Difference between pages "Wind Energy" and "Wind Energy Background"

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This report presents a brief introduction to wind energy and technologies available for horizontal wind turbines. A detailed taxonomy for horizontal axis wind turbines is presented covering parts of the turbine, control systems, applications among others. A detailed landscape analysis of patent and non-patent literature is done with a focus on Doubly-fed Induction Generators (DFIG) used in the horizontal axis wind turbines for efficient power generation. The product information of major players in the market is also captured for Doubly-fed Induction Generators. The final section of the report covers the existing and future market predictions for wind energy-based power generation.
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==Brief History of Wind Energy==
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[[Image:DFIG.gif|right|thumb|600px| '''[http://www.windsimulators.co.uk/DFIG.htm DFIG Working Principle]''']]
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Although the use of wind power started around 5000 BC, but electric power generation through wind energy started in 18th century and increasing drastically in 19th and 20th centuries. A brief view on developments on wind power sector are listed below.
 +
[[Image:totalcapacityworld2009.JPEG|thumb|right|400px|Fig 1 '''[http://www.wwindea.org/home/index.php Development of wind power worldwide]''']]
 +
* [http://www.brighthub.com/environment/renewable-energy/articles/71440.aspx 1887]        :  Prof. James Blyth of Scotland used windmills for generating electricity.
 +
* [http://www.brighthub.com/environment/renewable-energy/articles/71440.aspx 1888]      :  Charles Brush developed the first wind-powered turbine that generated electricity in the United States based on emulated James Blyth work.
 +
* [http://www.brighthub.com/environment/renewable-energy/articles/71440.aspx 1927]      :  Joe Jacobs and Marcellus Jacobs improved the wind turbine generator for use in farms.
 +
* [http://www.brighthub.com/environment/renewable-energy/articles/71440.aspx 1931] : development of Darrieus wind turbine. It is a vertical axis turbine that rotates with wind from any direction.
 +
* 1941: Largest mega watt range wind turbine was connected to the local electrical distribution system on the mountain known as Grandpa's Knob in Castleton, Vermont, USA.  
 +
* 1971: Denmark installed the first offshore wind farms
 +
* 1990s: More than 2200 MW capacity of wind turbines are installed in california.
 +
* 2003: the largest offshore wind farm North Hoyle  was built in  the United Kingdom.
 +
* 2003-2010: Research is going is on wind turbines in blades structures, generators, operation and protection, efficiency of wind turbines.
 +
Source:[[Media:windenergy.pdf| Wind Energy]]<br>
 +
The total installed wind power capacity from 2001 to 2010 is shown in fig. 1.  All wind turbines installed by the end of year 2009 worldwide are generating 340 TWh per annum.
 +
The country wise share of wind energy by the end of year 2009 is shown in fig. 2.
 +
[[Image:countryshare.JPEG|thumb|center|350px|Fig 2 '''[http://www.wwindea.org/home/index.php  Country share of total capacity]''']]
  
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=Introduction=
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==Working Principle of Wind Turbine ==
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* We have been using wind power at least since 5000 BC to propel sailboats and sailing ships, and architects have used wind-driven natural ventilation in buildings since similarly ancient times. The use of wind to provide mechanical power came later.
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Wind is air in motion. It is a form of solar energy. Solar radiation heats every part of the Earth’s surface unevenly due to irregularities and rotation of earth. The flow of wind patterns are modified by the earth's terrain, bodies of water, and vegetative cover. When air moves, causing wind, it has kinetic energy. The kinetic energy of wind can be captured by a wind turbine and converted to other forms of energy such as electricity or mechanical power.
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* Harnessing renewable alternative energy is the ideal way to tackle the energy crisis, with due consideration given to environmental pollution, that looms large over the world.
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* Renewable energy is also called "clean energy" or "green power" because it doesn’t pollute the air or the water. Wind energy is one such renewable energy source that harnesses natural wind power.<br>
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[[Image:windenergy windprinciple1.png|center|550px|thumb|Fig 3 '''[http://www.atlantissolar.com/wind_story.html Wind turbine principle]''']]
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== Read More? ==
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Click on [[Wind Energy Background]] to read more about wind energy.
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In order to overcome the problems associated with fixed speed wind turbine system and to maximize the wind energy capture, many new wind farms are employing variable speed wind energy conversion systems (WECS) with doubly-fed induction generator (DFIG). It is the most popular and widely used scheme for the wind generators due to its advantages.
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Sources:[http://windeis.anl.gov/guide/basics/index.cfm Wind Energy Basics],[http://www1.eere.energy.gov/windandhydro/wind_how.html#inside How Wind Turbines Work]
  
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For variable-speed systems with limited variable-speed range, e.g. ±30% of synchronous speed, the doubly-fed induction generator(DFIG) can be an interesting solution. This is mainly due to the fact that the power electronic converter only has to handle a fraction (20-30%) of the total power as the converters are connected to the rotor and not to the stator. Therefore, the losses in the power electronic converter can be reduced, compared to a system where the converter has to handle the total power. The overall structure of wind power generation through DFIG as shown in the figure below.
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==Horizontal Axis and Vertical Axis Wind Turbines ==
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Wind turbines are mainly classified into two types based on the axis in which turbine rotates. They are Horizontal axis wind turbine(HAWT) and vertical axis wind turbine (VAWT). The table below presented, describes the advantages and disadvantages of HAWT's and VAWT's.
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= Doubly-fed Induction Generator: Search Strategy =
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The present study on the IP activity in the area of horizontal axis wind turbines with focus on '''''Doubly-fed Induction Generator (DFIG)''''' is based on a search conducted on Thomson Innovation.  
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==Control Patents==
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{|border="2" cellspacing="0" cellpadding="4" width="100%"
 
{|border="2" cellspacing="0" cellpadding="4" width="100%"
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|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S. No.'''</font>
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| align = "center" bgcolor = "#83caff"|'''Horizontal axis wind turbines'''
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|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Patent/Publication No.'''</font>
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| align = "center" bgcolor = "#83caff"|'''Vertical axis wind turbines'''
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|align = "center" bgcolor = "#4F81BD" width="15%"|<font color="#FFFFFF">'''Publication Date<br>'''(mm/dd/yyyy)</font>
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|-
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|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Assignee/Applicant'''</font>
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|
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|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Title'''</font>
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* It is mounted on top of a tower ,requires huge towers leads to complex in operation, maintenance and high initial costs.
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|- valign="top"
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* It operates only with upstream or down stream wind directions.
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|align = "center" bgcolor = "#DCE6F1"|1
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* It can be constructed in off-shores.
−
|align = "center" bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6278211.PN.&OS=PN/6278211&RS=PN/6278211 US6278211]</u></font>
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* It produces large amount of electricity with high efficiency.
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|align = "center" bgcolor = "#DCE6F1"|08/02/01
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|
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|bgcolor = "#DCE6F1"|Sweo Edwin
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* These are easy to build and maintain, safer, easier to transport and they can be mounted close to the ground.
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|bgcolor = "#DCE6F1"|Brush-less doubly-fed induction machines employing dual cage rotors
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* These can handle much turbulence in wind than horizontal wind turbines.
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|- valign="top"
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* Mostly it can be constructed with two blades
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|align = "center"|2
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* It operates with any direction of wind
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|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6954004.PN.&OS=PN/6954004&RS=PN/6954004 US6954004]</u></font>
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* Production of electricity is less due to low wind speeds near to ground
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|align = "center"|10/11/05
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|-
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|Spellman High Voltage Electron
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|[[Image:Horizontal.jpg|center|thumb|Fig 4(a)'''[http://www.windturbinesnow.com/horizontalaxis-windturbines.htm Horizontal axis wind turbine]''']]
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|Doubly fed induction machine
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|[[Image:vertical.jpg|center|thumb|Fig 4(b)'''[http://www.solarpowerwindenergy.org/2009/12/25/types-of-wind-turbines/ Vertical axis wind turbine]''']]
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|- valign="top"
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−
|align = "center" bgcolor = "#DCE6F1"|3
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−
|align = "center" bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7411309.PN.&OS=PN/7411309&RS=PN/7411309 US7411309]</u></font>
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−
|align = "center" bgcolor = "#DCE6F1"|08/12/08
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|bgcolor = "#DCE6F1"|Xantrex Technology
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|bgcolor = "#DCE6F1"|Control system for doubly fed induction generator
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−
|- valign="top"
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−
|align = "center"|4
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−
|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7485980.PN.&OS=PN/7485980&RS=PN/7485980 US7485980]</u></font>
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−
|align = "center"|02/03/09
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−
|Hitachi
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|Power converter for doubly-fed power generator system
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|- valign="top"
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|align = "center" bgcolor = "#DCE6F1"|5
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−
|align = "center" bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7800243.PN.&OS=PN/7800243&RS=PN/7800243 US7800243]</u></font>
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−
|align = "center" bgcolor = "#DCE6F1"|09/21/10
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−
|bgcolor = "#DCE6F1"|Vestas Wind Systems
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|bgcolor = "#DCE6F1"|Variable speed wind turbine with doubly-fed induction generator compensated for varying rotor speed
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|- valign="top"
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|align = "center"|6
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|align = "center"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7830127.PN.&OS=PN/7830127&RS=PN/7830127 US7830127]</u></font>
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−
|align = "center"|11/09/10
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−
|Wind to Power System
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|Doubly-controlled asynchronous generator
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|-
 
|-
 
|}
 
|}
  
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==IPC/ECLA Classes==
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Source:[http://www.windpowertv.com/forum/index.php?topic=18.0 Different types of wind turbines]
 +
 
 +
=Horizontal Axis Wind Turbines=
 +
 
 +
[[Image:HWAT1.PNG|right|131px]]
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 +
 
 +
All grid-connected commercial wind turbines today are built with a horizontal axis type rotor which is installed on top of a tower. Most horizontal axis turbines built today are two- or three-bladed, although some have fewer or more blades. The purpose of the rotor is to convert the linear motion of the wind into rotational energy that can be used to drive a generator. Most of the systems have a gearbox, which turns the slow rotation of the blades into a quicker rotation that is more suitable to drive an electrical generator.
 +
 
 +
Click on the link below to see detailed description about horizontal axis wind turbines.<br>
 +
<font size="3"><span style="color: rgb(253, 90, 255);">'''[[Different Types and Parts of a Horizontal Axis Wind Turbines]]'''</span></font>
 +
 
 +
=Electrical Generating Systems=
 +
 
 +
The various types of electrical generating systems used in wind energy systems are shown in figure.
 +
[[Image:generator.png|center|800px]]
 +
 
 +
Source:[[Media:windturbinegenerators.pdf|Wind Turbine Generators]]
 +
 
 +
The most commonly used generator systems applied in wind turbines are are explained below.
  
