Patent ID: 9677542
Date: 2017-06-13
CPC Classifications: F03D,F05B,F16C,G01K,H02K,Y02E

Claim:
1. A method for operating a direct drive wind turbine the wind turbine including a generator having a stator and a rotor, with the rotor being rotatably supported relative to the stator by at least one bearing, and a control device adapted to control rotational speed of the rotor and/or at least one rotatably supported wind turbine component coupled to the rotor and/or configured to control electric power output of the generator, the method comprising: determining at least one temperature information, wherein the at least one rotatably supported component is one of an outer ring and an inner ring and wherein the at least one temperature information indicates a temperature difference between the outer ring and the inner ring while the outer ring and the inner ring are rotating with respect to each other; and comparing the at least one temperature information with at least one upper temperature information, wherein the at least one upper temperature information indicates an upper threshold temperature difference between the inner ring and the outer ring of the at least one bearing; limiting rotational speed of the rotor and/or the at least one rotatably supported wind turbine component coupled to the rotor to a non-zero value yet, below a wind turbine specific nominal rotational speed of the rotor and/or below the wind turbine specific nominal rotational speed of the at least one rotatably supported wind turbine component coupled to the rotor and/or limiting electric power output of the generator to a non-zero value yet, below a wind turbine specific nominal electric power output of the generator, when the temperature difference between the inner ring and the outer ring of the bearing increases above the upper threshold temperature difference, wherein, when the wind turbine is operated with limited rotational speed of the rotor and/or the at least one rotatably supported wind turbine component coupled to the rotor and wherein the limited rotational speed is at the non-zero value yet, below the wind turbine specific nominal rotational speed of the rotor and/or below the wind turbine specific nominal rotational speed of the at least one wind turbine component coupled to the rotor, operation of the wind turbine is conducted with an adapted operation of at least one cooling device for cooling at least one component of the generator, wherein the operation of the at least one cooling device for cooling at least one component of the generator is adapted in such a manner that an activation temperature of at least one component of the generator at which cooling of the at least one component of the generator is activated is increased above a wind turbine specific nominal activation temperature which is used during normal operation of the wind turbine.