Generator for wind turbine, generator stator and wind turbine

Abstract

A generator (7) for a wind turbine comprising an inner stator (10) and a rotatably mounted outer rotor (11), wherein at least one brake support plate (23) of the generator (7) has at least one braking member (21) arranged thereon, the at least one braking member (21) adapted to interact with at least one brake disc (22) mounted on the rotor (11) to brake and / or lock the rotation of the rotor (11), and wherein the at least one brake support plate (23) is one of several laminated stator plates (14) making up the iron core (13) of the stator (10).

Description

[Technical Field]

[0001] The present invention relates to a generator for a wind turbine comprising an inner stator and a rotatably mounted outer rotor, wherein at least one brake support plate of the generator has at least one braking member arranged thereon, the at least one braking member being adapted to interact with at least one brake disc mounted on the rotor to brake and / or lock the rotor from rotating. The present invention further relates to an inner stator for a generator. In addition, the present invention relates to a wind turbine.

[0002] In particular for maintenance purposes, it may be necessary to brake or lock the rotation of the generator of a wind turbine. The rotation of the respective components of the generator or the wind turbine itself may pose a danger to service personnel working in the vicinity of these components. Therefore, the generator of a wind turbine needs to implement a braking system to slow down and / or lock the rotation or movement of these components.

[0003] EP 2 896 824 A1 discloses a braking system for a wind turbine generator in which a ring-shaped component is connected to a flange of a stator assembly and friction members are mounted on the component for frictional engagement with a brake disc connected to an outer rotor.

[0004] The object of the present invention is to realize an improved concept for a braking system of a generator for a wind turbine, in particular with regard to the weight of the generator and the manufacturing process.

[0005] To solve this problem, the generator described at the beginning is characterized in that at least one brake support plate is one of several laminated stator plates that make up the stator core.

[0006] The present invention is based on the idea that instead of having separate components for mounting the braking members, the stator plates are used synergistically to achieve the respective functions. Therefore, the generator according to the present invention does not require the ring-shaped component described in EP 2 896 824 A. Therefore, the generator according to the present invention can be manufactured more easily and its overall weight is reduced.

[0007] The generator comprises an inner stator and an outer rotor, so that the rotor is a so-called outer rotor. At least a portion of the rotor extends along a portion of the generator located radially outside the stator. The rotor is rotatably mounted on a rotation axis. The stator can be cylindrical in shape, and the rotor can be hollow cylindrical in shape. The central axis of each cylinder is preferably the same and is also the same as the rotation axis of the rotor. The rotation axis therefore extends along the longitudinal or axial direction of the stator and / or rotor. The direction pointing perpendicularly away from the rotation axis is defined as the radial direction. The direction pointing perpendicularly away from the radial direction, towards the direction in which a point rotates around the rotation axis, is defined as the circumferential direction.

[0008] The generator can be a permanent magnet generator with multiple permanent magnets on a rotor and multiple stator windings on a stator, forming coils, forming an electrical circuit. Rotation of the rotor causes a change in the magnetic field in the wires of the stator windings, which in turn causes an electric current. If the generator is installed in a wind turbine, wind-driven rotation of the rotor causes rotor rotation and therefore current in the electrical circuit, which is used to generate energy or electricity. The output power of the generator can be in the multi-megawatt range, specifically between 1 and 40 megawatts.

[0009] The stator of the generator according to the invention comprises several laminated stator plates constituting the stator core, which may comprise a plurality of teeth projecting radially outward, with two adjacent teeth defining slots laterally, and within which are located portions of the stator windings extending along the longitudinal direction of the stator.

[0010] The brake disc may be a ring-shaped component, which may be attached to the rotor, in particular at its axial front face, and may be made of metal.

[0011] In a preferred embodiment, the at least one brake support plate is at least one axial end plate of the core. The brake support plate implements the axial front or end face of the stator. Preferably, at least one braking element is attached to each axial end face. Alternatively, the at least one brake support plate is at least one axial center plate of the core. In this embodiment, the brake support plate is axially located between two further stator plates. In this embodiment, the braking elements can be arranged on the circumferential surface of the brake support plate.

