GE executive product manager Vincent Schellings explained why, ten years ago, GE chose for permanent magnet generators (PMG’s) for the new 2.X-series.
This decision was based upon the expectation that DFIG’s used in the 1.5MW series would be unable to meet future grid (connection) codes.
Another consideration was that PMGs have a reduced mass, while the design enables one generator model for 50Hz and 60Hz wind markets.
However, Schellings said: "This assumption proved wrong. First, DFIG-technology is more cost-effective compared to PMG due to the fact that it only requires a partial converter with 20-35% rated capacity.
"Second, substantial progress has been made with DFIG-technology during the past decade and has continuously proven capable in meeting the latest grid codes. A third benefit is that DFIG electrical conversion losses proved substantially less compared to PMG.
"For our 2.75MW model this loss saving amounts to about 70kW offering a better power curve and enabling a slight generator power increment to 2.85MW."
Schellings added that the new generator type operates at medium-voltage level and will be applied in 2.5-2.85MW model versions.
He concluded that medium-voltage power transport down the tower to the converter and medium-voltage transformer will reduce electrical losses even further, a key overall benefit with increasing tower height.
After 10 years GE goes back to DFIGs
UK: GE Energy is to return to doubly fed induction generators (DFIG's) 10 years after ditching the technology for permanent magnet generators (PMGs).
.png)
.png)
.jpg)
