Progress on optimization of the solar cell fabrication process by impurity-to-efficiency predictive simulator

To optimize the last high temperature step of a standard solar cell fabrication process (the contact cofiring step), the aluminium gettering is incorporated in the Impurity-to-Efficiency simulation tool, so that it models the phosphorus and aluminium co-gettering effect on iron impurities. The impact of iron on the cell efficiency will depend on the balance between precipitate dissolution and gettering. Gettering efficiency is similar in a wide range of peak temperatures (600-850 ºC), so that this peak temperature can be optimized favoring other parameters (e.g. ohmic contact). An industrial co-firing step can enhance the co-gettering effect by adding a temperature plateau after the peak of temperature. For highly contaminated materials, a short plateau (menor que 2 min) at low temperature (600 ºC) is shown to reduce the dissolved iron.

Co-simulation Methodologies for Hybrid and Electric Vehicle Dynamics

In recent decades, full electric and hybrid electric vehicles have emerged as an alternative to conventional cars due to a range of factors, including environmental and economic aspects. These vehicles are the result of considerable efforts to seek ways of reducing the use of fossil fuel for vehicle propulsion. Sophisticated technologies such as hybrid and electric powertrains require careful study and optimization. Mathematical models play a key role at this point. Currently, many advanced mathematical analysis tools, as well as computer applications have been built for vehicle simulation purposes. Given the great interest of hybrid and electric powertrains, along with the increasing importance of reliable computer-based models, the author decided to integrate both aspects in the research purpose of this work. Furthermore, this is one of the first final degree projects held at the ETSII (Higher Technical School of Industrial Engineers) that covers the study of hybrid and electric propulsion systems. The present project is based on MBS3D 2.0, a specialized software for the dynamic simulation of multibody systems developed at the UPM Institute of Automobile Research (INSIA). Automobiles are a clear example of complex multibody systems, which are present in nearly every field of engineering. The work presented here benefits from the availability of MBS3D software. This program has proven to be a very efficient tool, with a highly developed underlying mathematical formulation. On this basis, the focus of this project is the extension of MBS3D features in order to be able to perform dynamic simulations of hybrid and electric vehicle models. This requires the joint simulation of the mechanical model of the vehicle, together with the model of the hybrid or electric powertrain. These sub-models belong to completely different physical domains. In fact the powertrain consists of energy storage systems, electrical machines and power electronics, connected to purely mechanical components (wheels, suspension, transmission, clutch…). The challenge today is to create a global vehicle model that is valid for computer simulation. Therefore, the main goal of this project is to apply co-simulation methodologies to a comprehensive model of an electric vehicle, where sub-models from different areas of engineering are coupled. The created electric vehicle (EV) model consists of a separately excited DC electric motor, a Li-ion battery pack, a DC/DC chopper converter and a multibody vehicle model. Co-simulation techniques allow car designers to simulate complex vehicle architectures and behaviors, which are usually difficult to implement in a real environment due to safety and/or economic reasons. In addition, multi-domain computational models help to detect the effects of different driving patterns and parameters and improve the models in a fast and effective way. Automotive designers can greatly benefit from a multidisciplinary approach of new hybrid and electric vehicles. In this case, the global electric vehicle model includes an electrical subsystem and a mechanical subsystem. The electrical subsystem consists of three basic components: electric motor, battery pack and power converter. A modular representation is used for building the dynamic model of the vehicle drivetrain. This means that every component of the drivetrain (submodule) is modeled separately and has its own general dynamic model, with clearly defined inputs and outputs. Then, all the particular submodules are assembled according to the drivetrain configuration and, in this way, the power flow across the components is completely determined. Dynamic models of electrical components are often based on equivalent circuits, where Kirchhoff’s voltage and current laws are applied to draw the algebraic and differential equations. Here, Randles circuit is used for dynamic modeling of the battery and the electric motor is modeled through the analysis of the equivalent circuit of a separately excited DC motor, where the power converter is included. The mechanical subsystem is defined by MBS3D equations. These equations consider the position, velocity and acceleration of all the bodies comprising the vehicle multibody system. MBS3D 2.0 is entirely written in MATLAB and the structure of the program has been thoroughly studied and understood by the author. MBS3D software is adapted according to the requirements of the applied co-simulation method. Some of the core functions are modified, such as integrator and graphics, and several auxiliary functions are added in order to compute the mathematical model of the electrical components. By coupling and co-simulating both subsystems, it is possible to evaluate the dynamic interaction among all the components of the drivetrain. ‘Tight-coupling’ method is used to cosimulate the sub-models. This approach integrates all subsystems simultaneously and