• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 43
  • 14
  • 7
  • 5
  • 3
  • 3
  • 3
  • 1
  • 1
  • 1
  • Tagged with
  • 89
  • 89
  • 31
  • 28
  • 23
  • 22
  • 18
  • 16
  • 16
  • 16
  • 14
  • 13
  • 13
  • 12
  • 12
  • 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.
51

Design and Control the Ancillary System for Hydraulic Hybrid Vehicle (HHV)

Abdelgayed, Mohamed E. 09 September 2010 (has links)
No description available.
52

Desenvolvimento e demonstração de funcionamento de um sistema híbrido de geração de energia elétrica, com tecnologia nacional composto por um módulo de células a combustível tipo PEMFC e acumulador chumbo ácido / Hybrid system development and operation for an electric power generation with the brazilian technology composed of a PEMFC fuel cell stack and lead acid battery

Senna, Roque Machado de 26 June 2012 (has links)
Este trabalho apresenta a contribuição obtida no desenvolvimento de um Gerador de Eletricidade Híbrido (HYBRIDGEN), com tecnologia nacional, focado nos sistemas de terceira geração de energia elétrica híbrido, composto por um módulo de células a combustível tipo PEMFC, associado a um acumulador chumbo ácido. Mostra-se também a sua capacidade de operar em modo contínuo, carga com demanda variável e fator de carga inferior a 50%. Foram abordados quatro temas principais. O primeiro refere-se a um estudo para a melhoria da eficácia na conversão de energia em corrente contínua (cc), ao regular o potencial de saída do conversor cc-cc. A energia é proveniente do módulo de célula a combustível de 1 kWe, equipado com sistema térmico de refrigeração e sistema de alimentação de gases, aqui denominados MCC1. Para tal, foi construído o modelo matemático do sistema conversor de corrente contínua (sistema conversor cc-cc), com solução suportada em equações diferenciais algébricas, ensaios no MCC1, bem como em simulação computacional no programa MATLAB7®. O segundo tema refere-se ao desenvolvimento do projeto e montagem do protótipo do HYBRIDGEN devido à inexistência no mercado brasileiro de um equipamento com as características necessárias tanto para a pesquisa, quanto para uso comercial. Desenvolveu-se uma placa controladora para o acumulador (PCC), os esquemas elétricos, os barramentos e o sistema de relés. Também foi utilizado o MCC1 em desenvolvimento pelo IPEN e ELECTROCELL® com tecnologia 100% nacional. O HYBRIDGEN foi instalado em um sistema móvel. O terceiro tema refere-se à análise de estabilidade do modelo matemático do sistema conversor cc-cc. Utilizou-se de quatro testes de estabilidade, sendo: 1 - pela Resposta em Frequência ao utilizar o Teorema do Mapeamento, de Nyquist; 2 - Lugar das Raízes, de Nyquist; 3 - função de teste Degrau, em pontos de operação e, 4 - função de teste Impulso, em pontos de operação. Por fim, apresentaram-se os resultados dos ensaios de potencial e corrente de uma célula a combustível unitária de 25 cm2, do MCC1, e do HYBRIDGEN. No desenvolvimento dos primeiros testes o MCC1 atingiu 704,55 We, (potência considerada condição predominante de operação). A seguir, demonstrou-se a capacidade do HYBRIDGEN para simultaneamente: alimentar cargas em corrente contínua; carregar o acumulador de 45 Ah; alimentar o inversor de 2 kWe e o autotransformador, para fornecer energia a equipamentos em 12Vcc, 127 Vac e 220Vac, 60 Hz, todos num total de 819,52 We. Esses resultados foram obtidos mesmo com limitações na refrigeração ventilada do MCC1, observadas no decorrer dos testes. Assim, o HYBRIDGEN se mostrou viável tecnicamente, e com grande potencial de uso. / This work presents the contribution obtained by the development of the Hybrid Electric Power Generation System (HYBRIDGEN), with Brazilian technology, focused on third generation hybrid system, composed of the fuel cell type PEMFC, associated with a lead acid battery, and shows its variable load demand continuous mode operate ability with load factor below 50%. Four main themes were addressed. The first refers to a study concerning the to direct current (DC) energy converting efficiency improvement to regulate the dc-dc converter output potential. Power comes from the 1 kWe fuel cell stack, equipped with thermal cooling system and gas supply system, here named MCC1. After that a dc-dc converter system mathematical model was built supported on differential algebraic equations solution, the MCC1 trials, as well as in MATLAB7® program computer simulation. The second theme concerns the HYBRIDGEN prototype project and assembly due to lack on equipment on the Brazilian market with the necessary features for both research and for commercial use. Then, a charge controller card (CCC), wiring diagrams, copper bus and relay system were developed. A MCC1 developed by IPEN and ELECTROCELL® with Brazilian technology was use. The HYBRIDGEN can be installed in a mobile system. The third refers to a study concerning the stability analysis of the dc-dc converter system mathematical model. Four stability tests were addressed, namely: 1- The Frequency Response was used the Nyquist Mapping Theorem, 2 - The Nyquist Root Locus , 3 - The Step Test Function on operating points, and 4 - The Impulse Test Function on operating points. Finally, experiments with a 25 cm2 fuel cell unit, the MCC1 module and the HYBRIDGEN were carried out to, potential and current results. In the first MCC1 tests delivered a power output of 704.55 W (considered dominant operation power). Then, it was demonstrated the HYBRIDGEN ability to 819.52 We supply power, simultaneously: direct current loads, charge a 45Ah battery, a 2 kWe inverter and the autotransformer to supply power 12 Vcc, 127Vac, 220Vac, 60 Hz equipment. These results were achieved despite the MCC1 limit in the cooling system observed during the tests. Then, the HYBRIDGEN could be demonstrated technically feasible, and leading to great potential uses.
53

