Drivetrain of a wind turbine with a lubrication system, and wind turbine equipped with a lubrication system

Abstract

The present invention relates to a drivetrain for a wind turbine and a wind turbine equipped with the drivetrain. 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 located upstream of the distribution unit and downstream of the heat exchanger. The first filter system has at least one first filter having a first filtration range, and the second filter system has at least one second filter having a second filtration range. The first filtration range is different from the second filtration range.

Description

Technical Field

[0001] The present invention relates to a drivetrain for a wind turbine. The drivetrain comprises a low-speed interface configured to be connected to a rotor of a wind turbine, a generator having a generator output, and a lubrication system arranged for the low-speed interface or the generator. The lubrication system is configured to circulate a lubricant medium through at least the low-speed interface or the generator via a pipe system. The lubrication system comprises at least a pump unit, a main filter system, a heat exchanger unit and a distribution unit.

[0002] The present invention further relates to a wind turbine provided with a lubrication system. Background Art

[0003] As is well known, debris contamination in lubricating oil for wind turbine gearboxes can cause severe and progressive damage or failure to gearbox components. Accordingly, lubricating oil from the gearbox is circulated through a filtration system before being returned to the gearbox and distributed. The filtration system is configured to remove debris and other undesirable particles from the lubricating oil.

[0004] WO2010 / 052271A1 discloses a lubrication system for a wind turbine, in which lubricating oil is pumped out of a gearbox, passes through a filter and a heat exchanger, and then enters the gearbox. The heat exchanger is arranged upstream of the filter, and can be bypassed by means of a variable flow valve. However, debris or other particles from the heat exchanger or the bypass valve are directed directly back into the gearbox.

[0005] EP3574212B1 discloses a drivetrain for a wind turbine, in which a lubrication system is located relative to the drivetrain. During operation, lubricating oil is pumped by two main pumps and then pumped through return pipes to two filters and further to a heat exchanger. From the heat exchanger, the lubricating oil is led to a manifold distribution unit and then back into the drivetrain. However, debris or other particles from the heat exchanger are led directly back into the gearbox.

[0006] EP2756189B1 discloses a lubrication system for a wind turbine gearbox in which a pump delivers lubricating oil from the gearbox outlet to a filtering device, and further passes the lubricating oil through an oil cooler before it enters the gearbox inlet. The filtering device comprises fine inlet filters and other filters interconnected in parallel to control the pressure drop. However, this solution requires balancing the smoothness of the gears with the viscosity of the lubricating oil.

[0007] CN217736231U discloses a lubrication system for a wind turbine gearbox, in which a mechanical pump and an electric pump are arranged in parallel to send lubricating oil from the gearbox to a filter system and then to an air cooler. From the air cooler, the lubricating oil is directed back to the gearbox via a distribution valve block. The filter system includes a fine filter and a coarse filter. However, debris or other particles from the air cooler are directed back directly into the gearbox.

[0008] Other lubrication systems for wind turbine gearboxes, such as those disclosed in US2013 / 00288843A1, include an oil tank connected to the gearbox via a lubrication circuit. The lubrication circuit comprises a pump and a filter system located downstream of the pump. Lubricating oil is pumped from the tank through the filter system to each section of the gearbox. A heat exchanger within the lubrication circuit is used to control the viscosity and temperature of the lubricating oil pumped into the gearbox. However, the oil tank needs to be cleaned periodically because debris from the gearbox accumulates in the tank. Furthermore, debris or other particles can accumulate on the pump or heat exchanger over time, thereby reducing their efficiency.

[0009] Therefore, an improved lubrication system is needed for the drivetrain of wind turbines. [Overview of the project]

[0010] One object of the present invention is to solve the problems of the prior art described above, or to provide at least an alternative solution.

[0011] One object of the present invention is to provide a drivetrain and wind turbine that reduce the risk of debris from the heat exchanger entering the gearbox.

[0012] One object of the present invention is to provide a drivetrain and wind turbine that reduce the risk of debris entering the gearbox during maintenance of the filter system.

