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Fumo, Nelson. "COOLING, HEATING, AND POWER SYSTEMS ENERGY PERFORMANCE AND NON-CONVENTIONAL EVALUATION BASED ON ENERGY USE." MSSTATE, 2008. http://sun.library.msstate.edu/ETD-db/theses/available/etd-06062008-120919/.
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Cooling, Heating and Power (CHP) systems have been recognized as a key alternative for thermal energy and electricity generation at or near end-user sites. CHP systems can provide electricity while recovering waste heat to be used for space and water heating, and for space cooling. Although CHP technology seems to be economically feasible, because of the constant fluctuations in energy prices, CHP systems cannot always guarantee economic savings. However, a well-designed CHP system can guarantee energy savings, which makes necessary the quantification of non-conventional benefits from this technology in order to offset any economic weakness that can arise as consequence of energy prices. Some aspects that could be included in a non-conventional evaluation are: building energy rating, emission of pollutants, power reliability, power quality, fuel flexibility, brand and marketing benefits, protection from electric rate hikes, and benefits from promoting energy management practices. This study focuses on two aspects: building energy rating and emission reduction of pollutants, related to CHP system energy performance. Two methodologies have been developed in order to estimate the energy related benefits from CHP technology. To determine the energy performance, a model has been developed and implemented to simulate CHP systems in order to estimate the building-CHP system energy consumption. The developed model includes the relevant variables governing CHP systems such as: type and size of the components, individual component efficiencies, system operating mode, operational strategy, and building demand for power, heating, and cooling. The novelty of this model is the introduction of the Building Primary Energy Ratio (BPER) as a parameter to implement a primary energy operational strategy, which allows obtaining the best energy performance from the building-CHP system. Results show that the BPER operational strategy always guarantees energy savings. On the other hand, results from a cost-oriented operational strategy reveal that for critical design conditions, high economic savings can be obtained with unacceptable increment of energy consumption. For Energy Star Rating and Leadership in Energy and Environmental Design (LEED) Rating, results show that CHP systems have the ability to improve both ratings.
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Lipana, Catherine H. "When incentives are not enough : a study on how the Philippine government can attract foreign investments in renewable power /." Bergen : Norges Handelshøyskole, 2008. http://bora.nhh.no:8080/bitstream/2330/2118/1/Lipana%202008.pdf.
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Piedrafita, Francos Daniel. "Designing, testing and modelling two innovative non-conventional buckling restrained braces for seismic resistant buildings." Doctoral thesis, Universitat de Girona, 2014. http://hdl.handle.net/10803/284738.
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In this thesis two all-steel BRB have been designed, manufactured and tested, and both satisfy the testing protocols required by EU and US codes. They are composed of a steel slotted restraining unit which stabilizes the steel core. The first one, the Modular Buckling Restrained Brace (MBRB), is composed by several seriated modules which contain several dissipation units connected in parallel, which yield under shear forces. Although it has good hysteretic response and a high ductility, its core is heavy and expensive to manufacture. The second one,the Slotted Buckling Restraining Brace (SBRB), solves these two shortcomings. It yields under axial forces, like the conventional BRBs, but the usual solid core has been substituted by a perforated plate. The core is a one-piece element composed of two lateral bands, of a nearly uniform section and designed to yield, connected by stabilizing bridges, which behave elastic. The buckling prevention of the lateral bands is done by the restraining unit and the stabilizing bridges. Design expressions have been proposed to design both devices, and a numerical material model have been formulated and implemented in commercial finite element method software to numerically simulate the behavior of the braces, which will reduce the need of full scale tests for its designEn la present tesi, dos BVR totalment metàl·lics s’han dissenyat, fabricat i assajat, satisfent tots dos els requeriments dels protocols definits per les normes europees i americanes. Estan formats per un element de travat ranurat que estabilitza el nucli metàl·lic. El primer d’ells, el Braç de Vinclament Restringit Modular (BVRM), està format per diversos mòduls seriats que a la vegada contenen diverses unitats de dissipació, que plastifiquen sota esforços tallants, connectades en paral·lel. Tot i que té un bon comportament histerètic i una gran ductilitat, el nucli és pesat i difícil de fabricar. El segon braç, anomenat Braç de Vinclament Restringit Ranurat (BVRR), soluciona aquests inconvenients. Plastifica sota esforços axials, de la mateixa manera que els BVR convencionals, però el nucli massís és substituït per una platina perforada. Aquest nucli consisteix en un únic element composat per dos bandes laterals, dissenyades per a plastificar i amb una secció quasi constant, connectades per diversos ponts estabilitzadors que es mantenen sempre en el seu rang elàstic. Aquests ponts, juntament amb l’element de travat, impedeixen el vinclament de les bandes laterals. S’han proposat diverses expressions de disseny pels dos braços. S’ha formulat i implementat, en un programa d’elements finits comercial, un model de material per a simular numèricament el comportament dels braços, reduint així la dependència dels assajos a escala real durant el seu procés de disseny
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De, Silva Tharukara Sudath Priyantha. "Develop strategies to increase the Non Conventional Renewable Energy power generation in Sri Lanka above 10% level by the year 2015." Thesis, KTH, Energi och klimatstudier, ECS, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-109768.
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World’s energy needs are increasing day by day and meeting that ever increasing demand by fossil fuels is becoming difficult due to factors like scarcity of the resource, vulnerability of supply due to political unrest of fuel rich countries, and environmental implications of usage. As a result, Usage of renewable energy resources as alternatives is becoming popular and important. Sri Lanka has already committed to achieve 10% of grid connected electricity energy from Non Conventional Renewable Energy sources by the year 2015 and launched many programs to support that initiative. Under this dissertation, a broad study on present and future electricity generation and transmission network of Sri Lanka are carried out referring the most recent CEB publications like Long Term Generation Expansion Plan and Transmission Expansion plans and further using the expert opinions. Special attention is given to calculate present and future (2015) Non Conventional Renewable Energy share of power generation considering the constraints and mentioning the assumptions. Existing policies to promote NCRE power generation are reviewed while discussing the barriers. Wind has identified as the viable potential candidate as future NCRE power generation option even though the near term capacity is limited due to grid constraints and inadequate transmission and distribution network. It is recommended to the government to start an accelerated wind power harness program by addressing the issues pertaining to the technology. The strategies developed under the study are all about to achieve more than 10% target by the year 2015.
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Sehar, Fakeha. "Impact of Ice Storage on Electrical Energy Consumption in Large and Medium-sized Office Buildings in Different Climate Zones." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/35291.
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Cooling demand constitutes a large portion of total electrical demand for office buildings during peak hours. Deteriorating load factors, increased use of more inefficient and polluting peaking units are the aftermaths of growth in peak demand challenging energy system efficiency and grid reliability.
Ice storage technology can help shift this peak cooling demand to off-peak periods. Ice storage reduces or even eliminates chiller operation during peak periods. The objective of the research is to analyze the chiller energy consumption of conventional non-storage and ice storage cooling systems for large and medium-sized office buildings in diverse climate zones. The research also quantifies the peak energy savings as a result of ice storage systems.
To accomplish the thesis objectives the Demand Response Quick Assessment Tool (DRQAT) has been used to model and simulate large and medium-sized office buildings in diverse climate zones with non-storage and ice storage cooling systems. Demand Response Quick Assessment Tool (DRQAT) has been developed by LBNLâ s Demand Response Research Center. It is based on the most popular features and capabilities of EnergyPlus and is downloadable from [1]. The construction and weather files in DRQAT have been modified to incorporate construction standards and weather data for the cities representing the diverse climate zones. The ice storage systemâ s operating and control strategies investigated include full storage and partial storage with storage priority and chiller priority.
Research findings indicate that chiller energy consumption for non-storage and ice storage systems depends highly on climatic conditions. The climate zones with hot summers as well as small day and night temperature variations show higher chiller energy consumption. The marine climate zone has the lowest chiller energy consumption. The cold/humid climate zone has higher chiller energy consumption than the cold/dry and very cold climate zones. The cold/dry and very cold climate zones have comparable chiller energy consumption. The research findings will help utilities and building owners to quantify the benefits of installing ice storage systems in office buildings located in different climate zones.Master of Science
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Oliveira, Eduardo Sylvestre Lopes de. "Projeto, construção, simulação, implementação e testes de um gerador a relutância chaveada monofásico." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/18/18153/tde-08082011-164853/.
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O objetivo do trabalho é apresentar o funcionamento de um gerador a relutância chaveado monofásico. Para isso, foi desenvolvido um modelo computacional em ambiente Matlab Simulink, fazendo-se a comunicação entre diferentes partes do sistema. O comportamento da dinâmica de geração é apresentado para diferentes pontos do sistema, e testes experimentais realizados em um pequeno protótipo confirmam as características funcionais desta máquina. Ensaios realizados comprovam sua funcionalidade e simplicidade de operação, tendo estabilidade de geração para ampla faixa de velocidade de funcionamento, caracterizando uma máquina promissora, robusta e eficiente para aplicações especiais.This work presents a single-phase switched reluctance machine operating as a generator. For that purpose, a computational model was developed in Matlab Simulink environment, wherein all the system components, such as voltage source, drive and machine model, and load were integrated. The current and voltage behavior for several points of operations are presented. Furthermore, experimental tests were also carried out in a simple prototype to validate its functionality and simplicity of operation, providing a stable power generation over a wide range of speed. The results showed that the single-phase switched reluctance generator can be robust, efficient, and promising for especial applications.
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Kunstmann, Martin. "Comparative LCA of Wood from Conventional Forestry and Wood from Short Rotation Coppice." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-135927.
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Worldwide there is an increasing demand of natural resources. In future, non renewable resources get substituted by renewable resources in the energetic sector as well as in the material sector. That implies a stronger usage of renewable resources especially - wood. In 2009 there was a usage of 77 million cubic meters of wood for material applications and a quantity of 55 million cubic meters for energetic applications in Germany alone. Furthermore, there is an increasing demand on wood for energetic purposes. In 2007 this problematic development led to the first supply bottlenecks. To meet the increasing demands of the future, Short Rotation Coppices (SRC) can help to improve the wood provision.
An SRC is a planting of fast growing coppice on agricultural areas, which is managed more intensively than usual forestry practices for a quicker production of wooden biomass. With a comparative LCA of conventional wood and wood from SRC the present study evaluates if wood from SRC is reasonable to cover the increasing demand of wood for material and energetic purposes in an environmental friendly way. A comprehensive literature research regarding LCAs of wood and wooden products shows that there are no previous studies comparing the two types of wood. Hence, the present study examines a particleboard production as the material scenario and the combustion of woodchips in a firing system as the energetic scenario to compare the ecological advantages and disadvantages of wood from SRC and conventional wood. The LCA is implemented with the Gabi software designed by PE International. Data is obtained from previous LCA studies evaluating the production of wood, the particleboard production and the combustion of wood.
Additionally, data from the Ecoinvent database is used. Functional units are the production of 1m3 particleboard and the production of 1 MJ of thermal energy. The LCIA is implemented with the “Ecoindicator” as endpoint- and “CML 2001” as midpoint approach to cover broad range of environmental issues. Moreover a sensitivity analyses shows the impact of decisive variables on the results of “Ecoindicator” and “CML 2001”.
