Contribution à la simulation électro-thermomécanique numérique 3d : appliquée à l'étude de la fiabilité des interrupteurs à semiconducteurs packages, utilisés en traction ferroviaire

La tendance actuelle dans le domaine du transport ferroviaire est d’intégrer des modules de puissance de plus en plus puissants dans des volumes de plus en plus réduits. Cela pose des problèmes, notamment en termes de fiabilité, car lors de leurs cycles de fonctionnement, les interrupteurs à semi-conducteurs et leur environnement immédiat sont soumis à des contraintes électro-thermo-mécaniques plus sévères. Cela peut entraine leur destruction et donc la défaillance de la fonction de conversion d'énergie. L’objectif principal de cette thèse est de décrire des modèles et des outils de simulation multi-physiques afin de caractériser ces contraintes. Nous avons choisi comme cas d’étude les fils de connexion dits «wire bonding». Ces fils sont, en effet, considérés comme l’un des points faibles en ce qui concerne la durée de vie des modules de puissance, utilisés dans les systèmes embarqués notamment dans le ferroviaire. Dans ce contexte multi-physique, nous avons développé des modèles, numériques, éléments finis, analytiques, 3D ou 1D, afin de déterminer les contraintes thermomécaniques lors du passage du courant dans ces fils. A travers les modèles décrits et les résultats de simulation présentés, nous caractérisons le comportement des fils d’un point de vue électrique, thermique, magnétique ou mécanique. Plus précisément les interactions électromagnétiques, électrothermiques, électromécaniques ou thermomécaniques entre modèles et entre outils de simulation sont discutées. Les résultats sont confrontés aux mesures thermiques et de déplacement. Ces dernières sont réalisées par le biais de prototypes expérimentaux. Le mode de sollicitation utilisé est dit actif. Un régime de courant, continu ou alternatif, est appliqué au système. La réponse thermique et mécanique du système est alors obtenue. Les conclusions de cette étude permettent d’une part de mieux caractériser le comportement électro thermomécanique des fils de bonding et de mieux comprendre l’origine des modes de défaillance de cette technologie d’interconnexion. D’autre part, une démarche d’utilisation des modèles et outils logiciels multi physiques pour une simulation électro thermomécanique est présentée. ABSTRACT : The trend in the field of railway transport is to integrate increasingly powerful power modules in smaller volumes. This is problematic, especially in terms of reliability: during their cycles of operation, the semiconductor switches and their immediate environment are subject to tougher electro-thermo-mechanical stresses. This can lead to their destruction and then, to the failure of the energy conversion function. The main goal of this work is to describe the models and multi-physics simulation tools to characterize these stresses. We chose as a case study the connection wire called “wire bonding”. These wires are, indeed, considered one of the weaknesses of the life time of the power module used in embedded systems, particularly in railway applications. In this multi-physics context, we have developed numerical, finite elements, analytical, 3D or 1D models to determine the thermo-mechanical stresses during the current flow through the wires. Thanks to the models described and the simulation results presented, we characterize the behavior of the wire for an electrical, thermal, magnetic or mechanical point of view. More precisely, the electro-magnetic, electro-thermal, electro-mechanical or thermo-mechanical interactions between models and between simulation tools are discussed. The results are compared to thermal and displacement measurements. They are realized thanks to experimental prototypes. The type of solicitation is called active. A system of direct or alternating current is applied to the system. The thermal and mechanical response of the system is obtained. The conclusions of this study allow, on the one hand, characterizing the electro thermo-mechanical behavior of wires bonding and understanding the origin of the failure modes of this technology. On the other hand, a way of using models and multi-physics software tools for an electro thermo-mechanical simulation is presented

Contribution à la simulation électro-thermomécanique numérique 3d (appliquée à l'étude de la fiabilité des interrupteurs à semiconducteurs packages, utilisés en traction ferroviaire)

