Yes / Investigation of the environmental/economic optimal operation management of a microgrid (MG) as a case study for applying a novel modified multi-objective grey wolf optimizer (MMOGWO) algorithm is presented in this paper. MGs can be considered as a fundamental solution in order for distributed generators’ (DGs) management in future smart grids. In the multi-objective problems, since the objective functions are conflict, the best compromised solution should be extracted through an efficient approach. Accordingly, a proper method is applied for exploring the best compromised solution. Additionally, a novel distance-based method is proposed to control the size of the repository within an aimed limit which leads to a fast and precise convergence along with a well-distributed Pareto optimal front. The proposed method is implemented in a typical grid-connected MG with non-dispatchable units including renewable energy sources (RESs), along with a hybrid power source (micro-turbine, fuel-cell and battery) as dispatchable units, to accumulate excess energy or to equalize power mismatch, by optimal scheduling of DGs and the power exchange between the utility grid and storage system. The efficiency of the suggested algorithm in satisfying the load and optimizing the objective functions is validated through comparison with different methods, including PSO and the original GWO. / Supported in part by Royal Academy of Engineering Distinguished Visiting Fellowship under Grant DVF1617\6\45

Nearly one fifth of the global population lacks access to electricity and electricity access is essential for economic growth and human well-being. SHSs and micro-grids both have the possibility of increasing the electricity access in developing countries. The decision to choose either SHSs or micro-grids for rural electrification is a complex task that must consider both the technological factors that separate these two systems and the non-technological factors. Separate times of peak load between households (inter-class diversity) has shown to be one major advantage for the use of micro-grids. Studies have shown that the diversity factor present in micro-grids can scale down the necessary capacity of PV modules and energy storage of up to 80%, in comparison to stand-alone systems (e.g. SHSs). These reductions are nevertheless based on assumed diversity factors, not using real load profiles and the necessary capacities are calculated using intuitive methods (known to be inexact). From interviews in a rural community of Nicaragua, the author generated load profiles and determined the diversity factor of the community. The load profiles were generated with a specially designed software to formulate realistic load profiles for off-grid consumers in rural areas. These load profiles were later used in the software HOMER where the diversity’s influence on required capacity and NPC were determined by comparing SHSs to a PV based micro-grid. The study showed that the required capacity and NPC of the inverter and charge controller are clearly decreased as an influence of inter-class diversity. The required PV and battery capacity are also decreased when a micro-grid is utilized, but these reductions are most likely a result from the limited nominal power per component considered in HOMER. / Nästan en femtedel av världens befolkning saknar tillgång till elektricitet. Nicaragua är ett av de länder där en stor del av befolkningen saknar eltillgång och det gäller speciellt hushållen på landsbygden. Utbyggnader av elnätet till dessa områden är ofta låg-prioriterade på grund av höga kostnader för att tillgodose ett många gånger lågt energi och effektbehov. En alternativ lösning för att ge dessa hushåll tillgång till elektricitet är att använda off-grid system, system frikopplade från det nationella elnätet. Två vanligt förekommande off-grid system är solar home systems (SHSs) och micro-grids. Det faktum att flera hushåll ofta använder sin toppeffekt vid olika tillfällen (sammanlagring av effekt) har visat sig vara till stor fördel för micro-grids. Tidigare studier har visat att sammanlagringsfaktorn i ett micro-grid kan reducera nödvändig kapacitet av solceller och energilager upp till 80%, i jämförelse med enskilda system (t.ex. SHSs). Dessa studier bygger dock på antagna sammanlagringsfaktorer, overkliga lastprofiler och nödvändig kapacitet beräknas med intuitiva metoder. Med data från intervjuer i ett landsbygdssamhälle i Nicaragua skapas lastprofiler och en sammanlagringsfaktor beräknas för samhället. Lastprofilerna skapas i en programvara utvecklad för att formulera realistiska lastprofiler för off-grid konsumenter i landsbygdsområden. Lastprofilerna används senare i programvaran HOMER där sammanlagringens påverkan på nödvändig kapacitet och kostnad undersöks genom en jämförelse mellan SHSs och ett solcellsdrivet micro-grid. Studien visar att nödvändig kapacitet och nuvärdeskostnad för växelriktare och laddningsregulator tydligt minskar till följd av sammanlagring. Nödvändig kapacitet på solceller och batterier minskar också när ett micro-grid används. Dock beror detta med stor sannolikhet inte på sammanlagring utan är ett resultat från de begränsade märkeffekter på komponenter som användes i HOMER.

