This Masters research proposes a new system which deals with the management of renewable energy sources in a domestic/commercial small scale environment. The aim of the project is to develop an intelligent system which will monitor current in individual circuit loads in a domestic/commercial environment and establish whether the load can be powered from mains supply or be switched to an alternative energy supply in a dynamic way. The alternative energy can be solar energy from photovoltaic panels, wind generators or hydro generation. The switching between supplies is decided by monitoring load currents using a microcontroller and the switching action is taken only at specic allowed instants. The CAN (Controller Area Network)communication system is a two-wire differential serial bus system, developed by Bosch for automotive applications in the early 1980s. Its reliability and robustness in communication between nodes within the control system are the reasons for its popularity. The CAN system is implemented in the Eco Energy Controller. The prototype of the Eco Energy Controller is operational and has been tested with 6 resistive load, 24mH inductive load, and three 25W incandescent light bulbs. Experimental measurements and waveforms indicate that the prototype is successful in switching between two supplies to each of the loads without causing high current peaks during turn on.

Wind power can be related to natural disasters in several ways. This licentiate thesis gives some background and introduces four papers devoted to two aspects of this relation. The first section looks into how small-scale wind energy converters (WECs) could be used to generate power after a natural disaster. For this application diesel generators are the most common solution today, but there would be several advantages of replacing these systems. A study of off-grid systems with battery storage at 32 sites showed that photovoltaics (PV) were more suitable than WECs. The results were confirmed by a study for the entire globe; PV outperformed WECs at most sites when it comes to small-scale application. This is especially true for areas with a high disaster risk. Hybrid systems comprising both PV and WECs are however interesting at higher latitudes. For the Swedish case, it is shown that gridded data from a freely available meteorological model, combined with a statistical model, give good estimates of the mean wind speed at 10 meters above ground. This methodology of estimating the mean wind speed can be used when there is no time for a proper wind measurement campaign. The second section is directed towards wind power variability and integration. The results presented in the thesis are intended as a basis for future studies on how a substantially increased wind power capacity affects the electric grid in terms of stability, grid reinforcement requirements, increased balancing needs etc. A review of variability and forecastability for non-dispatchable renewable energy sources was performed together with researchers from the solar, wave and tidal power fields. Although a lot of research is conducted in these areas, it was concluded that more studies on combinations of the sources would be desirable. The disciplines could also learn from each other and benefit from the use of more unified methods and metrics. A model of aggregated hourly wind power production has finally been developed. The model is based on reanalysis data from a meteorological model and detailed information on Swedish WECs. The model proved very successful, both in terms of low prediction errors and in the match of probability density function for power and step changes of power. / Vindkraft kan relateras till naturkatastrofer på flera olika sätt. Den här licentiat\-avhandlingen ger bakgrund till och introducerar fyra artiklar som beskriver två aspekter av detta samband. I den första avdelningen undersöks hur småskalig vindkraft skulle kunna användas för att generera el efter en naturkatastrof. I dagsläget är det dieselaggregat som används för detta ändamål, men det skulle finnas stora fördelar med att övergå till förnybara system. En studie av 32 platser (myndigheten MSB:s utlandsstationeringar augusti 2012) visade att solceller var mer lämpade än vindkraftverk. Resultaten bekräftades av en studie för hela världen; solceller ger billigare system än småskaliga vindkraftverk för de flesta platser, inte minst om man tittar på områden som är utsatta för naturkatastrofer. Hybridsystem med både solceller och vindkraftverk var dock intressanta på högre breddgrader. För Sverige så visas det att data från en fritt tillgängliga meteorologisk modell tillsammans med en statistisk korrigering beroende på terrängtyp ger bra uppskattningar av medelvinden på 10 meters höjd. Den föreslagna metodiken kan vara användbar som ett komplement till vindmätningar eller om det inte finns tid eller möjlighet till en riktig mätkampanj. Den andra avdelningen är inriktad mot vindens variabilitet och integrering av vindkraft i kraftsystemet. De resultat som presenteras i denna avhandling är tänkta som en bas för framtida studier av hur en kraftigt ökad andel vindkraft påverkar elsystemet med avseende på stabilitet, nödvändiga nätförstärkningar, ökade krav på balanskraft etc. En översiktsstudie av variabilitet och prognosbarhet för intermittenta förnybara energikällor gjordes tillsammans med forskare inom sol-, våg och tidvattenkraft. Även om mycket forskning pågår inom dessa områden så var en slutsats att mer studier för kombinationer av olika källor skulle vara önskvärt. Forskare inom de olika disciplinerna skulle också kunna lära från varandra och dra fördel av gemensamma metoder och mått. Slutligen har en modell av aggregerad timvis vindkraftproduktion tagits fram. Modellen baseras på data från en meteorologisk modell samt detaljerad information om vindkraftverk i Sverige. Modellen visade sig vara mycket träffsäker, både vad gäller låga prediktionsfel och i överensstämmelse av sannolikhetsfördelning av effekt och stegförändring av timvis effekt.

