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  • 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.
1

Amplificadores de tensão utilizados para injetar formas de ondas sintetizadas em lâmpadas HPS

Rodovalho, Diógenes Simão 28 July 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objectives of this work and present a class D amplifiers and full-bridge class D amplifier used to supply one or more high pressure sodium lamps (HPS). In this work, the lamps are feed a synthesized waveform to avoid acoustic resonance. The waveform injected contains a fundamental frequency around 1kHz and its third harmonic. The injection waveform synthesized prevents acoustic resonance the spread power the lamp in spectrum frequency. The ease of control of Class D amplifiers ensures a waveform without major changes in relation to entry. The control strategy and operation of the amplifiers stages have been shown. Studies were presented the strategies used to avoid acoustic resonance and detailed analysis of the injection waveform synthesized. The results of the simulations and practical results obtained were presented. / O objetivo deste trabalho é apresentar a utilização de amplificadores classe D e um nova topologia de amplificador full-bridge, classe D, para acionar uma ou mais lâmpadas de Alta Pressão de Sódio (HPS). As lâmpadas são alimentadas por uma forma de onda sintetizada para evitar a ressonância acústica, onde a forma de onda contém uma frequência fundamental de 1kHz e sua terceira harmônica. Essa técnica é utilizada para evitar o surgimento da ressonância acústica, espalhando no espectro da frequência a potência distribuída na lâmpada. A facilidade do controle dos amplificadores classe D garante uma forma de onda sem grandes variações em relação à entrada. A estratégia de controle e as etapas de funcionamento dos amplificadores são apresentadas juntamente ao estudo das técnicas utilizadas para evitar a ressonância acústica e a análise detalhada sobre a injeção da forma de onda sintetizada. Os resultados das simulações e os resultados práticos obtidos foram apresentados. / Doutor em Ciências
2

Modes d'Alimentation et de Commande des lampes sodium haute pression en vue d’éviter les résonances acoustiques / Supply and control methods for acoustic resonances avoidance in high intensity discharge lamp

Chhun, Labo 07 May 2010 (has links)
Grâce au développement de la technologie des semi-conducteurs, les ballasts électroniques fonctionnant en haute fréquence offrent des avantages considérables par rapport aux ballasts électromagnétiques conventionnels. Il en résulte une augmentation de la durée de vie de la lampe, une diminution du volume et du poids du système et surtout un meilleur contrôle de son fonctionnement afin de réduire notamment la consommation électrique. Parmi des lampes à décharge, la lampe sodium haute pression a une excellente efficacité lumineuse et une longue durée de vie. Pourtant, quand la lampe fonctionne en haut fréquence, des perturbations de type « résonance acoustique (RA) » peuvent entraîner l’instabilité de la décharge, son extinction ou pire, la destruction de la lampe. Cette thèse, intitulée « Modes d’Alimentation et de Commande des lampes sodium haute pression en vue d’éviter les résonances acoustiques », traite de plusieurs problèmes. Les caractéristiques de la décharge haute pression, le phénomène de RA, ses conditions d’excitation (notamment au travers d’un phénomène d’hystérésis original) et la variation des paramètres électriques due à la présence de résonances acoustiques dans la lampe, ont été étudiés. Les résultats sont issus de travaux de simulation et expérimentaux menés au sein du laboratoire LAPLACE. Grâce à ces acquis fondamentaux, plusieurs nouvelles méthodes d’alimentation par l’injection de signaux à fréquences proches ont été proposées dans nos travaux. Il s’agit d’éviter la résonance acoustique dans la lampe alimentée par un ballast de structure très réduite par rapport aux solutions classiques. Cette méthode est basée sur le choix judicieux des signaux injectés dans la lampe et leur répartition, (alimentation par deux, trois ou cinq signaux, répartition symétrique, asymétrique totale ou partielle). Le résultat est un meilleur étalement du spectre et donc une réduction de puissances harmoniques sélectionnées permettant de s’adapter, à terme aux conditions d’excitation des RA, mais aussi les limitations de ces méthodes compte tenu du facteur crête. Enfin, différents types de commande en boucle fermée sont proposés, ils permettent d’assurer la stabilité de la décharge et le contrôle des puissances imposées dans la lampe. Les études théoriques, en simulation et expérimentales qui ont été conduites nous ont permis d’aboutir à des résultats concluants. / For high pressure sodium (HPS) lamps, the progress of semi-conductor technology has provided considerable advantages in the design of high frequency operated electronic ballasts, compared to conventional electromagnetic ballasts. The advantages deal with lamp lifetime improvement, ballast volume and mass reduction, and particularly with a better control of lamp operation for optimized power consumption. Among discharge lamps, high pressure sodium (HPS) lamp has excellent efficacy and long lifetime. However, when it is operated at high frequency, discharge perturbation namely “acoustic resonances (AR)” can provoke some lamp arc instabilities, extinction or, even worst, lamp destruction. The present thesis, entitled “Supply and control methods for acoustic resonances avoidance in high intensity discharge lamps” deals with several matters.  High intensity discharge (HID) characteristics, AR phenomenon, its excitation conditions (including the original features of AR hysteresis) and lamp electrical parameters variation due to AR presence, will be studied. The obtained results were provided by simulations and experimentations carried out in LAPLACE laboratory. Thanks to the acquired results of previous studies, several novel lamp supply strategies via adjacent frequency signals injection were proposed. The main concepts here consist in the avoidance of AR presented in a lamp supplied by designed electronic ballast with reduced structure, compared to classical solutions. Otherwise, the presented methods are based on pertinent choices of injected signals applied to the lamp and their frequency distributions (two, three or five signals and symmetric, partial asymmetric or total asymmetric signals). The studies actually showed better spreading of signal spectrum and power harmonic amplitudes reduction adapted to AR excitation conditions, while taking into account crest factor limitation. Finally, different control laws (PI, Hysteresis, Self-oscillation, Resonant controllers) were also proposed in order to guarantee lamp discharge stabilization and power controls. The theoretical and experimental studies including simulations were conducted to reach concluding results of our works.
3

