WorldCat Identities

Locatelli, Marie-Laure (1964-...).

Overview
Works: 18 works in 29 publications in 2 languages and 30 library holdings
Roles: Thesis advisor, Opponent, Author
Publication Timeline
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Most widely held works by Marie-Laure Locatelli
Etude des propriétés électriques d'un matériau polyimide à haute température : application à la passivation des composants de puissance en carbure de silicium by Samir Zelmat( Book )

3 editions published between 2006 and 2007 in French and held by 3 WorldCat member libraries worldwide

The aim of this work is to evaluate the polyimide potentialities as a passivation layer for silicon carbide power devices, under temperatures and electric fields definitely higher than those achieved in silicon based power device environment (until 350°C and 3 MV/cm respectively). In order to quantify the polyimide inherent properties, electrical characterizations were carried out in a range of temperature extended up to 260°C, on MIM structures (Metal Insulator Metal) using polyimide films cured in a standard process. The results show good electrical properties at ambient temperature and up to 180°C. However, high dielectric losses and permittivity are achieved beyond 180°C. An improvement of the dielectric and the insulation properties was however observed after an additional thermal treatment, in which the samples are slowly exposed at elevated temperatures, indicating that the material is unstable after the standard imidization cure of polyimide film
Réalisation de jonctions pn dans le SiC-6H par implantation ionique d'aluminium Pn junction creation in 6H-SiC by aluminium ion implantation by Laurent Ottaviani( Book )

3 editions published in 1999 in French and held by 3 WorldCat member libraries worldwide

L'implantation ionique est la seule technique de dopage local maîtrisable avec le carbure de silisium, la diffusion thermique nécessitant des températures trop élevées pour une industrialisation du procédé. Les principaux atomes dopant utilisés sont l'aluminium et le bore pour le type p, et l'azote pour le type n. Un problème important lié à cette technique réside dans l'activation électrique de l'espèce implantée. La création de l'émetteur de la diode bipolaire p+nn+ étudiée exige cinq implantations successives d'aluminium, dont les énergies sont échelonnées entre 25 et 300 keV, afin d'obtenir un profil rectangulaire à concentration constante sur une distance précise. Ce dopage volumique est un dopage visé, c'est-à-dire qu'il est donnée dans le cas où l'ionisation est complète. Or, les doses et énergies d'implantation utilisées conduisent à l'endommagement du cristal, et même à son amorphisation sur une certaine profondeur
Etude du comportement électrique du transistor bipolaire de puissance en haute température = tudy of the bipolar power transistor electrical behaviour at high temperature by Marie-Laure Locatelli( Book )

2 editions published in 1993 in French and held by 2 WorldCat member libraries worldwide

The high temperature power device field concerns both the high ambient temperature applications an the systems opera ting at usual ambient temperature for which an increase in the power-to-weigh ratio is needed. In this frame, we particularly examined the electrical behaviour of the bipolar power transistor in the [30°C, 260°C] temperature range. We studied and analysed from a physical point view the on- and off-state characteristics, as also the switching characteristics under resistive and inductive load . An evaluation of the device dissipation versus junction temperature was made for each Phase of its switching operation Having left away all ageing and reliability problems, this study showed that the bipolar power transistor functionality is maintained in all the temperature range, though a perceptible performance diminution. The increase in power dissipation when the temperature is augmented leads to a limitation of the advantage of a high temperature operation of the component. Silicon, which is the sole semiconductor used for existing power devices, is personally involved especially because of its intrinsic carrier concentration and carrier mobility dependences on temperature. The analysis of the high temperature bipolar power transistor electrical characteristics, and the knowledge of the silicon carbide physical properties let us deduce the theoretical advantages of such a new semiconductor with regard to improvement of the bipolar power transistor performance at high temperature
Étude des matériaux isolants d'encapsulation pour la montée en température des modules de puissance haute tension by Mireille Bechara Keyrouz( Book )

2 editions published between 2011 and 2017 in French and held by 2 WorldCat member libraries worldwide

