Enhancing fuel cell lifetime performance through effective health management

Hydrogen fuel cells, and notably the polymer electrolyte fuel cell (PEFC), present an important opportunity to reduce greenhouse gas emissions within a range of sectors of society, particularly for transportation and portable products. Despite several decades of research and development, there exist three main hurdles to full commercialisation; namely infrastructure, costs, and durability. This thesis considers the latter of these. The lifetime target for an automotive fuel cell power plant is to survive 5000 hours of usage before significant performance loss; current demonstration projects have only accomplished half of this target, often due to PEFC stack component degradation. Health management techniques have been identified as an opportunity to overcome the durability limitations. By monitoring the PEFC for faulty operation, it is hoped that control actions can be made to restore or maintain performance, and achieve the desired lifetime durability. This thesis presents fault detection and diagnosis approaches with the goal of isolating a range of component degradation modes from within the PEFC construction. Fault detection is achieved through residual analysis against an electrochemical model of healthy stack condition. An expert knowledge-based diagnostic approach is developed for fault isolation. This analysis is enabled through fuzzy logic calculations, which allows for computational reasoning against linguistic terminology and expert understanding of degradation phenomena. An experimental test bench has been utilised to test the health management processes, and demonstrate functionality. Through different steady-state and dynamic loading conditions, including a simulation of automotive application, diagnosis results can be observed for PEFC degradation cases. This research contributes to the areas of reliability analysis and health management of PEFC fuel cells. Established PEFC models have been updated to represent more accurately an application PEFC. The fuzzy logic knowledge-based diagnostic is the greatest novel contribution, with no examples of this application in the literature

Performance indicators for the dynamics modeling and control of PEMFC systems

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

Advancements in Polymer Electrolyte Fuel Cell Architecture and Performance using Electrochemical Modelling and Advanced Characterisations

With the ever depleting traditional energy sources and increasing the carbon footprints, the new landscape of the renewable energy sources has evolved. With the versatility of required environmental conditions, topological locations, operating temperature, polymer electrolyte fuel cells (PEFCs) operating on hydrogen has been recognised as a prominent renewable energy technology. PEFCs offers the possibility of zero-emission and high power density electricity generation for a wide range of transport, portable, and stationary power applications. While technology continues to improve, there are still some challenges concerning durability, cost and performance. An improved understanding of the processes occurring within operational fuel cells and optimisation of the cell architecture will accelerate large-scale commercialization of PEFCs. The most powerful ways to understand and resolve these challenges is to understand the complex interplay of the internal workings of fuel cells and cell design and architecture and operating conditions. Hence, the current research aims to analyse the advancements in the fuel cell design and architecture using a thermo-structural multiphase electrochemical modelling and the advanced characterisation techniques Firstly, the intricate relationship between cell compression and the flow-field architecture is established by determining the morphological factors using X-ray computed tomography (CT) techniques. The results provide insight into the complex interplay of the morphological factors deciding fuel cell performance and durability. Also, this study provides insight into the extent at which the morphological factors decide water and thermal management of the fuel cell, which are key issues to tackle to broad-scale commercialisation of the technology. Further, the multiphase non-isothermal two-dimensional numerical model was developed. The two-dimensional current, temperature and liquid water saturation profiles reveal the in-situ gradients and their correlations with the voltage decay with respect to an increase in cell compression. Finally, the effects of cell compression on the PEFC water dynamics were analysed using in-plane and through-plane in-operando neutron radiography. Neutron radiography provides a detailed understanding of what constitutes the thickness of liquid water present in the operating fuel cell. The Neutron radiography results were also used to validate the numerical models developed. Finally, this work also investigates the effect of secondary flow-field on the dead-ended anode performance and highlights the importance of the manufacturing and assembly tolerances on fuel cell efficiency. Collectively; this project delineates the comprehensive suite of characterisation techniques and numerical modelling to resolve the PEFC challenges and achieve the cell optimisation and durability required for wide-scale commercialisation of the technology

Proton Exchange Membrane Fuel Cells (PEMFCs)

The proton exchange membrane fuel cell is an electrochemical energy conversion device, which transforms a fuel such as hydrogen and an oxidant such as oxygen in ambient air into electricity with heat and water byproducts. The device is more efficient than an internal combustion engine because reactants are directly converted into energy through a one-step electrochemical reaction. Fuel cells combined with water electrolyzers, which electrochemically split water into hydrogen and oxygen using renewable energy sources such as solar, mitigate global warming concerns with reduced carbon dioxide emissions. This collection of papers covers recent advancements in fuel cell technology aimed at reducing cost, improving performance, and extending durability, which are perceived as crucial for a successful commercialization. Almost all key materials, as well as their integration into a cell, are discussed: the bus plates that collect the electrical current, the gas diffusion medium that distributes the reactants over catalysts promoting faster reactions, and the membrane separating oxygen and hydrogen gases and closing the electrical circuit by transporting protons. Fuel cell operation below the freezing point of water and with impure reactant streams, which impacts durability, is also discussed

