Power train assembly for a wind turbine

Abstract

A wind turbine nacelle includes an outer casing defining an internal volume housing a powertrain assembly, the powertrain assembly including: a gearbox including an input shaft and an output shaft aligned on a common axis of rotation; and a generator connected to the output shaft of the gearbox. The generator includes a generator cabinet surrounding a stator in a radially outward position and a rotor in a radially inward position within an internal chamber, the rotor being rotatable about a common axis of rotation. The rotor includes: a cylindrical field structure coupled to a rotor support frame; and a gearbox connecting flange coupled to the gearbox output shaft via a first fixed array; wherein the generator cabinet has an opening allowing maintenance personnel full access to the internal chamber, and wherein the internal chamber is configured to allow maintenance personnel to access the first fixed array connecting the gearbox output shaft to the gearbox connecting flange from at least a position fully within the internal chamber.

Description

Technical Field

[0001] This invention relates to a power system component, and more particularly to a wind turbine. Background Technology

[0002] Wind turbines use a large rotor with multiple rotor blades to convert the kinetic energy from the wind into electrical energy. A typical horizontal axis wind turbine (HAWT) consists of a tower, a nacelle at the top of the tower, a rotor hub mounted to the nacelle, and multiple wind turbine rotor blades connected to the hub. Depending on the wind direction, the nacelle and rotor blades are steered and oriented to an optimal direction by a yaw system for rotating the nacelle and a pitch system for rotating the blades.

[0003] The nacelle houses many of the functional components of a wind turbine, including, for example, the main rotor shaft, gearbox, and generator, as well as converter devices for converting mechanical energy at the rotor into electrical energy to supply the power grid. The gearbox increases the speed of the low-speed main shaft and drives the gearbox output shaft. The gearbox output shaft, in turn, drives the generator, which converts the rotation of the gearbox output shaft into electricity. The electricity generated by the generator can then be converted as needed before being supplied to appropriate consumers (e.g., a power grid distribution system). So-called "direct-drive" wind turbines, which do not use a gearbox, are also known. In a direct-drive wind turbine, the generator is directly driven by the main rotor shaft.

[0004] Typically, the generator of a wind turbine is an IPM (Internal Permanent Magnet) motor, consisting of an outer stator assembly surrounding an internal rotor assembly. The IPM internal rotor assembly usually comprises a ring-shaped structure including multiple ring-shaped permanent magnet packages supported on a central shaft. The gearbox output shaft engages with the central shaft of the rotor assembly.

[0005] WO2020143888A1 illustrates a specific type of IPM motor used as a generator in a wind turbine. In this example, the annular structure is supported at one end by an annular support frame. The absence of a central hub in the rotor assembly results in many important benefits, such as reduced cost and weight, and improved cooling airflow. Cooling air supplied to the generator at the center can flow freely in both the axial and radial directions, effectively cooling the rotor and any generator components located directly nearby. However, further improvements to this design are desired, for example, to enhance the maintainability of the components.

[0006] One object of the present invention is to provide a solution to one or more of the above-mentioned problems. Summary of the Invention

[0007] According to a first aspect of the invention, a wind turbine nacelle is provided, the nacelle comprising an outer casing defining an internal volume, the internal volume housing a powertrain assembly, the powertrain assembly comprising: a gearbox including an input shaft and an output shaft aligned on a common axis of rotation; a generator connected to the output shaft of the gearbox, wherein the generator includes a generator cabinet surrounding a stator in a radially outward position and a rotor in a radially inward position within an internal cavity, the rotor being rotatable about the common axis of rotation. The rotor includes: a cylindrical field structure coupled to a rotor support frame; a gearbox connecting flange coupled to the gearbox output shaft via a first fixed array; wherein the generator cabinet is provided with an opening allowing maintenance personnel full access to the internal cavity, and wherein the internal cavity is configured to allow maintenance personnel to approach the first fixed array coupling the gearbox output shaft to the gearbox connecting flange from at least a position fully within the internal cavity.

[0008] The advantage of this invention is that the powertrain assembly includes a gearbox coupled to a generator, which is specifically configured to facilitate the maintenance process. Typically, powertrain systems including a gearbox coupled to a generator require all maintenance to be performed from an external access point to the generator. However, in the powertrain assembly of this invention, the generator cabinet defines an internal chamber into which maintenance technicians can climb to access various components of the generator system from a position entirely within the generator cabinet. This means that access to components from the outside of the generator is unnecessary, as complete access is possible when the maintenance personnel's entire body is inside the internal chamber. This is impossible in known systems.

[0009] In one embodiment, the gearbox is a planetary gearbox with at least two stages. This provides a particularly space-efficient system where the gearbox and generator are located in the same straight line.

[0010] In addition to the first fixed array, the internal chamber can be configured to allow maintenance personnel full access to other components from the inside, such as: the second fixed array that connects the gearbox connecting flange to the rotor support frame, the tie rod system, the rotor balancing mass block, and the drive ring gear.

[0011] Usefully, the rotor inner diameter defined by the cylindrical field structure can be greater than 2m or even greater than 2.2m to provide space for maintenance personnel.

[0012] The generator cabinet and rotor can be advantageously configured to maximize internal space for maintenance personnel. For example, the rotor connecting flange of the rotor support frame can be spaced apart from the gearbox connecting flange along the axis of rotation by a distance that is at least 25% of the maximum outer diameter of the rotor support frame; the gearbox connecting flange can define a first diameter, and the tie rod system can define a second diameter, wherein the first diameter is smaller than the second diameter, wherein the first diameter can be less than 0.7 m, and wherein the second diameter can be greater than 2 m, and wherein the distance between the rotor connecting flange of the rotor support frame and the gearbox connecting flange along the axis of rotation is between 20% and 60% of the inner diameter of the rotor connecting flange, and preferably between 20% and 40%.

