Stator segment for an electric machine and method for assembly

Abstract

The invention relates to a stator segment for an electric machine and a method for assembly. In particular, the present disclosure relates to a stator segment for an electric machine. The stator segment includes a base for mounting to the stator structure, a tooth extending between a first end and a second end, wherein the tooth is mounted on the base at the first end. The stator segment further includes a stator winding disposed around the teeth and a resilient element disposed between the stator winding and the base. The present disclosure also relates to a method for assembling a stator segment.

Description

Technical Field

[0001] The present disclosure relates to a stator segment for an electric machine and a method for assembling a stator segment for an electric machine. Background Art

[0002] Modern wind turbines are commonly used to supply electricity to an electrical grid. Wind turbines of this type generally comprise a tower and a rotor arranged on the tower. The rotor, which generally comprises a hub and a plurality of blades, is arranged to rotate under the influence of the wind on the blades. The rotation generates a torque, which is generally transmitted to a generator via a rotor shaft either directly ("direct drive" or "gearless") or by using a gearbox. In this way, the generator produces electricity that can be supplied to an electrical grid.

[0003] Wind turbine generators and other electrical machines such as motors generally include a rotor and a stator. The rotor rotates relative to the stator. The rotor may be an internal structure, and the stator may be another structure. The stator may thus radially surround the rotor. Alternatively, in other configurations, the arrangement may be reversed, with the rotor radially surrounding the stator.

[0004] Large generators, such as in modern wind turbines, may be either permanent magnet generators (PMG) or electrically excited generators.

[0005] In the case of a permanent magnet generator (PMG), the permanent magnets (PM) are generally arranged on the rotor, while the winding elements (i.e. coils) are usually included in the stator. Alternatively, the permanent magnets can also be arranged in the stator structure and the winding elements in the rotor structure. Permanent magnet generators are generally considered to be reliable and require less maintenance than other generator types.

[0006] On the other hand, an electrically excited generator generally includes a rotor having a plurality of pole shoes and an excitation winding (i.e., a coil). In use, an electric current is applied to the excitation coil. The applied current produces the polarity of the poles, wherein adjacent poles have different magnetic polarities. As the rotor rotates, the magnetic field from the pole shoes is applied to the windings of the stator, causing a variable magnetic flux in the stator windings and generating a voltage in the stator windings. Thus, in an electrically excited generator, the magnetic field that generates the electric power is generated electrically, and therefore no permanent magnets are required.

[0007] The electrical winding may be generally arranged in a stator segment. A plurality of stator segments may be connected to the stator edge along the circumference of the stator. The stator segment may include a base configured to be fixed to the stator edge and teeth protruding from the base for receiving the stator winding. The stator winding may be wound around the teeth. The stator segment may include a plurality of teeth and a plurality of stator windings wound around each of the teeth. Thus, the stator winding may be installed to or removed from the stator through the stator segment. The use of the stator segment may facilitate the manufacture of the stator and the replacement of a faulty stator or electrical winding.

[0008] In order to protect the coils and hold them in place, winding stops (or so-called wedges) may be coupled to the respective generator teeth. It is known, for example, to use winding stops (or other winding holding elements) to span the space between adjacent teeth and hold the coils in place between these teeth. However, the assembly process may be time consuming, complicated and cumbersome. In addition, it has been found that the winding stops affect the cooling of the coils in operation.

[0009] The present disclosure provides systems and methods that at least partially overcome some of the above-mentioned disadvantages. Summary of the invention

[0010] In one aspect of the present disclosure, a stator segment for an electric machine is provided. The stator segment includes a base for mounting to a stator structure, and a tooth extending between a first end and a second end, wherein the tooth is mounted on the base at the first end. The stator segment further includes a stator winding arranged around the tooth, and a resilient element arranged between the stator winding and the base.

[0011] According to this aspect, the resilient element mounted between the stator winding and the base can absorb radial movement of the stator winding. The stator winding can be more effectively held against the base, reducing or eliminating the distance between the stator winding and the base, and thus providing an improved path for magnetic flux.

[0012] The mounting of the stator winding to the teeth can also be enhanced, since the stator winding can be securely placed in a relatively simple manner with fewer pieces. In addition, since the teeth are not integrally formed with the base, in some examples, different grades of electrical steel can be used in the two different parts, and losses generated in the stator can be avoided or reduced.

[0013] In another aspect of the present disclosure, a method for assembling a stator segment is provided. The method includes providing a tooth extending between a first end and a second end, and arranging a stator winding around the tooth. The method further includes arranging one or more resilient elements with a base and / or the stator winding, connecting a first end of the tooth to a first end of the base, thereby at least partially retaining the stator winding by the one or more resilient elements, and mounting the tooth to the base at the first end of the tooth.