the results of the integration are exchanged by function-call. This means that the integration is done jointly for the mechanical and the electrical subsystem, under a single integrator and then, the speed of integration is determined by the slower subsystem. Simulations are then used to show the performance of the developed EV model. However, this project focuses more on the validation of the computational and mathematical tool for electric and hybrid vehicle simulation. For this purpose, a detailed study and comparison of different integrators within the MATLAB environment is done. Consequently, the main efforts are directed towards the implementation of co-simulation techniques in MBS3D software. In this regard, it is not intended to create an extremely precise EV model in terms of real vehicle performance, although an acceptable level of accuracy is achieved. The gap between the EV model and the real system is filled, in a way, by introducing the gas and brake pedals input, which reflects the actual driver behavior. This input is included directly in the differential equations of the model, and determines the amount of current provided to the electric motor. For a separately excited DC motor, the rotor current is proportional to the traction torque delivered to the car wheels. Therefore, as it occurs in the case of real vehicle models, the propulsion torque in the mathematical model is controlled through acceleration and brake pedal commands. The designed transmission system also includes a reduction gear that adapts the torque coming for the motor drive and transfers it. The main contribution of this project is, therefore, the implementation of a new calculation path for the wheel torques, based on performance characteristics and outputs of the electric powertrain model. Originally, the wheel traction and braking torques were input to MBS3D through a vector directly computed by the user in a MATLAB script. Now, they are calculated as a function of the motor current which, in turn, depends on the current provided by the battery pack across the DC/DC chopper converter. The motor and battery currents and voltages are the solutions of the electrical ODE (Ordinary Differential Equation) system coupled to the multibody system. Simultaneously, the outputs of MBS3D model are the position, velocity and acceleration of the vehicle at all times. The motor shaft speed is computed from the output vehicle speed considering the wheel radius, the gear reduction ratio and the transmission efficiency. This motor shaft speed, somehow available from MBS3D model, is then introduced in the differential equations corresponding to the electrical subsystem. In this way, MBS3D and the electrical powertrain model are interconnected and both subsystems exchange values resulting as expected with tight-coupling approach.When programming mathematical models of complex systems, code optimization is a key step in the process. A way to improve the overall performance of the integration, making use of C/C++ as an alternative programming language, is described and implemented. Although this entails a higher computational burden, it leads to important advantages regarding cosimulation speed and stability. In order to do this, it is necessary to integrate MATLAB with another integrated development environment (IDE), where C/C++ code can be generated and executed. In this project, C/C++ files are programmed in Microsoft Visual Studio and the interface between both IDEs is created by building C/C++ MEX file functions. These programs contain functions or subroutines that can be dynamically linked and executed from MATLAB. This process achieves reductions in simulation time up to two orders of magnitude. The tests performed with different integrators, also reveal the stiff character of the differential equations corresponding to the electrical subsystem, and allow the improvement of the cosimulation process. When varying the parameters of the integration and/or the initial conditions of the problem, the solutions of the system of equations show better dynamic response and stability, depending on the integrator used. Several integrators, with variable and non-variable step-size, and for stiff and non-stiff problems are applied to the coupled ODE system. Then, the results are analyzed, compared and discussed. From all the above, the project can be divided into four main parts: 1. Creation of the equation-based electric vehicle model; 2. Programming, simulation and adjustment of the electric vehicle model; 3. Application of co-simulation methodologies to MBS3D and the electric powertrain subsystem; and 4. Code optimization and study of different integrators. Additionally, in order to deeply understand the context of the project, the first chapters include an introduction to basic vehicle dynamics, current classification of hybrid and electric vehicles and an explanation of the involved technologies such as brake energy regeneration, electric and non-electric propulsion systems for EVs and HEVs (hybrid electric vehicles) and their control strategies. Later, the problem of dynamic modeling of hybrid and electric vehicles is discussed. The integrated development environment and the simulation tool are also briefly described. The core chapters include an explanation of the major co-simulation methodologies and how they have been programmed and applied to the electric powertrain model together with the multibody system dynamic model. Finally, the last chapters summarize the main results and conclusions of the project and propose further research topics. In conclusion, co-simulation methodologies are applicable within the integrated development environments MATLAB and Visual Studio, and the simulation tool MBS3D 2.0, where equation-based models of multidisciplinary subsystems, consisting of mechanical and electrical components, are coupled and integrated in a very efficient way.