[0012] The generator according to the invention may be a direct drive generator, meaning that in this embodiment the wind turbine or generator is gearless and the gearbox is replaced by a generator, preferably a multi-pole generator constituting a synchronous generator.

[0013] Assuming the generator is a direct-drive generator, one of the at least one brake support plates can be a non-drive end of a stator plate. In this embodiment, the stator has a drive end and a non-drive end that define opposing axial end faces or axial front faces of the stator and extend along a radial direction. The drive end can be tapered in the radial direction. The drive end faces the main shaft that connects the rotor of the generator to the rotor of the wind turbine. However, it is also possible in principle for one of the at least one brake support plates to be a drive end stator plate.

[0014] At least one braking member may be attached to an outer radial end of at least one brake support plate. The brake support plate may have a cylindrical geometry with a circumferential surface and two flat and circular front faces, one of which may be the front face of the stator. The outer radial end may be defined as a portion of the brake support plate comprising the circumferential surface and a radially outer portion of the front face. The radially outer portion may be defined such that the radial distance between the rotation axis and this portion is at least 30%, in particular at least 50%, preferably at least 80% of the total radius of the circular brake support plate.

[0015] In a preferred embodiment of the generator according to the present invention, at least one of the at least one braking member may extend radially outward relative to the rotor's rotation axis, and at least one of the at least one brake disc may extend radially inward relative to the rotation axis, with at least a portion of the at least one braking member and at least a portion of the at least one brake disc being arranged adjacent to each other relative to the rotation axis and / or radially. Axial and / or radial movement of the at least one braking member or at least a portion of the at least one braking member may create a mechanical interaction between the respective braking member and the brake disc to brake and / or lock the rotor. In this embodiment, it is also possible for portions of the braking member to be located on two opposite axial sides of the brake disc.

[0016] Preferably, several braking elements are provided. In this embodiment, the mechanical load caused by braking and / or locking of the brake disc is not transmitted to the brake support plate via just one location, but is instead distributed across the support plate over several braking elements. This reduces the yielding effect of the brake support plate caused by the respective mechanical stresses, improving mechanical stability.

[0017] The braking elements can be located in the upper part of the generator, specifically in the upper quarter. The upper part typically refers to the height of the generator perpendicular to the axis of rotation. Alternatively, the braking elements can be evenly distributed around the circumference of the stator.

[0018] At least one braking member may comprise or be coupled to an application device, in particular an electromechanical, hydraulic or pneumatic device, in which the braking member or at least a part of the braking member is movable by the application device to interact with the brake disc to achieve braking and / or locking of the rotor rotation.

[0019] In particular, at least one of the at least one braking member may be or may comprise at least one brake caliper and / or at least one brake shoe configured to frictionally interact with at least a portion of the at least one brake disc to brake and / or lock the rotor. The caliper may comprise two brake shoes arranged on either side of the brake disc in the axial direction. Braking or locking is caused by moving the brake shoes in opposite directions, so that the brake pads come into contact, particularly frictional contact, with the brake disc on opposite axial surfaces, particularly in the axial direction. The at least one brake shoe may comprise a backing plate, particularly made of steel, with a friction material bonded to its surface facing the brake disc.

[0020] At least one of the at least one braking member may be or may include at least one locking pin and / or at least one locking bolt and / or at least one locking shim configured to be moved into a position that engages with at least one recess and / or at least one hole in the at least one brake disc to lock rotation of the rotor. Once rotation of the rotor is stopped, particularly by the caliper, and the position of the recess or hole is aligned with the position of the locking pin or locking bolt or locking shim, the pin or bolt or shim can be moved axially into the recess or hole. When the locking pin or locking bolt or locking shim engages with the respective recess or hole, rotation of the brake disc, and therefore the rotor, is prevented.