[0013] One object of the present invention is achieved by the drivetrain of a wind turbine described in claim 1. The drivetrain is - A low-speed interface configured to be connected to the rotor of a wind turbine, and configured to provide mechanical torque to a generator directly or indirectly, - A generator having a generator output section, wherein the generator comprises a generator rotor, the generator rotor being rotatably positioned relative to a generator stator and configured to interact with the generator stator via at least one magnetic field, - A lubrication system positioned at least for a low-speed interface or generator, wherein the lubrication system is configured to circulate a lubricating medium through at least a low-speed interface or generator via a piping system, and the lubrication system comprises at least one pump unit, at least one main filter system, at least one heat exchanger unit, and optionally, at least one distribution unit. Equipped with, - The lubrication system further comprises at least one secondary filter system, the secondary filter system being located downstream of the heat exchanger unit.

[0014] This provides further protection for rotating parts and bearings within the drivetrain from contamination from lubrication system components located upstream of the distribution unit. The present invention provides an additional filter system between the distribution unit and the oil regulation components. Furthermore, contaminants from the drivetrain are filtered by the main filter system downstream of one or more oil regulation components.

[0015] The lubrication system may include various oil control components such as heat exchangers and pumps. The heat exchanger may use a second medium to cool or heat the lubricating medium. The second medium may be separated from the lubricating medium. The second medium may be a liquid such as water or a gas such as air. This allows for separate flow of the lubricating medium and the second medium within the heat exchanger.

[0016] The pump may be driven by a motor connected to an energy source. The motor may be an electric motor, a hydraulic motor, or a pneumatic motor. The motor can be driven by a separate energy source or by the mechanical or electric output of the drivetrain. This reduces the need for a separate drive unit within the wind turbine, resulting in reduced costs and weight.

[0017] The main filter system is located upstream of the heat exchanger. Preferably, the main filter may be located downstream of the low-speed interface or the generator's lubrication output section and upstream of the pump. Alternatively, the main filter system may be located between the pump and the heat exchanger. This allows the lubrication medium to filter out most of the contaminants from the drivetrain as it leaves the drivetrain components. This eliminates or at least reduces the need for maintenance of the secondary filter system.

[0018] Furthermore, the secondary filter system is located downstream of the heat exchanger. Preferably, the secondary filter system may be located downstream of the heat exchanger and upstream of the low-speed interface or the generator's distribution unit or lubrication input. Alternatively, the secondary filter system may be located between components of the distribution unit, or between the distribution unit and the lubrication input. This allows contaminants to be filtered out as the lubrication medium enters the drivetrain components, providing stronger protection for each drivetrain component from contamination by the lubrication system components. This eliminates the need for a separate filter at each lubrication input of each drivetrain component, thus reducing the total number of filters required.

[0019] The distribution unit may be a common manifold connected to all drivetrain components, or it may be individual manifolds, each connected to the lubrication input of a dedicated drivetrain component. The distribution unit may also include one or more valves configured to distribute the lubricating medium to the drivetrain components. This allows for the use of a common lubrication circuit for the drivetrain components, or a dedicated lubrication circuit for each drivetrain component.

[0020] Alternatively, the distribution unit may be omitted, and the lubricating medium may be distributed directly to the drivetrain components via a piping system.

[0021] Optionally, the lubricating medium for each drivetrain component can flow into and out of a common tank or chamber. This allows for the use of a shared lubrication system.

[0022] In one embodiment, the main filter system comprises at least one main filter having a first filtration rate, and the secondary filter system comprises at least one secondary filter having a second filtration rate, wherein the first filtration rate is equal to the second filtration rate.

[0023] One or more main filters are arranged in parallel and / or series within the main filter system, and together they define the combined main filtration rate. Similarly, one or more secondary filters are arranged in parallel and / or series within the secondary filter system, and together they define the combined secondary filtration rate.

[0024] By selecting filters for both the main filter system and the secondary filter system, a dual filtration system can be formed. This reduces the risk of debris and other particles from the heat exchanger entering drivetrain components.

