Stator for a generator of a wind turbine

Abstract

A stator (100) for a generator (10), in particular for a wind turbine (1), is described. The stator (100) comprises: an inner frame structure (110) having an annular shape formed around a rotation axis (Y) corresponding to the axial direction of the generator (10); and an outer frame structure (121, 122) formed around the rotation axis (Y) and surrounding the inner frame structure (110), the outer frame structure (121, 122) being radially spaced from the inner frame structure (110); and a plurality of spokes (150) distributed around the rotation axis (Y) and connecting the inner frame structure (110) and the outer frame structure (121, 122).

Description

Technical Field

[0001] The present invention relates to the technical field of generators, in particular generators for wind turbines. In particular, the present invention relates to a stator assembly for a generator having a lightened structure. Furthermore, the present invention relates to a generator and a wind turbine comprising such a stator assembly. Background Art

[0002] A wind turbine is manufactured, comprising a generator having a stator assembly having an inner frame structure and an outer frame structure, the outer frame structure surrounding the inner frame structure and which supports the conductive coils of the generator. Examples of such stator assemblies are disclosed in EP 3226383 and EP 3252928.

[0003] Such assemblies can be very heavy in construction, complex and expensive to build, and are often at the limits of manufacturing and transport for large turbines.

[0004] Therefore, it is desirable to replace this structure with another structure that is lighter and easier to manufacture. Summary of the invention

[0005] This object is achieved by the subject matter according to the independent claim.The dependent claims describe advantageous embodiments of the invention.

[0006] According to the present invention, a stator assembly for a generator, in particular a generator for a wind turbine, is provided. The stator comprises an inner frame structure and an outer frame structure, the inner frame structure having an annular shape formed around a rotation axis of the generator; and the outer frame structure is formed around a central axis and surrounds the inner frame structure, the outer frame structure being radially spaced from the inner frame structure. The stator comprises a plurality of spokes distributed around the central axis and connecting the inner frame structure and the outer frame structure.

[0007] The described spoked stator assembly allows for a lighter structure relative to the prior art. The spokes extend radially between the inner and outer frame structures to provide the stator with the desired structural mechanical properties at a lighter weight relative to the prior art.

[0008] According to an embodiment of the invention, the outer frame structure comprises two outer rings coaxial with the axis of rotation. The inner frame structure may comprise an inner ring coaxial with the axis of rotation Y. In such an embodiment, each spoke provides a structural connection between the inner ring and the two outer rings. The use of rings also allows minimizing the weight of the inner and outer frame structures.

[0009] According to an embodiment of the invention, each spoke has a diverging shape extending from a vertex fixed to the inner ring and diverging toward the two outer rings. This provides a simple, light and efficient geometry for connecting the inner ring and the outer ring.

[0010] According to an embodiment of the invention, the stator further comprises an intermediate frame structure attached to at least a portion of the plurality of spokes, the intermediate frame structure being radially included between the inner frame structure and the outer frame structure. The intermediate frame structure may comprise an annular flange at least partially surrounding the inner frame structure around the axis of rotation. The intermediate frame structure provides a support for attaching stator components, such as: at least one rotation device attached to the stator intermediate frame structure and comprising an actuator and a gear driveable by the actuator, the gear engaging with the toothed profile to rotate the rotor; and / or at least one brake caliper attached to the intermediate frame structure, the brake caliper acting on the annular device for slowing down the rotation of the rotor around the axis of rotation; and / or a rotor locking system attached to the intermediate frame structure, the rotor locking system comprising at least one piston that can be axially moved along the axis of rotation for engaging at least one hole provided on the annular device so as to block and lock the rotor in a desired angular position around the axis of rotation.

[0011] The aspects defined above and further aspects of the invention are apparent from the examples of embodiment to be described hereinafter and will be explained with reference to the examples of embodiment.The invention will be described in more detail hereinafter with reference to examples of embodiment but to which the invention is not limited. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A schematic diagram of a wind turbine including a generator is shown.

[0013] Figure 2 Shows Figure 1 A partial isometric detail view of a generator including a stator according to an embodiment of the present invention.

[0014] Figure 3 Shows Figure 2 Another partial axonometric view of the generator.

[0015] Figure 4 Shows Figure 2 Another partial axonometric view of the generator.

[0016] Figure 5 Shows Figure 2 Another partial axonometric view of the generator. DETAILED DESCRIPTION

[0017] The illustrations in the figures are schematic. Note that in different figures, similar or identical elements or features have the same reference numerals. In order to avoid unnecessary repetition, elements or features that have been explained with respect to the previously described embodiments are no longer explained in the later position of the description.

