• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 30
  • 9
  • 7
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 51
  • 51
  • 29
  • 17
  • 13
  • 13
  • 12
  • 12
  • 11
  • 9
  • 8
  • 8
  • 8
  • 8
  • 8
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Návrh fotovoltaické elektrárny pro rodinný dům v okrese Jihlava / Design of a photovoltaic power plant for a family house near Jihlava

Dvořák, Vít January 2021 (has links)
This diploma thesis deals with the design of a photovoltaic solar power station for a specific family house in the Jihlava region. The aim of the work was to get acquainted with technologies about the production of solar systems, evaluate the market in the Czech Republic and create a design of photovoltaic solar power station. Three designs of power stations were created with the help of the PV * SOL design system. Each design uses different photovoltaic cell technology. The result of each power station design is a complete finished project, which is based on many factors such as the efficiency of the entire system in a certain location, financial analysis, return on investment and more. In addition, these projects meet the conditions for the preparation of the subsidy program Nová zelená úsporám. At the end of the work, all three designed power stations are evaluated and with the help of multicriteria analysis, the best and most advantageous power station design for the given locality is determined. In the end, the idea of further development of the project is presented.
22

Design of a Real-Time Model of a Photovoltaic Panel / Konstruktion av en realtidsmodell av en fotovoltaisk panel

Fjällid, Markus January 2015 (has links)
Photovoltaic panels are widely used to harvest solar energy. In the general application the panels are connected to an inverter that allows the power to be feed to the grid. The possibility to emulate a photovoltaic panel in a laboratory environment simplifies the development of inverters. Existing solutions are either expensive or not performing good enough. This thesis presents a real-time model that has fast enough transient response to be used with the future’s solar panel inverters. The solution is based on an interleaved synchronous buck converter with an analogue current control loop. A micro-controller is utilizing a look up table to steer the power stage to mimic the output of a real panel. The content of the look up table can be exchanged to emulate an arbitrary photovoltaic panel in different environmental conditions. The emulator output is stable in the load case with a typical inverter connected to it. It is oscillating with a limited amplitude under open circuit. A hardware implementation of the system confirms the functionality. The current controller can correct a load step in 20 μs. The output switching ripple is below 1 mA. / Fotovoltaiska paneler är ett väl etablerat sätt att ta tillvara på solenergi. Den vanligaste tillämpningen är att panelerna är anslutna till en växelriktare för att möjliggöra att energin matas ut på elnätet. Att kunna emulera en solcellspanel i laboratoriemiljö förenklar utvecklingen av växelriktare. Befintliga system är antingen dyra eller presterar inte bra nog. Denna avhandling presenterar en realtidsmodell som kan hantera transienta förlopp tillräckligt snabbt för att kunna användas med framtidens solpanelsväxelriktare. Lösningen är baserad på en tvåfas synkron buck-omvandlare med en analog strömreglering. En mikroprocessor använder uppslagstabell för att styra effektsteget till att efterlikna utsignalen från en verklig panel. Innehållet i uppslagstabellen kan bytas ut för att emulera en godtycklig solpanel i olika driftsförhållanden. Emulatorns utsignal är stabil med en typisk växelriktare ansluten som last. Utsignalen svänger med en begränsad amplitud under öppen krets. Experimentiella tester bekräftar funktionen. Strömregleringen kan korrigera ett belastningssteg inom 20 μs. Utgångens strömrippel är under 1 mA.
23

Administratívna budova s obchodnými priestormi Žilina / Office building with retail space Žilina

