scholarly journals System Efficiency of a Tap Transformer Based Grid Connection Topology Applied on a Direct Driven Generator for Wind Power

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Senad Apelfröjd ◽  
Sandra Eriksson
Keyword(s):  
Full Range ◽  
Vertical Axis ◽  
Base Case ◽  
Resistive Load ◽  
System Efficiency ◽  
Variable Speed ◽  
Vertical Axis Wind Turbine ◽  
Wind Speeds ◽  
Grid Connection ◽  
Set Up

Results from experiments on a tap transformer based grid connection system for a variable speed vertical axis wind turbine are presented. The tap transformer based system topology consists of a passive diode rectifier, DC-link, IGBT inverter, LCL-filter, and tap transformer. Full range variable speed operation is enabled by using the different step-up ratios of a tap transformer. Simulations using MATLAB/Simulink have been performed in order to study the behavior of the system. A full experimental set up of the system has been used in the laboratory study, where a clone of the on-site generator was driven by an induction motor and the system was connected to a resistive load to better evaluate the performance. Furthermore, the system is run and evaluated for realistic wind speeds and variable speed operation. For a more complete picture of the system performance, a case study using real site Weibull parameters is done, comparing different tap selection options. The results show high system efficiency at nominal power and an increase in overall power output for full tap operation in comparison with the base case, a standard transformer. In addition, the loss distribution at different wind speeds is shown, which highlights the dominant losses at low and high wind speeds. Finally, means for further increasing the overall system efficiency are proposed.

scholarly journals Evaluation of Harmonic Content from a Tap Transformer Based Grid Connection System for Wind Power

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
S. Apelfröjd ◽  
S. Eriksson
Keyword(s):  
Harmonic Distortion ◽  
Synchronous Generator ◽  
Vertical Axis ◽  
Resistive Load ◽  
Variable Speed ◽  
Vertical Axis Wind Turbine ◽  
Grid Connection ◽  
Harmonic Content ◽  
Connection System ◽  
Set Up

Simulations done in MATLAB/Simulink together with experiments conducted at the Ångströms laboratory are used to evaluate and discuss the total harmonic distortion (THD) and total demand distortion (TDD) of a tap transformer based grid connection system. The grid connection topology can be used with different turbine and generator topologies and is here applied on a vertical axis wind turbine (VAWT) with a permanent magnet synchronous generator (PMSG) and its operational scheme. The full variable-speed wind conversion system consists of a diode rectifier, DC link, IGBT inverter, LCL-filter, and tap transformer. The full variable-speed operation is enabled by the use of the different step-up ratios of the tap transformer. In the laboratory study, a full experimental setup of the system was used, a clone of the on-site PMSG driven by a motor was used, and the grid was replaced with a resistive load. With a resistive load, grid harmonics and possible unbalances are removed. The results show a TDD and THD below 5% for the full operating range and harmonic values within the limits set up by IEEE-519. Furthermore, a change in tap, going to a lower step-up ratio, results in a reduction in both THD and TDD for the same output power.

Momentum Analytical Model of a Circulation Controlled Vertical Axis Wind Turbine

2009 ◽  
Author(s):  
Jay P. Wilhelm ◽  
Chad Panther ◽  
Franz A. Pertl ◽  
James E. Smith
Keyword(s):  
Wind Turbine ◽  
Analytical Model ◽  
Vertical Axis ◽  
Power Production ◽  
Circulation Control ◽  
Vertical Axis Wind Turbine ◽  
Trailing Edge ◽  
Operating Range ◽  
Wind Speeds ◽  
Stream Tubes

