Dynamic Optimization of Drivetrain Gear Ratio to Maximize Wind Turbine Power Generation—Part 1: System Model and Control Framework

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
John F. Hall ◽  
Dongmei Chen
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Dynamic Optimization ◽  
Low Cost ◽  
Gear Ratio ◽  
Normal Operation ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Electric Generator ◽  
Disk Brake

Wind is considered to be one of the most promising resources in the renewable energy portfolio. Still, to make wind energy conversion more economically viable, it is necessary to extract greater power from the wind while minimizing the cost associated with the technology. This is particularly important for small wind turbines, which have the highest cost per kilowatt of energy produced. One solution would be a variable ratio gearbox (VRG) that can be integrated into the simple and low-cost fixed-speed induction generator. Through discrete variable rotor speed operation, the VRG-enabled system affects the wind speed ratio, the power coefficient, and ultimately the power produced. To maximize electrical production, mechanical braking is applied during the normal operation of the wind turbine. A strategy is used to select gear ratios (GRs) that produce torque slightly above the maximum amount the generator can accept while simultaneously applying the mechanical brake, so that full load production may be realized over greater ranges of the wind speed. To characterize the performance of the system, a 100 kW, fixed speed, stall-regulated wind turbine, has been developed for this study. The VRG-enabled wind turbine control system is presented in two papers. Part 1 focuses on the turbine simulation model, which includes the rotor, VRG-enabled drivetrain, disk brake, and electric generator. A technique for estimating the performance of a disk brake, in the wind turbine context, is also presented. Part 2 of the research will present a dynamic optimization algorithm that is used to establish the control protocol for competing performance objectives.

Experimental Study of Vertical Axis Wind Turbine with Wind Speed Self-Adapting

2012 ◽  
Vol 215-216 ◽  
pp. 1323-1326
Author(s):  
Ming Wei Xu ◽  
Jian Jun Qu ◽  
Han Zhang
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Velocity ◽  
Vertical Axis ◽  
Maximum Power ◽  
The Self ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Opening And Closing

A small vertical axis wind turbine with wind speed self-adapting was designed. The diameter and height of the turbine were both 0.7m. It featured that the blades were composed of movable and fixed blades, and the opening and closing of the movable blades realized the wind speed self-adapting. Aerodynamic performance of this new kind turbine was tested in a simple wind tunnel. Then the self-starting and power coefficient of the turbine were studied. The turbine with load could reliably self-start and operate stably even when the wind velocity was only 3.6 m/s. When the wind velocity was 8 m/s and the load torque was 0.1Nm, the movable blades no longer opened and the wind turbine realized the conversion from drag mode to lift mode. With the increase of wind speed, the maximum power coefficient of the turbine also improves gradually. Under 8 m/s wind speed, the maximum power coefficient of the turbine reaches to 12.26%. The experimental results showed that the new turbine not only improved the self-starting ability of the lift-style turbine, but also had a higher power coefficient in low tip speed ratio.

scholarly journals STUDI EKSPERIMENTAL PERFORMANSI TURBIN SAVONIUS DI PESISIR PANTAI KABUPATEN DEMAK TERHADAP DAYA LISTRIK YANG DIHASILKAN

2021 ◽  
Vol 14 (1) ◽  
pp. 16
Author(s):  
Wahyu Santoso ◽  
Herman Saputro ◽  
Husin Bugis
Keyword(s):  
Renewable Energy ◽  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Raw Material ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Generator Type ◽  
Wind Potential ◽  
Savonius Wind Turbine

<p><em>Energy from fossil fuels consisting of petroleum, coal, natural gas containing raw material for energy fulfillment in Indonesia is still very central through the use of raw materials from renewable energy is still very low. In Indonesia the potential for renewable energy such as wind energy needs to be optimized. One of the uses of wind energy is through savonius wind turbine as electricity generators. Characteristics of savonius wind turbine with vertical axis rotors which gave a simple shape, and that able to control low speeds. This is in accordance with regions in Indonesi which have low average speeds.         This experimental study, aims to determine the description of wind potential and determine the performance of savonius wind turbines on the coast of Demak regency on the electrical energy produced. Savonius wind turbine used is made of galvalum material in the form of an S type rotor with diameter 1.1 m and height 1.4 m, using pulley transmission system with multiplication ratio 1:6 dan using generator type PMG 200 W. This research uses the method experiment. Data collection in the form of wind speed, humidity, temperature, rotor rotation speed, voltage and electric curret is carried out at 14.30 to 17.30 Western Indonesian Time. Data Analysis in this study uses quantitative descriptive analysis. The result showed the potential of wind on the coast of Demak regency have an average wind speed of 2,02 m/s with a temperature of 31</em><em>,</em><em>34 </em><em><sup>0</sup></em><em>C and humidity of 76,96. And the performance of the installed wind turbine produces the highest power 3.5 watt with an electric power coefficient of 0,181 and tip speed ratio around 1,75. From these result, the potensial of wind with performance savonius turbine can generate electricity used for pond lighting in the village Berahan Kulon Kecamatan Wedung. </em><em></em></p>