Hubocká, Zuzana January 2022 (has links)
Master project is dedicated to design nearly zero-energy office building with retail spaces in Žilina. The first part deals with architectural – building design. Building is designed for the plot nr. 7011 with flat surface and there is no other building. The building has three above-ground floors and one underground floor. Retail spaces are on the ground floor. The building is constructed on foundation strips and pads. The building is made of combined load-bearing structural system of reinforced concrete columns and external walls. External load-bearing structures of above ground floors are designed from reinforced concrete and Ytong system supplemented by ETICS made of mineral wool. Underground walls are made from watertight concrete. Floor slab structures are made from reinforced concrete. The building is covered with green warm flat roof. The second part deals with building interior installation. The primary source of heat, coldness and hot water is the heat pump. Ventilation in the building is provided by heating, ventilating and air conditioning (HVAC) units. The third part of the thesis includes the design and assessment of the photovoltaic power plant in terms of economics and ecology. The project was carried out in the AutoCad system. All structures comply with the valid standards and regulations.
24

Sintonia online de controladores PID adaptativo-ótimo via redes neuronais artificiais / Online tuning of adaptive-optimal PID controllers via artificial neural networks

Santos, Hilton Seheris da Silva 27 June 2017 (has links)
Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-07-18T19:13:43Z No. of bitstreams: 1 HiltonSantos.pdf: 3137200 bytes, checksum: a7b77b12eeb29959ab49e7ef675229d9 (MD5) / Made available in DSpace on 2017-07-18T19:13:43Z (GMT). No. of bitstreams: 1 HiltonSantos.pdf: 3137200 bytes, checksum: a7b77b12eeb29959ab49e7ef675229d9 (MD5) Previous issue date: 2017-06-27 / The emergence of new industrial plants with great complexity and the need to improve the operation of existing plants has fostered the development of high performance control systems, these systems must not only meet the design specifications, such as merit figures, but also operate at minimal cost and impacts at environment. Motivated by this demand, it is presented in this dissertation the development of methods for on-line tuning of control system parameters, ie, a methodology is presented for the on-line tuning of adaptive and optimal PID controllers via Artificial Neural Networks(ANNs). The approach developed in this dissertation is based on three PID controllers parameters. [Artificial neural networks with radial base functions and Model Predictive Control (MPC). From the union of these approaches a general formulation of an Adaptive-optimal PID controller via artificial neural networks with on-line tuning was presented. The on-line tuning methodology for the ANN parameters is presented in the context of MPC, predicting plant output. For the PID controller, we proposed a modification of the standard structure in order to adapt the error function. The adjustment of the PID controller parameters and the prediction of the optimally plant output, are performed by the ANN-RBF weights adjustments. In addition, an indoor implementation of the control system were proposed for the positioning of a photovoltaic panel. The performance evaluations of the proposed system were obtained from computational experiments results that were based on mathematical models and hardware experiments, that were obtained from a reduced model of a photovoltaic panel. Finally, a comparison between the proposed methodology with the classical PID controller were performed and the proposed methodology presented to be more flexible to the insertion of new performance metrics and the results achieved from the ANN, were better than the ones obtained by the classical PID tuning, such as: Ziegler-Nichols or trial and error. / O surgimento de novas plantas industriais com grande complexidade e a necessidade de melhorar a operação das plantas já existentes tem fomentado o desenvolvimento de sistemas de controle de alto desempenho, estes sistemas devem atender não só as especificações de projeto, tal como: figuras de mérito, mas também devem operar com um custo mínimo e sem causar impactos desastrosos para o meio ambiente. Motivados por esta demanda, apresenta-se nesta dissertação o desenvolvimento de métodos para sintonia online dos parâmetros dos sistemas de controle, ie, apresenta-se uma metodologia para a sintonia online de controladores PID adaptativo e ótimo via Redes Neurais Artificiais (RNAs). A abordagem desenvolvida nesta dissertação tem base as ações dos controladores PID de três termos, redes neurais artificiais com funções de base radial e Controle preditivo baseado em modelo (MPC - Model Predictive Control), a partir da união destas abordagens elabora-se a formulação geral do controlador PID Adaptativo-Ótimo via redes neurais artificiais, com sintonia online. A metodologia de ajuste online dos parâmetros da RNA está no contexto do MPC para predição de saída da planta. Para o caso do controlador PID, tem-se a modificação da estrutura padrão com o objetivo de adaptação em função do erro. O ajuste dos termos do controlador PID e da predição da saída na planta, de forma ótima, é realizada pelo ajustes dos pesos da RNA-RBF. Além disso, apresenta-se a implementação indoor do sistema de controle desenvolvido para o posicionamento de um painel fotovoltaico. As avaliações de desempenho do sistema proposto são obtidos de resultados de experimentos computacionais que são baseados em modelos matemáticos e experimentos em hardware que são obtidos de um modelo reduzido de um painel fotovoltaico. Por fim, comparando o PID clássico com o controlador desenvolvido constatou-se que este último apresenta mais flexibilidade para inserir novas métricas de desempenho e os resultados atingidos são melhores do que os parâmetros obtidos por meio da sintonia do PID clássica, tais como: métodos de Ziegler-Nichols ou tentativa e erro
25

