Increased Power Capture by Rotor Speed–Dependent Yaw Control of Wind Turbines

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Knud A. Kragh ◽  
Paul A. Fleming ◽  
Andrew K. Scholbrock
Keyword(s):  
Wind Turbines ◽  
Rotor Speed ◽  
Wind Speeds ◽  
Yaw Control ◽  
Correction Scheme ◽  
Power Capture ◽  
Horizontal Axis Wind Turbines ◽  
Power Yield ◽  
Additional Costs ◽  
Rotor Axis

When extracting energy from the wind using upwind, horizontal-axis wind turbines, a primary condition for ensuring maximum power yield is the ability to align the rotor axis with the dominating wind direction. Attempts have been made to improve the yaw alignment of wind turbines by applying advanced measurement technologies, such as light detection and ranging systems. However, application of advanced measurement equipment is associated with additional costs and increased system complexity. This study is focused on assessing the current performance of an operating turbine and exploring how the yaw alignment can be improved using measurements from the existing standard measurements system. By analyzing data from a case turbine and a corresponding meteorological mast, a correction scheme for the original yaw control system is suggested. The correction scheme is applied to the case turbine and tested. Results show that, with the correction scheme in place, the yaw alignment of the case turbine is improved and the yaw error is reduced to the vicinity of zero degrees. As a result of the improved yaw alignment, an increased power capture is observed for below-rated wind speeds.

scholarly journals Observation of the Starting and Low Speed Behavior of Small Horizontal Axis Wind Turbine

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Sikandar Khan ◽  
Kamran Shah ◽  
Izhar-Ul-Haq ◽  
Hamid Khan ◽  
Sajid Ali ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Horizontal Axis ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds ◽  
Starting Time ◽  
Speed Range ◽  
Horizontal Axis Wind Turbines ◽  
Starting Torque ◽  
High Angles Of Attack

This paper describes the starting behavior of small horizontal axis wind turbines at high angles of attack and low Reynolds number. The unfavorable relative wind direction during the starting time leads to low starting torque and more idling time. Wind turbine models of sizes less than 5 meters were simulated at wind speed range of 2 m/s to 5 m/s. Wind turbines were modeled in Pro/E and based on the optimized designs given by MATLAB codes. Wind turbine models were simulated in ADAMS for improving the starting behavior. The models with high starting torques and less idling times were selected. The starting behavior was successfully improved and the optimized wind turbine models were able to produce more starting torque even at wind speeds less than 5 m/s.

scholarly journals Modified Design of Savonius Wind Turbine Blade for Performance Improvement

2019 ◽  
Vol 9 (1) ◽  
pp. 1432-1437
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
New Technologies ◽  
Vertical Axis ◽  
Horizontal Axis ◽  
Wind Speeds ◽  
Wind Potential ◽  
Horizontal Axis Wind Turbines ◽  
Savonius Wind Turbine ◽  
Low Performance

In the context of worldwide energetic transition, wind energy shows up as one of the most prominent renewable energy to provide an alternative for the conventional energy source. Therefore, new technologies of a wind turbine are developed, horizontal axis wind turbines have been extensively investigated and evolved. However, the development of vertical axis wind turbines is still an open and area of research, The main objective is to develop a more efficient type of wind turbines able to operate at low wind speeds to take hold maximum wind potential, The Savonius rotor goes with such conditions, however, it faces critical drawbacks, in particular, the low performance in comparison with horizontal axis wind turbines, as well, the blade in return of savonius wind turbine generates a negative torque leading to a decrement of turbine performance. The present work aims to investigate a modified model of the conventional Savonius rotors with a focus on improving the coefficient of power, transient computational fluid dynamics (CFD) simulations are carried out in an effort to perform a validation of numerical results according to experimental data, also to conduct a comparative analysis of both savonius models

Yaw Control of Small Wind Turbines With a New Passive Tail Device: Part 1 — Steady-State Case

Solar Energy ◽  
2003 ◽  
Author(s):  
Eduardo Rinco´n Meji´a ◽  
Jesu´s Tovar Salazar ◽  
Jo´zef Wo´jcik Filipek
Keyword(s):  
Steady State ◽  
Wind Turbine ◽  
Field Test ◽  
Wind Turbines ◽  
Strong Wind ◽  
Test Results ◽  
Yaw Control ◽  
Small Wind Turbines ◽  
Horizontal Axis Wind Turbines ◽  
State Case