[0013] In one embodiment, the rotor support frame may define access holes. These holes are particularly useful for components accessing the outside of the rotor support frame. For example, the access holes may provide passage through them to at least one of the following generator features: i) stray current protection system; ii) one or more rotation sensor components associated with the gearbox output shaft; iii) accelerometer system; iv) temperature sensor; v) pitch tube seal component. In a preferred embodiment, the passage through the holes may be implemented as at least two, and at least three, of the aforementioned features.

[0014] This invention covers wind turbines including the tower and nacelle as described above.

[0015] The present invention also relates to a method for servicing a wind turbine powertrain in a wind turbine nacelle, wherein the powertrain includes: a gearbox including an input shaft and an output shaft aligned on a common axis of rotation; and a generator connected to the output shaft of the gearbox, wherein the generator includes a generator cabinet defining an internal chamber allowing maintenance personnel access to the interior of the generator cabinet, the generator cabinet surrounding a stator in a radially outward position and a rotor in a radially inward position, the rotor being rotatable about the common axis of rotation, wherein the rotor includes a cylindrical field structure coupled to a rotor support frame, and a gearbox connecting flange coupled to the gearbox output shaft via a first fixed array; and wherein the internal chamber allows maintenance personnel access to the interior of the generator cabinet. The method includes: entering the internal chamber of the generator through an opening defined by the generator cabinet; and performing maintenance operations from a position completely inside the internal chamber.

[0016] In a particularly advantageous aspect, maintenance operations may include maintenance by maintenance personnel from a position entirely within the internal cavity of at least one of the following: i) connecting the gearbox connecting flange to a second fixed array of the rotor support frame; ii) connecting the rotor support frame to a tie rod system of the cylindrical field structure; iii) a plurality of balancing mass blocks configured to provide rotational balance to the cylindrical field structure; and iv) driving the ring gear.

[0017] The generator cabinet may be equipped with one or more closure elements configured to selectively close openings to the internal chambers defined by the generator maintenance cabinet. This results in a normally closed environment for maintenance purposes, accessible to maintenance engineers when necessary. A suitable access control system can be associated with the closure to ensure access is only permitted under safe conditions. Therefore, the closed environment means that the maintenance area can be more easily kept uncontaminated. Attached Figure Description

[0018] The invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0019] Figure 1 This is a front view schematic diagram showing the structure of a known wind turbine;

[0020] Figure 2 It can be accommodated in Figure 1 A view of exemplary powertrain components in the nacelle of a wind turbine.

[0021] Figure 3 It is a cross-sectional view of a known structure including a generator connected to a gearbox, shown in an axially spaced position;

[0022] Figure 4 This is seen from its non-driver side. Figure 3 A perspective view of the generator rotor assembly of a known generator;

[0023] Figure 5 yes Figure 4 The diagram shows a perspective view of the rotor assembly, but from the drive end.

[0024] Figure 6 This is a longitudinal sectional view of a generator rotor assembly according to an embodiment of the present invention, shown schematically from inside the generator maintenance cabinet. The generator rotor assembly includes a cylindrical field structure that mates with a rotor support hub or frame, and can be used in a generator as shown in the previous figures;

[0025] Figure 7 yes Figure 6 A perspective view of the generator rotor assembly, which is isolated from the generator maintenance cabinet;

[0026] Figure 8 yes Figure 6 Another front perspective view of the generator rotor assembly, but omitting the cylindrical field structure;

[0027] Figure 9 This was observed from its non-driving end. Figure 7 A perspective view of the generator rotor assembly;

[0028] Figure 10 yes Figures 6 to 9 An end view of the generator rotor assembly inside its respective generator cabinet shows a maintenance engineer standing inside the support frame to access the internal components; and

[0029] Figure 11a and Figure 11b They respectively showed the same as Figure 10 Similar end views, but with entrance doors in closed and open states respectively. Detailed Implementation

[0030] Specific embodiments of the invention will now be described in detail, with numerous features discussed in detail to provide a thorough understanding of the inventive concept as defined in the claims. However, it will be apparent to those skilled in the art that the invention can be practiced without specific details, and in some cases, well-known methods, techniques, and structures have not been described in detail to avoid unnecessarily obscuring the invention.

[0031] This invention generally relates to a generator configuration that offers several advantages related to the maintainability of the generator and its associated gearbox. In particular, the generator configuration provides improved access for maintenance engineers to the generator's interior, enabling various types of adjustments to be made without disassembling some or all of the generator—a significant advantage in the realm of wind turbine nacelles.

[0032] In order to place the embodiments of the present invention in a suitable context, references will first be made to... Figure 1 The image illustrates a typical horizontal axis wind turbine (HAWT) in which a generator rotor assembly according to embodiments of the invention can be implemented. Although this particular image depicts an onshore wind turbine, it should be understood that equivalent features will also be used for offshore wind turbines. Furthermore, although the wind turbine is referred to as "horizontal axis," those skilled in the art will understand that for practical purposes, the axis is typically slightly tilted to prevent contact between the rotor blades and the wind turbine tower in strong winds.

[0033] The wind turbine 1 includes a tower 2, a nacelle 4 rotatably connected to the top of the tower 2 via a yaw system, a rotor hub 8 mounted to the nacelle 4, and multiple wind turbine rotor blades 10 connected to the rotor hub 8. The nacelle 4 and the rotor blades 10 are rotated by the yaw system and guided to the wind direction.

