'''Summary'''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.[[Image:Wind_Flowchart.PNG|right|580px|thumb|Process Flow]]
This report presents a brief summary about wind energy and present day 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 focus on '''Doubly-fed Induction Generator (DFIG)''' used in the horizontal axis wind turbines for efficient power generation. Existing products' information of major players in the market is also compiled for Doubly-fed induction generators. Existing market and future market prediction for wind energy based power generation is presented.
<br>
'''Insights'''
* USA, China, Germany, Spain and India share major part of wind energy generation in the year 2010.
* Vestas Wind Energy Systems and General Electric are the major players in wind energy generation technology.
* Patenting activity has seen high growth rate in the years 2009 and 2010.
* Research activity mainly going on rating and controlling of the Doubly-fed induction generation systems. Out of 139 patents 120 patents are discussing about controlling the DFIG.
* Continuous Operation of the DFIG system during weak and storm winds, grid voltage sags, and grid faults are major issues in current scenario. Among 28 patents covering DFIG operation, 24 patents are focusing on grid connected mode of operation.
* [http://www.woodward.com/ Woodward GMBH] is a new and fast developing player in the field of DFIG technology,and filed 10 patent applications in the field in year 2010, while it has no prior IP activity.<br><br><br>
=Introduction=
* Humans We have been using wind power for 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.
* 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.
* 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> == Read More? ==Click on '''[[Wind Energy Background]]''' to read more about wind energy.
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.
= DoublyFor variable-fed Induction Generator=The present study on the IP activity in the area of horizontal axis wind turbines speed systems with focus on '''''Doublylimited variable-speed range, e.g. ±30% of synchronous speed, the doubly-fed Induction Generator induction generator(DFIG)''''' can be an interesting solution. This is based on mainly due to the fact that the power electronic converter only has to handle a search conducted on Thomson Innovationfraction (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. ==Control patents==
{|border="2" cellspacingMarket Research="0" cellpadding="5" width="100%"|bgcolor = "#99ccff"| <center>'''S No'''</center>|bgcolor = "#99ccff"| <center>'''Patent / Publication No.'''</center>|bgcolor The History of Wind Energy= "#99ccff"| <center>'''Publication Date'''</center>|bgcolor = "#99ccff"| <center>'''Assignee / Applicant'''</center>|bgcolor = "#99ccff"| <center>'''Title'''</center>
|-| style="background-color:#99ccff"| <center>To read about '''1the History of Wind Energy''', '''</center>| <center>[http://patftdolcera.uspto.govcom/netacgiwiki/nph-Parserindex.php?Sect1title=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 US6278211B1The_History_of_Wind_Energy click here]</center>| <center>02/08/01</center>| <center>SWEO EDWIN A</center>| Brushless doubly-fed induction machines employing dual cage rotors'''
|-==Global Wind Energy Market==| style="background-color:#99ccff"| <center>==Market Overview===* In the year 2010, the wind capacity reached worldwide '''2196’630 Megawatt'''</center>, after '''159’050 MW''' in 2009, '''120’903 MW''' in 2008, and '''93’930 MW''' in 2007.[[Image:World_Installed2.PNG| <center>|600px|thumb|Source: [http://patftwww.usptowwindea.govorg/netacgihome/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=images/stories/pdfs/worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]]]* Wind power showed a growth rate of '''23.6 %2Fnetahtml%2FPTO%2Fsrchnum''', the lowest growth since 2004 and the second lowest growth of the past decade.htm&r=1&f=G&l=50&s1=6954004* For the first time in more than two decades, the market for new wind turbines was smaller than in the previous year and reached an overall size of '''37’642 MW''', after 38'312 MW in 2009.PN[[Image:New.&OS=PNPNG|center|600px|thumb|Source: [http:/6954004&RS=PN/6954004 US6954004B2]<www.wwindea.org/center>| <center>11home/10images/05<stories/center>pdfs/worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]]]| <* All wind turbines installed by the end of 2010 worldwide can generate '''430 Tera watt hours per annum''', more than the total electricity demand of the United Kingdom, the sixth largest economy of the world, and equaling 2.5 % of the global electricity consumption.* In the year 2010, altogether '''83 countries''', one more than in 2009, used wind energy for electricity generation. 52 countries increased their total installed capacity, after 49 in the previous year.* The turnover of the wind sector worldwide reached '''40 billion Euros (55 billion US$) in 2010''', after 50 billion Euros (70 billion US$) in the year 2009. The decrease is due to lower prices for wind turbines and a shift towards China.* China became number one in total installed capacity and the center>SPELLMAN HIGH VOLTAGE ELECTRON</center>of the international wind industry, and added '''18’928 Megawatt''' within one year, accounting for more than 50 % of the world market for new wind turbines.| Doubly fed induction machine* The wind sector in 2010 employed '''670’000 persons''' worldwide.* Nuclear disaster in Japan and oil spill in Gulf of Mexico will have long-term impact on the prospects of wind energy. Governments need to urgently reinforce their wind energy policies.* WWEA sees a global capacity of '''600’000 Megawatt''' as possible by the year 2015 and more than '''1’500’000 Megawatt''' by the year 2020.
|-| style="background-colorSource:#99ccff"| <center>'''3'''</center>| <center>[http://patftwww.usptowwindea.govorg/netacgihome/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=PNimages/7411309&RS=PNstories/7411309 US7411309B2pdfs/worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]</center>| <center>12/08/08</center>| <center>XANTREX TECHNOLOGY INC</center>| Control system for doubly fed induction generator
|-| style="background-color:#99ccff"| <center>'''4'''</center>==Global Market Forecast===| * Global Wind Energy Outlook 2010, provides forecast under <center>[http://patftdolcera.uspto.govcom/netacgiwiki/nph-Parserindex.php?Sect1title=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2FsrchnumForecast_Scenarios three different scenarios] - Reference, Moderate and Advanced.htm&r=1&f=G&l=50&s1=7485980.PN.&OS=PN/7485980&RS=PN/7485980 US7485980B2]</center>| <center>03/02/09</center>* The Global Cumulative Wind Power Capacity is estimated to reach 572,733 MW by the year 2030, under the Reference Scenario| <center>HITACHI LTD</center>* The Global Cumulative Wind Power Capacity is estimated to reach 1,777,550 MW by the year 2030, under the Moderate Scenario| * The Global Cumulative Wind Power converter for doubly-fed power generator systemCapacity is estimated to reach 2,341,984 MW by the year 2030, under the Advanced Scenario* The following chart shows the Global Cumulative Wind Power Capacity Forecast,under the different scenarios:
|-| style="background-color[[Image:#99ccff"Global_Forecast.PNG| <center>'''5'''</center>| <center>1080px|thumb|Global Cumulative Wind Power Capacity Forecast, Source: [http://patftwww.usptogwec.govnet/netacgifileadmin/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=documents/Publications/GWEO%2Fnetahtml202010%2FPTO%2Fsrchnum20final.htm&r=1&f=G&l=50&s1=7800243.PN.&OS=PN/7800243&RS=PN/7800243 US7800243B2pdf Global Wind Energy Outlook 2010]]]</center>| <center>21/09/10</center>| <center>VESTAS WIND SYS AS</center>| Variable speed wind turbine with doubly-fed induction generator compensated for varying rotor speed
|-
| style="background-color:#99ccff"| <center>'''6'''</center>
| <center>[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 US7830127B2]</center>
| <center>09/11/10</center>
| <center>WIND TO POWER SYSTEM S L</center>
| Doubly-controlled asynchronous generator
|}
==Thomson Innovation Search==A search is carried out using a combination of keywords and classifications in Thomson Innovation.The Classifications identified relevant to the scope of the search areSource:[http://www.gwec.net/fileadmin/documents/Publications/GWEO%202010%20final.pdf Global Wind Energy Outlook 2010]
===IPC/ ECLA ClassesMarket Growth Rates===* The growth rate is the relation between the new installed wind power capacity and the installed capacity of the previous year.* With '''23.6 %''', the year 2010 showed the second lowest growth rate of the last decade.
{|border="2" cellspacing="0" cellpadding="4" width="100%"|align = "center" bgcolor = "#99ccff"|'''IPC/ ECLA Class'''|align = "center" bgcolor = "#99ccff"|'''Definition'''|-|align = "center"|[http[Image://wwwWorld_Market_Growth Rates.wipo.int/ipcpub/#refresh=page¬ion=scheme&version=20110101&symbol=F03D0009000000 F03D9/00]PNG|Adaptations of wind motors for special use; Combinations of wind motors with apparatus driven thereby (aspects predominantly concerning driven apparatus)|-|align = "center"| [http://v3.espacenet.com/eclasrch?classification=ecla&locale=en_EP&ECLA=f03d9/00c F03D9/00C]600px|Adaptations of wind motors for special use; Combinations of wind motors with apparatus driven thereby (aspects predominantly concerning driven apparatus)/ the apparatus being an electrical generatorthumb|-|align = "center"|[httpWorld Market Growth Rates, Source://www.wipo.int/ipcpub/#&refresh=page¬ion=scheme&version=20110101&symbol=H02J0003380000 H02J3/38]|Circuit arrangements for ac mains or ac distribution networks/ Arrangements for parallely feeding a single network by two or more generators, converters or transformers|-|align = "center"|[http://www.wipowwindea.intorg/ipcpubhome/#refresh=page¬ion=scheme&version=20110101&symbol=H02K0017420000 H02K17images/42]|DYNAMO-ELECTRIC MACHINESstories/ Asynchronous induction motors; Asynchronous induction generatorspdfs/ Asynchronous induction generators|-|align = "center"| [http://wwwworldwindenergyreport2010_s.wipo.int/ipcpub/#refresh=page¬ion=scheme&version=20110101&symbol=H02P0009000000 H02P9/00pdf World Wind Energy Report, 2010]]]|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|-|}
===US Classes===* Before 2010, the annual growth rate had continued to increase since the year 2004, '''peaking in 2009 at 31.7%''', the highest rate since 2001.* The highest growth rates of the year 2010 by country can be found in '''Romania''', which increased its capacity by 40 times.* The second country with a growth rate of more than 100 % was '''Bulgaria (112%)'''.* In the year 2009, four major wind markets had more than doubled their wind capacity: '''China, Mexico, Turkey, and Morocco'''.* Next to China, strong growth could be found mainly in '''Eastern European and South Eastern European''' countries: Romania, Bulgaria, Turkey, Lithuania, Poland, Hungary, Croatia and Cyprus, and Belgium.* Africa (with the exception of Egypt and Morocco) and Latin America (with the exception of Brazil), are again lagging behind the rest of the world in the commercial use of wind power. * The Top 10 countries by Growth Rate are shown in the figure listed below (only markets bigger than 200 MW have been considered):
{|border="2" cellspacing="0" cellpadding="4" width="100%"|align = "center" bgcolor = "#99ccff"|'''US Class'''|align = "center" bgcolor = "#99ccff"|'''Definition'''|-|align = "center"|[http[Image://wwwTop_Growth_Countries.uspto.gov/web/patents/classification/uspc290/sched290.htm#C290S044000 290/044]|PRIME-MOVER DYNAMO PLANTS/ ELECTRIC CONTROL/ Fluid-current motors / Wind|-PNG|align = "center"|[http://www.uspto.gov/web/patents/classification/uspc290/sched290.htm#C290S055000 290/055]600px|PRIME-MOVER DYNAMO PLANTS/ FLUID-CURRENT MOTORS/ Windthumb|-|align = "center"|[httpTop Countries by Market Growth Rates, Source://www.uspto.gov/web/patents/classification/uspc318/sched318.htm#C318S727000 318/727]|ELECTRICITY: MOTIVE POWER SYSTEMS/ INDUCTION MOTOR SYSTEMS|-|align = "center"|[http://www.usptowwindea.govorg/webhome/patentsimages/classificationstories/uspc322pdfs/sched322worldwindenergyreport2010_s.htm#C322S047000 322/047pdf World Wind Energy Report, 2010]]]|ELECTRICITY: SINGLE GENERATOR SYSTEMS/ GENERATOR CONTROL/ Induction generator|-|}
===Concept Table=Geographical Market Distribution=={|border="2" cellspacing="0" cellpadding="4" width="* China became number one in total installed capacity and the center of the international wind industry, and added '''18'928 Megawatt''' within one year, accounting for more than 50%"of the world market for new wind turbines.|align = "center" bgcolor = "#99ccff"|* Major decrease in new installations can be observed in North America and the '''S.NoUSA lost its number one position'''in total capacity to China.|align = "center" bgcolor = "#99ccff"|* Many Western European countries are showing stagnation, whereas there is strong growth in a number of Eastern European countries.* '''Concept1Germany'''keeps its number one position in Europe with '''27'215 Megawatt''', followed by Spain with 20'676 Megawatt.|align = "center" bgcolor = "#99ccff"|* The highest shares of wind power can be found in three European countries: '''Concept1Denmark (21.0%), Portugal (18.0 %) and Spain (16.0%)'''.|align = "center" bgcolor = "#99ccff"|* '''Concept1Asia'''accounted for the largest share of new installations '''(54.6%)''', followed by '''Europe (27.0%)''' and '''North America (16.7 %)'''.|-|align = "center"|* '''Latin America (1|Doubly fed|Induction|Generator |-|align = "center"|.2|Double output|Asynchronous|Machines|-|align = "center"|3|Dual fed||Systems|-|align = "center"|%)''' and '''Africa (0.4%)''' still played only a marginal role in new installations.|Dual feed|||* Africa: North Africa represents still lion share of installed capacity, wind energy plays hardly a role yet in Sub-Sahara Africa.|align = "center"|5|Dual output|||* Nuclear disaster in Japan and oil spill in Gulf of Mexico will have long-|}term impact on the prospects of wind energy. Governments need to urgently reinforce their wind energy policies.