Defect engineering during the contact co-firing step in an industrial belt furnace

This work implements an optimization of the phosphorus gettering effect during the contact co-firing step by means of both simulations and experiments in an industrial belt furnace. An optimized temperature profile, named ‘extended co-firing step’, is presented. Simulations show that the effect of the short annealing on the final interstitial iron concentration depends strongly on the initial contamination level of the material and that the ‘extended co-firing’ temperature profile can enhance the gettering effect within a small additional time. Experimental results using sister wafers from the same multicrystalline silicon ingot confirm these trends and show the potential of this new defect engineering tool to improve the solar cell efficiency.

OMNIWORKS: Omnidirectional vision for human-UAV co-working

The OMNIWORKS project objective is to develop an autonomous and modular aerial inspection system for an off-shore meteorological mast up to 90m in length. The UAV was equipped with an omni-directional camera and vertical take-off/landing capabilities that should be simple enough to operate as to not need the interventions of a professional pilot under challenging situations. Therefore the tests included different aspects used to evaluate both the technical performance of the UAV behavior as well as the operators? point of view.

Evaluación de los co-beneficios sobre el desarrollo sostenible y la reducción de la pobreza de proyectos de mitigación del cambio climático en Brasil

El cambio climático y los diferentes aspectos del concepto de “desarrollo” están intrínsecamente interconectados. Por un lado, el desarrollo económico de nuestras sociedades ha contribuido a un aumento insostenible de las emisiones de gases de efecto invernadero, las cuales están desestabilizando el sistema climático global, generando al mismo tiempo una distribución desigual de la capacidad de las personas para hacer frente a estos cambios. Por otro lado, en la actualidad existe un amplio consenso sobre que el cambio climático impacta directamente y de manera negativa sobre el denominando desarrollo sostenible. De igual manera, cada vez existe un mayor consenso de que el cambio climático va a desafiar sustancialmente nuestra capacidad de erradicar la pobreza a medio y largo plazo. Ante esta realidad, no cabe duda de que las estrategias de adaptación son esenciales para mantener el desarrollo. Es por esto que hasta el momento, los mayores esfuerzos realizados por unir las agendas globales de la lucha contra la pobreza y del cambio climático se han dado en el entorno de la adaptación al cambio climático. Sin embargo, cada vez son más los actores que defienden, desde distintos escenarios, que existen sinergias entre la mitigación de emisiones y la mejora de las condiciones de vida de las poblaciones más vulnerables, favoreciendo así un “desarrollo sostenible” sin disminuir los recursos financieros destinados a la adaptación. Para hacer efectivo este potencial, es imprescindible identificar diseños de estrategias de mitigación que incrementen los resultados de desarrollo, contribuyendo al desarrollo sostenible al mismo tiempo que a reducir la pobreza. En este contexto se sitúa el objetivo principal de esta investigación, consistente en analizar los co-beneficios locales, para el desarrollo sostenible y la reducción la pobreza, de proyectos de mitigación del cambio climático que se implementan en Brasil. Por co-beneficios se entienden, en el lenguaje de las discusiones internacionales de cambio climático, aquellos beneficios que van más allá de la reducción de emisiones de Gases de Efecto Invernadero (GEI) intrínsecas por definición a los proyectos de mitigación. Los proyectos de mitigación más relevantes hasta el momento bajo el paraguas de la Convención Marco de las Naciones Unidas para el Cambio Climático (CMNUCC), son los denominados Mecanismos de Desarrollo Limpio (MDL) del Protocolo de Kioto. Sin embargo, existen alternativas de proyectos de mitigación (tales como los denominados “estándares adicionales” a los MDL de los Mercados Voluntarios de Carbono y las Tecnologías Sociales), que también serán tenidos en cuenta en el marco de este estudio. La elección del tema se justifica por la relevancia del mismo en un momento histórico en el que se está decidiendo el futuro del régimen climático a partir del año 2020. Aunque en el momento de redactar este documento, todavía no se ha acordado la forma que tendrán los futuros instrumentos de mitigación, sí que se sabe que los co-beneficios de estos instrumentos serán tan importantes, o incluso más, que las reducciones de GEI que generan. Esto se debe, principalmente, a las presiones realizadas en las negociaciones climáticas por parte de los países menos desarrollados, para los cuales el mayor incentivo de formar parte de dichas negociaciones se basa principalmente en estos potenciales co-beneficios. Los resultados de la tesis se estructuran alrededor de tres preguntas de investigación: ¿cómo están contribuyendo los MDL implementados en Brasil a generar co-beneficios que fomenten el desarrollo sostenible y reduzcan la pobreza?; ¿existen proyectos de mitigación en Brasil que por tener compromisos más exigentes en cuanto a su contribución al desarrollo sostenible y/o la reducción de la pobreza