The DF generator (DFIG) is an asynchronous wound rotor slip ring machine where the rotor windings are connected to a converter via slip rings and brushes. The generator feeds power both from the stator and from the rotor. The doubly-fed converter (1/3 Pn) is smaller compared to a full converter, however even with this smaller converter the generator speed, power and power factor can be controlled to reach power yield with low LCoE (Levelized Cost of Energy). The doubly-fed concept has ability to feed reactive power to support the grid and satisfy basic grid code requirements.

The proven ABB doubly-fed generators have been designed to fit most turbines used today. The standard modular structure - with both air or water cooling - can be modified for different turbine interface connections. The generator features a rigid rotor design for higher overspeed and voltage peak withstand to fit most converter designs used in the markets. The advanced ABB slip ring series is designed for long service life and easy maintenance. Customer specific generators are available by request from 2 MW up to 6 MW.