Desempenho de um painel fotovoltaico de baixa tens?o, acoplado ao prot?tipo de um conversor dc/dc topologia Booster

Alc?ntara, Sara Maria Freitas de 18 June 2010 (has links)
Made available in DSpace on 2014-12-17T14:58:04Z (GMT). No. of bitstreams: 1 SaraMFA.pdf: 4966448 bytes, checksum: 1ef74fa9275b2d2eb81d82fd6bcd301f (MD5) Previous issue date: 2010-06-18 / Low voltage solar panels increase the reliability of solar panels due to reduction of in series associations the configurations of photovoltaic cells. The low voltage generation requires DCDC converters devices with high efficiency, enabling raise and regulate the output voltage. This study analyzes the performance of a photovoltaic panel of Solarex, MSX model 77, configured to generate an open circuit voltage of 10.5 V, with load voltage of 8.5 V, with short circuit current of 9 A and a power of 77 W. The solar panel was assembled in the isolated photovoltaic system configuration, with and without energy storage as an interface with a DCDC converter, Booster topology. The converter was designed and fabricated using SMD (Surface Mounted Devices) technology IC (integrated circuit) that regulates its output voltage at 14.2 V, with an efficiency of 87% and providing the load a maximum power of 20.88 W. The system was installed and instrumented for measurement and acquisition of the following data: luminosities, average global radiation (data of INPE Instituto Nacional de Pesquisas Espaciais), solar panel and environment temperatures, solar panel and DC-DC converter output voltages, panel, inverter, and battery charge output currents. The photovoltaic system was initially tested in the laboratory (simulating its functioning in ideal conditions of operation) and then subjected to testing in real field conditions. The panel inclination angle was set at 5.5?, consistent with the latitude of Natal city. Factors such as climatic conditions (simultaneous variations of temperature, solar luminosities and ra diation on the panel), values of load resistance, lower limit of the maximum power required by the load (20.88 W) were predominant factors that panel does not operate with energy efficiency levels greater than 5 to 6%. The average converter efficiency designed in the field test reached 95% / Pain?is solares de baixa tens?o aumentam a confiabilidade dos pain?is solares, devido ? redu??o das associa??es em s?rie nas configura??es das c?lulas fotovoltaicas. A gera??o em baixa tens?o requer dispositivos conversores DC/DC de alto rendimento, que possibilitem elevar e regular a tens?o de sa?da. O presente estudo analisa o desempenho de um painel fotovoltaico da Solarex, modelo MSX 77, configurado para gerar uma tens?o em aberto de 10,5 V, tens?o com carga de 8,5 V, com uma corrente de curto-circuito de 9,0 A, e uma pot?ncia de 77 Watts. O painel solar foi montado na configura??o de sistema fotovoltaico isolado, com e sem armazenamento de energia tendo como elemento de interface um conversor DC-DC, topologia Booster. O conversor foi projetado e confeccionado com circuitos integrados de tecnologia Surface Mounted Devices (SMD), para regular tens?o de sa?da em 14,2V, com rendimento de 87 % , disponibilizando a carga uma pot?ncia m?xima de 20,88W. O sistema foi instalado e instrumentado para medi??o e aquisi??o dos seguintes dados: luminosidades, radia??es m?dias globais (dados do Instituto Nacional de Pesquisas Espaciais (INPE)), temperaturas do painel solar, temperatura ambiente, tens?es de sa?da do painel solar, tens?o de sa?da do conversor DC-DC, correntes de sa?da do painel, do conversor, da carga e da bateria. O conjunto fotovoltaico foi inicialmente ensaiado em laborat?rio (simulando seu funcionamento em condi??es ideais de opera??o) e, em seguida, submetido a testes em condi??es reais de campo. O ?ngulo da inclina??o do painel foi fixado em 5,5?, compat?vel com a latitude da cidade de Natal. Fatores como condi??es clim?ticas (varia??es simult?neas de altas temperaturas e radia??es solares), valores da resist?ncia de carga, baixo limite da m?xima pot?ncia solicitada pela carga (20,88W) foram fatores predominantes para que painel n?o operasse com n?veis de efici?ncia energ?tica maiores que 5 ? 6 %. O rendimento m?dio do conversor projetado nos ensaios de campo alcan?ou 95 %
26