[0034] The nacelle 4 houses many of the functional components of the wind turbine, including the generator, gearbox, and rotor braking assembly, as well as converter equipment for converting the mechanical energy of the wind into electrical energy to supply the power grid. Figure 2 An example layout within nacelle 4 is shown, comprising a main shaft 26 extending through a main bearing housing 20, a gearbox 22, and a generator 24. The main shaft 26 is connected to and driven by the rotor 8, providing input drive to the gearbox 22. These components can collectively be considered the powertrain of a wind turbine. The gearbox 22 progressively increases the speed of the low-speed main shaft via internal gears (not shown) and drives the gearbox output shaft. The gearbox output shaft, in turn, drives the generator 24, which converts the rotation of the gearbox output shaft into electricity. The electricity generated by the generator 24 can then be converted as needed by other components (not shown) before being supplied to appropriate consumers (e.g., a power grid distribution system).

[0035] The gearbox 22 and the generator 24 can be connected together to form an integrated unit. Figure 3 The generator 24 is shown in more detail. Referring first to the gearbox 22, the gearbox housing is generally cylindrical in shape due to the specific type of gearbox used in the illustrated embodiment, which is a rotary gearbox. As those skilled in the art will know, a rotary gearbox comprises a series of planetary gears arranged around a central sun gear, and they are collectively arranged within a ring gear. The general configuration of the gearbox is such that the input and output shafts are arranged on a common axis. The gear ratio between the ring gear, planetary gears, and sun gear determines the gear ratio of the gearbox. For clarity, the details of the gearbox will not be described in detail here, as the gearbox is not the main subject of the invention. It will only be noted that other gearbox configurations may also be used, although rotary gearboxes are currently envisioned as providing an elegant solution for the range of wind turbine nacelles. Such a rotary gearbox may contain more than one rotary stage, for example, one, two, or three rotary gear stages.

[0036] Still referencing Figure 3 The sectional view, but also referencing Figure 4 and Figure 5Generator 24 is an IPM (Internal Permanent Magnet) motor with an external stator assembly 30 surrounding an internal rotor assembly 32. The stator assembly 30 includes stator windings 38, a stator core 40, and a stator frame (not shown) surrounding and supporting the stator windings 38 and the stator core 40. However, it should be noted that the invention is not limited to a specific type of stator. It is worth noting that... Figure 3 The internal configuration of the generator 24 shown is provided here as an example, and the invention is given in the appropriate context. Figures 3 to 5 The specific construction of the generator rotor 32 is not part of this invention, but is provided for a better understanding of the construction of the generator rotor according to embodiments of the invention, as will be referred to later. Figures 6 to 1 As described in 1.

[0037] The gearbox 22 is connected to the generator 24 via the output shaft 31 of the rotor assembly 32. Therefore, the main shaft of the gearbox output shaft 31 defines the axis of rotation of the generator 24. Notably, the gearbox also includes an input shaft 33 coaxially aligned with the gearbox output shaft 31. Although the generator rotor assembly 32... Figure 3 The cross-section is shown inside generator 22, but it is within... Figure 4 and Figure 5 It is shown separately in the text.

[0038] The generator rotor assembly 32 has a drive end 34 and a non-drive end 36. The drive end 34 faces the gearbox 22, and the non-drive end 36 faces away from the gearbox 22. The non-drive end 36 of the generator rotor assembly 32 can... Figure 4 As seen in the image, the drive end 34 of the generator rotor assembly 32 can... Figure 5 I saw it in the middle.

[0039] The generator rotor assembly 32 includes a cylindrical ring structure 40 defining a hollow central region and arranged to rotate about an axis of rotation. The cylindrical ring structure 40 includes a plurality of solid circular rotor bars 42 housing permanent magnet packages. Thus, the ring structure 40 is responsible for generating the rotating magnetic field of the generator during use. Here, the bars 42 are shown to have equal circumference and thickness, but these can vary. The bars 42 are arranged coaxially about the axis of rotation such that, when assembled, the arrangement of the bars 42 defines a cylindrical structure with a central hollow region. The bars 42 are spaced at equal distances, defining a gap between each pair of bars 42. These gaps allow airflow supplied to the generator at the center through the rotor structure and cooling the generator rotor assembly and other parts of the generator, including components located radially outside the rotor assembly 32. This airflow is further enhanced by the fact that a central hub is not required to provide structure and support for the rotor assembly 32.

[0040] A cylindrical ring structure 40 is connected to a rotor support frame 50. The rotor support frame 50 includes... Figure 4 The best visible radial outer first connecting flange 52 and in Figure 5 The best visible radially inner second connecting flange 54. The first connecting flange 52 is used to connect the bar 42 to the rotor support frame 50 and can therefore be considered a "rotor connecting flange," while the second connecting flange 54 is used to connect the rotor support frame 50 to the gearbox output shaft 31 and can therefore be considered a "gearbox connecting flange." Figure 5 In the image, a set of connecting bolts 56 can be seen extending vertically from the second connecting flange 54, which will be used to secure the support frame 50 to the gearbox output shaft 31.

[0041] The support frame 50 and the cylindrical ring structure 40 are connected by multiple tie rods 58 (in Figure 4 and Figure 5 (Only two of them are identified in the text) are connected together, and the plurality of tie rods 58 extend axially through corresponding holes in the strip 42 and are secured by the rotor connecting flange 52 of the support frame 50. Suitable mechanical fasteners (such as bolts) are provided at the end of each tie rod 58 and are tightened to compress the encapsulation of the strip 42, thereby firmly securing the cylindrical ring structure 40 to the support frame 50 as an integral unit.