Results reveal that outcomes of the LCIA are dependent of the assessment method and the processed part of trees from conventional forestry. The present study shows, that with an efficient land use, wood from SRC can help to cover the increasing demand of wood for material and energetic purposes in a sustainable way. However, an immediate usage of wood for energetic purposes has to be seen critical. Instead, a cascaded and sustainable utilization of wood is recommendable to counteract climate change and to improve the efficient use of the renew-able resource - “wood”.
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Le, Minh Thong. "Le rôle des gaz conventionnels et non-conventionnels dans la transition énergétique en Asie." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAE007/document.
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Les problématiques de l’énergie et de l’environnement sont un des principaux défis pour l’humanité au XXIème siècle. La croissance mondiale de la demande d’énergie est confrontée aux préoccupations environnementales (y compris la pollution, le réchauffement climatique et la réduction des émissions de CO2), en particulier dans les régions en croissance économique rapide comme l’Asie. Le transfert de l’utilisation des sources d’énergies traditionnelles comme le charbon, le pétrole, vers les sources d’énergie plus propres et des énergies renouvelables est une tendance inévitable à l’avenir. Dans le contexte actuel, le gaz naturel est considéré comme une source d’énergie propre qui jouera un rôle important dans le processus de transition énergétique vers une économie bas-carbone. Les conséquences pour les marchés de gaz naturel peuvent être considérables. La condition d’une telle évolution est de disposer d’une offre en gaz naturel importante. Le développement du gaz non conventionnel, en particulier le gaz de schiste, fournit une opportunité d’expansion de l’approvisionnement gazier mondial comme le montre la « révolution du gaz de schiste » aux États- Unis. Celle-ci a profondément modifié les marchés gaziers régionaux. Toutefois, cette « révolution » n’est guère reproductible à d’autres régions du monde. Cette thèse démontre en particulier qu’en dehors des facteurs géologiques, des conditions institutionnelles (fiscalité, droits de propriété), économiques (prix, technologies) et organisationnelles (libéralisation des marchés) sont nécessaires pour assurer un développement à grande échelle des ressources non conventionnelles. Cette thèse montre que ces conditions ne sont pour la plupart pas réunies ni en Europe ni en Asie (notamment en Chine). Dès lors, une transition par le gaz pour répondre aux enjeux climatiques en Asie se fera par la voie des importations et non par une production propre à la région. A partir de trois scénarios du modèle POLES basés sur des hypothèses de politique climatique, de développement du gaz de schiste et d’augmentation rapide de la demande de gaz dans le mix énergétique, en particulier en Asie, deux principales conclusions émergent. Tout d’abord, l’importance du développement des gaz de schistes aux USA, leur bas coût de production induisent au niveau mondial une offre de gaz abondante et compétitive par rapport à d’autres énergies notamment par rapport au charbon. Par conséquent, même sans politique climatique, les conditions sont réunies pour que la part du gaz naturel puisse croître dans le mix énergétique. Deuxièmement, une politique climatique affirmée a des effets contradictoires quant à l’importance du gaz naturel dans les mix énergétiques des pays asiatiques. D’un côté elle permet une pénétration plus importante du gaz naturel dans leur mix énergétique. Mais dans le même temps, limitant la demande d’énergie, les volumes de gaz naturel demandés ne sont que légèrement plus importants que dans des scénarios sans politique climatiqueEnergy and environmental issues are one of the main challenges for humanity in the 21st century. Global growth in energy demand links to environmental concerns including pollution, global warming and reduction of CO2 emissions. In particular, it is an urgent request in rapidly growing developing regions such as Asian countries. Using cleaner energy sources, renewable energy instead of traditional energy sources like coal and oil is an inevitable option in the future. In the current context, natural gas is seen as a clean energy source which plays a major role in the energy transition process towards a low-carbon economy. The consequences for natural gas markets are significant and the condition of this change is an abundant supply of natural gas. The development of unconventional gas, particularly shale gas, provides an opportunity to expand the global gas supply. This is illustrated by the “shale gas revolution” in US which has profoundly changed the regional gas markets. However, this "revolution" is hardly reproducible in other regions of the world. This thesis demonstrates particularly that apart from geological, institutional conditions (taxation, property rights), economic (prices, technologies) and organizational (free markets) are necessary for a large scale development of unconventional resources. This research also shows that most of these conditions are not met in Europe or Asia (especially in China). Therefore, an energy transition by natural gas to meet climate challenges in Asia will be solved through imports, rather than through regional production. From three scenarios of the POLES model based on assumptions about climate policy, shale gas development and rapid increase of demand for gas in the energy mix (particularly in Asia), two main conclusions emerge. The developments of shale gas with low cost in the USA make the global gas supply abundant and more competitive than other energies, particularly coal. Therefore, even without climate policy, the conditions are ripe for the increaseof natural gas proportion in the energy mix. Secondly, a strong climate policy has contradictory effects on the relative share of natural gas in the Asian energy mix. On the one hand, it allows natural gas larger penetration into the energy mix of Asia. But at the same time, with limitation of energy demand, requested natural gas volumes are only slightly higher than in scenarios without climate policy
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McRae, Peter. "Unaccountable Soldiers: Private Military Companies and the Law of Armed Conflict." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/20580.
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The use of Private Military Companies (PMCs) has become an increasingly common feature of contemporary armed conflict. Because of their autonomous contractual status, PMCs have presented governments with problems of accountability on several levels, including violations of international human rights and humanitarian law (IHL) standards. This thesis argues that PMCs should be considered to be non-state actors (NSAs), subject to international law from both an International Relations Theory and a Legal Theory perspective. This conclusion is linked to the issue of whether individual PMC employees can be treated as legitimate combatants according to IHL. State practice has not led to a clear understanding of the definition of combatant, a problem which has been compounded by a lack of government policy on the use of PMCs. Using Canadian experience as a case study, the thesis concludes that IHL suggests two options for regularizing the status of PMCs which would both strengthen accountability and uphold the rule of law.
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El, Jadie Amna. "L'énergie nucléaire et le droit international public." Thesis, Tours, 2017. http://www.theses.fr/2017TOUR1006/document.
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Tous les États sans discrimination ont un droit inaliénable de développer les utilisations de l'énergie nucléaire à des fins civiles, à condition de ne pas détourner ces utilisations pacifiques vers des armes nucléaires. Cependant, il est accordé à cinq pays le droit de posséder ces armes, à savoir les États-Unis, la France, la Russie, la Chine et le Royaume-Uni. Autour de cette position, un vif débat à la fois juridique et éthique a été soulevé. En effet, pour ses opposants, le nucléaire représente un risque durable et non maîtrisable par la science. Les accidents nucléaires majeurs, les déchets radioactifs et le détournement du nucléaire à des fins militaires sont des risques ingérables et d‟une gravité exceptionnelle. En revanche, les défenseurs de cette énergie la présentent comme sûre, voire partie prenante du développement durable. Selon eux, le nucléaire est un moyen fiable de lutter contre le réchauffement climatique et aussi une solution à la pénurie énergétique à laquelle le monde est confronté. En examinant et analysant la fiabilité et la crédibilité de tous les arguments allant à l‟encontre et en faveur de cette industrie, on constate que la licéité et la légitimité du recours à l'énergie nucléaire sont mal fondées. Par conséquent, nous estimons qu‟il est nécessaire de dépasser le nucléaire par la conclusion d'une convention internationale posant l'interdiction progressive mais complète du nucléaireAll states without discrimination have an inalienable right to develop the uses of nuclear energy for civilian purposes, provided they do not divert these peaceful uses to nuclear weapons. However, five states have been granted the right to possess these weapons, that is : United-States, France, Russia, China and United-Kingdom. Around this position a fierce debate, both legal and ethical, has been raised. Indeed for its opponents nuclear represents a persistent risk that is non controllable by science. Major nuclear accidents, radioactive wastes and the use of nuclear for military purposes are unmanageable risks of exceptionnal serious gravity. On the other hand, the proponents of this energy present it as safe, even as part of sustainable development. According to them, nuclear is a reliable means to fight global warming and is also a solution to the energy shortage the world is facing. When analyzing the reliability and the credibility of all arguments for and against this industry, it can be noticed that the lawfulness and legitimacy of the use of nuclear energy are ill-founded. Therefore, we believe there is a need to go beyond nuclear with the conclusion of an international convention dealing with the progressive but comprehensive nuclear ban
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Mallangi, Siva Sai Reddy. "Low-Power Policies Based on DVFS for the MUSEIC v2 System-on-Chip." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-229443.
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Multi functional health monitoring wearable devices are quite prominent these days. Usually these devices are battery-operated and consequently are limited by their battery life (from few hours to a few weeks depending on the application). Of late, it was realized that these devices, which are currently being operated at fixed voltage and frequency, are capable of operating at multiple voltages and frequencies. By switching these voltages and frequencies to lower values based upon power requirements, these devices can achieve tremendous benefits in the form of energy savings. Dynamic Voltage and Frequency Scaling (DVFS) techniques have proven to be handy in this situation for an efficient trade-off between energy and timely behavior. Within imec, wearable devices make use of the indigenously developed MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). This system is optimized for efficient and accurate collection, processing, and transfer of data from multiple (health) sensors. MUSEIC v2 has limited means in controlling the voltage and frequency dynamically. In this thesis we explore how traditional DVFS techniques can be applied to the MUSEIC v2. Experiments were conducted to find out the optimum power modes to efficiently operate and also to scale up-down the supply voltage and frequency. Considering the overhead caused when switching voltage and frequency, transition analysis was also done. Real-time and non real-time benchmarks were implemented based on these techniques and their performance results were obtained and analyzed. In this process, several state of the art scheduling algorithms and scaling techniques were reviewed in identifying a suitable technique. Using our proposed scaling technique implementation, we have achieved 86.95% power reduction in average, in contrast to the conventional way of the MUSEIC v2 chip’s processor operating at a fixed voltage and frequency. Techniques that include light sleep and deep sleep mode were also studied and implemented, which tested the system’s capability in accommodating Dynamic Power Management (DPM) techniques that can achieve greater benefits. A novel approach for implementing the deep sleep mechanism was also proposed and found that it can obtain up to 71.54% power savings, when compared to a traditional way of executing deep sleep mode.Nuförtiden så har multifunktionella bärbara hälsoenheter fått en betydande roll. Dessa enheter drivs vanligtvis av batterier och är därför begränsade av batteritiden (från ett par timmar till ett par veckor beroende på tillämpningen). På senaste tiden har det framkommit att dessa enheter som används vid en fast spänning och frekvens kan användas vid flera spänningar och frekvenser. Genom att byta till lägre spänning och frekvens på grund av effektbehov så kan enheterna få enorma fördelar när det kommer till energibesparing. Dynamisk skalning av spänning och frekvens-tekniker (såkallad Dynamic Voltage and Frequency Scaling, DVFS) har visat sig vara användbara i detta sammanhang för en effektiv avvägning mellan energi och beteende. Hos Imec så använder sig bärbara enheter av den internt utvecklade MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). Systemet är optimerat för effektiv och korrekt insamling, bearbetning och överföring av data från flera (hälso) sensorer. MUSEIC v2 har begränsad möjlighet att styra spänningen och frekvensen dynamiskt. I detta examensarbete undersöker vi hur traditionella DVFS-tekniker kan appliceras på MUSEIC v2. Experiment utfördes för att ta reda på de optimala effektlägena och för att effektivt kunna styra och även skala upp matningsspänningen och frekvensen. Eftersom att ”overhead” skapades vid växling av spänning och frekvens gjordes också en övergångsanalys. Realtidsoch icke-realtidskalkyler genomfördes baserat på dessa tekniker och resultaten sammanställdes och analyserades. I denna process granskades flera toppmoderna schemaläggningsalgoritmer och skalningstekniker för att hitta en lämplig teknik. Genom att använda vår föreslagna skalningsteknikimplementering har vi uppnått 86,95% effektreduktion i jämförelse med det konventionella sättet att MUSEIC v2-chipets processor arbetar med en fast spänning och frekvens. Tekniker som inkluderar lätt sömn och djupt sömnläge studerades och implementerades, vilket testade systemets förmåga att tillgodose DPM-tekniker (Dynamic Power Management) som kan uppnå ännu större fördelar. En ny metod för att genomföra den djupa sömnmekanismen föreslogs också och enligt erhållna resultat så kan den ge upp till 71,54% lägre energiförbrukning jämfört med det traditionella sättet att implementera djupt sömnläge.
