrana. La tesis estudia, propone y compara los diferentes métodos de caracterización experimental con el objetivo de obtener indicadores del estado del agua en la PEMFC. Se realiza un uso sistemático de la técnica “espectroscopía de impedancia electroquímica (EIS)” y el análisis de la influencia de las diferentes condiciones de operación sobre la respuesta de la PEMFC. Las variables estudiadas son: corriente de carga, presión de los gases, temperatura, humedad relativa y también la alimentación de los gases de entrada: H2/O2 y H2/aire. Se presenta un conjunto de características relevantes de la respuesta del EIS y se usan para dar valores iniciales a los circuitos equivalentes. Se estudian diferentes configuraciones de circuitos equivalentes y se seleccionan aquellos que tienen la mejor conexión con los datos experimentales. Se realiza un análisis de sensibilidad de los parámetros de los circuitos equivalentes con respecto a las diferentes condiciones de operación, para encontrar aquellos que sean útiles para representar estas variaciones. Se propone una nueva técnica experimental de caracterización, basada en la interrupción de la humidificación de los gases de entrada. Esta técnica combina la información de la respuesta temporal con la frecuencial (EIS) y es útil para analizar la influencia del agua en la respuesta de la PEMFC. Algunas ventajas de esta técnica son: la fácil implementación física y el bajo impacto sobre la respuesta de la PEMFC, lo cual convierte esta técnica en candidata para ser utilizada “In-situ”. Se proponen tres conjuntos de indicadores de comportamiento de la pila como herramientas de diagnosis. En primer lugar, se presentan las “Características Relevantes” de la respuesta de la EIS que dan un diagnóstico del estado interno de la PEMFC. De entre ellas se selecciona como indicadas: las resistencias de baja y alta frecuencia (RLF y RHF) y la frecuencia del máximo de fase. Estas características sirven para determinar la correcta humidificación de la pila en las condiciones actuales de operación. El cátodo está correctamente humidificado si la respuesta de las características, muestran que la zona definida por RLF bajando, RHF subiendo ligeramente y la frecuencia de la máxima fase está subiendo, es mínima. En segundo lugar, se usan los “Circuitos Equivalentes” para dar una interpretación física a los indicadores. Los parámetros seleccionados son: la resistencia de la membrana, Rm, la resistencia y la constante de tiempo de la difusión (Rw y Tw). En este caso, la humidificación correcta del cátodo ocurre cuando la zona donde Rw y Tw bajan y Rm sube ligeramente, es mínima. Por ultimo, se proponen indicadores de comportamiento utilizando un modelo: Rm, coeficiente de difusión efectivo, Deff y el área activa efectiva, Aeff. La humidificación óptima del cátodo ocurre cuando la zona donde Deff es estable y Rm no cambia significativamente, es mínima. El parámetro Aeff es útil para estimar el área activa efectiva aun cuando no se realice una interrupción de humidificación y para comparar la respuesta de la PEMFC bajo diferentes condiciones de operacion

  • Design of optimization-based controllers applied to an ethanol steam reformer for hydrogen production

     Recio Garrido, D.; Ocampo Martinez, Carlos A.; Serra Prat, Maria
    International journal of hydrogen energy
    Vol. 37, num. 15, p. 11141-11156
    DOI: 10.1016/j.ijhydene.2012.04.117
    Date of publication: 2012-08
    Journal article

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  • Modelado, análisis y control dinámico de un reformador de etanol en tres etapas para aplicaciones en pilas de combustible  Open access

     García, Vanesa Mariel
    Institute of Industrial and Control Engineering (IOC), Universitat Politècnica de Catalunya
    Theses

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    This thesis presents results related to the design, modeling and control of a low temperature ethanol reformer as a source of hydrogen designed to feed a fuel cell (PEMFC). As fuel, ethanol has been selected as one of the renewable energy sources currently under study due to its interest for scientific and economic fields. The reformer has been separated into three stages in order to guarantee the maximum production of H2 and the minimum production of CO. SnO2 and Co(Fe)Na+/ZnO catalytic monoliths have been used, where in the first stage ethanol is dehydrogenated over SnO2 and, in the second stage, the reforming of acetaldehyde over Co(Fe)Na+/ZnO takes place under the presence of hydrogen, generated in stage 1. Then we add a third stage with a Fe2O3-Cr2O3 commercial catalyst to complete the WGS reaction. In addition to ensure a reducing environment in the reforming step, this configuration also allows optimizing the conditions of each stage of the reaction. Constant pressure has been imposed as a condition of the reformer design, but the variation of temperatures in each stage has been considered. In this thesis dynamic models have been developed for the reformer of ethanol with vapour at low temperatures described previously, the stationary and dynamic response has been analysed and controllers have been designed to meet the requirements of the system. Up until now there have only been a few works that address the design and implementation of controllers for fuel reformers, and none of these have used ethanol fuel. Some are in the area of automatic control and have been applied to tubular reformers but consider other type of fuel, not ethanol, for its alimentation In this thesis the mathematical model used to represent the state of the monolithic reformer has been presented, considered and implemented. Through a study of the stationary state one can validate the different hypothesis of assumed design and through an analysis of the parametric sensitivity the operational conditions for the reform process are discussed. This way the mathematic model of the reactor can be used to explore other alternatives for the operation of the reformer putting an emphasis on the influence of temperature in the second stage as this is a variable. Afterwards a study is made of the control of the models based on the balance of mass and linearised energy. In order to realise the control study the mathematic tools RGA, MRI and CN have been used. Through this analysis the control structures have been selected which will be most suitable for design controllers which can guarantee the requirements for the fuel cell.

