Solid Oxide Fuel Cell Modeling

This paper discusses the modeling of a solid oxide fuel cell using both lumped and distributed modeling approaches. In particular, the focus of this paper is on the development of a computationally efficient lumped-parameter model for real-time emulation and control. The performance of this model is compared with a detailed distributed model and experimental results. The fundamental relations that govern a fuel cell operation are utilized in both approaches. However, the partial pressure of the species (fuel, air, and water) in the distributed model is assumed to vary through the length of the fuel cell. The lumped model approach uses the partial pressure of the species at the exit point of the fuel cell. The partial pressure of the species is represented by an equivalent RC circuit in the lumped model

Overview of the optimal smart energy coordination for microgrid applications

This paper describes an overview of the optimal energy coordination/management approaches for microgrids. The article presents the smart grid environment in conjunction with their technologies into the applications of a microgrid when the energy coordination aims to create power flow stability between the generation and consumption of the electricity. This energy equilibrium is made regardless of a power grid complexity that can contain diverse load demands and distributed energy resources (DERs), including renewable energy system (RES), energy storage system (ESS), electric vehicle (EV), etc. A microgrid often contains an energy mix system that requires three control levels, namely primary, secondary and tertiary, to optimize the energy cost and behavior of the system operation and exploitation. Based on several DERs, a microgrid can operate in island mode or be connected to the main grid. The energy coordination for both features is to deal with the energy resources uncertainty, the climate impact, to reduce atmospheric pollution deriving from the conventional power grid, and the energy demand growth. Through the smart grid technology, the optimization approaches of this coordination have brought several improvements into the electrical system. Thus, an overview of an intelligent energy management system for microgrid applications is intensively detailed to structure the implementation strategies which aim to coordinate the energy flow of an electrical system optimally

Optimisation and Operation of Residential Micro Combined Heat and Power (μCHP) Systems

In response to growing concerns regarding global warming and climate change, reduction of CO2 emissions becomes a priority for many countries, especially the developed ones such as the UK. Residential applications are considered among the most important areas for substantial reduction of CO2 emissions because they represent a major part of the total consumed energy in those countries. For instance, in the UK, residential applications are currently accountable for about 150 Mt CO2 emissions, which represents approximately 25% of the whole CO2 emissions [1-2]. In order to achieve a significant CO2 reduction, many strategies must be adopted in the policy of these countries. One of these strategies is to introduce micro combined heat and power (μCHP) systems into residential energy systems, since they offer several advantages over traditional systems. A significant amount of research has been carried out in this field; however, in terms of integrating such systems into residential energy systems, significant work is yet to be conducted. This is because of the complexity of these systems and their interdependency on many uncertain variables, energy demand of a house is a case in point. In order to achieve such integration, this research focuses on the optimisation and operation of μCHP systems in residential energy systems as essential steps towards integration of these systems, so it deals with the optimisation and operation of a μCHP system within a building taking into account that the system is grid-connected in order to export or import electricity in certain cases. A comprehensive review that summarises key points that outline the trend of previous research in this field has been carried out. The reviewed areas include: technologies used as residential μCHP units, modelling of the μCHP systems, sizing of μCHP systems and operation strategies used for such systems. To further this, a generic model for sizing of μCHP system’s components to meet different residential application has been developed by the author. Two different online operation strategies of residential μCHP systems, namely: an online linear programming optimiser (LPO) and a real time fuzzy logic operation strategy (FLOS) have been developed. The performance of the novel online operation strategies, in terms of their ability to reduce operation costs, has been evaluated. Both the LPO and the FLOS were found to have their advantages when compared with the traditional operation strategies of μCHP systems in terms of operation costs and CO2 emissions. This research should therefore be useful in informing design and operation decisions during developing and implementing μCHP technologies in residential applications, especially single dwellings

A Review of physics-based and data-driven models for real-time control of polymer electrolyte membrane fuel cells

