Torque transmission system for a slip ring unit of a wind turbine and method of assembling a slip ring unit

Abstract

To provide a torque transmission system for a slip ring unit of a wind turbine and a method of assembling the slip ring unit.SOLUTION: The slip ring unit is configured to be mounted along a rotational axis of a wind turbine rotor. The slip ring unit comprises an encoder, a rotating part 201 configured to connect to a rotating component of the wind turbine, and a stationary part 202 configured to connect to a stationary component of the wind turbine. The torque transfer system is configured to connect the rotating part of the slip ring unit to a rotating component of the wind turbine with a degree of freedom in the axial and / or radial direction. Further, the torque transfer system is configured to prevent relative displacement in a tangential direction between the rotating part of the slip ring unit and the rotating component of the wind turbine. The present disclosure also relates to a method of assembly of a slip ring unit in a wind turbine.SELECTED DRAWING: Figure 7A-7C

Description

[Technical Field]

[0001] The present disclosure relates to a torque transmission system for a slip ring unit of a wind turbine. The present disclosure further relates to a method of assembling a slip ring unit in a wind turbine, and more particularly in a direct drive wind turbine. [Background technology]

[0002] Modern wind turbines are commonly used to supply electricity to the power grid. This type of wind turbine generally comprises a tower and a rotor disposed on the tower. The rotor, which typically comprises a hub and a number of blades, rotates under the influence of wind on the blades. This rotation generates torque that is typically transmitted through the rotor shaft to a generator, either directly ("direct drive" or "gearless") or through the use of a gearbox. In this way, the generator generates electricity that can be supplied to the power grid.

[0003] Components such as the gearbox (if present), generator, converter, transformer, power cables, cooling system, and structure (e.g., bedplate and frame) may be partially or completely housed in the nacelle. The nacelle typically sits on a yaw bearing, which allows the nacelle to rotate in order to keep the nacelle and rotor aligned with the wind direction.

[0004] Slip ring units, also called rotary electrical joints, are commonly arranged to enable seamless transfer of data signals and power between the stationary portion of the nacelle and the rotating portion of the wind turbine. In particular, slip rings are commonly used to provide control signals and power from the stationary nacelle to blade pitch actuators located in the rotating hub. Additionally, data transmission may be used from the hub and blades to the nacelle to monitor the condition of the wind turbine blades or other rotating components.

[0005] In some cases, rotational position and / or speed sensors, e.g., encoders, may be integrated into the slip ring unit. Such units may be used to provide position and speed information by generating a series of electrical pulses. In this way, the position of the rotor hub relative to the nacelle and the rotational speed of the wind turbine rotor may be determined. These measurements may be used by a wind turbine controller for various purposes, such as wind turbine overspeed control, wind turbine speed regulation for power capture optimization and / or dynamic load reduction, wind turbine speed control for blade sensor monitoring, and safe positioning of the wind turbine rotor during shutdown.

[0006] In a direct drive wind turbine, rotation is transmitted directly from the rotor hub to the generator rotor. A stationary frame may be provided to support the weight of the generator and hub. In some wind turbine configurations, the hub (and generator rotor) is connected to a rotatable shaft. The rotatable shaft is arranged to rotate around the stationary frame. One or more bearings may be provided between the rotatable shaft and the stationary frame.

[0007] The slip ring units of a direct drive wind turbine are typically located inside a stationary frame. The stationary parts of the slip ring units are commonly mounted to the stationary frame such that the axes of the slip rings are substantially aligned with the rotational axis of the wind turbine. The rotating parts of the slip ring units are connected to the rotating part of the wind turbine, such as the rotor hub or rotatable shaft, if present. A torque transmission system is typically utilized to connect the rotating parts of the slip ring units to the rotating part of the wind turbine and transmit rotational torque.

[0008] As wind turbines grow in size, the tolerances in the manufacturing and assembly processes also increase. Furthermore, the distance between the slip ring unit and its respective connections to the stationary and rotating parts of the wind turbine also increases significantly. This is especially true for the connection between the rotating part of the slip ring unit and a fixed point on the rotating part, e.g., the rotor hub or the rotatable shaft. Thus, the tolerances can result in imperfect circular shapes, which translate into variations in the radial length between the fixed points of the torque transmission system to the rotating components of the wind turbine and the connection to the slip ring unit.

[0009] Furthermore, small axial displacements may also occur during rotation of the wind turbine due to tolerances and loads experienced by the bearing system that rotatably supports the rotating part of the wind turbine on the stationary frame.

[0010] Overall, displacements during wind turbine operation pose a challenge to the efficient performance of slip ring units, especially as they can cause high loads at the connections of the torque transmission system, which can eventually damage the torque transmission system, the slip ring units, and / or the fixing points.

[0011] Furthermore, distorted position and / or speed signals may be received by corresponding rotation sensors, e.g., encoders, integrated into the slip ring units. As a result, additional sensors are typically deployed in conventional wind turbines to perform the required control functions.

[0012] The present disclosure provides systems and methods that overcome at least some of the aforementioned drawbacks. Summary of the Invention

[0013] In one aspect of the disclosure, a torque transmission system for a slip ring unit of a wind turbine is provided. The slip ring unit is configured to be mounted along a rotational axis of a wind turbine rotor. The slip ring unit includes an encoder, a rotating portion configured to connect to a rotating component of the wind turbine, and a stationary portion configured to connect to a stationary component of the wind turbine. The torque transmission system is configured to connect the rotating portion of the slip ring unit to the rotating component of the wind turbine with degrees of freedom in the axial and / or radial directions. The torque transmission system is further configured to prevent relative tangential displacement between the rotating portion of the slip ring unit and the rotating component of the wind turbine.

[0014] According to this aspect of the disclosure, relative axial and / or radial displacements between the rotating portion of the slip ring unit and a rotating component of the wind turbine, such as a rotor hub or a rotatable shaft, are absorbed by the torque transmission system. Such radial and / or axial displacements may occur during operation of the wind turbine due to mechanical tolerances and / or deformations caused by loads acting on the wind turbine.

[0015] The absorption of axial and / or radial displacements provides the structural integrity of the system, as otherwise high-intensity forces could damage various components such as the slip ring units, the fixing points of the transmission system relative to the stationary and rotating components, respectively, and / or the torque transmission system itself.

[0016] The torque transmission system is further configured to prevent relative rotational tangential displacement between the rotating part of the slip ring unit and the rotating component of the wind turbine. The avoidance of tangential displacement results in a pure torque transmission from the rotating component of the wind turbine to the rotating part of the slip ring. In this way, the rotation of the rotating part of the slip ring exactly matches the rotation of the wind turbine rotor. As a result, speed fluctuations and / or differences in rotational angular position are avoided.