[0014] In another aspect of the present disclosure, a generator is provided. The generator includes a stator and a rotor, and an air gap radially arranged between the stator and the rotor. The stator includes a stator edge, and a plurality of stator segments according to any of the aforementioned examples of stator segments, wherein the stator segments are attached to the stator edge.

[0015] Additional objects, advantages, and features of the embodiments of the present disclosure will become apparent to those skilled in the art upon examination of the specification, or may be learned through practice. Technical Solution 1. A stator segment (100) for a motor, comprising: a base (110) for mounting to a stator structure (200); a tooth (120) extending between a first end (121) and a second end (122), wherein the tooth (120) is mounted on the base (110) at the first end (121); a stator winding (130) arranged around the teeth (120); and A resilient element (140) is arranged between the stator winding (130) and the base (110). Technical Solution 2. A stator segment (100) according to Technical Solution 1, wherein the tooth (120) includes a first lateral wall and a second lateral wall, and wherein the first lateral wall and the second lateral wall include a protrusion (125) for holding the stator winding (130) at or near the second end (122) of the tooth. Technical Solution 3. The stator segment (100) according to Technical Solution 2, wherein the protrusion (125) is formed integrally with the tooth (120). Technical Solution 4. A stator segment (100) according to any one of Technical Solutions 1 to 3, wherein the resilient element (140) is a corrugated spring. Technical Solution 5. The stator segment (100) according to any one of Technical Solutions 1 to 4 further includes an axially extending rod (150) arranged in the tooth (120) and including a plurality of holes, and wherein the stator segment (100) is fixed to the stator structure (200) by bolts extending through the stator structure (200) and the holes in the axially extending rod (150). Technical Solution 6. The stator segment (100) according to Technical Solution 5, wherein the axially extending rod (150) has a T-shape in an axial cross section. Technical Solution 7. A stator segment (100) according to any one of Technical Solutions 1 to 6, wherein the teeth (120) and the base (110) are made of electrical steel, and wherein the teeth (120) and the base (110) have different grain orientations. Technical Solution 8. A stator segment (100) according to any one of Technical Solutions 1 to 7, wherein the teeth (120) include a plurality of first laminations, and the base (110) includes a plurality of second laminations, and wherein the plurality of first laminations are thinner than the plurality of second laminations. Technical Solution 9. A stator segment (100) according to any one of Technical Solutions 1 to 8, wherein the stator segment (100) includes a plurality of teeth (120) mounted to the base (110), and wherein the teeth (120) include a stator winding (130) surrounding each of the teeth, and the stator segment (100) further includes a resilient element (140) arranged between each of the stator windings (130) and the base (110). Technical Solution 10. A generator, comprising a stator and a rotor, and an air gap radially arranged between the stator and the rotor, wherein the stator comprises: a stator edge (200), and A plurality of stator segments (100) according to any one of technical solutions 1 to 9, wherein the stator segments (100) are mounted to the stator edge (200). Technical Solution 11. A generator according to Technical Solution 10, wherein the generator is a direct-drive wind turbine generator. Technical Solution 12. A generator according to Technical Solution 10, wherein the generator is a permanent magnet generator. Technical solution 13. A method (700) for assembling a stator segment (100), comprising: providing a tooth (120) extending between a first end (121) and a second end (122); providing a base (110) for mounting the tooth (120); Arranging a stator winding (130) around the teeth (120); Arranging one or more resilient elements (140) with the base (110) and / or to the stator windings; coupling the first end (121) of the tooth to the base (110) such that the stator winding (130) is at least partially retained by the one or more resilient elements (140); and The tooth is mounted to the base (110) at a first end (121) of the tooth. Technical Solution 14. A method (700) according to Technical Solution 13, wherein the tooth (120) includes a first lateral wall and a second lateral wall, the first lateral wall and the second lateral wall include a protrusion (125), and wherein connecting the first end (121) of the tooth to the base (110) includes maintaining the stator winding (130) between the protrusion (125) and the one or more resilient elements (140). Technical Solution 15. The method (700) according to Technical Solution 13 or Technical Solution 14 further comprises mounting the stator segment to an edge of a stator of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 schematically illustrates a perspective view of an example of a wind turbine;

[0017] Figure 2 An example of a hub and nacelle of a wind turbine is shown;

[0018] Figure 3 schematically illustrates a perspective view of an example of a stator segment 100 for an electric machine according to the present disclosure;