This paper describes the behavior of a new tail device to yaw smoothly small wind turbine rotors out of the wind during strong wind or gusts. The passive tail device consists of a rigid short tail, an aerodynamic rotating vane, a tail bumper, and a spring. This passive tail device reduces gyroscopic loads, is easy to adjust, can be manufactured in smaller sizes, and is much stronger than conventional vanes used in small wind machines. Besides, the energy collected with it is greater. Field test results indicate that its behavior agrees very well with simulations, and that the regulator can be advantageously utilized, as compared with conventional vanes and other mechanical or electromechanical means, in horizontal-axis wind turbines with diameters of 12 m or smaller. Here the steady-state case (quasi-steady wind velocity is assumed) is analyzed, showing the technical viability of the regulator proposed.

Potential of Retrofit Passive Flow Control for Small Horizontal Axis Wind Turbines

2016 ◽  
Author(s):  
D. Holst ◽  
G. Pechlivanoglou ◽  
F. Wegner ◽  
C. N. Nayeri ◽  
C. O. Paschereit
Keyword(s):  
Flow Control ◽  
Wind Turbines ◽  
High Performance ◽  
Horizontal Axis ◽  
Vortex Generators ◽  
Passive Flow Control ◽  
Wind Speeds ◽  
Passive Flow ◽  
Horizontal Axis Wind Turbines ◽  
Low Reynolds

The present paper analyzes the effect of passive flow control (PFC) with respect to the retrofitting on small horizontal axis wind turbines (sHAWT). We conducted extensive wind tunnel studies on an high performance low Reynolds airfoil using different PFC elements, i.e. vortex generators (VGs) and Gurney flaps. QBlade, an open source Blade Element Momentum (BEM) code, is used to study the retrofitting potential of a simulated small wind turbine. The turbine design is presented and discussed. The simulations include the data and polars gained from the experiments and give further insight into the effects of PFC on sHAWT. Therefore several different blades were simulated using several variations of VG positions. This paper discusses their influence on the turbine performance. The authors focus especially on the start-up performance as well as achieving increased power output at lower wind speeds. The vortex generators reduce the risk of laminar separation and enhance the lift in some configurations by more than 40% at low Reynolds numbers.

Analytical and experimental study of the integral aerodynamic characteristics of low-speed wind turbines

2014 ◽  
Vol 118 (1209) ◽  
pp. 1229-1244 ◽  
Author(s):  
M. Valiev ◽  
R. Stepanov ◽  
V. Pakhov ◽  
M. Salakhov ◽  
V. Zherekhov ◽  
...  
Keyword(s):  
Wind Turbines ◽  
Power Efficiency ◽  
Wind Farm ◽  
Aerodynamic Characteristics ◽  
Optimal Conditions ◽  
Low Speed ◽  
Wind Speeds ◽  
Horizontal Axis Wind Turbines ◽  
Low Wind Speeds ◽  
Theoretical Results

Abstract This paper proposes a new wind turbine concept suitable for low-speed winds. The design is studied using a combination of wind-tunnel experimentation and aerodynamic theory. After processing the experimental results, and after comparison with theory, the optimal conditions for the operation of the turbine are identified. Experimental and theoretical results suggest that the design offers a realistic alternative to conventional horizontal axis wind turbines. In addition, the proposed turbine has good power efficiency at low wind speeds, and is suitable for deployment in areas not yet favoured by wind farm developers.

scholarly journals Efficiency comparison of horizontal axis wind turbines and bladeless turbines

2017 ◽  
Vol 4 ◽  
pp. 59-75 ◽  
Author(s):  
Antranig Tony Bardakjian ◽  
Paul Pavlos Mandadakis ◽  
Amy Tingle
Keyword(s):  
Wind Turbines ◽  
Power Output ◽  
Horizontal Axis ◽  
Research Needs ◽  
Research Papers ◽  
Wind Speeds ◽  
Horizontal Axis Wind Turbines ◽  
Efficiency Comparison ◽  
Cost Efficient

The purpose of this meta study is to determine whether bladeless wind turbines are more efficient than horizontal axis wind turbines. Using resources such as research papers, online articles and academic papers from different academic databases provided by UTS library, a comparison between these wind turbines was constructed. Using Weibull’s equation, it was found that horizontal axis wind turbines are still more efficient. Although bladeless are more cost efficient, offshore horizontal axis wind turbines produce more energy at lower wind speeds, due to the ratio between power usage to power output of approximately 80% for bladed turbines and approximately 70% for bladeless turbines. More research needs to be done on how to increase the efficiency of these wind turbines.

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