 
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 
{|border="2" cellspacing="0" cellpadding="4" width="100%"
−
|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S. No.'''</font>
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| align = "center" bgcolor = "#83caff"|
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''IPC/ECLA'''</font>
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| align = "center" bgcolor = "#83caff"|'''Fixed speed generating systems'''
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Definition'''</font>
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| align = "center" bgcolor = "#83caff"|'''Variable speed generating systems'''
−
|-valign="top"
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| align = "center" bgcolor = "#83caff"|'''Doubly fed induction generator'''
−
|align = "center" bgcolor = "#DCE6F1"|1
+
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=F03D0009000000 F03D9/00]</u></font>
+
−
|bgcolor = "#DCE6F1"|Machines or engines for liquids; wind, spring, or weight motors; producing mechanical power or a reactive propulsive thrust, not otherwise provided for / Wind motors / '''Adaptations of wind motors for special use; Combination of wind motors with apparatus driven thereby (aspects predominantly concerning driven apparatus)'''
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|-valign="top"
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|align = "center"|2
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|<font color="#0000FF"><u>[http://v3.espacenet.com/eclasrch?classification=ecla&locale=en_EP&ECLA=f03d9/00c F03D9/00C]</u></font>
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−
|Machines or engines for liquids; wind, spring, or weight motors; producing mechanical power or a reactive propulsive thrust, not otherwise provided for / Wind motors / Adaptations of wind motors for special use; Combination of wind motors with apparatus driven thereby (aspects predominantly concerning driven apparatus) / '''The apparatus being an electrical generator'''  
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−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|3
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−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.wipo.int/ipcpub/#&refresh=page&notion=scheme&version=20110101&symbol=H02J0003380000 H02J3/38]</u></font>
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|bgcolor = "#DCE6F1"|Generation, conversion, or distribution of electric power / Circuit arrangements or systems for supplying or distributing electric power; systems for storing electric energy / Circuit arrangements for ac mains or ac distribution networks / '''Arrangements for parallely feeding a single network by two or more generators, converters or transformers'''
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−
|-valign="top"
+
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|align = "center"|4
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|<font color="#0000FF"><u>[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=H02K0017420000 H02K17/42]</u></font>
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−
|Generation, conversion, or distribution of electric power / Dynamo-electric machines / Asynchronous induction motors; Asynchronous induction generators / '''Asynchronous induction generators'''
+
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|5
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−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=H02P0009000000 H02P9/00]</u></font>
+
−
|bgcolor = "#DCE6F1"|Generation, conversion, or distribution of electric power / Control or regulation of electric motors, generators, or dynamo-electric converters; controlling transformers, reactors or choke coils / '''Arrangements for controlling electric generators for the purpose of obtaining a desired output'''
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|-
 
|-
−
|}
+
| Structure
 +
| [[Image:fixed.png|center|250px]]
 +
| [[Image:variable.png|center|250px]]
 +
| [[Image:dfigg.png|center|250px]]
  
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==US Classes==
 
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{|border="2" cellspacing="0" cellpadding="4" width="100%"
 
−
|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S. No.'''</font>
 
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|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''US Class'''</font>
 
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|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Definition'''</font>
 
 
|-
 
|-
−
|align = "center" bgcolor = "#DCE6F1"|1
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| Machines
−
|align = "center" bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.uspto.gov/web/patents/classification/uspc290/sched290.htm#C290S044000 290/044]</u></font>
+
| SQIG
−
|bgcolor = "#DCE6F1"|Prime-mover dynamo plants / electric control / Fluid-current motors / '''Wind '''
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| PMSG/WRSG/WRIG
−
|-
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| DFIG
−
|align = "center"|2
+
−
|align = "center"|<font color="#0000FF"><u>[http://www.uspto.gov/web/patents/classification/uspc290/sched290.htm#C290S055000 290/055]</u></font>
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−
|Prime-mover dynamo plants / Fluid-current motors / '''Wind'''
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−
|-
+
−
|align = "center" bgcolor = "#DCE6F1"|3
+
−
|align = "center" bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.uspto.gov/web/patents/classification/uspc318/sched318.htm#C318S727000 318/727]</u></font>
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−
|bgcolor = "#DCE6F1"|Electricity: motive power systems / '''Induction motor systems '''
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−
|-
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−
|align = "center"|4
+
−
|align = "center"|<font color="#0000FF"><u>[http://www.uspto.gov/web/patents/classification/uspc322/sched322.htm#C322S047000 322/047]</u></font>
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−
|Electricity: single generator systems / Generator control / '''Induction generator '''
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−
|-
+
−
|}
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==Concept Table==
 
−
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 
−
|align = "center" bgcolor = "#4F81BD" rowspan = "2" width="38"|<font color="#FFFFFF">'''S. No.'''</font>
 
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Concept 1'''</font>
 
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Concept 2'''</font>
 
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Concept 3'''</font>
 
 
|-
 
|-
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|align = "center" bgcolor = "#95B3D7"|'''Doubly Fed'''
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| Advantages
−
|align = "center" bgcolor = "#95B3D7"|'''Induction'''
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| <nowiki>* Simple and low cost </nowiki>
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|align = "center" bgcolor = "#95B3D7"|'''Generator'''
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<nowiki>* Low maintenance  </nowiki>
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|-
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| <nowiki>* Complete control of real and reactive powers</nowiki>
−
|align = "center" bgcolor = "#DCE6F1"|1
+
 
−
|bgcolor = "#DCE6F1"|doubly fed
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<nowiki>* High energy efficiency </nowiki>
−
|bgcolor = "#DCE6F1"|induction
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| <nowiki>* Reduced capacity converter</nowiki>
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|bgcolor = "#DCE6F1"|generator
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−
|-
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<nowiki>* Decoupled control of active and reactive power flow</nowiki>
−
|align = "center"|2
+
 
−
|double output
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<nowiki>* Smooth grid connection</nowiki>
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|asynchronous
+
−
|machines
+
−
|-
+
−
|align = "center" bgcolor = "#DCE6F1"|3
+
−
|bgcolor = "#DCE6F1"|dual fed
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−
|bgcolor = "#DCE6F1"|
+
−
|bgcolor = "#DCE6F1"|systems
+
−
|-
+
−
|align = "center"|4
+
−
|dual feed
+
−
|
+
−
|
+
−
|-
+
−
|align = "center" bgcolor = "#DCE6F1"|5
+
−
|bgcolor = "#DCE6F1"|dual output
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−
|bgcolor = "#DCE6F1"|
+
−
|bgcolor = "#DCE6F1"|
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−
|-
+
−
|}
+
  
−
==Thomson Innovation Search==
 
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'''Database:''' Thomson Innovation<br>
 
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'''Patent coverage:''' US EP WO JP DE GB FR CN KR DWPI<br>
 
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'''Time line:''' 01/01/1836 to 07/03/2011
 
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{|border="2" cellspacing="0" cellpadding="4" width="100%"
 
−
|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S. No.'''</font>
 
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Concept'''</font>
 
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Scope'''</font>
 
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|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Search String'''</font>
 
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|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''No. of Hits'''</font>
 
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|-valign="top"
 
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|align = "center" bgcolor = "#DCE6F1"|1
 
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|bgcolor = "#DCE6F1"|Doubly-fed Induction Generator: Keywords(broad)
 
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|bgcolor = "#DCE6F1"|Claims, Title, and Abstract
 
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|bgcolor = "#DCE6F1"|(((((doubl<nowiki>*</nowiki>3 OR dual<nowiki>*</nowiki>3 OR two) ADJ3 (power<nowiki>*</nowiki>2 OR output<nowiki>*</nowiki>4 OR control<nowiki>*</nowiki>4 OR fed OR feed<nowiki>*</nowiki>3)) NEAR5 (induction OR asynchronous)) NEAR5 (generat<nowiki>*</nowiki>3 OR machine<nowiki>*</nowiki>1 OR dynamo<nowiki>*</nowiki>1)) OR dfig or doig)
 
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|align = "right" bgcolor = "#DCE6F1"|864
 
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|-valign="top"
 
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|align = "center"|2
 
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|Doubly-fed Induction Generator: Keywords(broad)
 
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|Full Spec.
 
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|(((((doubl<nowiki>*</nowiki>3 OR dual<nowiki>*</nowiki>3 OR two) ADJ3 (power<nowiki>*</nowiki>2 OR output<nowiki>*</nowiki>1 OR control<nowiki>*</nowiki>4 OR fed OR feed<nowiki>*</nowiki>3)) NEAR5 (generat<nowiki>*</nowiki>3 OR machine<nowiki>*</nowiki>1 OR dynamo<nowiki>*</nowiki>1))) OR dfig or doig)
 
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|align = "center"|<nowiki>-</nowiki>
 
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|-valign="top"
 
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|align = "center" bgcolor = "#DCE6F1"|3
 
−
|bgcolor = "#DCE6F1"|Induction Machine: Classes
 
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|bgcolor = "#DCE6F1"|US, IPC, and ECLA Classes
 
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|bgcolor = "#DCE6F1"|((318/727 OR 322/047) OR (H02K001742))
 
−
|align = "center" bgcolor = "#DCE6F1"|<nowiki>-</nowiki>
 
−
|-valign="top"
 
−
|align = "center"|4
 
−
|Generators: Classes
 
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|US, IPC, and ECLA Classes
 
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|((290/044 OR 290/055) OR (F03D000900C OR H02J000338 OR F03D0009<nowiki>*</nowiki> OR H02P0009<nowiki>*</nowiki>))
 
−
|align = "center"|<nowiki>-</nowiki>
 
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|-valign="top"
 
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|align = "center" bgcolor = "#DCE6F1"|5
 
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|bgcolor = "#DCE6F1"|Combined Query
 
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|align = "center" bgcolor = "#DCE6F1"|<nowiki>-</nowiki>
 