[0017] In fact, the inventors have found that designs that provide degrees of freedom in all directions, for example, through spherical bearings, are not suitable for certain applications. In particular, such systems can provide a viable solution for simply transferring data and power signals. However, the presence of a degree of freedom in the tangential direction causes fluctuations or distortions in the position and / or speed signals obtained when sensors, e.g., encoders, are integrated into slip ring units. When used in wind turbine controllers, such distorted signals can have significant detrimental effects, limiting both the efficiency of the wind turbine and its operational safety. Among other things, distortions in position and / or rotational speed can cause false overspeed trips, non-detection of actual overspeed events, insufficient accuracy of the rotor's azimuth position during rotor lock, increased load, or improper tracking of the wind turbine's power curve. As a result, the use of additional sensors is typically required in some prior art wind turbines to ensure reliable and safe operation of the wind turbine.

[0018] By limiting the tangential degrees of freedom, the above-mentioned limitations are overcome and the azimuthal position and rotational speed of the wind turbine rotor can be reliably determined. More precise control is achieved, which allows for improved power capture while dynamically reducing the load. Overall, the efficiency and safety of the wind turbine are improved, and the need for redundant or additional sensing devices is eliminated or at least reduced, among other aspects.

[0019] A degree of freedom in a given direction may be understood herein to mean that any component is capable of relative movement in a given direction with respect to another component. The degree of freedom may be established through the use of specific materials (e.g., materials that are flexible or elastic in a given direction) and / or kinematic couplers (e.g., that allow sliding or gliding in any direction while preventing relative movement in another direction).

[0020] In another aspect of the present disclosure, a wind turbine is provided. The wind turbine includes a wind turbine rotor having a rotational axis. The wind turbine further includes a slip ring unit mounted along the rotational axis. The slip ring unit includes an encoder, a rotating portion connected to a rotating component of the wind turbine, and a stationary portion connected to the stationary component of the wind turbine. The rotating portion of the slip ring unit is coupled to the rotating component of the wind turbine. A coupler prevents tangential movement of the rotating portion of the slip ring unit relative to the rotating component of the wind turbine, while allowing the rotating portion of the slip ring unit to perform limited axial and / or radial movement relative to the rotating component of the wind turbine.

[0021] This aspect of the present disclosure provides a wind turbine that may utilize the foregoing aspects of the present disclosure. In one embodiment, the wind turbine may comprise a direct drive or gearless wind turbine. The above-described distortion effects on position and speed readings may be more prevalent in larger wind turbines with direct drive or gearless configurations. In accordance with the present disclosure, such wind turbines may be designed and operated in a more efficient manner to increase energy yield while also improving the safety of various components of the wind turbine.

[0022] Furthermore, the slip ring unit is arranged in an area close to both the stationary component of the wind turbine, e.g. the stationary frame, and the rotating component of the wind turbine, thereby allowing for a more convenient connection. In particular, the rotating component of the wind turbine may be any component of the wind turbine rotor, such as the rotor hub, or a component operatively connected to the wind turbine rotor, such as the generator rotor, i.e. the rotatable shaft.

[0023] In one embodiment comprising a direct-drive wind turbine, the slip ring unit may be mounted along the rotational axis of the wind turbine rotor, i.e., along the central axis of the wind turbine, and may be located in an area close to the interface between the stationary frame and the rotor hub. The stationary part of the slip ring may be connected to the stationary frame, and the rotating part of the slip ring may be connected to a rotatable shaft (if present), which may be rotatably mounted to the stationary frame by one or more bearings. In this way, the distance of the torque transmission system between the slip ring unit and the rotating components of the wind turbine may be optimized, i.e., minimized.

[0024] In an additional aspect, a method of assembling a slip ring with an encoder in a wind turbine is provided. The method includes providing a slip ring unit and providing a torque transmission system. The method further includes connecting a stationary portion of the slip ring unit to a stationary component of the wind turbine and connecting a rotating portion of the slip ring unit to the rotating component of the wind turbine. Connecting the rotating portion of the slip ring unit to the rotating component of the wind turbine includes connecting through the torque transmission system to prevent relative tangential displacement between the rotating portion of the slip ring unit and the rotating component of the wind turbine while providing degrees of freedom in the axial and / or radial directions. In one embodiment, the method may include assembling in a direct drive wind turbine.

[0025] According to this additional aspect of the present disclosure, a universal assembly of slip ring units is provided, the resulting slip ring arrangement exhibiting the advantages described above.

[0026] Additional objects, advantages and features of the embodiments of the present disclosure will become apparent to those skilled in the art upon examination of the description or may be learned by practice.

[0027] Throughout this disclosure, an axial direction is understood as a direction aligned with the axis of rotation of the wind turbine rotor. Such an axial direction may be, but need not necessarily be, substantially horizontal. Some wind turbines may therefore implement a particular tilt, in which case the axis of rotation of the wind turbine rotor, and therefore also the axial direction, may be slightly inclined relative to the horizontal.

[0028] On the other hand, a radial direction is understood as a direction contained in the plane of rotation. The plane of rotation may be substantially vertical, but not necessarily exactly vertical. In the present disclosure, a radial direction corresponds to a direction towards or away from the centre of rotation. When a slip ring unit is arranged along the axis of rotation of the wind turbine rotor, the centre of rotation substantially corresponds to the centre of the slip ring unit.

[0029] Finally, the tangential direction is understood to be the direction in the plane of rotation and perpendicular to the radial direction at any given point along the path of rotation. The tangential direction is sometimes described as the circumferential direction.

[0030] In other words, given a particular point defining a circular path, the radial direction is understood to be the direction connecting that point to the center of the circle about which that point is rotating, while the tangential direction is contained in the plane of rotation and is perpendicular to the radial direction at the corresponding point.

[0031] Non-limiting examples of the present disclosure are described below with reference to the accompanying drawings. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 1 is a schematic diagram illustrating a perspective view of an embodiment of a wind turbine. [Figure 2] FIG. 1 illustrates an example of a hub and nacelle of a wind turbine. [Figure 3] FIG. 1 shows a schematic cross-sectional view of an embodiment of a direct drive wind turbine with a slip ring unit. [Figure 4A-4B]1A-1C are diagrams showing two examples of mounting of slip ring units and corresponding relative orientations. [Figure 5] FIG. 1 shows a schematic diagram of an example of an arrangement of slip ring units in a direct drive wind turbine. [Figure 6] FIG. 10 is a schematic diagram illustrating rotational speed measurements obtained with an encoder disposed within a slip ring unit, where the slip ring unit is not mounted in accordance with the present disclosure. [Figure 7A-7C] FIG. 1 is a schematic diagram of an embodiment of a torque transfer system according to an embodiment of the present disclosure. [Figure 8] FIG. 2 is a schematic diagram of an embodiment of a torque transfer system according to another embodiment of the present disclosure. [Figure 9] 10 is a diagram illustrating a schematic diagram of an embodiment of a torque transfer system according to a further embodiment of the present disclosure. [Figures 10A-10B] FIG. 10 is a schematic diagram illustrating an embodiment of a torque transfer system according to yet another embodiment of the present disclosure. [Figure 11] FIG. 1 shows a flow chart of an embodiment of a method for assembling a slip ring unit in a wind turbine. DETAILED DESCRIPTION OF THE INVENTION

[0033] Reference will now be made in detail to the embodiments of the present disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation, not limitation. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the teachings. For example, features illustrated or described as part of any embodiment may be used in another embodiment to yield yet a further embodiment. Accordingly, the present disclosure is intended to cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0034] FIG. 1 is a perspective view of one example of a wind turbine 10. In this example, wind turbine 10 is a horizontal axis wind turbine. Alternatively, wind turbine 10 may be a vertical axis wind turbine. In this example, wind turbine 10 includes a tower 15 extending from a support system 14 above ground 12, a nacelle 16 mounted on tower 15, and a rotor 18 coupled to nacelle 16. Rotor 18 includes a rotatable hub 20 and at least one rotor blade 22 coupled to and extending outward from hub 20. In this example, rotor 18 has three rotor blades 22. In alternative embodiments, rotor 18 includes more or fewer than three rotor blades 22. Tower 15 may be fabricated from tubular steel to define a cavity (not shown in FIG. 1 ) between support system 14 and nacelle 16. In alternative embodiments, tower 15 is any suitable type of tower having any suitable height. According to alternatives, the tower may be a hybrid tower comprising a concrete section and a tubular steel section, or the tower may be a partial or full lattice tower.