Optimization of the sizing and the energy management for a hybrid fuel cell vehicle including fuel cell dynamics and durability constraints / Optimisation du dimensionnement et de la gestion d'énergie d'un véhicule à pile à combustible intégrant les contraintes de dynamiques et de durabilité

Fonseca, Ramon, Naiff da 10 October 2013 (has links)
L'hydrogène à travers de l'utilisation des piles à combustible (PAC), est de plus en plus considéré comme une option énergétique possible au secteur des transports grâce à ces caractéristiques fonctionnelles. Cependant, la technologie liée à la mise en œuvre de véhicules alimentés par une pile à combustible n'a pas encore atteint le niveau de maturité requis. Ainsi, ce travail propose de traiter certaines de ces limitations qui existent encore. Plus précisément, trois thèmes représentent les objectifs de ce travail : Le dimensionnement optimal des éléments présents dans un véhicule hybride à pile à combustible. La gestion d'énergie optimale pour les applications en temps réel et intégrant les contraintes dynamiques du système PAC. Inclusion de la durabilité de la pile à combustible dans la gestion d'énergie du véhicule. Le premier thème est abordé à travers l'élaboration d'une méthodologie de dimensionnement adapté à un véhicule hybride à la pile à combustible. Dans une approche systématique, le dimensionnement proposé combine les exigences de performance présente dans les spécifications techniques du véhicule, les algorithmes d'optimisation, l'analyse de la mobilité de la population et la viabilité économique de la conception. Le deuxième objectif établi a été développé à l'aide d'une approche d'optimisation de la répartition de puissance entre la batterie et le système PAC. Par l'adoption d'une méthode d'optimisation globale combinée à une stratégie de commande prédictive et l'inclusion de la dynamique du système PAC, un algorithme de gestion d'énergie pour des applications de temps réel a été conçu. Enfin, la durabilité de la pile à combustible a été incluse dans ce travail par l'intégration de sa dynamique de dégradation dans le problème d'optimisation lié à la gestion d'énergie. Cette dynamique représente une contrainte à prendre en considération lors de la répartition de puissance entre le système PAC et la batterie. / The hydrogen, through the use of fuel cell stacks (FC), has been increasily considered as an energy possible option for the transport sector. Nevertheless, the technology related to its implementation in fuel cell vehicles has not reached the required maturity level. Therefore, this work intends to deal some of these existing limitations. More precisely, three topics represent the objectives of this work: The optimal sizing of the element present in the fuel cell hybrid vehicle. The development of an optimal energy management strategy oriented for real time applications and including the dynamic constraints of the FC system. The inclusion of the fuel cell durability in the vehicle energy management strategy. The first topic is tackled by the development of a sizing methodology adapted to the fuel cell hybrid vehicle application. Using a systematic approach, the proposed sizing method combine the performance requirements present in the vehicle's technical specifications, optimization algorithms, population mobility behavior and the economic viability of the design. The second assigned objective was developed using an optimization approach for the power split between the battery and the FC system. Through the adoption of a global optimization method allied with a predictive control strategy and the inclusion of the FC system dynamics, it was created an energy management algorithm oriented for real time applications. Finally, the fuel cell durability was included in this work by the integration of its degradation dynamics in the optimization problem, which is related to the vehicle's energy management. Such dynamic represents a constraint that should be taken into account in the power sharing between the FC system and battery
54

