Abstract: The disclosure relates to operating a wind turbine generator during heating operation that includes a rotor and a stator. The stator includes a first three-phase system with three first drivetrains and a second three-phase system with three second drivetrains. The rotor is configured to generate a magnetic field and inject an electric current into the first and second three-phase systems during a rotation with the magnetic field. The first three-phase system includes a first switch for short-circuiting the first drivetrains in a closed state and idling them in an open state. The second three-phase system includes a second switch for short-circuiting the second drivetrains in a closed state and idling them in an open state. The heating operation includes a first phase in which the first switch is switched to the closed state and the second switch is switched to the open state, or vice-versa.

Abstract: A method and a wind turbine are provided. The wind turbine includes a gearless generator that is a synchronous generator and includes a stator and a generator rotor. The wind turbine includes a generator filter with modifiable filter properties that is coupled to the stator and configured to filter a stator current. The wind turbine includes a filter controller configured to control the generator filter.

Abstract: A method and a wind turbine are provided. The wind turbine includes a gearless generator that is a synchronous generator and includes a stator and a generator rotor. The wind turbine includes a generator filter with modifiable filter properties that is coupled to the stator and configured to filter a stator current. The wind turbine includes a filter controller configured to control the generator filter.

Abstract: A wind turbine is provided which comprises a rotor comprising at least two rotor blades, an electric generator, which is coupled directly or indirectly to the rotor and generates an electric power, and at least one power electronics unit, which is provided for converting an input voltage with an input frequency into an output voltage with an output frequency. The at least one power electronics unit has at least one varistor unit. The at least one varistor unit has at least one varistor disc with a voltage-dependent resistance and at least one metal disc that is provided in contact with the at least one varistor disc and is a cooling element for cooling the at least one varistor disc.