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Surveillance de la conformité au domaine de conception opérationnelle dans les véhicules intelligents
No full textInternational audienceAdvanced driver assistance systems (ADAS) and automated driving functions are becoming integral to modern vehicles. Ensuring their safety and reliability requires validating their operation within well-defined Operational Design Domains (ODD). Monitoring ODD compliance is crucial to determine when these functions can operate safely. This paper presents a systematic approach to ODD monitoring using a formalized, machine-readable ODD description and fuzzy logic. The method evaluates compliance and provides explanations for non-compliance. The approach introduces a two-level hierarchical ODD representation, a membership score quantifying compliance, and an explanation mechanism for identifying the primary factors contributing to non-compliance. The monitoring results are integrated into a Conditional Activation Control System (CACS), which governs function activation based on ODD compliance. The proposed system was implemented within a production vehicle and validated using real-world data, demonstrating its feasibility for deployment. By enabling clear, real-time assessments of ODD adherence, this approach supports safer and more reliable automated driving, promoting user confidence and regulatory compliance
Development of a Modular High Current DC Power Supply for Plasma Torch
No full textInternational audienceThis paper presents a modular and indigenous design of a 400 A / 120 V power supply for a plasma torch. The design employs three LLC resonant converters operating in parallel to power the plasma torch. The proposed design results in reduced electromagnetic component size, and offers convenience in fabrication, testing, and maintenance. Detailed calculations, simulation validation, and fabrication of a single 135 A / 120 V LLC converter module are evaluated and presented. The main features include the surge repression circuit, soft-switching for high efficiency, and dynamic response of the supply. The proposed system demonstrates practicality for highcurrent application in resource-constraint environments
Modelling of SiC and GaN Transistors Based on Pulsed S-Parameter Measurements
No full textInternational audienceFor the design of fast-switching inverters a precise model of power semiconductors is required. Based on pulsed S-parameter measurements in the frequency range of 2 MHz to 500 MHz a SiC MOSFET and a GaN HEMT have been characterized. As basis for precise modelling, measurements under varying load conditions have been taken for many operating points covering the pinch-off, ohmic, and active regions. The employed model to describe the transistor uses a circuit comprising 12 circuit elements. Thereby, the elements of the intrinsic transistor vary with the transistor's operating point and parameters describing the influence of the package are considered to be constant. The model parameters have been adjusted iteratively. A comparison of the obtained model with the original S-parameter measurements exhibits an excellent match
Trapezoidal Wave Operation of High-power Non-isolated DC/DC Converter for Current Stress Reduction
No full textInternational audienceAll-DC offshore wind farms are crucial for advancing large-scale offshore wind power in deep-sea applications. Overcoming the technical bottleneck of high-power DC/DC converters is essential for these farms. This paper presents a trapezoidal wave operation method for nonisolated DC/DC converters, introducing design constraints for minimum current stress and minimum root-mean-square (RMS) of current. These innovations significantly reduce converter current stress, enhancing the power capacity of DC/DC converter. The operation principle of two-phase and three-phase structures are introduced, and the effectiveness has been confirmed by simulation and experiment results
Three port converter control with automatic mode transition for interconnected and standalone DC microgrids
No full textInternational audienceVarious Three-Port Converters (TPCs) are proposed in literature, usually operated in standalone networks without their control clearly discussed. In this paper, a new control scheme, offering smooth and automatic mode transitions in standalone and interconnected DC Microgrids operation, is presented. The control is applied in a TPC that consists of a boost and a bidirectional buck-boost converter, integrating a PV string and a battery with the DC Microgrid. In contrast to other proposed control systems, the one suggested here guarantees the required function of maximum power point tracking and output regulation in all corresponding modes. The proper operation of the system is evaluated through simulation studies