[0019] Figure 4 Schematically shows Figure 3 A cross section of an example of a stator segment 100 is shown in;

[0020] Figure 5 Schematically shows Figure 1 and Figure 2 A bottom perspective view of a stator segment 100;

[0021] Figure 6 An example of a method for assembling a stator segment 100 is schematically shown; and

[0022] Figure 7 A flow chart of an example of a method for assembling a stator segment 100 is shown. DETAILED DESCRIPTION

[0023] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are shown in the drawings. Each example is provided by way of illustration and not as a limitation. In fact, it will be clear to those skilled in the art that various modifications and variations may be made in the present disclosure without departing from the scope or spirit of the present teachings. For example, a feature shown or described as a part of an embodiment may be used in conjunction with another embodiment to produce yet another embodiment. Therefore, it is expected that the present disclosure covers such modifications and variations as fall within the scope of the appended claims and their equivalents.

[0024] Figure 1is a perspective view of an example of a wind turbine 10. In the example, the wind turbine 10 is a horizontal-axis wind turbine. Alternatively, the wind turbine 10 may be a vertical-axis wind turbine. In this example, the wind turbine 10 includes a tower 15 extending from a support system 14 on the ground 12, a nacelle 16 mounted on the tower 15, and a rotor 18 coupled to the nacelle 16. The rotor 18 includes a rotatable hub 20, and at least one rotor blade 22 coupled to the hub 20 and extending outwardly from the hub 20. In this example, the rotor 18 has three rotor blades 22. In alternative embodiments, the rotor 18 includes more or less than three rotor blades 22. The tower 15 may be made of tubular steel to define a cavity ( Figure 1 1 ). In an alternative embodiment, the tower 15 is any suitable type of tower having any suitable height. According to an alternative, the tower may be a hybrid tower including a portion made of concrete and a tubular steel portion. Moreover, the tower may be a partial or full lattice tower.

[0025] Rotor blades 22 are spaced about hub 20 to facilitate rotating rotor 18 to enable kinetic energy to be converted from the wind into usable mechanical energy and subsequently into electrical energy. Rotor blades 22 are mated to hub 20 by coupling blade root portions 24 to hub 20 at a plurality of load transfer regions 26. Load transfer regions 26 may have hub load transfer regions and blade load transfer regions (both not in the same Figure 1 The loads induced to the rotor blades 22 are transferred to the hub 20 via the load transfer regions 26 .

[0026] In an example, rotor blades 22 may have a length ranging from about 15 meters (m) to about 90 m or more. Rotor blades 22 may have any suitable length that enables wind turbine 10 to operate as described herein. For example, non-limiting examples of blade lengths include 20 m or less, 37 m, 48.7 m, 50.2 m, 52.2 m, or a length greater than 91 m. As wind strikes rotor blades 22 from a wind direction 28, rotor 18 rotates about rotor axis 30. As rotor blades 22 rotate and are subjected to centrifugal forces, rotor blades 22 are also subjected to various forces and moments. Thus, rotor blades 22 may deflect and / or rotate from a neutral position or a non-deflected position to a deflected position.

[0027] In addition, the pitch angle of the rotor blades 22 (i.e., the angle that determines the orientation of the rotor blades 22 relative to the wind direction) can be changed by the pitch system 32 to control the load and the power generated by the wind turbine 10 by adjusting the angular position of at least one rotor blade 22 relative to the wind vector. A pitch axis 34 is shown for the rotor blades 22. During operation of the wind turbine 10, the pitch system 32 can specifically change the pitch angle of the rotor blades 22 so that the angle of attack of (portions of) the rotor blades is reduced, which facilitates reducing the rotational speed and / or facilitating stalling of the rotor 18.

[0028] In an example, the blade pitch of each rotor blade 22 is individually controlled by wind turbine controller 36 or by pitch control system 80. Alternatively, the blade pitch for all rotor blades 22 may be controlled simultaneously by the control system.

[0029] Furthermore, in an example, as wind direction 28 changes, nacelle 16 may be rotated about yaw axis 38 to position rotor blades 22 relative to wind direction 28 .

[0030] In the example, the wind turbine controller 36 is shown as being centralized within the nacelle 16, however, the wind turbine controller 36 may be a distributed system throughout the wind turbine 10, on the support system 14, within the wind farm, and / or at a remote control center. The wind turbine controller 36 includes a processor 40 configured to perform the methods and / or steps described herein. In addition, many of the other components described herein include a processor.

[0031] As used herein, the term "processor" is not limited to the integrated circuits known in the art as computers, but broadly refers to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application specific integrated circuits, and other programmable circuits, and these terms are used interchangeably herein. It should be understood that the processor and / or control system may also include memory, input channels, and / or output channels.

