DRIVETRAIN OF WIND TURBINE WITH LUBRICATION SYSTEM AND WIND TURBINE COMPRISING LUBRICATION SYSTEM

Abstract

The present invention relates to a drivetrain of a wind turbine and a wind turbine with the drivetrain, wherein the drivetrain comprises at least a gearbox, a generator and a lubrication system. The lubrication system comprises at least a pump unit, a main filter system, a heat exchanger and a distribution unit. A secondary filter system is arranged upstream relative to the distribution unit and downstream relative to the heat exchanger. The first filter system has at least one first filter with a first filtration range and the secondary filter system has at least one second filter with a second filtration range. The first filtration range differs from the second filtration range.

Claims

1. A drivetrain (6) for a wind turbine (1), comprising: a low speed interface configured to be connected to a rotor of the wind turbine (1), to provide mechanical torque directly or indirectly to a generator (8) having a generator output; wherein the generator (8) comprises a generator rotor rotatably arranged relative to a generator stator and configured to interact with the generator stator via at least one magnetic field; and a lubrication system (10) arranged relative to at least the low speed interface or the generator (8), wherein the lubrication system (10) is configured to circulate a lubrication medium through at least the low speed interface or the generator (8) via a pipe system (18), the lubrication system (10) comprising at least one pump unit (16), at least one main filter system (17), at least one heat exchanger unit (19) and at least one distribution unit (21), wherein the lubrication system (10) further comprises at least one secondary filter system (20), wherein the secondary filter system (20) is arranged downstream relative to the heat exchanger unit (19).

2. The drivetrain according to claim 1, wherein the main filter system (17) comprises at least one main filter with a first filtration rate and the secondary filter system (20) comprises at least one secondary filter with a second filtration rate, wherein the first filtration rate is equal to the second filtration rate.

3. The drivetrain according to claim 1, wherein the main filter system (17) comprises at least one main filter with a first filtration rate and the secondary filter system (20) comprises at least one secondary filter with a second filtration rate, wherein the first filtration rate differs from the second filtration rate.

4. The drivetrain according to claim 3, wherein one of the main and secondary filters is a finer filter and the other of the main and secondary filters is a coarse filter.

5. The drivetrain according to claim 1, wherein a ratio of a second filtration size of the secondary filter system (20) to a first filtration size of the main filter system (17) is between 2 and 50.

6. The drivetrain according to claim 1, wherein the first filtration size is selected within a range between 2.Math.m and 500.Math.m.

7. The drivetrain according to claim 1, wherein the second filtration size is selected within a range between 10.Math.m and 2500.Math.m.

8. The drivetrain according to claim 1, wherein the drivetrain further comprises a gearbox (7) with at least one gear stage, wherein the gearbox (7) comprises a gearbox input configured to transfer torque to the at least one gear stage and a gearbox output configured to be connected to the generator rotor.

9. The drivetrain according to claim 1, wherein the low speed interface comprises a main bearing arrangement (11), the main bearing arrangement having a main bearing housing (13), a main shaft (12) and at least one main bearing (14, 15) arranged between the main shaft (12) and the main bearing housing (13).

10. The drivetrain according to claim 1, wherein the drivetrain (6) is an integrated drivetrain or a direct drive.

11. A wind turbine (1) comprising a wind turbine tower (2), a nacelle (3) arranged on top of the wind turbine tower (2), and a rotor comprising a hub (4) and at least one wind turbine blade (5), wherein the rotor is arranged relative to the nacelle (3) and mechanically connected to a drivetrain (6) of the wind turbine (1), wherein the drivetrain (6) of the wind turbine (1) comprises: a low speed interface configured to be connected to a rotor of the wind turbine (1), to provide mechanical torque directly or indirectly to a generator (8) having a generator output; wherein the generator (8) comprises a generator rotor rotatably arranged relative to a generator stator and configured to interact with the generator stator via at least one magnetic field; and a lubrication system (10) arranged relative to at least the low speed interface or the generator (8), wherein the lubrication system (10) is configured to circulate a lubrication medium through at least the low speed interface or the generator (8) via a pipe system (18), the lubrication system (10) comprising at least one pump unit (16), at least one main filter system (17), at least one heat exchanger unit (19) and at least one distribution unit (21), wherein the lubrication system (10) further comprises at least one secondary filter system (20), wherein the secondary filter system (20) is arranged downstream relative to the heat exchanger unit (19).