FC³ - 1st Fuel Cell Conference Chemnitz 2019 - Saubere Antriebe. Effizient Produziert.: Wissenschaftliche Beiträge und Präsentationen der ersten Brennstoffzellenkonferenz am 26. und 27. November 2019 in Chemnitz

Die erste Chemnitzer Brennstoffzellenkonferenz wurde vom Innovationscluster HZwo und dem Fraunhofer-Institut für Werkzeugmaschinen und Umformtechnik IWU durchgeführt. Ausgewählte Fachbeiträge und Präsentationen werden in Form eines Tagungsbandes veröffentlicht.The first fuel cell conference was initiated by the innovation cluster HZwo and the Fraunhofer Institute for Machine Tools and Forming Technology. Selected lectures and presentations are published in the conference proceedings

Multivariate characterisation of dual-layered catalysts, reliability and durability of Polymer Electrolyte Membrane Fuel Cells

Hydrogen fuel cells have held out the promise of clean, sustainable power generation for decades, but have failed to deliver on that potential. Inefficiencies in research and development work can be overcome to increase the rate of new knowledge acquisition in this field. A number of medical and engineering disciplines utilise a wide variety of statistical tools in their research to achieve this same end, but there has been little adoption of such statistical approaches within the fuel cell research community. This research undertakes a design of experiments (DoE) approach to the analysis of multiply-covarying (M-ANOVAR) factors by using historic data, and direct experimental work, on a wide variety of polymer electrolyte membrane fuel cells (PEMFCs) cathode gas diffusion media (GDM) and dual layered catalyst structures. This research developed a gradient of polarisation regions' approach; a method for making robust numerical comparisons between large numbers of samples based on polarisation curves, while still measuring the more usual peak power of the PEMFC. The assessment of polarisation gradients was completed in a statistically robust fashion that enabled the creation of regression models of GDMs for multiple input and multiple output data sets. Having established the multivariate method; a set of possibly co-varying factors, a DoE approach was used to assess GDM selection, dual layered catalyst structures and degradation of membrane electrode assembly (MEA) performance over time. Degradation studies monopolise resources to be monopolised for protracted periods. M-ANOVAR allows the addition of other factors in the study, and the total efficiency of the degradation experiment is increased. A 20% reduction in the number of samples to be tested was achieved in the case study presented in this thesis (compared to the usual one factor at a time (OFAT) approach). This research highlights the flexibility and efficiency of DoE approaches to PEMFC degradation experimentation. This research is unique in that it creates catalyst ink formulations where the variation in catalyst loading in each sub-layer of the catalyst layer (CL) was achieved by having a different concentration of the catalyst material on the carbon supports. The final M-ANOVAR analysis indicates a simple average of the individual responses was appropriate for the experiments undertaken. It was shown that low concentration dual layer catalysts on paper GDMs have improved performance compared to paper GDMs with uniform, single layer catalysts: Demonstrating reduced platinum concentrations to achieve equivalent open cell performance. The time to peak power during testing (how long after starting the test it takes to achieve the maximum performance in the cell) was strongly impacted by GDM selection. Furthermore, there was a strong suggestion that previously published results crediting a change in performance due to a single layer, or multi-layered catalyst structures may, in fact, have been due to the selection of GDM used in the experiment instead

Pem fuel cell modeling and converters design for a 48 v dc power bus

Fuel cells (FC) are electrochemical devices that directly convert the chemical energy of a fuel into electricity. Power systems based on proton exchange membrane fuel cell (PEMFC) technology have been the object of increasing attention in recent years as they appear very promising in both stationary and mobile applications due to their high efficiency, low operating temperature allowing fast startup, high power density, solid electrolyte, long cell and stack life, low corrosion, excellent dynamic response with respect to the other FCs, and nonpolluting emissions to the environment if the hydrogen is obtained from renewable sources. The output-voltage characteristic in a PEMFC is limited by the mechanical devices which are used for regulating the air flow in its cathode, the hydrogen flow in its anode, its inner temperature, and the humidity of the air supplied to it. Usually, the FC time constants are dominated by the fuel delivery system, in particular by the slow dynamics of the compressor responsible for supplying the oxygen. As a consequence, a fast load transient demand could cause a high voltage drop in a short time known as oxygen starvation phenomenon that is harmful for the FC. Thus, FCs are considered as a slow dynamic response equipment with respect to the load transient requirements. Therefore, batteries, ultracapacitors or other auxiliary power sources are needed to support the operation of the FC in order to ensure a fast response to any load power transient. The resulting systems, known as FC hybrid systems, can limit the slope of the current or the power generated by the FC with the use of current-controlled dc-dc converters. In this way, the reactant gas starvation phenomena can be avoided and the system can operate with higher efficiency. The purpose of this thesis is the design of a DC-DC converter suitable to interconnect all the different elements in a PEMFC-hybrid 48-V DC bus. Since the converter could be placed between elements with very different voltage levels, a buck-boost structure has been selected. Especially to fulfill the low ripple requirements of the PEMFCs, but also those of the auxiliary storage elements and loads, our structure has inductors in series at both its input and its output. Magnetically coupling these inductors and adding a damping network to its intermediate capacitor we have designed an easily controllable converter with second-order-buck-like dominant dynamics. This new proposed topology has high efficiency and wide bandwidth acting either as a voltage or as a current regulator. The magnetic coupling allows to control with similar performances the input or the output inductor currents. This characteristic is very useful because the designed current-controlled converter is able to withstand shortcircuits at its output and, when connected to the FC, it facilitates to regulate the current extracted from the FC to avoid the oxygen starvation phenomenon. Testing in a safe way the converter connected to the FC required to build an FC simulator that was subsequently improved by developing an emulator that offered real-time processing and oxygen-starvation indication. To study the developed converters and emulators with different brands of PEMFCs it was necessary to reactivate long-time inactive Palcan FCs. Since the results provided by the manual reactivation procedure were unsatisfactory, an automatic reactivation system has been developed as a complementary study of the thesis.En esta tesis se avanzo en el diseño de un bus DC de 48 V que utiliza como elemento principal de generación de energía eléctrica una pila de combustible. Debido a que la dinámica de las pilas de combustible están limitadas por sus elementos mecánicos auxiliares de control una variación rápida de una carga conectada a ella puede ocasionar daños. Es por esto que es necesario utilizar elementos almacenadores de energía que puedan suministrar estas rápidas variaciones de carga y convertidores para que gestionen de una forma controlada la potencia del bus DC. Durante la realización de pruebas de los convertidores es de gran importancia utilizar emuladores o simuladores de pilas de combustibles, esto nos permite de una forma económica y segura realizar pruebas criticas antes de conectar los convertidores a la pila. Adicionalmente una nueva topologia de convertidor fue presentada y ésta gestionará la potencia en el bu