This thesis presents a selection and characterization of electrically insulating materials able to assure the encapsulation for high voltage components and modules operating at high junction temperatures. This work makes a survey of the solid insulating materials that are commercially available. The initial review outlines that a compromise needs to be achieved between the material physical limits at high temperature and its hardness. So a first objective of the present study is to identify and characterize a flexible material for volume encapsulation of high voltage devices with a minimum operating temperature of 250°C. A second objective is to identify and characterize another material for surface encapsulation suitable for lower voltage appliqtions (<1,2 kV) with a higher operating temperature between 300 and 350°C. Two silicone-based elastomers with SiO2 dispersed particules, and a semi-crystalline polymer (fluorinated parylene, PA-F), are both retained for this study. The analysis of the high temperature dielectric properties, are performed for the first time on these materials. A correlation between the electrical properties and the physico-chemical and structural evolution of these materials is realized. For the study on silicone-based e1astomers with SiO2 dispersed particules, the thermal characterizations allow to determine their temperature working range from -60°C to 250°C in air. The dielectric properties have a similar behavior for both elastomers and the various phase transitions at low temperatures are identified (-150°C to 25°C). At high temperatures (25°C to 300°C) and at low frequencies, a relaxation around 120°C appears, that is related to the absorption of humidity, thus sensitive to the preconditioning of the material. It was possible to evacuate the absorbed water through a suitable annealing at temperatures above 120°C. The DC conductivity at 300°C is in the range of 10-13 omega-1.cm-1. These low values show the interest of these silicone-based elastomers for electrical insulation at high temperatures. As regards to the PA-F, the thermal characterizations confirm that this material is stable for temperatures up to 350 °C in air. The electrical measurements allow to determine the values of DC conductivity up to 350 °C. The DC conductivity value is lower than 10-12 omega-1 cm-1, meaning that PA-F is an insulating material even at such high temperatures. Moreover the PA-F exhibits dielectric breakdown strength between 2 and 4 MV.cm-1 up to 350°C Besides, when increasing the film thickness up to 50 um, the PA-F shows an improvement of the dielectric properties at low fields. This effect is attributed to an increase of the volume fraction of the crystalline phase driven by the film thickness. The decreases in the DC conductivity as well as an increase in the die1ectric breakdown strength are correlated to the crystallization kinetics during a high temperature annealing. This phenomenon appears beneficial for the electrical insulation properties. So the PA-F exhibits exceptional initial dielectric properties up to 350°C, offering a possible solution for surface encapsulation. Further works should confirm this with a long term properties stability study at high temperature
Etude du comportement sous haute température de matériaux polyimides en vue de la passivation de composants de puissance à semi-conducteurs grand gap by Sombel Diaham( Book )

2 editions published in 2007 in French and held by 2 WorldCat member libraries worldwide

L'objectif de cette étude a été d'évaluer les potentialités d'utilisation d'une nouvelle résine polyimide (PI) dans le but d'assurer le rôle de couche de passivation des composants de puissance en carbure de silicium (SiC) fonctionnant au-delà de 200°C. De tels composants représentent un enjeu pour répondre aux besoins de l'électronique de puissance avec des systèmes plus intégrés ou capables de fonctionner à des températures ambiantes plus élevées. Les mesures électriques effectuées ont permis de montrer que le PI présente une bonne compatibilité du point de vue de la fonctionnalité électrique avec des valeurs du champ de rupture EBR comprises entre 2 et 4 MV/cm jusqu'à 400°C. Par ailleurs, des conductivités électriques statiques (DC) typiques de celles des matériaux semi-isolants (10-12 à 10-8 O-1.cm-1) ont été observées entre 200 et 400°C. L'une des contributions majeures du travail de caractérisation, appuyé par une compréhension des phénomènes physico-diélectriques, a été de montrer la corrélation entre les mesures de conductivité DC du PI effectuées à l'aide de deux techniques de mesure différentes (courants de conduction et spectroscopie diélectrique). La spectroscopie diélectrique, couplée à une modélisation des phénomènes de polarisation aux électrodes, apparaît ainsi comme un outil de mesure rapide et efficace pour déterminer la conductivité électrique des isolants à hautes températures. Le second temps de l'étude a concerné la détermination de la limite d'utilisation du PI du point de vue de la stabilité de ses propriétés électriques dans le temps à hautes températures et selon la nature de l'atmosphère (inerte ou oxydante). Lors des mesures sous contraintes isothermes, les films de PI ont montré des comportements différents selon la température et/ou la nature de l'atmosphère du milieu environnant. Il a tout d'abord été observé qu'aucune utilisation ne pouvait être envisagée à 400°C car les films présentent rapidement des dégradations dues à la thermolyse quelle que soit l'atmosphère. En revanche, à 300°C sous azote, les propriétés électriques restent relativement stables
Etude de la tenue en tension des dispositifs de puissance en carbure de silicium par caractérisations OBIC et électriques = Study of the breakdown voltage of the silicon carbide power devices by OBIC and electrical characterizations by Karine Isoird( Book )

2 editions published in 2001 in French and held by 2 WorldCat member libraries worldwide

