• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 381
  • 48
  • 29
  • 23
  • 16
  • 9
  • 9
  • 8
  • 6
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • Tagged with
  • 640
  • 640
  • 185
  • 162
  • 147
  • 102
  • 70
  • 68
  • 67
  • 65
  • 63
  • 60
  • 59
  • 59
  • 53
  • 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.
361

Assessing the sustainability of transportation fuels : the air quality impacts of petroleum, bio and electrically powered vehicles

Alhajeri, Nawaf Salem 22 October 2010 (has links)
Transportation fleet emissions have a dominant role in air quality because of their significant contribution to ozone precursor and greenhouse gas emissions. Regulatory policies have emphasized improvements in vehicle fuel economy, alternative fuel use, and engine and vehicle technologies as approaches for obtaining transportation systems that support sustainable development. This study examined the air quality impacts of the partial electrification of the transportation fleet and the use of biofuels for the Austin Metropolitan Statistical Area under a 2030 vision of regional population growth and urban development using the Comprehensive Air Quality Model with extensions (CAMx). Different strategies were considered including the use of Plug-in Hybrid Electric Vehicles (PHEVs) with nighttime charging using excess capacity from electricity generation units and the replacement of conventional petroleum fuels with different percentages of the biofuels E85 and B100 along or in combination. Comparisons between a 2030 regional vision of growth assuming a continuation of current development trends (denoted as Envision Central Texas A or ECT A) in the Austin MSA and the electrification and biofuels scenarios were evaluated using different metrics, including changes in daily maximum 1-hour and 8-hour ozone concentrations, total area, time integrated area and total daily population exposure exceeding different 1-hour ozone concentration thresholds. Changes in ozone precursor emissions and predicted carbon monoxide and aldehyde concentrations were also determined for each scenario. Maximum changes in hourly ozone concentration from the use of PHEVs ranged from -8.5 to 2.2 ppb relative to ECT A. Replacement of petroleum based fuels with E85 had a lesser effect than PHEVs on maximum daily ozone concentrations. The maximum reduction due to replacement of 100% of gasoline fuel in light and heavy duty gasoline vehicles by E85 ranged from -2.1 to 2.8 ppb. The magnitude of the effect was sensitive to the biofuel penetration level. Unlike E85, B100 negatively impacted hourly ozone concentrations relative to the 2030 ECT A case. As the replacement level of petroleum-diesel fuel with B100 in diesel vehicles increased, hourly ozone concentrations increased as well. However, changes due to the penetration of B100 were relatively smaller than those due to E85 since the gasoline fraction of the fleet is larger than the diesel fraction. Because of the reductions in NOx emissions associated with E85, the results for the biofuels combination scenario were similar to those for the E85 scenario. Also, the results showed that as the threshold ozone concentration increased, so too did the percentage reductions in total daily population exposure for the PHEV, E85, and biofuel combination scenarios relative to ECT A. The greatest reductions in population exposure under higher threshold ozone concentrations were achieved with the E85 100% and 17% PHEV with EGU controls scenarios, while the B100 scenarios resulted in greater population exposure under higher threshold ozone concentrations. / text
362

Benefits of Coordinating Plug-In Electric Vehicles in Electric Power Systems : Through Market Prices and Use-of-System Network Charges