−
|align = "left" bgcolor = "#DCE6F1"|2 AND 3
 
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|align = "right" bgcolor = "#DCE6F1"|108
 
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|-valign="top"
 
−
|align = "center"|6
 
−
|Combined Query
 
−
|align = "center"|<nowiki>-</nowiki>
 
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|align = "left"|2 AND 4
 
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|align = "right"|757
 
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|-valign="top"
 
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|align = "center" bgcolor = "#DCE6F1"|7
 
−
|bgcolor = "#DCE6F1"|French Keywords
 
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|bgcolor = "#DCE6F1"|Claims, Title, and Abstract
 
−
|bgcolor = "#DCE6F1"|((((doubl<nowiki>*</nowiki>3 OR dual<nowiki>*</nowiki>3OR ADJ two OR deux) NEAR4 (nourris OR feed<nowiki>*</nowiki>3 OR puissance OR sortie<nowiki>*</nowiki>1 OR contrôle<nowiki>*</nowiki>1)) NEAR4 (induction OR asynchron<nowiki>*</nowiki>1) NEAR4 (générateur<nowiki>*</nowiki>1 OR generator<nowiki>*</nowiki>1 OR machine<nowiki>*</nowiki>1 OR dynamo<nowiki>*</nowiki>1)) OR dfig or doig)
 
−
|align = "right" bgcolor = "#DCE6F1"|257
 
−
|-valign="top"
 
−
|align = "center"|8
 
−
|German Keywords
 
−
|Claims, Title, and Abstract
 
−
|(((((doppel<nowiki>*</nowiki>1 OR dual OR two OR zwei) ADJ3 (ausgang OR ausgänge OR kontroll<nowiki>*</nowiki> OR control<nowiki>*</nowiki>4 OR gesteuert OR macht OR feed<nowiki>*</nowiki>1 OR gefüttert OR gespeiste<nowiki>*</nowiki>1)) OR (doppeltgefüttert OR doppeltgespeiste<nowiki>*</nowiki>1)) NEAR4 (((induktion OR asynchronen) NEAR4 (generator<nowiki>*</nowiki>2 OR maschine<nowiki>*</nowiki>1 OR dynamo<nowiki>*</nowiki>1)) OR (induktion?maschinen OR induktion?generatoren OR asynchronmaschine OR asynchrongenerator))) OR dfig)
 
−
|align = "right"|302
 
−
|-valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|9
 
−
|bgcolor = "#DCE6F1"|Doubly-fed Induction Generator: Keywords(narrow)
 
−
|bgcolor = "#DCE6F1"|Full Spec.
 
−
|bgcolor = "#DCE6F1"|(((((((doubl<nowiki>*</nowiki>3 OR dual<nowiki>*</nowiki>3) ADJ3 (power<nowiki>*</nowiki>2 OR output<nowiki>*</nowiki>4 OR control<nowiki>*</nowiki>4 OR fed OR feed<nowiki>*</nowiki>3))) NEAR5 (generat<nowiki>*</nowiki>3 OR machine<nowiki>*</nowiki>1 OR dynamo<nowiki>*</nowiki>1))) SAME wind) OR (dfig SAME wind))
 
−
|align = "right" bgcolor = "#DCE6F1"|1358
 
−
|-valign="top"
 
−
|align = "center"|10
 
−
|Combined Query
 
−
|align = "center"|<nowiki>-</nowiki>
 
−
|1 OR 2 OR 3 OR 4 OR 5 OR 6
 
−
|1807 ('''916''' unique)
 
 
|-
 
|-
−
|}
+
| Drawbacks
 +
|  <nowiki>* </nowiki>No control on real and reactive power
  
−
=Taxonomy=
+
<nowiki>* Less optimum power extraction capability</nowiki>
−
*''Use the mouse(click and drag/scroll up or down/click on nodes) to explore nodes in the detailed taxonomy''
+
 
−
*''Click on the red arrow adjacent to the node name to view the content for that particular node in the dashboard''
+
<nowiki>* Poor power factor</nowiki>
−
{|border="2" cellspacing="0" cellpadding="4" width="100%"
+
 
−
|<mm>[[Doubly_fed_Induction_Generator.mm|Interactive Mind-map|center|flash|Doubly-fed Induction Generator|600pt]]</mm>
+
<nowiki>* High mechanical stress on turbine mechanical components</nowiki>
−
|}
+
| <nowiki>* Additional cost of power electronics</nowiki>
 +
 
 +
<nowiki>* Limited fault ride through capability</nowiki>
 +
| <nowiki>* Regular maintenance of slip ring and gearbox</nowiki>
 +
 
 +
<nowiki>* Limited fault ride-through capability</nowiki>
  
−
=Sample Analysis=
 
−
A sample of 139 patents from the search is analyzed based on the taxonomy.
 
−
Provided a link below for sample spread sheet analysis for doubly-fed induction generators.<br>
 
−
===Patent Analysis===
 
−
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 
−
|align = "center" bgcolor = "#4F81BD" rowspan = "2" width="38"|<font color="#FFFFFF">'''S. No'''</font>
 
−
|align = "center" bgcolor = "#4F81BD" rowspan = "2" |<font color="#FFFFFF">'''Patent/Publication No.'''</font>
 
−
|align = "center" bgcolor = "#4F81BD" rowspan = "2" width="105"|<font color="#FFFFFF">'''Publication Date<br>'''(mm/dd/yyyy)</font>
 
−
|align = "center" bgcolor = "#4F81BD" rowspan = "2"|<font color="#FFFFFF">'''Assignee/Applicant'''</font>
 
−
|align = "center" bgcolor = "#4F81BD" rowspan = "2"|<font color="#FFFFFF">'''Title'''</font>
 
−
|align = "center" bgcolor = "#4F81BD" colspan = "2"|<font color="#FFFFFF">'''Dolcera Analysis'''</font>
 
−
|-
 
−
|align = "center" bgcolor = "#95B3D7"|'''Problem'''
 
−
|align = "center" bgcolor = "#95B3D7"|'''Solution'''
 
−
|-valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|1
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100117605%22.PGNR.&OS=DN/20100117605&RS=DN/20100117605 US20100117605]</u></font>
 
−
|align = "center" bgcolor = "#DCE6F1"|05/13/10
 
−
|bgcolor = "#DCE6F1"|Woodward
 
−
|bgcolor = "#DCE6F1"|Method of and apparatus for operating a double-fed asynchronous machine in the event of transient mains voltage changes
 
−
|bgcolor = "#DCE6F1"|The short-circuit-like currents in the case of transient mains voltage changes lead to a corresponding air gap torque which loads the drive train and transmission lines can damages or reduces the drive train and power system equipments.
 
−
|bgcolor = "#DCE6F1"|The method presents that the stator connecting with the network and the rotor with a converter. The converter is formed to set a reference value of electrical amplitude in the rotor, by which a reference value of the electrical amplitude is set in the rotor after attaining a transient mains voltage change, such that the rotor flux approaches the stator flux.
 
−
|-valign="top"
 
−
|align = "center"|2
 
−
|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100045040%22.PGNR.&OS=DN/20100045040&RS=DN/20100045040 US20100045040]</u></font>
 
−
|align = "center"|02/25/10
 
−
|Vestas Wind Systems
 
−
|Variable speed wind turbine with doubly-fed induction generator compensated for varying rotor speed
 
−
|The DFIG system has poor damping of oscillations within the flux dynamics due to cross coupling between active and reactive currents, which makes the system potentially unstable under certain circumstances and complicates the work of the rotor current controller. These oscillations ca damage the drive train mechanisms.
 
−
|A compensation block is arranged, which feeds a compensation control output to the rotor of the generator. The computation unit computes the control output during operation of the turbine to compensate partly for dependencies on a rotor angular speed of locations of poles of a generator transfer function, so that the transfer function is made independent of variations in the speed during operation of the turbine which eliminates the oscillations and increases the efficiency of the wind turbine.
 
−
|-valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|3
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090267572%22.PGNR.&OS=DN/20090267572&RS=DN/20090267572 US20090267572]</u></font>
 
−
|align = "center" bgcolor = "#DCE6F1"|10/29/09
 
−
|bgcolor = "#DCE6F1"|Woodward
 
−
|bgcolor = "#DCE6F1"|Current limitation for a double-fed asynchronous machine
 
−
|bgcolor = "#DCE6F1"|Abnormal currents can damage the windings in the doubly- fed induction generator. Controlling these currents with the subordinate current controllers cannot be an efficient way to extract the maximum amount of active power.
 
−
|bgcolor = "#DCE6F1"|The method involves delivering or receiving of a maximum permissible reference value of an active power during an operation of a double-fed asynchronous machine, where predetermined active power and reactive power reference values are limited to a calculated maximum permissible active and reactive power reference values, and hence ensures reliable regulated effect and reactive power without affecting the power adjustment, the rotor is electrically connected to a pulse-controlled inverter by slip rings with a static frequency changer, and thus a tension with variable amplitude and frequency is imposed in the rotor.
 
−
|-valign="top"
 
−
|align = "center"|4
 
−
|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090008944%22.PGNR.&OS=DN/20090008944&RS=DN/20090008944 US20090008944]</u></font>
 
−
|align = "center"|01/08/09
 
−
|Universidad Publica De Navarra
 
−
|Method and system of control of the converter of an electricity generation facility connected to an electricity network in the presence of voltage sags in said network
 
−
|Double-fed asynchronous generators are very sensitive to the faults that may arise in the electricity network, such as voltage sags. During the sag conditions the current which appears in said converter may reach very high values, and may even destroy it.
 
−
|During the event of a voltage sag occurring, the converter imposes a new set point current which is the result of adding to the previous set point current a new term, called demagnetizing current, It is proportional to a value of free flow of a generator stator. A difference between a value of a magnetic flow in the stator of the generator and a value of a stator flow associated to a direct component of a stator voltage is estimated. A value of a preset calculated difference is multiplied by a factor for producing the demagnetizing current.
 
−
|-valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|5
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7355295.PN.&OS=PN/7355295&RS=PN/7355295 US7355295]</u></font>
 
−
|align = "center" bgcolor = "#DCE6F1"|04/08/08
 
−
|bgcolor = "#DCE6F1"|Ingeteam Energy
 
−
|bgcolor = "#DCE6F1"|Variable speed wind turbine having an exciter machine and a power converter not connected to the grid
 
−
|bgcolor = "#DCE6F1"|a) The active switching of the semiconductors of the grid side converter injects undesirable high frequency harmonics to the grid.<br>b) The use of power electronic converters (4) connected to the grid (9) causes harmonic distortion of the network voltage.
 