Aerodynamic Design and Analysis of a Flanged Diffuser Augmented Wind Turbine

2013 ◽  
Author(s):  
A. Tourlidakis ◽  
K. Vafiadis ◽  
V. Andrianopoulos ◽  
I. Kalogeropoulos
Keyword(s):  
Wind Speed ◽  
Flow Field ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Research Work ◽  
Flow Analysis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Computational Domain ◽  
Aerodynamic Design

Many researchers proposed methods for improving the efficiency of small Horizontal Axis Wind Turbines (HAWTs). One of the methods developed to increase the efficiency of HAWTs and to overcome the theoretical Betz limit is the introduction of a converging – diverging casing around the turbine. To further improve the performance of the diffuser a flange is placed at its outlet, which smoothes the flow along the diffuser interior, allowing larger diffusion angles to be utilized. The purpose of this research work is the aerodynamic design and computational analysis of such an arrangement with the use of Computational Fluid Dynamics (CFD). First, a HAWT rotor rotating at 600 RPM was designed with the use of the Blade Element Momentum (BEM) method. The three rotor blades are constructed using the NREL airfoil sections family S833, S834 and S835. The power coefficient of the rotor was optimised in a wind speed range of 5 – 10 m/s, with a maximum value of 0.45 for a wind speed of 7m/s. A full three-dimensional CFD analysis was carried out for the modeling of the flow around the rotor and through the flanged diffuser. The computational domain consisted of two regions with different frames of reference (a stationary and a rotating). The rotating frame rotates at 600 RPM and includes the rotor with the blades. All the simulations were performed using the commercial CFD software package ANSYS CFX. The Shear Stress Transport turbulence model was used for the simulations. Detailed flow analysis results are presented, dealing with the various investigated test cases, a) isolated turbine rotor, b) diffuser without the presence of the turbine, and c) the full turbine – diffuser arrangement for different flange heights and wind speeds. By varying the height of the flange and the wind speed, the effects of the above on the flow field and the power coefficient of the turbine were studied. The CFD resulting power coefficients are also compared and good agreement with existing in the literature experimental data was obtained. The results showed that there is a significant improvement in the performance of the wind turbine (by a factor from 2 to 5 on power coefficient at high blade tip speed ratio) and the proposed modification is particularly attractive for small wind turbines. The particular characteristics of the flow field, that are responsible for this improvement are identified and analysed in detail offering a better understanding of the physical processes involved.

scholarly journals Small Wind Turbine Blade Design and Optimization

Symmetry ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 18 ◽  
Author(s):  
Hani Muhsen ◽  
Wael Al-Kouz ◽  
Waqar Khan
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Optimization Process ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Horizontal Axis Wind Turbine ◽  
Design And Optimization ◽  
Low Wind Speed ◽  
Low Performance ◽  
Turbine Blade Design

This work aims at designing and optimizing the performance of a small Horizontal-Axis-Wind-Turbine to obtain a power coefficient (CP) higher than 40% at a low wind speed of 5 m/s. Two symmetric in shape airfoils were used to get the final optimized airfoil. The main objective is to optimize the blade parameters that influence the design of the blade since the small turbines are prone to show low performance due to the low Reynolds number as a result of the small size of the rotor and the low wind speed. Therefore, the optimization process will select different airfoils and extract their performance at the design conditions to find the best sections which form the optimal design of the blade. The sections of the blade in the final version mainly consist of two different sections belong to S1210 and S1223 airfoils. The optimization process goes further by investigating the performance of the final design, and it employs the blade element momentum theory to enhance the design. Finally, the rotor-design was obtained, which consists of three blades with a diameter of 4 m, a hub of 20 cm radius, a tip-speed ratio of 6.5 and can obtain about 650 W with a Power coefficient of 0.445 at a wind-speed of 5.5 m/s, reaching a power of 1.18 kW and a power coefficient of 0.40 at a wind-speed of 7 m/s.