Momber, Ilan January 2015 (has links)
Both electric power systems and the transportation sector are essential constituents to modern life, enhancing social welfare, enabling economic prosperity and ultimately providing well-being to the people. However, to mitigate adverse climatological effects of emitting greenhouse gases, a rigorous de-carbonization of both industries has been set on the political agenda in many parts of the world. To this end, electrifying personal vehicles is believed to contribute to an affordable and reliable energy model that provides tolerable environmental impact. Representing an inherently flexible electricity demand, plug-in electric vehicles (PEVs) promise to facilitate the integration of variable renewable energy sources. Yet, how should the PEVs' system usage be ideally coordinated for providing benefits to electric power systems in the presence of resource scarcity? The thesis develops a model of an aggregation agent as the interface to the wholesale electricity generators, which is envisaged to be in charge of procuring energy in electricity markets, exposed to uncertainty in prices, fleet availability and demand requirements. This aggregator could coordinate the PEV charging either with direct load control (DLC), i.e., sending power set points to the individual vehicles, or with indirect load control (ILC), i.e., by sending retail price signals. Contributing to the technical literature this thesis has on the one hand proposed a two-stage stochastic linear program for the PEV aggregator's day-ahead and balancing decisions with DLC over a large fleet of PEVs, while accounting for conditional value at risk in the objective function. On the other hand, it has put forward a formulation of ILC coordination as a bi-level optimization problem given by mathematical programming with equilibrium constraints, in which 1) the upper level decisions on retail tariffs and optimal bidding in electricity markets are subject to 2) the lower level client-side optimization of PEV charging schedules. These decisions may respect a potential discomfort that could arise when PEV users have to deviate from their preferred charging schedule. Set in an existing, real medium voltage distribution network with urban characteristics and spatial PEV mobility, network UoS tariffs for capacity have been applied to both DLC and ILC scheduling by a PEV aggregator. / Både elkraftsystem och transportsektorn är nödvändiga komponenter av vårt moderna liv – de förstärker den sociala välfärden, möjliggör ekonomisk framgång och bidrar slutligen med välmående för folket. För att undvika skadliga klimateffekter av utsläppta växthusgaser har en rigorös utfasning av fossila bränslen inom båda dessa sektorer prioriterats på politiska agendor runtom i världen. På så vis förväntas elektrifieringen av personbilar bidra till en prisvärd och pålitlig energimodell som ger en acceptabel miljöpåverkan. Med en betydande flexibilitet i efterfrågan på el har elbilarna möjlighet att underlätta integrationen av förnybara energikällor. Frågan är då, hur ska elbilarnas elanvändning koordineras för att bäst bistå elkraftsystemet med hänsyn till resursbrist? Det huvudsakliga syftet med den här forskningen är att föreslå beslutsstödsverktyg som kan förbättra systemeffektiviteten genom elbilsladdning. Forskningen utvecklar en modell för en aggregatoragent som länk till grossistelproducenterna, som antas vara ansvariga för att köpa energi på elmarknaden, under osäkerhet inom priser, tillgång på bilar och efterfrågan. Aggregatorn kan koordinera elbilsladdningen antingen genom direkt efterfrågekontroll, med kraftbegräsningar för enskilda elbilar, eller genom indirekt efterfrågekontroll, men prissignaler. Den här avhandlingen har å ena sidan föreslagit ett tvåstegs stokastiskt linjärt program för elbilsaggregatorns spotmarknads- och balansbeslut med direkt efterfrågekontroll för en stor elbilsflotta, genom att ta hänsyn till conditional value at risk i målfunktionen. Å andra sidan har den tagit fram en formulering för koordinering av indirekt efterfrågekontroll som ett bileveloptimeringsproblem med jämviktsrestriktioner, där 1) de övre besluten om slutkundspriser och optimal budgivning i elmarknaderna med förbehåll för 2) den lägre optimeringen av kundoptimeringen av laddningsscheman. Dessa beslut kan åsamka möjligt obehag för elbilsanvändarna då de behöver avvika från sina föredragna laddningsscheman. Kapacitetsnätverkstariffer har tillämpats både för direkt och indirekt laddningskontroll för en elbilsaggregator, i ett existerande distributionsnätverk med urbana egenskaper och spatiala laddningsscheman för elbilar. / ¿Cómo sería nuestra sociedad moderna, si no existiese el acceso generalizado a la electricidad y cómo viviríamos sin transporte motorizado? Parece muy difícil imaginar nuestras sociedades contemporáneas en países desarrollados sin los sistemas eléctricos como la columna vertebral para incrementar el beneficio social, el desarrollo económico y ultimadamente el bienestar humano. No hay duda que el sector transporte es un constituyente esencial para la vida moderna. Sin embargo, para mitigar los efectos adversos de los gases de efecto invernadero, una rigorosa descarbonización del sector eléctrico y transporte ha sido establecida en la agenda política de muchas partes del mundo. En este sentido, se espera que los vehículos contribuyan a lograr un modelo energético accesible y fiable con un impacto ambiental tolerable. Pero todavía existe una duda: ¿Exactamente cuánto deberían coordinarse los vehículos eléctricos, de tal manera que puedan proveer beneficios al sistema eléctrico en la presencia de escasez de recursos? El principal objetivo de esta investigación es proponer herramientas de soporte que puedan mejorar la eficiencia de todo el sistema a través de la carga de vehículos eléctricos. Un