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Singh, Naval. "Non-Conventional Energy Sources." Thesis, 2009. http://ethesis.nitrkl.ac.in/218/1/Thesis.pdf.
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While fossil fuels will be the main fuels for thermal power, there is fear that they will get exhausted eventually in this century. Therefore other systems based on non-conventional and renewable sources are being tried by many countries. These are solar, wind, sea, geothermal and biomass. After making a detailed preliminary analysis of biomass energy, geothermal energy, ocean thermal energy, tidal energy and wind energy, I focused mainly on Wind power for 7th semester. In wind power, I have studied mechanical design of various types of wind turbines, their merits, demerits and applications, isolated and grid-connected wind energy systems with special attention to power quality. In the end I wrote, compiled and successfully executed a MATLAB program to assess the impact of a wind farm on the power system.
Solar radiation represents the earth’s most abundant energy source. This energy resource has a number of characteristics that make it a very desirable option for utilization. The perennial source of solar energy provides unlimited supply, has no negative impact on the environment, is distributed everywhere, and is available freely. In India, the annual solar radiation is about 5 kWh/m2 per day; with about 2300-3200 sunshine hours per year.
Solar energy can be exploited for meeting the ever-increasing requirement of energy in our country. Its suitability for decentralized applications and its environment-friendly nature make it an attractive option to supplement the energy supply from other sources. In 8th Semester, I have made an attempt to study the ways through which solar energy can be harnessed and stored. I have also written MATLAB program to evaluate performance of fuel cell.
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Joshi, Mahendra Chandra. "Control & Energy Management of Battery/Ultracapacitor Based Hybrid Energy Storage System." Thesis, 2019. http://ethesis.nitrkl.ac.in/10118/1/2019_PhD_MCJoshi_513EE1013_Control.pdf.
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The present research work deals with the control & energy management of battery & Ultracapacitor (UC) based Hybrid Energy Storage System (HESS). The proposed con-trol and energy management algorithms improve the system response and the HESS utilization. The efficiency, durability, and health of the HESS depend on control-ling the power flow of the HESS components subjected to their specified operational constraints. It is achieved by the Energy Management Algorithm (EMA). Power allo-cation is done by frequency sharing algorithm by allotting high-frequency components of load demand to UC and low-frequency components to the battery. An improved frequency sharing algorithm for battery/UC HESS in the presence of delay has been proposed in this work. The presence of the delay due to the digital implementation has been included in inner current control transfer functions for designing the PI con-troller. Initially, the PI controller parameters have been designed with phase margin and bandwidth specifications. The total time delay in the system varies and depends on the controller speed, and computational complexity and also, due to the presence of the unmodeled dynamics of the system, the stability and the performance of the system might be affected. Hence, to ensure system stability in the presence of de-lay, initially, the complete stabilizing set for inner PI controllers have been derived. Furthermore, the stabilizing set satisfying the specified frequency domain specifica-tions, i.e., phase margin and gain margin, have also been analytically derived and experimentally verified. As stated above, apart from frequency share-based power allocation, the EMA should also ensure proper operational constraints of the HESS components. In conventional EMAs, UC voltage is maintained at a nominal value by the UC voltage regulation loop, which reduces energy supplied by UC to the load during transients. This research proposes a filter based UC voltage control loop which eliminates the high-frequency components of UC charging current and hence reduces the conflict with DC-link voltage regulation loop. However, in UC voltage control loop based EMA’s, the UC operation remains restricted to a reference voltage to prevent it from overcharging/undercharging. This leads to a very narrow utilization of the UC voltage range. Since UC voltage can safely be varied from zero to its maximum rated voltage, therefore, rather than employing a UC voltage control loop, a time-share based approach has been proposed for UC charging/discharging. The proposed EMA operation depends on the defined UC voltage band instead of a UC reference voltage, which increases its power delivery capacity by approximately 2-4 times than the conventional EMAs. An experimental prototype of the system is designed, and the proposed control algorithm and EMA have been tested in the different operating regions for validation. The major contributions of the thesis can be summarized as: 1. Improved frequency sharing algorithm in the presence of delay.
2. The complete stabilizing set satisfying the desired phase margin and gain margin has been derived.
3. Filter based UC voltage control has been proposed.
4. Time-share based EMA has been proposed that improves UC utilization.
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Tiwari, Pusyakant, Dhananjaya Swain, and Anil Kumar Koppuravuri. "Study of Wind Energy System with Induction Generators." Thesis, 2011. http://ethesis.nitrkl.ac.in/2283/1/THESIS.pdf.
Full textAbstract:
Wind energy, as an alternative to fossil fuels, is plentiful, renewable, widely distributed, clean, and produces no greenhouse gas emissions during operation. The world has enormous resources of wind power. It has been estimated that even if 10% of raw wind potential could be put to use, all the electricity needs of the world would be met. A phased programme to develop wind energy in India started as early as 1985, and today the total installed capacity has reached 1650 MW, saving about 935,000 metric tonnes of coal.
Wind electrical generation systems are the most cost-competitive of all the environmentally clean and safe renewable energy sources in the world. They are also competitive with fossil fuel generated power and much cheaper than nuclear power.
Traditionally, wind generation systems used variable pitch constant speed wind turbines (horizontal or vertical axis) that were coupled to squirrel cage induction generators or wound-field synchronous generators and fed power to utility grids or autonomous loads.
The recent evolution of power semiconductors and variable frequency drives technology has aided the acceptance of variable speed generation systems. Such systems can yield 20-30% more power than constant-speed generation systems.
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Kumar, Ranjeet, and S. R. Sagiraju. "Harnessing of Wave Power from Horizontal Flow Dynamics of Shallow Waves." Thesis, 2009. http://ethesis.nitrkl.ac.in/300/1/PROJECT__RK_Sundar_final.pdf.
Full textAbstract:
Harnessing Ocean Wave power is a potential source of renewable form of energy. Our project was aimed at finding the constraints and proposing a suitable solution to utilize this form of energy. Ocean Wave Power is the most predictable, periodic and concentrated source among all renewable sources, but the constraints imposed on its harnessing are a result of its Ocean environment. Ocean wave dissipates energy in several strata of circular oscillation. But with depth induced water pressure these circular oscillation are squished into ellipse that approximates to back & forth motion. Statistically the horizontal oscillation shares the 68% of energy spectrum of wave energy. But due to irregular flow and variable pressure conventional hydropower harnessing techniques become improbable. In our project we have proposed a simple solution that takes the direct advantage of utilizing this energetic horizontal momentum of ocean waves, without in between conversion.
Our project works in parallel and in tandem with another group working on this project but deals with a different aspect of the problem. Our project has worked on finding the depth induced variation of distribution of ocean energy and maximum optimum depth for harnessing. The suitable components required for conversion from mechanical to electrical energy were analyzed. The slow rpm speed output needed attention for its conversion and Axial/Transverse Flux Permanent seemed to be the solution for our scenario.
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Gupta, Saurabh, and Rahul Shrivastava. "Study and Design of a Zero Voltage Switched Boost Converter." Thesis, 2009. http://ethesis.nitrkl.ac.in/1026/1/Project.pdf.
Full textAbstract:
We study theoretical circuit operation of zero voltage switching over the basic premise of boost converters (step-up dc chopper circuits). Zero-voltage switching technique is studied which, in contrast to zero-current switching, eliminates the switching loss and dv/dt noise due to the discharging of junction capacitances and the reverse recovery of diodes Zero Voltage Switching (ZVS) including various switching techniques in resonant converters is studied. Also a working model of a Zero Voltage Switched Boost Converter is constructed in the laboratory and its working and waveforms observed.
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Ghosh, S., and A. B. Swer. "Modelling of the Breakdown Voltage of Solid Insulating Materials using Soft Computing Techniques." Thesis, 2010. http://ethesis.nitrkl.ac.in/1972/1/btech_project_online.pdf.
Full textAbstract:
The aim of the project is to use Soft Computing Techniques (SCT) in order to model the breakdown voltage of solid insulating materials. Since the breakdown voltage behaviour is non-linear, it can be best modeled using SCT such as Artificial Neural Network (ANN), Radial Basis Function (RBF) Network, Fuzzy Logic (FL) Techniques etc. In order to obtain the experimental data on the breakdown voltage, experiments are conducted under AC and DC conditions and then all the SCT model are applied on it.
The prediction of the breakdown voltage of solid insulating materials is indeed a challenging task. Hence the best way to go about it is by resorting to SCT in order to model and predict the breakdown voltage.
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Behera, Smruti Ranjan, and Saroj Prasad. "Motoring and Generating mode of 3-Φ Induction Machine – A Comparative Evaluation For Energy Efficiency." Thesis, 2011. http://ethesis.nitrkl.ac.in/2612/1/Para.pdf.
Full textAbstract:
Vast use of fossil fuels is leading to energy deficiency. Hence the renewable energy sources like wind energy and solar energy are being used. Classical asynchronous induction generators are being used in wind energy based power generation system. In markets of micro electric energy generation unit system, induction generators are getting popularized, as it is cheap, robust and maintenance free. But generally induction machines are used as motor, hence the catalogues have only information about motoring mode. This report gives a comparative analysis between motoring and generating mode of induction machines. From this report we conclude that the induction motors have more efficiency and less losses than induction generators.
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Maria, Rosan, Debayan Chakraborty, and Sudeep Kumar Khuntia. "Modelling of Photovoltaic Water Pumping System using Frequency Control of Inverter." Thesis, 2012. http://ethesis.nitrkl.ac.in/3471/1/uploading_thesis.pdf.
Full textAbstract:
The depletion of fossil fuels and the increasing demand of energy have led to discovering new and supplement sources. In this direction the non conventional sources of energy have proved to be a great supplement. Not only that, few of these sources are the only solution to the power requirement where conventional power generation is not possible or its transmission from the source to that point is too costly. In such cases the power generation based on any of the non conventional source must be efficient to its maximum. In this project an application specific photovoltaic power generation system is designed along with a control mechanism which assists in extraction of increased power at any level of insolation than the normal mode of operation which includes constant frequency inverter operation. The primary use of PV system is usually in the process of water pumping for irrigation and other domestic application. Thus the system designed here is a “FREQUENCY CONTROL BASED WATER PUMPING SYSTEM”. The chief components of this system includes a PV array, a 3 Phase 180 degree mode voltage source inverter, a 3 phase induction motor and a centrifugal pump. Besides this there is a microprocessor based control block which sends the inverter the required control signal to help it track the maximum power. The complete project is based on the Simulink models and their simulation results which are expected to represent the real world components to the closest proximity.