Le travail présenté dans cette thèse s’inscrit dans la thématique « intégration de puissance ». Il porte sur l’étude des propriétés du matériau ferrite NiZnCu nanostructuré produit par SPS (frittage simple et réactif) et la réalisation de composants électromagnétiques monolithiques intégrés et leurs caractéristiques électriques. Les objectifs fixés au début de la thèse ont été atteints. Nous avons montré que des ferrites nanostructurés ayant des bonnes propriétés peuvent être obtenues par SPS. Pour un frittage simple, les principales caractéristiques structurales, diélectriques et magnétiques ont été déterminées pour différentes températures et temps de densification. Ces échantillons frittés montrent qu’après une décarburation et des valeurs élevées de résistivité électrique, des faibles valeurs de la permittivité diélectrique, et des valeurs élevées de permabilité magnétique initiale et du facteur de mérite peuvent être obtenues et controlées par le temps et la température de frittage. La synthèse in-situ par SPS montrent aussi des propriétés similaires à celles obtenues par frittage simple. Nous avons aussi montré, pour des oxydes de départ de taille nanométrique, que les conditions de broyage et la synthèse in-situ par SPS permettent de concevoir des ferrites ayant des propriétès intéressantes avec des pertes constantes jusqu’à 3 MHz à 15 mT et jusqu’à une température voisine à 60 °C. Les derniers obectifs ont été aussi atteints, l’ensemble des cofrittages du ferrites avec des matériaux conducteurs et diélectriques montrent qu’il est possible de réaliser des composants électromagnétiques monolithiques intégrés. Ces cofrittages montrent que le ferrite est compatible avec le cuivre, le titanate de barrium et des bandes coulées de diélectriques. Des composants inductifs et des transformateurs intégrés ont été réalisées. Les caractéristiques fréquentielles des composants inductifs montrent que l’insertion du diélectrique augmente les performances du composant en reduisant les pertes et l’impact des courants de polarisation. Pour les transformateurs réalisés avec diélectriques les résultats n’ont pas été satisfaisants. Seul un transformateur sans matériau diélectrique a pu être réalisé et testé et comme attendu, le coefficient de couplage entre le primaire et secondaire s’est avéré faible. / The work presented in this thesis is part of the theme «power integration». It covers the study of the nanostructured NiZnCu ferrite material sintered by SPS (simple and reactive sintering) and the realization of monolithic integrated components.The objectives set for the thesis have been achieved. We have shown that nanostructured ferrites with good properties can be obtained by SPS. For a simple sintering, the principal structural, dielectric and magnetic characteristics were determined for different temperatures and densification duration. These sintered samples after decarburization exhibit high electrical resistivity, low dielectric permittivity, high initial magnetic permeability and merit factor.These characteristics can be controlled by sintering time and temperature. The in-situ synthesis by SPS also shows similar properties than those obtained by simple sintering. We have also shown that the starting from oxides of nanometric size, the milling conditions and the in-situ synthesis by SPS can lead to design ferrites with interesting properties with constant losses up to 3 MHz, at 15 mT and up to a temperature of 60 °C.Other the last objectives were also achieved. The co-sintering of ferrites with conductives and dielectric materials show that is possible to produce monolithic integrated electromagnetic components. These experiments show that the co-sintering ferrite is compatible with copper, barrium titanate and dielectric green tape. Inductive components and transformers were designed and fabricated. The frequency characteristics of inductive components show that the insertion of a dielectric increases the performance of components. Indeed, with dielectric, losses are lower and there is less variation in series resistance and inductance with bias current. For transformers with a dielectric layer, the results aren't satisfactory because the dielectric between the primary and secondary melts, during the fabrication creating a short-circuit. The low values of the coupling coefficient and efficiency of the transformer fabricated without a dielectric were predictable because of the large leakage inductance associated with the presence of a magnetic layer between the two windings of the transformer.