Measurement techniques and results aiding the design of photovoltaic energy harvesting systems

Schuss, C. (Christian) 20 June 2017 (has links)
Abstract This thesis presents measuring techniques as well as measured and simulated results with the aim of helping the design of photovoltaic energy harvesting systems. Therefore, cost-effective measurement setups were developed for collecting the amount of irradiation, for both stationary and moving photovoltaic (PV) installations. The impact of the time resolution of solar radiation data on estimating the available solar energy was investigated. For moving PV installations, the dynamics and the rate of changes in the available irradiation were studied in order to analyse the effects on maximum power point tracking (MPPT) algorithms. In addition, possibilities for harvesting PV energy in indoor environments were also investigated. The main contribution of this thesis is the effective testing of PV cells and complete PV panels: instead of measuring the characteristic I-V (Current-Voltage) response under strictly controlled artificial illumination, photovoltaics are simply biased externally. Then, with the help of synchronized thermography (ST), infrared (IR) images of the PV panel self-heating are recorded. In the obtained IR-images, defected areas are seen as cold spots, since they are not biased by the external power supply. From the calculated temperature variations, the size of the defect area can be calculated and, thus, the loss in output power can be estimated. The method is shown to work both with and without glass encapsulation. / Tiivistelmä Tämä työ esittelee mittaustekniikoita ja mitattuja ja simuloituja tuloksia aurinkoenergian keruujärjestelmien suunnittelun avuksi. Työtä varten kehitettiin kustannustehokas mittausjärjestelmä, jonka avulla arvioitiin aurinkoenergian määrää sekä stationaarisen että liikkuvan valokennon tapauksissa. Näiden lisäksi tutkittiin mittaustaajuuden vaikutusta arvioitaessa saatavilla olevan aurinkoenergian määrää. Liikkuvan PV (photovoltaic)-asennuksen avulla tutkittiin saatavilla olevan aurinkoenergian vaihtelun suuruutta ja nopeutta tarkoituksena analysoida näiden vaikutuksia käytettäviin MPPT-algoritmeihin. Tämä lisäksi tutkittiin myös valoenergian keruumahdollisuuksia sisätiloissa. Työn tärkein kontribuutio on valokennojen ja kokonaisten valopaneelien toiminnallisuuden testaamisen tehostaminen. Tyypillisesti PV:n toiminnallisuus varmistetaan tarkasti määritetyssä ympäristössä suoritetun I-V -ominaiskäyrämittauksen avulla. Tämän työn menetelmä on yksinkertaisesti biasoida PV:t ulkoisesti, minkä jälkeen ST (synchronized thermpgraphy) -kuvauksen avulla määritetään PV-paneelien itselämpenemistä kuvaavat infrapunakuvat. Paneelin vioittuneet alueet erottuvat IR-kuvissa kylminä alueina ulkoisen biasoinnin puuttuessa. IR-kuvista havaituista lämpötilavaihteluista on mahdollista määrittää vioittuneen alueen koko ja siten arvioida myös menetettyä lähtötehoa. Kyseisen metodin toimivuus osoitettiin niin lasikoteloiduilla kuin ilman sitä olevilla PV-paneeleilla.
27