[0018] Figure 1A wind turbine 1 according to the invention is shown. The wind turbine 1 comprises a tower 2 mounted on a foundation not shown. A nacelle 3 is arranged on top of the tower 2. The wind turbine 1 further comprises a wind rotor 5 (in Figure 1 In the embodiment of the invention, the wind rotor comprises three blades 4, of which only two blades 4 are visible). The wind rotor 5 is rotatable about an axis of rotation Y. The blades 4 extend substantially radially relative to the axis of rotation Y and along the respective longitudinal axis X. Generally, when no particular different provisions are made, the terms axial, radial and circumferential in the following text are made with reference to the axis of rotation Y. The wind turbine 1 comprises a generator 10, which comprises a stator 100 and a rotor 200. The rotor 200 is rotatable relative to the stator 100 about the axis of rotation Y. The wind rotor 5 is driven directly (e.g. directly) or via a rotatable main shaft 9 and / or via a gearbox ( Figure 1 The main shaft 9 and the rotor 5 are rotationally coupled to the main shaft 9 and the rotor 5. The main shaft 9 extends along the rotation axis Y. In order to provide an AC power signal matching the utility grid, the power output of the generator 10 is electrically connected to a power converter 18 arranged in the nacelle 3. However, such a converter can also be placed outside the nacelle, for example inside or even outside the tower 2.

[0019] Figures 2 to 5 A partial representation of the generator 10 is shown in more detail.

[0020] The stator 100 comprises an inner frame structure 110 having an annular shape formed around the rotation axis Y. According to the exemplary embodiment described here, the inner frame structure is realized by an inner ring 110 coaxial with the rotation axis Y. According to other embodiments (not shown in the drawings), the inner frame structure is realized by other annular structures.

[0021] The stator 100 comprises an outer frame structure formed around a central axis Y and surrounding an inner frame structure 110, the outer frame structure being radially spaced from the inner frame structure 110. According to the exemplary embodiment described here, the outer frame structure is realized by two outer rings 121, 122, which are coaxial with the axis of rotation Y and have the same diameter, which is greater than the diameter of the inner ring 110. The two outer rings 121, 122 are spaced apart from each other along the longitudinal axis Y. The stator 100 further comprises a plurality of stator segments 160 (only one stator segment is shown in the figures), each stator segment comprising at least one conductor coil 161, in which magnetic induction occurs during normal operation of the generator 10. According to the exemplary embodiment described here, each of the stator segments 160 is fixed to two of the two outer rings 121, 122, for example by a plurality of bolts.

[0022] The stator 100 further comprises a plurality of spokes 150 which are distributed around the longitudinal axis Y and connect the inner frame structure 110 and the outer frame structure 121, 122. The plurality of spokes 150 may be regularly distributed around the longitudinal axis Y. According to the exemplary embodiment described herein, each of the plurality of spokes 150 is fixed to the inner ring 110 and the outer ring 121, 122, for example, by a corresponding plurality of bolts or by welding. Each spoke 150 has a flat shape, substantially along a corresponding radial plane including the longitudinal axis Y. Each spoke 150 has a divergent shape extending from a first vertex 151 and radially diverging outwardly until a second vertex 152 and a third vertex 153. At the first vertex 151, each spoke 150 comprises two curved inner fins 154 which are coaxial with the longitudinal axis Y. The two inner fins 154 are fixed to the inner ring 110 by a corresponding plurality of bolts or by welding. At each of the second vertex 152 and the third vertex 153, each spoke 150 includes a curved outer fin 155, which is coaxial with the longitudinal axis Y. The two outer fins 155 of each spoke 150 are fixed to the two outer rings 121, 122, respectively. Each spoke 150 may include one or more holes 157 (in the exemplary embodiment of the drawings, two holes 157 are provided for each spoke 150) for reducing the weight of each spoke 150 and thus reducing the weight of the stator 100. According to another exemplary embodiment of the present invention (not shown), each spoke may have an open configuration, according to a "V"-shaped extension between the first vertex 151 and the second vertex 152 and the third vertex 153. According to another exemplary embodiment of the present invention (not shown), each spoke may have a simple closed triangular configuration with three vertices 151, 152, 153. According to another exemplary embodiment of the present invention (not shown), each spoke may have a simpler linear and purely radial configuration connecting the inner frame structure 121 and the outer frame structure 122. In the latter embodiment, the outer frame structure may still comprise two rings 121 , 122 connected to one another by other elements parallel to the longitudinal axis Y.

[0023] Figures 2 to 5 Also shown is an annular device 210 (not further shown and described) fixed to the rotor 200. The annular device 210 is an annular planar flange extending 360° around the longitudinal axis Y between the inner frame structure 110 and the outer frame structures 121, 122. The annular planar flange 210 is therefore substantially located in a plane orthogonal to the axis of rotation Y. The annular device 210 comprises a toothed profile 220 arranged on a circular edge facing the outer frame structures 121, 122. The annular device 210 is used to rotate the rotor 200 in a controlled manner, for example for installation and maintenance procedures up to an angularly desired position around the axis of rotation Y, and for slowing down the rotational movement of the rotor 200 in a controlled manner.