[0021] At least one of the at least one braking member may be attached to the at least one brake support plate by at least one foot element, which provides an axial gap between the at least one braking member and the axial front surface of the core. The foot element may be made of metal. In this embodiment, the foot element extends axially and is located between the brake support plate and the braking member. A stator end winding of the stator may be disposed in the axial gap.

[0022] At least one of the at least one foot elements may comprise a base portion, which is attached to the at least one brake support plate, in particular by a welding and / or bolting and / or screwing connection. The cross section of the foot element or the base portion may widen toward the brake support plate so that the side of the foot element attached to the brake support plate provides a large contact area between the brake support plate and the foot element. In particular, the base portion may be attached to a mounting plate attached to the brake support plate. The mounting plate and the base portion may also be made in one piece.

[0023] The stator may have at least one opening on its axial front surface of the iron core or on the axial front surface of one of the iron cores, and cooling air and / or cooling liquid may be guided into the stator through the at least one opening. The wind turbine may have a cooling system for guiding cooling means, such as cooling air and / or cooling liquid, into the stator, particularly to cool the stator windings. The cooling system may be an open system or a closed system realizing a cooling circuit. Since the stator plate is used as a brake support plate instead of a separate component, the cooling channels of the cooling system may be directly connected to the stator without having to pass through the area of ​​a separate component.

[0024] At least one functional component can be mounted on the at least one brake support plate, at least one of which is part of the air gap fixing system or lightning protection system of the generator. In this embodiment, the stator plate realizing the brake support plate further acts synergistically as a holding means for further components of the generator, i.e., the functional component.

[0025] The present invention further relates to an inner stator for a generator according to the above description, wherein at least one brake member is arranged on at least one brake support plate of the stator, the at least one brake member being adapted to interact with at least one brake disc mounted on a rotatably mounted outer rotor of the generator in order to brake and / or lock the rotation of the rotor, the at least one brake support plate being one of several laminated stator plates constituting the stator core. All advantages and features of the generator according to the invention can be transferred to the inner stator according to the invention and vice versa.

[0026] Additionally, the present invention relates to a wind turbine comprising at least one generator according to the above description. All advantages and features of the generator according to the invention and the inner stator according to the invention can be transferred to the wind turbine according to the invention and vice versa.

[0027] Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings, which are merely sketches of principles designed for purposes of illustration only and are not intended to limit the invention. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a schematic diagram of a wind turbine according to an embodiment of the invention, comprising a generator according to an embodiment of the invention; [Figure 2]2 is a schematic view of a radial section through the generator of the wind turbine of FIG. 1 with an inner stator according to an embodiment of the present invention, the section line being indicated in FIG. 1 by II-II. [Figure 3] FIG. 2 is a schematic view of a longitudinal section through the generator of the wind turbine of FIG. 1. [Figure 4] 4 is an enlarged view of a portion of the generator of FIG. 3, designated by IV in FIG. 3; [Figure 5] FIG. 4 is a schematic perspective view of the inner stator mated with the brake disc of the generator of FIG. 3; [Figure 6] FIG. 6 is a schematic diagram of a braking member attached to the inner stator of FIG. 5. [Figure 7] 7 is a schematic view of a foot element for a braking member according to a different embodiment to the embodiment shown in FIG. 6.

[0029] FIG. 1 shows a wind turbine 1 according to an embodiment of the present invention. The wind turbine 1 comprises a tower 2 on which a nacelle 3 is arranged. A hub 4 having several, in particular three, blades 5 is provided at the front of the nacelle 3. The hub 4 is mounted so that it can rotate about a rotation axis 6. The wind-driven rotation of the hub 4 is transmitted to a generator 7 according to an embodiment of the present invention, located within the nacelle 3, by a main shaft 8 extending along the rotation axis 6. The rotation axis 6 defines the axial direction of the generator 7. The rotation axis 6 is arranged horizontally, but can also be inclined relative to the horizontal. While the total height of the wind turbine 1 is on the order of tens or hundreds of meters, the output power of the wind turbine 1 generated by the generator 7 can be in the multi-megawatt range, in particular between 1 and 40 megawatts.