Modeling and Evaluating GaN HEMTs for Efficient Multicell Battery Balancing with Dual-Active Bridge Converters
No full textViews and opinions expressedare however those of the authors only and do notnecessarily reflect those of the European Union. Neitherthe European Union nor the granting authority can beheld responsible for them. The authors also acknowledgeFlanders Make for the support to their research group.International audienceThis paper evaluates the feasibility of gallium nitride (GaN) high-electron-mobility transistors (HEMTs) in battery active balancing circuits. A comparative analysis of GaN models, including loss and efficiency, is presented, which demonstrates the superior performance of GaN-based solutions and highlights its potential in efficient and reliable battery management systems (BMSs)
Interference propagation in two stage PV inverters
No full textInternational audienceIn this paper, current harmonic propagation of a two stage PV inverter is investigated in both common mode and differential mode in the supraharmonics range [2 -150 kHz]. The harmonics of the DC/AC inverter are present in both common mode and differential mode. In most cases only inverter harmonics are considered in filtering. However, it is seen that DC/DC converter harmonic currents are present in common mode of the output current of the inverter at grid side. Therefore, appropriate common mode filtering is needed to take into account for DC/DC converter harmonics as well. This finding is simulated in MATLAB/Simulink and verified through a commercial PV inverter with PV emulator
Preclinical multi-organ Magnetic Resonance Elastography (MRE) at 7T: an original piezoelectric actuator design with dedicated sequences
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Politiques environnementales et transitions urbaines. Le cas de la désimperméabilisation des sols
No full textInternational audienceCette communication propose d’interroger les processus de transition urbaine à travers l’analyse d’un dispositif émergent : la désimperméabilisation des sols. Cette solution est aujourd’hui promue par les récits scientifiques, institutionnels et politiques où elle est présentée comme une opportunité de changement vers une ville résiliente et renaturée. Pourtant, sa mise en œuvre n’est pas généralisée. Cela semble lié à un déficit de cadrages méthodologiques permettant aux collectivités territoriales de se saisir pleinement de ce dispositif. Cette contribution s’appuie sur les premiers résultats d’un projet de recherche en cours, PerméPolis (ANR 2024-2028), qui vise à construire une méthode d’aide à la désimperméabilisation prenant en compte la diversité des enjeux (techniques, économiques, politiques, réglementaires, fonciers, etc.), l’ensemble des parties prenantes impliquées, ainsi que la complexité des échelles de gestion urbaine. A partir d’un corpus de projets analysés dans différentes villes françaises, construit par une enquête par entretien, il s’agira de comprendre et d’analyser les conditions et les moyens de mise en œuvre de cette désimperméabilisation, afin d’identifier les freins et les leviers à son adoption et à sa généralisation. L’objectif est d’éclairer les conditions possibles d’une mise en œuvre efficace de la désimperméabilisation des villes. L’hypothèse défendue ici est qu’une meilleure considération des conditions et des moyens de l’action (en particulier les moyens d’agir accordés aux pouvoirs publics locaux pour changer l’ordre établi) permettrait une mise en œuvre plus effective des politiques environnementales ; elle pourrait même en constituer la clé
Transitions en tension : “Sobriété numérique” au prisme des sciences de l’information et de la communication
No full textInternational audienceEn nous inscrivant à la fois dans la perspective de “formation discursive” foucaldienne et dans la théorisation de la “trivialité” jeanneretienne, nous choisissons d’analyser la “sobriété numérique”, non pas seulement en tant que syntagme sociotechnologique mais également en prenant en considération leur processus de construction conceptuelle et la construction sociale pluridisciplinaire de leur charge idéologique, à partir de “la vie triviale des êtres culturels” (Jeanneret, 2008) : en considérant la “sobriété numérique” comme un exemple quasi-paradigmatique d’une tension entre “transition écologique” et “transition numérique”, entre deux “êtres culturels”, à savoir la “sobriété” et le “numérique”. Ce panel vise donc à clarifier la responsabilité sociale et énonciative de l’emploi de ce syntagme sociotechnologique dans les productions scientifiques en SIC. Par ailleurs, dans l’ambition de contribuer à renouveler l’épistémisation des SIC, nous argumentons qu’il sera fortement heuristique d’examiner la question de “sobriété numérique” à partir d’un “paradigme écologique” afin de renforcer la responsabilité énonciative des SIC dans leur action académique