  • Performance indicators for the dynamics modeling and control of PEMFC systems  Open access

     Husar, Attila Peter
    Department of Heat Engines, Universitat Politècnica de Catalunya
    Theses

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    Tesi per compendi de publicacions

    Society is gradually becoming aware that the current energy industry, based on the use of fossil fuels, is inefficient, highly polluting and has a finite supply. Within the scientific community, there are indications that hydrogen (H2) as an energy vector, obtained from renewable energy sources, can represent a viable option to mitigate the problems associated with hydrocarbon combustion. In this context, the change from the current energy industry to a new structure with a significant involvement of H2 facilitates the introduction of fuel cells as elements of energy conversion. Polymer Electrolyte Membrane Fuel Cells (PEMFC) are gaining increased attention as viable energy conversion devices for a wide range of applications from automotive, stationary to portable. In order to optimize performance, these systems require active control and thus in-depth knowledge of the system dynamics which include fluid mechanics, thermal dynamics and reaction kinetics. One of the main issues, with respect to proper control of these systems, is the understanding of the water transport mechanisms through the membrane and the liquid water distribution. The thesis is based on the publication of nine international journal articles that are divided into 4 sub-topics: Dynamic fuel cell modeling, fuel cell system control-oriented analysis, identification of parameters and performance indicators and finally, fault and failure detection and system diagnosis. In the sub-topic of Dynamic Fuel cell modeling, experimentally validated Computational Fluid Dynamics (CFD) modeling is used to relate the effects of the physical phenomena associated with fluid mechanics and thermal dynamics, that occur inside the fuel cell [Alonso, 2009][Strahl, 2011], to water distribution. However, since these CFD models cannot be directly used for control, control-oriented models [Kunusch, 2008][Kunusch, 2011] have been developed in parallel. As well, another study is done in [Serra, 2006] which includes a controllability analysis of the system for future development and application of efficient controllers. The results of the above mentioned studies are limited because either they do not incorporate an electrochemical model or the model is not experimentally validated. Moreover, these models do not take into account the voltage losses due to liquid water inside the fuel cell. Therefore, there is a need to properly relate the relevant effects of fluid mechanics and thermal dynamics, including liquid water, to the fuel cell voltage. Primarily, methodologies are needed to determine the relevant indicators associated to the effect of water on the fuel cell performance. The works published in [Husar, 2008] and [Husar, 2011] treats experimental parameter identification, mainly focused on water transport through the membrane and fuel cell voltage loss indicators respectively. The implementation of the indicators indirect measurement methodology provides an experimental way for the isolation of three main types of voltage losses in the fuel cell: activation, mass transport and ohmic losses. Additionally since these voltage loss indicators relate the fuel cell operating conditions to the fuel cell voltage, they can be utilized to calibrate and validate CFD models as well as employed in novel control strategies. On the other hand, to develop reliable systems, the controller should not only take into account performance variables during standard operation but should also be able to detect failures and take the appropriate actions. A preliminary study on failure indicators is presented in [Husar 2007] and fault detection methodologies are described in [de Lira 2011]. As a whole, the compilation of articles represented in this thesis applies a comprehensive experimental approach which describes the implementation of novel methodologies and experimental procedures to characterize and model the PEMFC and their associated systems taking into consideration control oriented goals.