[0042] It should be noted that the rotor connecting flange 52 and the gearbox connecting flange 54 are axially oriented surfaces and extend in corresponding planes parallel to but spaced apart from each other along the rotor axis. In this respect, the gearbox connecting flange 54 extends slightly into the hollow internal region defined by the cylindrical ring structure. Furthermore, the circumference of the gearbox connecting flange 54 is smaller than that of the rotor connecting flange 52.

[0043] The support frame 50 also includes a transition section 60 extending between the rotor connecting flange 52 and the gearbox connecting flange 54. The transition section 60 is generally truncated conical and extends at a steep angle relative to the rotor axis. As shown here, the transition section 60 defines an angle of approximately 70 to 80 degrees relative to the rotor axis. In other words, the transition section 60 has a cone angle of approximately 140 to 160 degrees.

[0044] When the generator is assembled, the generator rotor assembly 32 is surrounded by the outer stator 30. Furthermore, both the rotor assembly 32 and the stator 30 are enclosed by the generator housing or cabinet 68, which can be... Figure 3 To understand it best.

[0045] Referring to the known construction of the generator rotor assembly 32 as described above, it should be understood that this construction offers various advantages in terms of generator design and efficiency, but also presents challenges. For example, access to the generator's interior is restricted, making it difficult for maintenance engineers to enter the generator to inspect internal components and take remedial measures when necessary.

[0046] Embodiments of the present invention relate to an improved construction of a generator rotor assembly that addresses these problems. Embodiments of the invention will now be described with reference to the remaining figures.

[0047] The illustrated embodiment provides a generator rotor assembly 70, which is functionally equivalent to the known construction of the generator rotor assembly 32 described above. However, embodiments of the invention offer several advantages, which will be explained in further detail herein.

[0048] Figure 6 A partial schematic diagram of the generator rotor assembly 70 relative to the surrounding components of the generator housing or "cabinet" 81 is shown. Figures 7 to 9 The generator rotor assembly 70 is shown isolated from the generator cabinet 81. It should be noted that the generator rotor assembly 70 of the illustrated embodiment shares many similarities with the rotor assemblies discussed previously; therefore, the focus here will be solely on the differences.

[0049] In a broader sense, the generator rotor assembly 70 includes a rotor support frame 72 that supports a cylindrical field structure 74, which serves as a magnet carrier, thereby generating a rotating magnetic field during use. The configuration and reference of the cylindrical field structure 74 are as follows. Figures 3 to 5 The configuration described is fairly standard, so further detailed discussion of this component will be omitted.

[0050] The generator rotor assembly 70 includes a drive end 76 and a non-drive end 78. The drive end 76 is connectable to the output drive shaft 77 of the gearbox 22, and the non-drive end 78 is located away from the gearbox 22. In practice, the generator rotor assembly 70 can be considered to be rotatably suspended from the gearbox output shaft 77 in a cantilevered manner, since the non-drive end is not rotatably supported by bearings.

[0051] Essentially, the rotor support frame 72 provides a means of connecting the gearbox output shaft 77 to the cylindrical field structure 74. For this purpose, the rotor support frame 72 includes a gearbox connecting flange 80 and a rotor connecting flange 82.

[0052] Both the gearbox connecting flange 80 and the rotor connecting flange 82 are axially oriented surfaces, oriented perpendicular to the rotation axis R of the generator rotor assembly 70 and spaced apart from each other along this axis. In the illustrated embodiment, the two flanges 80, 82 thus extend in a plane perpendicular to the rotation axis R.

[0053] The gearbox connecting flange 80 includes an annular retaining groove configuration 84, through which the rotor support frame 70 can be connected to the gearbox output shaft 77 by a set of suitable bolts (not shown). Therefore, the retaining groove configuration 84 defines the first segment circle diameter, which in Figure 10 It is shown as "D1".

[0054] The rotor connecting flange 82 is coaxial with the gearbox connecting flange 80, and the rotor connecting flange 82 has a larger diameter. The rotor connecting flange 82 is secured to the cylindrical field structure 74 by means of a tie rod system 86, which includes a plurality of circumferentially spaced tie rods 88 extending through the various bars of the cylindrical field structure 74, as in the previous embodiment. Therefore, the circular configuration of the tie rods 88 defines the diameter of the second section circle, such as... Figure 6 As shown in D2, the diameter of the first section circle is smaller than the diameter of the second section circle, D2. In the illustrated embodiment, the diameter of the first section circle, D1, is approximately 30% of the diameter of the second section circle, D2.

[0055] Conveniently, the tie rod system 86 includes a balancing device to adjust the rotational balance of the cylindrical field structure 74. The balancing device can be implemented by adding shims or washers, which can be secured between the rotor connecting flange 82 and the tie rod fastener 89 (e.g., a hex nut). Tensioning of the tie rods 88 can be achieved by properly rotating the corresponding fastener 89, which applies compressive force to the cylindrical structure 74, while adjustment of the rotational balance can be achieved by adding or removing balancing shims around the array of tie rods 88 until optimal rotational balance is obtained.

[0056] The transition section 90 extends between the gearbox connecting flange 80 and the rotor connecting flange 82. The function of the transition section 90 is to provide rigidity to the rotor support frame 72, while maintaining the rotor connecting flange 82 and the gearbox connecting flange 80 in a spaced relationship and promoting good airflow through the structure.

