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Full-Text Articles in Engineering

Lattice Boltzmann Methods For Wind Energy Analysis, Stephen Lloyd Wood Aug 2016

Lattice Boltzmann Methods For Wind Energy Analysis, Stephen Lloyd Wood

Doctoral Dissertations

An estimate of the United States wind potential conducted in 2011 found that the energy available at an altitude of 80 meters is approximately triple the wind energy available 50 meters above ground. In 2012, 43% of all new electricity generation installed in the U.S. (13.1 GW) came from wind power. The majority of this power, 79%, comes from large utility scale turbines that are being manufactured at unprecedented sizes. Existing wind plants operate with a capacity factor of only approximately 30%. Measurements have shown that the turbulent wake of a turbine persists for many rotor diameters, inducing increased vibration …


Wind Farm Wake Modeling And Analysis Of Wake Impacts In A Wind Farm, Yujia Hao Jul 2016

Wind Farm Wake Modeling And Analysis Of Wake Impacts In A Wind Farm, Yujia Hao

Doctoral Dissertations

More and more wind turbines have been grouped in the same location during the last decades to take the advantage of profitable wind resources and reduced maintenance cost. However wind turbines located in a wind farm are subject to a wind field that is substantially modified compared to the ambient wind field due to wake effects. The wake results in a reduced power production, increased load variation on the waked turbine, and reduced wake farm efficiency. Therefore the wake has long been an important concern for the wind farm installation, maintenance, and control. Thus a wake simulation tool is required. …


Modeling And Control Of A Doubly Fed Induction Generator With A Disturbance Observer: A Stator Voltage Oriented Approach, Eşref Emre Özsoy, Edin Golubovic, Asif Sabanovic, Seta Bogosyan, Meti̇n Gökaşan Jan 2016

Modeling And Control Of A Doubly Fed Induction Generator With A Disturbance Observer: A Stator Voltage Oriented Approach, Eşref Emre Özsoy, Edin Golubovic, Asif Sabanovic, Seta Bogosyan, Meti̇n Gökaşan

Turkish Journal of Electrical Engineering and Computer Sciences

The popularity of renewable energy conversion systems, and especially of wind energy, has been growing in recent years. Doubly fed induction generator (DFIG)-based wind energy systems are extensively used due to their wide range of active and reactive power controllability. Conventional DFIG control structures consist of decoupled PI rotor current controllers with stator flux orientation and machine parameter-dependent compensating terms. The accuracy of stator flux calculations is dependent on how accurately the stator resistance is known. Integration problems also exist and additional low-pass filters are implemented to accurately calculate the stator flux. In the current study, machine-dependent compensating terms are …


Dynamic Characteristics Of An Isolated Self-Excited Synchronous Reluctance Generator Driven By A Wind Turbine, Mosaad Mohiedden Ali, Said Mahmoud Allam, Talaat Hamdan Abdel-Moneim Jan 2016

Dynamic Characteristics Of An Isolated Self-Excited Synchronous Reluctance Generator Driven By A Wind Turbine, Mosaad Mohiedden Ali, Said Mahmoud Allam, Talaat Hamdan Abdel-Moneim

Turkish Journal of Electrical Engineering and Computer Sciences

This paper studies the dynamic characteristics of an isolated three-phase self-excited synchronous reluctance generator (SESRG) driven by a variable-speed wind turbine under different operating conditions. Self-excitation is achieved via capacitors connected across the generator terminals. A detailed mathematical modeling of the proposed self-excited wind generation system is presented. The proposed analysis is based on the dynamic qd-axis model of the SESRG. Magnetic saturation is taken into account and is assumed to be confined to the direct axis and is accounted for as a variable direct-axis magnetizing reactance. Effect of wind-speed variation, excitation-capacitance variation, and loading-conditions variation on the generated output …


Process Time And Mppt Performance Analysis Of Cf, Lut, And Ann Control Methods For A Pmsg-Based Wind Energy Generation System, Abdulhaki̇m Karakaya, Ercüment Karakaş Jan 2016

Process Time And Mppt Performance Analysis Of Cf, Lut, And Ann Control Methods For A Pmsg-Based Wind Energy Generation System, Abdulhaki̇m Karakaya, Ercüment Karakaş

Turkish Journal of Electrical Engineering and Computer Sciences

Due to environmental issues such as global warming and the greenhouse effect, there is a growing interest in renewable sources of energy. Wind energy, which is the most important of these energy sources, can potentially meet a portion of the global energy demand. Numerous studies are being conducted worldwide to determine how the maximum level of power can be obtained from wind energy. In these studies, there is a particular interest in permanent magnet synchronous generators (PMSGs). This is because PMSGs exhibit a good performance within a wide range wind speeds and can be driven directly. In this study, the …


Variations And Relations Of Meteorological Parameters Between Upwind And Downwind Small-Scale Wind Turbine Rotor Area, Ercan İzgi̇, Mustafa Kemal Kaymak, Ahmet Öztopal, Bi̇hter Durna, Ahmet Duran Şahi̇n Jan 2016

Variations And Relations Of Meteorological Parameters Between Upwind And Downwind Small-Scale Wind Turbine Rotor Area, Ercan İzgi̇, Mustafa Kemal Kaymak, Ahmet Öztopal, Bi̇hter Durna, Ahmet Duran Şahi̇n

Turkish Journal of Electrical Engineering and Computer Sciences

Renewable energy sources are becoming increasingly important due to climate change and the energy crisis. Wind energy projects and applications in particular have been growing recently. Meteorological parameters such as wind speed, ambient temperature, relative humidity, and air pressure directly affect wind turbine electricity generation. Understanding the relationships among these parameters is necessary to determine wind energy potential and to predict electricity generation. The current work is based on data obtained from a 1.5 kW wind turbine constructed in İstanbul Technical University's meteorological park in Turkey. A one minute time interval was used in the data analysis. In this study, …