Utvärdering av byte till energieffektiv belysning i tryckeri / An evaluation of energy efficient lighting replacement in a printing house

Björklund, Lina January 2019 (has links)
Resultatet av en energikartläggning på tryckeriet VK - Media visade det sig att en stor del av energin gick till den gamla belysningen. Den gamla belysningen med högtrycksnatriumarmaturer och högtrycksnatriumljuskällor byttes då ut mot en ny energieffektiv belysning med två olika LED-armaturer i packsalen på tryckeriet. Det ska nu utföras en utvärdering av belysningsbytet. Utvärderingen av belysningsbytet kommer att baseras på sänkningen i energianvändning, skillnader i belysningsstyrkor och förändring av arbetsmiljön.   Det främsta syftet med belysningsbytet är att sänka energianvändningen och att förbättra arbetsmiljön. Simuleringar på belysningen med högtrycksnatriumljuskällor och LED-armaturer har gjorts i DIALux evo. I DIALux gjordes beräkningar på belysningsstyrkor och energianvändning. Momentana effektmätningar med en multimeter har genomförts på belysningen före och efter bytet. För att sedan beräkna den årliga energianvändningen utifrån de uppmätta effekterna. Belysningsstyrkorna mättes med en luxmeter på plats i packsalen för att sedan beräkna medelbelysningsstyrkan och jämnheten för belysningen för att se om de står sig mot riktvärdena och jämföra dem med värdena från DIALux. Livscykelkostnaden beräknades för belysningen med högtrycksnatriumljuskällor och för belysningen med LED-armaturer. För den nya belysningen beräknades även paybacktiden.   Resultatet av beräkningar på energianvändningen visar att den årliga energianvändningen kommer att sänkas med 70 procent i och med bytet till LED-armaturer. Vid ett belysningsbyte är målet att den årliga energianvändningen ska sänkas med 50 procent. Medelbelysningsstyrkan för den nya LED-belysningen på cirka 680 lx möter kravet för medelbelysningsstyrkan på 300 lx som gäller för packsalen enligt standarden SS-EN 12464-1:2011. Livscykelkostnaden för den gamla belysningen och den nya LED-belysningen beräknades till ungefär 990 000 kronor respektive 330 000 kronor. Den diskonterade paybacktiden för LED-belysningen beräknades till 1,7 år. Gällande arbetsmiljön så har LED-belysningen monterats på en för låg armaturhöjd och kommer att höjas upp för att uppnå en behagligare arbetsmiljö.   Att investera i en ny energieffektiv belysning innebär en stor sänkning av den årliga energianvändningen samtidigt som investeringen har en relativt kort återbetalningstid. Det finns många fördelar med att byta ut den gamla belysningen som en förbättrad arbetsmiljö och sänkta kostnader. Förhoppningsvis kommer fler industrier att byta ut sin gamla belysning till energieffektiv belysning då de står för en stor del av den totala elanvändningen som går till belysning i Sverige. / The result of an energy survey at the printing company VK – Media showed that the energy use of the old lighting was a large part of the total energy use. The old lighting with high-pressure sodium luminaires and high-pressure sodium light sources was then replaced with a new energy-efficient lighting with two different LED luminaires in the packaging room at the printing company. An evaluation of the replacement of the luminaires should now be carried out. The evaluation of the lighting change is based on the reduction of energy use, differences of illuminance and changes in the working environment.   The primary aim of the lighting replacement is to reduce the energy use and to improve the working environment. Simulations on the lighting with high-pressure sodium light sources and LED luminaires have been made in DIALux evo. In DIALux, calculations were made on illuminance and energy use. Momentary power measurements with a multimeter have been carried out on the lighting before and after the replacement. The measured power was then used to calculate the annual energy use for the luminaires. The illuminance were measured with a luxmeter in the packing room and the measured values was then used to calculate the average illuminance and the uniformity of the lighting, to see if they stand against the guideline values and compare them with the values from DIALux. The life cycle cost was calculated for the lighting with high pressure sodium light sources and for the lighting with LED luminaires. The payback time was also calculated for the new lighting with LED luminaires.   The result of the calculations on the energy use showed that the annual energy use will be reduced by 70 per cent with the LED luminaires and the aim with a lighting replacement is to reduce the annual energy use by 50 percent. The average illuminance of the new LED lighting is about 680 lx meets the requirement for the average illuminance of 300 lx that applies to the packing room according to the standard SS-EN 12464-1: 2011. The life cycle cost of the old lighting and the new LED lighting was estimated at approximately 990,000 SEK and 330,000 SEK, respectively. The discounted payback time for the LED lighting was estimated at 1.7 years. Regarding the working environment, the LED lighting has been mounted at a luminaire height that is too low and will be raised to achieve a more comfortable working environment.   Investing in a new energy-efficient lighting means a large reduction in annual energy use, while the investment has a relatively short repayment period. There are many advantages to replacing the old lighting such as an improved work environment and reduced costs for the company. Hopefully, more industries will replace their old lighting for energy-efficient lighting as they account for a large part of the total electricity use when it comes to lighting in Sweden.
4