[0057] As can be easily observed from the figure, the transition section 90 comprises two main parts: a first truncated conical portion 92 and a second axially facing surface portion 94. The truncated conical portion 92 is located near the rotor connecting flange 82, and the axially facing surface portion 94 is located near the gearbox connecting flange 80.

[0058] The truncated conical portion 92 includes a plurality of relatively flat regions 96 (not all regions are labeled in the figures for clarity) because they are oriented at a small angle relative to the axis of rotation. Since each region 96 extends axially at a relatively small angle relative to the axis of rotation, they provide areas suitable for maintenance engineers to support the interior of the rotor support frame 72. Therefore, each region 96 can be considered a stepping area. In the illustrated embodiment, there are a total of nine stepping areas 96.

[0059] Each pedaling area 96 is demarcated from its adjacent area by reinforcing ribs or webs 98. The reinforcing ribs 98 contribute to the rigidity of the transition section. Here, the pedaling area 96 is implemented as a relatively thin plate-like portion.

[0060] At this point, it should be understood that although the illustrated embodiment includes multiple trampling areas 96, this is not necessary, but rather the transition section 90 can define any number of trampling areas, which only includes a single continuous trampling area defining a curved surface that extends substantially uninterruptedly circumferentially around the transition section 90.

[0061] As can be seen in Figure 11, the foothold area 96 provides an advantageously stable surface or platform, flat enough to support the maintenance engineer located within the internal chamber 97, which is surrounded by the rotor support frame 72 and thus also by the generator cabinet 81. This aspect also benefits from various other aspects of the rotor support frame, particularly its internal dimensions. For example, the inner diameter of the rotor connecting flange is greater than 1.8 m, but can be greater than 2.0 m or even 2.2 m. This provides a suitable headroom for the maintenance engineer within the rotor support frame 72. (Observation...) Figures 3 to 5 This aspect can be further understood through the transition section 60, which defines a steeper angle relative to the axis of rotation, thus limiting the dimensions of the space inside the rotor assembly. Furthermore, the steep surface presented by the transition section 60 would make it impossible for maintenance engineers to stand comfortably or safely.

[0062] Another advantageous aspect of the rotor support frame 72 is the axial dimension between the rotor connecting flange 82 and the gearbox connecting flange 80. In the illustrated embodiment, the dimension marked "A" (see...) Figure 6 The dimension A indicates the length along the axis of rotation between the rotor connecting flange 82 and the gearbox connecting flange 80. Dimension A is preferably greater than 0.5 m to provide a useful "depth" within the internal cavity 97 of the rotor support frame 72 to fully accommodate maintenance personnel. Still preferably, dimension A is greater than 0.6 m.

[0063] The depth of the internal chamber 97 of the rotor support frame 72 also benefits from the small angle of the foot pedal area 96. For example... Figure 6 As shown, the stepping area 96 is defined at an angle of less than 30 degrees relative to a line parallel to the axis of rotation. This angle is... Figure 6 The term is represented by "B". In other words, the transition section 90 defines a cone angle of less than 60 degrees. The small angle defined by the truncated conical section and the rotor axis R contributes to the depth of the internal chamber 97 of the cylindrical field structure 74.

[0064] As described above, due to the internal dimensions of the rotor support frame 70, specifically its internal volume 97, its inner diameter, and its depth "A", maintenance engineers are able to climb inside and access its various components and other parts associated with the generator. This is a significant advantage, as it means a substantial improvement in the maintainability of the generator.

[0065] In addition to defining the pedaling area 96, the transition section 90 also includes an axially oriented surface portion 94. When the outer surface of the transition section 90 rotates approximately 90 degrees, the axially oriented surface portion 94 defines the drive end 76 of the transition section 90 to provide a flat end face substantially perpendicular to the axis of rotation R. Advantageously, a reinforcing rib 98 extends along the pedaling area 96 in a direction aligned with the axis of rotation and spans between the pedaling area 96 and the axially oriented surface portion 94.

[0066] The axially facing surface portion 94 is provided with an array of entry holes 100 extending to a depth penetrating the axially facing surface portion 94.

[0067] In this embodiment, the entry holes 100 are arranged in a circular array and are equally spaced at an angle. In the illustrated embodiment, there are a total of nine entry holes 100, arranged such that each pedal area 96 has one entry hole. The circular array of entry holes 100 is radially inward of the pedal area 96 and radially outward of the gearbox connecting flange 80. In this sense, it can be considered to be radially located between the gearbox connecting flange 80 and the pedal area 96.

[0068] Access holes 100 allow entry through the rotor support frame 72, enabling maintenance engineers to perform a range of tasks, such as monitoring components of the gearbox output shaft, including bearing sensors (temperature sensors and accelerometers) and rotary encoders. For this purpose, the access holes should have a suitable cross-sectional area to allow maintenance engineers to extend their hands through one of the holes and reach the desired location. Therefore, it is envisioned that each access hole should provide at least 100 cm... 2 The opening area. Optionally, a larger size will be beneficial, such as at least 200 cm². 2 This is because it will provide a larger through area while allowing for improved visibility of the through holes.

[0069] Although the rotor support frame 70 serves as a single component to connect the gearbox output shaft and the cylindrical field structure 74 and transmit drive from the gearbox output shaft to the cylindrical field structure 74, in the illustrated embodiment, the rotor support frame 72 includes at least first and second components, referred to herein as 102 and 104, respectively. Optionally, these components can be cast, for example, with steel of a suitable grade. The first component 102 is radially inside the second component, and the two components together serve as the hub of the cylindrical field structure 74. Therefore, the first component 102 can be considered as the "inner hub component" 102, and the second component 104 can thus be considered as the "outer hub component" 104.