    La societat s'està adonant que la indústria energètica actual, basada en l'ús de combustibles fòssils, és ineficient, molt contaminant i té un subministrament limitat. Dins de la comunitat científica, hi ha indicis que el hidrogen (H2) com vector energètic, obtingut a partir de fonts d'energia renovables, pot representar una opció viable per a mitigar els problemes associats amb la combustió d'hidrocarburs. En aquest context, el canvi de la indústria energètica actual a una nova estructura amb una important participació de el hidrogen exigeix la introducció de les piles de combustible com elements de conversió d'energia. Les piles de combustible de membrana polimèrica (PEMFC) estan tenint cada vegada més atenció com a dispositius viables de conversió d'energia per a una àmplia gamma d'aplicacions com automoció, estacionàries o portàtils. Amb la finalitat d'optimitzar el seu rendiment, les piles PEM requereixen un control actiu i per tant un coneixement profund de la dinàmica del sistema, que inclou la mecànica de fluids, la dinàmica tèrmica i la cinètica de les reaccions. Un dels temes principals relacionat amb el control adequat d'aquests sistemes és la comprensió dels mecanismes de transport d'aigua a través de la membrana i la distribució d'aigua líquida. Aquesta tesi es basa en nou articles publicats en revistes internacionals que es divideixen en 4 subtemes: la modelització dinàmica de piles de combustible, l'anàlisi orientada al control del sistema, la identificació de paràmetres i d’indicadors de funcionament i, finalment, la detecció de fallades i la diagnosi dels sistemes. En el sub-tema de la modelització dinàmica de piles PEM, la modelització basada en la Dinàmica de Fluids Computacional (CFD) amb validació experimental s'ha utilitzat per a relacionar els efectes dels fenòmens físics de la mecànica de fluids i de la dinàmica tèrmica que es produeixen dintre de la pila [Alonso, 2009] [ Strahl, 2011] amb la distribució d'aigua. No obstant això, com aquests models CFD no poden ser utilitzats directament per al control, s'han desenvolupat models orientats a control [Kunusch, 2008] [Kunusch, 2011] en paral·lel. A més, en un altre estudi [Serra, 2006] s'inclou una anàlisi de control·labilitat del sistema per al desenvolupament i aplicació futurs de controladors eficaços. Però els resultats dels estudis esmentats anteriorment són limitats, ja sigui perquè no incorporen un model electroquímic o bé perquè no han estat validats experimentalment. A més, cap dels models té en compte les pèrdues de tensió degudes a l'aigua líquida dins de la pila de combustible. Per tant, hi ha una necessitat de relacionar adequadament els efectes rellevants de la mecànica de fluids i de la dinàmica tèrmica, incloent l'aigua líquida, amb el voltatge de la pila de combustible. Principalment, són necessàries metodologies per a determinar els indicadors rellevants associats a aquest efecte de l'aigua sobre el rendiment de la pila de combustible. Els treballs publicats en [Husar, 2008] i [Husar, 2011] tracten la identificació experimental de paràmetres, centrada en el transport d'aigua a través de la membrana i els indicadors de pèrdua de tensió, respectivament. L'aplicació d'una proposta de metodologia de mesura indirecte dels indicadors permet l'aïllament dels tres tipus principals de pèrdues de voltatge en la pila de combustible: l'activació, el transport de massa i les pèrdues ohmiques. Aquests indicadors de pèrdua de tensió relacionen les condicions d'operació amb el voltatge de la pila de combustible i per tant poden ser utilitzats per a calibrar i validar models CFD, així com per a definir noves estratègies de control. D'altra banda, per a aconseguir sistemes fiables, el controlador no només ha de considerar els indicadors de funcionament de l'operació normal, sinó que també ha de detectar possibles fallades per a poder prendre les accions adequades en cas de fallada. Un estudi preliminar sobre indicadors de fallades es presenta en [Husar 2007] i una metodologia de detecció de fallades completa es descriu en [Lira de 2011]. En el seu conjunt, el compendi d'articles que formen aquesta tesi segueix un enfocament experimental i descriu la implementació de noves metodologies i procediments experimentals per a la caracterització i el modelatge de piles PEM i els sistemes associats amb objectius orientats al control eficient d'aquests sistemes.