agente agregador podría ser el interfaz con el mercado mayorista de electricidad en la cual el agregador está encargado de comprar energía en los mercados eléctricos exponiéndolo a la incertidumbre de precios, la disponibilidad de la flota de vehículos y los requerimientos de demanda. Este agregador podría coordinar la carga de vehículos eléctricos con control directo de carga (CDC), esto es enviando consignas a los vehículos individuales, o con control indirecto de cargas (CIC), enviando señales de precios minoristas. Esta tesis contribuye con la literatura técnica en dos maneras, por un lado propone una programación lineal en dos etapas con CDC para el agregador de vehículos eléctricos que toma decisiones de oferta en el mercado diario y desvíos de energía para una flota grande de vehículos eléctricos, mientras se tiene en cuenta el valor en riesgo condicional. Por otro lado, se propone una formulación de coordinación con CIC como un problema de optimización binivel dado por una programación matemática con restricciones de equilibrio, donde 1) las decisiones del nivel superior son el diseño de las tarifas minoristas y las ofertas óptimas en los mercados, que dependen de 2) las decisiones de optimización de tiempo de carga de los vehículos eléctricos por parte de los clientes, que se da en un nivel inferior. Las tarifas de red han sido aplicadas a ambos CDC y CIC, estas tarifas están basadas en una red de distribución de media tensión con características urbanas y con movilidad de vehículos eléctricos. / Zowel het elektrische energiesysteem als het transportsysteem leveren een essentiële bij-drage aan de hedendaagse samenleving: het verhogen de maatschappelijke welvaart, het toelaten van economische vooruitgang, en het verbeteren van het menselijke welzijn. Echter, om de nadelige effecten van broeikasgassen te beperken, is een verregaande decarbonisatie van beide sectoren een belangrijk politiek agendapunt geworden in verschillende delen van de wereld. De elektrificatie van personenwagens wordt geacht bij te dragen aan een betaalbaar en betrouwbaar energiemodel dat een aanvaardbare milieu impact heeft. De inherente flex-ibiliteit in de energievraag van plug-in elektrische voertuigen (PEV’s) is beloftevol voor de facilitering van de integratie van hernieuwbare energiebronnen. De vraag is: hoe kan het opladen van PEV’s het best gecoördineerd worden om voordelig te zijn voor het elektrische energiesysteem op momenten van productieschaarste? Het belangrijkste doel van dit onderzoek is om beleidsondersteunende hulpmiddelen aan te bieden, om het totale systeemrendement te verbeteren door middel van het gecoördineerd opladen van PEV’s. Het proefschrift ontwikkelt een model van een aggregatie-agent die als interface fungeert naar de groothandelsmarkt van elektriciteitsproducenten. De aggregator is verantwoordelijk voor de aankoop van de energie op deze elektriciteitsmarkten, en is bij-gevolg blootgesteld aan prijsvolatiliteiten, de beschikbaarheid van de voertuigvloot, en de vereiste energievraag. Deze aggregator kan het opladen van de PEV‘s coördineren via directe lastregeling (Direct Load Control, DLC), het verzenden van de vermogenssetpoints naar de individuele voertuigen, of via indirecte lastregeling (Indirect Load Control, ILC), het sturen van prijssignalen. De bijdrage van dit proefschrift aan de technische vakliteratuur is tweeledig. Ener-zijds wordt er een tweetraps stochastische lineaire programmatiemethode voorgesteld voor de beslissingen van de PEV aggregator op de day-ahead markt en de balanceringsmarkt, waarbij rekening gehouden wordt met het voorwaardelijke risicogehalte van de doelfunctie. Ander-zijds wordt er een formulering van de ILC-coördinatie voorgesteld, als een bi-level optimalisatie probleem dat gebaseerd is op de wiskundige programmeringsmethode met evenwichtsbeperkin-gen. Hierbij zijn er 1) de high-level beslissingen omtrent de retailtarieven en de optimale biedstrategie in de elektriciteitsmarkten, en 2) de low-level optimalisatie van de individuele PEV oplaadschema’s. Deze beslissingen kunnen een mogelijk ongemak creëren door de af-wijking van het optimale laadschema voor de PEV-gebruiker. Voor een realistisch en bestaand stedelijk middenspanning distributienetwerk en ruimtelijk PEV mobiliteitsgedrag, zijn UoS capaciteitstarieven toegepast door een PEV-aggregator, zowel voor DLC- als ILC-gebaseerde laadcoördinatie. / <p>SETS Joint Doctorate</p><p>The Erasmus Mundus Joint Doctorate in Sustainable Energy Technologies and Strategies, the SETS Joint Doctorate, is an international programme run by six institutions in cooperation:</p><p>• Comillas Pontifical University, Madrid, Spain</p><p>• Delft University of Technology, Delft, the Netherlands</p><p>• Florence School of Regulation, Florence, Italy</p><p>• Johns Hopkins University, Baltimore, USA</p><p>• KTH Royal Institute of Technology, Stockholm, Sweden</p><p>• University Paris-Sud 11, Paris, France</p><p>The Doctoral Degrees provided upon completion of the programme are issued by Comillas Pontifical University, Delft University of Technology, and KTH Royal Institute of Technology.</p><p>The Degree Certificates are giving reference to the joint programme. The doctoral candidates are jointly supervised, and must pass a joint examination procedure set up by the three institutions issuing the degrees.</p><p>This Thesis is a part of the examination for the doctoral degree.</p><p>The invested degrees are official in Spain, the Netherlands and Sweden respectively.</p><p>SETS Joint Doctorate was awarded the Erasmus Mundus excellence label by the European Commission in year 2010, and the European Commission’s Education, Audiovisual and Culture Executive Agency, EACEA, has supported the funding of this programme</p><p>The EACEA is not to be held responsible for contents of the Thesis.</p><p>QC 20150923</p>
363