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Ayenampudi, Praveen Varma, and Bala Chakri Kothuri. "Study Of Grid Connected Induction Generator for wind Power Applications." Thesis, 2012. http://ethesis.nitrkl.ac.in/3571/1/thesis.pdf.
Full textAbstract:
Over the past few decades, there has been an increasing use of induction generator particularly in wind power applications. In generator operation, a prime mover (turbine, engine) drives the rotor above the synchronous speed. Stator flux still induces currents in the rotor, but since the opposing rotor flux is now cutting the stator coils, active current is produced in stator coils, and motor now operates as a generator, and sends power back to the electrical grid. Based on the source of reactive power induction generators can be classified into two types namely standalone generator and Grid connected induction generator. In case of standalone IGs the magnetizing flux is established by a capacitor bank connected to the machine and in case of grid connection it draws magnetizing current from the grid.
This project explicitly deals with the study of grid connected induction generators where frequency and voltage of the machine will be dictated by the electric grid. Among these types of IGs, Doubly Fed Induction Generator (DFIG) wind turbines are nowadays increasingly used in large wind farms because of their ability to supply power at constant voltage and frequency. Modern control techniques such as Vector control and MFC (magnitude and frequency control) are studied and some of proposed systems are simulated in MATLAB-SIMULINK environment.
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Mishra, Bibek, and Bibhu Prasanna Kar. "Matlab based modeling of photovoltaic array characteristics." Thesis, 2012. http://ethesis.nitrkl.ac.in/3759/1/Untitled.pdf.
Full textAbstract:
Solar energy, radiant light and heat from the sun, has been reined by humans since ancient times using a range of ever-evolving technologies. Solar radiant energy accounts for most of the usable renewable energy on earth. Photovoltaic (PV) is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect. In this thesis, the PV array is modeled and its voltage-current characteristics and power-voltage characteristics are simulated and optimized. The main encumbrance for the reach of Photovoltaic systems is their low efficiency and high capital cost. Here we intend to examine a schematic to draw out maximum obtainable solar power from a PV module for use in a DC application. The concept of Maximum Power Point Tracking is to be implemented which results in appreciable increase in the efficiency of the Photovoltaic System. Different schemes of MPPT algorithms such as Perturb and Observe, Incremental Conductance, Fractional Open Circuit Voltage, Fractional Short Circuit Current, Fuzzy Logic Control, Neural Network are to be studied and implemented. The MPPT algorithm thus proposed will identify the suitable duty ratio in which the DC/DC converter should be operated to obtain maximum power output.
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Panda, S. K. "Reliable voltage monitoring system for synchronization of distributed power generation systems to utility grid." Thesis, 2014. http://ethesis.nitrkl.ac.in/6036/1/E-180.pdf.
Full textAbstract:
The unceasing progression of DPGS (Distributed Power Generation Systems) gives an effective and inexpensive approach, for electricity generation near by the consumer. Though for better performance, the distributed power generating stations are being allied to the utility network, there is an emergent necessity for the DPGS to work properly and uninterruptedly in case small grid instabilities. This needs developments to be made forthe control arrangement of DPGSs at the grid-side converter. As a consequence, grid interlinking necessities applied to distributed generations, are need to be continuously updated for maintaining the stability and the quality of the grid voltage. In the realm of grid interconnection, grid synchronization system is the main part of the control scheme of grid connected inverter. This is liable for extracting the phase angle of the grid voltage. One best technique, which is used today are phase-locked loops. From the beginning of the thesis a brief introduction about the distributed power generating stations is given. Later, voltage monitoring systems based on zero crossing detection (ZCD) to Phase Locked Loop (PLL) are given.A comprehensive survey aboutquadrature-signal generation, which is essential for three-phase and single-phase phase-locked-loop, is given. These QSG techniques are investigated and simulated in MATLAB-2010. Finally, thesis covers an advance synchronization approach in both three-phase and single-phasePLL with the inclusion of Second Order Generalized Integrator (SOGI). Both PLLs are experimentally verified by the use of LABVIEW-2010 with coalition with NI USB 6341
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Das, Kunal Kumar. "Development of Novel Techniques to Study Nonlinear Active Noise Control." Thesis, 2011. http://ethesis.nitrkl.ac.in/6657/1/PhD_Thesis_kunal_kumar_das.pdf.
Full textAbstract:
Active noise control has been a field of growing interest over the past few decades. The challenges thrown by active noise control have attracted the notice of the
scientific community to engage them in intense level of research. Cancellation of acoustic noise electronically in a simple and efficient way is the vital merit of the active noise control system. A detailed study about existing strategies for active noise control has been undertaken in the present work. This study has given an insight regarding various factors influencing performance of modern active noise control systems. The development of new training algorithms and structures for active noise control are active fields of research which are exploiting the benefits of different signal processing
and soft- computing techniques. The nonlinearity contributed by environment and various components of active noise control system greatly affects the ultimate
performance of an active noise canceller. This fact motivated to pursue the research work in developing novel architectures and algorithms to address the issues of nonlinear active noise control. One of the primary focus of the work is the application of artificial neural network to effectively combat the problem of active noise control. This is because artificial neural networks are inherently nonlinear processors and possesses capabilities of universal approximation and thus are well suited to exhibit high performance when used in nonlinear active noise control. The present work contributed significantly in designing efficient nonlinear active noise canceller based on neural network platform. Novel neural filtered-x least mean square and neural filtered-e least mean square algorithms are proposed for nonlinear active noise control taking into consideration the
nonlinear secondary path. Employing Legendre neural network led the development of a set new adaptive algorithms such as Legendre filtered-x least mean square, Legendre vi filtered-e least mean square, Legendre filtered-x recursive least square and fast Legendre filtered-x least mean square algorithms. The proposed algorithms outperformed the existing standard algorithms for nonlinear active noise control in terms of steady state mean square error with reduced computational complexity. Efficient frequency domain implementation of some the proposed algorithms have been undertaken to exploit its benefits. Exhaustive simulation studies carried out have established the efficacy of the proposed architectures and algorithms.
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Behera, Sudipta Kumar. "Multi-parametric Programming for Model Predictive Control." Thesis, 2015. http://ethesis.nitrkl.ac.in/7871/1/2015_MT_multi-paramatri_Behera.pdf.
Full textAbstract:
Model predictive control (MPC) solves a quadratic optimization problem to generate control law in each step. The usual methods of solution for quadratic optimization problem are interior point method, active set method etc. But most of the techniques are computationally heavy to perform the job in small amount of time. So a method is required where on-line computation is less. In multi-parametric quadratic programming (mp-QP) method an off-line computation is done a prior and a binary search tree is prepared. The on-line computation mainly involves a search through the binary-tree. The mp-QP is suitable for the class of optimization problem, where the objective function is to minimize or maximize a performance criterion subject to a given set of constraints where some of the parameter vary between lower and upper bounds. Also mp-QP is suitable for multi-objective optimization, where multi criteria problems can be reformulated as multi-parametric programming problems and a parametrized optimal solution is obtained. Multi-parametric programming is a technique for obtaining: (i) the objective and optimization variable as functions of the varying parameters and (ii) the regions in the space of the parameters where these functions are valid. The newly developed convex optimization solver CVXGEN is utilized successfully for off-line calculations which involves of dividing the parameter space into different polyhedral regions.In each one, the objective function has a constant value. The process involves another kind of optimization problem. For CVXGEN, worst case solving time is in milliseconds, even for a large problem.Thus, the use of CVXGEN minimizes the off-line calculation in mp-QP technique. In this work, an input constraint MPC problem is chosen from existing literature. The problem is solved for both two step prediction and three step prediction cases.The control input and states are ploted for both the MPC problems, and the results are compared.
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Mahapatra, Subhasish. "Nonlinear H∞ Control Algorithms for Autonomous Underwater Vehicle in Diving and Steering Planes." Thesis, 2018. http://ethesis.nitrkl.ac.in/9603/1/2018_phd_SMahapatra_513EE6017_Nonlinear.pdf.
Full textAbstract:
During the last decade, significant research has been directed on designing autonomous underwater vehicles (AUVs) for several applications including surveillance of specific
regions of a seafloor and underwater mine detection in defense applications, and scan-ning of pipelines and detection of leakages in oil/gas industries, etc. However, a number of issues arise in control of these AUVs such as control with autonomy, and commu-nication failure, etc., when underwater vehicles are deployed in underwater missions. Hence, there is a growing interest in developing control algorithms for underwater ve-hicles to address these issues. These mission control algorithms include appropriate
controllers for executing path following, trajectory tracking and point stabilization motion plans. These algorithms can be executed by designing suitable controllers for the diving and steering planes of AUVs in face of parametric uncertainties that occur in AUV dynamics (e.g. hydrodynamic coefficients and ocean currents). This thesis
focuses on designing a number of H∞ robust control algorithms for an AUV in both diving and steering planes. These robust control algorithms include designing of a
number of nonlinear H∞ control algorithms using techniques such as Taylor’s series approach, nonlinear matrix inequality (NLMI) approach and sum of square (SOS)
approach. In order to verify the efficacies of the proposed control algorithms, both simulation and experimentation were pursued. A prototype torpedo-shaped AUV is designed and developed in the laboratory. This prototype AUV is equipped with a computational module integrated with various
sensor, actuation, communication and power modules. Further, the computational unit of the developed AUV is installed with Robot Operating System (ROS) which is a software framework to integrate all the modules. The proposed nonlinear H∞ robust control algorithms are implemented using the computational unit of the prototype AUV to achieve desired diving and steering motion control objectives. The thesis first describes the development of nonlinear H∞ state feedback control algorithm using Taylor’s series approach for the diving and steering planes. In this ap-proach, the control problem is formulated as a Hamilton-Jacobi-Isaac (HJI) inequality which is obtained using dissipative theory which suggests that the input energy of a system is always greater or equal to the output energy. In this approach, the nonlinear AUV system together with the HJI inequality are transformed into Taylor’s series form with a specific order to synthesize a robust control algorithm. Then, this control
algorithm is synthesized using MATLAB/Simulink. This controller exhibits excellent tracking of the desired depths and desired yaw orientations by attenuating the distur-
bances with an improved L2 gain performance. Then, the robustness analysis of this controller is pursued to evaluate the controller performance against model uncertain-
ties. The experimental verification of the developed control algorithms is carried out in the swimming pool of National Institute of Technology Rourkela. It is observed during the controller synthesis that if the order of Taylor’s series increases, then the attenuation of disturbances also improves. However, the order of the controller struc-
ture also increases. Hence, to reduce the order of the control structure, less number of states are considered. Although this approach provides good performance during the
tracking desired depth and yaw profiles, this control algorithm is developed by considering a constant dissipative rate which yields a local solution that may not converge
to an analytical solution. In order to resolve the above issue, another nonlinear H∞ control algorithm is designed to obtain an optimal local solution that will converge to
a local analytical solution using nonlinear matrix inequality (NLMI) approach. The NLMI approach for designing the nonlinear H∞ control algorithm is used to achieve both diving and steering motion of the AUV. In this approach, the HJI inequality is transformed into state dependent LMIs which are solved to obtain the control laws for diving and steering planes of AUV. The controller is intended to track
the desired depth and yaw profiles by achieving the L2 gain performance. Similarly, the robustness of the NLMI based control algorithm is verified in presence of model
uncertainties. Also, the effectiveness of the control algorithm is verified experimentally. However, if the number of states increases, then this algorithm yields conservative
results. As discussed earlier in Taylor’s series approach, this NLMI based approach also provides a local solution for a constant dissipative rate. However, if the dissipative
rate changes, then the control law yields conservative results. Thus, it is necessary to design a control algorithm which provides a global solution for an optimized dissipative rate. Hence, a sum of square (SOS) approach is used to design a nonlinear H∞ control algorithm in order to obtain a global solution. Subsequently, an SOS based approach is used to design a nonlinear H∞ control algorithm for both steering and diving planes. Here, the HJI inequality is also con- verted into state-dependent LMIs in order to find out the solution for the nonlinear control problem. Firstly, the dynamics of diving and steering planes are transformed into an equivalent polynomial form, in which SOS decomposition technique can be easily employed. Using the SOS optimization technique, the control law is designed
for achieving the diving and steering motion of AUV by ensuring the L2 gain performance. This approach exhibits an extended stability region by transforming the quadratic Lyapunov function into a higher order Lyapunov function that results in improving the controller performance. All the developed nonlinear robust H∞ control algorithms are implemented firstly in MATLAB/Simulink and subsequently on the prototype AUV to verify their per- formances. Subsequently, the robustness analysis of all the control algorithms are performed in both diving and steering planes. From the results obtained and the as- sessment of the performances of all the developed nonlinear robust controllers, it is envisaged that the SOS based approach is desirable for real-time implementation in order to smoothly drive the AUV to achieve efficient tracking performance.
