• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 30
  • 21
  • 8
  • 6
  • 6
  • 4
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 97
  • 45
  • 28
  • 24
  • 22
  • 21
  • 20
  • 18
  • 16
  • 14
  • 12
  • 11
  • 10
  • 10
  • 10
  • 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.
31

Cargador Portátil Ecológico MAX - E

Acosta Valverde, Melanie Araceli, Andrade Mariños, Joan Ayrton, Ortiz Chamochumbi, Renzo, Vásquez Calderón, John Erick, Linares Castillo, Diego Alonso 07 July 2020 (has links)
El presente proyecto es un cargador solar ecológico que puede ser transportado en todo momento debido a su tamaño compacto y su poco peso de 150 gramos. Además, almacena la energía del sol y la luz led para luego cargar tu dispositivo en cualquier momento. Se desarrolla su viabilidad en base a una investigación realizada a hombres y mujeres de 18 a 39 años de los niveles socioeconómicos A, B y C. Por lo tanto, el análisis permite identificar a un grupo de personas que necesitan cargar su celular en momentos importantes durante el día pero que no encuentran lugar donde conectarlo o no tienen un cargador. Para validar la solución se utilizó un prototipo del producto el cual fue presentado al público y especialistas para que salga al mercado. Por último, se realizó un concierge para calcular la intención de compra del producto y proyectar sus estados financieros, los cuales, están respaldados por pertinentes desarrollos estratégicos que llevan a cabo un plan de negocio. / This project is an ecological solar charger that can always be transported due to its compact size and low weight of 150 grams. In addition, it stores the energy of the sun and the led light and then charges your device at any time. Its viability is developed based on research carried out on men and women between 18 and 39 years of age from socioeconomic levels A, B and C. Therefore, the analysis allows identifying a group of people who need to charge their cell phones at crucial moments in the day, but they do not find a place to connect it or they do not have a charger. To validate the solution, a prototype of the product was used, which was presented to the public and specialists so that it would be released. Finally, a concierge was held to calculate the intention to purchase the product and to project its financial statements, which are backed by pertinent strategic developments that carry out a business plan. / Trabajo de investigación
32

The Development of an Electric Tricycle and Buck-Topology-Based Battery Pack Charger

Taschner, Matthew John 15 December 2011 (has links)
No description available.
33

Electric Vehicles Fast Charger Location-Routing Problem Under Ambient Temperature

Salamah, Darweesh Ehssan A 06 August 2021 (has links) (PDF)
Electric cars are projected to become the vehicles of the future. A major barrier for their expansion is range anxiety stemming from the limited range a typical EV can travel. EV batteries' performance and capacity are affected by many factors. In particular, the decrease in ambient temperature below a certain threshold will adversely affect the battery's efficiency. This research develops deterministic and two-stage stochastic program model for charging stations' optimal location to facilitate the routing decisions of delivery services that use EVs while considering the variability inherent in climate and customer demand. To evaluate the proposed formulation and solution approach's performance, Fargo city in North Dakota is selected as a tested. For the first chapter, we formulated this problem as a mixed-integer linear programming model that captures the realistic charging behavior of the DCFC's in association with the ambient temperature and their subsequent impact on the EV charging station location and routing decisions. Two innovative heuristics are proposed to solve this challenging model in a realistic test setting, namely, the two-phase Tabu Search-modified Clarke and Wright algorithm and the Sweep-based Iterative Greedy Adaptive Large Neighborhood algorithm. The results clearly indicate that the EV DCFC charging station location decisions are highly sensitive to the ambient temperature, the charging time, and the initial state-of-charge. The results provide numerous managerial insights for decision-makers to efficiently design and manage the DCFC EV logistic network for cities that suffer from high-temperature fluctuations. For the second chapter, a novel solution approach based on the progressive hedging algorithm is presented to solve the resulting mathematical model and to provide high-quality solutions within reasonable running times for problems with many scenarios. We observe that the location-routing decisions are susceptible to the EV logistic's underlying climate, signifying that decision-makers of the DCFC EV logistic network for cities that suffer from high-temperature fluctuations would not overlook the effect of climate to design and manage the respective logistic network efficiently.
34

Integrated Microbattery Charger for Autonomous Systems

Lefevre, Brian W. 09 February 2004 (has links) (PDF)
This thesis presents a microbattery recharging circuit suitable for autonomous microsystems. The battery charger chosen for this design is a constant current battery charger. Two methods of regulating the constant-current are discussed. A published shunt regulator design is analyzed and is presented with enhancements to the design. A series regulator that controls the current to the battery with a switch is designed and fabricated in a 1.5µm CMOS process. The fabricated prototype occupies less than 2.20x2.20mm and is expected to dissipate less than 25µW of power. A discrete model of the integrated circuit is constructed and tested to demonstrate that the series regulator will work using a solar cell as the energy source. The design of the charger is a major step toward the construction of a completely integrated autonomous system.
35