Market-based demand response integration in super-smart grids in the presence of variable renewable generation

Behboodi Kalhori, Sahand 25 April 2017 (has links)
Variable generator output levels from renewable energies is an important technical obstacle to the transition from fossil fuels to renewable resources. Super grids and smart grids are among the most effective solutions to mitigate generation variability. In a super grid, electric utilities within an interconnected system can share generation and reserve units so that they can produce electricity at a lower overall cost. Smart grids, in particular demand response programs, enable flexible loads such as plug-in electric vehicles and HVAC systems to consume electricity preferntially in a grid-friendly way that assists the grid operator to maintain the power balance. These solutions, in conjunction with energy storage systems, can facilitate renewable integration. This study aims to provide an understanding of the achievable benefits from integrating demand response into wholesale and retail electricity markets, in particular in the presence of significant amounts of variable generation. Among the options for control methods for demand response, market-based approaches provide a relatively efficient use of load flexibility, without restricting consumers' autonomy or invading their privacy. In this regard, a model of demand response integration into bulk electric grids is presented to study the interaction between variable renewables and demand response in the double auction environment, on an hourly basis. The cost benefit analysis shows that there exists an upper limit of renewable integration, and that additional solutions such as super grids and/or energy storage systems are required to go beyond this threshold. The idea of operating an interconnection in an unified (centralized) manner is also explored. The traditional approach to the unit commitment problem is to determine the dispatch schedule of generation units to minimize the operation cost. However, in the presence of price-sensitive loads (market-based demand response), the maximization of economic surplus is a preferred objective to the minimization of cost. Accordingly, a surplus-maximizing hour-ahead scheduling problem is formulated, and is then tested on a system that represents a 20-area reduced model of the North America Western Interconnection for the planning year 2024. The simulation results show that the proposed scheduling method reduces the total operational costs substantially, taking advantage of renewable generation diversity. The value of demand response is more pronounced when ancillary services (e.g. real-time power balancing and voltage/frequency regulation) are also included along with basic temporal load shifting. Relating to this, a smart charging strategy for plug-in electric vehicles is developed that enables them to participate in a 5-minute retail electricity market. The cost reduction associated with implementation of this charging strategy is compared to uncontrolled charging. In addition, an optimal operation method for thermostatically controlled loads is developed that reduces energy costs and prevents grid congestion, while maintaining the room temperature in the comfort range set by the consumer. The proposed model also includes loads in the energy imbalance market. The simulation results show that market-based demand response can contribute to a significant cost saving at the sub-hourly level (e.g. HVAC optimal operation), but not at the super-hourly level. Therefore, we conclude that demand response programs and super grids are complementary approaches to overcoming renewable generation variation across a range of temporal and spatial scales. / Graduate / 0791 / sahandbehboodi@gmail.com
364

Guideline for an installation of a charging infrastructure for electric vehicles in Beijing

