Cooling a wind turbine generator

An arrangement for cooling a generator mounted in a nacelle of a wind turbine, said arrangement comprising:

• a cooling air inlet at an outer wall of the nacelle for introducing cooling air into a space region inside the nacelle;
• an inlet fan arranged downstream the cooling air inlet and configured to pressurize the introduced cooling air within the space region;
• a filter system arranged downstream the inlet fan and separating the space region from another space region inside the nacelle, said another space region being in communication with portions of the generator to be cooled;
• and
• a duct system structured to guide a portion of cooling air heated by exchange of heat from the generator portions to the cooling air into the space region.

A wind turbine, in particular direct drive wind turbine, comprising:

• a nacelle;
• a generator mounted within the nacelle;
• and
• an arrangement for cooling the generator using ambient cooling air, said arrangement comprising a cooling air inlet at an outer wall of the nacelle for introducing cooling air into a space region inside the nacelle, an inlet fan arranged downstream the cooling air inlet and configured to pressurize the introduced cooling air within the space region, a filter system arranged downstream the inlet fan and separating the space region from another space region inside the nacelle, said another space region being in communication with portions of the generator, and a duct system structured to guide a portion of cooling air heated by exchange of heat from the generator portions to the cooling air into the space region.

A method of cooling a generator mounted in a nacelle of a wind turbine, said method comprising:

• introducing cooling air via a cooling air inlet at an outer wall of the nacelle into a space region inside the nacelle;
• pressurizing the it cooling air within the space region using an inlet fan downstream the cooling air inlet;
• filtering the introduced cooling air by passing the cooling air through a filter system downstream the inlet fan into another space region inside the nacelle;
• and
• guiding, via a duct system, a portion of cooling air heated by exchange of heat from portions of the generator to the cooling air into the space region.