    La sociedad se ésta dando cuenta de que la industria energética actual, basada en el uso de combustibles fósiles, es ineficiente, muy contaminante y tiene un suministro limitado. Dentro de la comunidad científica, hay indicios de que el hidrógeno (H2) como vector energético, obtenido a partir de fuentes de energía renovables, puede representar una opción viable para mitigar los problemas asociados con la combustión de hidrocarburos. En este contexto, el cambio de la industria energética actual a una nueva estructura con una importante participación de H2 exige la introducción de pilas de combustible como elementos de conversión de energía. Las pilas de combustible de membrana polimérica (PEMFC) están ganando cada vez más atención como dispositivos viables de conversión de energía para una amplia gama de aplicaciones como automoción, estacionarias o portátiles. Con el fin de optimizar su rendimiento, las pilas PEM requieren un control activo y por lo tanto un conocimiento profundo de la dinámica del sistema, que incluye la mecánica de fluidos, la dinámica térmica y la cinética de las reacciones. Uno de los temas principales relacionado con el control adecuado de estos sistemas, es la comprensión de los mecanismos de transporte de agua a través de la membrana y la distribución de agua líquida. Esta tesis se basa en la publicación de nueve artículos en revistas internacionales que se dividen en 4 sub-temas: el modelado dinámico de pilas de combustible, el análisis orientado a control del sistema, la identificación de parámetros e indicadores de desempeño y, por último, la detección de fallos y la diagnosis. En el sub-tema de la modelización dinámica de pilas PEM, el modelado basado en Dinámica de Fluidos Computacional (CFD) con validación experimental se ha utilizado para relacionar los efectos de los fenómenos físicos de la mecánica de fluidos y la dinámica térmica que se producen dentro de la pila [Alonso, 2009] [ Strahl, 2011] con la distribución de agua. Sin embargo, como estos modelos CFD no pueden ser utilizados directamente para el control, modelos orientados a control [Kunusch, 2008] [Kunusch, 2011] se han desarrollado en paralelo. Además, en otro estudio [Serra, 2006] se incluye un análisis de controlabilidad del sistema para el futuro desarrollo y aplicación de controladores eficaces. Pero los resultados de los estudios mencionados anteriormente son limitados, ya sea porque no incorporan un modelo electroquímico o bien porque no son validados experimentalmente. Además, ninguno de los modelos tiene en cuenta las pérdidas de tensión debidas al agua líquida dentro de la pila de combustible. Por lo tanto, hay una necesidad de relacionar adecuadamente los efectos relevantes de la mecánica de fluidos y la dinámica térmica, incluyendo el agua líquida, con la tensión de la pila de combustible. Principalmente, son necesarias metodologías para determinar los indicadores relevantes asociados al efecto del agua sobre el rendimiento de la pila de combustible. Los trabajos publicados en [Husar, 2008] y [Husar, 2011] tratan la identificación experimental de parámetros, centrada en el transporte de agua a través de la membrana y los indicadores de pérdida de tensió, respectivamente. La aplicación de una metodología propuesta de medición indirecta de los indicadores permite el aislamiento de los tres tipos principales de pérdidas de tensión en la pila de combustible: la activación, el transporte de masa y las pérdidas óhmicas. Éstos indicadores de pérdida de tensión relacionan las condiciones de operación con la tensión de la pila de combustible y por lo tanto pueden ser utilizados para calibrar y validar modelos CFD, así como para definir nuevas estrategias de control. Por otro lado, para conseguir sistemas fiables, el controlador no sólo debe considerar los indicadores de desempeño de la operación regular, sino que también debe detectar posibles fallos para poder tomar las acciones adecuadas en caso de fallo. Un estudio preliminar sobre indicadores de fallos se presenta en [Husar 2007] y una metodología de detección de fallos completa se describe en [Lira de 2011]. En su conjunto, el compendio de artículos que forman esta tesis sigue un enfoque experimental y describe la implementación de nuevas metodologías y procedimientos experimentales para la caracterización y el modelado de pilas PEM y los sistemas asociados con objetivos orientados al control eficiente de estos sistemas.

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    Distributed parameter model simulation tool for PEM fuel cells  Open access

     Sarmiento Carnevali, Maria Laura; Serra Prat, Maria; Batlle Arnau, Carles
    Congreso Nacional de Pilas de Combustible
    p. 1-4
    DOI: 10.1016/j.ijhydene.2013.04.015
    Presentation's date: 2012
    Presentation of work at congresses

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    In this work, a simulation tool for proton exchange membrane fuel cells (PEMFC) has been developed, based on a distributed parameter model. The tool is designed to perform studies of time and space variations in the direction of the gas channels. Results for steady-state and dynamic simulations for a single cell of one channel are presented and analyzed. Considered variables are concentrations of reactants, pressures, temperatures, humidification, membrane water content, current density, among others that have significant effects on the performance and durability of PEMFC.

    En este trabajo se ha desarrollado una herramienta de simulación para pilas de combustible tipo PEM, basada en un modelo de parámetros distribuidos. La herramienta está diseñada para realizar estudios de variaciones espaciales y temporales a lo largo de los canales de alimentación de reactantes. El trabajo muestra y analiza los resultados de simulación de una monocelda monocanal. Las variables estudiadas son las concentraciones de los reactantes, presiones, temperaturas, humidificación, contenido de agua de la membrana, corriente, entre otras que influyen significativamente sobre el rendimiento y durabilidad de las pilas PEM.

  • Diagnosis tools for PEMFC using humidification interruption tests

     Primucci, Mauricio Ariel; Serra Prat, Maria; Riera Colomer, Jordi
    Congreso Nacional de Pilas de Combustible
    Presentation's date: 2012
    Presentation of work at congresses

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    This article presents different diagnosis tools for Proton Exchange Membrane Fuel Cells based on the analysis of their dynamic evolution when the humidification of the inlet gases is interrupted. The diagnosis is aimed to know the internal state of the fuel cell with respect to the water distribution. The proposed diagnosis procedures combine the information of the time response with that extracted from Electrochemical Impedance Spectroscopy and consist in monitoring the evolution of a set of performance indicators during the humidification interruption. The article presents a study for the selection of these performance indicators, which are related to the physical phenomena inside the PEMFC, and describes the patterns that correspond to proper or improper water distribution.