La tendance actuelle dans le domaine du transport ferroviaire est d'intégrer des modules de puissance de plus en plus puissants dans des volumes de plus en plus réduits. Cela pose des problèmes, notamment en termes de fiabilité, car lors de leurs cycles de fonctionnement, les interrupteurs à semi-conducteurs et leur environnement immédiat sont soumis à des contraintes électro-thermo-mécaniques plus sévères. Cela peut entraine leur destruction et donc la défaillance de la fonction de conversion d'énergie. L'objectif principal de cette thèse est de décrire des modèles et des outils de simulation multi-physiques afin de caractériser ces contraintes. Nous avons choisi comme cas d'étude les fils de connexion dits wire bonding . Ces fils sont, en effet, considérés comme l'un des points faibles en ce qui concerne la durée de vie des modules de puissance, utilisés dans les systèmes embarqués notamment dans le ferroviaire. Dans ce contexte multi-physique, nous avons développé des modèles, numériques, éléments finis, analytiques, 3D ou 1D, afin de déterminer les contraintes thermomécaniques lors du passage du courant dans ces fils. A travers les modèles décrits et les résultats de simulation présentés, nous caractérisons le comportement des fils d'un point de vue électrique, thermique, magnétique ou mécanique. Plus précisément les interactions électromagnétiques, électrothermiques, électromécaniques ou thermomécaniques entre modèles et entre outils de simulation sont discutées. Les résultats sont confrontés aux mesures thermiques et de déplacement. Ces dernières sont réalisées par le biais de prototypes expérimentaux. Le mode de sollicitation utilisé est dit actif. Un régime de courant, continu ou alternatif, est appliqué au système. La réponse thermique et mécanique du système est alors obtenue. Les conclusions de cette étude permettent d'une part de mieux caractériser le comportement électro thermomécanique des fils de bonding et de mieux comprendre l'origine des modes de défaillance de cette technologie d'interconnexion. D'autre part, une démarche d'utilisation des modèles et outils logiciels multi physiques pour une simulation électro thermomécanique est présentéeThe trend in the field of railway transport is to integrate increasingly powerful power modules in smaller volumes. This is problematic, especially in terms of reliability: during their cycles of operation, the semiconductor switches and their immediate environment are subject to tougher electro-thermo-mechanical stresses. This can lead to their destruction and then, to the failure of the energy conversion function. The main goal of this work is to describe the models and multi-physics simulation tools to characterize these stresses. We chose as a case study the connection wire called wire bonding . These wires are, indeed, considered one of the weaknesses of the life time of the power module used in embedded systems, particularly in railway applications. In this multi-physics context, we have developed numerical, finite elements, analytical, 3D or 1D models to determine the thermo-mechanical stresses during the current flow through the wires. Thanks to the models described and the simulation results presented, we characterize the behavior of the wire for an electrical, thermal, magnetic or mechanical point of view. More precisely, the electro-magnetic, electro-thermal, electro-mechanical or thermo-mechanical interactions between models and between simulation tools are discussed. The results are compared to thermal and displacement measurements. They are realized thanks to experimental prototypes. The type of solicitation is called active. A system of direct or alternating current is applied to the system. The thermal and mechanical response of the system is obtained. The conclusions of this study allow, on the one hand, characterizing the electro thermo-mechanical behavior of wires bonding and understanding the origin of the failure modes of this technology. On the other hand, a way of using models and multi-physics software tools for an electro thermo-mechanical simulation is presentedTOULOUSE-INP (315552154) / SudocSudocFranceF