A possible method for analytically modeling a CC-VAWT (Circulation Controlled Vertical Axis Wind Turbine) is the momentum model, based upon the conservation of momentum principal. This model can consist of a single or multiple stream tubes and/or upwind and downwind partitions. A large number of stream tubes and the addition of the partition can increase the accuracy of the model predictions. The CC-VAWT blade has blowing slots located on the top and bottom trailing edges and have the capability to be site controlled in multiple sections along the span of the blade. The turbine blade, augmented to include circulation control capabilities, replaces the sharp trailing edge of a standard airfoil with a rounded surface located adjacent to the blowing slots. Circulation control (CC), along with a rounded trailing edge, induces the Coanda effect, entraining the flow field near the blowing slots thus preventing or delaying separation. Ultimately, circulation control adds momentum due to the mass flow of air coming out of the blowing slots, but is negligible compared to the momentum of the free stream air passing through the area of the turbine. In order to design for a broader range of operating speeds that will take advantage of circulation control, an analytical model of a CC-VAWT is helpful. The analytical modeling of a CC-VAWT could provide insight into the range of operational speeds in which circulation control is beneficial. The ultimate goal is to increase the range of operating speeds where the turbine produces power. Improvements to low-speed power production and the elimination or reduction of startup assistance could be possible with these modifications. Vertical axis wind turbines are typically rated at a particular ratio of rotational to wind speed operating range. In reality, however, wind speeds are variant and stray from the operating range causing the power production of a wind turbine to suffer. These turbines, unless designed specifically for low speed operation, may require rotational startup assistance. The added lift due to circulation control at low wind speeds, under certain design conditions, will allow the CC-VAWT to produce more power than a conventional VAWT of the same size. Circulation control methods, such as using blowing slots on the trailing edge are modeled as they are applied to a VAWT blade. A preliminary CC-VAWT was modeled using a standard NACA 0018 airfoil, modified to include blowing slots and a rounded trailing edge. This paper describes an analytical momentum model that can be used to predict the preliminary performance of a CC-VAWT.

scholarly journals Prototype Hybrid Power Plant of Solar Panel and Vertical Wind Turbine as a Provider of Alternative Electrical Energy at Kenjeran Beach Surabaya

2020 ◽  
Vol 2 (3) ◽  
pp. 108-113
Author(s):  
Anggara Trisna Nugraha ◽  
Dadang Priyambodo
Keyword(s):  
Solar Energy ◽  
Wind Energy ◽  
Wind Turbine ◽  
Electrical Energy ◽  
Vertical Axis ◽  
Solar Panel ◽  
Vertical Axis Wind Turbine ◽  
Energy Potential ◽  
Tropical Country ◽  
Wind Speeds

Indonesia, which is a tropical country, has a very large potential for solar energy because of its area that stretches across the equator, with a radiation magnitude of 4.80 kWh / m2 / day or equivalent to 112,000 GWp. On the other hand, the earth receives solar power of 1.74 x 1017 W / hour and about 1-2% of it is converted into wind energy. However, from the total energy potential, Indonesia has only utilized around 10 MWp for solar energy and not much different, wind energy, whose utilization is planned to reach 250 MW in 2025, has only been utilized around 1 MW of the total existing potential. With this potential, to be able to supply additional power and help save energy for existing facilities in the building, a Prototype of Solar Panel Hybird and Vertical Axis Wind Turbine was created. The design of this prototype is a combination of savonious type turbines and solar panels, where the use of this type of turbine is because it can rotate at low wind speeds (low wind velocity) and its construction is very simple.

Research on Matching Characteristics of Wind Turbine and Generator for Small H-shaped Vertical Axis Wind Turbine

2021 ◽  
Author(s):  
Yong-Chao Xie ◽  
Jin-Yan Shi
Keyword(s):  
Wind Turbine ◽  
Characteristic Curve ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Vertical Axis Wind Turbine ◽  
Aerodynamic Parameter ◽  
Wind Speeds ◽  
Wheel Model ◽  
Grid Division ◽  
Wind Turbine Rotor

Based on the small H-shaped vertical axis wind wheel model (NACA0016), a CFD wind wheel model was constructed. Based on the principle of moving grid, the grid division of the CFD wind wheel model is completed by using GAMBIT software, and the boundary conditions such as the inlet boundary and the outlet boundary are set reasonably. Then, the turbulence model and the couple algorithm are used to carry out transient simulation calculations, and finally the aerodynamic parameter curves of the two-dimensional CFD wind wheel model are obtained. Based on this, the matching characteristics of the wind turbine and generator of the small H-shaped vertical axis wind turbine are studied. The research results show as follows: when the incoming wind speeds change in range of (2 m/s, 12 m/s), and the power characteristic curve and torque characteristic curve of the generator wind wheel are respectively overlap the best power curve and best torque of the generator, the matching characteristics of the small H-shaped vertical axis wind turbine rotor and generator are optimal, which provides reference for carrying out related research.