Integração de conversores estáticos aplicados a sistemas de iluminação pública / An integration of static converters applied to public lighting systems

Marchesan, Tiago Bandeira 20 December 2007 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents a family of integrated electronic ballasts applied to the public lighting system. The electronic ballasts are designed to supply High-Pressure Sodium lamps according to the desired lamp operation characteristics. The viability of use High-Pressure Sodium lamps in the public lighting system of Santa Maria city is studied along this work. Another topic addressed, is the acoustic resonance phenomenon occurrence. It is explained based on a large number of works previously presented in the literature, in order to choose for a reliable method to supply the lamp. The incremental impedance of the High-Pressure Sodium lamp is defined in the frequency domain. This model is used to analyze the lamp and ballast interaction. The presented integrated electronic ballasts to supply High-Pressure sodium lamps take the advantage of low cost and simplicity providing a stable lamp operation. / Este trabalho apresenta uma proposta de integração de conversores estáticos para alimentação de lâmpadas de vapor de sódio de alta pressão (HPS), baseando-se, fundamentalmente, na viabilidade de aplicação deste tipo de lâmpadas a sistemas de iluminação pública. Ao longo do trabalho, é discutida a viabilidade de aplicação das lâmpadas HPS ao sistema de iluminação pública existente na cidade de Santa Maria- RS, evidenciando os parâmetros técnicos necessários ao projeto e desenvolvimento de reatores eletrônicos. A abordagem do fenômeno da ressonância acústica é feita de forma consistente, avaliando-se trabalhos previamente publicados, a fim de se chegar a um método confiável para se alimentar a lâmpada HPS sem a excitação deste fenômeno. Além disso, uma análise do modelo de pequenos sinais da lâmpada traz uma visão dos principais estágios a serem empregados no reator para garantir um funcionamento estável do sistema. A metodologia de integração proposta para alimentação de lâmpadas HPS, através de reatores eletrônicos, sem a excitação do fenômeno da ressonância acústica, busca a redução de custos e a simplicidade do sistema, sem deixar de considerar os procedimentos necessários a uma operação estável e confiável.
5