que los MDL estén siendo más eficientes que estos en relación a los co-beneficios que generan?; y ¿qué características de los proyectos de mitigación pueden resultar críticas para potenciar sus co-beneficios en las comunidades en las que se implementan? Para dar respuesta a estas preguntas, se ha desarrollado durante cuatro años una labor de investigación estructurada en varias fases y en la que se combinan diversas metodologías, que abarcan desde el desarrollo de un modelo de análisis de cobeneficios, hasta la aplicación del mismo tanto a nivel documental sobre 194 documentos de diseño de proyecto (denominado análisis ex-ante), como a través de 20 casos de estudio (denominado análisis ex-post). Con la realización de esta investigación, se ha confirmado que los requisitos existentes hasta el momento para registrar un proyecto como MDL bajo la CMNUCC no favorecen sustancialmente la generación de co-beneficios locales para las comunidades en las que se implementan. Adicionalmente, se han identificado prácticas y factores, que vinculadas a las actividades intrínsecas de los proyectos de mitigación, son efectivas para incrementar sus co-beneficios. Estas prácticas y factores podrán ser tenidas en cuenta tanto para mejorar los requisitos de los actuales proyectos MDL, como para apoyar la definición de los nuevos instrumentos climáticos. ABSTRACT Climate change and development are inextricably linked. On the one hand, the economic development of our societies has contributed to the unsustainable increase of Green House Gases emissions, which are destabilizing the global climate system while fostering an unequal distribution of people´s ability to cope with these changes. On the other hand, there is now a consensus that climate change directly impacts the so-called sustainable development. Likely, there is a growing agreement that climate change will substantially threaten our capacity to eradicate poverty in the medium and long term. Given this reality, there is no doubt that adaptation strategies are essentials to keep development. This is why, to date, much of the focus on poverty in the context of climate change has been on adaptation However, without diverting resources from adaptation, there may exist the potential to synergize efforts to mitigate emissions, contribute to sustainable development and reduce poverty. To fulfil this potential, it is key identifying how mitigation strategies can also support sustainable development and reduce poverty. In this context, the main purpose of this investigation is to explore the co-benefits, for sustainable development and for poverty reduction, of climate change mitigation projects being implemented in Brazil. In recent years the term co-benefits, has been used by policy makers and academics to refer the potentially large and diverse range of collateral benefits that can be associated with climate change mitigation policies in addition to the direct avoided climate impact benefits. The most relevant mitigation projects developed during the last years under the United Nations Framework Convention on Climate Change (UNFCCC) are the so-called Clean Development Mechanisms (CDM) of the Kyoto Protocol. Thus, this research will analyse this official mechanism. However, there are alternatives to the mitigation projects (such as the "add-on standards" of the Voluntary Carbon Markets, and the Social Technologies) that will also be assessed as part of the research. The selection of this research theme is justified because its relevance in a historic moment in which proposals for a future climate regime after 2020 are being negotiated. Although at the moment of writing this document, there is not a common understanding on the shape of the new mitigation instruments, there is a great agreement about the importance of the co-benefits of such instruments, which may be even more important for the Least Developed Countries that their expected greenhouse gases emissions reductions. The results of the thesis are structured around three research questions: how are the CDM projects being implemented in Brazil generating local co-benefits that foster sustainable development and poverty reduction?; are other mitigation projects in Brazil that due to their more stringent sustainable development and/o poverty reduction criteria, any more successful at delivering co-benefits than regular CDM projects?; and what are the distinguishing characteristics of mitigation projects that are successful at delivering co-benefits? To answer these research questions, during four years it has been developed a research work structured in several phases and combining various methodologies. Those methodologies cover from the development of a co-benefits assessment model, to the application of such model both to a desktop analysis of 194 project design documents, and to 20 case studies using field data based on site visits to the project sites. With the completion of this research, it has been confirmed that current requirements to register a CDM project under the UNFCCC not substantially favour co-benefits at the local level. In addition, some practices and factors enablers of co-benefits have been identified. These characteristics may be taken into consideration to improve the current CDM and to support the definition of the new international market mechanisms for climate mitigation.