Advanced Modeling and Research in Hybrid Microgrid Control and Optimization

This book presents the latest solutions in fuel cell (FC) and renewable energy implementation in mobile and stationary applications. The implementation of advanced energy management and optimization strategies are detailed for fuel cell and renewable microgrids, and for the multi-FC stack architecture of FC/electric vehicles to enhance the reliability of these systems and to reduce the costs related to energy production and maintenance. Cyber-security methods based on blockchain technology to increase the resilience of FC renewable hybrid microgrids are also presented. Therefore, this book is for all readers interested in these challenging directions of research

Modeling, Parameter Identification, and Degradation-Conscious Control of Polymer Electrolyte Membrane (PEM) Fuel Cells

Polymer electrolyte membrane (PEM) fuel cells are touted as zero-emission alternatives to internal combustion engines for automotive applications. However, high cost and durability issues have hindered their commercialization. Therefore, significant research efforts are underway to better understand the scientific aspects of PEM fuel cell operation and engineer its components for improved lifetime and reduced cost. Most of the research in this area has been focused on material development. However, as demonstrated by Toyota's fuel cell vehicle, intelligent control strategies may lead to significantly improved durability of the fuel cell stack even with existing materials. Therefore, it seems that the outstanding issues can be better resolved through a combination of improved materials and effective control strategies. Accordingly, this dissertation aims to develop a model-based control strategy to improve performance and durability of PEM fuel cell systems for automotive applications. To this end, the dissertation first develops a physics-based and computationally efficient model for online estimation purposes. The need for such a model arises from the fact that detailed information about the internal states of the cell is required to develop effective control strategies for improved performance and durability, and such information is rarely available from direct measurements. Therefore, a software sensor must be developed to provide the required signals for a control system. To this end, this work utilizes spatio-temporal decoupling of the underlying problem to develop a model that can estimate water and temperature distributions throughout an operating fuel cell in a computationally efficient manner. The model is shown to capture a variety of complex physical phenomena, while running at least an order of magnitude faster than real time for dynamically changing conditions. The model is also validated with extensive experimental measurements under different operating conditions that are of interest for automotive applications. Furthermore, the dissertation extensively explores the sensitivity of the model predictions to a variety of parameters. The sensitivity results are used to study the parameter identifiability problem in detail. The challenges associated with parameter identification in such a large-scale physics-based model are highlighted and a model parameterization framework is proposed to address them. The proposed framework consists of three main components: (1) selecting a subset of model parameters for identification, (2) optimally designing experiments that are maximally informative for parameter identification, and (3) designing a multi-step identification algorithm that ensures sufficient regularization of the inverse problem. These considerations are shown to lead to effective model parameterization with limited experimental measurements. Finally, the dissertation uses a version of the proposed model to develop a degradation-conscious model-predictive control (MPC) framework to enhance the performance and durability of PEM fuel cell systems. In particular, a reduced-order model is developed for control design, which is then successively linearized about the current operating point to enable use of linear control design techniques that offer significant computational advantages. A variety of constraints on system safety and durability are considered and simulation case studies are conducted to evaluate the framework's utility in maximizing performance while respecting the durability constraints. It is also shown that the linear MPC framework employed here can generate the optimal control commands faster than real time. Therefore, the proposed framework is expected to be implementable in practical applications and contribute to extending the lifetime of fuel cell systems.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/155288/1/goshtasb_1.pd