Development of simulation tools, control strategies, and a hybrid vehicle prototype

Pei, Dekun 14 November 2012 (has links)
This thesis (1) reports the development of simulation tools and control strategies for optimizing hybrid electric vehicle (HEV) energy management, and (2) reports the design and testing of a hydraulic hybrid school bus (HHB) prototype. A hybrid vehicle is one that combines two or more energy sources for use in vehicle propulsion. Hybrid electric vehicles have become popular in the consumer market due to their greatly improved fuel economy over conventional vehicles. The control strategy of an HEV has a paramount effect on its fuel economy performance. In this thesis, backward-looking and forward-looking simulations of three HEV architectures (parallel, power-split and 2-mode power-split) are developed. The Equivalent Cost Minimization Strategy (ECMS), which weights electrical power as an equivalent fuel usage, is then studied in great detail and improvements are suggested. Specifically, the robustness of an ECMS controller is improved by linking the equivalence factor to dynamic programming and then further tailoring its functional form. High-fidelity vehicle simulations over multiple drive-cycles are performed to measure the improved performance of the new ECMS controller, and to show its potential for online application. While HEVs are prominent in the consumer market and studied extensively in current literature, hydraulic hybrid vehicles (HHVs) only exist as heavy utility vehicle prototypes. The second half of this thesis reports design, construction, and testing of a hydraulic hybrid school bus prototype. Design considerations, simulation results, and preliminary testing results are reported, which indicate the strong potential for hydraulic hybrids to improve fuel economy in the school bus vehicle segment.
55

Optimierung des Betriebsverhaltens und der Konfiguration von dieselelektrischen Lokomotiven

Schimke, Robert 20 June 2013 (has links) (PDF)
Diese Arbeit entstand an der Professur für Fahrzeugmodellierung und –simulation der TU Dresden in Zusammenarbeit mit der Fa. Bombardier Transportation („Bombardier Center of Competence“). In einem Teilprojekt dieser Kooperation wird die Einführung technischer Funktionen und Systeme zur Energieeinsparung bei Lokomotiven untersucht. Die Nutzung von Speichertechnologien ist neben der Abwärmenutzung und der energiesparenden Fahrweise die effizienteste Maßnahme zur Senkung des Kraftstoffverbrauchs bei Dieselfahrzeugen. Zusätzlich zur Rekuperation von Bremsarbeit können die Funktionen Lastpunktverschiebung und emissionsfreier Betrieb mit Hilfe eines Energiespeichers realisiert werden. Der Einsatz elektrischer Energiespeicher erweist sich als geeignet für dieselelektrische Schienenfahrzeuge im Personenverkehr, da diese durch die bereits vorhandenen elektrischen Antriebskomponenten relativ einfach zu hybridisieren sind und eine nutzungsgerechte Speicherauslegung aufgrund weitgehend bekannter Fahraufgaben möglich ist. In der Arbeit wird ein durchgängiges Verfahren zur Auslegung von dieselelektrischen Lokomotiven mit Energiespeichern im Personenverkehr beschrieben. Im Fokus liegt dabei der Einsatz von Optimierungsalgorithmen zur Verbesserung des Generatorsystems und des Einsatzes von elektrischen Energiespeichern im Hinblick auf den Kraftstoffverbrauch und die weiteren Anteile der Lebenszykluskosten. Das im Rahmen der Arbeit erstellte Programm zur energetischen Simulation bildet die Basis zur Untersuchung verschiedener Strategien für die Fahrtgestaltung unter Berücksichtigung der Fahrzeitreserven, den Betrieb des Energiespeichers und der Steuerung von Anlagen mit mehreren Dieselmotorgeneratorsätzen. Neben der Nutzung regelbasierter Strategien werden dabei auch vorausschauende Betriebsstrategien eingesetzt, welche die Möglichkeiten der bei Schienenfahrzeugen im Vorfeld bekannten Streckengeschwindigkeit und -topologie nutzen. Die dafür angewandten Methoden sind die Dynamische Programmierung nach BELLMANN und der äquivalenzkostenbasierte Betrieb. Die Optimierung der Fahrzeugkonfiguration wird durch einen Programmbaustein realisiert, welcher unter Berücksichtigung der Lokkonfiguration und der Energiesimulation für ein vorgegebenes Streckenprofil die Verbrauchs-, Instandhaltungs- und Anschaffungskosten für das Fahrzeug berechnet.
56