Wind power generation does, on the one hand, contribute to a less polluting and more sustainable electric power generation mix. On the other hand, the uncertainty and the variability of the power output do challenge the operation of the power system: hourly variations in wind power generation are hardly predictable in a precise way. To decrease the need for balancing power, it might be beneficial from the overall system-perspective to subject power generating companies to stricter balancing incentives/rules. The way the market is designed has become crucial to exploit the existing flexibility in the power system and to increase the efficiency in its operation: inappropriate market designs can counteract all technical achievements. The work conducted for this thesis is embedded in a project on wind power integration and electricity market design following the aim to develop a simulation tool to analyse the consequences of changes in specific market rules. This thesis analyses wind power variations and forecast errors in the Swedish power system and explores the question whether internal ex-ante self-balancing can efficiently reduce the need for balancing power. Applying internal ex-ante self-balancing, every power generating company re-schedules its own power plants in order to balance its commitments towards other market actors with its newest production forecast. This is done shortly before the hour of delivery. To assess the value of this self-balancing, possible trading and scheduling decisions for power generating companies are modelled based on a hydro-thermal generation portfolio within the framework of the Nordic electricity market design. The model is based on a sequence of mixed-integer linear optimisation problems for the clearing of the different sub-markets. Both the data and the model have an hourly time resolution. In a case study, the model is applied on a simplified test-system. The need of real-time balancing by the transmission system operator, the total variable generation cost of the system, as well as the extent to which the power generating companies re-scheduled their production are then used as indicators to evaluate self-balancing. / <p>QC 20121017</p> / Short-term hydro power planning in power systems with large amounts of wind power / Elektra 36141: Korttidsplanering av vatten-värmekraftsystem vid stora mängder vindkraft: System-perspektivet

Les convertisseurs électroniques de puissance sont voués à fonctionner sous des conditions applicatives de plus en plus sévères tout en respectant les impératifs d’efficacité énergétique et de fiabilité. Or, les besoins industriels tendent vers un plus haut niveau d’intégration fonctionnelle tout en améliorant le rapport qualité-prix. Dès lors, la solution utilisée pour le report des puces semi-conductrices est le siège de densités de courant importantes et d’un flux thermique élevé. La présence de défauts dans cette couche d’interconnexion peut conduire à la dégradation de ses performances et au vieillissement prématuré du composant. L’objectif de nos recherches est d’évaluer la pertinence d’une méthodologie basée sur la confrontation de simulations numériques et de campagnes expérimentales. L’objectif est d’améliorer la compréhension du comportement électrothermique en régime de conduction d’un transistor MOSFET en présence d’un void dans sa brasure. Dans cette manuscrite, nous présenterons la construction d’un modèle intégrant le couplage électrothermique de la partie active qui sera confronté à la réponse de résultats expérimentaux. Puis, une étude numérique basée sur la théorie des plans fractionnaires, qui minimise le nombre de simulations, sera exploitée afin de quantifier l’impact de la taille et de la position du défaut sur la réponse électrothermique du composant et de ses liaisons électriques. Les détails de la mise en place d’une étude expérimentale analogue permettront de mettre en perspective la complémentarité de cette approche. / Power converters nowadays are required to function under harsh conditions in meeting energy efficiency and reliability requirement. Whereas, industrial specifications tend toward a higher level of power integration in respect to the cost constraint. As a result, the die attach is one of the key elements in power module packaging because of high current densities and high heat flow which are transported through. Void formation in the die attach may lead to performance degradation and premature aging of the component. This study introduces a methodology based on the comparison of numerical simulations and experimental campaigns. The obtained results help to improve our understanding on the electro-thermal behaviour of MOSFETs with solder voids. In this thesis, we depict a finite element model in which electro-thermal coupling of a MOSFET active layer is taken in to account. Simulation results will be correlated to the experimental responses. Later on, a parametric numerical study based on the response surface method (RSM) which minimizes the number of simulations and future tests will be exploited to quantify the impact of void position and size on several selective performance criteria. A future serial experimental study in respect to the same RSM design is expected in prospect, in order to fulfil the complementarity for this approach.