Sistematização do projeto de reatores eletrônicos para alimentação de lâmpadas de vapor de sódio em alta pressão para iluminação pública / Design of a commercial approach of electronic ballasts to supply high-pressure sodium lamps in public lighting

Costa, Rafael Eduardo da 27 February 2009 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / This thesis presents an electronic ballast prototype to supply high-pressure sodium lamps used in public lighting. The goal is to develop a commercial approach able to replace the still commonly used electromagnetic ballasts, performing improvements in the public lighting system. Along this thesis, the state of art in lighting area is presented, especially in public lighting. Following, a bibliographic review about electronic ballasts to supply highpressure sodium lamps is done. Special attention is given to the low frequency square waveform supplying method, which is used in this thesis. Also, the features desired in electronic ballasts so they can operate the lamp reliably and according to the standards are discussed. From this review, the proposed topology is defined and its design is presented. A discrete control method is developed to guarantee the safe operation of the ballast during all lamp stages. A microcontroller is used to perform the control routines. Finally, experimental results are obtained, validating the proposed work. / Este trabalho apresenta uma proposta de sistematização do projeto de um reator eletrônico para alimentação de lâmpadas de vapor de sódio em alta pressão, para aplicação em iluminação pública. Com isto, pretende-se criar um dispositivo que venha a substituir os reatores eletromagnéticos, ainda comumente utilizados nesta aplicação, de modo a proporcionar melhorias nos atuais sistemas de iluminação pública. Ao longo deste trabalho, é feita uma revisão do estado da arte na área de iluminação, dando ênfase à iluminação pública. Em seguida, é apresentada uma revisão bibliográfica acerca dos métodos de alimentação de lâmpadas de vapor de sódio a partir de reatores eletrônicos, destacando-se a alimentação deste tipo de lâmpada com forma de onda quadrada em baixa freqüência, método utilizado neste trabalho. Também são discutidas as características que um reator eletrônico deve possuir para enquadrar-se nas normas vigentes e alimentar a lâmpada de forma confiável. A partir desta revisão, a topologia proposta é definida e seu projeto é apresentado. Uma metodologia de controle discreto é desenvolvida de forma a garantir a operação adequada do reator durante todas as etapas de funcionamento da lâmpada. Um microcontrolador é utilizado para executar as rotinas de controle. Finalmente, resultados experimentais são obtidos, de forma a validar o trabalho proposto.
6

Påverkan på växter av LED i gatuarmaturer / Impact of street LED luminaires on urban plants

Wickström, Karin, Hurtig, Jenny January 2017 (has links)
Det blir allt vanligare att kommuner väljer att förnya och byta ut de befintliga gatuarmaturerna från högtrycksnatrium till LED (light emitting diode) då LED drar mindre energi och har en bättre färgåtergivning än högtrycksnatrium. Däremot skiljer spektralfördelningen mycket mellan LED-modulen och högtrycksnatrium vilket leder till att staden kommer se annorlunda ut på natten. Vad händer då med växterna som växer i närheten av dessa nya armaturer? Det forskas mycket om hur LED skulle kunna användas för att effektivisera odling, men det finns inte så mycket information om vad som kommer hända i staden när LED blir den dominerande ljuskällan. Därför har denna undersökning som syfte att se hur LED respektive högtrycksnatrium i gatuarmaturerna påverkar de växter som växer kring vägarna, och om något av alternativen påverkar växterna mer än den andra. Syftet är också att öka medvetenheten om hur strålningen från LED-armaturer påverkar vår miljö.Kattgräs (Hordeum vulgare L.), Rajgräs (Lolium multiflorum L.) och en blandning av vilda blommor odlades under en period på 20 dagar, under antingen högtrycksnatrium eller LED. Armaturerna var tända dygnet runt och mätningar av längden på ett skott per sort och rum gjordes varje dag. Vid slutavläsningen mättes också medellängden och medianen för 20 strån av respektive grässort per rum. För vildblomsblandningen gjordes en visuell utvärdering.Medelvärdet hos både rajgräset och kattgräset var kortare för odlingarna som exponerats för LED än de odlingar som exponerats för högtrycksnatrium. Kattgräset var 4% kortare, och rajgräset var 16% kortare. Vid den visuella utvärderingen ansågs vildblomsblandningen som vuxit under högtrycksnatrium vara högre och rangligare än växterna under LED. LED-odlingen uppfattades något grönare medan högtrycksnatriumodlingen uppfattades som något gulare och blekare.Undersökningen visade att växterna påverkades olika beroende på om de exponerades för högtrycksnatrium eller LED. Detta skulle kunna resultera i att kommuner som investerar i LED-armaturer inte bara kan spara pengar på energiförbrukning utan också på underhåll av stadsmiljön. Vidare bör det göras fler fältstudier om vad som händer med miljön när armaturerna byts ut från högtrycksnatrium till LED. Det bör även göras liknande studier men som pågår under en längre tid.
7