−
|bgcolor = "#DCE6F1"|Providing the way that power is only delivered to the grid through the stator of the doubly fed induction generator, avoiding undesired harmonic distortion. <br>Grid Flux Orientation (GFO) is used to accurately control the power injected to the grid. An advantage of this control system is that it does not depend on machine parameters, which may vary significantly, and theoretical machine models, avoiding the use of additional adjusting loops and achieving a better power quality fed into the utility grid.
 
−
|-valign="top"
 
−
|align = "center"|6
 
−
|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220080203978%22.PGNR.&OS=DN/20080203978&RS=DN/20080203978 US20080203978]</u></font>
 
−
|align = "center"|08/28/08
 
−
|Semikron
 
−
|Frequency converter for a double-fed asynchronous generator with variable power output and method for its operation
 
−
|Optislip circuit with a resistor is used when speed is above synchronous speed, results in heating the resistor and thus the generator leads to limitation of operation in super synchronous range which results in tower fluctuations.
 
−
|Providing a back-to-back converter which contains the inverter circuit has direct current (DC) inputs, DC outputs, and a rotor-rectifier connected to a rotor of a dual feed asynchronous generator. A mains inverter is connected to a power grid, and an intermediate circuit connects one of the DC inputs with the DC outputs. The intermediate circuit has a semiconductor switch between the DC outputs, an intermediate circuit condenser between the DC inputs, and a diode provided between the semiconductor switch and the condenser. Thus the system is allowed for any speed of wind  and reduces the tower fluctuations.
 
−
|-valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|7
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070210651%22.PGNR.&OS=DN/20070210651&RS=DN/20070210651 US20070210651]</u></font>
 
−
|align = "center" bgcolor = "#DCE6F1"|09/13/07
 
−
|bgcolor = "#DCE6F1"|Hitachi
 
−
|bgcolor = "#DCE6F1"|Power converter for doubly-fed power generator system
 
−
|bgcolor = "#DCE6F1"|During the ground faults, excess currents is induced in the secondary windings and flows into power converter connected to secondary side and may damage the power converter. Conventional methods of increasing the capacity of the power converter increases system cost, degrade the system and takes time to activate the system to supply power again.
 
−
|bgcolor = "#DCE6F1"|The generator provided with a  excitation power converter connected to secondary windings of a doubly-fed generator via impedance e.g. reactor, and a diode rectifier connected in parallel to the second windings of the doubly-fed generator via another impedance. A direct current link of the rectifier is connected in parallel to a DC link of the converter. A controller  outputs an on-command to a power semiconductor switching element of the converter if a value of current flowing in the power semiconductor switching element is a predetermined value or larger.
 
−
|-valign="top"
 
−
|align = "center"|8
 
−
|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070132248%22.PGNR.&OS=DN/20070132248&RS=DN/20070132248 US20070132248]</u></font>
 
−
|align = "center"|06/14/07
 
−
|General Electric
 
−
|System and method of operating double fed induction generators
 
−
|Wind turbines with double fed induction generators are sensitive to grid faults. Conventional methods are not effective to reduce the shaft stress during grid faults and slow response and using dynamic voltage restorer (DVR) is cost expensive.
 
−
|The protection system has a controlled impedance device. Impedance device has bidirectional semiconductors such triac, assembly of thyristors or anti-parallel thyristors. Each of the controlled impedance devices is coupled between a respective phase of a stator winding of a double fed induction generator and a respective phase of a grid side converter. The protection system also includes a controller configured for coupling and decoupling impedance in one or more of the controlled impedance devices in response to changes in utility grid voltage and a utility grid current. High impedance is offered to the grid during network faults to isolate the dual fed wind turbine generator.
 
−
|-valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|9
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220060192390%22.PGNR.&OS=DN/20060192390&RS=DN/20060192390 US20060192390]</u></font>
 
−
|align = "center" bgcolor = "#DCE6F1"|08/31/06
 
−
|bgcolor = "#DCE6F1"|Gamesa Innovation
 
−
|bgcolor = "#DCE6F1"|Control and protection of a doubly-fed induction generator system
 
−
|bgcolor = "#DCE6F1"|AA short-circuit in the grid causes the generator to feed high stator-currents into the short-circuit and the rotor-currents increase very rapidly which cause damage to the power-electronic components of the converter connecting the rotor windings with the rotor-inverter.
 
−
|bgcolor = "#DCE6F1"|The converter is provided with a clamping unit which is triggered from a non-operation state to an operation state, during detection of over-current in the rotor windings. The clamping unit comprises passive voltage-dependent resistor element for providing a clamping voltage over the rotor windings when the clamping unit is triggered.
 
−
|-valign="top"
 
−
|align = "center"|10
 
−
|<font color="#0000FF"><u>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220050189896%22.PGNR.&OS=DN/20050189896&RS=DN/20050189896 US20050189896]</u></font>
 
−
|align = "center"|09/01/05
 
−
|ABB Research
 
−
|Method for controlling doubly-fed machine
 
−
|Controlling the double fed machines on the basis of inverter control to implement the targets set for the machine, this model is extremely complicated and includes numerous parameters that are often to be determined.
 
−
|A method is provided to use a standard scalar-controlled frequency converter for machine control. A frequency reference for the inverter with a control circuit, and reactive power reference are set for the machine. A rotor current compensation reference is set based on reactive power reference and reactive power. A scalar-controlled inverter is controlled for producing voltage for the rotor of the machine, based on the set frequency reference and rotor current compensation reference.
 
−
|-
 
 
|}
 
|}
−
Click '''[[Media:Doublyfed_induction_generator1.xls| here]]''' to view the detailed analysis sheet for doubly-fed induction generators patent analysis.
+
Source:[http://www.uni-hildesheim.de/~irwin/inside_wind_turbines.html Inside wind turbines]<br><br>
 +
<span style="color: rgb(46, 48, 255);">''In this report, a comprehensive analysis of patent and non-patent literature is done with a focus on Doubly-fed induction generator systems.'' </span>
 +
 
 +
=Wind Turbine Control Systems=
 +
As the wind turbines increases in size and power, control systems plays a major role to operate wind turbines in safe region and also to improve efficiency and quality of power conversion. The main objectives of wind turbine control systems is
 +
*''Energy capture'' : Operating the wind turbine to extract maximum amount of energy considering safe restrictions like rated power, rated speed, cut-out wind speed etc.,
 +
* ''Mechanical loads'': protecting the systems from transient loads.
 +
* ''Power quality'': Conditioning the generated power with grid interconnection standards.
 +
The various control techniques used in wind turbines are shown in table below
  
−
===Article Analysis===
 
 
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 
{|border="2" cellspacing="0" cellpadding="4" width="100%"
−
|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S No.'''</font>
+
|align = "center" bgcolor = "#83caff"|'''Control System'''
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Title'''</font>
+
|align = "center" bgcolor = "#83caff"|'''Pitch contol'''
−
|align = "center" bgcolor = "#4F81BD" width="105"|<font color="#FFFFFF">'''Publication Date<br>'''(mm/dd/yyyy)</font>
+
|align = "center" bgcolor = "#83caff"|'''Yaw control'''
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Journal/Conference'''</font>
+
|align = "center" bgcolor = "#83caff"|'''Stall control'''
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Dolcera Summary'''</font>
+
|align = "center" bgcolor = "#83caff"|'''Generator torque control'''
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|1
+
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/search/freesrchabstract.jsp?tp=&arnumber=1709031&queryText=Study+on+the+Control+of+DFIG+and+Its+Responses+to+Grid+Disturbances&openedRefinements=*&searchField=Search+All Study on the Control of DFIG and its Responses to Grid Disturbances ]</u></font>
+
−
|align = "center" bgcolor = "#DCE6F1"|01/01/06
+
−
|bgcolor = "#DCE6F1"|Power Engineering Society General Meeting, 2006. IEEE
+
−
|bgcolor = "#DCE6F1"|Presented dynamic model of the DFIG, including mechanical model, generator model, and PWM voltage source converters. Vector control strategies adapted for both the RSC and GSC to control speed and reactive power independently. Control designing methods, such as pole-placement method and the internal model control are used. MATLAB/Simulink is used for simulation.
+
−
|-valign="top"
+
−
|align = "center"|2
+
−
|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/search/freesrchabstract.jsp?tp=&arnumber=1649950&queryText=Application+of+Matrix+Converter+for+Variable+Speed+Wind+Turbine+Driving+an+Doubly+Fed+Induction+Generator&openedRefinements=*&searchField=Search+All Application of Matrix Converter for Variable Speed Wind Turbine Driving an Doubly Fed Induction Generator ]</u></font>
+
−
|align = "center"|05/23/06
+
−
|Power Electronics, Electrical Drives, Automation and Motion, 2006. SPEEDAM 2006.
+
−
|A matrix converter is replaced with back to back converter in a variable speed wind turbine using doubly fed induction generator. Stable operation is achieved by stator flux oriented control technique and the system operated in both sub and super synchronous modes, achieved good results.
+
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|3
+
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/search/freesrchabstract.jsp?tp=&arnumber=4778305&queryText=Optimal+Power+Control+Strategy+of+Maximizing+Wind+Energy+Tracking+and+Conversion+for+VSCF+Doubly+Fed+Induction+Generator+System&openedRefinements=*&searchField=Search+Al Optimal Power Control Strategy of Maximizing Wind Energy Tracking and Conversion for VSCF Doubly Fed Induction Generator System ]</u></font>
+
−
|align = "center" bgcolor = "#DCE6F1"|08/14/06
+
−
|bgcolor = "#DCE6F1"|Power Electronics and Motion Control Conference, 2006. IPEMC 2006. CES/IEEE 5th International
+
−
|bgcolor = "#DCE6F1"|Proposed a new optimal control strategy of maximum wind power extraction strategies and testified by simulation. The control algorithm also used to minimize the losses in the generator. The dual passage excitation control strategy is applied to decouple the active and reactive powers. With this control system, the simulation results show the good robustness and high generator efficiency is achieved.
+
−
|-valign="top"
+
−
|align = "center"|4
+
−
|<font color="#0000FF"><u>[http://docs.google.com/viewer?a=v&q=cache:HqaFsMBhchcJ:iris.elf.stuba.sk/JEEEC/data/pdf/3_108-8.pdf+A+TORQUE+TRACKING+CONTROL+ALGORITHM+FOR+DOUBLY–FED+INDUCTION+GENERATOR&hl=enπd=bl&srcid=ADGEESgbHXoAbKe4O7b5DnykDc7h_LaHwCMIhkVrGX_whx4iUuE4Mc-3Rfq1DyW_h A Torque Tracking Control algorithm for Doubly–fed Induction Generator ]</u></font>
+
−
|align = "center"|01/01/08
+
−
|Journal of Electrical Engineering
+
−
|Proposed a torque tracking control algorithm for Doubly fed induction generator using PI controllers. It is achieved by controlling the rotor currents and using a stator voltage vector reference frame.
+
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|5
+
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/search/freesrchabstract.jsp?tp=&arnumber=4651578&queryText=Fault+Ride+Through+Capability+Improvement+Of+Wind+Farms+Usind+Doubly+Fed+Induciton+Generator&openedRefinements=*&searchField=Search+All Fault Ride Through Capability Improvement Of Wind Farms Using Doubly Fed Induction Generator ]</u></font>
+
−
|align = "center" bgcolor = "#DCE6F1"|09/04/08
+
−
|bgcolor = "#DCE6F1"|Universities Power Engineering Conference, 2008. UPEC 2008. 43rd International
+
−
|bgcolor = "#DCE6F1"|An active diode bridge crowbar switch presented to improve fault ride through capability of DIFG. Showed different parameters related to crowbar such a crowbar resistance, power loss, temperature and time delay for deactivation during fault.
+
 