The purpose of this study is the increase of the breakdown voltage of silicon carbide power devices. It has been devoted both to the determination of physical parameters of material (the electrons and holes ionization rate) and to the analysis of the bipolar diodes behavior under reverse biases. To reach these two aims, my first work consisted in the installation of automatic experimental OBIC (Optical Beam Induced Current) setup. The bibliographical study of various methods of extraction of the ionization rate in other materials contributed to determine a process adapted to SiC and which tends to minimize the errors produced by the simplifying assumptions. For that we designed and fabricated a specific device (Schottky diode with contact semi-transparent). We obtain the variations of the multiplication factor (M) versus reverse bias from measurements of the current optically induced in this device polarized in reverse. The ionization rate is extracted from these measurements. The parameters of this structure protected by the Junction Termination Extension (JTE) were optimized by simulation using software ISE. The study of the electric behaviors of several batches of 1,5 kV bipolar diodes whose junction termination (JTE) were carried out with Boron or Aluminum, revealed the impact of different post-implantation annealing on the reverse and forward behaviors. The OBIC method turned out effective in the study of the electric field distribution onto structures under tests, it revealed particularly the influence of different parameters (emitted doping profile, JTE doping level...) on the breakdown voltage of SiC samples. The last step of these works was the production and the characterization of diodes designed to block 5 kV
Élaboration et caractérisation de films polyimide-nitrure de bore nanocomposites pour l'isolation électrique à haute température by François Saysouk( Book )

2 editions published between 2014 and 2015 in French and held by 2 WorldCat member libraries worldwide

The advanced research for warm regions integration and/or operation in power electronics, results in an increased level of electrical and thermal stresses imposed on all their constituents. This concerns, in particular, the components of the power modules and high temperature rotating machines. In literature a thin dielectric layer for the high temperature (> 200 °C) isolation of different parts in power modules and rotating machines is missing. Polyimides, thermosetting polymer materials, are good candidates for this type of applications; however in this range of temperatures, these are limited from an electrical point of view. The introduction of inorganic nanoparticles in the polyimide matrix can be a solution to enhance its dielectric properties. The availability of new nanoparticles allows the fabrication of increased performance nanocomposites with high electric field and high temperature (up to 400 °C) performances. In this thesis, novel polyimide/boron nitride (PI/BN) nanocomposites have been prepared. Their dielectric properties were studied particularly in the range from 200 °C to 350 °C. Also, the influence of the size of the nanoparticles of BN (between 40 nm and 250 nm) has been studied. It's known that the presence of agglomerates in the nanocomposites limits the dielectric properties under high electric field; many improvements have been made in this direction to ameliorate the fabrication process. Dielectric losses, conduction currents and electrical conductivity improvements have been obtained in the nanocomposites compared to the neat matrix: a 2 to 4 decades reduction has been measured in the considered temperature range. Furthermore, the breakdown field resulted doubled at 350 °C for nanocomposites. Finally an analysis of the various physical mechanisms involved in the electrical conduction improvement was realised
Electrical Conductivity of Parylene F at High Temperature by S Diaham( )

1 edition published in 2010 in English and held by 2 WorldCat member libraries worldwide

Contribution à la conception et mise en oeuvre de structures de packaging pour la montée en tension des modules de puissance : contraintes sur les isolants by Hélène Hourdequin( Book )

2 editions published in 2018 in French and held by 2 WorldCat member libraries worldwide

The power electronics is at the beginning of a major evolution by the introduction of new power components semiconductor 'wide bandgap' in the systems. Indeed, the evolution of silicon carbide (SIC) technology allows to develop small chips, which can operate at a higher switching frequency, and support higher voltages than current one, limited during several decades by the physical properties of silicon. Therefore, the introduction of these components must be adapted to their environment in order to take into account these new performances. From an electrical point of view, the stresses imposed on insulating materials are close to their limits, particularly in the packaging configurations currently used in the power modules. The aim of this thesis is to propose an original solution allowing to integrate the 15 KV components currently in development phase, in a structure such as power module. After studying some packaging solutions, the study focused on a particular area, called the triple point between the metallization, the substrate and the encapsulation materials. We propose, from simulations by the finite element method analysis, a new geometry for the metallized ceramic substrate able to reduce the electric field intensity at the triple point. The structure modification consists in the creation of a gap in the substrate at the edge of the metallization. This new geometric structure has shown by simulation a significant reduction of the electric field intensity at the triple point thanks to a better spreading of the equipotential lines. After reviewing several technical manufacturing, ultrasonic machining was selected, this process is particularly efficient for hard and brittle materials such as ceramics and provides an etching profile with an excellent alignment to the edge of the metallization with the ceramic. Experimental results based on samples tests made it possible to carry out tests showing interesting and encouraging results in terms of partial discharges and resistance to dielectric strength. Thanks to the simulation under FEM analysis and after first experimental results, the new geometric structure for the metallized ceramic substrate proposed for the high voltage power modules, seems to be a technologically integrable solution for the optimization of the packaging for the purpose of the voltage rise in module. Moreover, the interest of the proposed solution compared with other published strategies, such as the use of innovative encapsulation materials was discussed, as well as the advantage offered of being able to combine the strengths of two types of approaches
Etude de l'impact des paramètres de protection périphérique et environnementaux de composants de puissance en carbure de silicium en vue de leur montée en tension by Lumei Wei( Book )