[0024] The stator 100 also includes an intermediate frame structure 180 attached to a portion of the plurality of spokes 150. According to another exemplary embodiment (not shown), the intermediate frame structure 180 is attached to all spokes 150. The intermediate frame structure 180 is radially contained between the inner frame structure 110 and the outer frame structures 121, 122. According to the exemplary embodiment described herein, the intermediate frame structure 180 is a planar annular flange that partially surrounds the inner frame structure 110 around the rotation axis Y, i.e., the planar annular flange extends circumferentially less than 360 degrees around the longitudinal axis Y. The annular planar flange 180 is substantially located on a plane orthogonal to the rotation axis Y. The stator 100 also includes one or more rotating devices 185 ( Figure 4 Five rotating devices 185 are shown in the figure). Each rotating device 185 includes an actuator 186 and a gear 187. Each gear 187 can be driven by the actuator 186 and engages with the toothed profile 220 for rotating the rotor 200 in a controlled manner. The rotating device 185 can move the rotor 200 in a controlled manner so that it enters a predetermined angular position. At the predetermined angular position, the movement of the rotor assembly will be stopped by stopping the operation of the rotating device. This can be achieved simply by stopping the operation of the actuator. In addition, a braking system and / or a mechanical blocking system can be used to maintain the proper angular position of the rotor assembly. The braking system is provided by one or more brake calipers 189 attached to the intermediate frame structure 180. Each brake caliper acts on the annular device 210 to slow down the rotation of the rotor 200 around the rotation axis Y. After the rotor is stopped, the brake caliper can also be used to prevent the rotor 200 from moving when it is enabled.

[0025] The stator 100 further comprises a rotor locking system 190 attached to the intermediate frame structure 180, the rotor locking system 190 comprising at least one piston 191 axially displaceable along the rotation axis Y for engaging at least one hole 222 provided on the annular device 210 in order to block and lock the rotor 200 in a desired angular position about the rotation axis Y. According to the exemplary embodiment described here, the annular device 210 comprises a plurality of holes 222 regularly distributed about the rotation axis Y. For example, N holes 222 may be provided on the annular device 210 for blocking the rotor 200 at N corresponding positions, each annular position being 360° / N from the adjacent annular position.

Claims

1. A stator (100) for a generator (10), the stator (100) comprising: an inner frame structure having an annular shape formed around a rotation axis (Y) of the generator (10), wherein the inner frame structure comprises an inner ring (110) coaxial with the rotation axis (Y); and an outer frame structure formed around the rotation axis (Y) and surrounding the inner frame structure, the outer frame structure being radially spaced from the inner frame structure, wherein the outer frame structure comprises two outer rings (121, 122) spaced from each other along the rotation axis (Y), The stator (100) comprises a plurality of spokes (150), wherein the plurality of spokes (150) are distributed around the rotation axis (Y) and connect the inner frame structure and the outer frame structure. wherein the plurality of spokes (150) are fixed to the inner ring (110) and the outer ring (121, 122), and Each spoke (150) has a divergent shape extending from a vertex (151) fixed to an inner ring (110) and diverging toward two outer rings (121, 122).

2. The stator (100) according to claim 1, further comprising: A plurality of stator segments (160), each stator segment comprising at least one conductor coil (161), in which magnetic induction occurs during normal operation of the generator (10), wherein: The stator segments (160) are mounted on the outer frame structure.

3. The stator (100) according to claim 1, wherein: The generator (10) is a generator for a wind turbine (1).

4. A generator (10), comprising: The stator (100) according to any one of claims 1 to 3, A rotor (200) comprising an annular device (210) comprising a toothed profile (220); The stator (100) further comprises: an intermediate frame structure (180) attached to at least a portion of the plurality of spokes (150), the intermediate frame structure (180) being radially included between the inner frame structure and the outer frame structure, At least one rotating device (185) is attached to the stator intermediate frame structure (180) and comprises an actuator (186) and a gear (187) drivable by the actuator (186), the gear (187) engaging with the toothed profile (220) to rotate the rotor (200).

5. The generator (10) according to claim 4, wherein: The intermediate frame structure (180) comprises an annular flange at least partially surrounding the inner frame structure around the rotation axis (Y).

6. The generator (10) according to claim 4 or 5, further comprising At least one brake caliper (189) is attached to the intermediate frame structure (180), the brake caliper acting on the annular device (210) for slowing down the rotation of the rotor around the rotation axis (Y).

7. The generator (10) according to claim 4 or 5, further comprising A rotor locking system (190) is attached to the intermediate frame structure (180) and comprises at least one piston (191) which is axially movable along the rotation axis (Y) for engaging at least one hole (222) provided on the annular device (210) so as to block the rotor (200) at a desired angular position about the rotation axis (Y).

8. A wind turbine (1) comprising a generator (10) according to any one of claims 4 to 7.

Images