  • Experimental model for a DMC-based control applied to a PEM fuel cell

     Feroldi, Diego Hernan; Allué Fantova, Miguel; Riera Colomer, Jordi; Serra Prat, Maria; Basualdo, Marta
    Mediterranean Conference on Control & Automation
    p. 854-859
    DOI: 10.1109/MED.2012.6265745
    Presentation's date: 2012
    Presentation of work at congresses

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  • Controllability study of an ethanol steam reforming process for hydrogen production

     Garcia, Vanesa Mariel; Serra Prat, Maria; Llorca, J.
    Journal of power sources
    Vol. 196, num. 9, p. 4411-4417
    DOI: 10.1016/j.jpowsour.2010.12.062
    Date of publication: 2011
    Journal article

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  • Development and experimental validation of a dynamic thermal and water distribution model of an open cathode proton exchange membrane fuel cell

     Strahl, Stephan; Husar, Attila Peter; Serra Prat, Maria
    Journal of power sources
    Vol. 196, num. 9, p. 4251-4263
    DOI: 10.1016/j.jpowsour.2010.10.074
    Date of publication: 2011
    Journal article

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  • Diseño e implementación de sistemas de control para pilas de combustible pem y su integración en sistemas distribuidos de generación

     Garcia, Vanesa Mariel; Riera Colomer, Jordi; Sarmiento Carnevali, Maria Laura; Kunusch, Cristian; Montoto Gayete, Amadeo; Creemers, Tom Lambert; Husar, Attila Peter; Serra Prat, Maria
    Competitive project

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  • Design of linear controllers applied to an ethanol steam reformer for PEM fuel cell applications

     Garcia, Vanesa Mariel; Serra Prat, Maria; Llorca, J.; Riera Colomer, Jordi
    HYdrogen ¿ POwer THeoretical and Engineering Solutions International Symposium
    Presentation's date: 2011
    Presentation of work at congresses

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    This paper focuses on the design of a controller for a low temperature ethanol steam reformer for the production of hydrogen to feed a Protonic Exchange Membrane (PEM) fuel cell. It describes different control structures for the reformer and treats the control structure selection of this Multiple Input Multiple Output (MIMO) system. For each control structure, decentralised 2x2 controllers are implemented and a Proportional Integral (PI) control action is implemented in each control loop. The PI parameters are tuned and the performance of the different linear controllers is compared though simulation. For the evaluation of the proposed controllers, the response time for different initial conditions and changes in the references is analysed, as well as the behaviour of the controlled system in front of disturbances.

  • Dynamic modeling and controllability analysis of an ethanol reformer for fuel cell application

     Garcia, Vanesa Mariel; Lopez Null, Eduardo; Serra Prat, Maria; Llorca Pique, Jordi; Riera Colomer, Jordi
    International journal of hydrogen energy
    Vol. 35, num. 18, p. 9768-9775
    DOI: 10.1016/j.ijhydene.2009.09.064
    Date of publication: 2010-09
    Journal article

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  • Control and design of PEM fuel cell-based systems: advantages of fuel cell hybrid systems with supercapacitors

     Feroldi, Diego Hernan; Riera Colomer, Jordi; Serra Prat, Maria
    Date of publication: 2010
    Book

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  • Characterization, development and experimental validation of a dynamic model of an open cathode PEM fuel cell

     Strahl, Stephan; Husar, Attila Peter; Serra Prat, Maria
    Congreso Nacional de Pilas de Combustible
    p. 1-4
    Presentation's date: 2010
    Presentation of work at congresses

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  • Estudio de controlabilidad de un proceso de reformado de etanol con vapor para la producción de hidrógeno

     Garcia, Vanesa Mariel; Serra Prat, Maria; Llorca Pique, Jordi
    Congreso Nacional de Pilas de Combustible
    p. 329-332
    Presentation's date: 2010
    Presentation of work at congresses

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    En este trabajo hemos modelado un sistema de reformado de etanol con vapor y purificación de monóxido de carbono (CO). Dicho sistema está destinado a alimentar una pila de combustible tipo PEM. A partir del modelo hemos realizado un estudio de sensibilidad y controlabilidad enfatizando la influencia de la temperatura en las variables de salida de interés. Los resultados del estudio de controlabilidad se utilizan para la selección de las estructuras de control más convenientes.