[0035] The rotor blades 22 are spaced about the hub 20 to facilitate rotation of the rotor 18 so that kinetic energy can be transferred from the wind to usable mechanical energy and subsequently to electrical energy. The rotor blades 22 are mated to the hub 20 by coupling their blade root portions 24 to the hub 20 at a plurality of load transfer areas 26. The load transfer areas 26 may include hub load transfer areas and blade load transfer areas (both not shown in FIG. 1 ). Loads induced in the rotor blades 22 are transferred to the hub 20 via the load transfer areas 26.

[0036] In embodiments, rotor blades 22 may have lengths ranging from about 15 meters (m) to about 90 m or more. Rotor blades 22 may have any suitable length that enables wind turbine 10 to function as described herein. For example, non-limiting examples of blade lengths include lengths of 20 m or less, or lengths of 37 m, 48.7 m, 50.2 m, 52.2 m, or greater than 91 m. When wind strikes rotor blades 22 from wind direction 28, rotor 18 rotates about rotor axis 30. As rotor blades 22 rotate and experience centrifugal forces, rotor blades 22 also experience various forces and moments. Thus, rotor blades 22 may deflect and / or rotate from a neutral or unbiased position to a biased position.

[0037] Furthermore, the pitch angle of the rotor blades 22, i.e., the angle that determines the orientation of the rotor blades 22 relative to the wind direction, may be varied by the pitch system 32 to adjust the angular position of at least one rotor blade 22 relative to the wind vector, thereby controlling the load and the power generated by the wind turbine 10. A pitch axis 34 of the rotor blade 22 is also shown. During operation of the wind turbine 10, the pitch system 32 may particularly vary the pitch angle of the rotor blades 22 such that the angle of attack of (some of) the rotor blades is reduced, thereby facilitating a reduction in rotational speed and / or facilitating stalling of the rotor 18.

[0038] In this embodiment, the blade pitch of each rotor blade 22 is individually controlled by the wind turbine controller 36 or pitch control system 80. Alternatively, the blade pitch for all rotor blades 22 may be controlled simultaneously by the control systems.

[0039] Additionally, in this embodiment, as wind direction 28 changes, nacelle 16 may be yaw rotated about yaw axis 38 to position rotor blades 22 relative to wind direction 28 .

[0040] Although in this example, wind turbine controller 36 is shown as being centralized within nacelle 16, wind turbine controller 36 may be a distributed system throughout wind turbine 10, on support system 14, within a wind farm, and / or at a remote control center. Wind turbine controller 36 includes a processor 40 configured to perform the methods and / or steps described herein. Additionally, many of the other components described herein include a processor.

[0041] As used herein, the term "processor" is not limited to integrated circuits referred to in the art as computers, but refers broadly to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application specific integrated circuits, and other programmable circuits, and these terms are used interchangeably herein. It should be understood that the processor and / or control system may further include memory, input channels, and / or output channels.

[0042] 2 is an enlarged cross-sectional view of a portion of wind turbine 10. In this embodiment, wind turbine 10 includes a nacelle 16 and a rotor 18 rotatably coupled to nacelle 16. More specifically, a hub 20 of rotor 18 is rotatably coupled to a generator 42 disposed within nacelle 16 by a main shaft 44, a gearbox 46, a high-speed shaft 48, and a coupler 50. In this embodiment, main shaft 44 is disposed at least partially coaxially with a longitudinal axis (not shown) of nacelle 16. Rotation of main shaft 44 drives gearbox 46, which then drives high-speed shaft 48 by converting the relatively slow rotational motion of rotor 18 and main shaft 44 into relatively faster rotational motion of high-speed shaft 48. The latter is connected to generator 42 for generating electrical energy with the aid of coupler 50. Additionally, a transformer 90 and / or appropriate electronics, switches, and / or inverters may be disposed in the nacelle 16 to convert the electrical energy generated by the generator 42 having a voltage of 400V to 1000V into electrical energy having a medium voltage (10 to 35 kV). The electrical energy is transmitted from the nacelle 16 to the tower 15 via a power cable.

[0043] The gearbox 46, generator 42, and transformer 90 are supported by a main support structure frame of the nacelle 16, which may optionally be embodied as a main frame 52. The gearbox 46 may include a gearbox housing connected to the main frame 52 by one or more torque arms 103. In this embodiment, the nacelle 16 also includes a main forward support bearing 60 and a main aft support bearing 62. Furthermore, the generator 42 may be attached to the main frame 52 by an isolation support means 54, particularly to prevent vibrations of the generator 42 from being introduced into the main frame 52 and thereby creating a source of noise emissions.

[0044] Optionally, the main frame 52 is configured to carry the entire loads caused by the weight of the rotor 18 and nacelle 16 components, as well as wind and rotational loads, and to introduce these loads into the tower 15 of the wind turbine 10. The rotor shaft 44, the generator 42, the gearbox 46, the high-speed shaft 48, the coupler 50, and any associated fastening, supporting, and / or securing devices, including, but not limited to, the supports 52, the forward support bearing 60, and the aft support bearing 62, may be referred to as a drive train 64.

[0045] In some embodiments, the wind turbine may be a direct drive wind turbine without a gearbox 46. The generators 42 operate at the same rotational speed as the rotor 18 in direct drive wind turbines. Therefore, they generally have a much larger diameter than the generators used in wind turbines with gearboxes 46 to provide a similar amount of power as wind turbines with gearboxes.

[0046] The nacelle 16 may also include a yaw drive mechanism 56 that may be used to rotate the nacelle 16 , and thus the rotor 18 , about the yaw axis 38 to control the balance of the rotor blades 22 relative to the wind direction 28 .

[0047] To properly position the nacelle 16 relative to the wind direction 28, the nacelle 16 may also include at least one meteorological measurement system 58, which may include a wind vane and an anemometer. The meteorological measurement system 58 may provide information, which may include the wind direction 28 and / or wind speed, to the wind turbine controller 36. In this example, the pitch system 32 is at least partially disposed within the hub 20 as a pitch assembly 66. The pitch assembly 66 includes one or more pitch drive systems 68 and at least one sensor 70. Each pitch drive system 68 is coupled to a respective rotor blade 22 (shown in FIG. 1 ) to modulate the pitch angle of the rotor blade 22 along the pitch axis 34. Only one of the three pitch drive systems 68 is shown in FIG. 2 .

