L'amélioration de l'efficacité énergétique est devenue aujourd'hui une nécessité dans tous les domaines techniques. La réduction de la consommation, et donc du bilan carbone, est placée parmi les priorités mondiales tel que le paquet énergie-climat 2020 de l'Union Européenne.Les systèmes ferroviaires font partie des plus grands consommateurs d'énergie. Des solutions électriques sont développées pour réduire les pertes dans ces systèmes, optimiser la consommation et donc réduire la facture énergétique globale. Étant donné la diversité de ces systèmes, deux catégories principales sont considérées. La première regroupe les lignes urbaines caractérisées par une électrification en mode DC et un trafic relativement dense. Dans ce cas, l'énergie de freinage brûlée dans les rhéostats des trains constitue une perte considérable. La solution proposée consiste à récupérer cette énergie à l'aide d'un DC micro-grid installé dans une station passager. Elle permettra une interaction avec son environnement non-ferroviaire comme par exemple réutiliser cette énergie pour charger des bus électriques hybrides stationnant à proximité. Ce micro-grid contient un premier convertisseur DC/DC qui récupère l’excès d'énergie de freinage d'un train et l'injecte dans un DC busbar. Un deuxième convertisseur DC/DC va ensuite la stocker dans un système de stockage hybride pour que le bus électrique puisse se charger une fois branché au DC busbar. Le micro-grid est relié au réseau par un onduleur réversible AC/DC de faible puissance. L'ensemble est géré localement par un système gestion de puissance. Une évaluation énergétique montre que cette solution est intéressante lorsqu’un investissement, station de charge, est nécessaire pour charger les bus. En plus, dans le cas du DC micro-grid, aucun contrat avec le fournisseur d’électricité n’est nécessaire. La stabilité du système est aussi étudiée et une commande de stabilisation, le backstepping, est appliquée. Ce nouveau concept d’une future station intelligente permettra au système ferroviaire de communiquer avec son environnement qui est en pleine évolution.La deuxième catégorie est constituée par les lignes régionales et les lignes à grandes vitesses fonctionnant en mode AC. Contrairement au cas précédent, l’excès d’énergie de freinage est renvoyé à travers les sous-stations d’alimentation. Par conséquence, une deuxième solution propose la réduction de la consommation totale par l’optimisation du profile de vitesse de chaque train et la synchronisation de la grille horaire. Ceci est réalisé à l’aide d’un algorithme d’évolution différentielle. Chaque profile de vitesse est découpé en zones auxquelles sont attribuées des paramètres de conduite. L'optimisation de ces derniers permet de générer un nouveau profile de conduite optimal. Les résultats montrent la possibilité de faire des économies d’énergie tout en respectant la ponctualité des trains. / Increasing energy efficiency is nowadays a requirement in all technical fields. The reduction of global consumption, thus carbon footprint, has become the world's priority, as for example, the climate and energy package of the European Union.Railways' share of energy consumption is one of the highest. Electrical solutions are developed in order to reduce these systems' losses, optimize their consumption and reduce global energy bill. Given their diversity, two main categories are considered in this study. The first one consists of urban lines that are characterized by a DC electrification and a relatively dense traffic. In this case, braking energy burned in trains' rheostats represents the main share of losses. The proposed solution is to recuperate this energy using a DC micro-grid implemented in a passengers' station. It allows an interaction with the non-railway electrical environment, for example, re-using this energy in charging electric hybrid buses parked nearby. The excess of braking energy is recuperated using a DC/DC converter and injected into a DC busbar. A second DC/DC converter will store it in a hybrid storage system. It will then serve to charge the buses connected to the DC busbar. The micro-grid is also connected to the grid using a low power AC/DC converter. A power management system ensures optimizing power flow between different components. An energy evaluation showed that this solution is a good Investment especially because no contract is needed with the energy provider. The system's stability is studied and a stabilizing command, the backstepping, is applied. This new smart station allows railways to communicate, energetically, with its evolving environment.The second category is suburban and high speed lines that are AC electrified. Contrarily to the previous case, braking energy is reinjected to the upper grid through substations. Therefore, a second solution is to reduce global energy consumption by optimizing trains' speed profiles and timetable's synchronization. It is done using a differential evolution algorithm. Each speed profile is divided into zones to which are associated driving parameters. The optimization of the latter allowed generating new optimal speed profiles and a less-consuming timetable. Simulation results showed that it is possible to make important energy savings while respecting train's punctuality.