Aerodynamic Performance Analysis of a Large Scale Wind Turbine Blade under Variable Condition

2013 ◽  
Vol 291-294 ◽  
pp. 527-530
Author(s):  
Peng Zhan Zhou ◽  
Fang Sheng Tan
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Power ◽  
Turbine Blade ◽  
Large Scale ◽  
Aerodynamic Performance ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
Variable Condition

Based on BLADED software, the aerodynamic performance of a large scale wind turbine blade was analyzed under variable condition. The results show that the rated power of the blade under variable condition is increased 10%, when the rated wind speed is changed from 10.5m/s to 11.0 m/s. The blade’s wind power coefficient is above 0.46, and its tip speed ratio is between 7.8 and 11.4. When its tip speed ratio is 9.5, the blade’s maximum wind power coefficient is 0.486. It is indicated that the blade has good aerodynamic performance and wide scope of wind speed adaptive capacity. The blade root’s equivalent fatigue load is 2.11 MN•m, and its extreme flapwise load is 4.61 MN•m. The loads under variable condition are both less than that of the designed condition, so the blade’s application under variable condition is safe.

scholarly journals Assessment of the apparent performance characterization along with levelized cost of energy of wind power plants considering real data

2018 ◽  
Vol 36 (6) ◽  
pp. 1708-1728 ◽  
Author(s):  
Zahid H Hulio ◽  
Wei Jiang
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Power ◽  
Power Plants ◽  
Wind Farm ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Data Set ◽  
Levelized Cost ◽  
Cost Of Energy

Pakistan pursued the renewable energy policy to minimize the cost of energy per kWh as well as dependence on costly imported oil. Jhimpir site is termed as wind corridor and has tremendous proven wind power potential. The site is hosted for the first installed wind power plant. The aim of paper is to investigate the performance and levelized cost of energy of a wind farm. The methodology covers assessment of wind characteristics, performance function and levelized cost of energy model. The measured mean wind speed was found to be 8 m/s at 80 m above the ground level. The average values of standard deviation, Weibull k and c parameters, obtained using entire data set, were found to be 2.563, 3.360 and 8.940 m/s at 80 m. Performance assessment including technical, real availability and average capacity factor was found to be 97, 90 and 34.50%, respectively. It is evident that the power coefficient dropped if wind speed crosses the rated power. So it can be concluded that the efficiency of wind turbine decreased by increased wind speed. Tip speed ratio shows that a wind turbine operating close to optimal lift and drag will exhibit the performance level. Wind turbine performs better at the wind speed between 6 and 10 m/s. The estimated average levelized cost of energy was US $0.11371 and US $0.04092/kWh for 1–10 and 11–20 years, respectively. This makes it competitive in terms of low production cost per kWh to other energy technologies.

A Numerical Study on the Effects of Unsteady Wind on Vertical Axis Wind Turbine Performance

2013 ◽  
Author(s):  
Louis Angelo Danao ◽  
Jonathan Edwards ◽  
Okeoghene Eboibi ◽  
Robert Howell
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Numerical Study ◽  
Angle Of Attack ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Peak Performance ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio

Numerical simulations using RANS–based CFD have been utilised to carry out investigations on the effects of unsteady wind in the performance of a wind tunnel vertical axis wind turbine. Using a validated CFD model, unsteady wind simulations revealed a fundamental relationship between instantaneous VAWT CP and wind speed. CFD data shows a CP variation in unsteady wind that cuts across the steady CP curve as wind speed fluctuates. A reference case with mean wind speed of 7m/s, wind speed amplitude of ±12%, fluctuating frequency of 0.5Hz and mean tip speed ratio of 4.4 has shown a wind cycle mean power coefficient of 0.33 that equals the steady wind maximum. Increasing wind speed causes the instantaneous tip speed ratio to fall which leads to higher effective angle of attack and deeper stalling on the blades. Stalled flow and rapid changes in angle of attack of the blade induce hysteresis loops in both lift and drag. Decreasing wind speeds limit the perceived angle of attack seen by the blades to near static stall thus reducing the positive effect of dynamic stall on lift generation. Three mean tip speed ratio cases were tested to study the effects of varying conditions of VAWT operation on the overall performance. As the mean tip speed ratio increases, the peak performance also increases.