[0032] Figure 21 is an enlarged cross-sectional view of a portion of a wind turbine 10. In the example, the wind turbine 10 includes a nacelle 16 and a rotor 18 rotatably coupled to the nacelle 16. More specifically, the hub 20 of the rotor 18 is rotatably coupled to a generator 42 positioned within the nacelle 16 by a main shaft 44, a gearbox 46, a high-speed shaft 48, and a coupling 50. In the example, the main shaft 44 is at least partially disposed coaxially with a longitudinal axis (not shown) of the nacelle 16. The rotation of the main shaft 44 drives the gearbox 46, which then drives the high-speed shaft 48 by converting relatively slow rotational movement of the rotor 18 and the main shaft 44 into relatively fast rotational movement of the high-speed shaft 48. The latter is connected to the generator 42 by means of a coupling 50 for generating electrical energy. In addition, a transformer 90 and / or suitable electronic devices, switches and / or inverters may be arranged in the nacelle 16 to convert the electrical energy generated by the generator 42 having a voltage between 400 V and 1000 V into electrical energy having a medium voltage (e.g., 10-35 KV). The electrical energy is conducted from the nacelle 16 to the tower 15 via power cables.

[0033] The gearbox 46, the generator 42 and the transformer 90 may be supported by the main support structural frame of the nacelle 16, which may optionally be embodied as a main frame 52. The gearbox 46 may include a gearbox housing connected to the main frame 52 by one or more torque arms 103. In this example, the nacelle 16 also includes a main front support bearing 60 and a main rear support bearing 62. Furthermore, the generator 42 may be mounted to the main frame 52 by a separate support device 54, in particular in order to prevent vibrations of the generator 42 from being introduced into the main frame 52 and thereby causing a source of noise emission.

[0034] Optionally, the main frame 52 is configured to carry all loads caused by the weight of the components of the rotor 18 and the nacelle 16 and by wind and rotational loads, and also introduce these loads into the tower 15 of the wind turbine 10. The rotor shaft 44, the generator 42, the gearbox 46, the high-speed shaft 48, the coupling 50, and any associated fastening, support, and / or fixing devices (including but not limited to the main frame 52 and the front and rear support bearings 60, 62) are sometimes referred to as the drive train 64.

[0035] In some examples, the wind turbine may be a direct drive wind turbine without a gearbox 46. In a direct drive wind turbine, the generator 42 operates at the same rotational speed as the rotor 18. Therefore, they generally have a much larger diameter than the generators used in wind turbines with a gearbox 46 for providing a similar amount of electrical power as a wind turbine with a gearbox.

[0036] The nacelle 16 may also include a yaw drive mechanism 56 that may be used to rotate the nacelle 16 , and thereby the rotor 18 , about the yaw axis 38 to control the projection of the rotor blades 22 relative to the wind direction 28 .

[0037] In order to properly position the nacelle 16 relative to the wind direction 28, the nacelle 16 may also include at least one meteorological measurement system 58, which may include a wind vane and anemometer. The meteorological measurement system 58 may provide information to the wind turbine controller 36, which may include the wind direction 28 and / or the wind speed. In an example, the pitch system 32 is at least partially arranged as a pitch assembly 66 in the hub 20. The pitch assembly 66 includes one or more pitch drive systems 68 and at least one sensor 70. Each pitch drive system 68 is coupled to a corresponding rotor blade 22 ( Figure 1 ), for adjusting the pitch angle of rotor blades 22 along pitch axis 34 . Figure 2 Only one of three pitch drive systems 68 is shown.

[0038] In this example, pitch assembly 66 includes at least one pitch bearing 72 coupled to hub 20 and to a corresponding rotor blade 22 ( Figure 1 ), for rotating the corresponding rotor blade 22 about the pitch axis 34. Pitch drive system 68 includes a pitch drive motor 74, a pitch drive gearbox 76, and a pitch drive pinion 78. Pitch drive motor 74 is coupled to pitch drive gearbox 76 so that pitch drive motor 74 applies mechanical force to pitch drive gearbox 76. Pitch drive gearbox 76 is coupled to pitch drive pinion 78 so that pitch drive pinion 78 is rotated by pitch drive gearbox 76. Pitch bearing 72 is coupled to pitch drive pinion 78 so that rotation of pitch drive pinion 78 causes rotation of pitch bearing 72.

