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 133 for “"Variable Speed"”.
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Modeling And Control of Variable Speed Wind Turbines
… past decades. Among the wind turbine systems, Variable speed wind turbines are the most preferred one since it is cheaper, more efficient and has more of control capabilities over the produced active and reactive power. This thesis is prepared in order to contribute to the better understanding …
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Performance and Evaluation of a Variable-Speed Darrieus Wind Turbine
… and building heating) are uniquely suited to the variable power produced by the winds because many agricultural tasks can effectively use variable rates of energy supply. Many agricultural tasks can tolerate short energy interruptions and are easily adapted to inexpensive storage (Hunt, 1981).<br> …
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A field-modulated, variable-speed to constant-frequency power converter
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981.
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The impact of variable speed drives on energy efficient induction motors
… incentives to its industrial customers to speed up this process.
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Design and implementation of a grid-connected variable-speed PM WECS
As renewable energy (RE) sources are increasingly becoming an integral part of the world's power generation capacity, they are becoming more sophisticated and provide a solid platform for power generation today. Wind Energy is the fastest growing RE source. The correct understanding of issues …
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Induction motor variable speed drive performance and impact on energy savings
… under or overvoltages on induction machines (1M) variable speed drives. In addition the performance with PWM inverters connected to 1M via long cables is also studied. The project starts by an evaluation of previous work on the subject and related topics. Relevant conclusions are made based on the …
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A single three phase variable speed drive with unity power factor
… new proposed topology for a single three-phase variable speed drive was developed after considering the advantages and disadvantages of previous topologies. The new topology employs only six switches that form and active front-end rectifier and a four-switch inverter. The active front-end …
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Effects of Input Power Factor Correction on Variable Speed Drive Systems
The use of variable speed drive (VSD) systems in the appliance industry is growing due to emerging high volume of fractional horsepower VSD applications. Almost all of the appliance VSDs have no input power factor correction (PFC) circuits. This results in harmonic pollution of the utility supply …
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A DSP based variable-speed induction motor drive for a revolving stage
Variable speed drive technology has advanced dramatically in the last 10 years with the advent of new power devices. In this study, a three phase induction motor drive using Insulated Gate Bipolar Transistors (IGBT) at the inverter power stage is introduced to implement speed and position control …
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Variable-Speed Switched Reluctance Motor Drives for Low-Cost, High-Volume Applications
Demand for energy-saving variable speed drives in low-cost, high-volume appliances has increased due to energy and environmental concerns and hence the need to comply with new regulations. Switched reluctance motor (SRMs) have been considered by many as attractive alternatives for brush commutated …
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Novel Multilevel Converter for Variable-Speed Medium Voltage Switched Reluctance Motor Drives
… converter that is especially suited for high speed multi-megawatt switched reluctance motor drives operating at the medium voltage level is presented. The drive is capable of variable speed, four-quadrant operation. Each phase leg of the converter contains an arbitrary number of cascaded cells …
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Structural and thermal design of a dual-rotor constant-frequency, variable-speed generator
… to efficiently, reliably and cheaply convert a variable shaft-speed input into a constant electrical frequency output for application in the field of wind power. A optimization of the electrical characteristics has been performed and used as constraints on the mechanical design. Structural and …
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Analysis Of A Dual Scissored-Pair,variable-Speed, Control Moment Gyroscope Driven Spherical Robot
<p>The objective of this research is to compare barycenter offset based designs of spherical robots to control moment gyroscope (CMG) based designs in order to determine which approach is most effective. The first objective was to develop a list of current state of the art designs in order to gain …
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Design and implementation of variable speed wind energy induction generator systems for fault studies
… modeling and implementation of two different variable speed induction generator systems for studying faults in wind energy applications. This project served as a platform for further research into the development and evaluation of a non-stationary fault detection technique suitable for wind …
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Variable speed constant frequency power conversion with permanent magnet synchronous and switched reluctance generators
… is inevitably concerned with the processing of variable speed power generations such as in wind turbines, aircraft systems and naval on-board ship systems. The nature of these types of energy is distinct in that their frequency and power vary depending on the speed of the prime-mover. To make …
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Mathematical Modelling of Grid Connected Fixed- Pitch Variable-Speed Permanent Magnet Synchronous Generators for Wind Turbines
… (PMSG), which is designed for a fixed-pitch variable-speed wind turbine, and its corresponding simulation model for the control of the PMSG for grid connection using MATLAB/Simulink. The model includes sub-modules, such as a model of the wind speed, a model of the PMSG, a model of the …
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Heat pump simulation model and optimal variable-speed control for a wide range of cooling conditions
… map. The map defines the optimal evaporator fan speed, condenser fan speed and compressor speed needed to achieve the lowest total power consumption for the given cooling rate, ambient and zone temperature.
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Modeling Microscopic Driver Behavior under Variable Speed Limits: A Driving Simulator and Integrated MATLAB-VISSIM Study
Variable speed limits (VSL) are dynamic traffic management systems designed to increase the efficiency and safety of highways. While the macroscopic performance of VSL systems is well explored in the existing literature, there is a need to further understand the microscopic behavior of vehicles …
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