[0030] The generator 7 comprises an inner stator 10 according to one embodiment of the present invention and an outer rotor 11. The stator 10 and rotor 11 are disposed within a housing 9 of the generator 7. While the stator is not rotating, the rotor 11 is connected to the main shaft 8 such that the rotation of the hub 4 is transmitted to the rotor 11. Therefore, the rotor 11 can also rotate about the rotation axis 6.

[0031] FIG. 2 shows a cross-section through a portion of the generator 7, the cut plane perpendicular to the rotation axis 6. An air gap 12, several millimeters thick, is disposed between a cylindrical stator 10 and a hollow cylindrical rotor 11. The stator 10 comprises an iron core 13 with several laminations of stator plates 14. The stator plates 14 are arranged perpendicular to the rotation axis 6, so that the laminations of the iron core 13 extend along the axis 6. The stator plates 14, and therefore the iron core 13, comprise a plurality of teeth 15 projecting in a radial direction 16 extending perpendicularly outward from the rotation axis 6. The teeth 15 are evenly spaced along a circumferential direction 17, defined as the direction perpendicularly pointing away from the radial direction 16 toward the direction in which the rotor 11 rotates about the rotation axis 6. Two adjacent teeth 15 laterally define slots within which stator windings 18 for realizing coils are disposed. The windings 18 include end windings 20 (not shown in FIG. 2) which each have a curved shape and which connect the windings 18 of several, particularly adjacent slots.

[0032] The rotor 11 includes permanent magnets 19 evenly spaced along a circumferential direction 17. The rotating permanent magnets 19 of the rotor 11 and the windings 18 of the stator 10 interact electromagnetically such that currents are induced in the windings 18 to provide the power output of the generator 7.

[0033] Reference is now made to Figures 3 and 4. Figure 3 shows a longitudinal section of the generator 7 along the axis of rotation 6. Figure 4 shows an enlarged portion of Figure 3, indicated by box IV. The housing 9 is not shown in Figures 3 and 4.

[0034] The inner stator 10 is fitted with several braking members 21. The outer rotor 11 is fitted with brake discs 22. The braking members 21 are adapted to interact with the brake discs 22 to brake and lock the rotation of the rotor 10 and, thereby, the components connected to it, such as the main shaft 8 and hub 4. Typically, when maintenance work must be performed, the rotation of the hub 4, main shaft 8, and rotor 11 must be stopped to avoid danger to the respective service personnel. To stop the rotation, in a first step, the tiling angle of each of the blades 5 is adjusted so that aerodynamic effects result in a deceleration of the rotation. Once the respective rotational frequencies fall below a certain value, in a second step, the braking members 21 are activated to slow the rotation to zero, and in a third step, the rotation of the non-rotating rotor 11 is finally locked.

[0035] The braking member 21 is arranged and mounted on a brake support plate 23 constituted by one of the stator plates 14, in this embodiment exemplarily by the axial end plate of the iron core 13 which realizes the non-drive end stator plate of the generator 7 as a direct drive generator. The brake support plate 23 therefore realizes an axial front face 24 of the iron core 13 opposite the front end of the iron core 13 facing the main shaft 8 and the hub 4.

[0036] The brake support plate 23 has the geometric shape of a flat cylinder with a circularly curved circumferential face 25 and two circular end axial front faces 26, one of which constitutes the axial front face 24 of the iron core 13. The braking members 21 are mounted on the outer radial ends of the brake support plate 23.

[0037] The stator 11 is a hollow cylinder with the rotary shaft 6 as its centerline, and a flange 27 is provided on the front surface of the rotor 11 that faces the main shaft 8. The brake disc 22, which has a circular ring shape, is attached to the flange 27 by a screw fastening means 28.

[0038] As can be seen particularly in Figures 3 and 4, the braking members 21 extend radially outward and the brake discs 22 extend radially inward such that a portion of each of the braking members 21 and a portion of the brake discs 22 are positioned adjacent to one another along the axial direction.