2 editions published in 2017 in French and held by 2 WorldCat member libraries worldwide

Nowadays, most of the semiconductor devices used in power electronics are silicon (Si) based devices. In order to meet the new electrical and thermal constraints induced by the demand in rising both the operating voltage and the power density of the electrical energy converters, the use of wide band gap semiconductors such as silicon carbide (SiC) may represent an adequate solution, thanks to their critical electric field (EC) which is about ten times higher than that of Si and to their ability of operating at temperatures beyond 200 °C. A state-of-the-art on the readily (commercially) available high voltage SiC diodes (10kV or higher) is presented, highlighting the progress made in improving the materials themselves as well as their peripheral protection. However, regarding the die insulating materials, the studies mainly focus on the primary passivation step, which was often mentioned as the most critical one. Obviously much less work is carried out on the impact of the secondary passivation and encapsulation materials. The goal of this study is to contribute to a better knowledge of the mechanisms involved in the SiC chips and electrically insulating environment breakdown while in a blocking state, as well as to the identification of the most relevant parameters acting on these phenomena. Thus, a study of the correlated properties of the semiconductor and the passivation and encapsulation materials present on the surface of the chip was carried out on SiC-4H bipolar diodes protected by junction termination extension (JTE), supplied by IBS society, within the framework of the 'FilSiC' research project. First, a numerical simulation study of the entire structure (SiC and insulating materials) was carried out using the Sentaurus Device software (Synopsys). This allowed for quantifying the electric field stresses throughout the structure for a given applied voltage as well as their dependence on the properties of the considered insulating materials. This study was equally used for choosing the appropriate parameters of the epitaxial substrate and for designing the lateral and the surface geometry of the diodes (the technological parameters being fixed elsewhere), in view of the subsequent experimental study of their breakdown voltage in the 1kV-6kV range. Concurrently, the electrical characterization of the primary passivation material used (thick silicon dioxide layer) was performed by using MIS (metal-insulator-semiconductor) type structures, in a temperature range of up to 300 °C. This allowed to determine its main electrical properties, particularly the dielectric breakdown voltage. The work then focused on the room-temperature characterization of the breakdown voltage of the full structures built around the different manufactured diodes. The tests were carried out both under high vacuum conditions and under nitrogen at atmospheric pressure. The behavior of the different study cases observed under vacuum conditions during the breakdown, coupled with the simulation results, allowed to determine the values of the maximum electric fields induced in the different insulating materials and to correlate them to their known dielectric breakdown values. On the other hand, additional results obtained under nitrogen atmosphere confirmed some technological parameters and mechanisms at play during the breakdown of the diodes. Several guidelines for the optimization of these technological parameters (epitaxy and JTE) and of the insulating passivation and encapsulation layers (thickness, permittivity) of the "high voltage" SiC diode were derived from this study
Amélioration des performances des convertisseurs HVDC mis en oeuvre pour le raccordement des parcs éoliens offshore lointains : évaluation du potentiel des nouveaux composants IGCT by Davin Guedon( )

1 edition published in 2022 in English and held by 1 WorldCat member library worldwide