|-
 
|-
−
|}
+
|rowspan="2" align = "center" bgcolor = "#83caff"|'''Description'''
−
Click '''[[Media:Doublyfed_induction_generators1.xls| here]]''' to view the detailed analysis sheet for doubly-fed induction generators article analysis.
+
|A method of controlling the speed of a wind turbine by varying the orientation, or pitch, of the blades, and thereby altering its aerodynamics and efficiency.
−
<br>
+
Source:[http://www.moog.com/markets/energy/wind-turbines/blade-pitch-control/ Blade Pitch Control]
−
===Top Cited Patents===
+
|The rotation of horizontal axis wind turbine around its tower to orient the turbine in upwind or down wind direction.
−
{|border="2" cellspacing="0" cellpadding="4" width="100%"
+
Source:[http://zone.ni.com/devzone/cda/tut/p/id/8189 Wind Turbine Control Methods]
−
|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S. No.'''</font>
+
|Stall control works by increasing the angle at which the relative wind strikes the blades (angle of attack). As the wind speed increases drag force on the blade increase and lift force gets reduces, thus finally reduces the speed of turbine.A fully stalled turbine blade, when stopped, has the flat side of the blade facing directly into the wind. Compare with furling.
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Patent/Publication No.'''</font>
+
Source:[http://www.windmeup.org/2008/03/stall-control-basics.html Stall-control basics]
−
|align = "center" bgcolor = "#4F81BD" width="105"|<font color="#FFFFFF">'''Publication Date'''<br>(mm/dd/yyyy)</font>
+
|As the aerodynamic torque control changes, rotor speed changes. it changes the output power frequency. A frequency converter is connected in between generator and the network to maintain generator power constant.
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Assignee/Applicant'''</font>
+
Source[[Media:windenergycontrol.pdf|Wind Energy Control]]
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Title'''</font>
+
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Citation Count'''</font>
+
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|1
+
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5289041.PN.&OS=PN/5289041&RS=PN/5289041 US5289041]</u></font>
+
−
|align = "center" bgcolor = "#DCE6F1"|02/22/94
+
−
|bgcolor = "#DCE6F1"|US Windpower
+
−
|bgcolor = "#DCE6F1"|Speed control system for a variable speed wind turbine
+
−
|align = "center" bgcolor = "#DCE6F1"|80
+
−
|-valign="top"
+
−
|align = "center"|2
+
−
|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4982147.PN.&OS=PN/4982147&RS=PN/4982147 US4982147]</u></font>
+
−
|align = "center"|01/01/91
+
−
|Oregon State
+
−
|Power factor motor control system
+
−
|align = "center"|62
+
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|3
+
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5028804.PN.&OS=PN/5028804&RS=PN/5028804 US5028804]</u></font>
+
−
|align = "center" bgcolor = "#DCE6F1"|07/02/91
+
−
|bgcolor = "#DCE6F1"|Oregon State
+
−
|bgcolor = "#DCE6F1"|Brushless doubly-fed generator control system
+
−
|align = "center" bgcolor = "#DCE6F1"|51
+
−
|-valign="top"
+
−
|align = "center"|4
+
−
|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=5239251.PN.&OS=PN/5239251&RS=PN/5239251 US5239251]</u></font>
+
−
|align = "center"|08/24/93
+
−
|Oregon State
+
−
|Brushless doubly-fed motor control system
+
−
|align = "center"|49
+
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|5
+
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=6856038.PN.&OS=PN/6856038&RS=PN/6856038 US6856038]</u></font>
+
−
|align = "center" bgcolor = "#DCE6F1"|02/15/05
+
−
|bgcolor = "#DCE6F1"|Vestas Wind Systems
+
−
|bgcolor = "#DCE6F1"|Variable speed wind turbine having a matrix converter
+
−
|align = "center" bgcolor = "#DCE6F1"|43
+
−
|-valign="top"
+
−
|align = "center"|6
+
−
|<font color="#0000FF"><u>[http://www.wipo.int/pctdb/en/wo.jsp?WO=1999029034 WO1999029034]</u></font>
+
−
|align = "center"|06/10/99
+
−
|Asea Brown
+
−
|A method and a system for speed control of a rotating electrical machine with flux composed of two quantities
+
−
|align = "center"|36
+
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|7
+
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.wipo.int/pctdb/en/wo.jsp?WO=1999019963 WO1999019963]</u></font>
+
−
|align = "center" bgcolor = "#DCE6F1"|04/22/99
+
−
|bgcolor = "#DCE6F1"|Asea Brown
+
−
|bgcolor = "#DCE6F1"|Rotating electric machine
+
−
|align = "center" bgcolor = "#DCE6F1"|36
+
−
|-valign="top"
+
−
|align = "center"|8
+
−
|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7015595.PN.&OS=PN/7015595&RS=PN/7015595 US7015595]</u></font>
+
−
|align = "center"|03/21/06
+
−
|Vestas Wind Systems
+
−
|Variable speed wind turbine having a passive grid side rectifier with scalar power control and dependent pitch control
+
−
|align = "center"|34
+
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|9
+
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4763058.PN.&OS=PN/4763058&RS=PN/4763058 US4763058]</u></font>
+
−
|align = "center" bgcolor = "#DCE6F1"|08/09/88
+
−
|bgcolor = "#DCE6F1"|Siemens
+
−
|bgcolor = "#DCE6F1"|Method and apparatus for determining the flux angle of rotating field machine or for position-oriented operation of the machine
+
−
|align = "center" bgcolor = "#DCE6F1"|32
+
−
|-valign="top"
+
−
|align = "center"|10
+
−
|<font color="#0000FF"><u>[http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7095131.PN.&OS=PN/7095131&RS=PN/7095131 US7095131]</u></font>
+
−
|align = "center"|08/22/06
+
−
|General Electric
+
−
|Variable speed wind turbine generator
+
−
|align = "center"|25
+
 
|-
 
|-
−
|}
+
|[[Image:pitch.jpg|thumb|center|175px|Fig 16(a) '''[http://zone.ni.com/devzone/cda/tut/p/id/8189 Pitch control]''']]
−
===Top Cited Articles===
+
|[[Image:Yaw.jpg|thumb|center|175px|Fig 16(b) '''[http://zone.ni.com/devzone/cda/tut/p/id/8189 Yaw control]''']]
−
{|border="2" cellspacing="0" cellpadding="4" width="100%"
+
|align="center"| NA
−
|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S. No.'''</font>
+
|align="center"| NA
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Title'''</font>
+
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Publication Date'''</font>
+
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Journal/Conference'''</font>
+
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Citations Count'''</font>
+
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|1
+
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumber=502360 Doubly fed induction generator using back-to-back PWM converters and its application to variable-speed wind-energy generation]</u></font>
+
−
|align = "center" bgcolor = "#DCE6F1"|May. 1996
+
−
|bgcolor = "#DCE6F1"|IEEE Proceedings Electric Power Applications
+
−
|align = "center" bgcolor = "#DCE6F1"|906
+
−
|-valign="top"
+
−
|align = "center"|2
+
−
|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumber=999610 Doubly fed induction generator systems for wind turbines]</u></font>
+
−
|align = "center"|May. 2002
+
−
|IEEE Industry Applications Magazine
+
−
|align = "center"|508
+
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|3
+
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumber=1198317 Dynamic modeling of doubly fed induction generator wind turbines]</u></font>
+
−
|align = "center" bgcolor = "#DCE6F1"|May. 2003
+
−
|bgcolor = "#DCE6F1"|IEEE Transactions on Power Systems
+
−
|align = "center" bgcolor = "#DCE6F1"|274
+
−
|-valign="top"
+
−
|align = "center"|4
+
−
|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1201089 Modeling and control of a wind turbine driven doubly fed induction generator]</u></font>
+
−
|align = "center"|Jun. 2003
+
−
|IEEE Transactions on Energy Conversion
+
−
|align = "center"|271
+
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|5
+
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/iel5/60/30892/01432858.pdf?arnumber=1432858 Ride through of wind turbines with doubly-fed induction generator during a voltage dip]</u></font>
+
−
|align = "center" bgcolor = "#DCE6F1"|Jun. 2005
+
−
|bgcolor = "#DCE6F1"|IEEE Transactions on Energy Conversion
+
−
|align = "center" bgcolor = "#DCE6F1"|246
+
−
|-valign="top"
+
−
|align = "center"|6
+
−
|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=970114 Dynamic modeling of a wind turbine with doubly fed induction generator]</u></font>
+
−
|align = "center"|July. 2001
+
−
|IEEE Power Engineering Society Summer Meeting, 2001
+
−
|align = "center"|196
+
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|7
+
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1597345 Modeling of the wind turbine with a doubly fed induction generator for grid integration studies]</u></font>
+
−
|align = "center" bgcolor = "#DCE6F1"|Mar. 2006
+
−
|bgcolor = "#DCE6F1"|IEEE Transactions on Energy Conversion
+
−
|align = "center" bgcolor = "#DCE6F1"|174
+
−
|-valign="top"
+
−
|align = "center"|8
+
−
|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumber=543631 A doubly fed induction generator using back-to-back PWM converters supplying an isolated load from a variable speed wind turbine]</u></font>
+
−
|align = "center"|Sept. 1996
+
−
|IEEE Proceedings Electric Power Applications
+
−
|align = "center"|150
+
−
|-valign="top"
+
−
|align = "center" bgcolor = "#DCE6F1"|9
+
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumber=1432853 Doubly fed induction generator model for transient stability analysis]</u></font>
+
−
|align = "center" bgcolor = "#DCE6F1"|Jun. 2005
+
−
|bgcolor = "#DCE6F1"|IEEE Transactions on Energy Conversion
+
−
|align = "center" bgcolor = "#DCE6F1"|106
+
−
|-valign="top"
+
−
|align = "center"|10
+
−
|<font color="#0000FF"><u>[http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1677655 Control of a doubly fed induction generator in a wind turbine during grid fault ride-through]</u></font>
+
−
|align = "center"|Sept. 2006
+
−
|IEEE Transactions on Energy Conversion
+
−
|align = "center"|112
+
 