Depuis 2004, l'Université de Paris Sud a établi une collaboration avec le département de Génie Électrique de la Faculté d'ingénierie de l'Université du Laos (UNL). La thématique de recherche concerne le pilotage de l'électronique de puissance pour la gestion de sources d'énergie renouvelable pour le Laos. Ainsi en 2009, le Gouvernement français a financé une bourse de thèse pour le développement d'un outil de pré-dimensionnement de la production électrique renouvelable pour les villages isolés au Laos. En effet, le réseau de transport et de distribution du Laos est déjà en tension compte tenu de l'explosion de la consommation dans les zones urbaines. Son extension aux zones rurales notamment dans les zones montagneuses représente un coût d'investissement beaucoup trop élevé. Par contre le pays bénéficie de ressources naturelles (hydrauliques, solaire et agricoles) dont l'exploitation judicieuse peut permettre le développement de la filière des énergies renouvelables. La production d'énergie électrique décentralisée (fermes solaires par exemple) nécessite une évaluation des ressources locales et un dimensionnement optimal de l'ensemble des constituants (sources, dispositifs de stockage, convertisseurs, etc.) et de l'architecture du mini ou micro réseau autonome.Cette thèse est organisée en 3 chapitres :Le chapitre 1 présente dans un premier temps le travail qui permit d'identifier les besoins et les ressources effectivement disponibles au Laos. Pour cela, un séjour de plusieurs semaines dans des zones rurales reculées du Nord-Ouest du Laos a été effectué. Cela a permis d'obtenir un profil de consommation standard, d'identifier les ressources et de relever les données des réseaux rudimentaires existants (puissance et configuration). Une importante recherche bibliographique sur les outils logiciels existants a ensuite été réalisée. Cela a permis de dimensionner et de simuler ces systèmes autonomes. Le chapitre 2 présente les limitations de ces outils de conception (absence de flexibilité dans les modèles utilisés et algorithmes d'optimisation trop contraints) et le développement dans l'environnement de Matlab-Simulink d'une bibliothèque de modèles des constituants du système d'énergie autonome. Les modèles sont réalisés pour faciliter un dimensionnement optimal du système selon des critères de coût, de disponibilité et de fiabilité. Un important travail d'étude bibliographique sur les architectures de réseaux a été réalisé et combiné à une synthèse des ressources et des besoins des milieux ruraux au Laos. Le chapitre 3 présente deux exemples de dimensionnement de systèmes de production d'électricité pour des sites isolés au Laos à partir d'énergie renouvelables. Le cahier des charges correspond à un village isolé de 50 maisons pour 130 habitants. Le critère économique est fondamental dans cette étude où l'optimisation cherche à réduire les coûts des constituants tout en satisfaisant les besoins en puissances des villageois. Différentes optimisations continue et hybrides (continu et entier) sont conduites en tenant compte de contraintes sur les sources. Des indicateurs de performance sont ainsi utilisés: "Loss of Power Supply Probability, Forced Outage Rates, Annualized Cost of System, Levelized Cost of Energy, etc.". / Since 2004, a collaboration between Université Paris Sud of France and the Department of Electrical Engineering Faculty of Engineering, National University of Laos (NUOL) has been carried out on the control of power electronics for the management of renewable energies source in Laos. Therefore in 2009, the French Government has funded a PhD thesis on the development of a designing tool for the early-sizing of renewable electricity production for isolated villages in Laos. This thesis report is organized in three chapters:Chapter I presents a short review of the status and development plans for the electrification of Laos. Then, based on a two-month field study in Northern Laos, analyses of energy consumptions of households in isolated villages and available renewable sources, using small scale hydro power plants and solar systems among others, are presented. Afterward, micro-grid configurations and technologies adapted to Laos are discussed. Obtained results are used in the next chapters as specifications for the designing tool.Chapter II focuses on software tools for system design and system modeling. First, a short review of the existing early-sizing tools for renewable energy sources for isolated villages is presented. But an analysis of evaluated software's such as LEAP, HOMER, HOGA, etc. shows that they are not opened enough to facilitate the development of a flexible and scalable designing too. Thus, Matlab/Simulink software is chosen as an open and highly adaptable architecture research tool. Then, specific models for renewable sources, storage devices, grid configuration are developed in order to facilitate the optimization procedures of an off-grid system design. After that, a short review of the existing optimization algorithms, available in Matlab, is carried out. Then, a paralleled mono-objective Genetic Algorithm is configured and applied in the next chapter.Chapter III presents several designs of isolated villages in Laos, using renewable energies. The specifications focus on isolated villages of about 50 houses for 120 inhabitants. The economic aspect is a key point in order to minimize costs of designed system while satisfying daily load demands of the village. For this task, locally available natural resources such as rivers and solar radiation are considered as energy sources. Various optimizations using continuous and discrete optimization algorithms are conducted taken into account the sources constraints and a short review of the existing hybrid system performance indicators is carried out, such as: Loss of Power Supply Probability, Forced outage rates, Annualized Cost of System, Levelized Cost of Energy, etc. Finally, the results obtained in this thesis show that renewable sources can be used at a reasonable price for off-grid electrification of isolated villages in Laos. Moreover, the developed designing tool can easily be adapted to new models of renewable sources and storage devices, which is the main interest of a designing tool for the early-sizing of off-grid renewable electricity production for isolated villages in Laos.

Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2017-07-10T14:32:15Z No. of bitstreams: 1 Luís Rodrigo Becker_.pdf: 4479543 bytes, checksum: 3a9259e64d112cb88c2414eb122552e9 (MD5) / Made available in DSpace on 2017-07-10T14:32:15Z (GMT). No. of bitstreams: 1 Luís Rodrigo Becker_.pdf: 4479543 bytes, checksum: 3a9259e64d112cb88c2414eb122552e9 (MD5) Previous issue date: 2017-03-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / PROSUP - Programa de Suporte à Pós-Gradução de Instituições de Ensino Particulares / Este trabalho apresenta uma análise experimental de uma microrrede fotovoltaica formada por dois subsistemas, um isolado com estocagem e outro conectado à rede. Foi verificado o seu comportamento, sua capacidade no fornecimento de energia para uma carga isolada e rede da concessionária, monitorado a qualidade da energia elétrica entregue à diferentes cargas e rede da concessionária e também quantificado os índices de performance do sistema conectado. O subsistema conectado à rede (SFCR) é formado por um painel de 1080 Wp de silício multicristalino e um inversor c.c./c.a. de 1200 W. O subsistema isolado de back-up (SFI-b) é formado por um painel de 600 Wp de silício monocristalino, controlador de carga, banco de estocagem com baterias chumbo-ácido 24 V / 210 Ah e um inversor off-grid c.c./c.a. de 1000 W. O comportamento e a capacidade do sistema são monitorados durante o atendimento de uma carga, representada por um refrigerador. A qualidade da energia é analisada através de medições de energia ativa, reativa e aparente, fator de potência e geração de correntes harmônicas pelos inversores. O SFI-b é monitorado atendendo diferentes tipos e regimes de cargas. Já o SFCR é monitorado em dias de céu claro, parcialmente encobertos e encobertos. Os índices de performance são calculados em dias de céu claro e parcialmente encoberto ao longo dos seis primeiros meses de 2016. Os resultados demonstram que o SFI-b é capaz de atender a carga de forma confiável, comutando-a automaticamente para a concessionária quando o banco de baterias atinge uma profundidade de descarga pré-definida, enquanto o SFCR injeta a energia produzida na rede da concessionária. Os indicadores de qualidade da energia do inversor do SFI-b mostraram-se adequados, permanecendo dentro dos limites citados na legislação e análogos aos apresentados pela rede da distribuidora local. Já o inversor do SFCR apresentou indicadores de qualidade de energia satisfatórios, também na maior parte do tempo dentro dos limites citados na legislação, exceto nos dias encobertos e períodos de baixa irradiância, constatando-se significativa geração de energia reativa e distorções harmônicas de corrente. Considerando a média entre dias de céu claro e parcialmente encoberto, a eficiência média global do SFCR é de 9,9% e a energia média diária entregue à rede é de 4,7 kWh. Foi verificado que a qualidade da energia produzida pelo SFI-b praticamente independe da irradiância, já o SFCR depende diretamente da irradiância e do nível de carregamento do inversor, na geração de uma energia de qualidade. / This work presents an experimental analysis of a photovoltaic micro-grid formed by two subsystems, one off-grid with storage and another grid-connected. It is intended to verify its operation, its capacity to supply power to an isolated charge and electric utility grid, to monitor the quality of the electric power delivered to different charges and the electric grid power, and also to quantify the performance indexes of the connected system. The grid-connected subsystem (SFCR) consists of a panel of 1080 Wp of multicrystalline silicon and a DC/AC. inverter of 1200 W. The off-grid subsystem of back-up (SFI-b) consists of a 600 Wp monocrystalline silicon panel, charge controller, lead-acid battery storage bench 24 V / 210 Ah, and a DC/AC inverter of 1000 W. The operation and capacity of the system are monitored during the supply of a charge, represented by a refrigerator. The quality of the energy is analyzed through measurements of active, reactive and apparent energy, power factor and generation of harmonic currents by the inverters. SFI-b is monitored for different types and charges regimes, and SFCR is monitored on clear sky, partially and totally cloudy