Turbines of the year - Drivetrains

WORLDWIDE: The tried-and-tested solutions versus the radical and innovative designs

Revert to DFIG… A typical Vestas 2MW layout, with main shaft supported in two main bearings
Revert to DFIG… A typical Vestas 2MW layout, with main shaft supported in two main bearings


From 2000 to 2010 Vestas used doubly-fed induction generators (DFIG) in its 2MW high-speed geared (HSG) series, but during 2011 introduced permanent magnet generators (PMGs) in the 1.8/2MW Gridstreamer models. This was in line with a trend whereby HSG-PMG (and PMG in general) was widely regarded as superior to HSG-DFIG, being lighter, more compact, featuring superior partial-load efficiency, while one generator model can serve both 50Hz and 60Hz markets. Vestas switched back to DFIG for all 1.8/2MW models in 2013.

Several main suppliers now consider HSG-DFIGs a more cost-effective solution than HSG-PMG as they only require a partial converter of 20-35% rated generator capacity. DFIG-based electrical system conversion losses have also proved less, showing a superior power curve.

GE switched around a decade ago to HSG-PMG in its 2.X series (later 2.5MW model) but in 2012 it reverted to DFIG for this turbine series, prompted by the substantial progress made with DFIG technology, including grid integration capabilities.

Tacke Windtechnik (now GE Energy) first introduced a DFIG in a 1.5MW variable speed HSG turbine during 1996, which marked the start of this drivetrain design's huge popularity. The end to DFIG's product lifecycle has been predicted several times for proving incapable of meeting increasingly stringent future grid integration demands.

Click here for more on the Turbines of the Year 2013

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