|-
 
|-
 
|}
 
|}
  
−
= Dolcera Dashboard =
+
=Taxonomy for Wind Turbines=
−
[[Image:dashboard_features.png|center|750px|]]
+
A detailed taxonomy is presented which covers Parts, Types, Control Systems, Generating systems and Applications of wind turbines.
  
−
'''Dashboard Link'''<br>
+
[[Image:windTurbines12.jpeg|center|1000px]]
−
{|border="2" cellspacing="0" cellpadding="4" width="100%"
+
−
|'''[http://client.dolcera.com/dashboard/dashboard.html?workfile_id=825 Doubly Fed Induction Generator - Dashboard] '''
+
−
|width="100"|[[Image:dashboard_thumb.png|center|100px|]]
+
−
|-
+
−
|}
+
−
*Flash Player is essential to view the Dolcera dashboard
+
  
−
=Products=
 
−
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 
−
|align = "center" bgcolor = "#4F81BD" width=”38”|<font color="#FFFFFF">'''S. No.'''</font>
 
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Company'''</font>
 
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Product'''</font>
 
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Specifications'''</font>
 
−
|-valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|1
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.vestas.com/en/wind-power-plants/procurement/turbine-overview/v80-2.0-mw.aspx#/vestas-univers Vestas]</u></font>
 
−
|bgcolor = "#DCE6F1"|V80
 
−
|bgcolor = "#DCE6F1"|'''Rated Power: '''2.0 MW,  '''Frequency:''' 50 Hz/60 Hz, '''Number of Poles:''' 4-pole, '''Operating Temperature: -'''30°C to 40°
 
−
|- valign="top"
 
−
|align = "center"|2
 
−
|<font color="#0000FF"><u>[http://www.vestas.com/en/wind-power-plants/procurement/turbine-overview/v80-2.0-mw.aspx#/vestas-univers Vestas]</u></font>
 
−
|V90
 
−
|'''Rated Power:''' 1.8/2.0 MW, '''Frequency :''' 50 Hz/60 Hz, '''Number of Poles :''' 4-pole(50 Hz)/6-pole(60 Hz), '''Operating Temperature: -'''30°C to 40°
 
−
|- valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|3
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.vestas.com/en/wind-power-plants/procurement/turbine-overview/v80-2.0-mw.aspx#/vestas-univers Vestas]</u></font>
 
−
|bgcolor = "#DCE6F1"|V90 Offshore
 
−
|bgcolor = "#DCE6F1"|'''Rated Power:''' 3.0 MW, '''Frequency:''' 50 Hz/60 Hz, '''Number of Poles:''' 4-pole, '''Operating Temperature: '''-30°C to 40°
 
−
|- valign="top"
 
−
|align = "center"|4
 
−
|<font color="#0000FF"><u>[http://www.china-windturbine.com/news/doubly_wind_turbines.htm North Heavy Company]</u></font>
 
−
|2 MW DFIG
 
−
|'''Rated Power:''' 2.0 MW, '''Rated Voltage:''' 690V, '''Rated Current:''' 1670A, '''Frequency:''' 50Hz, '''Number of Poles :''' 4-pole,  '''Rotor Rated Voltage:''' 1840V, '''Rotor Rated Current''' 670A, '''Rated Speed:''' 1660rpm;''' Power Speed Range: '''520-1950 rpm, '''Insulation Class:''' H, '''Protection Class:''' IP54,  '''Motor Temperature Rise''' =<nowiki><</nowiki>95K
 
−
|- valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|5
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://docs.google.com/viewer?a=v&q=cache:X9KReq0YEigJ:www.iberdrolarenewables.us/bluecreek/docs/primary/03-Appendices/_Q-Brochure-of-G-90-Turbine/Brochure-G-90-Turbine.pdf+gamesa+g90&hl=en&pid=bl&srcid=ADGEESgldaLogi1i5Pg71zE-FO_AMqbeKL5wJiA8LVklgq5ev2in Gamesa]</u></font>
 
−
|bgcolor = "#DCE6F1"|G90
 
−
|bgcolor = "#DCE6F1"|'''Rated Voltage:''' 690 V,  '''Frequency:''' 50 Hz,  '''Number of Poles:''' 4,  '''Rotational Speed:''' 900:1,900 rpm (rated 1,680 rpm) (50Hz); '''Rated Stator Current: '''1,500 A @ 690 V, '''Protection Class:''' IP 54, '''Power Factor(standard):'''  0.98 CAP - 0.96 IND at partial loads and 1 at nominal power, '''Power Factor(Optional):''' 0.95 CAP - 0.95 IND throughout the power range
 
−
|- valign="top"
 
−
|align = "center"|6
 
−
|<font color="#0000FF"><u>[http://www.nordex-online.com/en/products-services/wind-turbines/n100-25-mw Nordex]</u></font>
 
−
| N80
 
−
|'''Rated Power:''' 2.5 MW, '''Rated Voltage:''' 690V, '''Frequency:''' 50/60Hz, '''Cooling Systems:''' liquid/air
 
−
|- valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|7
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.nordex-online.com/en/products-services/wind-turbines/n100-25-mw Nordex]</u></font>
 
−
|bgcolor = "#DCE6F1"| N90
 
−
|bgcolor = "#DCE6F1"|'''Rated Power:''' 2.5 MW, '''Rated Voltage: '''690V,''' Frequency: '''50/60Hz,''' Cooling Systems: '''liquid/air
 
−
|- valign="top"
 
−
|align = "center"|8
 
−
|<font color="#0000FF"><u>[http://www.nordex-online.com/en/products-services/wind-turbines/n100-25-mw Nordex]</u></font>
 
−
|N100
 
−
|'''Rated Power:''' 2.4 MW, '''Rated Voltage: '''690V, '''Frequency: '''50/60Hz, '''Cooling Systems: '''liquid/air
 
−
|- valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|9
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.nordex-online.com/en/products-services/wind-turbines/n100-25-mw Nordex]</u></font>
 
−
|bgcolor = "#DCE6F1"| N117
 
−
|bgcolor = "#DCE6F1"|'''Rated Power:''' 2.5 MW, '''Rated Voltage: '''690V, '''Frequency: '''50/60Hz, '''Cooling Systems: '''liquid/air
 
−
|- valign="top"
 
−
|align = "center"|10
 
−
|<font color="#0000FF"><u>[http://www.converteam.com/majic/pageServer/1704040148/en/index.html Converteam]</u></font>
 
−
|DFIG
 
−
|NA
 
−
|- valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|11
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://geoho.en.alibaba.com/product/252321923-0/1_5MW_doubly_fed_asynchronous_generator.html Xian Geoho Energy Technology]</u></font>
 
−
|bgcolor = "#DCE6F1"|1.5MW DFIG
 
−
|bgcolor = "#DCE6F1"|'''Rated Power:''' 1550KW,  '''Rated Voltage: '''690V, '''Rated Speed: '''1755 r/min, '''Speed Range: '''975<nowiki>~</nowiki>1970 r/min, '''Number of Poles: '''4-pole, '''Stator Rated Voltage: '''690V±10%, '''Stator Rated Current: '''1115A; '''Rotor Rated Voltage: '''320V, '''Rotor Rated Current: '''430A, '''Winding Connection: '''Y / Y, '''Power Factor: '''0.95(Lead) <nowiki>~</nowiki> 0.95Lag,''' Protection Class: '''IP54, '''Insulation Class: '''H, '''Work Mode: '''S1, '''Installation ModeI: '''M B3, '''Cooling Mode: '''Air cooling,  '''Weight: '''6950kg
 
−
|- valign="top"
 
−
|align = "center"|12
 
−
|<font color="#0000FF"><u>[http://www.tecowestinghouse.com/products/custom_engineered/DF_WR_ind_generator.html Tecowestinghouse]</u></font>
 
−
|TW450XX (0.5-1 KW)
 
−
|'''Rated Power:''' 0.5 -1 KW, '''Rated Voltage: '''460/ 575/ 690 V, '''Frequency: '''50/ 60 Hz, '''Number of Poles: '''4/6,''' Ambient Temp.(°C): -'''40 to 50, '''Speed Range (% of Synch. Speed): '''68% to 134%,  '''Power Factor (Leading): -'''0.90 to <nowiki>+</nowiki>0.90 , '''Insulation Class: '''H/F, '''Efficiency: '''<nowiki>></nowiki>= 96%
 
−
|- valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|13
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.tecowestinghouse.com/products/custom_engineered/DF_WR_ind_generator.html Tecowestinghouse]</u></font>
 
−
|bgcolor = "#DCE6F1"|TW500XX (1-2 KW)
 
−
|bgcolor = "#DCE6F1"|'''Rated Power:''' 1-2 kW,''' Rated Voltage:''' 460/ 575/ 690 V, '''Frequency:''' 50/ 60 Hz, '''Number of Poles:''' 4/6, Ambient Temp.(°C): -40 to 50; '''Speed Range (% of Synch. Speed):''' 68 to 134%, '''Power Factor(Leading): -'''0.90 to <nowiki>+</nowiki>0.90, '''Insulation Class: '''H/F, '''Efficiency:''' <nowiki>></nowiki>= 96%
 
−
|- valign="top"
 
−
|align = "center"|14
 
−
|<font color="#0000FF"><u>[http://www.tecowestinghouse.com/products/custom_engineered/DF_WR_ind_generator.html Tecowestinghouse]</u></font>
 
−
|TW560XX (2-3 KW)
 
−
|'''Rated Power: '''2-3kW, '''Rated Voltage: '''460/ 575/ 690 V, '''Frequency: '''50/ 60 Hz, '''Number of Poles: '''4/6, '''Ambient Temp(°C): ''' -40 to 50, '''Speed Range(% of Synch. Speed)''':''' '''68 to 134%, '''Power Factor(Leading):''' -0.90 to <nowiki>+</nowiki>0.90, '''Insulation Class: '''H/F, '''Efficiency:''' <nowiki>></nowiki>= 96%.
 