days. Performance indexes are calculated on clear sky and partly cloudy days over the first six months of 2016. The results demonstrate that the SFI-b is capable of servicing the charge reliably, switching it automatically to the utility grid when the batteries bank reaches a predetermined discharge depth, while the SFCR injects the power produced in power line grid. The energy quality indicators of the SFI-b inverter were adequate, staying inside the limits mentioned in the legislation, and analogous to those presented by the power line grid of the local distributor. The SFCR inverter presented satisfactory energy quality indicators, also in most of the time inside the limits mentioned in the legislation, except for the cloudy days and periods of low irradiance, showing significant reactive energy generation and current harmonic distortions. Considering the average between clear and partially cloudy days, the global average efficiency of SFCR is 9,9%, and the average daily energy injected on the grid is 4,7 kWh. It was verified that the quality of the energy produced by the SFI-b practically independent of the irradiance, but the SFCR depends directly on the irradiance and the load level of the inverter, in the quality energy generation.

Made available in DSpace on 2017-07-10T17:11:50Z (GMT). No. of bitstreams: 1 LUCIANO MAURO ARLEY SUP2.pdf: 2686269 bytes, checksum: 28a697be163c9a8e1f7c5d0c8abc16b6 (MD5) Previous issue date: 2012-04-20 / This work presents a physical and logical architecture of an intelligent Micro-Grid in order to perform the integrated energy management of the various distributed energy resources (REDs) of an organization. In this way, it is initially proposed an Integrated Energy Management System (SGIE), through which defines the action strategies for the supervision and control of the REDs, which identifies the needs and requirements to be met by the technology architecture. Subsequently, the document presents the concepts of Micro-Grid and how the monitoring and control system would help in the efficient and effective use of various energy resources in production, transformation or end use, to ensure that they are integrated into the operation of Micro-Grid. The presented paradigm is framed in new vision of power systems, known as Smart Grid. These smart grids might be formed from the union of several sub-networks package, called Smart µGrid, whose main concepts, requirements and technologies necessary to build are presented. Finally, it is presented a proposal for a Smart µGrid architecture, set in the Itaipu Technological Park, which aims to meet the need of its SGIE, but basically it is thought to work as a living laboratory in which it will be possible to learn concepts of smart grid acting on it. / No presente trabalho apresenta-se uma arquitetura física e lógica de uma microrrede inteligente com o objetivo de realizar a gestão integral da energia dos diversos Recursos Energéticos Distribuídos (REDs) de uma organização. Nesse sentido, inicialmente é proposto um Sistema de Gestão Integral da Energia (SGIE), através do qual são definidas as estratégias de atuação para a supervisão e controle dos REDs, o que permite identificar as necessidades e requisitos a serem atendidos pela arquitetura tecnológica.Posteriormente o trabalho apresenta os conceitos de microrredes e como o sistema de monitoramento e controle contribuiria no gerenciamento eficiente, efetivo e eficaz dos diversos recursos energéticos, seja na produção, na transformação ou no uso final, buscando que os mesmos estejam integrados à operação da microrrede. O paradigma apresentado está enquadrado na nova visão dos sistemas elétricos, conhecida como Smart Grid ou rede inteligente. Essas redes inteligentes podem ser formadas a partir da união de bolsões de sub-redes, denominadas Smart µGrid, das quais são apresentados os principais conceitos, requisitos e tecnologias viabilizadoras. Finalmente, é apresentada a proposta de arquitetura para uma Smart µGrid, ambientada no Parque Tecnológico Itaipu, a qual tem a finalidade de atender as necessidades do SGIE do mesmo, porém, fundamentalmente, o que se busca é que funcione como um laboratório vivo, através do qual será possível apreender conceitos de Smart Grid atuando sobre ela.