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Sethi, Aditya Kumar, and Vijay Ravichandran. "Pitch Control of Horizontal Axis Wind Turbine." Thesis, 2011. http://ethesis.nitrkl.ac.in/2430/1/Pitch_Control_of_Horizontal_Axis_Wind_Turbine.pdf.
Full textAbstract:
Wind energy is fast becoming the most preferable alternative to conventional sources of electric power. Owing to the perennial availability of wind and the considerable range of power control, wind turbines are now coming up in almost all parts of the world. In the early days of development, wind turbines were designed to rotate at constant speed through pitch control or stall control. The modern wind turbines implement pitch control in order to tap maximum energy at wind speeds lower than rated wind speed.
In this project, three different models of pitch actuator system have been studied and a discrete time adaptive PID model has been proposed where the gains of the PID controller are modified based on the time response parameters of the previous time cycle. It is expected to offer better control over a wide range of wind speeds.
Keywords: Pitch control, renewable energy, adaptive PID Control, Wind Energy Conversion Systems
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Dhanuka, Raghav. "Modelling of doubly fed induction generator based wind turbine." Thesis, 2013. http://ethesis.nitrkl.ac.in/5343/1/109EE0268.pdf.
Full textAbstract:
There has been a constant rise in the use of renewable energy resources. Global wind energy capacity soared by a fifth to 238GW at the end of 2011. India being the 5th largest player globally, accounted for 16GW. Wind energy is an important form of renewable energy as there is no greenhousE gas emission compared to non-renewable fossil fuels. There has been a rising demand for wind energy ever since its first implementation. This project work studies the power-speed characteristics and the torque-speed characteristics and the fundamentals of wind electrical systems along with the modeling of the various wind turbine features and simulation of the same using MATLAB-SIMULINK. It deals with the vector control and modeling of the Doubly-Fed Induction Generator, which can be used to transmit power to the network through both the stator and the converters connected to the rotor. The turbine current, voltage, power and other characteristics are studied on variation of the grid parameters.
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Deori, Anupam. "Grid Integration Issues of Distributed Generations." Thesis, 2015. http://ethesis.nitrkl.ac.in/7820/1/2015_Grid_Deori.pdf.
Full textAbstract:
Paucity in the energy scenario had made conservation of energy an essential issue. Usage of Renewable energy sources (RES) is increasing in the present era, which calls for green and clean energy sources. RES includes various forms viz., solar energy, wind energy, geothermal energy etc. but the most favored are the solar and wind energy. Most RES are intermittent in nature. To integrate RES to a utility grid is a quite challenging task, to track the maximum power point (MPP) of a consistently irradiated PV system is important and is yet another challenge. Of all the available methods in the MPPT context the Perturb and observe (P & O) method and incremental conductance method are the widely used techniques. In this project the P & O method is implemented for tracking the MPP. The tracking system conventionally is supplied the PV array voltage and current to track the MPP. In this thesis instead of having a sensor for measurement of the solar array current, it is estimated or observed with a sliding mode observer. The observer is based on sliding-mode and is constructed from the dynamic equations of the considered system viz. a single phase grid connected Photovoltaic system that has a Photovoltaic module and a single-phase H-bridge inverter. The solar array current is observed by the known values or measured values of the array voltage and inductor current. The current estimation is governed by the sliding mode observer gain, as we increase the value of the gain chattering problems come into being. The estimated value almost follows the original current and hence, is used to track the MPP. In this thesis at first the methodology of grid integration of distributed Photovoltaic systems are studied and simulated. And then an observer based on sliding-mode theory, the MPPT control was developed.
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Tarai, Rakesh Kumar. "Evaluation and Analysis of the Photovoltaic Potential for Odisha." Thesis, 2016. http://ethesis.nitrkl.ac.in/8297/1/2016-MT-214EE5495-Photovoltaic_Potential_for_Odisha.pdf.
Full textAbstract:
Solar energy is a potential resource for the various renewable energy options which is clean, inexhaustible and eco-friendly. The development of usage and installation of PV system needs a relevant solar policy making plan through proper assessment of solar PV Energy potential. The study uses the estimate of the PV potential of an area under consideration using the PVGIS online software. The study divides the total geographic area of into a grid of „mxn‟. The PVGIS evaluated the value of incident solar radiation and generated PV energy at central coordinate of each grid. The evaluation of energy potential for four cases (based on mounting and tracking) uses two critical parameters: annual incident Global radiation and annual PV Energy production. A methodology is presented to plot the rasterized maps of the solar energy potential. The study further discusses a case study of Odisha to show the usefulness of the proposed methodology to develop a district wise strategy for promoting the installation of grid-connected PV system. The decision to install a PV plant depends on three major factors: the climatic and environment conditions of the location, the viability of commercial operations, and the government policies. Considering uncertain nature of geographical parameters development of a reliable model to predict the energy output of a plant-to-be installed becomes essential. The study proposes models that consider only two meteorological variables collected from 1195 locations of Odisha: total annual incident global radiation on the PV module and annual average air temperature. The thesis focuses on simplification at every stage of the development while validating the preciseness of the model. A case study of NIT Rourkela is considered to apply a various methods for the evaluation of PV potential. Again the current solar policy framework of India is reviewed along with the challenges the nation has to face for achieving the targets.
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Nicolae, Dan Valentin. "Non-conventional methods for energy extraction from high voltage transmission lines." Thesis, 2004. http://hdl.handle.net/10352/143.
Full textAbstract:
Thesis (D. Tech. Electrical engineering) --Vaal University of TechnologyA comprehensive study upon "Non-conventional methods for energy extraction from the high voltage transmission lines" was addressed in this thesis. As defined in this study, a non-conventional method to extract energy is one that does not touch the conductors of the line. The theoretical framework which originated in the Maxwell's equations was presented as a base for discussion of all the methods and the conditions for the extraction to be possible. This study presents various methods such as capacitive and inductive to extract energy from high voltage alternating current transmission lines (HVAC). Although in theory, for high voltage direct current transmission lines (HVDC), the conditions for extraction are not matched, there remain some methods that could still attract interest. The centre point of this thesis is the new power application of the Rogowski coil. This method is analysed in full extent starting from theoretical modelling, computer simulations, design of the actual Rogowski coil and power electronics associated with it, and experimental results on a reduced scale model. In doing this, strong mathematical tools and computer software such as Matlab 6, Quick Field and MathCAD were used. At the end of this thesis, some conclusions are presented together with new ideas for further research in the field.
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Mohapatra, Gopa Ranjan. "Voltage and stability analysis of distribution networks with non-conventional energy sources." Thesis, 1997. https://vuir.vu.edu.au/17910/.
Full textAbstract:
The impact of renewable energy installations connected to the utility grid is an important
issue concerning the technical and economic viability of harnessing these emerging
energy sources. Distribution networks must be carefully controlled in order to
maintain an acceptable power supply quality. The major sources of non-conventional
energy are small scale generation and storage from mini hydro, photovoltaic, wind
power, fuel cells, battery, flywheel, pump storage and biomass.
The aim of this thesis is to analyse the variation in voltage of the distribution network
when renewable energy sources are interconnected to the distribution network, in
terms of it's stability. In particular this study analyses the impact of interconnection of
small synchronous generators to the utility power grid. Dynamic stability analysis is
mainly concerned with analysing the response of electrical power system to small perturbation
about a given operating point. These studies are particularly important due
to the growing interest in interconnecting small renewable energy sources to large and
complex power systems. Simulation studies were carried out in order to find out the
transient stability and voltage stability of the non-conventional energy sources under
different operating conditions. A 5-second simulation was conducted using explicit
numerical integration (Euler method) and an integration time step of 0.002 second.
Power System Toolbox was used for analysis.The multimachine power system models
used in this thesis are generated in MATLAB code. The load flow is performed on the
multimachine power system correponding to the loading condition to be investigated.
The machines are represented by the two-axis models, the exciters by IEEE Type-1
models and the loads are modelled as constant impedances. To save programming
time, it has become common to limit the machine and exciter representations to some
specified models. The network admittance matrix is reduced by retaining only the internal buses of the generators. The reduced network, machine and exciter data are then
combined to form a linearised state-space model representing the entire system.
The simulation studies are applied to a four machine ten bus system. It is clear from
the analysis that much care should be taken based on the stability point of view while
interconnecting the small renewable energy sources to the utility. The renewable
energy sources should be interconnected at a point which provides higher stability
margin.The renewable energy sources is a viable option if it is connected to the
distribution network with necessary methods of improving transient stability and
voltage stability.
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Singh, Ayush, Manaranjan Dalai, and Subendhu Nayak. "Photovoltaic Energy Harvesting Circuit For Power Devices." Thesis, 2015. http://ethesis.nitrkl.ac.in/6843/1/Photovoltaic_Singh_2015.pdf.
Full textAbstract:
As an ideal solution to the great energy crisis that exists, a Photo Voltaic (PV) energy system is becoming more popular by the day, especially since the economic consequences for such solution are improving every day. Replacing conventional sources would require such systems to be highly efficient and user friendly. Proper functioning and practical application of this system requires precise control over voltage and current to deliver energy without affecting the mobile device. A solar based mobile charger is one such system which is used to recharge modern day smartphones. In this project, we have designed and developed a prototype of a Photo-Voltaic energy harvesting mobile charger which comprises of a Buck converter which is used to synthesize and modulate the DC power harvested from the PV module to suit the specific load requirements of a mobile phone. The system also consists of a controller which uses LM 2575 to charge the battery optimally. Proposed system is first simulated in the MATLAB-Simulink and then practically implemented to verify the theoretical results. The buck converter’s open loop control is achieved through ICs.
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Sriharsha, Ramineni, Kumar M. V. Ashwin, and Saraogi Nikhil. "Design and implementation of synchronous buck converter based PV energy system for battery charging applications." Thesis, 2011. http://ethesis.nitrkl.ac.in/2640/1/Sriharsha_B.Tech_Thesis.pdf.
Full textAbstract:
The Photo Voltaic (PV) energy system is a very new concept in use, which is gaining popularity due to increasing importance to research on alternative sources of energy over depletion of the conventional fossil fuels world-wide. The systems are being developed to extract energy from the sun in the most efficient manner and suit them to the available loads without affecting their performance.