[0025] In this embodiment, the main filter system and the secondary filter system may have the same filter configuration and / or the same filtration rate. For example, the main filter system and the secondary filter system may have the same filtration rate but different filter configurations, or the main filter system and the secondary filter system may have the same filter configuration but different filtration rates. Alternatively, the main filter system and the secondary filter system may have the same filter configuration and the same filtration rate.

[0026] In one embodiment, the main filter system comprises at least one main filter having a first filtration rate, and the secondary filter system comprises at least one secondary filter having a second filtration rate, wherein the first filtration rate is different from the second filtration rate.

[0027] Filters of the main filter system and filters of the secondary filter system can be selected to form an alternating double filtration system. This also reduces the risk of debris and other particles from the heat exchanger entering the drivetrain components.

[0028] In this embodiment, the main filter system and the secondary filter system may have different filter configurations and / or different filtration rates. For example, the main filter system and the secondary filter system may have different filtration rates but the same filter configuration. Alternatively, the main filter system and the secondary filter system may have different filtration rates and different filter configurations.

[0029] The filtration size of each main filter and / or secondary filter can be selected based on the temperature range, viscosity and type of the lubricating medium used, as well as the particle size of contaminants. The lubricating medium may be oil or other types of lubricants, preferably synthetic oil or lubricant.

[0030] In one embodiment, one of the main filter and the secondary filter is a finer filter, and the other of the main filter and the secondary filter is a coarser filter.

[0031] The types of main and secondary filters can be selected to filter and remove both fine and coarse debris. For example, the main filter may be configured to filter and remove coarse debris, and the secondary filter may be configured to filter and remove fine debris. Alternatively, one or both of the main and secondary filter systems may be configured to filter and remove both fine and coarse debris. This expands the overall filtration range of the lubrication system, thus reducing the risk of drivetrain component failure and extending the interval between lubrication fluid changes.

[0032] In one embodiment, the ratio of the second filtration size of the secondary filter system to the first filtration size of the main filter system is 2 to 50.

[0033] Based on the drivetrain configuration and the type of lubricating medium used, an optimal ratio can be selected for filtering and removing undesirable debris and other particles. Each main filter may have a first filtration size with a predetermined efficiency. Furthermore, each secondary filter may have a second filtration size with a predetermined efficiency. The applicant has found that an optimal filtration effect can be achieved when the ratio of the second filtration size to the first filtration range is selected between 2 and 50.

[0034] In one embodiment, the first filtration size is selected within the range of 2 μm to 500 μm.

[0035] Preferably, the first filtration size can be selected to filter out most of the undesirable particles or debris by the main filter. Preferably, the main filter can be selected to have a first filtration size of 2 μm to 500 μm. This allows for filtering out most of the debris and other undesirable particles from the drivetrain components before the lubricating medium enters the heat exchanger.

[0036] In one embodiment, the second filtration size is selected within the range of 10 μm to 2500 μm.

[0037] Preferably, the second filtration size of the secondary filter can be selected to filter out at least debris and other undesirable particles that are not removed by the main filter. The heat exchanger may be long and may have small channels that are prone to the release of debris over time due to vibration, for example. Therefore, the second filtration size of the secondary filter can be further selected to filter out debris released from the heat exchanger. Thus, the secondary filter can be selected to have a second filtration size between 10 μm and 2500 μm.

[0038] In one embodiment, the drivetrain further comprises a gearbox having at least one gear stage. The gearbox includes a gearbox input configured to transmit torque to at least one gear stage and a gearbox output configured to be connected to a generator rotor.

[0039] The drivetrain may further include a gearbox having a gearbox input. The gearbox input is configured to connect to the rotor of the wind turbine, for example, to the hub. The gearbox further includes a gearbox output configured to connect to the generator rotor. The gearbox may be positioned between the rotor and the generator rotor. The gearbox may have a single gear stage or multiple gear stages. This makes it possible to convert the low rotational speed of the rotor to the medium or high rotational speed of the generator.

[0040] Optionally, the gearbox may be directly connected to the rotor via a low-speed interface.

[0041] In one embodiment, the low-speed interface comprises a main bearing device, the main bearing device having a main bearing housing, a main shaft, and at least one main bearing positioned between the main shaft and the main bearing housing.