Le challenge de ces prochaines années est de réduire le plus possible les émissions de CO2 qui la première cause du réchauffement climatique. L’émission de CO2 est principalement due à l’utilisation du moteur thermique dans le milieu du transport. Pour diminuer cette émission, la solution réside à utiliser des véhicules électriques qui sont non polluants et rechargés par des sources émettant le moins possible de CO2. Mais cela impliquerait une production supplémentaire d’énergie. Aujourd’hui l’énergie électrique est produite principalement par des centrales thermiques au niveau mondial, des centrales nucléaires enFrance et des centrales hydrauliques au Québec. Les pics d’utilisations et de productions restant une problématique posant encore beaucoup de problèmes.Une utilisation croissante de véhicules électriques ou hybrides rechargeables permettrait de pouvoir disposer de systèmes de stockage d’énergie, permettant à la fois d’alimenter le moteur électrique du véhicule ou d’aider le réseau électriques. Ce flux est appelé Vehicle-to-Grid ou plus précisément dans le travail présenté ici, ce flux s’appelle Vehicle-to-Home. Alimenter la maison via la batterie du véhicule, permet de diminuer le pic de consommation du foyer. De plus, la batterie du véhicule peut être chargée durant la nuit lorsque la production d’énergie est au plus bas et la moins chère.Ce document présente une optimisation offline du système qui inclut les différents flux d’énergie. Cette optimisation a été réalisée à l’aide de la programmation dynamique. L’objectif de cette optimisation est de minimiser le coût de l’énergie que ce soit le coût de l’essence ou de l’électricité ou encore des énergies renouvelables installées localement.Ensuite deux contrôleurs flous localisés dans le véhicule et dans la maison ont été dimensionnés, testés par simulation (simulation online) et validés expérimentalement.Finalement cette recherche a mis en avant deux cas d’études: un en hivers et l’autre en été. Le cas d’hiver présente une réduction budgétaire de 40% dans la simulation offline, 27% dans la simulation online et 29% en expérimentation. D’autre part, le cas d’été montre une réduction budgétaire de 62% dans la simulation offline, 60% dans la simulation online et 64% en expérimentation. / The challenge for the next few years is to reduce CO2 emissions, which are the cause of global climate warming. CO2 emissions are mainly due to thermal engines used in transportation. To decrease this emission, a viable solution lies in using non-polluting electric vehicles recharged by low CO2 emission energy sources. New transportation penetration has effected on energy production. Energy production has already reached peaks. At the same time, load demand has drastically increased. Hence, it has become imperative to increase daily energy production. It is well-known that world energy production is mainly produced thermal pollutant power plants, except in Québec, where energy is produced by hydro power plants.The more recent electricity utility trend is that electric, and plug-in hybrid electric vehicles (EV, PHEV) could allow storage and/or production of energy. EV/PHEV batteries can supply the electric motor of the vehicle, and act as an energy storage that assists the grid to supply household loads. This power flow is called vehicle-to-grid, V2G. In this dissertation, the V2G power flow is specifically called vehicle-to-home, V2H. That is battery is used during peak. Moreover, the EV battery is charged during the night, when energy production is low and cheap. This important aspect of V2H is that the vehicle battery is not connected to the grid, but is a part of a house micro-grid.This dissertation presents an offline optimization technique, which includes different energy flows, between the home, EV/PHEV, and a renewable energy source (such as photovoltaic - PV and/or wind) which forms the micro-grid. This optimization has been realized through the dynamic programming algorithm. The optimization objective is to minimize energy cost, including fuel cost, electricity cost, and renewable energy cost.Two fuzzy logic controllers, one located in the vehicle and the second one in the house, have been designed, tested by simulation (online simulation) and validated by experiments.The research analyses two seasonal case studies: one in winter and the other one in summer. In the winter case, a cost reduction of 40% for the offline simulation, 27% for the online simulation and 29% for the experiment is realized whereas in the summer case a cost reduction of 62% for the offline simulation, 60% for the online simulation and 64% for the experiment is presented.

