Patent ID: 7471007
Filing Date: 2008-12-30
Classification: H02P

Abstract:
1. A wind turbine, comprising: a rotor with at least one rotor blade, the rotor being rotatably arranged with regard to a substantially horizontal rotor axis; an induction generator having rotor windings are coupled to the rotor and having stator coils for coupling to a voltage grid; a feed-in unit to feed currents into the rotor windings; a control unit to control frequency of the fed-in currents based on the rotor rotation frequency; and a unit operable to electrically decouple the feed-in unit from the rotor windings in case of variations of the grid voltage amplitude, wherein the emergency unit comprises a release arrangement to release the rotor current feed-in after decoupling, when the currents generated in the rotor windings that triggered the decoupling by variation of the grid voltage amplitude have declined to a predetermined value.