Optimal energy utilization in conventional, electric and hybrid vehicles and its application to eco-driving

Mensing, Felicitas 03 October 2013 (has links) (PDF)
The transportation sector has been identified as one of many sources of today's energetic and environmental problems. With constantly increasing numbers of vehicles on the road, non-renewable fossil fuels are becoming scarce and expensive. In addition, due to the pollutant emissions of internal combustion engines, the transportation sector is a major producer of greenhouse gas emissions. To resolve these problems researcher are looking for technological solutions, such as more efficient components and alternative drive train technologies, on one hand. On the other hand, work is being done to ensure the most efficient utilization of available technological resources. Eco driving is one way to immediately reduce a driver's energy consumption. In this thesis the potential gains of eco driving for passenger vehicles will be discussed. The main objective of this work is to, first, identify and compare drive train specific, optimal vehicle operation. Secondly, the effect of real-life constraints on potential gains of eco driving is evaluated. In addition, an approach to integrate mathematical optimization algorithms in an advanced driver assist system for eco driving is proposed. Physical vehicle models are developed for three representative vehicles: the conventional, electric and power-split hybrid vehicle. Using real-life and standard drive cycles a baseline mission is defined by specifying trip and road constraint. Applying the dynamic programming algorithms the trajectory optimization problem is solved, minimizing energy consumption for the trip. The effect of traffic on potential gains of eco driving is discussed, considering a vehicle following situation. Integrating emission constraints in the optimization algorithm the environmental advantages of eco driving are discussed. Finally, the developed algorithms were integrated in a driver assist system. Experimental tests on a driving simulator were used to verify the effectiveness of the system, as well as driver acceptance.
57

Modeling and simulation of hybrid electric vehicles

Zhou, Yuliang Leon 14 January 2008 (has links)
With increasing oil price and mounting environment concerns, cleaner and sustainable energy solutions have been demanded. At present transportation constitutes a large portion of the energy consumed and pollution created. In this work, two hybrid vehicle powertrain technologies were studied, a fuel cell - battery hybrid and two internal combustion engine - battery/ultracapacitor hybrids. Powertrain performance models were built to simulate the performance of these new designs, and to assess the feasibility of a fuel cell hybrid power backup system for a special type of vehicles, elevators in high-rise buildings, using the ADvanced VehIcle SimulatOR (ADVISOR) first. The model was then applied to evaluate the two-mode hybrid powertrain for more common vehicles - commercial trucks, showing potential fuel consumption reduction. To improve modeling accuracy, a new and more flexible tool for modeling multi-physics systems, Modelica/Dymola, was used to carry out the modeling and analysis of next generation hybrid electric vehicles, exploring the potentials of new hybrid powertrain architectures and energy storage system designs. The study forms the foundation for further research and developments.
58