In-situ health monitoring of IGBT power modules in EV applications

Power electronics are an enabling technology and play a critical role in the establishment of an environmentally-friendly and sustainable low carbon economy. The electrification of passenger vehicles is one way of achieving this goal. It is well acknowledged that Electric vehicles (EVs) have inherent advantages over the conventional internal combustion engine (ICE) vehicles owing to the absence of emissions, high efficiency, and quiet and smooth operation. Over the last 20 years, EVs have improved significantly in their system integration, dynamic performance and cost. It has attracted much attention in research communities as well as in the market. In 2011 electric vehicle sales were estimated to reach about 20,000 units worldwide, increasing to more than 500,000 units by 2015 and 1.3 million by 2020 which accounts for 1.8 per cent of the total number of passenger vehicles expected to be sold that year. In general, electric vehicles use electric motors for traction drive, power converters for energy transfer and control, and batteries, fuel cells, ultracapacitors, or flywheels for energy storage. These are the core elements of the electric power drive train and thus are desired to provide high reliability over the lifetime of the vehicle. One of the vulnerable components in an electric power drive train is the IGBT switching devices in an inverter. During the operation, IGBT power modules will experience high mechanical and thermal stresses which lead to bond wire lift-off and solder joint fatigue faults. Theses stresses can lead to malfunctions of the IGBT power modules. A short-circuit or open-circuit in any of the power modules may result in an instantaneous loss of traction power, which is dangerous for the driver and other road users. These reliability issues are very complex in their nature and demand for the development of analytical models and experimental validation. This work is set out to develop an online measurement technique for health monitoring of IGBT and freewheeling diodes inside the power modules. The technique can provide an early warning prior to a power device failure. Bond wire lift-off and solder fatigue are the two most frequently occurred faults in power electronic modules. The former increases the forward voltage drop across the terminals of the power device while the latter increase the thermal resistance of the solder layers. As a result, bond wire lift-off can be detected by a highly sensitive and fast operating in-situ monitoring circuit. Solder joint fatigue is detected by measuring the thermal impedance of the power modules. This thesis focuses on the design and optimisation of the in-situ health monitoring circuit in an attempt to reducing noise, temperature variations and measurement uncertainties. Experimental work is carried out on a set of various IGBT power modules that have been modified to account for different testing requirements. Then the lifetime of the power module can be estimated on this basis. The proposed health monitoring system can be integrated into the existing IGBT driver circuits and can also be applied to other applications such as industrial drives, aerospace and renewable energy.EThOS - Electronic Theses Online ServiceORSSchool of EEEGBUnited Kingdo

In-situ health monitoring of IGBT power modules in EV applications

Power electronics are an enabling technology and play a critical role in the establishment of an environmentally-friendly and sustainable low carbon economy. The electrification of passenger vehicles is one way of achieving this goal. It is well acknowledged that Electric vehicles (EVs) have inherent advantages over the conventional internal combustion engine (ICE) vehicles owing to the absence of emissions, high efficiency, and quiet and smooth operation. Over the last 20 years, EVs have improved significantly in their system integration, dynamic performance and cost. It has attracted much attention in research communities as well as in the market. In 2011 electric vehicle sales were estimated to reach about 20,000 units worldwide, increasing to more than 500,000 units by 2015 and 1.3 million by 2020 which accounts for 1.8 per cent of the total number of passenger vehicles expected to be sold that year. In general, electric vehicles use electric motors for traction drive, power converters for energy transfer and control, and batteries, fuel cells, ultracapacitors, or flywheels for energy storage. These are the core elements of the electric power drive train and thus are desired to provide high reliability over the lifetime of the vehicle. One of the vulnerable components in an electric power drive train is the IGBT switching devices in an inverter. During the operation, IGBT power modules will experience high mechanical and thermal stresses which lead to bond wire lift-off and solder joint fatigue faults. Theses stresses can lead to malfunctions of the IGBT power modules. A short-circuit or open-circuit in any of the power modules may result in an instantaneous loss of traction power, which is dangerous for the driver and other road users. These reliability issues are very complex in their nature and demand for the development of analytical models and experimental validation. This work is set out to develop an online measurement technique for health monitoring of IGBT and freewheeling diodes inside the power modules. The technique can provide an early warning prior to a power device failure. Bond wire lift-off and solder fatigue are the two most frequently occurred faults in power electronic modules. The former increases the forward voltage drop across the terminals of the power device while the latter increase the thermal resistance of the solder layers. As a result, bond wire lift-off can be detected by a highly sensitive and fast operating in-situ monitoring circuit. Solder joint fatigue is detected by measuring the thermal impedance of the power modules. This thesis focuses on the design and optimisation of the in-situ health monitoring circuit in an attempt to reducing noise, temperature variations and measurement uncertainties. Experimental work is carried out on a set of various IGBT power modules that have been modified to account for different testing requirements. Then the lifetime of the power module can be estimated on this basis. The proposed health monitoring system can be integrated into the existing IGBT driver circuits and can also be applied to other applications such as industrial drives, aerospace and renewable energy.EThOS - Electronic Theses Online ServiceORSSchool of EEEGBUnited Kingdo