In this project, synchronous buck converter based PV energy system for portable applications; especially low power device applications such as charging mobile phone batteries are considered. Here, the converter topology used uses soft switching technique to reduce the switching losses which is found prominently in the conventional buck converter, thus efficiency of the system is improved and the heating of MOSFETs due to switching losses reduce and the MOSFETs have a longer life. The DC power extracted from the PV array is synthesized and modulated by the converter to suit the load requirements. Further, the comparative study between the proposed synchronous buck converter and the conventional buck converter is analysed in terms of efficiency improvement and switching loss reduction.
The proposed system is simulated in the MATLAB-Simulink environment and the practical implementation of the proposed converter is done to validate the theoretical results. Open-loop control of synchronous buck converter based PV energy system is realised through ICs and experimental results were observed.
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Soren, Sanjay Kumar. "Single Phase Grid Connected PV System." Thesis, 2015. http://ethesis.nitrkl.ac.in/7058/1/Single_Soren_2015.pdf.
Full textAbstract:
A single phase grid connected with a photovoltaic (PV) power system that will provide high voltage gain with state model analysis for the control of the system has been presented. First the photovoltaic system is designed and simulated using MATLAB SIMULINK software. The output voltage of a PV array is comparatively low thus high voltage gain is necessary for grid-connection and synchronization. The PV system has been provided with a boost converter which will boost the low voltage of the PV array to high dc-voltage. A steady state model is obtained and is verified with the help of simulation. A full bridge inverterwith bidirectional power flow is used as the second power processing stage, which stabilizes the dc voltage and the output current. Further, a maximum-power-point-tracking method is employed in the PV system to obtain a high performance.
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Ramesh, Tejavathu. "Investigations on Direct Torque and Flux Control of Speed Sensorless Induction Motor Drive." Thesis, 2016. http://ethesis.nitrkl.ac.in/8054/1/2016_TRamesh511EE102_Investigations.pdf.
Full textAbstract:
The Induction motors (IM) are used worldwide as the workhorse in most of the industrial applications due to their simplicity, high performance, robustness and capability of operating in hazardous as well as extreme environmental conditions. However, the speed control of IM is complex as compared to the DC motor due to the presence of coupling between torque and flux producing components. The speed of the IM can be controlled using scalar control and vector control techniques. The most commonly used technique for speed control of IM is scalar control method. In this method, only the magnitude and frequency of the stator voltage or current is regulated. This method is easy to implement, but suffers from the poor dynamic response. Therefore, the vector control or field oriented control (FOC) is used for IM drives to achieve improved dynamic performance. In this method, the IM is operated like a fully compensated and separately excited DC motor. However, it requires more coordinate transformations, current controllers and modulation schemes. In order to get quick dynamic performance, direct torque and flux controlled (DTFC) IM drive is used. The DTFC is achieved by direct and independent control of flux linkages and electromagnetic torque through the selection of optimal inverter switching which gives fast torque and flux response without the use of current controllers, more coordinate transformations and modulation schemes. Many industries have marked various forms of IM drives using DTFC since 1980.
The linear fixed-gain proportional-integral (PI) based speed controller is used in DTFC of an IM drive (IMD) under various operating modes. However, The PI controller (PIC) requires proper and accurate gain values to get high performance. The PIC gain values are tuned for a specific operating point and which may not be able to perform satisfactorily when the load torque and operating point changes. Therefore, the PIC is replaced by Type-1 fuzzy logic controller (T1FLC) to improve the dynamic performance over a wide speed range and also load torque disturbance rejections. The T1FLC is simple, easy to implement and effectively deals with the nonlinear control system without requiring complex mathematical equations using simple logical rules, which are decided by the expert. In order to further improve the controller performance, the T1FLC is replaced by Type-2 fuzzy logic controller (T2FLC). The T2FLC effectively handles the large footprint of uncertainties compared to the T1FLC due to the availability of three-dimensional control with type-reduction technique (i.e. Type-2 fuzzy sets and Type-2 reducer set) in the defuzzification process, whereas the T1FLC consists only a Type-1 fuzzy sets and single membership function. The training data for T1FLC and T2FLC is selected based on the PIC scheme.
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Satapathy, Agnivesh, Meghashree Das, and Abhilash Majhi Samanta. "A Comprehensive Study on Battery Management System and Dynamic Analysis of Lithium Polymer Battery." Thesis, 2016. http://ethesis.nitrkl.ac.in/8084/1/2016_B_Tech_Agnivesh%2C_Meghashree_A_Comprehensive.pdf.
Full textAbstract:
The battery management system (BMS) is the most vital components of an electric vehicle. The main objective of the BMS is to ensure safe and consistent battery operation. To ensure proper functioning of the battery, state measuring and conditioning, cell balancing and control of charge are features that have been realized in BMS. The performance of different types of batteries is different under different environmental and working conditions. These irregularities in the performance of a battery are the primary challenge to the implementing of these functions in the BMS. State estimation of a battery, i.e. state of charge (SOC) and state of health (SOH), is a crucial function for a BMS. Li-Polymer battery has high discharge rate per unit mass and hence are very suitable for applications in electric automotive industry. This project addresses the modelling of a typical Li-Polymer battery and its dynamic characteristics. These battery models emulate the characteristics of real life Li-Po batteries, and help predict their behavior under different external as well as internal conditions. A dynamic model of lithium-polymer battery is designed using MATLAB/Simulink® in order to study the output characteristics of a lithium polymer battery unit. Dynamic simulations are done, which includes the effects of charging/discharging and operating temperature on battery terminal voltage output. The simulation results when compared to relevant studies, validated the model developed in the project.
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Ogeti, Pedda Suresh. "Robust Active and Reactive Power Control Schemes for a Doubly Fed Induction Generator Based Wind Energy Conversion System." Thesis, 2016. http://ethesis.nitrkl.ac.in/8207/1/thesis_NOV_2016_-510EE809.pdf.
Full textAbstract:
In view of resolving rising environmental concern arising out of fossil fuel based power generation, more electricity has to be generated from renewable energy sources. Out of the several renewable energy options available today, wind energy is considered to be the most promising one due to its high energy conversion efficiency compared to one of its competitors, i.e. the solar photovoltaic system. Now-a-days, large wind farms are generating thousands of megawatts of power feeding to the grid. In literature, number of controllers such as conventional proportional integral (PI) control, linear parameter varying (LPV) control, gain scheduling control, robust control, model predictive control have been proposed for both torque and pitch control. In these controllers, some of the important issues such as robustness for nonlinear dynamics of wind turbine and stability are not considered simultaneously. Hence, it is necessary to design appropriate controllers for extracting maximum power from the wind turbine whilst the robustness and stability of the Wind Energy Conversion System (WECS) are ensured. Hence, in this thesis, firstly the focus is made to design control system for the wind turbine coupled with the DFIG (torque and pitch control) using one of the very promising robust control paradigm called sliding mode controller for achieving robustness, reducing chattering phenomenon and stability of the WECS. Since the number of terms in control inputs (i.e. torque and pitch angle) and outputs (i.e. DFIG output power and speed) are more in wind control dynamics, selection of significant terms is important for reducing the complexity of controlling. Therefore, a Nonlinear Autoregressive Moving Average with exogenous input (NARMAX) model of the WECS has been developed. The parameters of this NARMAX model are estimated by suitably designing an on-line adaptive Recursive Least squares (RLS) algorithm. Subsequently for controlling speed and achieving efficient power regulation of the WECS a nonlinear model predictive controller (NAMPC) has been developed in which the control variables (torque and pitch) are optimised by formulating a cost function. Subsequently for the WECS, the power converters connecting the DFIG to the grid have been designed. For controlling stator active and reactive power of DFIG connected to the grid, a state feedback controller for the DFIG has been developed using a linear quadratic optimal theory with preview concept. This Linear Quadratic Regulator Optimal Preview Control (LQROPC) scheme is employed with a stator voltage oriented control (SVOC) technique. This Optimal preview control is used to solve the tracking and rejection problems with an assumption that the signals to be tracked or rejected are available a priori by a certain amount of time. Even though the OPC provides very good tracking and disturbance suppression performance, but it is sensitive to the DFIG circuit parameters which makes the WECS system unstable. Hence, to address the parameter uncertainty of the DFIG, a sliding mode controller has been proposed and the robustness of the WECS have been verified by using the Lyapunov criterion. Then, a 2 kW DFIG based WECS experimental setup has been developed in the laboratory to study the effectiveness of the controllers developed.
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Behera, Anil Kumar. "Design, Analysis and Development of MPPT Controller for Stand-Alone PV System Using Buck Converter." Thesis, 2017. http://ethesis.nitrkl.ac.in/8910/1/2017_MT_AKBehera.pdf.
Full textAbstract:
When a PV cell/array is irradiated with solar rays, it converts the solar energy into electrical energy. But, its conversion efficiency is very low. The power and voltage characteristics are non-linear in nature. It shows that there is a point where the PV cell/array reaches its maximum power. This thesis presents a method called the Maximum Power Point Tracking (MPPT) to get the maximum power from the PV cell/array at all times. The power vs voltage and current vs voltage characteristics of the PV panel are experimentally obtained. From the characteristics obtained, we can find out the voltage and current of the PV Panel corresponding to maximum power point i.e. we get VMPP , MPP I and PMPP . The MPPT is performed in simulation by using MATLAB/SIMULINK. The MPPT technique used here is the Perturb and Observe (P&O) method, which is in the form of a recursive algorithm. The graphs of panel voltage ( VPV ), panel current ( PV I ) and load power ( POUT ) are checked. It is verified that the final values of these graphs are very close to the actual values of VMPP , MPP I and PMPP respectively of the panel. The hardware design for the buck converter is done assembling the required components. Open loop operation is performed on the designed buck converter at different switching frequencies. The output voltage and gate-pulse waveforms are observed on the oscilloscope.
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Narendra, Kinjarapu. "Load Frequency Control for a Distributed Grid System Involving Wind and Hydro Power Generation." Thesis, 2017. http://ethesis.nitrkl.ac.in/8925/1/2017_MT_KNarendra.pdf.
Full textAbstract:
The use of renewable energy resources in the power system has been increased in the recent years. But the power production by these resources can’t be controlled like in thermal plants. As a result, the standalone operation of renewable energy is not reliable. Hence, grid connection of these along with conventional plants is preferred due to improved performance in response to dynamic load. It is observed that fluctuations in frequency, caused due to load variations, are high with increase in penetration of renewable resources. In order to suppress frequency deviations owing to load and generating power fluctuations caused by penetration of renewable resources, there are many load frequency control (LFC) methods. They include Flat Frequency Control (FFC), Tie-line Bias Control (TBC), and Flat Tie-line Control (FTC). The frequency and tie-line flow are controlled by tie-line bias control (TBC). In this work, a PID control technique is adopted to control frequency and tie-line power bias in a power system network involving wind, hydro and thermal plants.
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Tripathy, Swastik. "State-Space Modeling of Fuel Cell Based Power Generation Systems for Stationary Load Applications." Thesis, 2016. http://ethesis.nitrkl.ac.in/9116/1/2016_MT_STripathy.pdf.