  • Linear control design of an ethanol steam reforming process for PEM fuel cell applications

     Garcia, Vanesa Mariel; Serra Prat, Maria; Llorca Pique, Jordi; Riera Colomer, Jordi
    Fuel Cells Science & Technology: Scientific Advances in Fuel Cell Systems
    p. 07-08
    Presentation's date: 2010
    Presentation of work at congresses

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    Design and analysis of fuel-cell hybrid systems oriented to automotive applications  Open access

     Feroldi, Diego Hernan; Serra Prat, Maria; Riera Colomer, Jordi
    IEEE transactions on vehicular technology
    Vol. 58, num. 9, p. 4720-4729
    DOI: 10.1109/TVT.2009.2027241
    Date of publication: 2009-11
    Journal article

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    Hybridization with high specific energy-storage devices such as supercapacitors (SCs) has important advantages in fuel-cell (FC)-based systems. This paper presents an approach for the design and analysis of FC hybrid systems (FCHSs) oriented to automotive applications. The FCHS is considered to be the most attractive long-term option for propulsion of passenger cars. The design stage includes the determination of the electrical topology and the determination of the hybridization degree (HD) according to drivability conditions. With the selected design, the optimal hydrogen consumption for different driving cycles and the energy flows in the hybrid vehicle are analyzed. The entire study is performed with a detailedmodel of the FCHS in the Advanced Vehicle Simulator (ADVISOR): the determination of the HD according to drivability requirements, the analysis of the energy flows, and the computation of the optimal hydrogen consumption. The results show that hybridization allows a significant improvement in the hydrogen economy through the recovered energy from breaking. At the same time, the results suggest a conflict between a design according to drivability conditions and a design for the highest efficiency. The conclusion is that hybridization with SCs in FC-based vehicles is a meaningful procedure that enhances performance.

  • ACES CONTROL AVANÇAT DE SISTEMES D'ENERGIA

     Serra Prat, Maria; Franch Bullich, Jaime; Costa Castelló, Ramon; Batlle Arnau, Carles; Doria Cerezo, Arnau; Griño Cubero, Roberto; Biel Sole, Domingo; Riera Colomer, Jordi; Olm Miras, Josep Maria; Sarmiento Carnevali, Maria Laura; Fossas Colet, Enric
    Competitive project

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  • Dynamic modeling of a three-stage low-temperature ethanol reformer for fuel cell application

     Garcia, Vanesa Mariel; Lopez, E; Serra Prat, Maria; Llorca Pique, Jordi
    Journal of power sources
    Vol. 192, num. 1, p. 208-215
    Date of publication: 2009-07
    Journal article

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  • Control and design of pem fuel cell-based systems.

     Feroldi, Diego Hernan
    Institute of Industrial and Control Engineering (IOC), Universitat Politècnica de Catalunya
    Theses

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  • Energy management strategies based on efficiency map for fuel cell hybrid vehicles

     Feroldi, Diego Hernan; Serra Prat, Maria; Riera Colomer, Jordi
    Journal of power sources
    Vol. 190, num. 2, p. 387-401
    Date of publication: 2009-05
    Journal article

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    Analysis of the control structures for an integrated ethanol processor for proton exchange membrane fuel cell systems  Open access

     Biset, S; Nieto Deglioumini, Lucas; Basualdo, Marta; Garcia, Vanesa Mariel; Serra Prat, Maria
    Journal of power sources
    Vol. 192, num. 1, p. 107-113
    DOI: 10.1016/j.jpowsour.2008.12.099
    Date of publication: 2009
    Journal article

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    The aim of this work is to investigate which would be a good preliminary plantwide control structure for the process of Hydrogen production from bioethanol to be used in a proton exchange membrane (PEM) accounting only steady-state information. The objective is to keep the process under optimal operation point, that is doing energy integration to achieve the maximum efficiency. Ethanol, produced from renewable feedstocks, feeds a fuel processor investigated for steam reforming, followed by high- and lowtemperature shift reactors and preferential oxidation, which are coupled to a polymeric fuel cell. Applying steady-state simulation techniques and using thermodynamic models the performance of the complete system with two different control structures have been evaluated for the most typical perturbations. A sensitivity analysis for the key process variables together with the rigorous operability requirements for the fuel cell are taking into account for defining acceptable plantwide control structure. This is the first work showing an alternative control structure applied to this kind of process.

    Postprint (author's final draft)

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    Numerical Model for Polymer Electrolyte Membrane Fuel Cells with Experimental Application and Validation  Open access

     Alonso Mora, Javier; Husar, Attila Peter; Serra Prat, Maria; Riera Colomer, Jordi
    Asia-pacific journal of chemical engineering
    Vol. 4, num. 1, p. 55-67
    DOI: 10.1002/apj.195
    Date of publication: 2009
    Journal article

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    The aim of this paper is to present a simple 3D computational model of a Polymer Electrolyte Membrane Fuel Cell (PEMFC) that simulates over time the heat distribution, energy and mass balance of the reactant gas flows in the fuel cell including pressure drop, humidity and liquid water. Although this theoretical model can be adapted to any type of PEMFC, for verification of the model and to present different analysis, it has been adapted to a single cell test fixture. The model parameters were adjusted through a series of experimental tests and the model was experimentally validated for a well defined range of operating conditions: H2/Air as reactants, flow rates of 0.5-1.5 SLPM, dew points and cell temperatures of 30-80ºC, currents 0-5 A and with/without water condensation. The model is especially suited for the analysis of liquid water condensation in the reactant channels. A key finding is that the critical current at which liquid water is formed is determined at different flows, temperatures and humidity.

