In this study, an Intermediate Temperature Solid Oxide Fuel Cell stack (IT-SOFC) was tested at different operating temperatures, in order to model its performance. A macroscopic quasistatic model describing the stack behavior under given operating conditions is proposed. This model is based on physical laws in order to be as generic as possible. Experimental characterizations such as polarization curves and electrochemical impedance spectroscopy are used to identify the model parameters. Four polarization curves were performed at atmospheric pressure, with pure H2 on the anode side and air on the cathode side, without any humidification. A multi-curves/multi-operating conditions parametric identification approach was used to determine a set of parameters describing all the polarization curves. The model thus proposed is capable to reproduce the stack experimental behavior, and also gives the distribution of the different electrochemical losses as a function of temperature and current density.

Le projet GENHYO (GENération HYdrogène Occitanie) a pour objectif de favoriser l’émergence de talents et d’accélérer l’adaptation des formations (du CAP au Doctorat) aux besoins en compétences de la filière de l’hydrogène décarboné. Partenaire du projet, Toulouse INP (Institut National Polytechnique) mobilise l’expertise acquise au travers des activités de recherche conduites sur la « Plateforme Hydrogène de Toulouse » opérée par le laboratoire LAPLACE (une plateforme d’expérimentation dédiée à l’étude des technologies de production, de stockage et d’utilisation de l’hydrogène) pour développer et concevoir des bancs pédagogiques qui seront installés au sein du futur Technocampus Hydrogène Occitanie situé près de Toulouse et qui s’intégreront à terme dans différents parcours de formation.

This work presents a simple power converter, without any high voltage transformer, able to supply and control a plasma jet based on dielectric barrier discharge. The converter, operating in pulsed current mode, requires a single power switch and is fed by a low voltage DC source. It can deliver very short duration pulses to the plasma jet with high current amplitude. The operating principle is explained by means of the state plane analysis and is validated with simulations and experimental results. The equations provided allow for the calculation during the design stage of important characteristics of the plasma jet as the peak voltage and the duration of the pulses. The power can be easily adjusted during experimentation to comply with the desired appearance of the plasma jet.

In order to achieve the goal of reducing the environmental footprint of the transport sector, new low-carbon energy systems including fuel cells and power converters are proposed. The sizing and operation of such systems have to take into account the aging of the fuel cell. This paper focuses on the study of a potential impact of high frequency current ripples (HFCR) on the degradation of a high-temperature proton exchange membrane fuel cell (HT-PEMFC). A 2600 h long endurance test was carried out on 4 HT-PEMFC single cells with and without HFCR. The degradation of two cells operated with a triangular current waveform of frequency 20 kHz and amplitude 20 %pp of the mean current density (0.2 A/cm2) is compared to the degradation of two cells operated at the same constant mean current density. In addition to endurance phase, several characterization phases (polarization curves, electrochemical impedance spectroscopy and cyclic voltammetry) are used to analyse the impact of the current harmonics. The obtained results show that the high frequency current ripples do not seem to accelerate the degradation of the HT-PEMFC single cells.& COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

In this study, an endurance test of 3000 h was conducted on four equivalent proton exchange membrane (PEM) electrolyzers to identify and quantify the impact of an electric ripple current on their durability. Three different typical power converter waveforms and frequencies were explored. Signals were added to the same direct current carrier and also tested for reference. Performance comparison based on polarization curves and electrochemical impedance spectroscopy (EIS) analysis revealed that the ripple current favors degradation. Triangular waveform and a frequency of 10 kHz were identified as the most degrading conditions, leading to a sharp increase in high-frequency resistance (HFR) and the emergence of mass transport limitations due to the enhanced degradation of titanium mesh. Moreover, reversible losses were observed and further explorations are needed to decorrelate them from our observations.

This article presents an experimental study of a DBD-driven plasma jet system. The aim of the study is to design a whole system (the jet reactor, its electrical power supply, and a gas-feeding apparatus) suitable for biomedical applications. The article describes the test bench developed for this purpose and discusses the parameters it controls. The measurements show that the studied solutions can be used to control critical parameters such as the jet temperature and dimensions. The best results were obtained for a bipolar short-pulse voltage power supply in the 10–20 kHz frequency range and for a series resonant inverter current power supply operated in “burst mode”, allowing low-frequency modulation.

A scale electro-thermal model has been developed for LiFePO4/graphite lithium-ion battery. Such model is appropriate in order to develop a physical emulation of a battery in the context of a hardware in the loop process, especially for testing energy management strategies of microgrids under the same conditions (solar irradiation for PV arrays, wind speed for wind turbine, state of health for storage device) and potentially by compressing testing time. Classically, physical emulation allows achieving laboratory size-scaled analysis but one major originality of the proposed approach deals with the "time-compressed experimental analysis". The electrothermal model is based on the extended modified shepherd model coupled with a 1D thermal model. The model parameters are estimated through a sequential characterization approach from several input profiles such as the hybrid pulse power characterization protocol and the open circuit voltage measurement. Both the dimensional analysis and the Vaschy-Buckingham theorem are used to obtain the scaling factors (voltage, current, "but also" time) which are applied on the original model parameters. The accuracy of the scale electrothermal model is validated on a robustness analysis (the battery current profile is based on a specific energy management strategy for a typical microgrid application) with voltage, current and time scaling. The simulation results presented in the paper show that the reduction of the time horizon of experimental tests for HIL process is possible by means of an appropriate dimensional analysis (scaling) on the model parameters.