−
|- valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|15
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.acciona-na.com/About-Us/Our-Projects/U-S-/West-Branch-Wind-Turbine-Generator-Assembly-Plant.aspx Acciona]</u></font>
 
−
|bgcolor = "#DCE6F1"|AW1500
 
−
|bgcolor = "#DCE6F1"|'''Rated Power:''' 1.5MW, '''Rated Voltage: '''690 V, '''Frequency: '''50 Hz, '''Number of Poles: '''4,  '''Rotational Speed: '''900:1,900 rpm(rated 1,680 rpm) (50Hz), '''Rated Stator Current: '''1,500 A @ 690 V, '''Protection Class: '''IP54, '''Power Factor(standard): '''0.98 CAP - 0.96 IND at partial loads and 1 at nominal power, '''Power factor(optional):''' 0.95 CAP - 0.95 IND throughout the power range
 
−
|- valign="top"
 
−
|align = "center"|16
 
−
|<font color="#0000FF"><u>[http://www.acciona-na.com/About-Us/Our-Projects/U-S-/West-Branch-Wind-Turbine-Generator-Assembly-Plant.aspx Acciona]</u></font>
 
−
|AW3000
 
−
|'''Rated Power:''' 3.0MW, '''Rated Voltage: ''' 690 V, '''Frequency: '''50 Hz, '''Number of Poles: '''4, '''Rotational Speed: '''900:1,900 rpm(rated 1,680 rpm) (50Hz), '''Rated Stator Current: '''1,500 A @ 690 V, '''Protection Class: '''IP54, '''Power Factor(standard): '''0.98 CAP - 0.96 IND at partial loads and 1 at nominal power, '''Power Factor (optional):''' 0.95 CAP - 0.95 IND throughout the power range
 
−
|- valign="top"
 
−
|align = "center" bgcolor = "#DCE6F1"|17
 
−
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://gepower.com/businesses/ge_wind_energy/en/index.htm General Electric]</u></font>
 
−
|bgcolor = "#DCE6F1"|GE 1.5/2.5MW
 
−
|bgcolor = "#DCE6F1"|'''Rated Power:''' 1.5/2.5 MW, '''Frequency(Hz): '''50/60
 
−
|-
 
−
|}
 
  
−
=Market Research=
+
==IPC Classifications==
−
==Major Players==
+
A majority of patents describing wind turbines or wind energy are classified in the following IPC classifications.  
−
Vestas Wind Systems, General Electric and Gamesa Innovation & Technology are the top players in terms of installed power capacity in the year 2007.
+
 
{|border="2" cellspacing="0" cellpadding="4" width="100%"
 
{|border="2" cellspacing="0" cellpadding="4" width="100%"
−
|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">'''S.No.'''</font>
+
| align = "center" bgcolor = "#99ccff"|'''S.NO'''
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Company'''</font>
+
| align = "center" bgcolor = "#99ccff"|'''IPC Classification'''
−
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Installed Capacity'''(MW)</font>
+
| align = "center" bgcolor = "#99ccff"|'''Description'''
 
|-
 
|-
−
|align = "center" bgcolor = "#DCE6F1"|1
+
| align = "center" bgcolor = "#99ccff"|1
−
|bgcolor = "#DCE6F1"|Vestas (Denmark)
+
| align = "center"|[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=F03D F03D]
−
|align = "right" bgcolor = "#DCE6F1"|4,500
+
| WIND MOTORS
 
|-
 
|-
−
|align = "center"|2
+
| align = "center" bgcolor = "#99ccff"|2
−
|GE Energy (United States)
+
| align = "center"|[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=F16C F16C]
−
|align = "right"|3,300
+
| SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OF CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
 
|-
 
|-
−
|align = "center" bgcolor = "#DCE6F1"|3
+
| align = "center" bgcolor = "#99ccff"|3
−
|bgcolor = "#DCE6F1"|Gamesa (Spain)
+
| align = "center"|[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=F16H F16H]
−
|align = "right" bgcolor = "#DCE6F1"|3,050
+
| GEARING
 
|-
 
|-
−
|align = "center"|4
+
| align = "center" bgcolor = "#99ccff"|4
−
|Enercon (Germany)
+
| align = "center"|[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=F03B F03B]
−
|align = "right"|2,700
+
| MACHINES OR ENGINES FOR LIQUIDS
 
|-
 
|-
−
|align = "center" bgcolor = "#DCE6F1"|5
+
|align = "center" bgcolor = "#99ccff"|5
−
|bgcolor = "#DCE6F1"|Suzlon (India)
+
|align = "center"|[http://www.wipo.int/ipcpub/#refresh=symbol&notion=scheme&version=20110101&symbol=H02K H02K]
−
|align = "right" bgcolor = "#DCE6F1"|2,000
+
|DYNAMO-ELECTRIC MACHINES
 
|-
 
|-
−
|align = "center"|6
+
| align = "center" bgcolor = "#99ccff"|6
−
|Siemens (Denmark/Germany)
+
| align = "center"|[http://www.wipo.int/ipcpub/#&refresh=page&notion=scheme&version=20110101&symbol=H02P H02P]
−
|align = "right"|1,400
+
| CONTROL OR REGULATION OF ELECTRIC MOTORS, GENERATORS, OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
 
|-
 
|-
−
|align = "center" bgcolor = "#DCE6F1"|7
+
| align = "center" bgcolor = "#99ccff"|7
−
|bgcolor = "#DCE6F1"|Acciona (Spain)
+
| align = "center"|[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=H02M H02M]
−
|align = "right" bgcolor = "#DCE6F1"|870
+
| APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION
 
|-
 
|-
−
|align = "center"|8
+
| align = "center" bgcolor = "#99ccff"|8
−
|Goldwind (China - PRC)
+
| align = "center"|[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=H02J H02J]
−
|align = "right"|830
+
| CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
 
|-
 
|-
−
|align = "center" bgcolor = "#DCE6F1"|9
+
| align = "center" bgcolor = "#99ccff"|9
−
|bgcolor = "#DCE6F1"|Nordex (Germany)
+
| align = "center"|[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=G06F G06F]
−
|align = "right" bgcolor = "#DCE6F1"|670
+
| ELECTRIC DIGITAL DATA PROCESSING
 
|-
 
|-
−
|align = "center"|10
+
| align = "center" bgcolor = "#99ccff"|10
−
|Sinovel (China - PRC)
+
| align = "center"|[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=G05F G05F]
−
|align = "right"|670
+
| SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
 
|-
 
|-
 +
| align = "center" bgcolor = "#99ccff"|11
 +
| align = "center"|[http://www.wipo.int/ipcpub/#refresh=page&notion=scheme&version=20110101&symbol=H02H H02H]
 +
| EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
 
|}
 
|}
  
−
Source:[http://www.mywindpowersystem.com/2009/04/the-10-major-wind-power-companies-in-the-world/ Wind power companies]
+
== Major Players==
−
 
+
Major players in the Wind Energy sector include: General Electric, Vestas Wind Systems, Siemens AG, Mitsubishi Ltd, REPower Systems AG, Gamesa Innovation & Technology, Enercon, Nordex, Suzlon and Sinovel Wind Group Co. Ltd.
−
==Market Overview==
+
−
* The world's wind industry defied the economic downturn in 2008 and by he end of the year 2009, the sector saw its annual market grow by 41.5% over 2008, and total global wind power capacity increased by 31.7% to 158GW in 2009.
+
−
* US, China and Germany together hold more than 50% of the global wind power capacity.
+
−
* Asia and North America have seen tremendous growth in the installed wind power capacity over the last 6 years.
+
−
* Asia was the world's largest regional market for wind energy with capacity additions amounting to 15.4GW. China was the world's largest market in 2009, more than doubling its capacity from 12.1GW in 2008 to 25.8GW, adding a staggering 13.8GW of capacity.
+
−
* China and the US account for more than 60% of the new installed capacity of 38.3GW in 2009. India's total installed capacity increased to 10.9GW with 1.3GW of new installed capacity in 2009.
+
−
* The 2009 market for turbine installations was worth about 45 bn € or 63 bn US$ and about half a million people are now employed by the wind industry around  the world.
+
−
{|border="0" cellspacing="0" cellpadding="4" width="100%"
+
−
|[[Image:wind energy Installed capacity1 2009.png|center|thumb|Top 10 Cumulative Installed Capacity 2009]]
+
−
|[[Image:wind energy New capacity1.png|center|thumb|Top 10 New Installed Capacity 2009]]
+
−
|-
+
−
|}
+
−
[[Image:Region Capacities.png|600px|center|thumb|Annual Installed Capacity by Region 2003-2009]]
+
−
 