[0048] In this example, pitch assembly 66 includes at least one pitch bearing 72 coupled to hub 20 and each rotor blade 22 (shown in FIG. 1 ) to rotate each rotor blade 22 about pitch axis 34. Pitch drive system 68 includes a pitch drive motor 74, a pitch drive gearbox 76, and a pitch drive pinion 78. Pitch drive motor 74 is coupled to pitch drive gearbox 76 such that pitch drive motor 74 imparts mechanical force to pitch drive gearbox 76. Pitch drive gearbox 76 is coupled to pitch drive pinion 78 such that pitch drive pinion 78 is rotated by pitch drive gearbox 76. Pitch bearing 72 is coupled to pitch drive pinion 78 such that rotation of pitch drive pinion 78 causes rotation of pitch bearing 72.

[0049] Pitch drive system 68 is coupled to wind turbine controller 36 to adjust the pitch angle of rotor blades 22 upon receiving one or more signals from wind turbine controller 36. In this example, pitch drive motor 74 is any suitable motor driven by an electrical and / or hydraulic system that enables pitch assembly 66 to function as described herein. Alternatively, pitch assembly 66 may include any suitable structure, configuration, arrangement, and / or components, such as, but not limited to, hydraulic cylinders, springs, and / or servo mechanisms. In certain embodiments, pitch drive motor 74 is driven by the rotational inertia of hub 20 and / or energy extracted from a stored energy source (not shown) that provides energy to components of wind turbine 10.

[0050] Pitch assembly 66 may also include one or more pitch control systems 80 for controlling pitch drive systems 68 according to control signals from wind turbine controller 36 for certain priority conditions and / or during overspeed of rotor 18. In this example, pitch assembly 66 includes at least one pitch control system 80 communicatively coupled to each pitch drive system 68 for controlling pitch drive systems 68 independently from wind turbine controller 36. In this example, pitch control system 80 couples to pitch drive systems 68 and sensors 70. During normal operation of wind turbine 10, wind turbine controller 36 may control pitch drive systems 68 to adjust the pitch angle of rotor blades 22.

[0051] According to one embodiment, a power generator 84, comprising, for example, a battery and an electrical capacitor, is disposed at or within the hub 20 and is coupled to the sensors 70, the pitch control system 80, and the pitch drive system 68 to provide a source of electrical power to these components. In this example, the power generator 84 provides a continuous source of electrical power to the pitch assembly 66 during operation of the wind turbine 10. In an alternative embodiment, the power generator 84 supplies electrical power to the pitch assembly 66 only during a power loss event of the wind turbine 10. A power loss event may include a loss or degradation of the electrical grid, a malfunction of the electrical system of the wind turbine 10, and / or a failure of the wind turbine controller 36. During a power loss event, the power generator 84 operates to supply electrical power to the pitch assembly 66 so that the pitch assembly 66 can operate during the power loss event.

[0052] In this example, pitch drive system 68, sensor 70, pitch control system 80, cables, and power generator 84 are each disposed within a cavity 86 defined by an interior surface 88 of hub 20. In alternative embodiments, the components may be disposed relative to and directly or indirectly coupled to the exterior roof surface of hub 20.

[0053] FIG. 3 is a cross-sectional view of one embodiment of an assembly for a direct-drive wind turbine. The assembly comprises a rotor hub 20, a generator rotor 142 (which together with a corresponding stator obviously forms part of the generator), and a rotatable shaft 57 for supporting the generator rotor 142 on a stationary frame 55. One or more bearings 111 may be provided for rotatably supporting the rotatable shaft 57 (and other rotating components of the wind turbine) on the stationary frame 55. FIG. 3 schematically shows that the assembly further comprises a slip ring unit 200. The slip ring unit 200 comprises a stationary part 202 and a rotating part 201. The stationary part 202 of the slip ring unit 200 is configured to connect to a stationary component of the wind turbine. In this embodiment, the stationary component of the wind turbine is the stationary frame 55. The rotating part 201 of the slip ring unit 200 is configured to connect to a rotating component of the wind turbine. Two different embodiments for connecting the rotating part 201 are shown in FIG. 3. Thus, both a first connection to rotor hub 20 and a second connection to rotatable shaft 57 are shown. Nevertheless, it is understood that in other embodiments, only one of such connections may be provided. Furthermore, in other embodiments, a connection to generator rotor 142 may also be envisioned.

[0054] Brackets or supports 204 may be utilized to connect the stationary part 202 of the slip ring unit 200 to the stationary frame 55, while a torque transmission system 203 is provided to connect the rotating part 201 to the rotating components of the wind turbine, such as the rotor hub 20 and / or the rotatable shaft 57.

[0055] The slip ring unit 200 includes an encoder (not shown) that may be used to sense the position and / or rotational speed of a rotating component of the wind turbine, such as the rotor hub 20, the generator rotor 142, or the rotatable shaft 57. As also shown in Figure 3, the slip ring unit 200 is configured to be mounted along the axis of rotation 30 of the wind turbine 10, and more specifically, the wind turbine rotor. In this manner, the rotor hub 20, the generator rotor 142, the rotatable shaft 57, and the slip ring unit 200 may all include a common axis of rotation 30.

[0056] 4A and 4B show schematically two examples of the mounting of slip ring unit 200 and the main orientations considered in this disclosure. In particular, both figures show a front view of the arrangement of slip ring unit 200, which corresponds to a view from the front end of wind turbine 10.

[0057] The axial direction labeled "A" corresponds to the direction of the rotational axis 30 of the wind turbine rotor 18. Meanwhile, the radial direction labeled "R" corresponds to the direction extending from the center of the rotating part 201 of the slip ring unit 200 along the circumferential radius. In the embodiment of FIG. 4A, the torque transmission system 203 extends in a direction substantially corresponding to the radial direction. Indeed, in such an embodiment, the protrusion of the torque transmission system 203 extends to the center of the slip ring unit 200. FIG. 4B shows various mounting embodiments of the slip ring unit 200. In this embodiment, the main direction of the torque transmission system 203 is not aligned with the radial direction R. Finally, the tangential direction labeled "T" is coplanar with and perpendicular to the radial direction. As shown in FIGS. 4A and 4B, the tangential direction defines the tangent to the circumference along which the rotational motion is indicated. Various reasons, such as the ergonomics or design of the slip ring unit 200, may result in an embodiment like that shown in FIG. 4A or an embodiment like that shown in FIG. 4B. Nevertheless, regardless of the particular orientation of the torque transmission system 203, the definitions of axial (A), radial (R), and tangential (T) directions remain the same.

[0058] According to the present disclosure, the torque transmission system 203 is configured to connect the rotating part 201 of the slip ring unit 200 to the rotating component of the wind turbine while having axial (A) and / or radial (R) degrees of freedom. Furthermore, the torque transmission system 203 is configured to prevent relative displacement in the tangential direction (T) between the rotating part 201 of the slip ring unit 200 and the rotating component of the wind turbine.