The real-time model-based control of polymer electrolyte membrane (PEM) fuel cells requires a computationally efficient and sufficiently accurate model to predict the transient and long-term performance under various operational conditions, involving the pressure, temperature, humidity, and stoichiometry ratio. In this article, recent progress on the development of PEM fuel cell models that can be used for real-time control is reviewed. The major operational principles of PEM fuel cells and the associated mathematical description of the transport and electrochemical phenomena are described. The reduced-dimensional physics-based models (pseudo-two-dimensional, one-dimensional numerical and zero dimensional analytical models) and the non-physics-based models (zero-dimensional empirical and data-driven models) have been systematically examined, and the comparison of these models has been performed. It is found that the current trends for the real-time control models are (i) to couple the single cell model with balance of plants to investigate the system performance, (ii) to incorporate aging effects to enable long-term performance prediction, (iii) to increase the computational speed (especially for one-dimensional numerical models), and (iv) to develop data-driven models with artificial intelligence/machine learning algorithms. This review will be beneficial for the development of physics or non-physics based models with sufficient accuracy and computational speed to ensure the real-time control of PEM fuel cells.Toyota Motor Engineering & Manufacturing North America || Natural Sciences and Engineering Research Council of Canad

Development of neuro-fuzzy strategies for prediction and management of hybrid PV-PEMFC-battery systems.

Doctor of Philosophy in Electrical Engineering. University of KwaZulu-Natal, Durban 2017.Abstract available in PDF file

Further development of a fuel cell - electrolyser test bed and developing a microcontroller-based control system for it

Mobiililaitteiden energiankulutus kasvaa samalla kun niiden koko pienenee ja olemme lähestymässä pistettä, jossa perinteisten akkujen suorituskyky ei enää riitä. Näin ollen tarvitaan uudenlainen tehonlähde, joka tarjoaa pidemmän mobiilin käyttöajan. Tämä on tavoite IPPES projektissa, johon tämä työ sisältyy. Tässä työssä kehitettiin mobiilia käyttöaikaa pidentävä järjestelmä perustuen passiiviseen 1.5 watin PEM polttokenno -elektrolyyserijärjestelmään. Järjestelmä on hybridi, sillä siihen kuuluu myös akku ja superkondensaattori. Kehitetty järjestelmä on ainutlaatuinen, sillä järjestelmää jossa käytetään vetypolttokennoa metanolielektrolyyserin kanssa ei löytynyt kirjallisuudesta. Ohjausjärjestelmä kehitettiin LabVIEW-ohjelmiston avulla hyödyntäen tietoa edellisen IPPES-prototyypin heikkouksista ja vahvuuksista. Ohjausjärjestelmä kykeni järjestelmän automaattiseen käynnistämiseen, mobiililaitteen käyttöajan pidentämiseen ja hallittuun järjestelmän alasajoon. Samaa ohjausjärjestelmää voisi myös käyttää suurempitehoisen polttokenno -elektrolyyserijärjestelmän ohjausjärjestelmänä.As the energy consumption of mobile devices is increasing and their size is decreasing there is a need for a new type of power supply that gives a longer mobile usage time than traditional batteries. To achieve this goal, which is the goal of the IPPES project that this work is a part of, a mobile usage time extender system based on a passive hybrid 1.5 W PEM fuel cell -electrolyser system has been developed. The system also involves a rechargeable battery and a supercapacitor. The system is unique as no system using a methanol electrolyser together with a hydrogen fuel cell was found in literature. A control system was developed in LabVIEW on basis of the previous IPPES-prototype after analysing the strengths and weaknesses. Though simple, the control system was able to complete controlled start-up, mobile time extension duties for a mobile phone, and safe shutdown of the system. The same control system could be also used together with higher power fuel cells and electrolysers with only minor changes to parameters

Advanced power converters for railway traction systems

This thesis presents a new traction drive suitable for fuel-cell powered light rail vehicles based on a multilevel cascade converter with full-bridge cells. The converter provides dc-ac power conversion in a single stage, while compensating for the variation of fuel cell terminal voltage with load power. The proposed converter can replace the conventional combination of dc-dc converter, as it benefits from having a multilevel ac voltage waveform and much smaller power inductors, compared to conventional solutions. The converter numerical and analytical models are derived showing that the converter can be modelled as a cascaded boost converter and 3-phase inverter. The design methodology for the energy storage capacitors and power inductors is presented, showing that inductance is reduced at a quadratic rate with the addition of more sub-modules, while total converter capacitance remains constant. A simulation of a full-scale traction drive in a fuel cell tram demonstrates that the proposed converter is a viable solution for light rail applications. The concept of a boost modular cascaded converter is fully validated through a bespoke laboratory prototype driving a small induction machine. The experimental inverter achieves operation from standstill, with full motor torque, to field weakening with constant power, boosting a 50V dc supply to 200V peak line-to-line voltage