Changes
* Research activity mainly going on rating and controlling of the Doubly-fed induction generation systems. Out of 140 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.* It is a known fact that the brush-less operation technology reduces the wear and tear and increases the efficiency and life of the system. This technology is protected by small players, in which Dual Stator Technology Corp plays major role.<br><br><br>
=Introduction=