[0059] Providing a degree of freedom mitigates the effects of potential changes in radial length between the rotating part 201 of the slip ring unit 200 and the rotating components of the wind turbine during rotation of the wind turbine 10. Such changes can arise from both tolerances and operating loads. Furthermore, relative displacement between the rotating part 201 of the slip ring unit 200 and the wind turbine rotating part can also result from axial displacement of the bearing 111. Such a degree of freedom may be provided by a coupling element.

[0060] In particular, in one embodiment of the present disclosure, the torque transmission system 203 may also have degrees of freedom in the axial and radial directions. Thus, the ability of the torque transmission system 203 to simultaneously absorb radial and axial relative displacements may be advantageous in compensating for multiple simultaneous effects that may induce large stresses in the slip ring unit 200. Thus, radial displacements may result from imperfect circularity or alignment resulting from machining and / or assembly tolerances, while dynamic axial relative displacements may result from loads acting on the wind turbine during operation. Various embodiments of the torque transmission system 203 that provide such degrees of freedom are described below.

[0061] 5 is a detailed diagram of an assembly of a slip ring unit 200 according to one embodiment. In particular, a single support 204 may be provided for connecting the stationary part 202 of the slip ring unit 200, or the slip ring unit 200 may be arranged in a suspended configuration. The support 204 may be fixed to the stationary frame 55 at one or more points (not shown) in the forward region of the stationary frame 55. In this way, the slip ring unit 200 may be positioned near the interface between the stationary frame 55 and a rotating component of the wind turbine, such as the rotor hub 20 or the rotatable shaft 57. This may facilitate connection of the rotating part 201 of the slip ring unit 200.

[0062] As also shown in FIG. 5 , the torque transmission system 203 may be configured to guide one or more cables (not shown) from the rotating portion 201 of the slip ring unit 200. Thus, as shown in FIG. 5 , the torque transmission system 203 includes a tray-shaped transmission arm 207a (or at least a portion of the transmission arm may be tray-shaped), which may be dimensioned to support the weight of one or more cables connecting the rotating portion 201 of the slip ring unit 200 to various components, such as blade pitch actuators or blade sensors. In this manner, convenient and optimal guidance of the cables may be provided without the need for additional components. Depending on the type and size of the cables, various tray supports may be utilized. In particular, when guiding power cables, more rigid tray supports may be utilized than when guiding only data cables.

[0063] FIG. 5 illustrates that the torque transmission system 203, in one embodiment, may include transmission arms 207 a, 207 b and a coupling element 205. First ends of the transmission arms 207 a, 207 b may be configured to connect to a rotating component of the wind turbine. The coupling element 205 may be configured to connect between second ends of the transmission arms 207 a, 207 b and the rotating part 201 of the slip ring unit 200. Such coupling element 205 may be designed and positioned to accommodate one or more degrees of freedom to allow relative axial and / or radial displacement between the rotating part 201 of the slip ring unit 200 and the rotating component of the wind turbine while preventing tangential movement. Various configurations of the coupling element 205 may be envisioned, as described in more detail below with reference to FIGS. 7-10.

[0064] Additionally, in another embodiment (not shown), the torque transmission system 203 may also include a transmission arm and a coupling element, where the coupling element may be configured to connect between a rotating component of the wind turbine and a first end of the transmission arm, and the second end of the transmission arm may be directly connected to the rotating portion of the slip ring unit. As in the previous embodiment, the coupling element may be configured to accommodate relative axial and / or radial displacement while preventing tangential displacement.

[0065] In yet another embodiment, two different coupling elements may be provided: a first coupling element may be configured to connect a rotating component of the wind turbine to a first end of the transmission arm, and a second coupling element may be configured to connect a second end of the transmission arm to the rotating part 201 of the slip ring unit 200. Again, the coupling elements may be configured to accommodate relative axial and / or radial displacement while preventing tangential displacement.

[0066] 5, the transmission arm 207 of the torque transmission system 203 may include multiple portions 207a, 207b. The portions 207a, 207b may be fixedly connected to each other. Thus, in one embodiment, the transmission arm 207 may include a first portion 207a, which may be configured not only as a torque transmission arm but also as a cable tray, and a second portion 207b, which may be shaped to suit the dimensions of various portions, for example, the rotating portion 201 of the slip ring unit 200. In this way, an optimal connection with the slip ring unit 200 may be achieved.

[0067] Figure 6 (top diagram) shows schematically the variation of wind turbine rotational speed 310 as determined by an encoder located on slip ring unit 200 that is not installed in accordance with the present disclosure (i.e., installed in accordance with the prior art). The signal received from the encoder is compared to the rotational speed 300 estimated from the electronic power converter. Figure 6 (bottom diagram) shows the absolute error (in rpm) of the speed 310 as determined by the encoder. As shown in Figure 6, the large vibrations and errors can clearly be seen when installing the slip ring unit according to the prior art.

[0068] In particular, Figure 6 was obtained using a configuration similar to that shown in Figure 5, but with the coupling elements equipped with spherical bearings at both ends. As a result, not only are relative axial and radial displacements permitted, but relative tangential movement is also permitted. Thus, even if such a design is suitable for the simple transfer of power and data signals, the resulting velocity (and position) clearly exhibits undesirable variations.

[0069] Periodic oscillations in the detected speed 310 can be seen in FIG. 6. These periodic oscillations are primarily caused by misalignment between the shaft of the slip ring unit, on which the encoder is mounted and the shaft of the wind turbine rotor, whose frequency matches the rotational speed of the wind turbine rotor. Such misalignment between the shafts can be corrected by placing an elastic coupler in the slip ring unit between the main shaft of the slip ring unit, i.e., the shaft receiving the torque, and the secondary shaft, on which the encoder may be mounted. Such elastic couplers for correcting misalignment between the shafts are known to those skilled in the art, and therefore further technical details will not be provided herein. Specifically, couplers such as bellows couplers, double loop couplers, or helical couplers may be utilized to compensate for the misalignment between the shafts.

[0070] Furthermore, additional random vibrations of small amplitude and high frequency are also observed during the rotation of the wind turbine, which are generated by the relative tangential motion between the rotating part 201 of the slip ring unit 200 and the torque transmission system 203.

[0071] Such oscillations in the detected speed 310 can result in several undesirable effects, including, among others, false overspeed trips, overspeed events not being captured, insufficient rotor position accuracy due to rotor lock, load increase, and / or non-optimal tracking of the power curve. Overall, when using an encoder in the slip ring unit 200, it is not appropriate to provide a coupling element that allows for degrees of freedom in all directions.

[0072] Therefore, as already mentioned above, the disclosed embodiments comprise a torque transmission system 203 that prevents any relative displacement in the tangential direction, i.e., the degrees of freedom are provided in the axial and / or radial directions, but not in the tangential direction. In this way, only torque is transmitted to the rotating part 201 of the slip ring unit 200 by the torque transmission system 203, and high frequency vibrations as shown in FIG. 6 are mitigated.