Electric power has become a basic necessity of human life. The major share of electric power comes from fossil fuel which results in global warming and pollution. A share of generated power comes from nuclear power which is equally dangerous. Big hydro projects take away lots of fertile land. The continuous usage of fossil fuel also poses a threat of petroleum and coal getting over in the near future. The only way out of this energy scarcity is to depend more and more on renewable sources like solar, wind and micro-hydro. At present, instead of having preference over any particular source of renewable energy, effort should be made to extract power from every possible energy source available in whatever form it is and use it in an optimal way. Like any renewable energy sources, the wind power contains large potential for harnessing energy that has been well understood hundreds of years ago. The importance of wind power generation has come to focus recently both at installation and research level and lot of activities are being carried out for efficient use of wind energy. There are different types of wind turbine designs available in the literature. But the most commercially used model is the two or three blade horizontal axis propeller type wind turbine. Research has shown that variable speed operation of this type of turbine is advantageous over fixed speed operation in terms of total energy synthesis. The most commonly used machines for wind power conversion are synchronous machine, squirrel cage induction machine and slip ring induction machine (SRIM). Variable speed operation using synchronous machine or squirrel cage induction machine requires large ratings of the power converters. However, SRIM based variable speed wind generator is advantageous over other schemes due to its inherent advantages like lower power rating for the converters, higher energy capture and the flexibility of sharing reactive power between the stator and the rotor. SRIM is used for both grid connected and stand alone applications and have been reported in the literature. The grid connected applications have received major attention in the literature whereas there are only a very few instances of its stand alone counterparts. There are many places both within and outside India where utility grid has not yet reached or the available grid is very weak. Moreover, in many of the places, the transmission line is so long that the losses in the system are extremely high. Isolated wind power generation can be of great advantage in such places where the available wind power is harnessed and utilized locally. This has been the motivation to go for proposing an isolated wind power generation scheme in this thesis. The proposed scheme is designed to supply power to the load even when very low or no wind power is available. Therefore, a battery bank is also a part of the system. The power converter assembly of the proposed scheme has three major components. One is the rotor side converter which is connected to the rotor terminals of the SRIM. The second one is the stator side converter with output LC filter which is connected to the stator side. These two converters share a common DC link which is interfaced to the battery bank through a multi phase bi-directional fly-back DC-DC converter. Fig. 1. Overall block diagram of the proposed stand alone wind power generator Functionally, this thesis proposes a system as shown in Fig. 1, which has primarily two components with multiple energy ports viz. (i) the SRIM is one triple energy port component and (ii) the proposed power conditioner is another triple energy port component. The SRIM device consists of (i) a mechanical energy port that is interfaced with the windmill shaft (ii) an AC port through the stator windings that is interfaced with the micro-grid/load and (iii) a third port which is also an AC port through the rotor windings of the SRIM that interfaces with an AC port of the proposed power conditioner. The proposed power conditioner is another triple energy port device which consists of (i) a DC energy port that interfaces with a battery/accumulator, (ii) an AC port that interfaces with the rotor windings of the SRIM and (iii) another AC port that generates the micro-grid that is connected to the load and the stator port of the SRIM. The proposed power conditioner provides the frame work for managing the energy flow from the mechanical port of the SRIM to the rotor and accumulator as well as from the mechanical port to the stator/load and accumulator. Further, energy interaction can also take place between the stator and the rotor externally through the power conditioner. The power interfaces on all three energy ports of the proposed power conditioner poses several challenges that have been discussed in this thesis. This thesis focuses on developing schemes to solve these challenges as explained below. Speed sensorless control is a natural choice for slip ring induction machine because of the flexibility of sensing both stator and rotor currents. There are different methods proposed in the literature which deal with the speed sensorless control of slip ring induction machine. However, the elimination of the measurement noise in the flux position estimation is not sufficiently addressed. It is important to address this issue as this would lead to deterioration in rotor side control of SRIM if the measurement noise is not eliminated. Primarily, the schemes which use