Contribution à l'amélioration de la fiabilité des modules IGBT utilisés en environnement aéronautique

L’augmentation de la puissance électrique consommée à bord des avions a récemment conduit à introduire des convertisseurs électroniques de puissance à base d'interrupteurs à IGBT dans de nombreuses applications aéronautiques. L'utilisation de ces interrupteurs diffère de leurs emplois traditionnels dans les domaines du ferroviaire ou de l'automobile. En effet, les sollicitations environnementales ainsi que les cycles de commandes électriques sont différents de ceux rencontrés jusqu’alors, ce qui amène à remettre en cause les résultats actuels au sujet de la durée de vie et de la fiabilité de ces interrupteurs. Face à ces interrogations, les sociétés THALES et Hispano-Suiza se sont associées au sein du programme de l’avion plus électrique MODERNE (MODular ElectRical NEtwork) initié par Airbus, en vue de développer des solutions à haut niveau de fiabilité pour des applications aéronautiques sévères. C’est dans ce contexte que prennent place les présents travaux, dont les objectifs sont dans un premier temps de proposer de nouvelles architectures de modules susceptibles de présenter de meilleures performances d’intégration, et dans un second temps d’en étudier la fiabilité. Pour répondre à ces questions, un état de l'art des technologies utilisables a été mené. La confrontation de ses technologies aux contraintes et recommandations aéronautiques a conduit au choix de deux approches d'assemblage, proposées avec un jeu de matériaux sélectionnés pour leurs propriétés physiques et en conformité avec les réglementations sur l’utilisation de matériaux polluants. À l'issue d'une analyse de défaillances, différents développements ont été conduits afin de modéliser et caractériser le comportement thermique, mécanique puis à défaillance des modules. Des modèles Éléments Finis de structures représentatives des solutions proposées ont alors été mis au point et exploités pour l'élaboration de règles de conception, sur la base de plans d'expériences couplés à de la simulation numériques. Les informations générées ont servi à la conception de trois prototypes destinés à des applications différentes. Les performances de ces prototypes ont été évaluées, notamment leurs fiabilités obtenues par des calculs mécano-fiabilistes ayant permis l'optimisation de la conception des différents modules. ABSTRACT : Within the framework of the electric plane programs, the aircraft industry is facing higher demands of electric power, fact which involves an increasing use of IGBT modules in aeronautical power converters. Although such modules have been well studied and known in railway and the automotive domains, they will be subjected to stresses and operational cycles specific to the aeronautical environment. Consequently, this requires manufacturers to answer some questions about their lifetime and reliability issues. Faced with these questions, THALES and Hispano-Suiza have associated in the more electric aircraft project launched by Airbus (MODERNE - MODular ElectRical NEtwork), with the aim of developing high reliability solutions for harsh aeronautic applications. This work takes place in this context, with the objectives of proposing power modules architectures likely to exhibit better performances and integration level, and then study the reliability of different prototypes. To answer these questions, technological studies of the possible packaging and connecting solutions, faced with aeronautical stresses and requirements led to the choice of two basic assembling approaches. A set of materials selected for their physical properties and their compliance with polluting materials regulations was also proposed. The potential failure modes of these solutions were pointed out and taken into account within experimental and numerical developments, to model and characterize the thermal, mechanical and failure behaviour of the modules. Then, different Finite Element models representative of the proposed technologies structures were developed and investigated for defining design rules on the basis of Designs of Experiments. The whole knowledge generated by the simulations was used to design three prototypes of IGBT module for different applications. The performance of these prototypes have been evaluated and compared to the requirements, including their reliability obtained by mechanical calculations coupled with probabilistic methods which led to their optimization