Recent Advances in Small Wind Turbine Technology

2000 ◽  
Vol 24 (3) ◽  
pp. 189-201 ◽  
Author(s):  
P. D. Clausen ◽  
D. H. Wood
Keyword(s):  
Wind Turbine ◽  
Fatigue Testing ◽  
Low Wind Speed ◽  
Recent Advances ◽  
Starting Point ◽  
Recent Developments ◽  
Speed Performance ◽  
Power Limit ◽  
Turbine Design ◽  
Large Wind

This paper reviews some recent advances in the technology of small wind turbines, whose upper power limit we take arbitrarily as 50 kW. Small turbines are used mainly for remote power generation either alone or in conjunction with other energy sources and battery storage. They can be divided into three categories: micro, up to 1 kW; mid-range; and mini-turbines, of 20 kW and larger, intended mainly for wind/diesel mini-grids. The paper discusses a number of issues that are category-dependent; for example, low-wind-speed performance is most critical for microturbines. The starting point for the review is the mature level of large wind turbine technology, and it is demonstrated that this maturity has yet to percolate downwards. Nevertheless, there have been a number of very encouraging recent developments. These include improvements to our understanding of the basic aerodynamics and advances in blade manufacturing, the use of micro-processor controls, and the increasing use of design certification and type approval. The developments are highlighted by two case studies of small turbine design in which the authors were involved. We conclude with a brief discussion of current developments in technology, such as fatigue testing of blades and new methods of blade design, which should further increase the level of small turbine technology towards that of large machines.

Evaluation of dual-axis fatigue testing of large wind turbine blades

2011 ◽  
Vol 226 (7) ◽  
pp. 1693-1704 ◽  
Author(s):  
Peter R Greaves ◽  
Robert G Dominy ◽  
Grant L Ingram ◽  
Hui Long ◽  
Richard Court
Keyword(s):  
Service Life ◽  
Wind Turbine ◽  
Fatigue Testing ◽  
Turbine Blades ◽  
Bending Moment ◽  
Fatigue Tests ◽  
Simulation Software ◽  
Wind Turbine Blades ◽  
Moment Distribution ◽  
Large Wind

Full-scale fatigue testing is part of the certification process for large wind turbine blades. That testing is usually performed about the flapwise and edgewise axes independently but a new method for resonant fatigue testing has been developed in which the flapwise and edgewise directions are tested simultaneously, thus also allowing the interactions between the two mutually perpendicular loads to be investigated. The method has been evaluated by comparing the Palmgren–Miner damage sum around the cross-section at selected points along the blade length that results from a simulated service life, as specified in the design standards, and testing. Bending moments at each point were generated using wind turbine simulation software and the test loads were designed to cause the same amount of damage as the true service life. The mode shape of the blade was tuned by optimising the position of the excitation equipment, so that the bending moment distribution was as close as possible to the target loads. The loads were converted to strain–time histories using strength of materials approach, and fatigue analysis was performed. The results show that if the bending moment distribution is correct along the length of the blade, then dual-axis resonant testing tests the blade much more thoroughly than sequential tests in the flapwise and edgewise directions. This approach is shown to be more representative of the loading seen in service and can thus contribute to a potential reduction in the weight of wind turbine blades and the duration of fatigue tests leading to reduced cost.

Design comparison of wind turbines for low wind speed

2019 ◽  
Vol 2 (3) ◽  
pp. 222-229
Author(s):  
Dena Hendriana ◽  
Eka Budiarto ◽  
Alexander Clements ◽  
Arko Djajadi
Keyword(s):  
Computer Simulation ◽  
Wind Speed ◽  
Wind Turbine ◽  
Simulation Software ◽  
The Other ◽  
Horizontal Axis Wind Turbine ◽  
Low Wind Speed ◽  
Wind Characteristic ◽  
Turbine Design ◽  
Very High

Wind energy is one of the potential renewable energy, but the applications have to beadjusted to the available wind characteristic in the area. In Indonesia, the wind speed is inaverage not very high, only around 4 m/s. Therefore the wind turbine design have to be adjustedfor usage in Indonesia. In this research, two wind turbine designs are compared. One design isof the form Horizontal-Axis Wind Turbine (HAWT) and the other is of the form Vertical-AxisWind Turbine (VAWT). Both designs are optimized for wind speed of 4 m/s. The comparisonsare done using computer simulation software OpenFOAM. The result shows VAWT design canproduce similar power with smaller turbine dimension than the HAWT design.