===Search Strategy===Source: [http://www.wwindea.org/home/images/stories/pdfs/worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]
The databases covered in regional breakdowns for the search includeperiod 2009-2030 has been provided for the following three scenarios:;# [[Regional Breakdown: Reference scenario (GWEO 2010)]];# [[Regional Breakdown: Moderate scenario (GWEO 2010)]];# [[Regional Breakdown: US Grant, GB App, US App, FR App, WO App, DE Util, EP Grant, DE Grant, EP App, DE App, JP Util, JP Grant, JP App, CN Util, CN App, KR Util , KR Grant, KR App, Other, DWPI Advanced scenario (GWEO 2010)]]
Time line''Note: To know more about the '''Forecast Scenarios''' [http:01/01/1836 to 07dolcera.com/03wiki/2011index.php?title=Forecast_Scenarios click here]''
{|border="2" cellspacing="0" cellpadding="4" width="100%"|align = "center" bgcolor = "#99ccff"|'''S.No'''|align = "center" bgcolor = "#99ccff"|'''No. of Hits'''|align = "center" bgcolor = "#99ccff"|'''Remarks'''|align = "center" bgcolor = "#99ccff"|'''Search String'''|Country-|align wise Market Distribution= "center"|1|align = "center"|864 hits|Doubly fed induction generator keywords|CTB=(((((Doubl*3 or dual*3 or two) adj3 (power*2 or output*4 or control*4 or fed or feed*3)) near5 (induction or asynchronous)) near5 (generat*3 or machine*1 or dynamo*1)) OR DFIG);|-|align = "center"|2|align = "center"|108 hits|Induction motor classes AND Doubly fed generator keywords|(UC=(318/727 OR 322/047) OR AIOE=(H02K001742)) AND ALL=(((((Doubl*3 or dual*3 or two) adj3 (power*2 or output*1 or control*4 or fed or feed*3)) near5 (generat*3 or machine*1 or dynamo*1))) OR DFIG);|-|align = "center"|3|align = "center"|757 hits|Broad classes of generators AND Doubly fed induction generator keywords|(UC=(290/044 OR 290/055) OR AIOE=(F03D000900C OR H02J000338 OR F03D0009* OR H02P0009*)) AND ALL=(((((Doubl*2 or dual*3 or two) adj3 (power*2 or output*1 or control*3 or fed or feed*3)) near5 (induction or asynchronous)) near5 (generat*3 or machine*1 or dynamo*1)) or DFIG);|-|align = "center"|4|align = "center"|257 hits|French keywords| CTB=((((Doubl*3 or dual*3or ADJ two or deux) near4 (nourris or feed*3 or puissance or sortie*1 or contrôle*1)) near4 (induction or asynchrone*1) near4 (générateur*1 or generator*1 or machine*1 or dynamo*1)) or DFIG);|-|align = "center"|5|align = "center"|302 hits|German keywords|CTB=(((((doppel*1 or dual or two or zwei) adj3 (Ausgang or Ausgänge or Kontroll* or control*4 or gesteuert or Macht or feed*1 or gefüttert or gespeiste*1)) or (doppeltgefüttert or DOPPELTGESPEISTE*1)) near4 (((Induktion or asynchronen) near4 (generator*2 or Maschine*1 or dynamo*1)) or (INDUKTION?MASCHINEN or INDUKTION?generatoren or Asynchronmaschine or Asynchrongenerator))) or DFIG);|-|align = "center"|6|align = "center"|1358 hits||ALL=(((((((Doubl*3 or dual*3) adj3 (power*2 or output*4 or control*4 or fed or feed*3))) near5 (generat*3 or machine*1 or dynamo*1))) same wind) or (DFIG same wind)) AND DP>=(18360101);|-|align = "center"|7|align = "center"|'''1807 hits (916 INPADOC Families)'''|Combined Query|1 OR 2 OR 3 OR 4 OR 5 OR 6|-|}
==Taxonomy==* In 2010, the Chinese wind market represented more than half of the world market for new wind turbines adding '''18.9 GW''', which equals a market share of '''50.3%'''.<mm>[[mmap825* A sharp decrease in new capacity happened in the USA whose share in new wind turbines fell down to '''14.9% (5.6 GW)''', after 25.9% or 9.9 GW inthe year 2009.* '''Nine further countries''' could be seen as major markets, with turbine sales in a range '''between 0.5 and 1.5 GW''': Germany, Spain, India, UnitedKingdom, France, Italy, Canada, Sweden and the Eastern European newcomer Romania.* Further, '''12 markets''' for new turbines had a medium size '''between 100 and 500 MW''': Turkey, Poland, Portugal, Belgium, Brazil, Denmark, Japan, Bulgaria, Greece, Egypt, Ireland, and Mexico.* By end of 2010, '''20 countries''' had installations of '''more than 1000 MW''', compared with 17 countries by end of 2009 and 11 countries byend of 2005.* Worldwide, '''39 countries''' had wind farms with '''a capacity of 100 Megawatt''' or more installed, compared with 35 countries one year ago, and 24 countries five years ago.* The top five countries (USA, China, Germany, Spain and India)_1represented '''74.mm|Interactive Mindmap|center|title Doubly2%''' of the worldwide wind capacity, significantly more than 72.9 % in the year.* The '''USA and China''' together represented '''43.2%''' of the global wind capacity (up from 38.4 % in 2009).* The newcomer on the list of countries using wind power commercially is a Mediterranean country, '''Cyprus''', which for the first time installed a larger grid-fed Induction Generator]]</mm>connected wind farm, with 82 MW.
==Sample Analysis==A sample of 139 patents from the search are analysed 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="5" width="100%"| rowspan="2" style="background-colorSource:#99ccff"| <center>'''S. No'''</center>| rowspan="2" style="background-color[http:#99ccff"| <center>'''Patent / Publication No/www.'''<wwindea.org/center>| rowspan="2" style="background-color:#99ccff"| <center>'''Publication Year'''<home/center>| rowspan="2" style="background-color:#99ccff"| <center>'''Assignee images/ Applicant'''<stories/center>| rowspan="2" style="background-color:#99ccff"| <center>'''Title'''<pdfs/center>| colspan="2" style="background-color:#99ccff"| <center>'''Doclera Analysis'''</center>worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]
|-The top 10 countries by Total Installed Capacity for the year 2010, is illustrated in the chart below:| style="background-color[[Image:#99ccff"Top_Installed_Countries.PNG| <center>'''Problem'''</center>| style="background-color:#99ccff"600px| <center>'''Solution'''<thumb|Top Countries by Market Growth Rates, Source: [http:/center>/www.wwindea.org/home/images/stories/pdfs/worldwindenergyreport2010_s.pdf World Wind Energy Report, 2010]]]
|-| style="background-colorTo view the Top 10 countries by different other parameters for the year 2010, click on the links below:;#99ccff"| <center>'''1'''</center>[[Top 10 countries by Total New Installed Capacity]]| <center>;# [http:[Top 10 countries by Capacity per Capita (kW//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 US20100117605A1cap)]]</center>| <center>2010<;# [[Top 10 countries by Capacity per Land Area (kW/center>| <center>Woodward SEG GMBH </center>| Method of and apparatus for operating a double-fed asynchronous machine in the event of transient mains voltage changes| 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 equipmentssq.km)]]| 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 an electrical amplitude in the rotor, ;# [[Top 10 countries by which a reference value of the electrical amplitude is setted in the rotor after attaining a transient mains voltage change, such that the rotor flux approaches the stator flux. Capacity per GDP (kW/ million USD)]]
|To view the '''[[Country-| style="background-color:#99ccff"| <center>wise Installed Wind Power Capacity]]'''2(MW) 2002-2010 (Source: World Wind Energy Association), '''</center>| <center>[http://appft1dolcera.uspto.govcom/netacgiwiki/nph-Parserindex.php?Sect1title=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 US20100045040A1Country-wise_Installed_Wind_Power_Capacity click here]</center>| <center>2010</center>| <center>Vestas Wind Systems</center>| 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 comprensation 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 osicllations and increases the efficinecy of the wind turbine.'''