[0073] 7A-7C schematically illustrate one embodiment of a torque transmission system 203, and more specifically, a coupling element 205, that is configured to provide axial (A) and radial (R) degrees of freedom, but not a tangential (T) degree of freedom. In particular, FIG. 7A schematically illustrates a top view of the assembly, and FIG. 7B illustrates a front view of the assembly. Finally, FIG. 7C illustrates a detailed view of the coupling element 205 itself. It should further be noted that the embodiment illustrated in FIGS. 7A-7C also corresponds to the previously described embodiment illustrated in FIG. 4B. Thus, in this embodiment, the main direction of the torque transmission system 203 is not aligned with the radial direction R, as already described with reference to FIG. 4B or as also illustrated in FIG. 7B.

[0074] In this embodiment, the torque transmission system 203 may include a coupling element 205, which may include a coupling plate 250 configured to connect to the second end of the transmission arm 207. The coupling plate 250 may be configured to slide radially relative to the transmission arm 207. The slidable connection may thus allow radial displacement while preventing any tangential displacement. Thus, the rotation of the rotating portion 201 of the slip ring unit 200, and therefore the slip ring shaft, may substantially coincide with the rotation of the wind turbine rotor. In one embodiment, the coupling plate 250 may be connected to the side wall 201 a of the rotating portion 201 of the slip ring unit 200. A mechanical interface may be provided for this purpose. In embodiments such as those shown in FIGS. 7A-7C, the coupling plate 250 may not be directly connected to the side wall 201 a of the rotating portion 201, but an extension bracket 221 may be utilized to facilitate the connection.

[0075] 7B, to allow radial sliding movement, coupling element 205, and more specifically coupling plate 250, may be attached to an angled surface at the second end of torque arm 207. The angled surface may be such that the plane of coupling plate 250 may be substantially aligned perpendicular to the radial direction R, and thus the tangential direction T. In this way, a degree of freedom may be provided in the radial direction while preventing movement in the tangential direction.

[0076] In an embodiment, the torque transmission system 203 may include one or more fasteners 252 connecting the second end of the transmission arm 207 to the coupling plate 250. The fasteners 252 may be disposed in slots 253 in the coupling plate 250. The slots 253 may extend radially when in an attached state. Alternatively, or additionally, the torque transmission system 203 may include a clevis coupler 254 (or equivalent coupler) connecting the coupling plate 250 to the rotating part 201 of the slip ring unit 200, as also shown in FIGS. 7A-7C . As known to those skilled in the art, a clevis coupler 254 is a mechanical joint typically comprising a U-shaped or fork-shaped part with a hole at the end of the arm through which a pin is inserted. The clevis coupler 254 may be configured to provide a degree of freedom in the axial direction, as can be clearly seen in FIG. 7A . Other types of connections capable of providing such a degree of freedom may also be envisioned in other variations.

[0077] Thus, coupling element 205 may be designed and constructed to allow axial and / or radial movement to a certain extent determined by the size of hole 253 and by the design of clevis coupler 254.

[0078] In particular, coupling plate 250 may include one or more holes 253 for connecting to the second end of transmission arm 207 and a clevis coupler 254 (or equivalent) for connecting to rotating portion 201 of slip ring unit 200. Holes 253 for connecting to the second end of transmission arm 207 may have an elongated shape extending radially, while clevis coupler 254 for connecting to rotating portion 201 of slip ring unit 200 may be configured to provide a degree of freedom in the axial direction. In this particular embodiment, deviations in both the axial and radial directions may be accommodated.

[0079] Additionally, to improve the performance of the system shown in the embodiment of FIGS. 7A-7C, a low-friction element 251 may be disposed between the coupling plate 250 and the second end of the transfer arm 207. Such a low-friction element 251 may be provided to facilitate sliding between the various components. In one embodiment, the low-friction element 251 may comprise a graphite insert. In other embodiments, other low-friction materials may be provided. Furthermore, in other embodiments, the respective surfaces may be surface-treated or lined. In embodiments such as those shown in FIGS. 7A-7C, the coupling plate 250 may not be directly attached to the side wall 201 a of the rotating portion 201, but an extension bracket 221 may be utilized to facilitate the connection.

[0080] Brass may be used for the coupling plate 250 and fasteners 252 due to its corrosion resistance and low friction characteristics.

[0081] 8 schematically illustrates a top view of another embodiment of a torque transmission system 203 including a coupling element 205 that provides degrees of freedom in the axial direction A and the radial direction R, but not in the tangential direction T. In this embodiment, the coupling element 205 may include a first universal joint 351 and a second universal joint 352 connected by a sliding intermediate shaft 353. The first universal joint 351 may be configured to be connected to the second end of the transmission arm 207. The second universal joint 352 may be configured to be connected to the rotating part 201 of the slip ring unit 200, more specifically, to the front wall 201b of the rotating part 201 of the slip ring unit 200, at a location substantially aligned with the axis of rotation of the rotating part 201 of the slip ring unit 200.

[0082] According to this embodiment, a double universal joint, i.e., a first universal joint 351 and a second universal joint 352 connected to the intermediate shaft 353, can provide a uniform speed transmission from the transmission arm 207 to the rotating part 201 of the slip ring unit 200 and, therefore, to the encoder arranged in the slip ring unit 200. As described with reference to FIG. 3 , the rotation axis of the rotating part 201 of the slip ring unit 200 can substantially coincide with the rotation axis 30 of the wind turbine rotor 18. Furthermore, the intermediate shaft 353 can be sliding, for example, telescopic. In other words, the intermediate shaft 353 can adjust its length within certain limits. In this way, the coupling element 205 can be adapted to various relative positions between the rotating part 201 of the slip ring unit 200 and the transmission arm 207 so that relative movements in the axial and radial directions can be allowed.

[0083] In a variation of this embodiment, the first universal joint 351 and the second universal joint 352 may have a 90 degree offset. Also, the angle of the first universal joint 351 relative to the intermediate shaft 353 may be approximately the same as the angle of the second universal joint 352 relative to the intermediate shaft 353. In this configuration, it may be preferable to have a one-to-one relationship between the rotational speeds on either side of the double universal joint, i.e., between the drive transfer arm 207 and the driven rotor 201 of the slip ring unit 200. Thus, an encoder located within the slip ring unit 200 may replicate or match the rotation of a rotating component of the wind turbine connected to the opposite end of the torque transfer system 203.

[0084] 9 schematically illustrates yet another embodiment of the present disclosure. In this embodiment, the torque transmission system 203 may include a coupling element 205 having a first constant velocity universal joint 451 and a second constant velocity universal joint 452 connected by an intermediate shaft 453. The first constant velocity universal joint 451 may be configured to connect to a second end of the transmission arm 207, and the second constant velocity universal joint 452 may be configured to connect to the rotating portion 201 of the slip ring unit 200. In one embodiment, the second constant velocity universal joint 452 may be configured to connect at the front wall 201b at a location substantially aligned with the rotation axis of the rotating portion 201 of the slip ring unit 200. A connection interface 211 may be provided on the rotating portion 201 of the slip ring unit 200 to enable such connection.