Treatment of NOx pollutants in the gas outlet of various industrial processes, by mean of non-thermal plasma has been studied in several past works and has exhibited interesting prospects. Reactor design and plasma/catalyst mixed systems have been recently the main directions investigated for performances improvement. Nevertheless, improvements in electrical energy injection control by means of the power supply are still required to achieve efficient practical applications. In order to carry parametric investigations, concerning different DBD reactors and power supplies, an automated test-bench has been set-up and is presented: it comprises a control apparatus for inlet gas mixture and flow, a real time measurement module for all electrical variables and for gas analysis, a data acquisition interface and a fully controlled power supply, delivering square current pulses. This square current source can control the electrical power of the DBD by means of three degrees of freedom (frequency, amplitude and duration of the current pulses), and the system is used to perform automatic sweeps of these electric variables, saving the results of each experiment. Details about the operating principle of the power supply and its design are going to be presented as well as test bench experimental results and NOx destruction performances.

This article deals power hardware in the loop (PHIL) real-time simulation (also called emulation) of electric power conversion systems, especially the ones involving battery storage. A case study related to a wind turbine power conversion system hybridized with a lithium-ion battery illustrates the main concepts. A similitude reduction process is presented to scale the model parameters in order to fulfill the sizing of a reduced scale test bench allowing to achieve the PHIL real-time emulation. The original "time compression" concept is also reminded. However, the main contribution of this article is the comparison between two concepts of real-time emulated devices (RTED) depending on whether these concepts are based on a model ("model based" RTED) or on a physical image of the actual device ("image based" RTED). Advantages and drawbacks of both concepts are discussed based on experimental results.

This paper presents a scaling methodology based on dimensional analysis and applicable to systems’ mathematical models. The main goal of this research is to propose time-accelerated and size-scaled HIL (Hardware In the Loop) experiments, while keeping similarity with respect to the dynamics of the original system. The scaling process is presented using a simple wind turbine model. The scaling method is validated through simulations in which a wind turbine model and an electrochemical battery model are connected together. Finally, an experimental real-time validation is performed using physical emulators.

In the context of aviation, this article looks at replacing a ram air turbine (RAT) with a hybrid proton-exchange membrane (PEM) hydrogen/oxygen (H2/O2) fuel cell and ultracapacitor system, starting from a theoretical perspective. The structure we propose has two static power converters: one associated with fuel cells and the other with ultracapacitors. The energy management principle presented (frequency sharing) enables two types of control. First, the converter associated with the fuel cell manages the voltage of the dc bus, and then the converter associated with the ultracapacitors controls the high-frequency currents. Second, the voltage of the dc bus is oppositely controlled by the ultracapacitor converter.

This paper presents a dimensional-analysis supported scaling procedure applied to a mathematical model of electrochemical batteries. The main objective of this research is to allow for laboratory size-scaled and time-compressed experimental analysis of processes involving large physical magnitudes and evolving over long time spans. These situations are of interest when considering the sizing of battery packs and other components of energy systems, particularly smart grids, and further systems where battery storage is relevant, like hybrid vehicles and other standalone systems, as well as deciding management strategies on them. Voltage-, current- and time-scaled models preserving the dynamic evolution of a group of relevant physical magnitudes are presented. These models have been validated through simulation and physical experiments on a test-bench designed and constructed on purpose. The physical implementation of the scaled models is not possible in the cases where some of the scaled model parameters cannot be met using real batteries. But, as the mathematical construction of the scaled models is always possible, this problem can be circumvented with a Hardware-in-the-loop approach: the scaled battery is numerically emulated on a programmable and controllable power source/sink system, which is run in real-time embedded in the test-bench representing the whole system under study.

The optimal design of multisource systems, hybrid systems in particular, requires an adequate choice of the energy management strategy. This latter usually impacts source sizing and lifetime. The present paper deals with an energy management approach based on a frequency sharing of the mission. Firstly, the limits of a symmetric frequency energy management are presented in the case of a hybrid system associating a fuel cell with a Li-Ion battery. Subsequently, an original energy "asymmetric" management strategy for the optimal sizing of this association is presented. This strategy is then tested on the "Hydrogen" platform at the LAPLACE research laboratory. Finally, the two energy management strategies are compared in the context of an integrated design by optimization; the asymmetric strategy offers significant gains in terms of system weight, which is important for embedded applications.

The knowledge of the dynamic behavior of batteries is essential for their correct operation and management, to which aim mathematical models are invaluable tools. This paper presents an improvement of an already existing, commonly used dynamic battery model. The modification allows a better reproduction of the battery output voltage during charge and discharge processes without increasing the model complexity. Three parameter estimation methods are presented for both models. Also results of experimental tests are presented, which were performed in order to provide data for these three estimation methods and for validation purposes.

This paper deals with a hybrid electrical network for an aircraft in emergency operation. The principle of this network is to hybridize, through a bidirectional DC/DC converter, a high speed Ram Air Turbine (RAT) with an electrochemical Lithium Ion accumulator. A design study of DC/DC power converters, according to the voltage of the accumulator, is presented. The results of this study have shown that utilization of a medium-voltage battery can be a good mass / efficiency trade off of the overall system. Some experiments on a lab test bench have allowed validating the principle of the hybridization and several energy management strategies have been tested with low and medium voltage lithium ion batteries.

Electrical systems in aeronautics have known an important development in these recent years, which required the development of complex architectures as HVDC networks (High Voltage Direct Current). This type of architecture enables the delivery of electricity from the source to the equipment. However, the integration of many different types of equipment increases the risk of instability problems on DC network disturbed power. This paper presents the different structures used and the different rules adopted to ensure the stability constraints of the entire system. An experimental validation of interaction analysis between two devices connected to a single DC bus is presented to support the theoretical results.