|-| style="background-color:#99ccff"| <center>'''3'''</center>| <center>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2Country Profiles=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&fChina=G&l=50&s1=%2220090267572%22.PGNR.&OS=DN/20090267572&RS=DN/20090267572 US20090267572A1]</center>| <center>2009</centerbr>'''Wind Energy Outlook for China - 2011 & Beyond'''| <center>Woodward SEG GMBH </centerbr>Despite its rapid and seemingly unhampered expansion, theChinese wind power sector continues to face significantchallenges, including issues surrounding grid access and| Current limitation integration, reliability of turbines and a coherent strategy for a doubledeveloping China’s offshore wind resource. These issues willbe prominent during discussions around the twelfth Five-fed asynchronous machineYear| Abnormal currents can damage the widings Plan, which will be passed in the doubly- fed induction gneratorMarch 2011. Cntrolling these currents with According to the subordinate current controllers cannot be an efficient way draft plan, this is expected to extract reflect the maximum amount of active power.Chinese| 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 government’s continuous and reactive power reference values are limited reinforced commitment to a calculated maximum permissible active and reactive wind power reference valuesdevelopment, 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, national wind energy targetsof 90 GW for 2015 and thus a tension with variable amplitude and frequency is imposed in the rotor200 GW for 2020.
|-| style="background-color:#99ccff"| <center>'''4'''</center>| <center>For a detailed country profile of China please visit this [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 US20090008944A1[China Wind Energy Profile Link]]</center>| style="background-color:#ffffff"| <center>2009</center>| <center>UNIVERSIDAD PUBLICA DE NAVARRA</center>| 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 setpoint current which is the result of adding to the previous setpoint current a new term, called demagnetizing current, It is 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.
|-| style="background-color:#99ccff"| ==India===<centerbr>'''5Wind Energy Main market developments in 2010'''</center>| <centerbr>[http://patftToday the Indian market is emerging as one of the majormanufacturing hubs for wind turbines in Asia.usptoCurrently,seventeen manufacturers have an annual production capacityof 7,500 MW.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2FsrchnumAccording to the WISE, the annual wind turbinemanufacturing capacity in India is likely to exceed17,000 MW by 2013.htm&r=1&f=G&l=50&s1=7355295.PN.&OS=PN/7355295&RS=PN/7355295 US7355295B2]</center>| <center>2008</centerbr>The Indian market is expanding with the leading wind| <center>Ingeteam companies like Suzlon, Vestas, Enercon, RRB Energyand GEnow being joined by new entrants like Gamesa, SSiemens, andWinWinD, all vying for a greater market share.ASuzlon, however,is still the market leader with a market share of over 50%.</centerbr>| Variable speed The Indian wind turbine having an exciter machine and a power converter industry has not connected to the gridbeen significantly affected| a) The active switching of by the semiconductors of the grid side converter injects undesirable high frequency harmonics to the gridfinancial and economic crises.b) The use of power electronic converters (4) connected to Even in the grid (9) causes harmonic distortion face of the network voltage.a| Providing global slowdown, the way that Indian annual wind power is only delivered to the grid through the stator of the doubly fed induction generatormarket hasgrown by almost 68%. However, avoiding undesired harmonic distortion. Grid Flux Orientation (GFO) is used it needs to accurately control be pointed outthat the power injected to the grid. An strong growth in 2010 might have been stimulatedby developers taking advantage of the accelerateddepreciation before this control system option 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 gridphased out.
|-| style="background-color:#99ccff"| <center>'''6'''</center>| <center>For a detailed country profile of India please visit this [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 US20080203978A1[India Wind Energy Profile Link]]</center>| <center>2008</center>| <center>Semikron</center>| 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 supersynchronous range which results tower fluctions.| Providing a back-to-back converter whic 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 sysem is allowed for any speed of wind and reduces the tower fluctuations.
|-| style="background-color:#99ccff"| <center>'''7'''</center>| <center>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2Market Share Analysis=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&fGlobal Market Share=G&l=50&s1=* Vestas leads the Global Market in the 2010 with a 12%2220070210651market share according to Make Consulting, while BTM Consulting reports it to have a 14.8%22market share.PGNR.&OS=DN/20070210651&RS=DN/20070210651 US20070210651A1]</center>| <center>2007</center>| <center>Hitachi* According to Make Consulting, Ltdthe global market share of Vestas has decreased from 19% in 2008, to 14.5% in 2009, to 12% in 2010.</center>| Power converter for doubly-fed power generator system| During * According to BTM Consulting, the ground faultsglobal market share of Vestas has changed from 19% in 2008, excess currents is induced to 12% in the secondary windings and flows into power converter connected o secondar side and may danage the power converter2009, to 14. Conventional methos of incresing 8% in 2010.* According to Make Consulting, the capacity global market share of the power cnverter increases system cost GE Energy has decreased from 18% in 2008, degrade the system and takes time to activate the system 12.5% in 2009, to supply power again10% in 2010.| * The generator provided with a excitation power converter connected to secondary windings market share of a doubly-fed generator via impedance eworld no.g. reactor2 Sinovel, and a diode rectifier connected has been constantly increasing, from 5% in parallel 2008 , to the second windings of the doubly-fed generator via another impedance9. A direct current link of the rectifier is connected 3% in parallel 2009, to a DC link 11% in 2010* The top 5 companies have been occupying more than half of the converter. A controller outputs an on-command Global Market Share from 2008 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.2010
|-| style="background-colorSource:#99ccff"| <center>'''8'''</center>| <center>[http://appft1www.usptomake-consulting.govcom Make Consulting], [http:/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnumwww.html&r=1&f=G&l=50&s1=%2220070132248%22btmgcs.PGNR.&OS=DNcom/20070132248&RS=DN/20070132248 US20070132248A1BTM Global Consulting]</center>| <center>2007</center>| <center>General Electric</center>| 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 vltage restoreer (DVR) is cost expensive. | The protection system has controlled impedance devices.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.
|The chart given below illustrates the Global Market Share Comparison of Major Wind Energy Companies for the period 2008-2010, as provided by two different agencies, Make Consulting and BTM Consulting:| style="background-color[[Image:#99ccff"Market_Share_Comparison.JPG| <center>'''9'''</center>|1080px|thumb|Global Market Share Comparison of Major Companies for the period 2008-2010| <center>, Source: [http://appft1www.usptomake-consulting.govcom Make Consulting], [http:/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnumwww.html&r=1&f=G&l=50&s1=%2220060192390%22btmgcs.PGNR.&OS=DNcom/20060192390&RS=DN/20060192390 US20060192390A1BTM Global Consulting]]]</center>| <center>2006</center>| <center>Gamesa Innovation</center>| Control and protection of a doubly-fed induction generator system| A 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.| 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.
===Market Share - Top 10 Markets===
* While Vestas is the Global Leader, it is the leader in only one of Top 10 markets, which is 10<sup>th</sup> placed Sweden
* But, Vestas is ranked 2<sup>nd</sup> in 5 of Top 10 markets
* Sinovel, ranked 2<sup>nd</sup> globally, features only once in the Top 3 Companies list in the Top 10 markets, but scores globally because it leads the largest market China
* The table given below illustrates the Top 3 players in Top 10 Wind Energy Markets of the world:
{|border="2" cellspacing="0" cellpadding="4" width="50%" align="center"
|bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Market'''</font>
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''MW'''</font>
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''No. 1'''</font>
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''No. 2'''</font>
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''No. 3'''</font>
|-
| stylebgcolor ="background-color:#99ccffDBE5F1"| <center>'''10China'''</center>| <center>[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1align =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 US20050189896A1]</"center>| <center>2005</center>| <center>ABB Research LTD</center>| Method for controlling doubly-fed machine| Controlling the double fed machines on the basis of inveter 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. An 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 on the link below to view detailed analysis sheet for Doubly-Fed Induction Generator Patent Literature<br>'''* [[Media:Doublyfed_induction_generator1.xls| Sample analysis on Doubly-Fed Induction Generator-Patent Literature]]'''<br> ===Top Cited Patents=== {|border="2" cellspacingbgcolor ="0#DBE5F1" cellpadding|18928|align ="4center" widthbgcolor ="75%#DBE5F1"|Sinovel| stylealign ="background-color:#99ccff;center"| <center>'''S No'''</center>| stylebgcolor ="background-color:#99ccff;DBE5F1"| <center>'''Patent / Publication N0'''</center>Goldwind| stylealign ="background-color:#99ccff;center"| <center>'''Title'''</center>| stylebgcolor ="background-color:#99ccff;DBE5F1"| <center>'''Citation Count'''</center>Dongfang
|-
| stylebgcolor ="background-color:#99ccff;DBE5F1"| <center>'''1USA'''</center>| [http://patft.uspto.gov/netacgi/nph-Parser?Sect1align =PTO1&Sect2"center" bgcolor =HITOFF&d"#DBE5F1"|5115|align =PALL&p"center" bgcolor =1&u"#DBE5F1"|GE Energy|align =%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l"center" bgcolor =50&s1=5289041.PN.&OS=PN/5289041&RS=PN/5289041 US5289041A]"#DBE5F1"| Speed control system for a variable speed wind turbineVestas| <align = "center>80</center>" bgcolor = "#DBE5F1"|Siemens
|-
| stylebgcolor ="background-color:#99ccff;DBE5F1"| <center>'''2India'''</center>| [http://patft.uspto.gov/netacgi/nph-Parser?Sect1align =PTO1&Sect2"center" bgcolor =HITOFF&d"#DBE5F1"|2139|align =PALL&p"center" bgcolor =1&u"#DBE5F1"|Suzlon|align =%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l"center" bgcolor =50&s1=4982147.PN.&OS=PN/4982147&RS=PN/4982147 US4982147A]"#DBE5F1"| Power factor motor control systemEnercon| <align = "center>62</center>" bgcolor = "#DBE5F1"|Vestas