Energetické zásobování veletržního areálu / Energy supplies fairgrounds

Foit, Vladimír January 2017 (has links)
The diploma thesis titled Energy supplies fairgrounds is divided into four parts. The first part is devoted to the theory of sources of froze and heat energy. The next part deals with current condition of energy supplies of fairgrounds. The third part is based on the design of possible adjustment of energetic management for both the whole compound and partial objects. The last part sums up all the adjustments and evaluates all the real variants by closer economic analysis.
28

Regulátor pro nabíjení olověných akumulátorů z fotovoltaického panelu / Charge controller for solar panel based charging of lead-acid batteries

Korenčiak, Peter January 2011 (has links)
Tato diplomová práce se zabývá návrhem a realizací regulátoru pro použití v solárním systému s větším počtem olověných akumulátorů. Takový regulátor umožňuje nezávislé připojení a řízení nabíjení většího počtu akumulátorů různého stáří a parametrů. To je v kontrastu s řešeními obsahujícími jedno připojení pro více baterií připojených paralelně, kde se míchání baterií různého druhu a stáří nedoporučuje. Tento regulátor nabízí vysokou škálovatelnost skladování energie v solárním systému. Umožňuje také používat starší baterie s novými, místo nutnosti staré baterie nahradit, když jejich kapacita klesne pod požadovanou úroveň. V této práci jsou podrobně popsány požadavky, návrh hardwaru a softwaru a implementace regulátoru s nominálním výstupním proudem 20A pro pět 12V olověných baterií. Práce popisuje také další funkce, stejně jako alternativní návrhy a algoritmy. Důležitá část práce se zabývá designem spínačů pro velké proudy, ochrany proti zkratu a obvodů pro měření stejnosměrného proudu. Správná funkčnost regulátoru byla ověřena měřením.
29

Dlouhodobé sledování parametrů fotovoltaických panelů / Long-term monitoring of parameters of photovoltaic modules

Kladiva, Roman January 2013 (has links)
This thesis deals with the influence of degradation mechanisms to change the parameters of photovoltaic panels. The aim of the study was the long-term monitoring of selected solar modules, comparing their parameters with measurements from previous years and the evaluation of degradation mechanisms on their properties. The theoretical part is focused on the description of the monitored parameters and defects Panel, are discussed measuring methods by which the modules were monitored. Experimental part then consists of measuring modules individual test methods. The measured values were subsequently constructed graphical dependence, and the results were compared with measurements from previous years. The last part of the thesis is devoted to evaluation of the degradation of PV modules.
30

Návrh skladby zdrojů pro síťovou nezávislost / Draft mix for network independence

Horváth, Radovan January 2016 (has links)
The aim of this diploma thesis is the development of research on the topic of the draft mix for network independence. Next is the outline the various design solutions of the battery systems for accumulation electric energy and balance model energy supply system for the selected object. The practical part of diploma thesis deals with necessary resources and the size of batteries for autonomous operation during the summer months and also implements technical and economic studies aimed at finding cost-effective solutions. The work is divided into 6 chapters that contain 16 tables and 18 figures. Diploma thesis brings an option to configure a photovoltaic system and also describes the features, functions and the choice between the most used technologies. Evaluation of results of theoretical methods are described in the final part.

Page generated in 0.0427 seconds