[0070] As shown in the figure, the gearbox connecting flange 80 is part of the inner hub component 102, separate from the outer hub component 104 that defines the transition section 90 and the rotor connecting flange 82. The two components 102 and 104 are connected at a circular array 106 of bolts located radially outward of the inlet hole 100. Notably, the circular array 106 has... Figure 6 The pitch circle diameter is marked D3. The pitch circle diameter D3 of the circular array 106 is larger than the pitch circle diameter D1 of the fixed array 84. Manufacturing the rotor support frame 7 from at least two components in this way provides manufacturing advantages. Furthermore, this configuration allows for easy access to components associated with the generator. For example, with the rotor assembly 70 locked to prevent rotation and radial movement, the inner hub assembly 102 can be removed from the rotor support frame 72. Therefore, the inner hub assembly 102 can be removed from the gearbox by removing the circular array 84 of bolts that connect the rotor support frame 72 to the gearbox output shaft 77, which allows access, maintenance, and removal / replacement of the bearing housing (not shown) associated with the gearbox 22 without requiring complete disassembly of the generator.

[0071] The rotor support frame 72 also includes an extension 110. The extension 110 extends from the outer edge of the non-drive side of the rotor connecting flange 82 and is cylindrical. The axial dimension of the extension 110 is approximately half the axial length of the cylindrical field structure 74. In the illustrated embodiment, the extension 110 is in the form of a thin-walled cylinder with a diameter approximately equal to the outer diameter of the rotor connecting flange 82.

[0072] The non-drive end of extension 110 also supports a ring gear 112 engaged by one or more drive motors 114. Here, the ring gear 112 is shown bolted to extension 110 at bolt ring 111. The ring gear 112 and drive motor 114 provide a means by which the rotational orientation of generator rotor assembly 70 can be controlled during maintenance. For example, a maintenance engineer may need to approach a part of the generator, which would require the generator to be rotated to a certain position. The ring gear 112 and drive motor 114 also provide a means of causing rotation of the gearbox and main shaft via generator rotor assembly 70. Therefore, the axial dimension of extension 110 can be considered to be determined at least in part based on the desired position of ring gear 112. In the illustrated embodiment, extension 110 also defines a plurality of airflow holes 115. The airflow holes 115 can take any form in principle, but as shown here, there are a plurality of holes 115 distributed circumferentially around extension 110 and allowing air to flow radially outward. The airflow holes 115 can be configured to be fully open, or they can be provided with perforated covers such as grilles to ensure that debris or loose parts cannot pass through the holes 115. In addition to the airflow holes 115 defined in the extension 110, the rotor support frame 72 is also provided with a second set of airflow holes 116 (in...). Figure 8 and Figure 9 (Best visible in the middle), compared to the first set of airflow holes 115, the second set of airflow holes 116 is located radially inward. The second set of airflow holes 116 are circumferentially distributed around the transition section 90 and are spaced at equal angles in this embodiment. More specifically, each hole 116 is located at a bend defined in the transition section 90 where it sharply bends into the rotor connecting flange 82. Each hole 116 also has an associated guide channel 117 that extends axially a short distance from the corresponding hole 116 along the transition section 90. The guide channel 117 is formed as a recess or notch in the surface of the transition section 90. The number of second airflow holes 116 is not critical, but in the illustrated embodiment, each footing area 96 has two holes 116. It should be noted that the second set of airflow holes 116 is located radially outward compared to the inlet holes 100. The two sets of holes 100, 116 provide airflow benefits. However, the arrangement of two sets of holes 100, 116 at spaced radial positions promotes a more uniform airflow through the rotor support frame.

[0073] The extension 110 also supports a brake disc 118, which is fixed to a bolt ring 111 and thus positioned radially outward relative to the ring gear 112. The brake disc 118 is actuated by a set of brake actuators 119 mounted on the generator maintenance cabinet 81 and... Figure 10 It is best seen in the middle.

[0074] Based on the above discussion, it should be understood that the construction of various aspects of the generator rotor assembly in the illustrated embodiment enhances the maintainability of the various components of the generator, particularly the generator rotor assembly. For example, the internal volume of the rotor support frame 72 allows maintenance engineers access to the generator interior. This is useful for at least one of the following purposes. First, it allows 360-degree access to the tie rod system 86, the associated tension nut 89, and the balance adjustment block 87, enabling engineers to make appropriate adjustments to these components around the entire circumference of the rotor support frame 72 from a single location inside the generator. This provides a significant advantage because adjustments can be made quickly without any disassembly of machinery. Furthermore, engineers inside the generator can also have 360-degree access to the circular array 106 of bolts connecting the gearbox connecting flange 80 to the transition section 90, and also to the circular array 84 of bolts connecting the rotor support frame 72 to the gearbox output shaft, allowing for rapid inspection of these bolted connections, a significant advantage during maintenance inspections. Moreover, as mentioned above, this allows the inner hub component 102 to be removed, thereby enabling access to the gearbox shaft 77, allowing for the removal and replacement of the bearing housing. Furthermore, the significant internal space of the generator allows engineers 360-degree access to the bolted connection between the ring gear 112 and the extension 110; and similarly, access to the drive motor 114 that engages with the ring gear 112. In addition to the various components already mentioned and shown in the accompanying drawings, it should be understood that the general construction of the access hole 100 and the rotor support frame 72 facilitates access to other internal generator components, such as: a radial rotor locking system configured to lock the rotor against radial movement, for example, during maintenance; an axial rotor locking system configured to lock the rotor against axial movement; a stray current protection system; a rotary encoder which may be mounted on the gearbox output shaft; other sensor systems, such as accelerometers and temperature sensors, which may be located on the gearbox output shaft and in other locations; a brake disc assembly configured to apply braking force to the rotor during maintenance; and a pitch tube sealing assembly configured to provide a proper seal to the pitch tube assembly that passes through the powertrain assembly at its center to provide hydraulic and / or electrical power to the hydraulic pitch system located in the rotor hub.