    Postprint (author’s final draft)

  • Model-based fault diagnosis in PEM fuel cell systems

     Escobet Canal, Teresa; Feroldi, Diego Hernan; de Lira Ramírez, Salvador; Puig Cayuela, Vicenç; Quevedo Casin, Joseba-jokin; Riera Colomer, Jordi; Serra Prat, Maria
    Journal of power sources
    num. 192, p. 216-223
    Date of publication: 2009-01
    Journal article

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    Advances in HOSM Control Design and Implementation for PEM Fuel Cell Systems  Open access

     Kunusch, Cristian; Mayosky, Miguel Angel; Serra Prat, Maria; Puleston, Paul
    IFAC International Conference on Methods and Models in Automation and Robotics
    p. 1000-1007
    Presentation's date: 2009
    Presentation of work at congresses

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    A second order sliding mode strategy to control the air supply and oxygen stoichiometry of a fuel cell based generation system is presented. The control design is accomplished from a complete model of a experimental plant that was previously developed by the authors and specially suited for nonlinear control issues. The resulting controller endows the system with enhanced dynamic characteristics and robustness to model uncertainties and external disturbances. Simulations and experimental results are provided, showing the feasibility and reliability of the approach.

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    Energy management strategies for fuel cell-hybrid vehicles  Open access

     Feroldi, Diego Hernan; Roig Remon, Enric; Serra Prat, Maria; Riera Colomer, Jordi
    Simposium Ibérico de Hidrógeno, Pilas de Combustible y Baterías Avanzadas
    p. 1-26
    Presentation's date: 2008
    Presentation of work at congresses

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    This paper presents an analysis and a comparative study between three new proposed Energy Management Strategies oriented to Fuel Cell-Hybrid Vehicles (FCHVs). The vehicle in study is powered by a fuel cell and a supercapacitor bank that can be charged both from the fuel cell and from the load trough regenerative braking. The proposed strategies were tested using a FCHV model elaborated employing ADVISOR toolbox in Matlab. A comparative of the hydrogen consumptions is performed with respect to the optimal case, which is estimated assuming that the entire future driving load demand is known. The results indicate that it is possible to achieve a performance close to the optimal case without knowing the driving cycle a priori. In addition to the hydrogen economy improvement, the strategies allow reducing the fuel cell stack dimension with the consequent reduction in the production costs.

  • Test de interrupción de la humidificación para la diagnosis en pilas PEM

     Primucci, Mauricio Ariel; Serra Prat, Maria; Riera Colomer, Jordi
    Congreso Nacional de Pilas de Combustible
    p. 1-4
    Presentation's date: 2008
    Presentation of work at congresses

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    Uno de los principales temas de investigación relacionados con las pilas de combustible del tipo de membrana de electrolito polimérico es su fiabilidad. Además de los aspectos de seguridad, es básico hacer una diagnosis del estado interno de la pila para corregir y optimizar su funcionamiento. El estado interno de la pila de combustible cambia con las condiciones de operación, dadas por: las temperaturas, la presión, la humidificación de los gases, la concentración de reactantes y la corriente. En este trabajo se presenta la combinación de una técnica de caracterización experimental, la espectroscopía de impedancia electroquímica, y la interrupción de la humidificación de los gases reactantes para determinar el estado interno de la pila. La realización de varias espectroscopias mientras se desarrolla el transitorio de interrupción de la humidificación permite obtener la evolución de ciertas características relevantes que pueden ser utilizadas en el diagnóstico del estado de la pila.

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    Characterisation of fuel cell state using Electrochemical Impedance Spectroscopy analysis  Open access

     Primucci, Mauricio Ariel; Ferrer Bonada, Lluís; Serra Prat, Maria; Riera Colomer, Jordi
    Simposium Ibérico de Hidrógeno, Pilas de Combustible y Baterías Avanzadas
    p. 1-26
    Presentation's date: 2008
    Presentation of work at congresses

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  • Análisis de estructuras de control para una planta de generación de H2 para pila de combustible

     Biset, S; Basualdo, Marta; Garcia, Vanesa Mariel; Serra Prat, Maria
    Congreso Nacional de Pilas de Combustible
    p. 395-398
    Presentation's date: 2008
    Presentation of work at congresses

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    El sistema estudiado en este trabajo está compuesto por un conjunto de reactores que procesan etanol para obtener el H2 que reacciona con el oxígeno del aire en una celda de combustible. Estos dispositivos se emplean para la generación de potencia eléctrica a partir de energía química almacenada ya que presentan alta eficiencia térmica, bajas emisiones de CO2 y son dispositivos generalmente portables. El estudio se realiza sobre la planta simulada en estado estacionario mediante el uso del software HYSYS. Disponiendo de las condiciones operativas del proceso que optimizan el consumo energético se evalúan diferentes estructuras de control. Preliminarmente este análisis se realiza sobre las variables claves del proceso y la decisión sobre cuál es la mejor estructura se basa en un estudio de sensitividad a perturbaciones típicas del sistema.