For more than a decade, high-voltage direct-current (HVDC) grid-connection of offshore wind farms has intensified. It allows transporting to the mainland power levels around 1 GW, over underwater distances exceeding 50 kilometres. A key issue related to the sizing of HVDC converter-stations, based on MMC (Modular Multilevel Converters), is their efficiency. Only 0.1% of power losses represents several GWh lost for each year of operation of the wind farm. These power losses are related to the characteristics of the semiconductors used. Today, the IGBT (Insulated-Gate Bipolar Transistor) is the only semiconductor device used in this type of application. Historically, the IGBT has been developed for medium-power industrial applications, and does not appear as the best candidate to realize HVDC systems. On the other hand, the IGCT (Integrated Gate-Commutated Thyristor) has performances and features that seem better adapted, however its use in such systems has never been considered. The aim of this PhD thesis is to optimize the performances of HVDC converters, based on IGCT, as part of the gridconnection of offshore wind farms. This work has been the subject of a collaboration between the LAPLACE Laboratory in Toulouse, Electricité de France Research & Development (EDF R&D), and the semiconductor manufacturer Hitachi ABB Power Grids, Semiconductors. In a first approach, the static and dynamic characteristics of the IGCTs have been measured experimentally on a double-pulse test bench. Then, an electro-thermal model has been built, in order to determine precisely the power losses in the hundreds of sub-modules present in an MMC arm. This approach has allowed a comparison of different IGCTs, according to their power losses, taking into account the intermittent production of the offshore wind farm. Following this study based on calculations and simulations, a test bench in steady-state, consisting of two IGCT-based sub-modules connected in a back-to-back configuration, has been designed and implemented to accurately measure on-state and switching losses through dedicated instrumentation. With a working voltage up to 5 kV and currents exceeding 2 kA, 4.5 kV and 10 kV devices have been tested under operating conditions equivalent to those of a 1 GW HVDC station. The power loss measurements using the calorimetric method have confirmed the validity of the electro-thermal models related to IGCT and its clamp circuit, with an accuracy of about 10%. The waveforms have highlighted larger deviations regarding the switching losses, caused by the stray inductances of connection within the switching cell. The cross-use of electro-thermal models and experimental measurements demonstrates that 4.5 kV IGCTs can allow a significant rise in the power levels of the MMC-based HVDC stations, while 6.5 kV and 10 kV IGCTs are the most suitable devices for prospective applications, guided by the voltage upgrade of HVDC cables. Soft switching circuits are promising to reduce the volume of the sub-modules, and would be particularly relevant for 6.5 kV and 10 kV devices, whose switching losses are the main limiting factor
Étude du vieillissement de polymères isolants utilisés dans le packaging des modules de puissance haute température by Rabih Khazaka( Book )

1 edition published in 2011 in French and held by 1 WorldCat member library worldwide

La recherche permanente de l'intégration et/ou du fonctionnement dans des régions chaudes des dispositifs électroniques de puissance se traduit par une augmentation du niveau des contraintes électriques et thermiques imposées à tous leurs constituants. Cela concerne en particulier les constituants des modules de puissance. Comme suite à une étude bibliographique qui a permis d'analyser les différentes structures de packaging pouvant être adaptées à un fonctionnement à haute température, il ressort en particulier un besoin en couches diélectriques minces afin d'isoler les différentes parties du module. Dans ce contexte, les travaux ont porté sur la détermination de la limite d'utilisation en température de deux matériaux diélectriques polymères (un polyimide BPDA/PDA et un parylène fluoré PA-HT), pouvant être aptes à constituer la couche de passivation des puces de carbure de silicium, ou la couche intermétallique ou de protection de surface au sein des modules de puissance. Afin de parvenir à ce but, des caractérisations électriques à l'instant initial (t0) ont été menées sous hautes températures, jusqu'à 400 °C. Ensuite, l'évolution des propriétés (en particulier électriques) des matériaux durant le vieillissement thermique et thermo-oxydatif, à des températures supérieures ou égales à 250 °C, pour des milliers d'heures, a été mesurée et analysée. A t0, le champ de rupture moyen des matériaux reste élevé et supérieur à 2 MV/cm à 300 °C, pour les films les plus épais testés (8 µm). La conductivité DC, dans une gamme de température entre 300 °C et 400 °C, montre un comportement semi-résistif pour le BPDA/PDA et un comportement qui passe d'isolant à semi-résistif pour le PA-HT. Durant le vieillissement sous N2, aucune dégradation du BPDA/PDA n'est observée jusqu'à 360 °C. A 300 °C sous air, une stabilité de la tension de rupture lorsque ce dernier est vieilli sur substrat en silicium (Si), et une dégradation lente dépendante de l'épaisseur initiale lors du vieillissement sur substrat en acier inoxydable (A. I. ) sont observées. La dégradation se révèle surfacique liée à la présence de l'oxygène ambiant. Elle est d'autant plus prononcée que la température du vieillissement augmente, et apparaît alors également sur les substrats en Si. Le PA-HT déposé sur un substrat en A. I. A été vieilli sous air entre 300 °C et 360 °C. L'étude montre que ces films paraissent prometteurs pour les applications à 300 °C, avec une cristallisation isotherme qui affecte favorablement les propriétés diélectriques du matériau. Pour les températures plus élevées, une dégradation activée thermiquement apparaît et les films inférieurs à 5 µm d'épaisseur, ne peuvent pas dépasser 1000 heures de vieillissement sous air à 360 °C. Par conséquent, en se basant sur les propriétés électriques intrinsèques ainsi que sur leur évolution en vieillissement isotherme, les films de BPDA/PDA et de PA-HT semblent appropriés pour fonctionner pendant de longues durées à 300 °C sous air. Pour les températures plus élevées (360 °C), la stabilité sous air pour de longues durées reste problématique en particulier sur A. I. Par ailleurs, des solutions permettant de limiter la dégradation thermo-oxydative ou paraissant plus prometteuses, ainsi que des traitements thermiques permettant l'amélioration de la résistivité électrique à haute température à t0 sont proposés
Nouvelle électrification en courant continu moyenne tension pour réseau ferroviaire by Andrea Verdicchio( )