[0075] As a whole, the rotor support frame 72 is constructed to provide a relatively open volume within it, the size and shape of which advantageously allow access for a range of maintenance activities. Therefore, this volume can be considered to define a maintenance compartment within the generator, the size and shape of which are designed to accommodate maintenance personnel. This contrasts with known methods, where access to various components is achieved only from the outside of the generator, or access from the inside of the generator is limited due to the relative positioning of internal components.

[0076] Advantageously, the open volume inside the generator rotor assembly 70 can be enclosed to provide a more protected environment, while still allowing maintenance personnel access when needed. Figure 11a and Figure 11b As shown, a closure 120, such as a door or hatch, may be provided at the rear of the generator maintenance cabinet 81. The closure 120 may be a single door panel that covers an opening 121 in the generator cabinet 81 leading to an internal chamber housing the generator rotor assembly 70. Alternatively, the closure 120 may include multiple panels. As shown, the closure 120 includes two door panels 122, 124. Those door panels 122, 124 can be mounted in any suitable manner to allow opening. For example, door panels 122, 124 may be mounted using a fastening system that allows one or both door panels to be raised away from the cabinet opening when access to the generator interior is required. Alternatively, one or both door panels 122, 124 may be hinged so that they remain attached to the generator maintenance cabinet 81, but can be moved to allow access if needed. Figure 11b One of the door panels 124 with a hinged fixing device is shown, and it should be understood that the other door panel 122 may also have such a fixing.

[0077] Advantageously, the enclosure 120 surrounds the internal volume of the generator, which means that the internal environment is separated from the general interior where the engine compartment is installed.

[0078] The enclosure 120 provides a further benefit because it offers a single access point to the generator's internal volume for maintenance purposes. This means the enclosure can be implemented with a single security mechanism to allow controlled access for maintenance. The security mechanism could be a keypad, fingerprint scanner, or other access control technology. Preferably, access through the enclosure is only permitted once the security mechanism detects that one or more other security measures or interlocks have been resolved, such as the rotor being locked to a standstill and appropriate electrical systems being deactivated, eliminating any electrical risks associated with maintenance personnel entering the generator. Since the generator's internal volume is provided as a maintenance room with sufficient space, this area can be designed as a dedicated workspace for accessing multiple structures and systems associated with the generator, as described above. For example, floor coverings can be installed in the maintenance room to capture fallen objects, thus avoiding the risk of loose parts inside the generator. Furthermore, the enclosed environment of the maintenance room, due to the enclosure 120, means that areas accessible from the maintenance room can be kept as clean as possible, which is easier to achieve on a small scale without requiring extensive cleaning of the entire engine room.

[0079] Many modifications can be made to the specific examples described above without departing from the scope of the invention as defined in the appended claims. Features of one embodiment can also be used in other embodiments, as an addition to or a replacement for that embodiment.

Claims

1. A wind turbine nacelle, the wind turbine nacelle including an outer casing defining an internal volume, the internal volume housing a power system assembly, the power system assembly comprising: Gearbox (22), which includes an input shaft (33) and an output shaft (31) aligned on a common axis of rotation (R). A generator (24) connected to the output shaft of the gearbox, wherein the generator includes a generator cabinet (81) that surrounds a stator (38) in a radially outward position and a rotor (70) in a radially inward position within an internal chamber (97), the rotor being rotatable about the common axis of rotation, wherein the rotor includes: A cylindrical field structure (74) is connected to a rotor support frame (72). A gearbox connecting flange (80) is connected to the gearbox output shaft via a first fixed array (84); The generator cabinet (81) is provided with an opening (121) that allows maintenance personnel to fully enter the internal chamber (97), and the internal chamber is configured to allow maintenance personnel to approach the first fixed array (84) that connects the gearbox output shaft (31) to the gearbox connecting flange (80) from a position that is fully located within the internal chamber (97).

2. The wind turbine nacelle according to claim 1, wherein, The rotor also includes a second fixed array (106) that connects the gearbox connecting flange (80) to the rotor support frame (72), and wherein the internal cavity (97) is configured to allow maintenance personnel to access the second fixed array (106) from the internal cavity.

3. The wind turbine nacelle according to claim 2, wherein, The first fixed array (84) has an associated first diameter (D1), and the second fixed array (106) has an associated pitch circle diameter (D3), and the first diameter (D1) of the first fixed array (84) is smaller than the pitch circle diameter (D3) of the second fixed array (106).

4. The wind turbine nacelle according to any one of claims 1 to 3, wherein, The rotor support frame (72) is connected to the cylindrical field structure (74) at the rotor connecting flange (82) by a tie rod system (86), the tie rod system including a plurality of tie rod tensioners (88) configured to tension the tie rod system, and wherein the internal chamber (97) is configured to allow maintenance personnel to access the tie rod tensioners from the internal chamber.