Hecker, Andreas 16 February 2017 (has links)
Die Arbeit beschäftigt sich mit der Untersuchung von Einflussfaktoren auf eine Ladeinfrastruktur von Elektrofahrzeugen in Peking. Neben den politischen, technischen und wirtschaftlichen Faktoren, liegt der Fokus auf einer Analyse von Nutzerdaten und einer räumlichen Auswertung der Wohn- und Parkplatzsituationen in Peking in Bezug auf die Errichtung einer Ladeinfrastruktur für Elektrofahrzeuge. Der Hauptteil der Arbeit analysiert die städtebauliche Struktur Pekings und kombiniert diese Erkenntnisse mit der Analyse von realen Fahrprofilen von Elektrofahrzeugen. Auf Grund der geringen Anzahl von Parkplätzen sowohl im öffentlichen Raum als auch in den geschlossenen Wohnsiedlungen (Compounds), gestaltet sich die Installation von Ladesäulen, an denen EVs mehrere Stunden laden müssen, als schwierig. Dies betrifft sowohl poly-zentrische als auch mono-zentrische Stadtbezirke im Zentrum. Die Analyse der Fahrprofile basiert auf einem zweiwöchigen Zeitraum mit 60 E-Fahrzeugen, die von Nutzern in Peking gefahren wurden. Ladevorgänge fanden circa 2-3 mal die Woche statt, fanden auf privat Grundstücken statt und dauerten meistens über 10 Stunden. Auf Grund der aufgenommenen GPS-Daten konnte der genaue Aufenthaltsort der Park- und Ladevorgänge untersucht werden. Dabei zeigte sich, dass Fahrzeugführer immer nachts an denselben Orten parkten und luden. Mit den gewonnen Daten konnte auch festgestellt werden, dass home-charging, also das Laden daheim, für die aller meisten Fahrten gänzlich ausreicht. Ergänzt werden kann es durch destination-charging, dem Laden am Zielort, oder on-the-go-charging, dem Laden auf dem Weg zum Zielort. Dabei sind die beiden letzteren Optionen in Peking im halb-öffentlichen Raum anzuordnen, weil reines, öffentliches Laden an Straßenrändern oder Parkplätzen auf Grund von mangelndem Platz nicht möglich sind. / The dissertation deals with the analysis of factors of influence on an implementation of a charging infrastructure for electric vehicles in Beijing. Next to the political, technical and economic factors, the focus is on an analysis of user data and on a spatial analysis of residential housing and parking situations in Beijing. All analyses were done in relation to the implementation of a charging infrastructure for electric vehicles. The main part of the work analyzes the urban structure of Beijing and combines its findings with the analysis of driving profiles of electric vehicles. Due to the small number of parking spaces in public spaces as well as in closed housing estates, the installation of charging stations, becomes a challenge. This concerns both poly-centric and mono-centric city districts in the center of the city. This applies especially to compounds from the 1960s to 1980s, because they were built without adequate parking lots in those days. These properties cannot accommodate the current number of vehicles by far, resulting in the fact that public and semi-public space for parking has to be used. An analysis of the driving profiles is based on a two-week period with 60 electric vehicles driven by real users in Beijing. The investigated vehicles could be charged with alternating current, which prolongs the charging time compared with direct current charging considerably. It was found that most of the parking events took place with relatively full batteries and the distances could be overcome by a single battery charge. Due to the recorded GPS data, the exact location of the parking and charging events could be examined. It was found that EV drivers always parked and charged at night at the same locations. Furthermore it was discovered that home-charging is sufficient for most tracks of the user. This charging type can be extended by destination-charging, or on-the-go-charging.
365

Organosiloxane-Boron Based Liquid Electrolytes for Application in Lithium-Air Batteries

Alzharani, Ahmed A 14 December 2018 (has links)
The synthesis of 2,4,6,8-Tetramethylcyclotetrasiloxane (D4H), and Poly(methylhydrosiloxane) (PMHS) average molecular weight 1700-3200 g/mol, were functionalized with different repeat units of methoxy polyethylene glycol (PEG) (n = 8,12,17). These compounds act as polymer electrolytes with a backbone of siloxane and they were prepared via hydro-silylation reaction to be functionalized with different molecular weights of Ally-PEG. The compounds were confirmed by FT-IR, 1H-NMR and 13C NMR spectroscopy. A hydro-silylation reaction between the functionalized AllyPEG of different molecular weights produced four compounds with a low glass transition temperature that could improve comb like polymer electrolytes conductivity by reducing crystalline phase of PEO. Another way to increase the percentage of the amorphous phase of PEO is to blend it with other polymers. The blending method is considered to be an important method to improve the ionic conductivities and dimensional stability of polymer electrolytes. The main advantages of the blend systems are the simplicity of preparation and the ease to control the physical properties. A high molecular weight of poly 2- vinyl pyridine (Mw=200,000) was added to improve the dimensional stability. Differential scanning calorimetry (DSC) thermal analysis shows that all the blend systems will exhibit an increase in the glass transition temperature by increasing the salt content. The other novel synthesis of polymer electrolytes are triglyme borane and borosilicate. They were synthesized via hydro-boration. These compounds were characterized and confirmed by FT-IR, 1H-NMR 13C NMR spectroscopy. The ionic conductivity of both systems, pure and blend, of different compositions were determined at four temperatures i.e. 25°C, 40°C, 55°C and 70°C. A maximum ionic conductivity value of the siloxane blend is 9.1x10-4 S cm-1 and the pure triglyme borane is 2.14x10-3 S cm-1 at ambient temperature. The ratios of ethylene oxide to lithium salt of siloxane blend and pure triglyme borane were 10:1 and 35:1 respectively. These ratios were the highest conductivity obtained in all the electrolyte systems. The ionic conductivity increases with increasing temperature and salt content to reach optimum concentration. This behavior results in ionic transport, which is supported by the segmental motion of the polymer matrix host.
366

