Electric machine with independent rotor cooling device, generator arrangement and wind turbine
The invention relates to an electric machine ( 2 ) comprising a stator ( 2 ) and a rotor that can rotate relative to the stator ( 2 ), the rotor ( 3 ) having a plurality of permanent magnets ( 5 ), also comprising a rotor cooling device ( 8 ) for cooling the rotor ( 3 ), wherein the rotor cooling device ( 8 ) comprises at least one cooling device ( 23 ) for providing a cooling air flow, said rotor cooling device ( 8 ) comprises a control device ( 22 ) which is designed to control at least one cooling device ( 23 ) for adjusting a coolant power provided by the cooling air flow.
1. An electric machine, comprising:
a stator;
a rotor rotatable to the stator and including a plurality of permanent magnets;
a rotor-cooling apparatus for cooling the rotor, said rotor-cooling apparatus including a first cooling device configured to provide a cooling-air flow, a second cooling device in the form of a re-cooler for cooling the cooling-air flow, an air-guiding element configured to guide the cooling-air flow, cooled by the re-cooler, to the rotor in a radial direction of the electric machine to a central region of the rotor and to guide the cooling-air flow from the rotor to the recooler;
a cooling duct configured to guide the cooling-air flow, guided to the rotor, outwardly along the rotor from the central region in an axial direction of the electric machine; and
a stator cooling apparatus for cooling the stator;
wherein the first cooling device comprises a fan which includes a fan impeller for conveying the cooling-air flow and a fan motor for driving the fan impeller so that a cooling power imparted by the rotor-cooling apparatus is independent of a rotational speed of the electric machine and the cooling power of the rotor-cooling apparatus is independent of the stator cooling apparatus.
2. The electric machine of claim 1 , wherein the stator-cooling apparatus is in a circumferential surrounding relation to the stator for cooling the stator.
3. A generator arrangement, comprising:
an electric machine comprising a stator, a rotor rotatable relative to the stator and including a plurality of permanent magnets, a rotor-cooling apparatus for cooling the rotor, said rotor-cooling apparatus including a first cooling device configured to provide a cooling-air flow, a second cooling device in the form of a re-cooler for cooling the cooling-air flow, an air-guiding element configured to guide the cooling-air flow, cooled by the re-cooler, to the rotor in a radial direction of the electric machine to a central region of the rotor and to guide the cooling-air flow from the rotor to the re-cooler, and a cooling duct configured to guide the cooling-air flow, guided to the rotor, outwardly along the rotor from the central region in an axial direction of the electric machine;
a converter apparatus configured to convert an electrical voltage provided by the electric machine in generator mode; and
a stator cooling apparatus for cooling the stator; wherein the first cooling device comprises a fan which includes a fan impeller for conveying the cooling-air flow and a fan motor for driving the fan impeller so that a cooling power imparted by the rotor-cooling apparatus is independent of a rotational speed of the electric machine and the cooling power of the rotor-cooling apparatus is independent of the stator cooling apparatus.
4. The generator arrangement of claim 3 , wherein the converter apparatus comprises a rectifier, which is electrically connected to the electric machine, and a capacitor for compensating a reactive power.
5. The generator arrangement of claim 3 , wherein the stator-cooling apparatus is in a circumferential surrounding relation to the stator for cooling the stator.
6. A wind turbine, comprising a generator arrangement, said generator arrangement comprising an electric machine and a converter apparatus configured to convert an electrical voltage provided by the electric machine in generator mode, said electric machine including a stator, a rotor rotatable relative to the stator and including a plurality of permanent magnets, a rotor-cooling apparatus for cooling the rotor, said rotor-cooling apparatus including a first cooling device configured to provide a cooling-air flow, a second cooling device in the form of a re-cooler for cooling the cooling-air flow, an air-guiding element configured to guide the cooling-air flow, cooled by the re-cooler, to the rotor in a radial direction of the electric machine to a central region of the rotor and to guide the cooling-air flow from the rotor to the re-cooler, a cooling duct configured to guide the cooling-air flow, guided to the rotor, outwardly along the rotor from the central region in an axial direction of the electric machine, and a stator cooling apparatus for cooling the stator, wherein the first cooling device comprises a fan which includes a fan impeller for conveying the cooling-air flow and a fan motor for driving the fan impeller so that a cooling power imparted by the rotor-cooling apparatus is independent of a rotational speed of the electric machine and the cooling power of the rotor-cooling apparatus is independent of the stator cooling apparatus.
7. The wind turbine of claim 6 , wherein the converter apparatus comprises a rectifier, which is electrically connected to the electric machine, and a capacitor for compensating a reactive power.
8. The wind turbine of claim 6 , wherein the stator-cooling apparatus is in a circumferential surrounding relation to the stator for cooling the stator.
9. The electric machine of claim 2 , wherein the stator-cooling apparatus is a water jacket.
10. The generator arrangement of claim 5 , wherein the stator-cooling apparatus is a water jacket.
11. The wind turbine of claim 8 , wherein the stator-cooling apparatus is a water jacket.