5. The wind turbine nacelle according to claim 4, wherein, The tie rod system (86) includes a plurality of balancing mass blocks (87) configured to provide rotational balance to the cylindrical field structure (74), and wherein the internal chamber (97) is configured to allow maintenance personnel to access the balancing mass blocks (87) from within the internal chamber.

6. The wind turbine nacelle according to any one of claims 1 to 3, wherein, The rotor (70) also includes a drive ring gear (112), and the internal chamber (97) is configured to allow maintenance personnel to access the drive ring gear (112) from within the internal chamber.

7. The wind turbine nacelle according to any one of claims 1 to 3, wherein, The cylindrical field structure (74) defines a rotor inner diameter greater than 2m.

8. The wind turbine nacelle according to any one of claims 1 to 3, wherein, The gearbox is a planetary gearbox with at least two stages.

9. The wind turbine nacelle according to claim 4, wherein, The gearbox connecting flange (80) defines a first diameter (D1), and the tie rod system (86) defines a second diameter (D2), wherein the first diameter (D1) is smaller than the second diameter (D2).

10. The wind turbine nacelle according to claim 9, wherein, The first diameter (D1) is less than 0.7m, and the second diameter (D2) is greater than 2m.

11. The wind turbine nacelle according to claim 4, wherein, The rotor connecting flange (82) of the rotor support frame (72) is spaced apart from the gearbox connecting flange (80) along the axis of rotation by a distance of at least 25% of the maximum outer diameter of the rotor support frame (72).

12. The wind turbine nacelle according to claim 11, wherein, The rotor connecting flange (82) of the rotor support frame (72) is spaced from the gearbox connecting flange (80) by a distance of less than 0.7m along the axis of rotation.

13. The wind turbine nacelle according to claim 4, wherein, The rotor connecting flange (82) of the rotor support frame (72) is spaced apart from the gearbox connecting flange (80) along the rotation axis (R) by a distance between 20% and 60% of the inner diameter of the rotor connecting flange.

14. The wind turbine nacelle according to claim 4, wherein, The rotor connecting flange (82) and the gearbox connecting flange (80) extend in mutually parallel planes.

15. The wind turbine nacelle according to claim 4, wherein, The rotor support frame (72) also includes a transition section (90) extending between the rotor connecting flange (82) and the gearbox connecting flange (80).

16. The wind turbine nacelle according to claim 15, wherein, The transition section (90) includes a generally truncated conical portion (92) that defines a cone angle (B) of less than 30 degrees.

17. The wind turbine nacelle according to claim 15, wherein, The rotor support frame (72) includes multiple access holes (100).

18. The wind turbine nacelle according to claim 17, wherein, The access hole (100) defines a minimum 100cm. 2 The opening.

19. The wind turbine nacelle according to claim 17 or 18, wherein, The inlet hole (100) is defined in the axially facing end surface portion (94) of the transition section (90).

20. The wind turbine nacelle according to claim 17 or 18, wherein, The access port (100) provides access through which to at least one of the following generator features: i) stray current protection system, ii) one or more rotation sensor components associated with the gearbox output shaft, iii) accelerometer system, iv) temperature sensor, and v) pitch tube seal.

21. The wind turbine nacelle according to any one of claims 1 to 3, the wind turbine nacelle further comprising a closure (120) covering the opening (121) in the generator cabinet (81), the closure being openable by maintenance personnel to fully access the internal chamber (97) through the opening (121).

22. The wind turbine nacelle according to claim 4, wherein, The rotor connecting flange (82) of the rotor support frame (72) is spaced apart from the gearbox connecting flange (80) along the rotation axis (R) by a distance between 20% and 40% of the inner diameter of the rotor connecting flange.

23. The wind turbine nacelle according to claim 17, wherein, The access hole (100) defines a minimum 200cm. 2 The opening.

24. A wind turbine comprising a tower and a wind turbine nacelle according to any one of the preceding claims, the wind turbine nacelle being supported on top of the tower.

25. A method for maintaining the power system of a wind turbine in the nacelle of a wind turbine, wherein, The power system includes a gearbox (22) and a generator (24), the gearbox (22) including an input shaft (33) and an output shaft (31) aligned on a common axis of rotation (R), the generator (24) being connected to the output shaft of the gearbox, wherein the generator includes a generator cabinet (81) defining an internal chamber (97) that allows maintenance personnel to enter the interior of the generator cabinet, the generator cabinet (81) surrounding a stator (38) in a radially outward position and a rotor (70) in a radially inward position, the rotor being rotatable about the common axis of rotation, wherein the rotor includes a cylindrical field structure (74) coupled to a rotor support frame (72) and a gearbox connecting flange (80) coupled to the gearbox output shaft via a first fixed array (84). The method includes: gaining access to the internal chamber (97) of the generator (24) through an opening (121) defined by the generator cabinet (81); and performing maintenance operations from a position completely located within the internal chamber (97).

26. The method of claim 25, wherein, The maintenance operation includes maintenance by maintenance personnel from a position fully located within the internal cavity of at least one of the following: i) a second fixed array (106) connecting the gearbox connecting flange (80) to the rotor support frame (72); ii) a tie rod system (86) connecting the rotor support frame (72) to the cylindrical field structure (74); iii) a plurality of balancing mass blocks (87) configured to provide rotational balance to the cylindrical field structure (74); iv) Drive the ring gear (112).

27. The method according to claim 25 or 26, wherein, The step of gaining access to the internal chamber of the generator (24) includes releasing the closure (120) covering the opening (121) of the generator cabinet (81), thereby exposing the opening (121) for access to the internal chamber (97).

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