Batalha tecnológica do veículo elétrico: uma análise da corrida automobilística da GM pelo projeto dominante. / Electric vehicle technological battle: an analysis of GM´s automotive race for the dominant design

Chu, Cristina Lau 05 March 2013 (has links)
A presente pesquisa viabilizou, possivelmente, a expansão do arcabouço teórico desenvolvido por Suarez (2004) e Lynn et al. (1996), seguindo a mesma direção dos resultados obtidos na pesquisa longitudinal desenvolvida por Yu et al. (2011). Desenvolvemos um estudo descritivo de modo a analisar um período de 42 anos com o objetivo de entender os fatores que influenciaram a trajetória do desenvolvimento da tecnologia do veículo elétrico na GM de modo que utilizamos o arcabouço teórico desenvolvido por Suarez (2004) como norteador das observações empíricas. Coletamos dados secundários da tecnologia de baterias referente a fase um (realização de P&D) e dados secundários da tecnologia do veículo elétrico referente às fases dois (protótipos) e fase três (criação de mercado) para a construção do estudo de caso. As observações dessas fases viabilizaram os seguintes resultados: a possível expansão do arcabouço conceitual do Suarez (2004) em relação ao nível da firma (sondagem e aprendizagem tecnológica, sondagem e aprendizagem mercadológica e transferência de conhecimento) e ao nível do ambiente (setores industriais associados, pressão social, política internacional e questão econômica); e a possível ampliação da vertente teórica de sondagem e aprendizagem mercadológica desenvolvida por Lynn et al. (1996) no sentido de constatarmos a sondagem e aprendizagem tecnológica em um momento anterior a sondagem e aprendizagem mercadológica. Na década passada, iniciou-se um processo de efervescência de novos entrantes na indústria do veículo elétrico e, nessa década, duas das principais montadoras mundiais (GM e Nissan) lançaram os seus primeiros veículos elétricos para serem produzidos em larga escala. Essas evidências empíricas indicam uma possibilidade real da tecnologia do veículo elétrico estar em um estágio de maturidade que viabilize a realização do processo de transição tecnológica indicada no arcabouço conceitual desenvolvido por Utterback e Abernathy, em 1975. Nesse sentido, os resultados teóricos obtidos nessa pesquisa podem apoiar o processo de tomada de decisão no contexto de incentivo a essa tecnologia tanto da perspectiva da firma quanto da perspectiva do governo. / In alignment with the results obtained in the longitudinal research conducted by Yu et al. (2011), the present study possibly enabled the expansion of the theoretical framework developed by Suarez (2004) and Lynn et al. (1996). A descriptive study was developed so as to analyse a 42 year period with views to understanding the factors which influenced the course of development of electric vehicle technology at GM. Thus, to guide empirical observations, the theoretical framework developed by Suarez (2004) was employed. To build the study case, phase one (execution of R&D) battery technology and phase two (prototypes) and three (market shaping) electric vehicle technology secondary data was collected. Findings observed in these phases gave rise to the following results: the possible expansion of Suarez´s (2004) conceptual framework at corporate level (technological survey and learnings, market survey and learnings and knowledge transfer) and at environment level (associated industrial segments, social pressure, international politics and economic issues); and the possible extension of the theoretical market probe and learning line of thought developed by Lynn et al. (1996) in as much as the identification of the occurrence of technological probe and learning, at a moment preceding that of market probe and learning, is concerned. Over the last decade, a new entrant commotion process sprung within the electric vehicle industry and during this decade, two of the top world manufacturers (GM and Nissan) launched their first electrical vehicles for mass production purposes. This empirical evidence indicates that currently, there is an effective possibility of electric vehicle technology being at a stage of maturity whereby the technological transition mentioned in the conceptual framework developed by Utterback and Abernathy in 1975, is feasible. To this effect, the theoretical results obtained in this study may support decision processes in as much as incentives are concerned, both from a corporate and government perspective.
367

Augmented Framework for Economic Viability-Based Powertrain Design and Emissions Analysis of Medium/Heavy-Duty Plug-in Hybrid Electric Vehicles