|-
| stylebgcolor ="background-color:#99ccff;DBE5F1"| <center>'''3Germany'''</center>| [http://patft.uspto.gov/netacgi/nph-Parser?Sect1align =PTO1&Sect2"center" bgcolor =HITOFF&d"#DBE5F1"|1551|align =PALL&p"center" bgcolor =1&u"#DBE5F1"|Enercon|align =%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l"center" bgcolor =50&s1=5028804.PN.&OS=PN/5028804&RS=PN/5028804 US5028804A]"#DBE5F1"| Brushless doubly-fed generator control systemVestas| <align = "center>51</center>" bgcolor = "#DBE5F1"|Suzlon
|-
| stylebgcolor ="background-color:#99ccff;DBE5F1"| <center>'''4UK'''</center>| [http://patft.uspto.gov/netacgi/nph-Parser?Sect1align =PTO1&Sect2"center" bgcolor =HITOFF&d"#DBE5F1"|1522|align =PALL&p"center" bgcolor =1&u"#DBE5F1"|Siemens|align =%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l"center" bgcolor =50&s1=5239251.PN.&OS=PN/5239251&RS=PN/5239251 US5239251A]"#DBE5F1"| Brushless doubly-fed motor control systemVestas| <align = "center>49</center>" bgcolor = "#DBE5F1"|Gamesa
|-
| stylebgcolor ="background-color:#99ccff;DBE5F1"| <center>'''5Spain'''</center>| [http://patft.uspto.gov/netacgi/nph-Parser?Sect1align =PTO1&Sect2"center" bgcolor =HITOFF&d"#DBE5F1"|1516|align =PALL&p"center" bgcolor =1&u"#DBE5F1"|Gamesa|align =%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l"center" bgcolor =50&s1=6856038.PN.&OS=PN/6856038&RS=PN/6856038 US6856038B2]"#DBE5F1"| Variable speed wind turbine having a matrix converterVestas| <align = "center>43</center>" bgcolor = "#DBE5F1"|GE Energy
|-
| stylebgcolor ="background-color:#99ccff;DBE5F1"| <center>'''6France'''</center>| [http://www.wipo.int/pctdb/en/wo.jsp?WOalign =1999029034 WO1999029034A1]"center" bgcolor = "#DBE5F1"|1186| A method and a system for speed control of a rotating electrical machine with flux composed of two quantitiesalign = "center" bgcolor = "#DBE5F1"|Enercon| <align = "center>36</center>" bgcolor = "#DBE5F1"|Suzlon|align = "center" bgcolor = "#DBE5F1"|Vestas
|-
| stylebgcolor ="background-color:#99ccff;DBE5F1"| <center>'''7Italy'''</center>| [http://www.wipo.int/pctdb/en/wo.jsp?WOalign =1999019963 WO1999019963A1]"center" bgcolor = "#DBE5F1"|948| Rotating electric machinealign = "center" bgcolor = "#DBE5F1"|Gamesa| <align = "center>36</center>" bgcolor = "#DBE5F1"|Vestas|align = "center" bgcolor = "#DBE5F1"|Suzlon
|-
| stylebgcolor ="background-color:#99ccff;DBE5F1"| <center>'''8Canada'''</center>| [http://patft.uspto.gov/netacgi/nph-Parser?Sect1align =PTO1&Sect2"center" bgcolor =HITOFF&d"#DBE5F1"|690|align =PALL&p"center" bgcolor =1&u"#DBE5F1"|Siemens|align =%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l"center" bgcolor =50&s1=7015595.PN.&OS=PN/7015595&RS=PN/7015595 US7015595B2]"#DBE5F1"| Variable speed wind turbine having a passive grid side rectifier with scalar power control and dependent pitch controlGE Energy| <align = "center>34</center>" bgcolor = "#DBE5F1"|Enercon
|-
| stylebgcolor ="background-color:#99ccff;DBE5F1"| <center>'''9Sweeden'''</center>| [http://patft.uspto.gov/netacgi/nph-Parser?Sect1align =PTO1&Sect2"center" bgcolor =HITOFF&d"#DBE5F1"|604|align =PALL&p"center" bgcolor =1&u"#DBE5F1"|Vestas|align =%2Fnetahtml%2FPTO%2Fsrchnum.htm&r"center" bgcolor =1&f"#DBE5F1"|Enercon|align =G&l"center" bgcolor =50&s1=4763058.PN.&OS=PN/4763058&RS=PN/4763058 US4763058A]"#DBE5F1"|Siemens| Method and apparatus for determining the flux angle of rotating field machine or for position-oriented operation of the machine| <align = "center>32</center>" bgcolor = "#DBE5F1" colspan = "5"|''Source: BTM Consult - part of Navigant Consulting - March 2011''
|-
| style}<br clear="background-color:#99ccff;all"| <center>'''10'''</center>| [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 US7095131B2]| Variable speed wind turbine generator| <center>25</center>
|}Source: [http://www.btm.dk/reports/world+market+update+2010 BTM Consult]
===Article Analysis=Company Profiles==
{| border="2" cellspacing="0" cellpadding="5" width="100%"| style="background-color:#83caff"| <center>'''[[Vestas Wind Systems A/S No.]]'''</center>| style="background-color:#83caff"| <center>'''Title [[Suzlon Energy]]'''</center>| style="background-color:#83caff"| <center>'''Publication Year'''</center>| style="background-color:#83caff"| <center>'''Journal / Conference'''</center>| style="background-color:#83caff"| <center>'''Dolcera Summary'''</center>|-| style="background-color:#83caff"| <center>'''1'''</center>| style="background-color:#ffffff"| [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 andIts Responses to Grid Disturbances]| <center>2006-Jan-01</center>| Power Engineering Society General Meeting, 2006. IEEE | Presented dynamic model of the DFIG, including mechanical model, generator model, and PWM voltage source coverters. Vector control strategies adapted for both the RSC and GSC to control speed and reactive power independently. controlling desigining methods, such as pole-placement method and the internal model control are used. Matlab/Simulink is used for simulation.
==Major Wind Turbine Suppliers==
{|border="2" cellspacing="0" cellpadding="4" width="50%" align="center"
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Turbine maker'''</font>
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Rotor blades'''</font>
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Gear boxes'''</font>
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Generators'''</font>
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Towers'''</font>
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Controllers'''</font>
|-
| stylebgcolor ="background-color:#83caffDBE5F1"| <center>'''2'''</center>Vestas| stylebgcolor ="background-color:#ffffffDBE5F1"| [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]Vestas, LM| stylebgcolor ="background-color:#ffffffDBE5F1"| <center>2006-May-23</center>Bosch Rexroth, Hansen, Wingery, Moventas| Power Electronicsbgcolor = "#DBE5F1"| Weier, Electrical DrivesElin, Automation and MotionABB, 2006. SPEEDAM 2006. LeroySomer| 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 techinque and the sytem opertaed in both sub and super synchronous modesbgcolor = "#DBE5F1"| Vestas, achieved good results.NEG, DMI|bgcolor = "#DBE5F1"|Cotas (Vestas),<br>NEG (Dancontrol)
|-
| stylebgcolor ="background-color:#83caffDBE5F1"| <center>'''3'''</center>GE energy| stylebgcolor ="background-color:#ffffffDBE5F1"| [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]LM, Tecsis| <center>2006-Aug-14</center>bgcolor = "#DBE5F1"|Wingery, Bosch, Rexroth, Eickhoff, GE| Power Electronics and Motion Control Conferencebgcolor = "#DBE5F1"|Loher, 2006. IPEMC 2006. CES/IEEE 5th International GE| Proposed a new optimal control strategy of maximum wind power extraction stratagies 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 systembgcolor = "#DBE5F1"|DMI, the simulation results shows the good robustness and high generator efficiency is achieved.Omnical, SIAG|bgcolor = "#DBE5F1"|GE
|-
| stylebgcolor ="background-color:#83caffDBE5F1"| <center>'''4'''</center>Gamesa| stylebgcolor ="background-color:#ffffffDBE5F1"| [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]Gamesa, LM| stylebgcolor ="background-color:#ffffffDBE5F1"| <center>2008-Jan-01</center>Echesa (Gamesa), Winergy, Hansen| Journal of ELECTRICAL ENGINEERINGbgcolor = "#DBE5F1"|Indar (Gamesa), Cantarey| 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. bgcolor = "#DBE5F1"|Gamesa|bgcolor = "#DBE5F1"| Ingelectric (Gamesa)
|-
| stylebgcolor ="background-color:#83caffDBE5F1"| <center>'''5'''</center>Enercon| stylebgcolor ="background-color:#ffffffDBE5F1"| [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 Induciton Generator]| <center>2008-Sep-04</center>| Universities Power Engineering Conference, 2008. UPEC 2008. 43rd International | 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, temparature and time delay for deactivation during fault. |} Click on the link below to view detailed analysis sheet for Doubly-Fed Induction Generator-Non Patent Literature<br>* '''[[Media:Doublyfed_induction_generators1.xls| Sample analysis on Doubly-Fed Induction Generator-Non Patent Literature]]''' ===Top cited Articles===Enercon{| borderbgcolor ="2" cellspacing="0" cellpadding="3" width="100%#DBE5F1"|Direct drive| stylebgcolor ="background-color:#83caff;DBE5F1"| <center>'''S No'''</center>Enercon| stylebgcolor ="background-color:#83caff;DBE5F1"| <center>'''Title'''</center>KGW, SAM| stylebgcolor ="background-color:#83caff;DBE5F1"| <center>'''Citations Count'''</center>Enercon
|-
| stylebgcolor ="background-color:#83caff;DBE5F1"| Siemens<center>'''1'''</centerbr>wind| [http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumberbgcolor =502360 Doubly fed induction generator using back-to-back PWM converters and its application to variable-speed wind-energy generation]"#DBE5F1"|Siemens, LM| <center>906</center>bgcolor = "#DBE5F1"|Winergy|bgcolor = "#DBE5F1"|ABB|bgcolor = "#DBE5F1"|Roug, KGW|bgcolor = "#DBE5F1"| Siemens, KK Electronic
|-
| stylebgcolor ="background-color:#83caff;DBE5F1"| <center>'''2'''</center>Suzlon| [http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumberbgcolor =999610 Doubly fed induction generator systems for wind turbines]"#DBE5F1"|Suzlon| bgcolor = "#DBE5F1"|Hansen, Winergy|bgcolor = "#DBE5F1"| Suzlon,<center>508</centerbr>Siemens|bgcolor = "#DBE5F1"|Suzlon|bgcolor = "#DBE5F1"| Suzlon, Mita Teknik
|-
| stylebgcolor ="background-color:#83caff;DBE5F1"| <center>'''3'''</center>Repower| [http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumberbgcolor =1198317 Dynamic modeling of doubly fed induction generator wind turbines]"#DBE5F1"|LM| <center>274<bgcolor = "#DBE5F1"| Winergy, Renk, Eickhoff|bgcolor = "#DBE5F1"|N/center>A|bgcolor = "#DBE5F1"|N/A|bgcolor = "#DBE5F1"| Mita Teknik, ReGuard
|-
| stylebgcolor ="background-color:#83caff;DBE5F1"| <center>'''4'''</center>Nordex| [http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumberbgcolor =1201089 Modeling and control of a wind turbine driven doubly fed induction generator]"#DBE5F1"|Nordex| <center>271</center>bgcolor = "#DBE5F1"| Winergy, Eickhoff, Maag|bgcolor = "#DBE5F1"|Loher|bgcolor = "#DBE5F1"| Nordex, Omnical|bgcolor = "#DBE5F1"| Nordex, Mita Teknik
|-
| stylealign = "center" bgcolor ="background-color:#83caff;DBE5F1" colspan = "6"| <center>''Source: BTM Consult'5'''</center>| [http://ieeexplore.ieee.org/iel5/60/30892/01432858.pdf?arnumber=1432858 Ridethrough of wind turbines with doubly-fed induction generator during a voltage dip]| <center>246</center>
|-
| style}<br clear="background-color:#83caff;all"| <center>'''6'''</center>| [http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=970114 Dynamic modelling of a wind turbine with doubly fed induction generator]| <center>196</center>
==Products of Top Companies==
{|border="2" cellspacing="0" cellpadding="4" width="100%"
|align = "center" bgcolor = "#4F81BD" width=”42”|<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
|-
| style="background-color:#83caff;"| <center>'''7'''</center>| [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]| <center>174</center>}
= IP Search & Analysis =
== Doubly-fed Induction Generator: Search Strategy ==
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.