[0085] According to this embodiment, the constant velocity universal joints 451, 452 may be configured to not allow relative tangential motion but to accommodate radial and axial length variations. Thus, the angular velocity of the driven shaft, i.e., the shaft of the rotating part 201 of the slip ring unit 200, may match the angular velocity of the drive shaft, i.e., the angular velocity of the transmission arm 207. Similar to the embodiment described with reference to FIG. 8, the two constant velocity universal joints 451, 452 may also be phased relative to each other to provide a uniform transmission of rotational velocity from the first constant velocity universal joint 451 to the second constant velocity universal joint 452.

[0086] 10A-10B illustrate a further embodiment of a torque transmission system 203 according to the present disclosure. In particular, FIG. 10A illustrates an overall top view of the arrangement, while FIG. 10B illustrates a detailed view of a coupling element 205. In this embodiment, the coupling element 205 may include a first leg 551 and a second leg 552. A first end of the first leg 551 may be configured to be fixedly connected to a second end of the transfer arm 207, while a first end of the second leg 552 may be configured to be fixedly connected to the rotating portion 201 of the slip ring unit 200. The second end of the first leg 551 and the second end of the second leg 552 may be connected at a pivot point 555. Fasteners 553, 554 may be used for corresponding connections to the transfer arm 207 and the rotating portion 201 of the slip ring unit 200.

[0087] The pivot point 555 may be configured to move in a plane defined by the axial direction A and the radial direction R, but not in the tangential direction T. Thus, the coupling element 205 may be such that the pivot point 555 may be configured to facilitate relative axial and radial movement between the first end of the first leg 551 and the first end of the second leg 552, while preventing relative movement in the tangential direction. Thus, in this case, only torque may be transmitted by the torque transmission system 203. To improve the robustness of the system, further articulation joints 556 may be added to the system, i.e., in a pantograph-like arrangement.

[0088] 7 to 10 show a coupling element 205 arranged between the rotating part 201 of the slip ring unit 200 and the second end of the transmission arm 207. Nevertheless, it is understood that equivalent systems can be envisaged in which such a coupling element 205 can be arranged between the first end of the transmission arm 207 and a rotating component of the wind turbine. In such embodiments, either a direct connection between the transmission arm 207 and the rotating part 201 of the slip ring unit 200, or a connection via a further coupling element 205, can be envisaged. In all cases, the coupling element 205 can be configured to have degrees of freedom in the axial and / or radial directions while preventing movement in the tangential direction.

[0089] In another aspect of the present disclosure, there may be provided a wind turbine comprising a slip ring unit and a torque transmission system according to any of the preceding embodiments. The wind turbine may be a direct drive wind turbine, and the rotating components of the wind turbine may comprise a rotor hub, a generator rotor, or a rotatable shaft. This aspect of the present disclosure may result in a wind turbine with improved performance and safety by providing reliable and efficient detection of both rotor position and speed.

[0090] In yet another aspect of the present disclosure, there is provided a method 100 for assembling a slip ring unit with an encoder for a wind turbine, particularly a direct drive wind turbine, as shown in the flowchart of Figure 11. The method 100 includes providing a slip ring unit and a torque transmission system at blocks 110 and 120. The method 100 also includes connecting a stationary portion of the slip ring unit to a stationary component of the wind turbine at block 130. The method 100 includes connecting a rotating portion of the slip ring unit to the rotating component of the wind turbine at block 140. Furthermore, connecting the rotating portion of the slip ring unit to the rotating component of the wind turbine includes connecting via the torque transmission system to prevent relative tangential displacement between the rotating portion of the slip ring unit and the rotating component of the wind turbine while providing degrees of freedom in the axial and / or radial directions.

[0091] According to this method 100, a convenient mounting of the slip ring unit is achieved, which allows for accurate determination of the position and rotational speed of the wind turbine rotor while mitigating the effects of system deformations. In particular, providing certain degrees of freedom allows for the accommodation of such deformations, while the restriction of tangential movements results in accurate measurements.

[0092] In one embodiment of the method, the torque transmission system may include a coupling element and a transmission arm having a first end and a second end. Thus, connecting the rotating portion of the slip ring unit to the rotating component of the wind turbine in block 140 may include connecting the first end of the transmission arm to the rotating component of the wind turbine and connecting the coupling element between the second end of the transmission arm and the rotating portion of the slip ring unit. Alternatively, connecting the rotating portion of the slip ring unit to the rotating component of the wind turbine may include connecting the coupling element between the rotating component of the wind turbine and the first end of the transmission arm and connecting the second end of the transmission arm to the rotating portion of the slip ring unit.

[0093] By providing such a coupling element, a highly versatile approach can be achieved. Thus, a substantially conventional transfer arm can be utilized, while the transfer element can be designed with the necessary features to allow the desired degrees of freedom while preventing tangential movement. Such a division between the transfer arm and the coupling element can increase the versatility of the system while facilitating the assembly process.

[0094] In a variation of the method 100, connecting the rotating portion of the slip ring unit via the torque transmission system may include connecting the torque transmission system to a sidewall of the rotating portion of the slip ring unit.

[0095] Mounting the rotating part of the slip ring unit on the side may facilitate connection in certain designs of torque transmission systems. Furthermore, in this variant, the rotating part of the slip ring may comprise a simple external housing with several input / output connectors located on one or more of the walls of the housing.

[0096] In yet another variation of method 100, connecting the rotating portion of the slip ring unit via the torque transmission system may include connecting the torque transmission system to a front wall of the rotating portion of the slip ring unit at a location substantially aligned with the axis of rotation of the rotating portion of the slip ring unit.

[0097] This variant may be particularly useful depending on the nature of the torque transmission system, and more particularly the nature of the coupling element, in which the rotatable shaft of the slip ring unit may be arranged to protrude from the front wall of the rotating part of the slip ring so as to allow connection with the torque transmission system.

[0098] This specification uses examples to disclose the present teachings, including preferred embodiments, and also enables one of ordinary skill in the art to practice the present teachings, including making and using any device or system and performing any incorporated methods. The patentable scope is defined by the claims and may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims. Those skilled in the art will be able to mix and match aspects from the various embodiments described above, as well as other known equivalents for each such aspect, to construct further embodiments and techniques consistent with the principles of the present application. Where reference signs relating to the drawings are placed within parentheses in the claims, these are merely to enhance the clarity of the claims and should not be construed as limiting the scope of the claims. [Explanation of symbols]