[0042] The gearbox or generator rotor may be indirectly connected to the rotor via a main bearing device. The main bearing device may include a main shaft configured to be connected to the rotor at one end and to the gearbox input at the other end. At least one main bearing may be positioned relative to the main shaft for support. Preferably, a front main bearing and a rear main bearing may be positioned relative to the main shaft. The rear main bearing may be a shared bearing between the main bearing device and the first stage of the gearbox.

[0043] The main bearing system may further comprise a main bearing housing extending around the main shaft. The main bearing housing may be connected at the rear end to a gearbox housing. The main bearing housing can act as a seat for the main bearings (each main bearing).

[0044] In one embodiment, the drivetrain is either an integrated drivetrain or a direct drive.

[0045] The present invention makes it possible to configure the drivetrain as an integrated drivetrain in which the generator, gearbox, and / or main bearing device are integrated to form a compact drivetrain. The lubrication system may be connected to this integrated drivetrain and configured to supply lubrication to the bearings, gear components, and other rotating parts.

[0046] Furthermore, the present invention allows the drivetrain to be configured as a direct drive, omitting the gearbox and / or main bearing device, and with the generator rotor connected to the rotor. The lubrication system may be connected to this direct drive and configured to supply lubrication to the bearings and other rotating parts.

[0047] One object of the present invention is achieved by the wind turbine described in claim 11. The wind turbine comprises a wind turbine tower, a nacelle located at the top of the wind turbine tower, and a rotor having a hub and at least one wind turbine blade, wherein the rotor is positioned relative to the nacelle and mechanically connected to a drivetrain of the wind turbine, and the drivetrain is configured as described above.

[0048] This provides a wind turbine with an improved drivetrain lubrication system compared to conventional lubrication systems. The invention provides additional protection for drivetrain components against contamination from all lubrication system components located upstream of the distribution unit. This also provides protection during main filter maintenance, which can lead to debris intake as debris may enter when the main filter cartridge is removed.

[0049] Preferably, the secondary filter can be selected to have a larger filtration size than the main filter. This allows the main filter to filter and remove most of the debris and other undesirable particles, while the secondary filter can filter and remove debris that has entered during maintenance of the main filter and heat exchanger. [Brief explanation of the drawing]

[0050] The present invention will be described for illustrative purposes only, with reference to the drawings. [Figure 1] An exemplary embodiment of a wind turbine is shown. [Figure 2] A first embodiment of a wind turbine drivetrain is shown. [Figure 3] A second embodiment of the drivetrain for a wind turbine is shown. [Figure 4] An exemplary embodiment of the main bearing device is shown. [Figure 5] An exemplary embodiment of the lubrication system according to the present invention is shown. [Modes for carrying out the invention]

[0051] The following describes each drawing in turn. Different parts and locations shown in different drawings are indicated by the same reference numerals. Not all parts and locations shown in a particular drawing are necessarily explained in conjunction with that drawing. Figure 1 shows an exemplary embodiment of a wind turbine 1. The wind turbine 1 comprises a wind turbine tower 2, a nacelle 3 located at the top of the wind turbine tower 2, and a rotor connected to a drivetrain within the nacelle 3. The rotor comprises a hub 4 and at least one wind turbine blade 5 connected to the hub 4. Although three wind turbine blades 5 are shown herein, the hub 5 may be connected to two, four, or more wind turbine blades.

[0052] Although wind turbine 1 is shown as an onshore wind turbine, wind turbine 1 may also be an offshore wind turbine 1.

[0053] Figure 2 shows a first exemplary embodiment of the drivetrain 6 of the wind turbine 1. The rotor is mechanically connected to the input interface of the gearbox 7 to transmit torque to the gear stages of the gearbox 7. The hub 4 may be connected to the gearbox input via a low-speed interface.

[0054] The output interface of the gearbox 7 is mechanically connected to the rotor of the generator 8. The generator 8 further comprises a generator stator positioned relative to the generator rotor. Each of the generator stator and generator rotor comprises a plurality of pole units configured to interact with each other via at least one magnetic field. The rotation of the generator rotor relative to the generator stator generates an electrical output current in the generator 8.