Energetick a provozn­ optimalizace syst©mu veejn©ho osvÄtlen­ / Energy Optimization and Operation of Public Lighting

Houdek, Michal January 2010 (has links)
An objektive of this university graduation work is an essay about any possibilities for energy savings with operation optimalization of public lightings. Understandings and introduction operation problems of public lighting is devote in first part of this work. Here we can chapters as Importance of public lightings or Gulations and norms in ralation to public lightings. The bigist and special attention is concentrated to description to public lightings systems and it is basic components. Another main part of this work is demonstration of used systems that are leading to energy savings for public lightings. These problems are detailed and explained in chapter Regulation of public lighting systems. This graduation work is describing individual types of regulation with the systems that are used with these regulatios in systems of public lightings. The assignment of last part of graduation work was to make sample calculation of energy demand and calculatin of yearly consumption on exemplary temporary system of public lightings. For this occasion was extra special auxiliary application sytem set up inside the Microsoft Excel program where all individual calculations were done.
8

Návrh veřejného osvětlení obce / Proposal of the village public lighting

Schittenhelm, Dominik January 2016 (has links)
The thesis is divided into several parts. The first part is theoretical and its main focus is the description of public lighting and the theory regarding lighting technology. The second part continues with the research of the current state in Bezděkov village. The thesis further describes the proposal for the village public lighting with the use of HPS and LED technology, where village models are made for both options to show the requested result. The last part of the work deals with cables dimensioning, the selection of the most effective regulations for lighting, and finally the economic assessment of both projects, while both the investment expenses and the public lighting service fees for the next 20 years are included.
9

Automatiserad gatubelysning baserad på omgivningens ljusstyrka : Hur ljussensorteknik kan minska energianvändningen för utomhusbelysning / Automated street lighting based on the ambient lighting of the surroundings : How light sensor technology could reduce the energy usage for outdoor lighting

McCarthy, Tom January 2021 (has links)
Målet med arbetet var att undersöka hur enskilda gatlyktor skulle kunna utrustas med ljussensorteknik för att implementera automatisk dimring med syftet att sänka energianvändningen. Rapporter visar att väg- och gatubelysningen i Sverige stod för 626 GWh år 2016 samt att en stor del av ljuspunkterna fortfarande består av energikrävande högtrycksnatrium. Uppgifter visar även att energisnåla LED-armaturer blir alltmer förekommande som alternativ till högtryckslampor. Målet var att utveckla en prototyp för LED där funktionen bygger på att lysdioderna ska vara släckta när omgivningens ljusstyrka är hög och dynamisk dimras upp när omgivningens ljusstyrka minskar. Arbetet resulterade i en prototyp som fungerar tillfredsställande och efter uppsatta mål. Varje ljussensor läser in ett analogt mätvärde som tolkas av en mikrokontroller som sedan skickar en pulsbreddsmodulerad signal för styrning av lysdiodens belysningsnivå. Generellt visade arbetet att omfattande fortsatta studier behöver göras innan prototypen skulle kunna implementeras i verkligheten. Prototypen behöver även testas och kalibreras i utomhusmiljö med dagsljus. / The goal of this thesis was to investigate how individual streetlights could be equipped with light sensor technology to apply an automatic dimmer function with the purpose of reducing energy usage. Studies show that road and streetlights in Sweden accounted for 626 GWh during the year 2016 and that a large portion of the lights still consists of energy demanding high pressure sodium lamps. Reports also show that energy efficient LED is becoming more and more common as an alternative to high pressure lamps. The goal was to develop a prototype for LED lighting with the function to control the LED’s to be off when the surrounding light levels are high and to dynamically increase the output power when the surroundings light level go down. Each light sensor reads an analog value which is interpreted by a micro controller that sends a pulse width modulated signal to control the LED power output. The finished prototype worked satisfactory and according to the set goals of the thesis. Generally, the thesis showed that extensive research is needed before the prototype could be implemented in real life. The prototype also needs to be tested and calibrated in an outdoor environment with day light.

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