Vaidehi Y. Hoshing (5929763) 17 January 2019 (has links)
<div>Plug-in hybrid electric vehicles (PHEVs) are being considered as an alternative to conventional medium-duty (MD) and heavy-duty (HD) commercial vehicles to reduce fuel consumption and tailpipe emissions. Lithium ion batteries, which are used in PHEVs due to their high energy density, are expensive. The battery contributes significantly towards the life-cycle cost of MD/HD PHEVs, as these vehicles, due to high mass and aggressive battery usage, require multiple battery replacements over their lifetime. Smaller batteries increase the fuel consumption and need more replacements, while bigger batteries increase the initial system cost. Powertrain design from a life-cycle cost perspective is required to explore this trade-off and maximize the economic gains obtained from PHEVs. </div><div><br></div><div>Powertrain design entails component sizing, control strategy selection as well as architecture selection. Different powertrain designs yield different lifetime economic gains. A variety of applications exist for MD/HD vehicles, which differ in their ways of powertrain usage, due to variations in required acceleration, available braking, and average and maximum speeds. Therefore, different powertrain designs are needed depending on the application and usage scenario. The powertrain design space needs to be explored, and solutions that maximize the economic gains within the specified constraints need to be chosen.</div><div><br></div><div>This dissertation compares the economic viability of two PHEV applications (MD Truck and HD Transit Bus), with options of series and parallel hybrid architectures, over multiple drivecycles, for four economic scenarios (years 2015, 2020, 2025 and 2030). It is shown that hybridizing the transit bus achieves payback sooner than hybridizing the truck. Further, the results for the transit bus application, over the Manhattan drivecycle, show that implementation of the parallel architecture is economically viable in the 2015(present) scenario, while the series architecture becomes viable in 2020, due to significantly lower initial costs involved in the parallel architecture.</div><div><br></div><div>A methodology to select a solution out of the explored design space that maximizes the economic gains is demonstrated. Variations in the economic and vehicle usage conditions for which this solution is designed, can be expected. It is therefore necessary to check the robustness of this solution to change in external factors such as vehicle mass, annual vehicle miles travelled (AVMT), component and fuel costs. It is shown that the economic gains are affected by the battery cost, fuel cost, AVMT and vehicle mass, while the number of battery replacements are affected by AVMT and vehicle mass. </div><div><br></div><div>A probability-based approach is demonstrated to obtain confidence in the economic and battery life predictions. Specifically, probability-based variations are provided to variables such as miles traveled between recharge, recharge C-rate and battery temperature. It is shown that battery life is affected the most by battery temperature.</div><div><br></div><div>A battery heating/cooling system is required to maintain constant battery temperature of operation during all seasons, but these systems incur additional fuel costs. A framework that utilizes just the Coefficient of Performance (COP) of the heating/cooling system to calculate the excess fuel cost is proposed and demonstrated. An increase of 0.9-1.8\% in fuel consumption is shown, depending on the drivecycle and ambient temperature.</div><div><br></div><div>Further, the well-to-wheel (WTW) fuel-cycle emissions from conventional and PHEV transit buses operating in Indiana and California are assessed using the ``Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation'' (GREET) Model 2017, developed by Argonne National Labs. It is shown that 59% and 63% greenhouse gas (GHG) reductions can be achieved in Indiana and California respectively, along with reduction in carbon monoxide (CO), nitrogen oxides NOx, particulate matter with diameter less than 2.5 microns PM2.5 and volatile organic compounds (VOC) emissions for both the states. However, an increase in sulfur oxides SOx emissions for both the states, and particulate matter with diameter less than 10 microns PM10 increase for Indiana, are observed. </div><div><br></div>
368