L’augmentation des fréquences de commutation des alimentations induit de nouvelles problématiques pour les composants. Que ces composants soient actifs ou passifs, il est nécessaire de contrôler les pertes afin que les rendements restent acceptables. La thèse se propose d’étudier et de fabriquer une nouvelle structure de transformateur destiné à s’insérer dans une alimentation à découpage. Ces transformateurs sont produits à l’aide du procédé PECS/SPS, qui est une technologie de frittage. Cette technologie permet de fritter des ferrites tout autour des enroulements primaires et secondaires. Il en résulte que les composants sont monolithiques.Une première partie présente l’état de l’art, ainsi que le magnétisme dans la matière. Il s’ensuit un chapitre dédié à la fabrication des matériaux magnétiques utilisés durant la thèse : les ferrites.Une deuxième partie concerne les ferrites fabriqués par le procédé PECS/SPS. Il est question dans un premier temps d’étudier l’anisotropie magnétocristalline de ces matériaux, et il est possible de la diminuer en jouant sur la composition chimique. Dans un second temps, d’autres grandeurs telles que la perméabilité ou la polarisation sont mesurées, toujours en fonction de la composition chimique. Les principaux résultats montrent que le frittage par le procédé PECS/SPS est plus réducteur que le frittage classique, ce qui dégrade certaines propriétés comme la résistivité des ferrites. Un dernier chapitre est dédié à la réalisation des transformateurs monolithiques. Un protocole détaillé de la fabrication est alors présenté.Une troisième partie illustre le fonctionnement des transformateurs réalisés. Les mesures usuelles permettent d’identifier les inductances propres, mutuelles et de fuite. Les valeurs de ces inductances montrent qu’il est plus judicieux d’utiliser les composants fabriqués non pas en tant que transformateur, mais en tant que coupleur. Enfin un convertisseur basé sur une structure de type VRM est réalisé. La fréquence de découpage est de 2 MHz, le rendement est supérieur à 90 %, et la densité de puissance est de 15 kW/litre. / The increase in switching frequency of power supply induces new problems for the components. These components are active or passive, it is necessary to control the losses so that efficiency remains acceptable. The thesis deals with the study and production of a new transformer structure intended to be part of a switching power supply. These transformers are produced using PECS/SPS method, which is a sintering technology. This technology can be sintered ferrite around the primary and secondary windings. It follows that the components are monolithic.A first part presents the state of the art, and magnetism in the matter. It follows a chapter dedicated to the manufacture of magnetic materials used in the thesis : the ferrites.A second part concerns the ferrites produced by the PECS / SPS process. Firstly, the magnetocrystalline anisotropy of these materials is studied, and it is possible to decrease it by varying the chemical composition. In a second stage, other variables such as the permeability or the polarization are measured, always depending on the chemical composition. The main results show that the sintering by PECS / SPS method is more reducing than conventional sintering, which degrades certain properties such as the resistivity of the ferrites. The last chapter is dedicated to the realization of monolithic processors. A detailed manufacturing protocol is presented.A third part shows the operation of the realized transformers. The usual measurements allow identifying self, mutual and leakage inductances. The values of these inductances show that it is better to use components made not as a transformer, but as a coupler. Finally a converter based on a VRM structure is realized. The switching frequency is 2 MHz, the efficiency is greater than 90%, and the power density is 15 kW / liter.

Energy mix modellers often use a constant emissions factor model, which more or less implies a constant heat rate, when trying to show the emissions reduction benefits of integrating renewable power generation system on the grid. This approach does not consider the fact that there is a deterioration in the heat rate with load for the Coal Fired Power Plants that need to accommodate the additional renewable supply. If varying heat rate were to be included in a study, it is often limited to plant specific cases. This PhD presents a novel Variable Turbine Cycle Heat Rate (V-TCHR) model for predicting the part load Turbine cycle heat rate (TCHR) response of various Coal Fired Power Plant (CFPP) architectures, without detail knowledge of the entire steam cycle parameters. A total of 192 process models of representative CFPP architectures were developed using a Virtual Plant software. The models had different combinations of the degree of reheat; the throttle temperature; throttle pressure; and condenser cooling technology. The part load response of all the models were simulated using the software.