Full textAbstract:
The application of PEM fuel as power sources requires a state space modeling of the fuel cell system. The principles of working of a fuel cell system were studied at first. The different types of fuel cells and their applications are also looked into. The characteristics of the proton exchange membrane (PEM) fuel cells are studied along with the causes of voltage drop. This project investigates the fuel cell voltage characteristics and then attempts to develop a state space model for a stationary power generation purposes. Effort is made to implement the first three simple state variable equations using MATLAB Simulink under stepwise varying load current conditions. For modeling a particular fuel cell application the determination of values for the different state variables will lead to design of a suitable controller.
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Mukhopadhyay, Arpan. "Design of Two Stage Single Phase Standalone Photovoltaic System with Battery Storage." Thesis, 2016. http://ethesis.nitrkl.ac.in/9336/1/2016_MT_AMukhopadhyay.pdf.
Full textAbstract:
In this work, a photovoltaic system was designed that supplies a single phase standalone load at 230V, 50Hz. As PV is the only source of power and due to intermittency of solar radiation, a battery storage was added to ride through the periods of insufficient power generation by the solar arrays. Lead acid battery was chosen due to its low cost per capacity.
Also, the issue of maintaining power balance at all times is very much essential and this problem has been handled in this project in a diligent manner. For interfacing the battery to the photovoltaic system, a bidirectional DC-DC converter has been used. Maximum Power Point tracking is accomplished by a Boost converter, which also does the work of stepping up the voltage from the array into the range suitable for inverter. As the power produced by the PV array flows through the boost converter and inverter before reaching the load, it is called a two stage system. The energy balance has been accomplished without using communication infrastructure, that is all the power electronic interfaces are controlled by three independent loops. A means of knowing the exact average value of the pulsating DC bus voltage without approximations and complex computations has been demonstrated. This enables the control loops to eliminate the effect of pulsating DC bus voltage, caused by the single phase inverter, on the battery. This ensures that the battery current does not suffer from direction reversal at double the AC line frequency, especially when the PV power and load power are close enough, which is quite common in a PV system. This prevents rapid deterioration of battery lifetime.
Also, the system has been simulated in MATLAB/SIMULAINK and simulation results shows the working of Photovoltaic System.
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Dhanuk, Umesh. "Detailed Study, Modeling and Control of Grid Connected Photovoltaic System with Battery Storage." Thesis, 2018. http://ethesis.nitrkl.ac.in/9666/1/2018_MT_216EE5313_UDhanuk_Detailed.pdf.
Full textAbstract:
As we know unconventional resources are most,used to resources in all over the world. These resources include coal, natural oil, fossil fuels, etc. these all unconventional resources are in the verge of exhaust level.Therefore,to fulfill all the load demand,we have to think for the different alternative solution. Renewable resources or we can say that conventional resources are the incredible match for the same, it includes several conventional resources such as solar, wind, tidal, geothermal etc. in our setup, surplus energy generated by the panel can be store in BSS or either be sold back to utility grid to prevent from energy loss at the same time our load demand must be fulfill in all condition. In this setup, our first priority is to fulfill the requirement of the load demand, and if surplus energy is there then this whole surplus energy we have to use for BSS or to make money from the electricity board by providing the excess power to utility grid. On the other hand, our second task is, energy give to grid when there is having high price, similarly energy take from the grid when price related to energy is low, but in all condition our first priority is to keep the load demand full.For that we have to choose the BSS such that it can provide energy whenever there is requirement,doesn’t matter for making money or to provide uninterrupted power supply to load. At the same time also,we have to keep minimum cost associated with BSS.
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Shrivastava, Sonam. "Distributed Secondary Control Schemes for Islanded Microgrid." Thesis, 2019. http://ethesis.nitrkl.ac.in/10032/1/2019_PhD_SShrivastava_514EE1027_Distributed.pdf.
Full textAbstract:
Nowadays, electrical grids are made more intelligent, distributed and responsive. A microgrid is a small-scale modern power system that facilitates integration of Distributed Generators (DGs) such as photovoltaics, and wind turbine, local loads and energy storage units. Microgrids ensure the local power quality, safety and also prevent the grid from occurrence of unexpected harmful disturbances due to the intermittent nature of Renewable Energy Sources (RES). A microgrid can operate in both grid-tied mode and islanded mode in the event of preplanned scheduling or disturbances. In the grid-tied mode of operation, the voltage and frequency are governed by the main grid. In the islanded operating mode, control becomes more challenging due to the low equivalent inertia of RES, varying load demand, and uncertainty of DGs output. Microgrid control can be broadly categorized into hierarchical structure, in which the first level is primary droop control, which is locally implemented. It stabilizes the MG operating voltage and frequency after islanding. However, primary control leads to system voltage and frequency deviations from their nominal values. The second hierarchical level is the secondary control that compensates for the deviations caused by the primary control. Tertiary control is responsible the for global cost, and power flow optimization. It also regulates the power exchange from an external grid or with other microgrids.
This thesis primarily deals with a comprehensive distributed secondary control Strategies of an autonomous AC microgrid system modeled as a multi-agent system. The distributed structure avoids the necessity of a centralized control structure and complex bi-directional communication network, thereby improving reliability, scalability, and eliminate the risk of single-point-failure. The main secondary control objectives are microgrid voltage and frequency restoration and, accurate active and reactive power-sharing among the distributed generators. The asymptotic controllers limit the convergence performance and they are not suitable for fast-changing operating conditions. Therefore, a special emphasis is given to the finite-time convergence control approaches to achieve faster and flexible settling time for secondary control. The proposed control methodologies are fully distributed and each distributed generator communicate with their immediate neighbors for information sharing via a sparse communication network. The loss of communication link does not affect the controller performance much until the communication graph remains connected. Further, the proposed control schemes are scalable and support the important features such as scalability and plug and play operation of a microgrid system.
A dynamic average consensus-based distributed control scheme is proposed for voltage and frequency synchronization, that utilizes neighbor's DG information. The control law comprises of two terms, first term forces the agents to move towards following the reference value, whereas the second term causes the consensus among agents. The communication link delay analysis and upper bound on the allowable delay is derived in terms of the communication graph connectivity. From the obtained results, it is observed that this control scheme provides good tracking performance. However, the scheme does not guarantee finite-time restoration.
To deal with the sensitive loads and fast-changing operating conditions, and to obtain finite-time convergence, a distributed control scheme is then developed using the concept of cooperative control. A Lyapunov based stability and convergence analysis are presented which clearly shows that the convergence time is independent of microgrid system states and the microgrid line and load parameters. Flexible tuning of the convergence time is achieved by setting the controller parameters only. Also, for proportional power sharing, separate controllers have been designed in slower time-scale. From the results obtained, it is found that this controller has finite restoration time and also supports plug and play demand.
Another finite-time distributed control scheme is proposed which utilizes the information discovery scheme before the restoration operation, because of the unavailability of the global reference information with every distributed generator unit in a microgrid network. Further, this scheme provides finite-time frequency regulation and accurate reactive power-sharing along with the voltage restoration. The obtained results show that the proposed control scheme enables the plug and play operation and exhibits efficient performance under time-varying communication topology.
Further, a finite-time distributed control approach with constrained control input is proposed for voltage, frequency, and active power regulation. This control scheme also minimizes the control input transients and keep them well within their threshold limits.
To eliminate the effect of noise uncertainty and corrupted information reception, a noise-resilient control strategy is developed for voltage, frequency restoration. The proposed control scheme exhibit robust performance with changing communication topology, and changing noise parameters. It also outperforms than the existing noise resilient scheme in terms of restoration time and transients.
In order to demonstrate the effectiveness of the proposed control schemes, several simulation case studies of microgrid test system connected via a sparse communication
network are pursued in MATLAB/SimPowerSystem environment. The results are presented in the thesis together with the analysis.
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Mohanty, Subhashis, Ganta Suresh, and Rabisankar Jena. "ModellIng and Simulation of a Photovoltaic System with MPPT Controller." Thesis, 2015. http://ethesis.nitrkl.ac.in/7836/1/2015_BT_Modelling_Subhasis_Mohanty.pdf.
Full textAbstract:
Today with the growing demand for the Renewable energy, the demand for the PV power has been increased more due to its plenty of availability and easy controllability. The most important thing in the PV system designing is efficient conversion of solar energy into electrical energy and cost reduction. This work proposes modelling and simulation of a photovoltaic system. In this work the utilization of a three-diode model of a PV solar cell using voltage controlled resistors is highlighted. This model also calculates the series and shunt resistance by efficient iterative method and simulates the effects of various parameters such as temperature, irradiance. To reduce simulation time, the input parameters are limited to few. Based on the available information from the PV module datasheet the developed model allows the user to predict PV cell’s current-voltage and power-voltage characteristics curve by varying sunlight, cell temperature and series resistance value. To operate the panel at its maximum power point, Perturb and Observe algorithm is applied to generate the controlled gate pulse for the Boost converter. The characteristics curves obtained by the simulation of different models are matched with the data provided by manufacturers with respect to the changing values of above mentioned internal parameters.
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Acharya, Amlan. "Active and Reactive Power Control of a Grid Connected Photovoltaic Power System." Thesis, 2016. http://ethesis.nitrkl.ac.in/8156/1/2016_MT_214EE3421_Active_%26_Reactive.pdf.
Full textAbstract:
The world has been traditionally dependent on non-renewable sources of energy for industrial applications and other daily domestic applications. The modern world is moving fast towards greener sources. Various ongoing research works are dedicated towards meeting the demands of local loads with help of green energy. Solar energy is one of the most abundantly available forms of renewable energy. But extracting power from solar photovoltaic arrays according to the demand of the load under changing grid conditions and environmental conditions has been a challenge. In this work, active/reactive power control and maximum power point tracking control strategies are investigated. First a working model of solar array is developed and simulated using MATLAB/Simulink. This model is further used for our control strategies investigation purposes. The developed solar array is investigated under varying solar irradiation and varying temperatures. The effect of these factors on voltage, current and consequently on power is observed. A solar photovoltaic array of 100KW is used for simultaneous testing of active/reactive control and MPPT control. The active and reactive power control of photovoltaic array is implemented usually when the available solar power is sufficient, the active and reactive power is controlled in such a way that it follows the load‘s demand characteristics. The photovoltaic array acting as generator should be able to mitigate the sudden change in load demands successfully which is tested by simulating the load change conditions in MATLAB. This active/reactive power control is relatively simpler as it is a single stage configuration with an inverter. The inverter is responsible for controlling, processing and delivering the solar power to the load side efficiently. The MPPT control is investigated under changing solar irradiation from 800W/m2 to 1000W/m2 .The sudden injection in power due to increase in irradiation is seen. The solar photovoltaic array tracks the maximum power and delivers it to the load efficiently. The power at AC and DC sides of the inverter is verified. This two stage configuration is more complex in nature with three control loops. One loop is exclusively for MPPT control. The other two loops are for inverter power control and indirect control of solar photovoltaic voltage and inverter voltage. The ability to deliver maximum power under changing irradiation of the solar photovoltaic generator is simulated with help of MATLAB/Simulink.
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Awasthi, Rahul. "Active and Reactive Power Controller for Single Phase PV Grid Connected Inverter with LCL Filter." Thesis, 2016. http://ethesis.nitrkl.ac.in/8158/1/2016_MT_214EE4225_Active_%26_Reactive_Power.pdf.
