Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 131 for “"AC/DC"”.
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MANAGEMENT OF HYBRID (AC-DC) MICRO-GRIDS
… autonomous island mode. We assume that we have DC power sources such as a photovoltaic array and wind turbine in the DC sub-grid that is tied to the AC sub-grid consisting of two uninterruptible power sources (UPS) through a bi-directional single phase inverter. Demand-droop control is used to …
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Adaptive optimal control of AC/DC systems
… a new control strategy for two terminal HVDC systems embedded in an AC network. The control is based upon real-time measurements performed on the AC/DC system. Use is made of a technique for high speed accurate measurement of positive sequence voltages and currents, first developed in the …
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Bi-Directional AC-DC Converters for Electric Vehicles
… Nowadays transportation sectors are replacing their conventional internal combustion vehicles by Electric Vehicles (EVs). Much research efforts have been devoted to improve EVs and EV infrastructure. EV battery and thus the on-board EV battery charger are among the most important parts of …
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Stacked-Switched Electrolytic Capacitor-less AC/DC Power Converters
… Vehicles (EVs) has increased the demand for compact, efficient, and reliable On-Board Chargers (OBCs) capable of interfacing directly with the AC grid. Conventional single-phase AC/DC converters often depend on bulky electrolytic capacitors, diode bridges, and hard-switching circuits, leading to …
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Optimal Design and Planning of Hybrid AC/DC Microgrid
<p>The traditional approach for microgrid design and deployment has been mainly focused on AC systems. DC microgrids, however, are gaining attention due to numerous advantages they provide over AC microgrids, such as removing the need for synchronization and frequency adjustment as well as …
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A single stage power factor corrected AC/DC converter
Applications for AC/DC converters that require high input power factor has been traditionally implemented by two power stages. In order to provide a cost effective and high density solution for low power applications, this thesis proposes a single stage isolated converter topology designed to …
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Miniaturization of Ac-Dc power converters for grid interface
In this thesis we present a two-stage ac/dc grid-connected converter for computer applications. Also known as off-line power supplies, these converters have to meet various demanding specifications such as a wide input voltage range (typically 0-376 V), large voltage step down (typical output …
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Power Management and Control Strategies in Hybrid AC/DC Microgrids
… for customers with lower emissions. Conventional AC or DC microgrid suffers from increased losses and lower efficiency due to several AC-DC and DC-AC conversions. Therefore, hybrid microgrid (HMG) is getting popular to meet the growing penetration of modern DC loads and renewable energy sources …
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Flujo de cargas unificado (AC/DC) aplicado a redes ferroviarias
La utilización de la energía capaz de ser regenerada por los trenes eléctricos constituye uno de los desarrollos más prometedores en el campo del ahorro energético en los sistemas de transporte. Tanto para el estudio del comportamiento eléctrico de dichas redes y evaluación de los distintos …
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A novel backup protection scheme for hybrid AC/DC power systems
… protection scheme designed to safeguard hybrid AC/DC distribution networks against DC faults that are not cleared by the main MVDC (Medium Voltage DC) link protection. The protection scheme relies on the apparent impedance measured at the AC "side" of the MVDC link to detect faults on the DC …
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AC/DC power system small-signal impedance measurement for stability analysis
<p>"Considerable research work has shown that a dc power system is small-signal stable if the Nyquist contour of product of the source impedance and load admittance satisfied the Nyquist stability criterion. Methods of extracting impedance in dc systems have been well established. However, for ac …
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A single stage full bridge power factor corrected AC/DC converter
Conventional single phase AC/DC converters use a two stage power configuration to provide a regulated DC power supply at high input power factor. Elimination of one of these stages can reduce the cost, weight, size, complexity and increase the overall reliability of this converter. This thesis …
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An integrated generator-rectifier system for high-power AC-DC conversion
High power ac-dc conversion plays an increasingly important role in energy conversion systems, such as wind turbines or electric ship grids. Conventional conversion architectures rely heavily on active rectifiers, which consist of fully-controlled power-electronics switches. These make the system …
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Ac-dc Bus-interface Bi-directional Converters in Renewable Energy Systems
… covers several issues related to the ac-dc bus-interface bi-directional converters in renewable energy systems. The dissertation explores a dc-electronic distribution system for residential and commercial applications with a focus on the design of an ac-dc bi-directional converter for …
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A Three-Phase Single-Stage AC-DC ZVZCS PWM Full-Bridge Converter
It is standard practice to use two separate power converters to convert an ac input voltage to a desired and isolated dc output voltage. A front-end ac-dc converter is used to convert the input ac voltage into an intermediate dc voltage which is then fed into a dc-dc converter with transformer …
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A Three-Phase Single-Stage AC-DC ZVZCS PWM Full-Bridge Converter
It is standard practice to use two separate power converters to convert an ac input voltage to a desired and isolated dc output voltage. A front-end ac-dc converter is used to convert the input ac voltage into an intermediate dc voltage which is then fed into a dc-dc converter with transformer …
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Coordinated control of distributed resources in hybrid AC/DC mesh distribution networks
… tiene una dependencia reducida de las comunicaciones en términos de estabilidad, a pesar de que se utilizan para una operación óptima. Se propone un control secundario para el control primario basado en droop, caracterizado por su flexibilidad y robustez frente a retrasos en la comunicación o …
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Quantifying the performance of the Kim AC/DC Hybrid Power Flow Model
… Hybrid Power Flow Model, looking to quantify its accuracy as compared to the two most common steady-state power flow modeling techniques. For the analysis, a 37-bus system was selected as the common modeling platform in order to facilitate like-for-like comparisons. With an emphasis on minimizing …
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A fast analog controller for a unity power factor AC/DC converter
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1993.
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High-Frequency Quasi-Single-Stage (QSS) Isolated AC-DC and DC-AC Power Conversion
… (QSS) power conversion topology for ac-dc rectification and dc-ac inversion is proposed. The topology is reached by direct cascading and synchronized switching of two variety of buck or two variety of boost switching networks. The family of QSS power converters feature single-stage …
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