1 edition published in 2019 in French and held by 1 WorldCat member library worldwide

Since the beginning of the 20th century, various DC and AC rail electrification systems have beendeveloped in Europe. Single-phase, medium-voltage AC systems (25 kV-50 Hz or 15 kV 16.7 Hz)allow the use of a light overhead-line of small copper cross-section but by their principle involvefluctuating power and reactive power that have to be compensated by large and expensivedevices. DC electrification systems (1.5kV or 3kV) do not have these disadvantages but in return,their relatively low voltage level involves the circulation of high currents in the overhead-line whichlimits any increase in traffic because the copper section cannot be increased beyond 1000 mm2.From a rolling stock point of view, AC powered locomotives have a complex and voluminousconversion chain (step-down transformer, rectifier, low-frequency filter and traction inverter). Onthe other hand, a conversion chain operating under direct current catenary is reduced to an inputfilter and a traction inverter. Today, the technological progress made in the field of powerelectronics makes it possible to envisage the development of medium voltage DC grids to supportthe energy transition by integrating more easily renewable energy sources and storage devices.On the basis of this observation, the aim of this thesis is to propose a new medium voltage DCrailway electrification system, on the one hand, with the aim of combining the advantages of thecurrent railway electrification systems and on the other hand, to consider in the medium term therenovation of lines electrified in DC. The first chapter of this thesis presents a state of the art ofexisting railway electrification systems and associated traction chains. The second chapterhighlights the interest of a medium voltage DC electrification for railway traction. A calculationmethod for determining the DC voltage level for a given traffic is proposed. Therefore, it is shownthat the choice of a voltage level at 9 kV makes it possible to obtain an overhead-line cross-section and a substation spacing comparable to the 25 kV-50 Hz system. In its first part, the thirdchapter proposes a strategy to upgrade the existing 1.5 kV French electrification system to a 9 kVsystem. Until the fleet of traction units is adapted to operate at 9 kV, it is possible to prepare theevolution of the electrification system by deploying a transmission line at 9 kV (feed-wire) inparallel with the existing 1.5 kV overhead-line. At the end of the transition period, the 1.5 kVvoltage level is completely removed and the entire infrastructure as well as the traction unitsoperate at 9 kV. The second part of this chapter is dedicated to the study of a topology, based onan association of isolated DC/DC converters, to fulfil the function of solid state transformer whichis essential for the power reinforcement of the 1.5 kV system from the 9 kV feed-wire. The fourthchapter presents the realization and tests of an isolated DC / DC converter with a power level of300 kW using 3.3 kV SiC MOSFET modules. A general conclusion and perspectives conclude thismanuscript
Étude du vieillissement de polymères isolants utilisés dans le packaging des modules de puissance haute température by Rabih Khazaka( )

1 edition published in 2012 in French and held by 1 WorldCat member library worldwide