algebraic relation between the estimated rotor current in stator reference frame and the sensed rotor current, are prone to measurement noise. On the other hand, the schemes, which use rotor back-emf integration, are affected by DC drift problems, though they are not much affected by measurement noise. The proposed stator flux position estimation scheme incorporates the benefits obtained from both the above schemes while eliminating the disadvantages inherent to them. The rotor flux position is estimated by integrating the rotor back-electromotive force. The stator flux is then obtained from the rotor flux estimate. This integration mechanism leads to several problems like dc drift and lack of error decaying mechanism. This estimation scheme solves the above problems including reduction in the propagation of noise in the sensed current to the estimated rotor side unit vectors. On the implementation front, this scheme also eliminates the need for differentiating the unit vectors for estimating slip frequency. This makes the proposed flux estimator very robust. The proposed scheme is simulated and experimentally verified. There is an internal DC bus within the proposed power conditioner that manages the energy flow through the three energy ports. The internal DC bus is interfaced to an external accumulator or battery through a power interface called the multi phase bi-directional dc-dc converter. It is generally advantageous to have the motor rated for higher voltages in order to achieve better efficiencies for a given power rating as compared to low voltage motors. This implies higher DC bus voltage. On the other hand, it is advantageous to have the battery bank rated for low voltage in order to improve the volumetric efficiency which is better at lower battery bank voltages. Both these are contradictory requirements. The above problem is solved in this thesis by proposing a multi power port topology using a bidirectional fly-back converter that is capable of handling multiple power sources and still maintain simplicity and features like high gain, wide load variations and lower output current ripple. As a spin-off, the scheme can handle parallel energy transfer from even a eutectic combination of batteries without any additional control circuitry for parallel operation. Further, the scheme also incorporates a novel transformer winding technique which significantly reduces the leakage inductance of the coupled inductor. The proposed multi-port bidirectional converter is analyzed by including non-idealities like leakage inductance. The DC bus voltage regulation requirement is not very stringent because it is not directly fed to any load. Therefore, hysteresis voltage regulation with small proportional correction is used for DC bus voltage control. The proposed converter is built and experimentally verified in the proposed system as well as in a hybrid-electric vehicle prototype. The third port of the proposed power conditioner interfaces with the stator of the SRIM and the load. The stator/load needs to be connected to a stiff micro-grid. The control requirement of the micro-grid is very stringent because, even for a sudden variation in the wind speed or the load, the grid voltage magnitude and frequency should not change. The dynamic response of the grid voltage controller has to be very fast. Moreover, the grid voltage must be balanced in presence of unbalanced loading. This thesis proposes a converter called the stator side converter along with three phase L-C filter at its output to form the micro-grid. A generalized control scheme is proposed wherein the negative sequence components and the harmonics can be eliminated at the micro-grid by means of feed-forward compensators included in the fundamental positive synchronous reference frame alone. The theoretical foundation for this scheme is developed and discussed in the thesis. In isolated locations linear loads constitute a significant percentage of the total load. Therefore, on the implementation front, only the compensation of fundamental negative sequence is demonstrated. One more necessity for compensating the fundamental negative sequence is that, the SRIM offers only leakage impedance to the fundamental negative sequence components resulting in high fundamental negative sequence current even for a small fundamental negative sequence voltage present at the micro-grid. The proposed scheme ensures balanced three phase currents at the SRIM windings and the full unbalanced current is provided from the stator side converter. This scheme is validated both by simulation and experimentation. The proposed power conditioner is integrated and used in the implementation of the entire wind power generation scheme that is proposed in the thesis. The maximum power point tracking of the wind power unit is also incorporated in the proposed system. The simulation and experimental results are also presented. Finally, the engineering issues involved in the implementation of the proposed scheme are discussed in detail highlighting the hardware configuration and the equipments used. The wind turbine is emulated using a chopper controlled DC motor. The shaft torque of the DC motor is controlled to give the Cp−λ characteristic of a typical windmill. The control issues of the DC machine to behave as a wind turbine are also explained. Finally the thesis is concluded by a statement of potentials and possibilities for future work in this research area.