Full textAbstract:
This thesis work is concentrated on Photovoltaic system connected with grid by an inverter to control Active Power and Reactive Power independently and reducing THD using LCL filter. Many exciting methods to control power are based on synchronous reference frame transformation, this method requires information on phase angle given by Phase-Locked loop (PLL). At first PV cell characteristics are drawn that help in making the proposed Photovoltaic system. PLL is avoided and a controller is designed for single phase grid connected inverter system connected with a LCL filter in stationary reference frame. To achieve necessary performance with independent control of active and reactive power injected in the grid the decoupling control strategies is adopted. As compared with orthodox control scheme of controlling power for single phase PV grid present scheme is highly reliable, fast in response and active and reactive power is controlled independently. Present control algorithm is easier and simpler as this scheme is implemented in stationary reference frame. To confine high resonant peak value active damping technique is used in the designed current controller. LCL filter designing has been done in such a way to reduce the net THD and total losses taking place in the inductor of the filter. Switching scheme of the inverter and LCL filter are used to obtain sinusoidal output phase voltage. Lastly, the proposed control scheme helps in controlling the THD and independent control of active and reactive power are achieved without PLL in the system. Dynamic performance of the system is analysed and various waveforms are studied using MATLAB/Simulink 2014a
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Mohanta, Prasanta Kumar. "Modeling and Control of a Grid Connected Photovoltaic System." Thesis, 2016. http://ethesis.nitrkl.ac.in/9251/1/2016_MT_PKMohanta.pdf.
Full textAbstract:
At present scenario, renewable energy sources have emerged as best alternative0source of energy for0future and to alleviate the environment pollution0problems. Renewable energy sources like solar energy, wind energy system etc. when connected to grid, termed as micro grid, uses0power electronics converters so as to interface between renewable energy system0and utility grid. Although solar energy conversion efficiency is very low, it has been preferred widely due to its abundant nature. An attempt has been taken to develop an improved MPPT which uses d-axis grid current and dc link voltage as reference. It not only tracks the maximum power effectively but also provides a dynamic response to the fast changing atmospheric condition. The converters used for interfacing, are basically a voltage source0inverter (VSI) connected to the source0network, operated in order to achieve0objectives such as to control the power0flow and also to have operate at unity0power factor. The grid is required to have independent0control of active & reactive power, proper grid0synchronization, improved power0quality and good transient response0during any fault conditions etc. The voltage0oriented control (VOC) implemented on the grid0side converter is universally adapted for independent control of the active and reactive power0of a grid as it is controlled in0synchronous rotating frame. However, the dynamic response0of grid, during abnormal condition, is very0sluggish and poor0power quality. In order to design a0controller for robust performance and0to know its control characteristics, 0VSI needs to be modeled accurately. This project0has taken an attempt to derive the small0signal analysis of a three phase0grid connected VSI and further, relevant0transfer functions have been0obtained from the model in order0to analyze the system performance, to0be used for designing a0controller by utilizing bode plots. The studied system is0then modeled and simulated in the0MATLAB-Simulink environment.
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Patnaik, K., and B. Samantaray. "A Study of Wind Energy Potential in India." Thesis, 2010. http://ethesis.nitrkl.ac.in/1732/1/thesis-d2.pdf.
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There is huge activity in wind power, pan-India with the installed capacity increasing to 10,000 MW. India today has the fifth largest installed capacity of wind power in the world with 11087MW installed capacity and potential for on-shore capabilities of 65000MW. However the plant load factor (PLF) in wind power generation is very low, often in the single digits. The increase in interest in wind energy is due to investment subsidies, tax holidays, and government action towards renewable energy playing a big part in nation’s energy system. There is a need to generate environment friendly power that not only raises energy efficiency and is sustainable too. The time has come for moving to generation based subsidies and understanding the drawbacks associated with wind power in India. The capital cost of wind power is third higher than conventional thermal power; further electrical problems like voltage flicker and variable frequency affect the implementation of wind farm. However advances in technologies such as offshore construction of wind turbines, advanced control methodologies, and simulation of wind energy affecting overall grid performance are making a case for wind energy.
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Vaghela, Dinesh L. "A study on non-conventional energy devices in rural areas of Surat district (Gujarat)." Thesis, 1993. http://hdl.handle.net/2009/5813.
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Das, Satyajit. "Robust Active and Reactive Power Controllers for a Grid Connected Wind Energy Conversion System." Thesis, 2019. http://ethesis.nitrkl.ac.in/10057/1/2019_PhD_DSatyajit_513EE1008_Robust.pdf.
Full textAbstract:
Permanent Magnet Synchronous Generator (PMSG) is widely used in a Wind energy Conversion System (WECS) due to its several advantages, such as gear less construction, high power density, less noise, high torque and ease of maintenance. The control objective for a PMSG based WECS is to regulate the active power extraction from the wind and at the same time to maintain the reactive power at zero value in order to achieve unity power factor operation of WECS. A number of control algorithms have been proposed in the past to control the active power and reactive power of WECS. However, a WECS is subjected to a large number of parametric uncertainties and external disturbances. Thus, it is necessary to negate the effect of parametric uncertainties and external disturbances appearing in the WECS dynamics in order to achieve satisfactory performance by designing suitable robust control algorithms.
A lot of research works have been directed to control the active power and reactive power of WECS. But parametric uncertainties greatly influence the active power and reactive power control performance in a WECS. Thus, challenges in designing suitable controllers for
regulating active power and reactive power of the WECS in face of parametric uncertainties and disturbances.
The thesis focuses on development of different robust control algorithms for a PMSG based grid connected WECS to control both reactive power in face of parametric uncertainties and disturbances. Since both the active power and reactive power of the PMSG are coupled with each other, hence it is necessary to design controllers such that the active power and reactive power can be controlled independently by appropriately decoupling the active power and reactive power control loops.
The thesis begins with development of a robust H∞ controller to regulate the active power and reactive power of PMSG based WECS delivered to the grid. The detailed design of the inner current control loop and the outer speed control loop are also presented. The H∞ based
robust controller for the PMSG is synthesized using MATLAB/Simulink. The performance of the proposed controller is first verified at nominal conditions of PMSG and then in the presence of the parametric uncertainties. To investigate the robustness of the proposed H∞ controller, stator resistance and stator inductance of the PMSG are varied and efficiency of the proposed H∞ controller in rejecting the effect of the external disturbance is also evaluated. The peak overshoot and the settling times of the active power response obtained by applying the proposed H∞
controller with the variation in these aforesaid parameters are compared. From the comparison, it is observed that the proposed controller is efficient in regulating the active power and reactive power of PMSG in face of parametric uncertainty and also able to reject the adverse effect of external disturbance in set point tracking.The efficiency of the proposed H∞ controller is also evaluated experimentally. Comparing the simulation and experimentation results it is concluded that the proposed H∞ controller effectively handles the parametric variation for setpoint tracking of active power and reactive power of WECS.
Although the proposed H∞ controller exhibits robust performance in regulating both the active power and reactive power but, the controller has some drawback i.e. the nominal performance of the WECS may slightly degrade. The design of this controller involves complex
mathematical calculations. Further, the designed H∞ controller is of high order and thus necessitates reduction of the order. Even though the proposed H∞ controller is able to reject the disturbance but the active power tracking performance is poor when disturbance is present. Moreover, the effect of the external disturbance needs to be attenuated faster than obtained with the proposed H∞ controller to minimize its adverse effect. In view of this,a Multi loop Active Disturbance Rejection Controller (MADRC) is designed to resolve the above limitations of the proposed H∞ controller. The basic idea behind designing the Active Disturbance Rejection Controller (ADRC) is to consider the internal dynamics, parametric uncertainties, the coupling term and the external disturbances as a lumped disturbance which can be estimated by designing an Extended State Observe (ESO). Subsequently, these lumped disturbances can be rejected by designing a suitable control law. The proposed MADRC is designed for speed control loop, d-axis current control loop and q-axis current control loop. The performance of the proposed MADRC is verified at nominal condition of PMSG from which it is observed that the peak overshoot and the settling time yielded by applying MADRC are less compared to the corresponding values obtained with the proposed H∞ controller. Also, the efficacy of the proposed controller is evaluated for variation of stator resistance and stator inductance of PMSG. For this, a step and variable wind speeds are applied to the WECS. From the obtained results it is observed that the MADRC regulates both the active power and reactive power under the aforesaid conditions effectively by generating suitable control actions. The performance of the proposed MADRC in active power and reactive power tracking in face of parametric uncertainties is also compared with the Single loop Active Disturbance rejection Controller (SADRC) by applying a step change in wind speed. On comparing the results, it is found that in the case of MADRC, the peak overshoot and settling time are less than that of SADRC in q-axis current and in active power responses of the PMSG. Further, the effectiveness of the proposed MADRC to reject the effect of the disturbance is verified by applying a step change in wind speed. From the result analysis, it is observed that the proposed MADRC is efficient to reject the external disturbance faster as compared to the H∞ controller. The adverse effect of the disturbance is less visible in terms of lower values peak overshoot yielded by MADRC as compared to the H∞ controller.
Although, the performance MADRC is satisfactory in active and reactive power tracking of WECS in the presence of parametric variation and external disturbances, there lie some drawbacks in this control scheme are as well. The exact estimation of the lumped disturbance by the ESO is difficult. Moreover, if the total disturbance is not constant, the estimation error in ESO may not converge to zero. Hence, to resolve this problem a Two Degree of Freedom Internal Model Controller based Active disturbance Rejection Controller (TDFIMC-ADRC) is designed. In TDFIMC-ADRC, the exact mathematical model of WECS is not required when designing a controller for WECS. In TDFIMC-ADRC, the ESO is omitted and a set point and a disturbance rejection filters are incorporated in this control scheme. Hence, the setpoint tracking and disturbance rejection are achieved in two individual decoupled control loop. The design of setpoint tracking and disturbance rejection filters for all the control loops (speed, d-axis current and q-axis current) is presented. With these filters, the proposed TDFIMC-ADRC is designed and then the performance of the proposed TDFIMC-ADRC is evaluated for active and reactive power tracking in a PMSG based WECS. The performance of the controller is verified at nominal condition of the PMSG and subsequently by varying Rs and Ls of PMSG. From the results analysis, it is observe that the proposed TDFIMC-ADRC exhibits superior performance i.e. yielded less peak overshoot and less settling time as compared to the corresponding values obtained with MADRC with a step change in wind speed and a variable change in wind speed. The efficacy of the proposed TDFIMC-ADRC controller to attenuate the adverse effect of the external disturbance is also studied. It is observed that the proposed TDFIMC-ADRC rejects the disturbance faster compared to the both H∞ controller and MADRC.
From the simulation and experimental results obtained when by applying all the above three proposed controllers, it is observed that these controllers exhibit robust performance for set point tracking of active power and reactive power of the PMSG based WECS. The performance indices such as peak overshoot and settling time in the active power and reactive
power responses obtained by applying the proposed three robust controllers are compared in the presence of the parametric uncertainty. From the comparative assessment, it is envisaged that the TDFIMC-ADRC exhibits superior performance amongst the three in face of parametric
uncertainties. The effect of the disturbance in the active power and reactive power tracking performance for all the proposed controller are compared. From this comparison, it is also observed that the TDFIMC-ADRC rejects the disturbance accurately and quickly compared
to both H∞ and MADRC. Moreover, the proposed TDFIMC-ADRC has simple structure and its implementation in both simulation and experiment becomes less complex as compared to both H∞ controller and MADRC for a PMSG based WECS in face of parametric uncertainties and external disturbances.Thus it is concluded for achieving robust active power and reactive power control performances when parametric uncertainties and external disturbances exist, the TDFIMC-ADRC is the best choice amongst all the proposed controllers described in the thesis.