The Research of Model-Free Adaptive Control for Large Scale Wind Turbine

2013 ◽  
Vol 433-435 ◽  
pp. 1293-1297
Author(s):  
Xing Jia Yao ◽  
Jiang Sheng Zhu ◽  
Kui Chao Ma ◽  
Qing Ding Guo
Keyword(s):  
Wind Turbine ◽  
Control Strategy ◽  
Large Scale ◽  
External Disturbances ◽  
Pitch Control ◽  
Model Free ◽  
Variable Speed Wind Turbine ◽  
Turbine Design ◽  
Individual Pitch Control ◽  
Large Wind

Dynamic load is a key consideration in large scale wind turbine design. It is approved that the performance of controller can distinguish impact wind turbine loads. For strong external disturbances and inaccurately modeled of large wind turbines, In this paper, we propose model-free adaptive (Model Free Adapt, MFA) individual pitch control algorithms. The controller was developed in to mitigate the rotor unbalance structural load for variable speed wind turbine. The controller is designed from a nonlinear model of the system which takes into account the blades, shaft and tower flexibilities. Bladed software was used for the control strategy and traditional PID control strategy simulation comparison. The results show that the new control strategy can effectively stabilize wind turbine power output and reduce aerodynamic loads.

Modal Analysis of Three Rotating Blades of Large Wind Turbine

2012 ◽  
Vol 157-158 ◽  
pp. 697-701 ◽  
Author(s):  
Guo Yu Hu ◽  
Wen Lei Sun ◽  
An Wu ◽  
Yan Xu
Keyword(s):  
Wind Turbine ◽  
Simulation Analysis ◽  
Coupling Effect ◽  
Simulation Method ◽  
Turbine Rotor ◽  
Rotating Blade ◽  
Simulation Results ◽  
Turbine Design ◽  
Multi Body ◽  
Large Wind

Abstract: Based on the Multi-body dynamics, the dynamics equation of the flexible blade in wind turbine is established by discretizing the rotating blade using finite element method. The simulation analysis of the single blade and the vibration modes of a 5MW wind turbine rotor are carried out by MATLAB. The first six natural frequencies and modes of the single blade and the rotor are figured out, and whose results are analyzed. The simulation results indicates that the coupling effect of the rotor can lead to dynamic stiffening. In comparison to the results in FAST, these simulation results show an outstanding agreement with the results calculated by FAST and hence approve the simulation method is valid and meanwhile give reference for large wind turbine design and running.

Alternate Wind Turbine Blade Planform Design Studies for Low Wind Speeds

2015 ◽  
Author(s):  
Rajesh Kumar V. Gadamsetty ◽  
Jaikumar Loganathan ◽  
Vasanth Kumar Balaramudu ◽  
Ajay Rao
Keyword(s):  
Wind Turbine ◽  
Design Methodology ◽  
Design Method ◽  
Energy Yield ◽  
Wind Speeds ◽  
Low Wind Speed ◽  
Performance Trends ◽  
Low Wind Speeds ◽  
Wind Regimes ◽  
Turbine Design

Wind turbine design for low wind regimes is gaining importance as existing high wind sites are heavily utilized. Maximizing energy yield from a low wind regime while adhering to load constraints is the biggest challenge. Longer rotors and higher towers are currently being used to maximize energy capture and improve AEP. The focus of this work is to assess new blade planforms for low wind speed blade design. Planforms with maple shape are studied and a new design methodology based on lift force distribution is adopted. CFD analysis is carried out for the blade planforms to validate the design methodology and the results show similar performance trends as that of the conventional design method.

New Work on Speech Acts

2018 ◽  
Keyword(s):  
Speech Acts ◽  
Speech Act ◽  
Speech Act Theory ◽  
New Work ◽  
Half Century ◽  
Recent Advances ◽  
Current Thinking ◽  
Semantics And Pragmatics ◽  
Recent Developments ◽  
The Relationship

The essays collected in this book represent recent advances in our understanding of speech acts-actions like asserting, asking, and commanding that speakers perform when producing an utterance. The study of speech acts spans disciplines, and embraces both the theoretical and scientific concerns proper to linguistics and philosophy as well as the normative questions that speech acts raise for our politics, our societies, and our ethical lives generally. It is the goal of this book to reflect the diversity of current thinking on speech acts as well as to bring these conversations together, so that they may better inform one another. Topics explored in this book include the relationship between sentence grammar and speech act potential; the fate of traditional frameworks in speech act theory, such as the content-force distinction and the taxonomy of speech acts; and the ways in which speech act theory can illuminate the dynamics of hostile and harmful speech. The book takes stock of well over a half century of thinking about speech acts, bringing this classicwork in linewith recent developments in semantics and pragmatics, and pointing the way forward to further debate and research.

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