Inscribir las trazas del pasado industrial en el futuro de la ciudad: la regeneración de Île de Nantes

El proyecto de Île de Nantes ha sido objeto de innumerables análisis y publicaciones desde que comenzó en 1999. Si bien la importancia del patrimonio industrial de la isla se ha señalado en varias ocasiones, e incluso la revista L?Archéologie industrielle en France dedicó a Nantes un número monográfico que tituló significativamente ?Nantes, un modèle??; los modos en que se establecieron los vínculos entre urbanismo y conservación del patrimonio industrial, no parecen haber sido suficientemente analizados. El objetivo de este artículo es, precisamente, estudiar el proyecto desde la perspectiva del patrimonio y su conservación

Determinación de propiedades de inflamabilidad de mezclas para co-combustión

La recuperación de energía a partir de biomasa y residuos no reciclables por la combustión está cobrando una notable importancia actualmente. Una de las técnicas más utilizadas para esta propuesta es la co-combustión de mezclas de residuos y biomasa. Con esta nueva tecnología, mezclas de diferentes materiales han aparecido en las instalaciones industriales y tienen que ser reconocidas como nuevos combustibles, debido a que a sus propiedades son aún desconocidas. Estas propiedades incluyen las energéticas, que son el objetivo del proceso de mezcla, y también las propiedades de inflamabilidad. Residuos y biomasa en forma de polvos tienen propiedades de ignición que se han de tener en cuenta a la hora de diseñar las medidas de prevención y protección en una instalación industrial. El objetivo principal de este estudio es determinar el riesgo de ignición de las mezclas de residuos / biomasa en capas y cómo, mediante la adición de diferentes cantidades de estos materiales, este riesgo puede cambiar. Para desarrollar este estudio, se utiliza la temperatura mínima de ignición en la capa. Tres muestras diferentes han sido analizadas, lodos con secado térmico de depuradora, paja de trigo y virutas de madera, Abstract Energy recovery from biomass and non-recyclable waste products by combustion has become important. One of the most used techniques for this proposal is the co-firing of waste and biomass mixtures, With this new technology, mixtures of different materials have appeared in the industrial facilities and they have to be treated as new fuels because their properties are unknown. Among this properties we include energetic properties that are the objective of the mixing process, and also the ignitability properties. Waste and biomass dusts have ignition properties that have to be taken into account in the design but also in the, prevention and protection process of an industrial facility.. The main objective of this research is to determine the risk of ignition of waste / biomass mixtures layers and how, by adding different quantities of these materials, this risk may vary. To develop this, the minimum ignition temperature on layer is used. Three different samples have been analysed, thermally dried sewage sludge, wheat straw and wood chips.

Passenger Exposure to Magnetic Fields due to the Batteries of an Electric Vehicle

In electric vehicles, passengers sit very close to an electric system of significant power. The high currents achieved in these vehicles mean that the passengers could be exposed to significant magnetic fields. One of the electric devices present in the power train are the batteries. In this paper, a methodology to evaluate the magnetic field created by these batteries is presented. First, the magnetic field generated by a single battery is analyzed using finite elements simulations. Results are compared to laboratory measurements, taken from a real battery, in order to validate the model. After this, the magnetic field created by a complete battery pack is estimated and results are discussed.

Analysis and Design Considerations of an Electric Vehicle Powertrain regarding Energy Efficiency and Magnetic Field Exposure