Les principaux critères de comparaison des convertisseurs sont le rendement, la masse, le volume, le coût et la fiabilité. Le contexte environnemental et économique et le développement des applications nomades ouvrent à l’électronique de puissance un domaine d’application de plus en plus vaste. Mais pour imposer cette technologie, il faut sans cesse améliorer ces performances et les compromis entre celles qui sont antagonistes (augmentation du rendement et diminution de la masse par exemple…) ce qui amène naturellement à la problématique de conception et d’optimisation. Le cas spécifique de l’aéronautique n’échappe pas à la règle et les contraintes y semblent encore plus fortes. La réduction de la masse, du volume et l’augmentation du rendement et de la fiabilité sont parmi les défis principaux actuels, et la transition de systèmes hydrauliques ou pneumatique vers des systèmes électriques laisse espérer à une amélioration des performances globales de l’avion. Les architectures des convertisseurs sont un moyen efficace d’améliorer les convertisseurs parce qu’ils permettent de réduire les contraintes au sein des convertisseurs tout en améliorant les formes d’onde en entrée et/ou en sortie. Parallèlement, les composants classiques en silicium ont bénéficié de larges avancés au cours de ces dernières décennies et approchent de leurs limites théoriques. Pour espérer une amélioration, des technologies en rupture sont désormais nécessaires. Au cours de ces dernières années, les technologies de semi-conducteurs dit « à grand gap », essentiellement à base de Nitrure de Gallium ou de Carbure de Silicium (resp. GaN et SiC) se sont considérablement amélioré et sont d’ores et déjà plus performant que les composants Si dans de nombreux cas. Les semi-conducteurs étant généralement plus performants lorsqu’ils ont une tenue en tension plus faible, on envisage ici de cumuler plusieurs avantages en envisageant la mise en série de composants GaN basse-tension pour améliorer l’intégration des convertisseurs de puissance. Dans un premier temps, un convertisseur multi-niveaux élémentaire de type Flying Capacitor (FlyCap) est mis en oeuvre. Des condensateurs de puissance intégrés sont utilisés, ce qui pourrait permettre de réduire l’empreinte de ces composants et de proposer une dissipation thermique commune par le dessus des composants. L’utilisation de composant au temps de commutation réduit est critique pour la fiabilité des convertisseurs. Une étude de l’influence des paramètres physique du circuit électrique sur les inductances parasites de la maille de puissance et de commande est menée permettant de mettre en évidence des règles de conception dans le but d’améliorer la fiabilité des convertisseurs. Dans un second temps, l’équilibrage dynamique de la topologie FlyCap qui est critique pour les formes d’onde et la sureté de fonctionnement est étudié. La prise en compte des pertes dans les semi-conducteurs permet d’améliorer l’estimation de la dynamique d’équilibrage. Une base de réflexion sur le dimensionnement d’un équilibreur passif est également proposée pour optimiser sa dynamique et les pertes associées. Un prototype expérimental à 5 cellules de commutation est présenté permettant d’atteindre une tension d’entrée de 270 V avec des composants 100V. / Performance, weight, volume, cost and reliability are key criteria to compare converters. Environment and economical context and the development of mobile applications lead electronics to have a wider field of application. Improving performances and tradeoff between conflicting characteristics (high efficiency and reduced weight for example) is thus constantly needed to impose this technology, which calls for design and optimization methods and tools. The specific case of aeronautics is no exception and there is in this field a high demand. Mass and volume reduction, efficiency and reliability improvement is one of the most important challenges, and the change from hydraulic and pneumatic systems to electric systems is expected to allow a global improvement of aircraft performances. Converter’s topology is a good candidate to improve and reduce the size of converters because it can reduce stress while improving the input and/or output waveforms. Meanwhile, conventional silicon components have taken advantage of wide advances in recent decades and are now close to their theoretical limits. To hope for a significant improvement, breaking technologies are now needed. In recent years, GaN and SiC Wide Band Gap semiconductors have seen significant development and are already often better than Si power devices. Lowvoltage semiconductors are generally better than higher voltage ones. Thus, we consider here cumulating advantages with a serial arrangement of low voltage GaN semi-conductors to improve power converter’s integration. First, a basic multilevel Flying Capacitor GaN-based converter is implemented. The integration of power capacitors is proposed to evaluate this technology, which could reduce the footprint of these components and could allow a common heatsink dissipation through the top of the components. Very fast turn-on and turn-off of GaN devices is critical for safe operation due to parasitic inductances. A study of physical parameters of the electrical circuit on parasitic inductances of power and control loop is conducted to lay down design rules in order to improve the reliability of converters. Secondly, dynamic balancing of Flying Capacitor which is critical for the waveforms and reliability is studied. Semi-conductor’s losses are considered to improve the estimation of dynamic balancing. A method for the design of a passive balancer is also proposed to optimize the balancing and associated losses. An experimental prototype with 5 switching cells is presented to achieve an input voltage of 270 V with 100 V rated voltage devices.