Esta tese de doutorado visa o estudo e o desenvolvimento de topologias e técnicas de controle para a integração de fontes alternativas tais como, solar e eólica acopladas a um barramento comum em corrente continua (CC) e conectá-las à rede de distribuição. O sistema contará também com elementos armazenadores como bancos de baterias e ultracapacitores, formando assim uma estrutura híbrida de armazenamento. Algoritmos de gerenciamento de energia serão implementados para que o perfil de injeção de potência na rede seja suave, eliminando as oscilações que são criadas, naturalmente, por fontes dependentes de fatores climáticos. Como consequência, os sistemas formados por fontes alternativas podem se tornar confiáveis e previsíveis, melhorando a capacidade de planejamento em um cenário cujos sistemas apresentem uma participação elevada na matriz energética. Duas metodologias de gerenciamento de energia são executadas neste trabalho, na primeira o ultracapacitor é gerenciado de modo a permitir a transferência de potência constante para a rede de distribuição em intervalos da ordem de minutos. A segunda estratégia se baseia no uso de banco de baterias combinado com ultracapacitores, formando uma estrutura híbrida de armazenamento. Nessa estrutura de gerenciamento, os armazenadores se comunicam entre si de forma a realizar um compartilhamento e filtragem de energia, fazendo com que transitórios de potência não sejam transmitidos para a rede de distribuição. Nesta estratégia, as baterias são responsáveis pelo fornecimento/absorção da potência média enquanto os ultracapacitores se encarregam dos transitórios. No segundo instante outras duas metodologias de divisão de carga são propostas para microrredes híbridas, contudo são baseadas em estratégias descentralizadas, ou seja, os armazenadores não se comunicam entre si para realizar o compartilhamento. Resultados experimentais e simulações irão comprovar a efetividade das metodologias de gerenciamento propostas. / This Ph.D. dissertation aims the study and development of topologies and control techniques to integrate various alternative sources such as solar and wind, coupled to a direct current (DC) common bus and connect them to the distribution grid. Storage devices such as battery banks and ultracapacitors will form a hybrid storage structure that is responsible for the power supplying in periods in which the sources are unable (times of the day in which the light incidence is low or when the wind amount is scarce). Power management algorithms will be implemented so the alternative sources and storage devices exchange energy, in order to make smoother the power injection profile in the grid, eliminating the fluctuations that are created naturally by alternative sources. With a smooth power profile, energy management systems based on alternative sources may become more reliable and predictable, improving planning capacity in a scenario in which the renewable energy sources have a high penetration in the energy matrix. To obtain such a result, two power management methodologies are executed; the first one is based on ultracapacitors and aims to deliver constant power to the distribution network, even when the power production is zero. However, this technique allows constant power just for a few minutes, once the ultracapacitor capacity is limited. The second strategy is based on the bank of batteries combined with ultracapacitors, forming the hybrid storage system. In this management structure, the storage devices communicate with each other in order to perform a power sharing, resulting in a filtrated power profile delivered to the distribution network. In this strategy, the batteries are responsible to providing average power while ultracapacitors are in-charge of the transient power, sparing the batteries from supplying power peaks. In a second moment, two other load sharing methodologies are proposed for hybrid systems, but are based on decentralized techniques, i.e. storage devices do not communicate with each other to make the power sharing. Experimental and simulated results will prove the effectiveness of the control strategies and management methodologies.

Esta tese de doutorado visa o estudo e o desenvolvimento de topologias e técnicas de controle para a integração de fontes alternativas tais como, solar e eólica acopladas a um barramento comum em corrente continua (CC) e conectá-las à rede de distribuição. O sistema contará também com elementos armazenadores como bancos de baterias e ultracapacitores, formando assim uma estrutura híbrida de armazenamento. Algoritmos de gerenciamento de energia serão implementados para que o perfil de injeção de potência na rede seja suave, eliminando as oscilações que são criadas, naturalmente, por fontes dependentes de fatores climáticos. Como consequência, os sistemas formados por fontes alternativas podem se tornar confiáveis e previsíveis, melhorando a capacidade de planejamento em um cenário cujos sistemas apresentem uma participação elevada na matriz energética. Duas metodologias de gerenciamento de energia são executadas neste trabalho, na primeira o ultracapacitor é gerenciado de modo a permitir a transferência de potência constante para a rede de distribuição em intervalos da ordem de minutos. A segunda estratégia se baseia no uso de banco de baterias combinado com ultracapacitores, formando uma estrutura híbrida de armazenamento. Nessa estrutura de gerenciamento, os armazenadores se comunicam entre si de forma a realizar um compartilhamento e filtragem de energia, fazendo com que transitórios de potência não sejam transmitidos para a rede de distribuição. Nesta estratégia, as baterias são responsáveis pelo fornecimento/absorção da potência média enquanto os ultracapacitores se encarregam dos transitórios. No segundo instante outras duas metodologias de divisão de carga são propostas para microrredes híbridas, contudo são baseadas em estratégias descentralizadas, ou seja, os armazenadores não se comunicam entre si para realizar o compartilhamento. Resultados experimentais e simulações irão comprovar a efetividade das metodologias de gerenciamento propostas. / This Ph.D. dissertation aims the study and development of topologies and control techniques to integrate various alternative sources such as solar and wind, coupled to a direct current (DC) common bus and connect them to the distribution grid. Storage devices such as battery banks and ultracapacitors will form a hybrid storage structure that is responsible for the power supplying in periods in which the sources are unable (times of the day in which the light incidence is low or when the wind amount is scarce). Power management algorithms will be implemented so the alternative sources and storage devices exchange energy, in order to make smoother the power injection profile in the grid, eliminating the fluctuations that are created naturally by alternative sources. With a smooth power profile, energy management systems based on alternative sources may become more reliable and predictable, improving planning capacity in a scenario in which the renewable energy sources have a high penetration in the energy matrix. To obtain such a result, two power management methodologies are executed; the first one is based on ultracapacitors and aims to deliver constant power to the distribution network, even when the power production is zero. However, this technique allows constant power just for a few minutes, once the ultracapacitor capacity is limited. The second strategy is based on the bank of batteries combined with ultracapacitors, forming the hybrid storage system. In this management structure, the storage devices communicate with each other in order to perform a power sharing, resulting in a filtrated power profile delivered to the distribution network. In this strategy, the batteries are responsible to providing average power while ultracapacitors are in-charge of the transient power, sparing the batteries from supplying power peaks. In a second moment, two other load sharing methodologies are proposed for hybrid systems, but are based on decentralized techniques, i.e. storage devices do not communicate with each other to make the power sharing. Experimental and simulated results will prove the effectiveness of the control strategies and management methodologies.