On the Design of a Vertical Axis Wind Turbine for Use in Rural Communities

2009 ◽  
Author(s):  
Allison Johnston ◽  
Jesse French ◽  
John Henshaw
Keyword(s):  
Rural Communities ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Water Pump ◽  
Direct Drive ◽  
Vertical Axis Wind Turbine ◽  
Wind Speeds ◽  
Design Specifications ◽  
North East ◽  
High Winds

The paper describes the design specifications for a hand built wind turbine that is optimally used in regions such as North East China. The authors have developed a design for a home sized wind turbine. A region with some of the highest wind speeds in the world, North East Jilin is an ideal site for vertical axis wind power. Because of its ability to generate power best in high winds, a Darrieus-type turbine is the modified and tested design. Since it is low to the ground, it can be raised and lowered for maintenance and repair without need of expensive equipment or cranes. The design employs a direct drive shaft that can attach to a water pump, an air compressor, or a car alternator. In this way the owner of the turbine can pump water, compress air, or generate electricity depending on personal need. The turbine was designed considering probable implementation locations, and therefore all materials and fabrication techniques are easily accessible by the rural Chinese. The turbine was constructed and raised, and testing was begun.

Design of a Vertical-Axis Wind Turbine Test Facility

2009 ◽  
Author(s):  
Jonathan Kweder ◽  
Patrick Wildfire ◽  
Christina Yarborough ◽  
James E. Smith
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Structural Testing ◽  
Test Facility ◽  
Vertical Axis Wind Turbine ◽  
Freestream Velocity ◽  
Temperature Changes ◽  
Wind Speeds ◽  
Physical Simulations ◽  
World Environment

Physical simulations of fatigue and wear of a vertical axis wind turbine (VAWT) are extremely complex and difficult to evaluate both analytically and numerically. The primary difficulty is simulating the fatigue at the point that the airfoil attaches to the wind turbine structure. Physical testing of VAWT models would provide a simpler method of analyzing the dynamics of a prototype. However, accurate reproduction of the aerodynamic loading imposed on a VAWT body due to the rotational wake is difficult to replicate. To truly incorporate a real world environment, the test facility needs to be exposed to a random, but measurable environment. This leads to the design and development of an outdoor wind turbine test facility. This proposed test facility will consist of an outdoor structure equipped with a 350 horsepower electric motor to turn an 88 inch diameter propeller which will drive the wind turbine model at specific rotational speeds. The propeller will be able to simulate wind speeds over the entire spectrum of 0 to 75 feet per second. The aerodynamic control of the freestream velocity and in turn, the model, will provide an accurate representation of the aerodynamic loadings experienced by the wind turbines tested. In addition to structural testing, this facility will introduce measurable environmental effects, such as wind gusts, pressure variation, and temperature changes to the model in order to create an accurate setting under which the model can be studied.

Influence of Fixed Pitch Angle on the Performance of Small Scale H-Darrieus

2016 ◽  
Author(s):  
Teresa Parra-Santos ◽  
Diego J. Palomar Trullen ◽  
Armando Gallegos ◽  
Cristobal N. Uzarraga ◽  
Maria Regidor-Sanchez ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Pitch Angle ◽  
Stokes Equations ◽  
Vertical Axis ◽  
Navier Stokes ◽  
Small Scale ◽  
Vertical Axis Wind Turbine ◽  
Sst Turbulence Model ◽  
Set Up ◽  
Fixed Pitch

The performance of a Vertical Axis Wind Turbine (VAWT) is numerically analyzed. Influence of fixed pitch angle is studied to get tendencies on the characteristic curves. The set up corresponds with an H-Darrieus with three straight NACA airfoils attached to a vertical shaft. Two-dimensional, transient, Navier Stokes equations are solved with a Third-Order Muscl scheme using SIMPLE to couple pressure and velocity. At least three revolutions must be simulated to get the periodic behaviour. Transition SST turbulence model has been chosen based on literature. Pitch angles of −6° and −10° have been analyzed with Tip Speed Ratios ranging from 0.7 and 1.6. The pitch angle of −10° improves the performance of the wind turbine. Instantaneous and averaged power coefficients as well as detailed flow field around the airfoils are shown.

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