La recherche permanente de l'intégration et/ou du fonctionnement dans des régions chaudes des dispositifs électroniques de puissance se traduit par une augmentation du niveau des contraintes électriques et thermiques imposées à tous leurs constituants. Cela concerne en particulier les constituants des modules de puissance. Comme suite à une étude bibliographique qui a permis d'analyser les différentes structures de packaging pouvant être adaptées à un fonctionnement à haute température, il ressort en particulier un besoin en couches diélectriques minces afin d'isoler les différentes parties du module. Dans ce contexte, les travaux ont porté sur la détermination de la limite d'utilisation en température de deux matériaux diélectriques polymères (un polyimide BPDA/PDA et un parylène fluoré PA-HT), pouvant être aptes à constituer la couche de passivation des puces de carbure de silicium, ou la couche intermétallique ou de protection de surface au sein des modules de puissance. Afin de parvenir à ce but, des caractérisations électriques à l'instant initial (t0) ont été menées sous hautes températures, jusqu'à 400 °C. Ensuite, l'évolution des propriétés (en particulier électriques) des matériaux durant le vieillissement thermique et thermo-oxydatif, à des températures supérieures ou égales à 250 °C, pour des milliers d'heures, a été mesurée et analysée. A t0, le champ de rupture moyen des matériaux reste élevé et supérieur à 2 MV/cm à 300 °C, pour les films les plus épais testés (8 µm). La conductivité DC, dans une gamme de température entre 300 °C et 400 °C, montre un comportement semi-résistif pour le BPDA/PDA et un comportement qui passe d'isolant à semi-résistif pour le PA-HT. Durant le vieillissement sous N2, aucune dégradation du BPDA/PDA n'est observée jusqu'à 360 °C. A 300 °C sous air, une stabilité de la tension de rupture lorsque ce dernier est vieilli sur substrat en silicium (Si), et une dégradation lente dépendante de l'épaisseur initiale lors du vieillissement sur substrat en acier inoxydable (A.I.) sont observées. La dégradation se révèle surfacique liée à la présence de l'oxygène ambiant. Elle est d'autant plus prononcée que la température du vieillissement augmente, et apparaît alors également sur les substrats en Si. Le PA-HT déposé sur un substrat en A.I. a été vieilli sous air entre 300 °C et 360 °C. L'étude montre que ces films paraissent prometteurs pour les applications à 300 °C, avec une cristallisation isotherme qui affecte favorablement les propriétés diélectriques du matériau. Pour les températures plus élevées, une dégradation activée thermiquement apparaît et les films inférieurs à 5 µm d'épaisseur, ne peuvent pas dépasser 1000 heures de vieillissement sous air à 360 °C. Par conséquent, en se basant sur les propriétés électriques intrinsèques ainsi que sur leur évolution en vieillissement isotherme, les films de BPDA/PDA et de PA-HT semblent appropriés pour fonctionner pendant de longues durées à 300 °C sous air. Pour les températures plus élevées (360 °C), la stabilité sous air pour de longues durées reste problématique en particulier sur A.I. Par ailleurs, des solutions permettant de limiter la dégradation thermo-oxydative ou paraissant plus prometteuses, ainsi que des traitements thermiques permettant l'amélioration de la résistivité électrique à haute température à t0 sont proposés
Impact de la modélisation physique bidimensionnelle multicellulaire du composant semi-conducteur de puissance sur l'évaluation de la fiabilité des assemblages appliqués au véhicule propre by Kamal El Boubkari( )

1 edition published in 2013 in French and held by 1 WorldCat member library worldwide

A bord des véhicules électriques (VE) et Hybrides (VEH), les fonctions de tractions sont assurées par des convertisseurs électroniques de puissances. Ces derniers sont constitués de module de puissance (IGBTs ou MOSFETs). Au cours de leur fonctionnement, ces modules sont parfois soumis à de fortes contraintes électriques et thermiques qui amènent à une défaillance ou même à une destruction. Le premier objectif sera de réaliser un banc expérimentale permettant d'étudier le vieillissement des modules IGBTs en régîmes extrêmes de fonctionnement (mode de court-circuit). Ainsi, nous évaluerons les différents indicateurs de vieillissements permettant de prédire la défaillance du composant. Il sera question aussi de suivre le vieillissement ou une dégradation initié sur les composants IGBTs par thermographie infrarouge. Le second objectif sera de modéliser et simuler par éléments finis différentes structures d'IGBTs, afin de valider les modèles en fonctionnement statique et dynamique. L'avantage de l'approche multicellulaire par rapport à l'approche unicellulaire sera mis en avant
Etude du comportement sous haute température de matériaux polyimides en vue de la passivation de composants de puissance à semi-conducteurs grand gap by Sombel Diaham( )

1 edition published in 2009 in French and held by 1 WorldCat member library worldwide

The aim of this study deals with the evaluation of the feasibility of using a new polyimide (PI) resin as a passivation layer for silicon carbide (SiC) semiconductor power devices operating above 200°C. Such components seem to be adapted to the needs of power electronics with more integrated systems or able to operate at higher environmental temperatures. The electrical measurements performed have shown that PI presents a good dielectrical rigidity with values of the breakdown field EBR in the range between 2 and 4 MV/cm up to 400°C. In addition, values of the static (DC) electrical conductivity typical of those of semi-insulating materials (10-12 to 10-8 O-1.cm-1) have been observed between 200 and 400°C. One of the main contributions of this experimental work, supported by an understanding of the physico-dielectrical phenomena, has been to show the correlation between the DC conductivity measurements performed in PI using two different techniques (conduction current measurements and dielectric relaxation spectroscopy). Dielectric relaxation spectroscopy, coupled to a modeling of electrode polarization phenomena, appeared also as a quick and powerful tool to determine the electrical conductivity in insulators at high temperature. The second step of the study focused on the evaluation of the operating limit of PI in the point of view of the electrical property stability versus time at high temperature and as a function of the atmosphere nature (inert or oxidant gases). First, it has been shown that the targeted PI properties were not suitable at 400°C mainly because of a rapid occurrence of the material thermolysis whatever the environment atmosphere nature. By contrast, at 300°C in nitrogen, electrical properties remained relatively stable. In air, an atypical improvement versus time has been observed
Etude de la tenue en tension des dispositifs de puissance en carbure de silicium par caractérisations OBIC et électriques tudy of the breakdown voltage of the silicon carbide power devices by OBIC and electrical characterizations by Karine Isoird( )