Nowadays, the number of applications which need more than one power source is increasing. Distributed generating systems or micro-grid systems normally use more than one power source or more than one kind of energy source. Also, to increase the utilization of renewable energy sources, diversified energy source combination is recommended. For example, a wind-photovoltaic generating system, a combination of a wind generator and photovoltaic array, can give a greater degree of freedom when choosing the install location. The combination of more power sources and diversified power sources makes it possible to obtain higher availability in a power system. A parallel connection of converters has been used to integrate more than one energy source in a power system. However, a multiple-input converter (MIC) can generally have the following advantages compare to a combination of several individual converters; (1) cost reduction, (2) compactness, (3) more expandability and (4) greater manageability. First, this research suggests MIC topology comparison criteria that can be used as a decision guide for choosing a MIC topology depending on the application. Even though there are some MIC topology classification methods such as by the kind of combining methods, the classification methods are not enough to choose one particular topology. The comparison criteria presented in this dissertation are practical enough to decide which topology is suitable and should be chosen. Second, a new MI modified inverse Watkins-Johnson converter (MIMIWJC) without a coupled inductor is proposed. The circuit configuration of this converter and its operation principles are described, including the open-loop and closed-loop circuit. For control purposes, a small signal model of the proposed converter is developed using Middlebrook’s extra element theorem. In addition, two possible control methods are introduced in this dissertation. Finally, the theoretical analysis of the proposed converter is verified with simulations and experiments. / text

This thesis presents a supervisory hybrid controller for the automatic operation and control of a wind energy conversion and battery storage system. The supervisory hybrid control scheme is based on a radically different approach of modeling and control design, proposed for the subject wind energy conversion and battery storage system. The wind energy conversion unit is composed of a 360kW horizontal axis wind turbine mechanically coupled to an induction generator through a gearbox. The assembly is electrically interfaced to the dc bus through a thyristor-controlled rectifier to enable variable speed operation of the unit. Static capacitor banks have been used to meet reactive power requirements of the unit. A battery storage device is connected to the dc bus through a dc-dc converter to support operation of the wind energy conversion unit during islanded conditions. Islanding is assumed to occur when the tiebreaker to the utility feeder is in open position. The wind energy conversion unit and battery storage system is interfaced to the utility grid at the point of common coupling through a 25km long, 13.8kV feeder using a voltage-sourced converter unit. A bank of static (constant impedance) and dynamic (induction motor) loads is connected to the point of common coupling through a step down transformer. A finite hybrid-automata based model of the wind energy conversion and storage system has been proposed that captures the different operating regimes of the system during grid-connected and in islanded operating modes. The hybrid model of the subject system defines allowable operating states and predefines the transition paths between these operating states. A modular control design approach has been adapted in which the wind energy conversion and storage system has been partitioned along the dc bus into three independent system modules. Traditional control schemes using linear proportional-plus-integral compensators have been used for each system module with suitable modifications where necessary in order to achieve the required steady state and transient performance objectives. A supervisory control layer has been used to combine and configure control schemes of the three system modules to suite the requirements of system operation during any one operating state depicted by the hybrid model of the system. Transition management strategies have been devised and implemented through the supervisory control layer to ensure smooth inter-state transitions and bumpless switching among controllers. It has been concluded based on frequency domain linear analysis and time domain electromagnetic transient simulations that the proposed supervisory hybrid controller is capable of operating the wind energy conversion and storage system in both grid-connected and in islanded modes under changing operating conditions including temporary faults on the utility grid.

This thesis presents a supervisory hybrid controller for the automatic operation and control of a wind energy conversion and battery storage system. The supervisory hybrid control scheme is based on a radically different approach of modeling and control design, proposed for the subject wind energy conversion and battery storage system. The wind energy conversion unit is composed of a 360kW horizontal axis wind turbine mechanically coupled to an induction generator through a gearbox. The assembly is electrically interfaced to the dc bus through a thyristor-controlled rectifier to enable variable speed operation of the unit. Static capacitor banks have been used to meet reactive power requirements of the unit. A battery storage device is connected to the dc bus through a dc-dc converter to support operation of the wind energy conversion unit during islanded conditions. Islanding is assumed to occur when the tiebreaker to the utility feeder is in open position. The wind energy conversion unit and battery storage system is interfaced to the utility grid at the point of common coupling through a 25km long, 13.8kV feeder using a voltage-sourced converter unit. A bank of static (constant impedance) and dynamic (induction motor) loads is connected to the point of common coupling through a step down transformer. A finite hybrid-automata based model of the wind energy conversion and storage system has been proposed that captures the different operating regimes of the system during grid-connected and in islanded operating modes. The hybrid model of the subject system defines allowable operating states and predefines the transition paths between these operating states. A modular control design approach has been adapted in which the wind energy conversion and storage system has been partitioned along the dc bus into three independent system modules. Traditional control schemes using linear proportional-plus-integral compensators have been used for each system module with suitable modifications where necessary in order to achieve the required steady state and transient performance objectives. A supervisory control layer has been used to combine and configure control schemes of the three system modules to suite the requirements of system operation during any one operating state depicted by the hybrid model of the system. Transition management strategies have been devised and implemented through the supervisory control layer to ensure smooth inter-state transitions and bumpless switching among controllers. It has been concluded based on frequency domain linear analysis and time domain electromagnetic transient simulations that the proposed supervisory hybrid controller is capable of operating the wind energy conversion and storage system in both grid-connected and in islanded modes under changing operating conditions including temporary faults on the utility grid.