Aerodynamic Design Optimization of Elliptical-Bladed Savonius-Style Wind Turbine by Numerical Simulations

2016 ◽  
Author(s):  
Nur Alom ◽  
Satish Chandra Kolaparthi ◽  
Sarath Chandra Gadde ◽  
Ujjwal K. Saha
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
Wind Turbine ◽  
Numerical Study ◽  
Low Cost ◽  
Vertical Axis ◽  
3D Simulation ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine

Savonius-style wind turbine (SSWT), a class of vertical-axis wind turbine, appears to be promising for off-shore applications because of its design simplicity, good starting ability, insensitivity to wind direction, relatively low operating speed, low cost and easy installation. Various blade shapes have been used over the years to improve the performance of this class of turbine. In the recent past, an elliptic-bladed profile with sectional cut angle of 50° has shown its potential to harness the wind energy more efficiently. The present study aims to optimize this profile by numerical simulations. In view of this, the elliptical-bladed profiles are tested at different sectional cut angles of θ = 45°, 47.5°, 50° and 55°. The shear stress transport (SST) k-ω turbulence model is used to simulate the flow field, and thereafter, the torque and power coefficients are obtained at the rotating conditions. From 2D simulation, pressure and velocity contours are generated and analyzed. 2D simulations are also carried out for a semi-circular bladed profile in order to have a direct comparison. The numerical study demonstrates an improved flow characteristics, and hence the power coefficient of the elliptical-bladed profile at = 47.5°. Finally, 3D simulation is carried out to visualize and analyze the flow field around the optimum elliptical-bladed rotor at a tip speed ratio of 0.8. The aspect ratio of the rotor for the 3D simulation is kept at 0.7.

scholarly journals PENGARUH KECEPATAN ANGIN DAN VARIASI JUMLAH SUDU TERHADAP UNJUK KERJA TURBIN ANGIN POROS HORIZONTAL

2013 ◽  
Vol 3 (1) ◽  
Author(s):  
Firman Aryanto ◽  
Made Mara ◽  
Made Nuarsa
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Mechanical Energy ◽  
Performance Testing ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Maximum Speed ◽  
Horizontal Axis Wind Turbine ◽  
Wind Speeds

The wind turbine is a device that converts wind energy into mechanical energy and then converted into electrical energy through a generator. Horizontal axis wind turbines can increase the efficiency to get the maximum power coefficient. One was using the blade numerous. Maximum efisiensi system will increase the number of watts (power) generated so as to obtain a certain number of watts by simply using the number of windmills lessThe object of this research is the performance testing horizontal axis wind turbine with wind speed variation and variation in terms of the number of blade Efisiensi system (𝜂 )  and Tip Speed Ratio (TSR). Research conducted with the wind coming from the source to the Wind Tunnel fan to direct wind. Wind speed is used there are three variations of the 3 m/s, 3.5 m/s, and 4 m/s and varying the amount of blade that is 3, 4, 5 and 6 blade.The results showed that the best 𝜂  values obtained at a maximum wind speed of 4 m / s and the number of blade 5 with a value of 3.07% 𝜂, whereas 𝜂 smallest value obtained at wind speeds of 3 m/s and the number of blade 3 that the value of 0.05% 𝜂. For TSR maximum value at a maximum speed of 4 m/s occurred in the number of blade 5 is equal to λ = 2.11, while the lowest value at wind speeds of 3 m/s resulting in blade number 3 is equal to λ = 1.49.

scholarly journals Evaluation of Energy in Wind Turbine System Using Probability Distribution

2018 ◽  
Vol 9 (2) ◽  
pp. 294
Author(s):  
Kalyan Sagar Kadali ◽  
L Rajaji
Keyword(s):  
Distribution Function ◽  
Wind Speed ◽  
Probability Distribution ◽  
Wind Turbine ◽  
Torque Control ◽  
Energy Output ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Wind Turbine System ◽  
Mean Wind Speed

In this work, annual energy output of a variable speed wind turbine is analyzed using annual Weibull wind speed probability distribution function. The power coefficient variety with tip speed proportion in torque control district and pitch point variety for most extreme power yield from wind turbine are examined for distinguishing control framework parameters. The wind turbine power output and variation of power coefficient with tip speed ratio as well as pitch angle are examined / reported using annual Wei bull distribution function. Finally the variation of the estimated annual energy output of the given wind turbine with the mean wind speed is presented.

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