Multiple Input Single Output (MISO) Tablet/ Phone Charger

Wong, Kevin 01 June 2013 (has links) (PDF)
This thesis entails the design and implementation of a multiple input single output (MISO) DC-DC converter using the flyback topology to charge tablets/ smartphones or any USB powered portable device. The MISO converter will enable the use of various renewable energy sources such as a solar panel/ rechargeable battery combination, bicycle dynamo, hydroelectric power, and wind turbine. This paper will cover the design, simulations, and test results of the MISO converter. The flyback topology was chosen due to its low part count and its efficiency at low power. The proposed converter has a nominal 12V input to output USB 2.0 requirements (5V at 2.5W). Results from both computer simulation using LTSpice and hardware tests demonstrate the functionality of the proposed MISO converter with solar/battery and bicycle dynamo inputs. Overall performance of the converter in terms of efficiency, line and load regulations, as well as its charging ability to a cell phone will be presented in this report.
36

Universal Programmable Battery Charger with Optional Battery Management System

Desando, Michael Duke 01 June 2015 (has links) (PDF)
This report demonstrates improvements made in battery charging and battery management technology through the design of a universal programmable battery charger with optional battery management system attachment. This charger offers improvements in charge efficiency and unique battery charging algorithms to charge a variety of battery chemistries with variety of power requirements. Improvements in efficiency result from a synchronous Buck Controller topology as compared to previous universal chargers that use asynchronous Buck-Boost Converter topologies. This battery charger also surpasses current universal battery chargers by offering different charge modes for different battery chemistries. Charge modes provide the user an option between extending the life of the battery by selecting a mode with a slower, less stressful charge rate or a shorter charge time with a fast, more stressful charging mode. The user can also choose a charge mode in which the battery charges to full capacity, resulting in maximum runtime or a less than full capacity, which puts less stress on the battery thus extending the lifetime. Ultimately, this system permits weighing the performance tradeoff of battery lifetime and charge time. The optional battery management system attachment offers more precise monitoring of each cell and cell balancing for Li-Ion batteries. This further enhances the performance of the charger when integrated, but is not necessary for charger operation. The battery charger consists of three subcircuits: A microcontroller unit, a power stage, and a current sensing circuit. A C2000 Piccolo F28069 microcontroller controls a LM5117 Buck Controller by injecting a pulse-width modulated signal into the feedback node controlling the output of the buck to set a constant current or constant voltage thus creating a programmable battery charger. The pulse-width modulated signal changes according to charge algorithms created in software for specific battery chemistries and charge requirements. An analog-to-digital converter on the microcontroller monitors battery voltage by using a voltage divider and an INA169 current shunt monitor, which outputs a voltage corresponding to the charge current to another analog-to-digital converter on the microcontroller, monitors the charge current. This allows the charger program to maintain correct and safe charging conditions for each charge mode in addition to measuring output power. Lights on the microcontroller display a real-time status to the user of which portion of the charge profile the charger is in. A solid red light means the charger is in the constant current portion of the charge profile. A blinking red light means the charger is in the constant voltage portion. No red light means the battery charger finished and the battery is currently charged above nominal voltage. The battery charger works with the battery management system in the next section to provide ultimate battery charging and managing capabilities. The battery management system consists of two subcircuits: A microcontroller and a battery monitoring circuit. The MSP430FR5969 microcontroller unit communicates with BQ76PL536 battery management integrated circuits to create a battery management system that monitors data such as cell voltage, pack voltage, pack temperature, state of charge, fault statuses, alert statuses, and a variety of other useful cell parameters. This data displays on a liquid crystal display screen through different menu options. The user scrolls through the menus using a capacitive touch slider on the microcontroller unit and selects a given option using the option select button. A cell balance mode allows the user to check the balance of the cells and allows cell balancing if the cells differ by more than a set threshold.
37

Design of an Integrated Battery Charging System for both Wired and Wireless Charging for Battery Electric and Hybrid Vehicles

Elshaer, Mohamed A. January 2020 (has links)
No description available.
38

STIRLING CONVERTOR CONTROL FOR A LUNAR CONCEPT ROVER

Blaze, Gina January 2007 (has links)
No description available.
39

Soliton Battery Management Station

Ye, Yonglan 24 May 2018 (has links)
No description available.
40

Automatic PMG Controller for Small Applications

Adkins, William Scott January 2015 (has links)
No description available.

Page generated in 0.2591 seconds