+
−
==Market Forecast==
+
−
* Global wind power capacity could reach 2,300 GW by 2030, providing up to 22% of the world's electricity needs, from the existing 2.2% in 2010.
+
−
* Global wind capacity will stand at 409GW up from 158GW at the end of 2008. During 2014, 62.5 GW of new capacity will be added to the global total, compared to 38.3 GW in 2009
+
−
* The annual growth rates during this period will average 20.9% in terms of total installed capacity, and 10.3% for annual market growth
+
−
* Three regions will continue to drive the expansion of wind energy capacity: Asia, North America and Europe
+
−
* Asia will remain the fastest growing market in the world, driven primarily by China, which is set to continue the rapid upscaling of its wind capacity and hold its position as the world’s largest annual market. Annual additions are expected to be well over 20 GW in China by 2014
+
−
* Sustained growth is also expected in India, which will increase its capacity steadily by 2 GW every year, and be complemented by growth in other Asian markets, including Japan, Taiwan, South Korea and the Philippines, and potentially some others
+
−
* By 2014, the annual market will reach 14.5 GW, and a total of 60 GW will be installed in Europe over this five year period
+
−
[[Image:Market forecast.png|800px|center|thumb|ANNUAL MARKET FORECAST BY REGION 2009-2013]]
+
−
<br>
+
−
Source:[http://www.gwec.net/index.php?id=167 GWEC's Global Wind Report 2009]
+
−
 
+
−
=Insights=
+
−
== Major Players ==
+
−
* [http://www.vestas.com/ Vestas Wind Energy Systems] and [http://www.ge.com/ General Electric] are the major players in wind energy generation technology.
+
−
[[Image:wind_major_players.png|center|thumb|700px|'''Major Players''']]
+
−
 
+
−
== Key Patents ==
+
−
* The key patents in the field are held by [http://www.windpoweringamerica.gov/wind_installed_capacity.asp US Windpower], [http://www.oregon.gov/ENERGY/RENEW/Wind/windhome.shtml Oregon State] and [http://www.vestas.com/ Vestas Wind Energy Systems].
+
−
 
+
−
[[Image:wind_top_cited.png|center|thumb|700px|'''Key Patents''']]
+
−
 
+
−
== IP Activity ==
+
−
* Patenting activity has seen a very high growth rate in the last two years.
+
−
[[Image:ind_pat_act_3.png|center|thumb|700px|'''Year wise IP Activity''']]
+
−
 
+
−
== Geographical Activity ==
+
−
* USA, China, Germany, Spain, and India are very active in wind energy research.
+
−
[[Image:wind_geographical_act.png|center|thumb|700px|'''Geographical Activity''']]
+
−
 
+
−
== Research Trend ==
+
−
* Around 86% patents are on controlling the doubly-fed induction generation(DFIG) which indicates high research activity going on in rating and controlling of the DFIG systems.
+
−
 
+
−
== Issues in the Technology ==
+
−
* 86% of the patent on DFIG operation are focusing on grid connected mode of operation, suggesting continuous operation of the DFIG system during weak and storm winds, grid voltage sags, and grid faults are major issues in the current scenario.
+
−
 
+
−
== Emerging Player ==
+
−
* [http://www.woodward.com/ Woodward] is a new and fast developing player in the field of DFIG technology. The company filed 10 patent applications in the field in year 2010, while it has no prior IP activity.
+
  
 
=<span style="color:#C41E3A">Like this report?</span>=
 
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! style="background:lightgrey" | Samir Raiyani
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| style="background-color:#999990;padding:0.079cm;"| <center>[http://dolcera.com/wiki/index.php?title=Wind_Energy <<Back to main page]</center>
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|-
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| '''Email''': [mailto:info@dolcera.com info@dolcera.com]
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| '''Phone''': +1-650-269-7952
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|}
 
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Revision as of 05:09, 17 March 2011

Brief History of Wind Energy

Although the use of wind power started around 5000 BC, but electric power generation through wind energy started in 18th century and increasing drastically in 19th and 20th centuries. A brief view on developments on wind power sector are listed below.

Fig 1 Development of wind power worldwide
  • 1887  : Prof. James Blyth of Scotland used windmills for generating electricity.
  • 1888  : Charles Brush developed the first wind-powered turbine that generated electricity in the United States based on emulated James Blyth work.
  • 1927  : Joe Jacobs and Marcellus Jacobs improved the wind turbine generator for use in farms.
  • 1931 : development of Darrieus wind turbine. It is a vertical axis turbine that rotates with wind from any direction.
  • 1941: Largest mega watt range wind turbine was connected to the local electrical distribution system on the mountain known as Grandpa's Knob in Castleton, Vermont, USA.
  • 1971: Denmark installed the first offshore wind farms
  • 1990s: More than 2200 MW capacity of wind turbines are installed in california.
  • 2003: the largest offshore wind farm North Hoyle was built in the United Kingdom.
  • 2003-2010: Research is going is on wind turbines in blades structures, generators, operation and protection, efficiency of wind turbines.

Source: Wind Energy
The total installed wind power capacity from 2001 to 2010 is shown in fig. 1. All wind turbines installed by the end of year 2009 worldwide are generating 340 TWh per annum. The country wise share of wind energy by the end of year 2009 is shown in fig. 2.

Fig 2 Country share of total capacity

Working Principle of Wind Turbine

Wind is air in motion. It is a form of solar energy. Solar radiation heats every part of the Earth’s surface unevenly due to irregularities and rotation of earth. The flow of wind patterns are modified by the earth's terrain, bodies of water, and vegetative cover. When air moves, causing wind, it has kinetic energy. The kinetic energy of wind can be captured by a wind turbine and converted to other forms of energy such as electricity or mechanical power.

Fig 3 Wind turbine principle

Sources:Wind Energy Basics,How Wind Turbines Work

Horizontal Axis and Vertical Axis Wind Turbines

Wind turbines are mainly classified into two types based on the axis in which turbine rotates. They are Horizontal axis wind turbine(HAWT) and vertical axis wind turbine (VAWT). The table below presented, describes the advantages and disadvantages of HAWT's and VAWT's.

Horizontal axis wind turbines Vertical axis wind turbines
  • It is mounted on top of a tower ,requires huge towers leads to complex in operation, maintenance and high initial costs.
  • It operates only with upstream or down stream wind directions.
  • It can be constructed in off-shores.
  • It produces large amount of electricity with high efficiency.
  • These are easy to build and maintain, safer, easier to transport and they can be mounted close to the ground.
  • These can handle much turbulence in wind than horizontal wind turbines.
  • Mostly it can be constructed with two blades
  • It operates with any direction of wind
  • Production of electricity is less due to low wind speeds near to ground
Fig 4(a)Horizontal axis wind turbine
Fig 4(b)Vertical axis wind turbine

Source:Different types of wind turbines

Horizontal Axis Wind Turbines

HWAT1.PNG


All grid-connected commercial wind turbines today are built with a horizontal axis type rotor which is installed on top of a tower. Most horizontal axis turbines built today are two- or three-bladed, although some have fewer or more blades. The purpose of the rotor is to convert the linear motion of the wind into rotational energy that can be used to drive a generator. Most of the systems have a gearbox, which turns the slow rotation of the blades into a quicker rotation that is more suitable to drive an electrical generator.

Click on the link below to see detailed description about horizontal axis wind turbines.
Different Types and Parts of a Horizontal Axis Wind Turbines

Electrical Generating Systems

The various types of electrical generating systems used in wind energy systems are shown in figure.

Generator.png

Source:Wind Turbine Generators

The most commonly used generator systems applied in wind turbines are are explained below.

Fixed speed generating systems Variable speed generating systems Doubly fed induction generator
Structure
Fixed.png
Variable.png
Dfigg.png
Machines SQIG PMSG/WRSG/WRIG DFIG
Advantages * Simple and low cost

* Low maintenance

* Complete control of real and reactive powers

* High energy efficiency

* Reduced capacity converter

* Decoupled control of active and reactive power flow

* Smooth grid connection

Drawbacks * No control on real and reactive power

* Less optimum power extraction capability

* Poor power factor

* High mechanical stress on turbine mechanical components

* Additional cost of power electronics

* Limited fault ride through capability

* Regular maintenance of slip ring and gearbox

* Limited fault ride-through capability

Source:Inside wind turbines

In this report, a comprehensive analysis of patent and non-patent literature is done with a focus on Doubly-fed induction generator systems.

Wind Turbine Control Systems

As the wind turbines increases in size and power, control systems plays a major role to operate wind turbines in safe region and also to improve efficiency and quality of power conversion. The main objectives of wind turbine control systems is

  • Energy capture : Operating the wind turbine to extract maximum amount of energy considering safe restrictions like rated power, rated speed, cut-out wind speed etc.,
  • Mechanical loads: protecting the systems from transient loads.
  • Power quality: Conditioning the generated power with grid interconnection standards.

The various control techniques used in wind turbines are shown in table below

Control System Pitch contol Yaw control Stall control Generator torque control
Description A method of controlling the speed of a wind turbine by varying the orientation, or pitch, of the blades, and thereby altering its aerodynamics and efficiency.

Source:Blade Pitch Control

The rotation of horizontal axis wind turbine around its tower to orient the turbine in upwind or down wind direction.

Source:Wind Turbine Control Methods

Stall control works by increasing the angle at which the relative wind strikes the blades (angle of attack). As the wind speed increases drag force on the blade increase and lift force gets reduces, thus finally reduces the speed of turbine.A fully stalled turbine blade, when stopped, has the flat side of the blade facing directly into the wind. Compare with furling.

Source:Stall-control basics

As the aerodynamic torque control changes, rotor speed changes. it changes the output power frequency. A frequency converter is connected in between generator and the network to maintain generator power constant.

SourceWind Energy Control

Fig 16(a) Pitch control
Fig 16(b) Yaw control
 NA NA

Taxonomy for Wind Turbines

A detailed taxonomy is presented which covers Parts, Types, Control Systems, Generating systems and Applications of wind turbines.

WindTurbines12.jpeg


IPC Classifications

A majority of patents describing wind turbines or wind energy are classified in the following IPC classifications.

S.NO IPC Classification Description
1 F03D WIND MOTORS
2 F16C SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OF CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
3 F16H GEARING
4 F03B MACHINES OR ENGINES FOR LIQUIDS
5 H02K DYNAMO-ELECTRIC MACHINES
6 H02P CONTROL OR REGULATION OF ELECTRIC MOTORS, GENERATORS, OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
7 H02M APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION
8 H02J CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
9 G06F ELECTRIC DIGITAL DATA PROCESSING
10 G05F SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
11 H02H EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS

Major Players

Major players in the Wind Energy sector include: General Electric, Vestas Wind Systems, Siemens AG, Mitsubishi Ltd, REPower Systems AG, Gamesa Innovation & Technology, Enercon, Nordex, Suzlon and Sinovel Wind Group Co. Ltd.

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