Evaluating methods for multi-level system design of a series hybrid vehicle

Taylor, Brian Jonathan Hart 05 July 2012 (has links)
In design and optimization of a complex system, there exist various methods for defining the relationship between the system as a whole, the subsystems and the individual components. Traditional methods provide requirements at the system level which lead to a set of design targets for each subsystem. Meeting these targets is sometimes a simple task or can be very difficult and expensive, but this is not captured in the design process and therefore unknown at the system level. This work compares Requirements Allocation (RA) with Distributed Value Driven Design (DVDD). A computational experiment is proposed as a means of evaluating RA and DVDD. A common preliminary design is determined by optimizing the utility of the system, and then a Subsystem of Interest (SOI) is chosen as the focal point of subsystem design. First the behavior of a designer using Requirements Allocation is modeled with an optimization problem where the distance to the design targets is minimized. Next, two formulations of DVDD objective functions are used to approximate the system-level value function. The first is a linear approximation and the second is a nonlinear approximation with higher fidelity around the preliminary design point. This computational experiment is applied to a series hybrid vehicle where the SOI is the electric motor. In this case study, RA proves to be more effective than DVDD on average. It is still possible that the use of objectives is superior to design targets. This work shows that, for this case study, a linear approximation as well as a slightly higher fidelity approximation are not well suited to find the design alternative with the highest expected utility.
59

Desenvolvimento e demonstração de funcionamento de um sistema híbrido de geração de energia elétrica, com tecnologia nacional composto por um módulo de células a combustível tipo PEMFC e acumulador chumbo ácido / Hybrid system development and operation for an electric power generation with the brazilian technology composed of a PEMFC fuel cell stack and lead acid battery