  • Experimental methodology for modeling water diffusion transport in a PEMFC stack with respect to membrane temperature and resistance

     Husar, Attila Peter; Serra Prat, Maria; Riera Colomer, Jordi
    Fuel Cells Science & Technology: Scientific Advances in Fuel Cell Systems
    p. 5-
    Presentation's date: 2008
    Presentation of work at congresses

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  • Modeling of a three-stage low temperature ethanol steam reforming reactor for fuel cell applications.

     Garcia, Vanesa Mariel; Llorca Pique, Jordi; Serra Prat, Maria; Riera, J.
    Fuel Cell Science and Technology 2008. Scientific Advances in Fuel Cells Systems
    p. 1-77
    Presentation of work at congresses

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  • Modelo dinámico de un reformador de etanol a bajas temperaturas para la alimentación de pilas de combustible

     Garcia, Vanesa Mariel; López, Eduardo; Serra Prat, Maria; Llorca Pique, Jordi
    III Congreso Nacional de Pilas de Combustible
    p. 1-5
    Presentation of work at congresses

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  • Performance improvement of a PEMFC system controlling the cathode outlet air flow

     Feroldi, D; Serra Prat, Maria; Riera Colomer, Jordi
    Journal of power sources
    Vol. 169, num. 1, p. 205-212
    Date of publication: 2007-06
    Journal article

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  • Description of gasket failure in a 7-cell PEMFC stack

     Serra Prat, Maria
    Journal of power sources
    Vol. 169, num. 2, p. 85-91
    Date of publication: 2007-06
    Journal article

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    Performance improvement of a PEMFC system controlling the cathode outlet air flow  Open access

     Feroldi, Diego Hernan; Serra Prat, Maria; Riera Colomer, Jordi
    Journal of power sources
    Vol. 169, num. 1, p. 205-212
    Date of publication: 2007-01
    Journal article

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    This paper presents a stationary and dynamic study of the advantages of using a regulating valve for the cathode outlet flow in combination with the compressor motor voltage as manipulated variables in a fuel cell system. At a given load current, the cathode input and output flowrate determine the cathode pressure and stoichiometry, and consequently determine the oxygen partial pressure, the generated voltage and the compressor power consumption. In order to maintain a high efficiency during operation, the cathode output regulating valve has to be adjusted to the operating conditions, specially marked by the current drawn from the stack. Besides, the appropriate valve manipulation produces an improvement in the transient response of the system. The influence of this input variable is exploited by implementing a predictive control strategy based on dynamic matrix control (DMC), using the compressor voltage and the cathode output regulating valve as manipulated variables. The objectives of this control strategy are to regulate both the fuel cell voltage and oxygen excess ratio in the cathode, and thus, to improve the system performance. All the simulation results have been obtained using the MATLAB-Simulink environment.

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    Description of gasket failure in a 7 cell PEMFC stack  Open access

     Husar, Attila Peter; Serra Prat, Maria; Kunusch, Cristian
    Journal of power sources
    Vol. 169, num. 1, p. ; serr-
    Date of publication: 2007-01
    Journal article

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    This article presents the data and the description of a fuel cell stack that failed due to gasket degradation. The fuel cell under study is a 7 cell stack. The unexpected change in several variables such as temperature, pressure and voltage indicated the possible failure of the stack. The stack was monitored over a 6 h period in which data was collected and consequently analyzed to conclude that the fuel cell stack failed due to a crossover leak on the anode inlet port located on the cathode side gasket of cell #2. This stack failure analysis revealed a series of indicators that could be used by a supervisional controller in order to initiate a shutdown procedure.

  • Control de la respuesta dinámica de la tensión generada y del suministro de energía en sistemas basados en pilas de combustible PEM

     Serra Prat, Maria
    II Congreso Nacional de Pilas de Combustible
    Presentation's date: 2006-10-18
    Presentation of work at congresses

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  • Descripción del fallo en el sellado de una pila PEM de 7 celdas

     Serra Prat, Maria
    II Congreso Nacional de Pilas de Combustible
    Presentation's date: 2006-10-18
    Presentation of work at congresses

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  • Control multivariable de una pila de combustible tipo PEM mediante control predictivo de matriz dinámica

     Serra Prat, Maria
    II Jornadas Iberoamericanas de Pilas de Combustible e Hidrógeno
    Presentation's date: 2006-07-24
    Presentation of work at congresses

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