===Control Patents===
{|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">'''Patent/Publication No.'''</font>
|align = "center" bgcolor = "#4F81BD" width="15%"|<font color="#FFFFFF">'''Publication Date<br>'''(mm/dd/yyyy)</font>
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Assignee/Applicant'''</font>
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Title'''</font>
|- valign="top"
|align = "center" bgcolor = "#DCE6F1"|1
|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>
|align = "center" bgcolor = "#DCE6F1"|08/02/01
|bgcolor = "#DCE6F1"|Sweo Edwin
|bgcolor = "#DCE6F1"|Brush-less doubly-fed induction machines employing dual cage rotors
|- valign="top"
|align = "center"|2
|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>
|align = "center"|10/11/05
|Spellman High Voltage Electron
|Doubly fed induction machine
|- valign="top"
|align = "center" bgcolor = "#DCE6F1"|3
|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>
|align = "center" bgcolor = "#DCE6F1"|08/12/08
|bgcolor = "#DCE6F1"|Xantrex Technology
|bgcolor = "#DCE6F1"|Control system for doubly fed induction generator
|- valign="top"
|align = "center"|4
|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>
|align = "center"|02/03/09
|Hitachi
|Power converter for doubly-fed power generator system
|- valign="top"
|align = "center" bgcolor = "#DCE6F1"|5
|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>
|align = "center" bgcolor = "#DCE6F1"|09/21/10
|bgcolor = "#DCE6F1"|Vestas Wind Systems
|bgcolor = "#DCE6F1"|Variable speed wind turbine with doubly-fed induction generator compensated for varying rotor speed
|- valign="top"
|align = "center"|6
|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>
|align = "center"|11/09/10
|Wind to Power System
|Doubly-controlled asynchronous generator
|-
| style="background-color:#83caff;"| <center>'''8'''</center>| [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]| <center>150</center>}
|-| style="background-color:#83caff;"| <center>'''9'''</center>| [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]| <center>112</center>=Patent Classes===
{|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">'''Class No.'''</font>
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Class Type'''</font>
|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Definition'''</font>
|-valign="top"
|align = "center" bgcolor = "#DCE6F1"|1
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.wipo.int/ipcpub/#refresh=page¬ion=scheme&version=20110101&symbol=F03D0009000000 F03D9/00 ]</u></font>
|bgcolor = "#DCE6F1"|IPC
|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) '''
|-valign="top"
|align = "center"|2
|<font color="#0000FF"><u>[http://v3.espacenet.com/eclasrch?classification=ecla&locale=en_EP&ECLA=f03d9/00c F03D9/00C ]</u></font>
|ECLA
|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 '''
|-valign="top"
|align = "center" bgcolor = "#DCE6F1"|3
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.wipo.int/ipcpub/#&refresh=page¬ion=scheme&version=20110101&symbol=H02J0003380000 H02J3/38 ]</u></font>
|bgcolor = "#DCE6F1"|IPC
|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 '''
|-valign="top"
|align = "center"|4
|<font color="#0000FF"><u>[http://www.wipo.int/ipcpub/#refresh=page¬ion=scheme&version=20110101&symbol=H02K0017420000 H02K17/42 ]
</u></font>
|IPC
|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
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.wipo.int/ipcpub/#refresh=page¬ion=scheme&version=20110101&symbol=H02P0009000000 H02P9/00 ]</u></font>
|bgcolor = "#DCE6F1"|IPC
|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 '''
|-valign="top"
|align = "center"|6
|<font color="#0000FF"><u>[http://www.uspto.gov/web/patents/classification/uspc290/sched290.htm#C290S044000 290/044]</u></font>
|USPC
|Prime-mover dynamo plants / electric control / Fluid-current motors / '''Wind '''
|-valign="top"
|align = "center" bgcolor = "#DCE6F1"|7
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.uspto.gov/web/patents/classification/uspc290/sched290.htm#C290S055000 290/055]</u></font>
|bgcolor = "#DCE6F1"|USPC
|bgcolor = "#DCE6F1"|Prime-mover dynamo plants / Fluid-current motors / '''Wind'''
|-valign="top"
|align = "center"|8
|<font color="#0000FF"><u>[http://www.uspto.gov/web/patents/classification/uspc318/sched318.htm#C318S727000 318/727]</u></font>
|USPC
|Electricity: motive power systems / '''Induction motor systems '''
|-valign="top"
|align = "center" bgcolor = "#DCE6F1"|9
|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://www.uspto.gov/web/patents/classification/uspc322/sched322.htm#C322S047000 322/047]</u></font>
|bgcolor = "#DCE6F1"|USPC
|bgcolor = "#DCE6F1"|Electricity: single generator systems / Generator control / '''Induction generator '''
|-
| style="background-color:#83caff;"| <center>'''10'''</center>
| [http://ieeexplore.ieee.org/xpls/abs_all.jsp?&arnumber=1432853 Doubly fed induction generator model for transient stability analysis]
| <center>106</center>
|}
Click on the link to download worksheet * '''[[Media:Doubly-fed_induction_generator_worksheet.xls| Doubly-fed induction generator Worksheet]]''' ==IP Trend Analysis=Concept Table=Patenting activity has seen high growth rate in the last two years.[[Image:wind ip publication trends1.jpg|center|550px]]Vestas Wind Systems and General Electric are the major players in this technology field.[[Image:wind Major Players.jpg|center|550px]] ==Dashboard==[[Image:Dashboard12.jpg|center|750px|]] '''Dashboard Link'''<br>'''[http://client.dolcera.com/dashboard/dashboard.html?workfile_id=825 Dashboard for doubly fed induction generator]''' *Flash Player is essential to view the Dashboard =Products={|border="2" cellspacing="0" cellpadding="4" width="100%" | stylealign = "center" bgcolor ="background-color:#99ccff;4F81BD" rowspan = "2" width="38"| <centerfont color="#FFFFFF">'''S . No.'''</centerfont>| stylealign = "center" bgcolor ="background-color:#99ccff;4F81BD"| <centerfont color="#FFFFFF">'''CompanyConcept 1'''</centerfont>| stylealign = "center" bgcolor ="background-color:#99ccff;4F81BD"| <centerfont color="#FFFFFF">'''ProductConcept 2'''</centerfont>| stylealign = "center" bgcolor ="background-color:#99ccff;4F81BD"| <centerfont color="#FFFFFF">'''SpecificationsConcept 3'''</centerfont>
|-
| rowspanalign ="3center" stylebgcolor ="background-color:#99ccff;95B3D7"| <center>'''1Doubly Fed'''</center>| rowspanalign ="3"| <center>[http://www.vestas.com/en/wind-power-plants/procurement/turbine-overview/v80-2.0-mw.aspx" bgcolor = "#/vestas-univers Vestas]</center>95B3D7"|'''Induction'''| <align = "center>V80</center>" bgcolor = "#95B3D7"| Rated power 2.0 MW; Operating temperature -30°C to 40°; Frequency: 50 Hz/60 Hz;Number of poles 4-pole '''Generator'''
|-
| <align = "center>V90</center>" bgcolor = "#DCE6F1"| Rated power 1.8/2.0 MW; Operating temperature -30°C to 40°; Frequency: 50 Hz/60 Hz;Number of poles 4-pole (50 Hz)/6-pole (60 Hz)|bgcolor = "#DCE6F1"|doubly fed|bgcolor = "#DCE6F1"|induction|bgcolor = "#DCE6F1"|generator
|-
| <align = "center>V90 Offshore</center>"|2|double output|asynchronous| Rated power 3.0 MW; Operating temperature -30°C to 40°; Frequency: 50 Hz/60 Hz;Number of poles 4-pole machines
|-
| stylealign = "center" bgcolor ="background-color:#99ccff;DCE6F1"| <center>'''2'''</center>3| <center>[http://www.china-windturbine.com/news/doubly_wind_turbines.htm North Heavy Company]</center>bgcolor = "#DCE6F1"|dual fed| <center>2 MW DFIG</center>bgcolor = "#DCE6F1"| | <nowiki>Rated voltage 690V; rated current 1670A; frequency 50Hz; rotor rated voltage 1840V; rotor rated current 670A;, Poles 4 Pole; rated speed 1660rpm; power speed range of 520-1950rmp; Insulation Class H; protection class IP54; center height H bgcolor = 500mm; motor temperature rise =<95K</nowiki>"#DCE6F1"|systems
|-
| stylealign ="background-color:#99ccff;center"| <center>'''3'''</center>4| <center>[http://webcache.googleusercontent.com/search?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 Gamesa]</center>dual feed| <center>G90</center>| Rated Voltage 690 V ac; Frequency 50 Hz; Protection class IP 54; Number of poles 4; Rotational speed 900:1,900 rpm (rated 1,680 rpm) (50Hz); Rated Stator Current 1,500 A @ 690 V; 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.