[0099] 10. Wind Turbines 12 Ground 14 Support System 15 Tower 16 Nacelle 18 Wind Turbine Rotor 20 rotor hub 22 rotor blades 24 Blade base 26 Load Transfer Area 28 Wind direction 30 Rotor shaft, rotating shaft 32 Pitch System 34 Pitch axis 36 Wind Turbine Controller 38 Yaw axis 40 processors 42 Generator 44 Main shaft, rotor shaft 46 Gearbox 48 High Speed ​​Shaft 50 combiner 52 Main frame, support 54 Separation support means 55 still frames 56 Yaw drive mechanism 57 Rotatable shaft 58 Weather Measurement System 60 Main forward support bearing 62 Main rear support bearing 64 Drivetrain 66 Pitch Assembly 68 Pitch Drive System 70 sensors 72 Pitch bearing 74 Pitch drive motor 76 Pitch drive gearbox 78 Pitch drive pinion 80 Pitch Control System 84 Electric Power Generator 86 Cavity 88 Inner 90 Transformer 103 Torque arm 110 blocks 111 Bearings 120 blocks 130 blocks 140 blocks 142 Generator rotor 200 slip ring unit 201 Driven rotating part, rotating part 201a side wall 201b front wall 202 Stationary part 203 Torque Transmission System 204 Brackets or supports 205 Bonding Elements 207 Drive transmission arm, torque arm 207a Tray-shaped transfer arm, first part 207b Transmission arm, second part 211 Connection Interface 221 Extension bracket 250 Binding Plate 251 Low friction elements 252 Fasteners 253 long hole 254 Clevis Coupler 300 rotation speed 310 Wind Turbine Rotational Speed 351 First Universal Joint 352 Second Universal Joint 353 Sliding intermediate shaft 451 First constant velocity universal joint 452 Second constant velocity universal joint 453 Intermediate shaft 551 First Leg 552 Second Leg 553 Fasteners 554 Fasteners 555 pivot point 556 Joints

Claims

1. A torque transmission system (203) for a slip ring unit (200) of a wind turbine (10), the slip ring unit (200) being configured to be mounted along a rotation axis (30) of a wind turbine rotor (18) and comprising: an encoder; a rotating part (201) configured to connect to a rotating component of the wind turbine (10); and a stationary part (202) configured to connect to a stationary component of the wind turbine (10); the torque transmission system (203) is configured to connect the rotating part (201) of the slip ring unit (200) to the rotating component of the wind turbine (10) and has axial and / or radial degrees of freedom; The torque transmission system (203) is further configured to prevent relative tangential displacement between the rotating part (201) of the slip ring unit (200) and the rotating component of the wind turbine (10).

2. The torque transmission system (203) of claim 1, wherein the torque transmission system (203) also has degrees of freedom in the axial and radial directions.

3. 3. The torque transmission system (203) of claim 1 or 2, comprising a transmission arm (207) and a coupling element (205), wherein a first end of the transmission arm (207) is configured to connect to the rotating component of the wind turbine (10), and the coupling element (205) is configured to connect between a second end of the transmission arm (207) and the rotating part (201) of the slip ring unit (200).

4. 4. The torque transmission system (203) of claim 3, wherein the coupling element (205) comprises a coupling plate (250) configured to connect to the second end of the transmission arm (207), the coupling plate (250) configured to slide radially relative to the transmission arm (207).

5. 5. The torque transmission system of claim 4, further comprising one or more fasteners connecting the second end of the transmission arm to the connecting plate, the fasteners being disposed in slots in the connecting plate, the slots extending along the radial direction when in an installed state.

6. 6. The torque transmission system (203) of claim 4 or 5, wherein the coupling element (205) comprises a clevis coupler (254) for connection to the rotating part (201) of the slip ring unit (200), the clevis coupler (254) exhibiting a degree of freedom in the axial direction.

7. 4. The torque transmission system (203) of claim 3, wherein the coupling element (205) comprises a first universal joint (351) and a second universal joint (352) connected by a sliding intermediate shaft (353), the first universal joint (351) configured to connect to the second end of the transmission arm (207), and the second universal joint (352) configured to connect to the rotating part (201) of the slip ring unit (200).

8. 8. The torque transmission system (203) of claim 7, wherein the first universal joint (351) and the second universal joint (352) have a 90 degree offset, and further wherein an angle of the first universal joint (351) relative to the intermediate shaft (353) is substantially the same as an angle of the second universal joint (352) relative to the intermediate shaft (353).

9. 4. The torque transmission system (203) of claim 3, wherein the coupling element (205) comprises a first constant velocity universal joint (451) and a second constant velocity universal joint (452) connected by an intermediate shaft (453), the first constant velocity universal joint (451) configured to connect to the second end of the transmission arm (207), and the second constant velocity universal joint (452) configured to connect to the rotating part (201) of the slip ring unit (200).

10. 4. The torque transmission system (203) of claim 3, wherein the coupling element (205) comprises a first leg (551) and a second leg (552), a first end of the first leg (551) configured to be fixedly connected to the second end of the transmission arm (207), a first end of the second leg (552) configured to be fixedly connected to the rotating part (201) of the slip ring unit (200), and the second end of the first leg (551) and the second end of the second leg (552) are connected at a pivot point (555).

11. 11. The torque transmission system (203) of claim 10, wherein the pivot point (555) is configured to facilitate relative axial and radial movement between the first end of the first leg (551) and the first end of the second leg (552) while preventing relative tangential movement.

12. 12. A wind turbine (10) comprising a slip ring unit (200) and a torque transmission system (203) according to any one of claims 1 to 11, wherein the wind turbine (10) is a direct drive wind turbine and the rotating components of the wind turbine (10) comprise a rotor hub (20), a generator rotor (142), or a rotatable shaft (57).

13. A method (100) of assembling a slip ring unit (200) with an encoder in a wind turbine (10), said method (100) comprising: providing (110) the slip ring unit (200); providing (120) a torque transmission system (203); connecting (130) a stationary part (202) of the slip ring unit (200) to a stationary component of the wind turbine (10); connecting (140) a rotating part (201) of said slip ring unit (200) to a rotating component of said wind turbine (10); Including, 1. The method of claim 100, wherein connecting the rotating part of the slip ring unit to the rotating component of the wind turbine comprises connecting the rotating part of the slip ring unit to the rotating component of the wind turbine via the torque transmission system in a manner that prevents relative tangential displacement between the rotating part of the slip ring unit and the rotating component of the wind turbine while providing axial and / or radial degrees of freedom.

14. The torque transmission system (203) comprises a coupling element (205) and a transmission arm (207) having a first end and a second end, and the step (140) of connecting the rotating part (201) of the slip ring unit (200) to the rotating component of the wind turbine (10) comprises: connecting the first end of the transmission arm (207) to the rotating component of the wind turbine (10) and connecting the coupling element (205) between the second end of the transmission arm (207) and the rotating part (201) of the slip ring unit (200); or 14. The method (100) of claim 13, comprising connecting the coupling element (205) between the rotating component of the wind turbine (10) and the first end of the transmission arm (207), and connecting the second end of the transmission arm (207) to the rotating part (201) of the slip ring unit (200).

15. connecting the rotating part (201) of the slip ring unit (200) via the torque transmission system (203) comprises connecting the torque transmission system (203) to a side wall (201 a) of the rotating part (201) of the slip ring unit (200); or 15. The method (100) according to claim 13 or 14, wherein the step of connecting the rotating part (201) of the slip ring unit (200) via the torque transmission system (203) comprises connecting the torque transmission system (203) to a front wall (201b) of the rotating part (201) of the slip ring unit (200) at a position substantially aligned with a rotation axis of the rotating part (201) of the slip ring unit (200).

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