Roque Machado de Senna 26 June 2012 (has links)
Este trabalho apresenta a contribuição obtida no desenvolvimento de um Gerador de Eletricidade Híbrido (HYBRIDGEN), com tecnologia nacional, focado nos sistemas de terceira geração de energia elétrica híbrido, composto por um módulo de células a combustível tipo PEMFC, associado a um acumulador chumbo ácido. Mostra-se também a sua capacidade de operar em modo contínuo, carga com demanda variável e fator de carga inferior a 50%. Foram abordados quatro temas principais. O primeiro refere-se a um estudo para a melhoria da eficácia na conversão de energia em corrente contínua (cc), ao regular o potencial de saída do conversor cc-cc. A energia é proveniente do módulo de célula a combustível de 1 kWe, equipado com sistema térmico de refrigeração e sistema de alimentação de gases, aqui denominados MCC1. Para tal, foi construído o modelo matemático do sistema conversor de corrente contínua (sistema conversor cc-cc), com solução suportada em equações diferenciais algébricas, ensaios no MCC1, bem como em simulação computacional no programa MATLAB7®. O segundo tema refere-se ao desenvolvimento do projeto e montagem do protótipo do HYBRIDGEN devido à inexistência no mercado brasileiro de um equipamento com as características necessárias tanto para a pesquisa, quanto para uso comercial. Desenvolveu-se uma placa controladora para o acumulador (PCC), os esquemas elétricos, os barramentos e o sistema de relés. Também foi utilizado o MCC1 em desenvolvimento pelo IPEN e ELECTROCELL® com tecnologia 100% nacional. O HYBRIDGEN foi instalado em um sistema móvel. O terceiro tema refere-se à análise de estabilidade do modelo matemático do sistema conversor cc-cc. Utilizou-se de quatro testes de estabilidade, sendo: 1 - pela Resposta em Frequência ao utilizar o Teorema do Mapeamento, de Nyquist; 2 - Lugar das Raízes, de Nyquist; 3 - função de teste Degrau, em pontos de operação e, 4 - função de teste Impulso, em pontos de operação. Por fim, apresentaram-se os resultados dos ensaios de potencial e corrente de uma célula a combustível unitária de 25 cm2, do MCC1, e do HYBRIDGEN. No desenvolvimento dos primeiros testes o MCC1 atingiu 704,55 We, (potência considerada condição predominante de operação). A seguir, demonstrou-se a capacidade do HYBRIDGEN para simultaneamente: alimentar cargas em corrente contínua; carregar o acumulador de 45 Ah; alimentar o inversor de 2 kWe e o autotransformador, para fornecer energia a equipamentos em 12Vcc, 127 Vac e 220Vac, 60 Hz, todos num total de 819,52 We. Esses resultados foram obtidos mesmo com limitações na refrigeração ventilada do MCC1, observadas no decorrer dos testes. Assim, o HYBRIDGEN se mostrou viável tecnicamente, e com grande potencial de uso. / This work presents the contribution obtained by the development of the Hybrid Electric Power Generation System (HYBRIDGEN), with Brazilian technology, focused on third generation hybrid system, composed of the fuel cell type PEMFC, associated with a lead acid battery, and shows its variable load demand continuous mode operate ability with load factor below 50%. Four main themes were addressed. The first refers to a study concerning the to direct current (DC) energy converting efficiency improvement to regulate the dc-dc converter output potential. Power comes from the 1 kWe fuel cell stack, equipped with thermal cooling system and gas supply system, here named MCC1. After that a dc-dc converter system mathematical model was built supported on differential algebraic equations solution, the MCC1 trials, as well as in MATLAB7® program computer simulation. The second theme concerns the HYBRIDGEN prototype project and assembly due to lack on equipment on the Brazilian market with the necessary features for both research and for commercial use. Then, a charge controller card (CCC), wiring diagrams, copper bus and relay system were developed. A MCC1 developed by IPEN and ELECTROCELL® with Brazilian technology was use. The HYBRIDGEN can be installed in a mobile system. The third refers to a study concerning the stability analysis of the dc-dc converter system mathematical model. Four stability tests were addressed, namely: 1- The Frequency Response was used the Nyquist Mapping Theorem, 2 - The Nyquist Root Locus , 3 - The Step Test Function on operating points, and 4 - The Impulse Test Function on operating points. Finally, experiments with a 25 cm2 fuel cell unit, the MCC1 module and the HYBRIDGEN were carried out to, potential and current results. In the first MCC1 tests delivered a power output of 704.55 W (considered dominant operation power). Then, it was demonstrated the HYBRIDGEN ability to 819.52 We supply power, simultaneously: direct current loads, charge a 45Ah battery, a 2 kWe inverter and the autotransformer to supply power 12 Vcc, 127Vac, 220Vac, 60 Hz equipment. These results were achieved despite the MCC1 limit in the cooling system observed during the tests. Then, the HYBRIDGEN could be demonstrated technically feasible, and leading to great potential uses.
60

Étude et modélisation du vieillissement des supercondensateurs en mode combiné cyclage/calendaire pour applications transport / Study and modeling of the ageing of supercapacitors in combined cycling/calendar mode for transportation applications

Ayadi, Mohamed 30 June 2015 (has links)
Dans le but de l’intégration des supercondensateurs dans des applicationstransport, la connaissance et l’étude de leur comportement au cours du vieillissementest nécessaire. L’objectif de cette thèse est donc la compréhension et lamodélisation des phénomènes de vieillissement observés sur lessupercondensateurs. Pour cela, des méthodologies de caractérisation électriques etdes protocoles expérimentaux originaux combinant les différentes contraintes devieillissement ont été mis en oeuvre. Des mesures du courant de fuite et des tests devieillissement combinés ont été effectués. Les résultats obtenus sont présentés. Ilsont ainsi servis au développement et l’implémentation de modèles permettant le suivide l’évolution des performances des supercondensateurs avec le vieillissement. / The study of the behavior of supercapacitors during ageing is required in orderto integrate them in transportation applications. The aim of this thesis is tounderstand and model ageing phenomena observed on supercapacitors. For thispurpose, electrical characterization methodologies and original experimentalprotocols combining various constraints of ageing have been implemented.Measurements of leakage current and combined ageing tests were conducted. Theobtained results were used for developing models allowing the monitoring of theevolution of supercapacitors performance during ageing.

Page generated in 0.0433 seconds