[0055] The output section of the generator 8 is connected to a power conversion component 9 configured to convert the power output of the generator 8 into a power output suitable for the power grid. In particular, the power output may be supplied to the power grid via a synchronous power grid connection.

[0056] Figure 3 shows a second exemplary embodiment of the drivetrain 6 of the wind turbine 1. The rotor is mechanically connected directly to the generator rotor to transmit torque to the generator 8. The hub 4 may be directly connected to the generator rotor via a low-speed interface.

[0057] The lubrication system 10 is further connected to at least the gearbox 7 and optionally to the generator 8, as shown by the dotted line in Figure 2. The lubrication system 10 is configured to circulate a lubricating medium, such as oil, through one or more components in the drivetrain 6.

[0058] Figure 4 shows an exemplary embodiment of the main bearing device 11 between the rotor hub 4 and the gearbox 7. The main bearing device 11 comprises a main shaft 12, which is connected to the rotor hub 4 at one end and to the gearbox input at the other end. The main shaft 12 is housed within a main bearing housing 13.

[0059] A front main bearing 14 is positioned at the front end of the main shaft 12. Furthermore, a rear main bearing 15 is positioned at the rear end of the main shaft 12. The main bearing housing 13 functions as a seat for the front main bearing 14 and the rear main bearing 15.

[0060] Figure 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 it may also be connected to the main bearing device 11 and / or the generator 8.

[0061] The lubrication system 10 includes a pump 16 connected to the lubrication output section of the gearbox 7. The pump 16 is located downstream of a main filter system 17 of one or more main filters, which is configured to filter and remove debris from the lubrication medium. The main filter system 17 is located further upstream of a heat exchanger, which is configured to cool or heat the lubrication medium to a desired temperature.

[0062] A distribution unit 21 is positioned upstream of the lubrication input section of the gearbox 7. The distribution unit 21 is configured to distribute the lubricating medium to each component within the gearbox 7.

[0063] Downstream of the heat exchanger 19, a secondary filter system 20 having one or more secondary filters is positioned. The secondary filter system 20 is further positioned upstream of the distribution unit 21. The secondary filter system 20 is configured to further filter and remove debris from the lubricating medium.

[0064] Preferably, the ratio of the second filtration size of the secondary filter to the first filtration size of the main filter is selected between 2 and 50.

Claims

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

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

3. The drivetrain according to claim 1, characterized in that the main filter system (19) comprises at least one main filter having a first filtration speed, and the secondary filter system (20) comprises at least one secondary filter having a second filtration speed, wherein the first filtration speed is different from the second filtration speed.

4. The drivetrain according to claim 3, characterized in that one of the main filter and the secondary filter is a finer-grained filter, and the other of the main filter and the secondary filter is a coarser-grained filter.

5. The drivetrain according to any one of claims 1 to 4, characterized in that the ratio of the second filtration size of the secondary filter system (20) to the first filtration size of the main filter system (17) is 2 to 50.

6. The drivetrain according to any one of claims 1 to 5, characterized in that the first filtration size is selected within the range of 2 μm to 500 μm.

7. The drivetrain according to any one of claims 1 to 6, characterized in that the second filtration size is selected within the range of 10 μm to 2500 μm.

8. The drivetrain according to any one of claims 1 to 7, further comprising a gearbox (7) having at least one gear stage, wherein the gearbox (7) comprises a gearbox input section configured to transmit torque to the at least one gear stage, and a gearbox output section configured to be connected to the generator rotor (8).

9. The drivetrain according to any one of claims 1 to 8, wherein the low-speed interface comprises a main bearing device (11), the main bearing device having a main bearing housing (13), a main shaft (12), and at least one main bearing (14, 15) disposed between the main shaft (12) and the main bearing housing (13).

10. The drivetrain according to any one of claims 1 to 8, characterized in that 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) positioned on top of the wind turbine tower (2), and a rotor having a hub (4) and at least one wind turbine blade (5), wherein the rotor is positioned relative to the nacelle (3) and mechanically connected to a drivetrain (6) of the wind turbine (1), and the drivetrain (6) is configured as described in any one of claims 1 to 10.

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