En esta tesis se analiza el sistema de tracción de un vehículo eléctrico de batería desde el punto de vista de la eficiencia energética y de la exposición a campos magnéticos por parte de los pasajeros (radiación electromagnética). Este estudio incluye tanto el sistema de almacenamiento de energía como la máquina eléctrica, junto con la electrónica de potencia y los sistemas de control asociados a ambos. Los análisis y los resultados presentados en este texto están basados en modelos matemáticos, simulaciones por ordenador y ensayos experimentales a escala de laboratorio. La investigación llevada a cabo durante esta tesis tuvo siempre un marcado enfoque industrial, a pesar de estar desarrollada en un entorno de considerable carácter universitario. Las líneas de investigación acometidas tuvieron como destinatario final al diseñador y al fabricante del vehículo, a pesar de lo cual algunos de los resultados obtenidos son preliminares y/o excesivamente académicos para resultar de interés industrial. En el ámbito de la eficiencia energética, esta tesis estudia sistemas híbridos de almacenamiento de energía basados en una combinación de baterías de litio y supercondensadores. Este tipo de sistemas son analizados desde el punto de vista de la eficiencia mediante modelos matemáticos y simulaciones, cuantificando el impacto de ésta en otros parámetros tales como el envejecimiento de las baterías. Respecto a la máquina eléctrica, el estudio se ha centrado en máquinas síncronas de imanes permanentes. El análisis de la eficiencia considera tanto el diseño de la máquina como la estrategia de control, dejando parcialmente de lado el inversor y la técnica de modulación (que son incluidos en el estudio como fuentes adicionales de pérdidas, pero no como potenciales fuentes de optimización de la eficiencia). En este sentido, tanto la topología del inversor (trifásico, basado en IGBTs) como la técnica de modulación (control de corriente en banda de histéresis) se establecen desde el principio. El segundo aspecto estudiado en esta tesis es la exposición a campos magnéticos por parte de los pasajeros. Este tema se enfoca desde un punto de vista predictivo, y no desde un punto de vista de diagnóstico, puesto que se ha desarrollado una metodología para estimar el campo magnético generado por los dispositivos de potencia de un vehículo eléctrico. Esta metodología ha sido validada mediante ensayos de laboratorio. Otros aspectos importantes de esta contribución, además de la metodología en sí misma, son las consecuencias que se derivan de ella (por ejemplo, recomendaciones de diseño) y la comprensión del problema proporcionada por esta. Las principales contribuciones de esta tesis se listan a continuación: una recopilación de modelos de pérdidas correspondientes a la mayoría de dispositivos de potencia presentes en un vehículo eléctrico de batería, una metodología para analizar el funcionamiento de un sistema híbrido de almacenamiento de energía para aplicaciones de tracción, una explicación de cómo ponderar energéticamente los puntos de operación par-velocidad de un vehículo eléctrico (de utilidad para evaluar el rendimiento de una máquina eléctrica, por ejemplo), una propuesta de incluir un convertidor DC-DC en el sistema de tracción para minimizar las pérdidas globales del accionamiento (a pesar de las nuevas pérdidas introducidas por el propio DC-DC), una breve comparación entre dos tipos distintos de algoritmos de minimización de pérdidas para máquinas síncronas de imanes permanentes, una metodología predictiva