The Master Thesis is part of the Smart Grid Gotlandproject. This project aims at implementing smart grid solutionson the island of Gotland in order to be able to efficientlyintegrate large quantities of renewable energy production.In situations of high wind power production and lowconsumption, energy export problems may occur betweenGotland and the mainland. A novel approach to manageanticipated congestions, compared to traditional gridreinforcements, consists of using flexibility from demandresponse(DR) resources. However, such an approach presentschallenges as it requires both technical and economic considerations.This Master Thesis proposes and analyses twomarket-based strategies applied to detached houses for dayaheadcongestion management. The strategies are implementedin an Ancillary Service toolbox developed in theMATLAB programming environment.The first strategy involves using a dynamic network tariffwhile the second uses spot price optimization. Simulationsare performed for seasonal worst-case congestion scenarioswhile satisfying comfort and economic constraints ofthe DR participants. A sensitivity analysis is carried out toassess the impact of different spot price profiles and windpower production prognosis errors on the results.Results show that congestions are managed with a feasiblenumber of participants, but that their savings are negligiblefor both strategies (between 2 and 40 SEK/participant).Moreover, using a dynamic network tariff strategy impliesa DSO cost in the range of 1700-89000 SEK. These resultsapply for a 3-days congestion period, which is estimated tooccur 5-6 times a year if the maximum hosting capacity isincreased by 5 MW.To conclude, an AS toolbox with economic constraintsis feasible for Gotland conditions with a reasonable numberof DR participants. However, the simple cost-benefitanalysis that was carried out showed that the AS toolboxapproach was still much more costly than traditional gridreinforcement.

According to the 20-20-20 targets set by the European Union, 50 percent of the Swedish electricity share is to be provided by renewable energy sources by 2020. The Smart Grid Gotland (SGG) project has emerged as a response to this target. The project aims at demonstrating a proof of concept on how smart grid solutions can be used to integrate large quantities of renewable energy sources in an existing network. The outcomes of the project are intended to pave the way for future renewable energy integration projects in Sweden. The Thesis focuses on one of the technical objectives of the SGG project, i.e. to increase the hosting capacity of wind power on Gotland from 195 MW to 200 MW by using Demand-Response (DR) from households and industries. DR consist of shifting peak-loads to peakproduction hours. The integration of additional wind power causes a risk of exceeding the transmission capacity of the power export cable between Gotland and the Swedish mainland. The approach considered for this Thesis is to use an Ancillary Service (AS) toolbox scheme based on multi-agent systems. The AS toolbox consist of flexibility tools such as DR on long-term, short-term, a battery energy storage system and a wind curtailment scheme. The DR activity includes space heating and domestic hot water consumption from detached houses on Gotland. The simulation results indicate that 1900 household participants are sufficient to balance the additional 5 MW for worst case scenarios. Furthermore, it is shown that the DR participation from industries contributes in some cases to a reduction of 700 household participants. The findings helped conclude that using an AS toolbox solution on Gotland is fully possible from a technical perspective. However, barriers that stand against its realisation are of economical nature and need to be investigated in future studies.