• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 263
  • 61
  • 34
  • 22
  • 12
  • 10
  • 10
  • 9
  • 7
  • 4
  • 4
  • 4
  • 1
  • 1
  • 1
  • Tagged with
  • 520
  • 520
  • 172
  • 151
  • 83
  • 63
  • 63
  • 54
  • 48
  • 48
  • 45
  • 44
  • 41
  • 38
  • 37
  • 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.
101

On the Use of a Digital Communication Channel for Feedback in a Position Control System

Bhattarai, Kripesh January 2012 (has links)
No description available.
102

Acausal Modeling of Wind Turbines with Validation and Control Studies

Mohsin, Kazi Ishtiak 01 January 2023 (has links) (PDF)
This thesis involves the modeling, validation, and control studies of a Control-Oriented, Reconfigurable, and Acausal Floating Turbine Simulator (CRAFTS), that is currently under development. CRAFTS uses Modelica®, an object-oriented, declarative, multi-domain modeling language for physical system modeling in the Dymola environment. The CRAFTS simulator facilitates rapid dynamic simulation of wind turbines with various model variants and enables control co-design. A major emphasis of this thesis is in the validation of the CRAFTS simulator for a 15-MW land-based wind turbine through several test cases. These test cases were collaboratively developed in conjunction with other participating research entities. CRAFTS has undergone rigorous testing, with a particular emphasis on comparison against the industry standard OpenFAST platform (developed by the National Renewable Energy Lab (NREL)) as well as experimental data. Open loop testing scenarios scrutinize the wind turbine dynamic conditions such as varying rotor speed and pitching angle maneuvers. Diverse combinations of ramp and step commands have been employed to modulate rotor speeds and pitching angles. Validation results indicate very good agreement between CRAFTS and baseline results. CRAFTS was also tested under various types of closed-loop control scenarios, such as different types of wind profiles and various wind velocities. Wind types encompass stepped winds, wind gusts, steady winds, and sinusoidal wind patterns. In closed loop testing, firstly an industry standard controller ROSCO (also developed by NREL) was used. Thereafter, a nonlinear controller developed in our prior research was implemented and investigated. The closed loop performance of the CRAFTS model was compared with OpenFAST. The tests confirmed the validity of the CRAFTS model under closed-loop and also validated the nonlinear controller. The work was a critical element in the development of the CRAFTS simulator. Validation tests provided valuable insight into the accuracy of the underlying physics and often provided valuable feedback that led to model improvements. The work has laid the foundations for more advanced research, especially in the area of multivariable control design for floating offshore wind turbines.
103

Blade element approach for computational modeling of lift driven horizontal axis wind turbine performance

Ittycheri, Abraham 25 November 2020 (has links)
The United Nations have declared the effects of climate change as the “defining issue of our time” (United Nations, 2019). As a result of increased industrialization in the last century to keep up with the demands of a growing global population, the global output of greenhouse emissions has rocketed, which is linked to the shifting and abnormal weather patterns of the planet. Electricity and heat production alone are attributed to generating 25% of greenhouse gas emissions (Edenhofer, et al.). To alleviate the increasing levels of carbon emission there is an effort to transition in green energy power generation sources like wind energy that is abundantly available in the midwestern United States. This study aims to implement the Blade Element Method derived modeling methods for predicting the performance of a wind turbine. The experimental results obtained from the MEXICO project is employed as the validation source for the research.
104

A New Technique to Study Temperature Effects on Ice Adhesion Strength for Wind Turbine Materials

Gouni, Rajkiran January 2011 (has links)
No description available.
105

LONGITUDINAL CONTROL OF A NOVEL AIRBORNE WIND ENERGY SYSTEM

Tierno, Nicholas C. 15 June 2011 (has links)
No description available.
106

An Integrated Framework of Performance Assessment and Drivetrain Prognostics for Wind Turbines

Zhao, Wenyu 20 October 2014 (has links)
No description available.
107

WindLCOEA MATLAB TOOL FOR OPTIMIZING THE LEVELIZED COST OF ENERGY FOR WIND TURBINE DESIGNS

Pettit, Erica S. 12 June 2014 (has links)
No description available.
108

A Probabilistic Approach for Prognostics of Complex Rotary Machinery Systems

Zhao, Wenyu 09 June 2015 (has links)
No description available.
109

A Study of the Aerodynamic Behavior of a NREL Phase VI Wind Turbine Using the CFD Methodology

Chen, Yen-Pin 14 September 2011 (has links)
No description available.
110

CHARACTERIZATION OF CUP ANEMOMETER DYNAMICS AND CALCULATION OF THE ACOUSTIC NOISE PRODUCED BY A NREL PHASE VI WIND TURBINE BLADE

Chen, Yng-Ru 31 May 2016 (has links)
No description available.

Page generated in 0.0829 seconds