[0039] FIG. 5 shows a perspective view of the stator 10 and the brake disc 22. As can be seen from the figure, the generator 7 includes several functional components 43, 44 mounted on the brake support plate 23. The first functional component 43 constitutes an air gap fixing system, and the second functional component 44 constitutes a lightning protection system for the generator 7. Illustratively, the braking members 21 are located in the upper part, i.e., the upper quarter, of the generator 7. The upper part refers to the height of the generator 7 extending perpendicular to the rotation axis 6. Alternatively, the braking members 21 are evenly distributed along the circumferential direction 17 of the stator 10.

[0040] FIG. 6 shows an enlarged view of one of the braking members 21. Details regarding the braking members 21 will now be described, particularly with reference to FIGS. 4 to 6. Each of the braking members 21 comprises a brake caliper 29 having two brake pads or brake shoes 30 arranged axially and having a brake disc 22 therebetween. The brake shoes 30 are configured to frictionally interact with the brake disc 22. In particular, the brake shoes 30 are movable relative to one another so as to come into frictional contact with the brake disc 22 and cause a slowdown of their respective rotations. For this purpose, the brake shoes 30 are connected to an application device, not shown in the figures, in particular an electromechanical, hydraulic or pneumatic application device.

[0041] As can be seen from Figure 4, the braking member 21 comprises a locking pin 31 which can be moved along the radial direction 16 into a position where it engages with a hole 32 or recess in the brake disc 22 to lock the rotation of the rotor 11. Instead of a locking pin, at least one locking bolt and / or at least one locking shim of the braking member 21 may also be provided.

[0042] Regarding the locking process of the rotors 11, once the respective rotations have been aerodynamically slowed as described above, the brake calipers 29 are used to frictionally slow the rotation of the rotors 11 to zero, and the brake discs 22 are moved into a position where each of the holes 32 is aligned with one of the locking pins 31. The locking pins 31 are then moved into a position where they engage with the holes 32. For this purpose, an activation device of the locking means 21, not shown, is provided.

[0043] The braking members 21 are mounted to the brake support plate 23 by respective foot elements 33 that provide an axial gap 34 between the respective braking member 21 and the axial front face 24. The axial gaps 34 provide space for the stator end windings 20 such that the stator end windings 20 are positioned in the axial gaps 34 between the core 13 and the braking members 21, as can be seen particularly from FIG.

[0044] Each foot element 33 comprises a base part 35 which is mounted to the brake support plate 23, exemplarily by means of screwing means 36. For this purpose, the base part 35 is connected to a mounting plate 37 of the foot element 33, which constitutes a large contact area between the foot element 33 and the brake support plate 23. The cross section of the base part 35 widens towards the brake support plate 23. The base part 35 and the mounting plate 37 are exemplarily welded to one another. On the side of the base part 35 facing the brake support plate 23, a surface 45 of the foot element 33 is provided, to which the braking means 21 are mounted, e.g. by means of screwing means.

[0045] Figure 7 shows another possible embodiment of the invention with differences regarding the foot element 33. For better visibility, the braking member 21 is not shown in this figure. In this embodiment, the foot element 33 is made in one piece and no mounting plate 37 is provided. The base portion 35 comprises a widened portion 46 to increase the contact area between the foot element 33 and the brake support plate 23. The foot element 33 and the brake support plate 23 are welded to each other.

[0046] 3 and 5 , an embodiment of a cooling system 39 of the wind turbine 1 for cooling the generator 7 is described. The stator 10 comprises a number of openings 38 on the axial front face 24 of the core 13, through which a cooling means such as cooling air or a cooling liquid can be guided in and out of the stator 10. Exemplarily, the cooling system 39 is a closed air-cooling system 39 having, among other things, a fan 40 and an air-cooling unit 41 comprising, among other things, a heat exchanger and / or other cooling components for cooling the cooling air. The cooling system 39 realizes a cooling circuit having cooling channels or guiding means 42 for guiding the cooling air. The guiding means 42 can be hoses and / or ducts and / or pipes.