Projeto e dimensionamento de um sistema de tração para veículos elétricos

Wiltuschnig, Igor Pasa January 2016 (has links)
O presente trabalho tem por objetivo propor uma metodologia para o dimensionamento da potência tracionária em função do percurso percorrido por veículos elétricos, assim como realizar o projeto básico de uma máquina elétrica para suprir a carga tracionária exigida. Os cálculos foram realizados através de um algoritmo onde o usuário insere as variáveis mecânicas do veículo e recebe a potência e conjugado necessários, e o projeto elementar da máquina que deverá equipar o veículo. Realizou-se um estudo de caso a partir de uma scooter elétrica para validar os resultados, foi projetada uma máquina brushless dc com fluxo radial e rotor externo. Os resultados experimentais atenderam as espectativas de conjugado de 46 Nm, o máximo conjugado estático atingiu 48 Nm e a rotação a vazio obteve valor de 613 rpm à tensão nominal. Os ensaios de frenagem regenerativa com supercapacitores apresentaram resultados promissores com 50% da energia mecânica recebida durante a frenagem entregue na partida do veículo. / The present study aims to propose a methodology for the design of power traction depending on the distance traveled by electrical vehicles, and perform the basic design of an electrical machine to supply the traction load required. The calculations will be performed through an algorithm where the user enters the mechanical variables of the vehicle and receives the power and torque required and the basic machine design that should equip the vehicle. A case study was conducted for an electric scooter considering the designed dc brushless machine with radial flow and external rotor in order to validate the results. The experimental results met the target of 46 Nm of torque, the maximum static torque 48 Nm was reached, and the no-load rotation obtained was 613 rpm at nominal voltage. Regenerative braking tests with super capacitors showed a promising result: 50% of the received mechanical energy during braking was delivered to the vehicle starting.
369

Carregador de Baterias MonofÃsico Para AplicaÃÃo em VeÃculos ElÃtricos / âSingle-Phase Battery Charger Feasible for Electric Vehicles Applicationsâ,

CÃsar Orellana Lafuente 28 June 2011 (has links)
Este trabalho apresenta o estudo de um carregador de baterias monofÃsico aplicado a veÃculos elÃtricos. Este carregador à composto por dois estÃgios de processamento de energia e um circuito digital de supervisÃo para controlar a tensÃo sobre o banco de baterias e a corrente de recarga das mesmas. O primeiro estÃgio consiste de um conversor CA-CC bridgeless com caracterÃstica de alto fator de potÃncia, e o segundo estÃgio à representado por um conversor CC-CC fullbridge com isolamento em alta frequÃncia e comutaÃÃo sob tensÃo nula (Zero Voltage Switching â ZVS). Para ambos os conversores, foi realizada uma anÃlise qualitativa e quantitativa, bem como apresentados exemplos de projeto para facilitar o dimensionamento dos componentes. Finalmente, com os componentes escolhidos, foi montado um protÃtipo que permite carregar de uma atà oito baterias de 12 V conectadas em sÃrie. O sistema apresenta como especificaÃÃes: tensÃo de entrada alternada de 220 VÂ15%; tensÃo de saÃda contÃnua de 120 V; corrente de saÃda contÃnua de 20 A; e potÃncia mÃdia de saÃda de 2,4 kW. / This work presents a single-phase battery charger for electric vehicles. This converter is composed by two energy processing stages and a digital circuit to control the voltage across the batteries and their respective charging current. The first stage is a high power factor ACDC bridgeless converter, while the second one consists on a ZVS (Zero Voltage Switching) high frequency isolated DC-DC full-bridge converter. For both converters, the qualitative and quantitative analyses have been performed, as well as design examples have been presented in order to ease the components calculation. Finally, a prototype that allows charging up to eight series-connected 12 V batteries has been built. The system specifications are: AC input voltage of 220 V Â15%; DC output voltage of 120 V; DC output current of 20 A; and average output power of 2.4 kW.
370

Avaliação de impactos da inserção dos veículos elétricos nos sistemas de distribuição das concessionárias EDP Bandeirante e EDP ESCELSA. / Evaluation of the electric vehicles impact on the distribution systems of the EDP Bandeirante and EDP ESCELSA utilities.

João Paulo Niggli Silva 21 March 2014 (has links)
O objetivo deste trabalho é avaliar qual seria o impacto da inserção dos veículos elétricos nos sistemas de distribuição de energia elétrica de duas distribuidoras brasileiras, a EDP Bandeirante e EDP ESCELSA. Como esta tecnologia ainda não se encontra em utilização no Brasil, será adotada uma abordagem prospectiva, de modo a projetar o crescimento da frota de veículos elétricos até o ano de 2020. Para que se possa simular em uma sub estação, qual será o impacto da adoção desta tecnologia. Utilizando-se das projeções de crescimento da frota, também serão quantificados o impacto na matriz energética nacional e nas emissões de gases do efeito estufa. / This work, aims to evaluate the impact of the electric vehicles insertion on two power distribution utilities, EDP Bandeirante and EDP ESCELSA. How the electric vehicles aren´t a reality on Brazil, an prospective approach will be adopted, to project the growth of the electric vehicles fleet until the 2020 year, so that can be simulated in one substation, the impact that would be caused by the adoption of this technology. Using these projections, the impact on Brazilian energetic matrix, and the greenhouse gas emissions will be calculated to.

Page generated in 0.0529 seconds