|-
| rowspanalign ="4center" stylebgcolor ="background-color:#99ccff;DCE6F1"| <center>'''4'''</center>5| rowspanbgcolor ="4#DCE6F1"| <center>[http://www.nordex-online.com/en/products-services/wind-turbines/n100-25-mw Nordex]</center>dual output| <center>N80</center>bgcolor = "#DCE6F1"| | Rated power 2.5 MW; Rated volatge 690V; frequency 50/60Hz; Cooling systems: liquid/air.bgcolor = "#DCE6F1"|
|-
| } ===Thomson Innovation Search==='''Database:''' Thomson Innovation<br>'''Patent coverage:''' US EP WO JP DE GB FR CN KR DWPI<br> '''Time line:''' 01/01/1836 to 07/03/2011{|border="2" cellspacing="0" cellpadding="4" width="100%"|align = "center" bgcolor = "#4F81BD" width="38"|<font color="#FFFFFF">N90'''S. No.'''</font>|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Concept'''</font>| Rated align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Scope'''</font>|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Search String'''</font>|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''No. of Hits'''</font>|-valign="top"|align = "center" bgcolor = "#DCE6F1"|1|bgcolor = "#DCE6F1"|Doubly-fed Induction Generator: Keywords(broad)|bgcolor = "#DCE6F1"|Claims, Title, and Abstract|bgcolor = "#DCE6F1"|(((((doubl<nowiki>*</nowiki>3 OR dual<nowiki>*</nowiki>3 OR two) ADJ3 (power <nowiki>*</nowiki>2OR 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)|align = "right" bgcolor = "#DCE6F1"|873|-valign="top"|align = "center"|2|Doubly-fed Induction Generator: Keywords(broad)|Full Spec.5 MW; Rated volatge 690V; frequency 50|(((((doubl<nowiki>*</60Hz; Cooling systemsnowiki>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)|align = "center"|<nowiki>-</nowiki>|-valign="top"|align = "center" bgcolor = "#DCE6F1"|3|bgcolor = "#DCE6F1"|Induction Machine: liquidClasses|bgcolor = "#DCE6F1"|US, IPC, and ECLA Classes|bgcolor = "#DCE6F1"|((318/air727 OR 322/047) OR (H02K001742))|align = "center" bgcolor = "#DCE6F1"|<nowiki>-</nowiki>|-valign="top"|align = "center"|4|Generators: Classes|US, IPC, and ECLA Classes|((290/044 OR 290/055) OR (F03D000900C OR H02J000338 OR F03D0009<nowiki>*</nowiki> OR H02P0009<nowiki>*</nowiki>))|align = "center"|<nowiki>-</nowiki>|-valign="top"|align = "center" bgcolor = "#DCE6F1"|5|bgcolor = "#DCE6F1"|Combined Query|align = "center" bgcolor = "#DCE6F1"|<nowiki>-</nowiki>|align = "left" bgcolor = "#DCE6F1"|2 AND 3|align = "right" bgcolor = "#DCE6F1"|109|-valign="top"|align = "center"|6|Combined Query|align = "center"|<nowiki>-</nowiki>|align = "left"|2 AND 4|align = "right"|768|-valign="top"|align = "center" bgcolor = "#DCE6F1"|7|bgcolor = "#DCE6F1"|French Keywords|bgcolor = "#DCE6F1"|Claims, Title, and Abstract|bgcolor = "#DCE6F1"|((((doubl<nowiki>*</nowiki>3 OR dual<nowiki>*</nowiki>3 OR 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"|262|-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"|306|-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"|1375|-valign="top"|align = "center"|10| Top Assignees|align = "center"|<nowiki>-</nowiki>|(vestas* OR (gen* ADJ2 electric*) OR ge OR hitachi OR woodward OR repower OR areva OR gamesa OR ingeteam OR nordex OR siemens OR (abb ADJ2 research) OR (american ADJ2 superconductor*) OR (korea ADJ2 electro*) OR (univ* NEAR3 navarra) OR (wind OR technolog*) OR (wind ADJ2 to ADJ2 power))|align = "center"|-|-valign="top"|align = "center" bgcolor = "#DCE6F1"|11|bgcolor = "#DCE6F1"|Combined Query|align = "center" bgcolor = "#DCE6F1"|<nowiki>-</nowiki>|bgcolor = "#DCE6F1"|2 AND 10|align = "right" bgcolor = "#DCE6F1"|690|-valign="top"|align = "center"|12|Top Inventors|align = "center"|<nowiki>-</nowiki>|((Andersen NEAR2 Brian) OR (Engelhardt NEAR2 Stephan) OR (Ichinose NEAR2 Masaya) OR (Jorgensen NEAR2 Allan NEAR2 Holm) OR ((Scholte ADJ2 Wassink) NEAR2 Hartmut) OR (OOHARA NEAR2 Shinya) OR (Rivas NEAR2 Gregorio) OR (Erdman NEAR2 William) OR (Feddersen NEAR2 Lorenz) OR (Fortmann NEAR2 Jens) OR (Garcia NEAR2 Jorge NEAR2 Martinez) OR (Gertmar NEAR2 Lars) OR (KROGH NEAR2 Lars) OR (LETAS NEAR2 Heinz NEAR2 Hermann) OR (Lopez NEAR2 Taberna NEAR2 Jesus) OR (Nielsen NEAR2 John) OR (STOEV NEAR2 Alexander) OR (W?ng NEAR2 Haiqing) OR (Yuan NEAR2 Xiaoming))|align = "center"|-|-valign="top"|align = "center" bgcolor = "#DCE6F1"|13|bgcolor = "#DCE6F1" |Combined Query|align = "center" bgcolor = "#DCE6F1"|<nowiki>-</nowiki>|bgcolor = "#DCE6F1"|((3 OR 4) AND 10)|align = "right" bgcolor = "#DCE6F1"|899|-valign="top"|align = "center"|14|Final Query|align = "center"|<nowiki>-</nowiki>|1 OR 5 OR 6 OR 7 OR 8 OR 9 OR 11 OR 13|'''2466(1060 INPADOC Families)'''
|-
| } ==Taxonomy==*''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'' {|border="2" cellspacing="0" cellpadding="4" width="100%"|<centermm>N100[[Doubly_fed_Induction_Generator.mm|Interactive Mind-map|center|flash|Doubly-fed Induction Generator|600pt]]</centermm>| Rated power 2} ==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 MW; Rated volatge 690V; frequency 50" width="100%"|align = "center" bgcolor = "#4F81BD" rowspan = "2" width="38"|<font color="#FFFFFF">'''S.No.'''</60Hz; Cooling systems: liquidfont>|align = "center" bgcolor = "#4F81BD" rowspan = "2" |<font color="#FFFFFF">'''Patent/airPublication 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">N117 <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 can 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>| Rated 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 2.|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 MW; Rated volatge 690V; |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/60Hz; Cooling systems20080203978&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: liquid/air/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"|A 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.
|-
| style}Click '''[[Media:Doublyfed_induction_generator1.xls| here]]''' to view the detailed analysis sheet for doubly-fed induction generators patent analysis. ===Article Analysis==={|border="background-2" cellspacing="0" cellpadding="4" width="100%"|align = "center" bgcolor = "#4F81BD" width="38"|<font color:="#FFFFFF">'''S.No.'''</font>|align = "center" bgcolor = "#99ccff;4F81BD"| <font color="#FFFFFF">'''Title'''</font>|align = "center" bgcolor = "#4F81BD" width="105"|<font color="#FFFFFF">'''5Publication Date<br>'''(mm/dd/yyyy)</font>|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Journal/Conference'''</font>| align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Dolcera Summary'''</font>|-valign="top"|align = "center" bgcolor = "#DCE6F1"|1|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://wwwieeexplore.converteamieee.comorg/majicsearch/pageServerfreesrchabstract.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 ]</1704040148u></enfont>|align = "center" bgcolor = "#DCE6F1"|01/index01/06|bgcolor = "#DCE6F1"|Power Engineering Society General Meeting, 2006.html ConverteamIEEE |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 ]</centeru></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">DFIG<u>[http:/center/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">NA<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.
|-
| style}Click '''[[Media:Doublyfed_induction_generators1.xls| here]]''' to view the detailed analysis sheet for doubly-fed induction generators article analysis.<br> ===Top Cited Patents==={|border="background-2" cellspacing="0" cellpadding="4" width="100%"|align = "center" bgcolor = "#4F81BD" width="38"|<font color:="#99ccff;FFFFFF">'''S. No.'''</font>|align = "center" bgcolor = "#4F81BD"| <font color="#FFFFFF">'''Patent/Publication No.'''</font>|align = "center" bgcolor = "#4F81BD" width="105"|<font color="#FFFFFF">'''6Publication Date'''<br>(mm/dd/yyyy)</font>|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Assignee/Applicant'''</font>| 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://geohopatft.enuspto.alibabagov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.comhtm&r=1&f=G&l=50&s1=5289041.PN.&OS=PN/product5289041&RS=PN/2523219235289041 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|-0valign="top"|align = "center"|2|<font color="#0000FF"><u>[http:/1_5MW_doubly_fed_asynchronous_generator/patft.html Xian Geoho Energy Technologyuspto.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.5MW DFIGhtm&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>| Rated power1550KW; Rated speed1755 ralign = "center"|06/min; Speed range975~1970 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/min;Stator rated voltage690V±107015595&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=%; Stator rated current1115A; Rotor rated voltage320V; Rotor rated current430A;Winding connectionY 2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4763058.PN.&OS=PN/ Y; Power factor04763058&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.95 (Lead) ~ 0uspto.95Lag; Protection classIP54; Insulation classH; Work modeS1; Installation modeIM B3; Cooling modeAir cooling; Center high500mm; Pole number4; Weight6950kg 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
|-
| rowspan}===Top Cited Articles==={|border="32" stylecellspacing="background-0" cellpadding="4" width="100%"|align = "center" bgcolor = "#4F81BD" width="38"|<font color:="#99ccff;FFFFFF">'''S. No.'''</font>|align = "center" bgcolor = "#4F81BD"| <font color="#FFFFFF">'''Title'''</font>|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''7Publication Date'''</font>|align = "center" bgcolor = "#4F81BD"|<font color="#FFFFFF">'''Journal/Conference'''</font>| rowspanalign ="3center" bgcolor = "#4F81BD"| <font color="#FFFFFF">'''Citations Count'''</font>|-valign="top"|align = "center" bgcolor = "#DCE6F1"|1|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://wwwieeexplore.tecowestinghouseieee.comorg/productsxpls/custom_engineered/DF_WR_ind_generatorabs_all.html Tecowestinghousejsp?&arnumber=502360 Doubly fed induction generator using back-to-back PWM converters and its application to variable-speed wind-energy generation]</centeru></font>| <align = "center>TW450XX (0" bgcolor = "#DCE6F1"|May.51996|bgcolor = "#DCE6F1"|IEEE Proceedings Electric Power Applications|align = "center" bgcolor = "#DCE6F1"|906|-1 KW)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>| Rated align = "center" bgcolor = "#DCE6F1"|May. 2003|bgcolor = "#DCE6F1"|IEEE Transactions on Power 0Systems|align = "center" bgcolor = "#DCE6F1"|274|-valign="top"|align = "center"|4|<font color="#0000FF"><u>[http://ieeexplore.5 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|-1 KW; Rated voltage valign="top"|align = "center" bgcolor = "#DCE6F1"|5|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http: 460/ 575/ 690 V; frequency 50ieeexplore.ieee.org/iel5/ 60 Hz; No/30892/01432858. Of Poles 4pdf?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; Ambient Temp|<font color="#0000FF"><u>[http://ieeexplore.(°C) 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|-40 to 50; Speed Range (% 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 Synchthe wind turbine with a doubly fed induction generator for grid integration studies]</u></font>|align = "center" bgcolor = "#DCE6F1"|Mar. Speed) 68% 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 134%; -back PWM converters supplying an isolated load from a variable speed wind turbine]</u></font>|align = "center"|Sept. 1996|IEEE Proceedings Electric Power Factor (Leading) Applications|align = "center"|150|-0valign="top"|align = "center" bgcolor = "#DCE6F1"|9|bgcolor = "#DCE6F1"|<font color="#0000FF"><u>[http://ieeexplore.90 to +0ieee.90 ; Insulation Class Horg/F; Efficiency xpls/abs_all.jsp?&arnumber=1432853 Doubly fed induction generator model for transient stability analysis]</u></font>|align = 96% "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