[0047] Although the present invention has been described in detail with reference to preferred embodiments, the invention is not limited to the disclosed examples, and those skilled in the art can derive other variations therefrom without departing from the scope of the invention.

Claims

1. A generator (7) for a wind turbine, comprising an inner stator (10) and a rotatably mounted outer rotor (11), wherein at least one brake support plate (23) of the generator (7) is provided with at least one braking member (21), the at least one braking member (21) being adapted to interact with at least one brake disc (22) mounted on the rotor (11) to brake and / or lock the rotation of the rotor (11), wherein the at least one brake support plate (23) is one of several laminated stator plates (14) constituting the iron core (13) of the stator (10).

2. The generator according to claim 1, characterized in that the at least one brake support plate (23) is at least one axial end plate of the iron core (13).

3. The generator according to claim 2, characterized in that the generator (7) is a direct drive generator, and one of the at least one brake support plate (23) is a non-drive end stator plate (14).

4. The generator according to claim 1, characterized in that the at least one braking member (21) is mounted on the outer radial end of the at least one brake support plate (23).

5. The generator according to claim 1, characterized in that at least one of the at least one braking member (21) extends radially outward with respect to the rotation axis (6) of the rotor (11), at least one of the at least one brake disc (22) extends radially inward with respect to the rotation axis (6), and at least a portion of the at least one braking member (21) and at least a portion of the at least one brake disc (22) are arranged adjacent to each other with respect to the rotation axis (6) and / or radial direction (16).

6. The generator according to claim 1, characterized in that several braking members (21) are provided, the braking members (21) are arranged on the upper part of the generator (7), particularly the upper quarter, or are evenly distributed along the circumferential direction (17) of the stator (10).

7. The generator according to claim 1, wherein at least one of the at least one braking member (21) is or comprises at least one brake caliper (29) and / or at least one brake shoe (30) configured to frictionally interact with at least a portion of the at least one brake disc (22) to brake and / or lock the rotation of the rotor (11).

8. The generator according to claim 1, wherein at least one of the at least one braking member (21) is or comprises at least one locking pin (31) and / or at least one locking bolt and / or at least one locking shim configured to move to a position that engages with at least one recess and / or at least one hole (32) of the at least one brake disc (22) in order to lock the rotation of the rotor (11).

9. The generator according to claim 1, wherein at least one of the at least one braking member (21) is attached to the at least one brake support plate (23) by at least one foot element (33), and the at least one foot element (33) provides an axial gap (34) between the at least one braking member (21) and the axial front surface (24) of the iron core (13).

10. The generator according to claim 9, characterized in that the stator end winding (20) of the stator (10) is arranged in the axial gap (34).

11. The generator according to claim 9, wherein at least one of the at least one foot element (33) comprises a base portion (35), the base portion (35) being attached to the at least one brake support plate (23) in particular by welding and / or bolting and / or screw connection (36).

12. The generator according to claim 1, wherein the stator (10) is provided with at least one opening (38) on the axial front surface (24) of the core (13) or on one axial front surface (24) of the core (13), and cooling air and / or coolant can be guided into the stator (10) through the at least one opening (38).

13. The generator according to claim 1, characterized in that at least one functional component (43, 44) is mounted on the at least one brake support plate (23), and at least one of the at least one functional component (43, 44) is part of an air gap fixing system or a lightning protection system of the generator (7).

14. An inner stator for a generator (7) according to any one of claims 1 to 13, wherein at least one brake support plate (23) of the stator (10) is provided with at least one braking member (21), the at least one braking member (21) is adapted to interact with at least one brake disc (22) mounted on a rotatably mounted outer rotor (11) of the generator (7) to brake and / or lock the rotation of the rotor (11), and the at least one brake support plate (23) is one of several laminated stator plates (14) that constitute the iron core (13) of the stator (10).

15. A wind turbine comprising at least one generator (7) according to any one of claims 1 to 13.

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