Changes
/* Control patents */
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%"
| style="background-color:#ccccff;border:none;padding:0.079cm;"| <center>'''S No'''</center>
| style="background-color:#ccccff;border:none;padding:0.079cm;"| <center>'''Patent / Publication No.'''</center>
| style="background-color:#ccccff;border:none;padding:0.079cm;"| <center>'''Publication Date'''</center>
| style="background-color:#ccccff;border:none;padding:0.079cm;"| <center>'''Assignee / Applicant'''</center>
| style="background-color:#ccccff;border:none;padding:0.079cm;"| <center>'''Title'''</center>
|-
| style="background-color:#ccccff;border:none;padding:0.079cm;"| <center>'''1'''</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=6278211.PN.&OS=PN/6278211&RS=PN/6278211 US6278211B1]</center>
| <center>02/08/01</center>
| <center>SWEO EDWIN A</center>
| Brushless doubly-fed induction machines employing dual cage rotors
|-
| style="background-color:#ccccff;border:none;padding:0.079cm;"| <center>'''2'''</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=6954004.PN.&OS=PN/6954004&RS=PN/6954004 US6954004B2]</center>
| <center>11/10/05</center>
| <center>SPELLMAN HIGH VOLTAGE ELECTRON</center>
| Doubly fed induction machine
|-
| style="background-color:#ccccff;border:none;padding:0.079cm;"| <center>'''3'''</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=7411309.PN.&OS=PN/7411309&RS=PN/7411309 US7411309B2]</center>
| <center>12/08/08</center>
| <center>XANTREX TECHNOLOGY INC</center>
| Control system for doubly fed induction generator
|-
| style="background-color:#ccccff;border:none;padding:0.079cm;"| <center>'''4'''</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=7485980.PN.&OS=PN/7485980&RS=PN/7485980 US7485980B2]</center>
| <center>03/02/09</center>
| <center>HITACHI LTD</center>
| Power converter for doubly-fed power generator system
|-
| style="background-color:#ccccff;border:none;padding:0.079cm;"| <center>'''5'''</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=7800243.PN.&OS=PN/7800243&RS=PN/7800243 US7800243B2]</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:#ccccff;border:none;padding:0.079cm;"| <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.