Description

DESCRIPTION OF THE DRAWING

[0055] The present invention is described by example only and with reference to the drawings, wherein:

[0056] FIG. 1 shows an exemplary embodiment of a wind turbine,

[0057] FIG. 2 shows a first embodiment of a drivetrain of the wind turbine,

[0058] FIG. 3 shows a second embodiment of a drivetrain of the wind turbine,

[0059] FIG. 4 shows an exemplary embodiment of a main bearing arrangement, and

[0060] FIG. 5 shows an exemplary embodiment of the lubrication system according to present invention.

[0061] In the following text, the figures will be described one by one, and the different parts and positions seen in the figures will be numbered with the same numbers in the different figures. Not all parts and positions indicated in a specific figure will necessarily be discussed together with that figure.

DETAILED DESCRIPTION OF THE INVENTION

[0062] FIG. 1 shows an exemplary embodiment of a wind turbine 1 comprising a wind turbine tower 2, a nacelle 3 arranged on top of the wind turbine tower 2, and a rotor connected to a drivetrain in the nacelle 3. The rotor comprises a hub 4 and at least one wind turbine blade 5 connected to the hub 4. Here, three wind turbine blades 5 are shown, but the hub 5 may be connected to two, four or more wind turbine blades.

[0063] The wind turbine 1 is here shown as an onshore wind turbine, but the wind turbine 1 may also be an offshore wind turbine 1.

[0064] FIG. 2 shows a first exemplary embodiment of a drivetrain 6 of the wind turbine 1, where the rotor is mechanically connected to an input interface of a gearbox 7 for transferring torque to the gear stages of the gearbox 7. The hub 4 may be connected to the gearbox input via a low speed interface.

[0065] An output interface of the gearbox 7 is mechanically connected to a rotor of a generator 8. The generator 8 further comprises a generator stator arranged relative to the generator rotor, each of which comprises a plurality of pole units configured to interact with each other via at least one magnetic field. Rotation of the generator rotor relative to the generator stator generates an electrical output current in the generator 8.

[0066] The output of the generator 8 is connected to power conversion components 9, which are configured to transform the electrical power output of the generator 8 into a power output suitable for an electrical grid. Particularly, the power output may be supplied to the electrical grid via a synchronised grid connection.

[0067] FIG. 3 shows a second exemplary embodiment of the drivetrain 6 of the wind turbine 1, where the rotor is mechanically connected directly to the generator rotor for transferring torque to the generator 8. The hub 4 may be connected directly to the generator rotor via the low speed interface.

[0068] A lubrication system 10 is further connected to at least the gearbox 7, optionally also to the generator 8 as illustrated by the dotted line in FIG. 2. The lubrication system 10 is configured to circulate a lubrication medium, such as oil, through one or more components in the drivetrain 6.

[0069] FIG. 4 shows an exemplary embodiment of a main bearing arrangement 11 arranged between the rotor hub 4 and the gearbox 7. The main bearing arrangement 11 comprises a main shaft 12 configured to be connected to the rotor hub 4 at one end and to be connected to the gearbox input at the other end. The main shaft 12 is arranged within a main bearing housing 13.

[0070] A front main bearing 14 is arranged at the front end of the main shaft 12. Further, a rear main bearing 15 is arranged at the rear end of the main shaft 12. The main bearing housing 13 acts as a seat for the front and rear main bearings 14, 15.

[0071] FIG. 5 shows an exemplary embodiment of the lubrication system 10 according to the present invention. Here, the lubrication system 10 is connected to the gearbox 7 via a pipe system 18, but can also be connected to the main bearing arrangement 11 and/or the generator 8.

[0072] The lubrication system 10 comprises a pump 16 connected to a lubrication output of the gearbox 7. The pump 16 is arranged downstream relative to a main filter system 17 with one or more main filters, which is configured to filter out debris in the lubrication medium. The main filter system 17 is further arranged upstream relative to a heat exchanger 19. The heat exchanger 19 is configured to cool or heat the lubrication medium to a desired temperature.

[0073] A distribution unit 21 is arranged upstream relative to a lubrication input of the gearbox 7. The distribution unit 21 is configured to distribute the lubrication medium to the respective components in the gearbox 7.

[0074] A secondary filter system 20 with one or more secondary filters is arranged downstream relative to the heat exchanger 19. The secondary filter system 20 is further arranged upstream relative to the distribution unit 21. The secondary filter system 20 is configured to further filter out debris in the lubrication medium.

[0075] Preferably, the ratio between the second filtration size of the secondary filters to the first filtration size of the main filters is selected between 2 to 50.