|-
| } ===White Space Analysis===* White-space analysis provides the technology growth and gaps in the technology where further R&D can be done to gain competitive edge and to carry out incremental innovation.* Dolcera provides White Space Analysis in different dimensions. Based on Product, Market, Method of Use, Capabilities or Application or Business Area and defines the exact categories within the dimension.* Below table shows a sample representation of white space analysis for controlling DFIG parameters with converters, based on the sample analysis.{|border="2" cellspacing="0" cellpadding="14" width="20%"| style="background-color:#4F81BD;"| <center>TW500XX (1<font color="#FFFFFF">'''White Space of converters used to control'''</font></center>| style="background-2 KW)color:#4F81BD;"| <center><font color="#FFFFFF">'''Active power'''</font></center>| Rated style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Reactive Power 1'''</font></center>| style="background-2 kWcolor:#4F81BD; Rated voltage "| <center><font color="#FFFFFF">'''Decoupled P-Q control'''</font></center>| style="background-color: 460#4F81BD;"| <center><font color="#FFFFFF">'''Field oriented control'''</ 575font></ 690 Vcenter>| style="background-color:#4F81BD; frequency 50"| <center><font color="#FFFFFF">'''Direct torque control'''</ 60 Hzfont></center>| style="background-color:#4F81BD; No. Of Poles 4"| <center><font color="#FFFFFF">'''Speed control'''</6font></center>| style="background-color:#4F81BD; Ambient Temp.(°C) "| <center><font color="#FFFFFF">'''Frequency Control'''</font></center>| style="background-40 to 50color:#4F81BD; Speed Range (% of Synch. Speed) 68% to 134%"| <center><font color="#FFFFFF">'''Pitch control'''</font></center>| style="background-color:#4F81BD; Power Factor (Leading) "| <center><font color="#FFFFFF">'''PWM Technique'''</font></center>| style="background-0.90 to +0.90 color:#4F81BD; Insulation Class H"| <center><font color="#FFFFFF">'''Low voltage ride through'''</Ffont></center>| style="background-color:#4F81BD; Efficiency "| <center><font color= 96% "#FFFFFF">'''Network fault/Grid fault'''</font></center>| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Symmetrical and Asymmetrical Faults'''</font></center>| style="background-color:#4F81BD;"| <center><font color="#FFFFFF">'''Temp control'''</font></center>
|-
| style="background-color:#4F81BD;"| <center>TW560XX (2-3 KW)<font color="#FFFFFF">'''Grid Side active converters'''</font></center>| Rated Power 2[http://appft1.uspto.gov/netacgi/nph-3kW; Rated voltage Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070052394%22.PGNR.&OS=DN/20070052394&RS=DN/20070052394 US20070052394A1][http: 460/ 575/ 690 V; frequency 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=%2220060028025%22.PGNR.&OS=DN/ 60 Hz; No20060028025&RS=DN/20060028025 US20060028025A1]|[http://appft1. Of Poles 4uspto.gov/6; Ambient Tempnetacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.(°C) html&r=1&f=G&l=50&s1=%2220100148508%22.PGNR.&OS=DN/20100148508&RS=DN/20100148508 US20100148508A1][http://appft1.uspto.gov/netacgi/nph-40 to Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100133816%22.PGNR.&OS=DN/20100133816&RS=DN/20100133816 US20100133816A1][http://v3.espacenet.com/searchResults?NUM=EP2166226A1&DB=EPODOC&submitted=true&locale=en_V3&ST=number&compact=false EP2166226A1][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 US20070132248A1][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=%2220070052394%22.PGNR.&OS=DN/20070052394&RS=DN/20070052394 US20070052394A1][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=%2220100096853%22.PGNR.&OS=DN/20100096853&RS=DN/20100096853 US20100096853A1]|[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=%2220100114388%22.PGNR.&OS=DN/20100114388&RS=DN/20100114388 US20100114388A1]||| style="background-color:#ffffff; Speed Range ("| [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=% of Synch2Fnetahtml%2FPTO%2Fsrchnum. Speed) 68html&r=1&f=G&l=50&s1=% to 1342220090008938%22.PGNR.&OS=DN/20090008938&RS=DN/20090008938 US20090008938A1]| style="background-color:#ffffff; Power Factor (Leading) "| [http://www.wipo.int/pctdb/en/wo.jsp?WO=2010079234 WO2010079234A1][http://appft1.uspto.gov/netacgi/nph-0Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.90 to +0html&r=1&f=G&l=50&s1=%2220090230689%22.90 PGNR.&OS=DN/20090230689&RS=DN/20090230689 US20090230689A1][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=%2220090206606%22.PGNR.&OS=DN/20090206606&RS=DN/20090206606 US20090206606A1][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=%2220070024247%22.PGNR.&OS=DN/20070024247&RS=DN/20070024247 US20070024247A1]|[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=%2220090206606%22.PGNR.&OS=DN/20090206606&RS=DN/20090206606 US20090206606A1][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=%2220080129050%22.PGNR.&OS=DN/20080129050&RS=DN/20080129050 US20080129050A1]|[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=%2220100156192%22.PGNR.&OS=DN/20100156192&RS=DN/20100156192 US20100156192A1][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=%2220070182383%22.PGNR.&OS=DN/20070182383&RS=DN/20070182383 US20070182383A1]| style="background-color:#ffffff; Insulation Class H"| [http:/F/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=%2220100002475%22.PGNR.&OS=DN/20100002475&RS=DN/20100002475 US20100002475A1][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=%2220080296898%22.PGNR.&OS=DN/20080296898&RS=DN/20080296898 US20080296898A1][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=%2220070273155%22.PGNR.&OS=DN/20070273155&RS=DN/20070273155 US20070273155A1][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=%2220070278797%22.PGNR.&OS=DN/20070278797&RS=DN/20070278797 US20070278797A1]|[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=%2220070052244%22.PGNR.&OS=DN/20070052244&RS=DN/20070052244 US20070052244A1][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=%2220070024059%22.PGNR.&OS=DN/20070024059&RS=DN/20070024059 US20070024059A1][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=%2220060238929%22.PGNR.&OS=DN/20060238929&RS=DN/20060238929 US20060238929A1]|[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=%2220070177314%22.PGNR.&OS=DN/20070177314&RS=DN/20070177314 US20070177314A1]| style="background-color:#ffffff; Efficiency >"|[http://v3.espacenet.com/searchResults?NUM=EP2166226A1&DB=EPODOC&submitted=true&locale=en_V3&ST=number&compact=false EP2166226A1][http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u= 96% 2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220090121483%22.PGNR.&OS=DN/20090121483&RS=DN/20090121483 US20090121483A1][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=%2220090008938%22.PGNR.&OS=DN/20090008938&RS=DN/20090008938 US20090008938A1]
|-
| rowspan="2" style="background-color:#99ccff4F81BD;"| <center><font color="#FFFFFF">'''8Grid side passive converters'''</font></center>| rowspan="2"|<center>[http://wwwappft1.acciona-nauspto.comgov/About-Usnetacgi/Ournph-ProjectsParser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220030151259%22.PGNR.&OS=DN/U-S-20030151259&RS=DN/West-Branch20030151259 US20030151259A1]|[http://appft1.uspto.gov/netacgi/nph-Wind-Turbine-Generator-Assembly-PlantParser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.aspx Acciona ]<html&r=1&f=G&l=50&s1=%2220030151259%22.PGNR.&OS=DN/center>20030151259&RS=DN/20030151259 US20030151259A1]| <center>AW1500</center>| Rated Power 1500MW; Voltage 690 V ac; Frequency 50 Hz; Protection class IP 54; Number of poles 4; Rotational speed 900||||[http:1,900 rpm (rated 1,680 rpm) (50Hz); Rated Stator Current 1,500 A @ 690 V; Power factor (standard) 0//appft1.98 CAP uspto.gov/netacgi/nph- 0Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.96 IND at partial loads and html&r=1 at nominal power&f=G&l=50&s1=%2220030151259%22. *; Power factor (optional) 0.95 CAP - 0.95 IND throughout the power rangePGNR.&OS=DN/20030151259&RS=DN/20030151259 US20030151259A1]|||||
|-
| style="background-color:#4F81BD;"| <center>AW3000<font color="#FFFFFF">'''Rotor side converter'''</font></center>| Rated Power 3000MW[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=%2220100142237%22.PGNR.&OS=DN/20100142237&RS=DN/20100142237 US20100142237A1][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=%2220070052394%22.PGNR.&OS=DN/20070052394&RS=DN/20070052394 US20070052394A1][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=%2220060028025%22.PGNR.&OS=DN/20060028025&RS=DN/20060028025 US20060028025A1]|[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=%2220100096853%22.PGNR.&OS=DN/20100096853&RS=DN/20100096853 US20100096853A1][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=%2220100148508%22.PGNR.&OS=DN/20100148508&RS=DN/20100148508 US20100148508A1][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=%2220100133816%22.PGNR.&OS=DN/20100133816&RS=DN/20100133816 US20100133816A1][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 US20070132248A1][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=%2220070052394%22.PGNR.&OS=DN/20070052394&RS=DN/20070052394 US20070052394A1]|[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=%2220100114388%22.PGNR.&OS=DN/20100114388&RS=DN/20100114388 US20100114388A1]||| style="background-color:#ffffff; Voltage 690 V ac"| [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=%2220090008938%22.PGNR.&OS=DN/20090008938&RS=DN/20090008938 US20090008938A1]| style="background-color:#ffffff; Frequency "|[http://www.wipo.int/pctdb/en/wo.jsp?WO=2010079234 WO2010079234A1][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 Hz&s1=%2220090230689%22.PGNR.&OS=DN/20090230689&RS=DN/20090230689 US20090230689A1][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=%2220070024247%22.PGNR.&OS=DN/20070024247&RS=DN/20070024247 US20070024247A1]| style="background-color:#ffffff; Protection class IP 54; Number of poles 4; Rotational speed 900"| [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1,900 rpm (rated &u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1,680 rpm) (50Hz)&f=G&l=50&s1=%2220080129050%22.PGNR.&OS=DN/20080129050&RS=DN/20080129050 US20080129050A1]|[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=%2220070182383%22.PGNR.&OS=DN/20070182383&RS=DN/20070182383 US20070182383A1]| style="background-color:#ffffff; Rated Stator Current "|[http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1,500 A @ 690 V&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100002475%22.PGNR.&OS=DN/20100002475&RS=DN/20100002475 US20100002475A1][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=%2220080296898%22.PGNR.&OS=DN/20080296898&RS=DN/20080296898 US20080296898A1][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=%2220070273155%22.PGNR.&OS=DN/20070273155&RS=DN/20070273155 US20070273155A1][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=%2220070278797%22.PGNR.&OS=DN/20070278797&RS=DN/20070278797 US20070278797A1]| style="background-color:#ffffff; Power factor (standard) 0"|[http://appft1.98 CAP uspto.gov/netacgi/nph- 0Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.96 IND at partial loads and html&r=1 at nominal power&f=G&l=50&s1=%2220080157533%22. *PGNR.&OS=DN/20080157533&RS=DN/20080157533 US20080157533A1][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=%2220070052244%22.PGNR.&OS=DN/20070052244&RS=DN/20070052244 US20070052244A1][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=%2220070024059%22.PGNR.&OS=DN/20070024059&RS=DN/20070024059 US20070024059A1][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=%2220060238929%22.PGNR.&OS=DN/20060238929&RS=DN/20060238929 US20060238929A1]| style="background-color:#ffffff; Power factor (optional) 0"|[http://appft1.95 CAP uspto.gov/netacgi/nph- 0Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.95 IND throughout the power rangehtml&r=1&f=G&l=50&s1=%2220090273185%22.PGNR.&OS=DN/20090273185&RS=DN/20090273185 US20090273185A1][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=%2220070177314%22.PGNR.&OS=DN/20070177314&RS=DN/20070177314 US20070177314A1]|[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=%2220090121483%22.PGNR.&OS=DN/20090121483&RS=DN/20090121483 US20090121483A1][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=%2220090008938%22.PGNR.&OS=DN/20090008938&RS=DN/20090008938 US20090008938A1]