1 edition published in 2003 in French and held by 1 WorldCat member library worldwide

The purpose of this study is the increase of the breakdown voltage of silicon carbide power devices. It has been devoted both to the determination of physical parameters of material (the electrons and holes ionization rate) and to the analysis of the bipolar diodes behavior under reverse biases. To reach these two aims, my first work consisted in the installation of automatic experimental OBIC (Optical Beam Induced Current) setup. The bibliographical study of various methods of extraction of the ionization rate in other materials contributed to determine a process adapted to SiC and which tends to minimize the errors produced by the simplifying assumptions. For that we designed and fabricated a specific device (Schottky diode with contact semi-transparent). We obtain the variations of the multiplication factor (M) versus reverse bias from measurements of the current optically induced in this device polarized in reverse. The ionization rate is extracted from these measurements. The parameters of this structure protected by the Junction Termination Extension (JTE) were optimized by simulation using software ISE. The study of the electric behaviors of several batches of 1,5 kV bipolar diodes whose junction termination (JTE) were carried out with Boron or Aluminum, revealed the impact of different post-implantation annealing on the reverse and forward behaviors. The OBIC method turned out effective in the study of the electric field distribution onto structures under tests, it revealed particularly the influence of different parameters (emitted doping profile, JTE doping level...) on the breakdown voltage of SiC samples. The last step of these works was the production and the characterization of diodes designed to block 5 kV
Transformateurs électroniques pour applications ferroviaires by Caroline Stackler( )

1 edition published in 2019 in French and held by 1 WorldCat member library worldwide

Actuellement, la majorité des convertisseurs embarqués dans des trains circulant sous une caténaire alternative est composée d'un transformateur basse fréquence, puis de redresseurs,alimentant des moteurs de traction via des onduleurs de traction. Les inconvénients majeurs de ces structures sont un volume et une masse embarqués importants, dus au transformateur fonctionnant en basse fréquence. Le rendement est également mauvais, à cause des contraintes de volume et de masse. Grâce aux développements des semiconducteurs haute tension et forte puissance et des transformateurs moyenne fréquence, i.e. de l'ordre de quelques kilohertz, de nouvelles topologies de convertisseurs embarqués, appelées transformateurs électroniques, sont à l'étude. Si plusieurs topologies ont déjà été étudiées dans la littérature, elles n'ont jamais été comparées. L'objectif principal de cette thèse est donc de proposer une méthodologie de dimensionnement des différentes topologies de transformateurs électroniques, afin de pouvoir les comparer. Un état de l'art des différentes structures proposées dans la littérature est présenté dans le premier chapitre de ce mémoire. Le chapitre 2 est consacré à la comparaison de structures indirectes. Pour cela, une méthodologie, permettant d'optimiser le dimensionnement de chaque structure afin de maximiser son rendement sous des contraintes de masse et de volume, a été développée. Elle est ensuite appliquée sur des topologies utilisant des MOSFET SiC, contrairement aux structures à IGBT Si développées dans la littérature. L'inductance magnétisante est considérée afin d'assurer un fonctionnement en commutation douce, et ainsi limiter les pertes. Un troisième chapitre propose un filtre actif innovant, intégré aux DC-DC du convertisseur. Celui-ci a pour but de réduire le volume du condensateur de filtrage des bus intermédiaires, et ainsi le volume total du convertisseur, sans dégrader la fiabilité intrinsèque de celui-ci. Son fonctionnement et son impact sur les pertes du DC-DC y sont étudiés. Enfin, le dernier chapitre est dédié à l'étude des interactions entre le convertisseur embarqué et l'infrastructure ferroviaire. Pour cela, des modèles d'infrastructure 25 kV-50 Hz ont été réalisés. Ceux ci comportent notamment un circuit original modélisant l'effet de peau dans la caténaire. Des résonances à certaines fréquences, caractéristiques de la géométrie du réseau et de la position du train sur celui-ci, ont été mises en évidence dans l'impédance vue par le train. Ces modèles ont aussi été implémentés dans un simulateur numérique, pour alimenter une maquette petite échelle de convertisseur. Ce type de test n'a, a priori, jamais été réalisé sur un transformateur électronique. Une conclusion générale et des perspectives sur les travaux présentés concluent ce mémoire
 
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