para estimar la exposición a campos magnéticos por parte de los pasajeros de un vehículo eléctrico (debida a los equipos de potencia), y finalmente algunas conclusiones y recomendaciones de diseño respecto a dicha exposición a campos magnéticos. ABSTRACT This dissertation analyzes the powertrain of a battery electric vehicle, focusing on energy efficiency and passenger exposure to electromagnetic fields (electromagnetic radiation). This study comprises the energy storage system as well as the electric machine, along with their associated power electronics and control systems. The analysis and conclusions presented in this dissertation are based on mathematical models, computer simulations and laboratory scale tests. The research performed during this thesis was intended to be of industrial nature, despite being developed in a university. In this sense, the work described in this document was carried out thinking of both the designer and the manufacturer of the vehicle. However, some of the results obtained lack industrial readiness, and therefore they remain utterly academic. Regarding energy efficiency, hybrid energy storage systems consisting in lithium batteries, supercapacitors and up to two DC-DC power converters are considered. These kind of systems are analyzed by means of mathematical models and simulations from the energy efficiency point of view, quantifying its impact on other relevant aspects such as battery aging. Concerning the electric machine, permanent magnet synchronous machines are studied in this work. The energy efficiency analysis comprises the machine design and the control strategy, while the inverter and its modulation technique are taken into account but only as sources of further power losses, and not as potential sources for further efficiency optimization. In this sense, both the inverter topology (3-phase IGBT-based inverter) and the switching technique (hysteresis current control) are fixed from the beginning. The second aspect studied in this work is passenger exposure to magnetic fields. This topic is approached from the prediction point of view, rather than from the diagnosis point of view. In other words, a methodology to estimate the magnetic field generated by the power devices of an electric vehicle is proposed and analyzed in this dissertation. This methodology has been validated by laboratory tests. The most important aspects of this contribution, apart from the methodology itself, are the consequences (for instance, design guidelines) and the understanding of the magnetic radiation issue provided by it. The main contributions of this dissertation are listed next: a compilation of loss models for most of the power devices found in a battery electric vehicle powertrain, a simulation-based methodology to analyze hybrid energy storage performance in traction applications, an explanation of how to assign energy-based weights to different operating points in traction drives (useful when assessing electrical machine performance, for instance), a proposal to include one DC-DC converter in electric powertrains to minimize overall power losses in the system (despite the new losses added by the DC-DC), a brief comparison between two kinds of loss-minimization algorithms for permanent magnet synchronous machines in terms of adaptability and energy efficiency, a predictive methodology to estimate passenger magnetic field exposure due to power devices in an electric vehicle, and finally some useful conclusions and design guidelines concerning magnetic field exposure.