|-
| style="background-color:#99ccff4F81BD;"| <center><font color="#FFFFFF">'''9Matrix converters'''</centerfont>| </center>|| style="background-color:#ffffff;"| [http://gepowerappft1.comuspto.gov/businessesnetacgi/ge_wind_energynph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220020079706%22.PGNR.&OS=DN/en20020079706&RS=DN/index.htm General electric20020079706 US20020079706A1]</center>| <center>GE 1|[http://appft1.5uspto.gov/2netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.5MW<html&r=1&f=G&l=50&s1=%2220070216164%22.PGNR.&OS=DN/center>20070216164&RS=DN/20070216164 US20070216164A1]| Rated power [http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.5html&r=1&f=G&l=50&s1=%2220090265040%22.PGNR.&OS=DN/220090265040&RS=DN/20090265040 US20090265040A1]|||[http://appft1.5 MW; Frequency (Hz) 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=%2220070216164%22.PGNR.&OS=DN/60;20070216164&RS=DN/20070216164 US20070216164A1]|||||
|}
=Market Research===Major PlayersDolcera Dashboard ==Vestas Wind Systems, General Electric and Gamesa Innovation & Technology are the top players in terms of installed power capacity in the year 2007[[Image:dashboard_features.png|center|750px|]] '''Dashboard Link'''<br>{| border="2" cellspacing="0" cellpadding="4" | stylewidth="background-color:#99ccff;padding:0.079cm;100%"| <center>'''S[https://www.No'''<dolcera.com/center>| style="background-color:#99ccff;padding:0auth/dashboard/dashboard.079cm;"| <center>'''Company'''</center>| colspanphp?workfile_id="2" style="background825 Doubly Fed Induction Generator -color:#99ccff;padding:0.079cm;"| <center>Dashboard] '''Installed Capacity'''</center>|-| stylewidth="padding:0.079cm;100"| <center>1</center>| style="padding[[Image:0dashboard_thumb.079cm;"png| <center>Vestas (Denmark)</center>| colspan="2" style="padding:0.079cm;"100px| <center>4,500 MW</center>]]
|-
| style="padding:0.079cm;"| <center>2</center>
| style="padding:0.079cm;"| <center>GE Energy (United States)</center>
| colspan="2" style="padding:0.079cm;"| <center>3,300 MW</center>
|-
| style="padding:0.079cm;"| <center>3</center>
| style="padding:0.079cm;"| <center>Gamesa (Spain)</center>
| colspan="2" style="padding:0.079cm;"| <center>3,050 MW</center>
|-
| style="padding:0.079cm;"| <center>4</center>
| style="padding:0.079cm;"| <center>Enercon (Germany)</center>
| colspan="2" style="padding:0.079cm;"| <center>2,700 MW</center>
|-
| style="padding:0.079cm;"| <center>5</center>
| style="padding:0.079cm;"| <center>Suzlon (India)</center>
| colspan="2" style="padding:0.079cm;"| <center>2,000 MW</center>
|-
| style="padding:0.079cm;"| <center>6</center>
| style="padding:0.079cm;"| <center>Siemens (Denmark / Germany)</center>
| colspan="2" style="padding:0.079cm;"| <center>1,400 MW</center>
|-
| style="padding:0.079cm;"| <center>7</center>
| style="padding:0.079cm;"| <center>Acciona (Spain)</center>
| style="padding:0.079cm;"| <center>870 MW</center>
|-
| style="padding:0.079cm;"| <center>8</center>
| style="padding:0.079cm;"| <center>Goldwind (China - PRC)</center>
| style="padding:0.079cm;"| <center>830 MW</center>
|-
| style="padding:0.079cm;"| <center>9</center>
| style="padding:0.079cm;"| <center>Nordex (Germany)</center>
| style="padding:0.079cm;"| <center>670 MW</center>
|-
| style="padding:0.079cm;"| <center>10</center>
| style="padding:0.079cm;"| <center>Sinovel (China - PRC)</center>
| style="padding:0.079cm;"| <center>670 MW</center>
|}
*Flash Player is essential to view the Dolcera dashboard
Source:==Key Findings===== Major Players ===* [http://www.mywindpowersystemvestas.com/2009Vestas Wind Energy Systems] and [http:/04/www.ge.com/ General Electric] are the-10-major-wind-power-companies-players in-the-world/ Wind power companieswind energy generation technology.[[Image:Wind_Major_Players.png|center|thumb|700px|'''Major Players''']]
==Market Overview=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''']]
* 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=== IP Activity ===* US, China and Germany together hold more than 50% of the global wind power capacity* Asia and North America have Patenting activity has seen tremendous a very high growth rate in the installed wind power capacity over the last 6 two 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[[Image:Installed capacity 2009ind_pat_act_3.png|600px|center|thumb|Top 10 Cumulative Installed Capacity 2009]][[Image:New capacity.png700px|600px|center|thumb|Top 10 New Installed Capacity 2009]][[Image:Region Capacities.png|600px|center|thumb|Annual Installed Capacity by Region 2003-2009'''Year wise IP Activity''']]
==Market Forecast= Geographical Activity ===* Global wind power capacity could reach 2USA,300 GW by 2030China, providing up to 22% of the world's electricity needsGermany, from the existing 2.2% Spain, and India are very active in 2010wind energy research. * Global wind capacity will stand at 409GW up from 158GW at the end of 2008[[Image:wind_geographical_act. During 2014, 62.5 GW of new capacity will be added to the global total, compared to 38.3 GW in 2009png|center|thumb|700px|'''Geographical Activity''']] === Research Trend ===* The annual growth rates during this period will average 20.9Around 86% patents are on controlling the doubly-fed induction generation(DFIG) which indicates high research activity going on in terms rating and controlling of total installed capacity, and 10the DFIG systems.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 === Issues in the world, driven primarily by China, which is set to continue the rapid upscaling Technology ===* 86% of its wind capacity and hold its position as the world’s largest annual market. Annual additions patent on DFIG operation 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 marketsfocusing on grid connected mode of operation, including Japan, Taiwan, South Korea and suggesting continuous operation of the Philippines, DFIG system during weak and potentially some others* By 2014storm winds, the annual market will reach 14.5 GWgrid voltage sags, and a total of 60 GW will be installed grid faults are major issues in Europe over this five year periodthe current scenario. [[Image:Market forecastWindenergyanalysis.png|800pxjpg|center|1200px|thumb|ANNUAL MARKET FORECAST BY REGION 2009-2013'''Problem Solution Mapping''']]<br>Source:=== Emerging Player ===* [http://www.gwecwoodward.netcom/index.php?id=167 GWEC's Global Wind Report 2009Woodward]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>=
|}
<br>
=References =
{|border="0" cellspacing="0" cellpadding="4" width="100%"
|-valign="top"
|'''Background References'''
# [http://www.brighthub.com/environment/renewable-energy/articles/71440.aspx Wind Energy History]
# [[Media:windenergy.pdf| Wind Energy]]
# [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]
# [http://www.windpowertv.com/forum/index.php?topic=18.0 Different types of wind turbines]
# [http://www.house-energy.com/Wind/Offshore-Onshore.htm Onshore Vs Offshore Wind Turbines]
# [http://library.thinkquest.org/06aug/01335/wind%20Power.htm Wind Power]
# [http://www.ehow.com/list_5938067_types-wind-farms-there_.html Types of Wind Farms]
# [http://www.offshorewindenergy.org/ca-owee/indexpages/Offshore_technology.php?file=offtech_p2.php Offshore Technology]
# [http://windsine.org/?act=spage&f=wind The Fundamentals of Wind Energy]
# [http://windertower.com/ Winder Tower]
# [http://www.thesolarguide.com/wind-power/wind-towers.aspx Wind Towers]
# [http://guidedtour.windpower.org/en/tour/design/concepts.htm Wind Turbine Blades]
# [http://www.wind-energy-the-facts.org/en/part-i-technology/chapter-3-wind-turbine-technology/evolution-of-commercial-wind-turbine-technology/design-styles.html Wind Turbine Design Styles]
# [http://www.awewind.com/Products/TurbineConstruction/MainAssembly/RotorHub/tabid/81/Default.aspx Rotor Hub Assembly]
# [http://www.gears-gearbox.com/wind-turbines.html Gearbox for Wind Turbines]
# [http://guidedtour.windpower.org/en/tour/wtrb/yaw.htm The Wind Turbine Yaw Mechanism]
# [http://guidedtour.windpower.org/en/tour/wtrb/yaw.htm The Wind Turbine Yaw Mechanism]
# [[Media:windturbinegenerators.pdf| Wind Turbine Generators]]
# [http://www.uni-hildesheim.de/~irwin/inside_wind_turbines.html Inside wind turbines]
|'''Image References'''
# [http://www.windsimulators.co.uk/DFIG.htm DFIG Working Principle]
# [http://www.wwindea.org/home/index.php Country share of total capacity]
# [http://www.atlantissolar.com/wind_story.html Wind turbine principle]
# [http://www.windturbinesnow.com/horizontalaxis-windturbines.htm Horizontal axis wind turbine]
# [http://www.solarpowerwindenergy.org/2009/12/25/types-of-wind-turbines/ Vertical axis wind turbine]
# [http://zone.ni.com/devzone/cda/tut/p/id/8189 Pitch control]
# [http://zone.ni.com/devzone/cda/tut/p/id/8189 Yaw control]
# [http://www.eco-trees.org/europes-biggest-onshore-wind-farm-goes-online/ Onshore Wind turbines]
# [http://www.house-energy.com/Wind/Offshore-Onshore.htm Offshore wind turbines]
# [http://www.solarpowerwindenergy.org/2010/04/02/parts-of-a-wind-turbine/ Wind turbine parts]
# [http://www.windsolarenergy.org/map-of-best-locations-for-wind-power.htm Tower height Vs Power output]
# [http://americanrenewableenergycorp.com/towers Tubular tower]
# [http://www.mywindpowersystem.com/2010/03/wind-power-stats-quiet-critics/ Lattice tower]
# [http://itgiproducts.com/energy/windTowers.asp Guy tower]
# [http://itgiproducts.com/energy/windTowers.asp Tiltup tower]
# [http://itgiproducts.com/energy/windTowers.asp Free stand tower]
# [http://www.wind-energy-the-facts.org/en/part-i-technology/chapter-3-wind-turbine-technology/evolution-of-commercial-wind-turbine-technology/design-styles.html Single blade turbine]
# [http://www.trendir.com/green/?start=15 Two blade turbine]
# [http://www.china-windturbine.com/wind-turbines-blades.htm Three blade turbine]
# [http://windturbinesforthehome.com/ Internal nacelle structure]
# [http://syigroup.en.made-in-china.com/product/dbTQyzJOHYRi/China-Iron-Casting-Wind-Mill-Tower-Rotor-Hub.html Rotor hub]
# [http://jiangyinzkforging.en.made-in-china.com/product/hewxIQjbgTpr/China-Wind-Turbine-Shaft-For-Wind-Power-Generator-ALIM2143-.html Shaft system]
# [http://machinedesign.com/article/green-technology-inside-an-advanced-wind-turbine-0605 Gear box]
# [http://www1.eere.energy.gov/windandhydro/wind_how.html Anemometer & Wind vane]
|-
|}
=Contact Dolcera=