[0039] Pitch drive system 68 is coupled to wind turbine controller 36 for adjusting the pitch angle of rotor blades 22 upon receiving one or more signals from wind turbine controller 36. In an example, pitch drive motor 74 is any suitable motor driven by an electrical and / or hydraulic system that enables pitch assembly 66 to operate as described herein. Alternatively, pitch assembly 66 may include any suitable structure, construction, arrangement, and / or components, such as, but not limited to, a hydraulic cylinder, a spring, and / or a servo mechanism. In certain embodiments, pitch drive motor 74 is driven by energy extracted from the rotational inertia of hub 20 and / or a stored energy source (not shown) that supplies energy to components of wind turbine 10.

[0040] The pitch assembly 66 may also include one or more pitch control systems 80 for controlling the pitch drive system 68 according to control signals from the wind turbine controller 36 in the event of certain priority situations and / or during overspeed of the rotor 18. In an example, the pitch assembly 66 includes at least one pitch control system 80 that is communicatively coupled to a respective pitch drive system 68 for controlling the pitch drive system 68 independently of the wind turbine controller 36. In an example, the pitch control system 80 is coupled to the pitch drive system 68 and to the sensor 70. During normal operation of the wind turbine 10, the wind turbine controller 36 may control the pitch drive system 68 to adjust the pitch angle of the rotor blades 22.

[0041] According to an embodiment, a generator 84, for example including a battery and a capacitor, is arranged at or within the hub 20 and is coupled to the sensor 70, the pitch control system 80, and to the pitch drive system 68 to provide power to these components. In an example, the generator 84 provides a continuous power supply to the pitch assembly 66 during operation of the wind turbine 10. In an alternative embodiment, the generator 84 provides power to the pitch assembly 66 only during a power loss event of the wind turbine 10. The power loss event may include a loss or drop in the power grid, a failure of the electrical system of the wind turbine 10, and / or a failure of the wind turbine controller 36. During the power loss event, the generator 84 operates to provide power to the pitch assembly 66 so that the pitch assembly 66 can operate during the power loss event.

[0042] In the example, pitch drive system 68, sensor 70, pitch control system 80, cables, and generator 84 are each positioned in a cavity 86 defined by an inner surface 88 of hub 20. In alternative embodiments, the components are positioned relative to an outer top deck surface of hub 20 and may be coupled directly or indirectly to the outer top deck surface.

[0043] Figure 3 shows a perspective view of an example of a stator segment 100 for an electric machine according to the present disclosure, and Figure 4 The stator structure 200 ( Figure 3 (not shown) Figure 3 A cross section of an example of a stator segment 100 is shown in FIG. Figure 4 In the example of FIG. 2 , the stator structure 200 may include a stator edge.

[0044] As schematically shown in these figures, the stator segment 100 comprises a base 110 for mounting to a stator structure 200 and a tooth 120 extending between a first end 121 and a second end 122, wherein the tooth 120 is mounted on the base 110 at the first end 121. The stator segment 100 further comprises a stator winding 130 arranged around the tooth 120 and a resilient element 140 arranged between the stator winding 130 and the base 110.

[0045] A small number of sections may be used to effectively hold the stator windings of the stator segments, provide a reduced gap between the stator windings and the base and enhance the magnetic flux path.

[0046] like Figure 3 and Figure 4 As can be seen in FIG. 1 , the base 110 and the teeth 120 are not formed integrally.

[0047] The base 110 for mounting to the stator structure 200 may include a generally U-shaped cross-section and may extend in the longitudinal direction of the tooth 120. In some examples, the length of the base 110 may be substantially the same as the longitudinal length of the first end of the tooth 121. The base 110 may include a first base end 111, which may be configured to be mounted to the stator structure 200.

[0048] In addition, the base 110 may include a first inner lateral base wall 113 and a second inner lateral base wall 115 that define a cavity configured to receive the first end 121 of the tooth. Figure 4 As shown in the example of , the first inner lateral base wall 113 and the second inner lateral base wall 115 can be parallel to each other. In other examples, the first inner lateral base wall 113 and the second inner lateral base wall 115 can include different angles relative to the first base end 111.

[0049] Additionally, the base 110 may include a plurality of holes extending in an axial direction and configured to receive mechanical fasteners.

[0050] Figure 5 Shows Figure 3 A bottom perspective view of a stator segment 100 is shown in FIG. Figure 5 As can be appreciated, the base may include a plurality of first holes that may be used to mechanically secure the assembled stator segment 100 to the stator structure 200 (eg, using one or more bolts).

[0051] In some examples, the base 110 may include a plurality of second holes that can be used to mechanically secure the base 110 to the first end 121 of the tooth. The stator segment 100 may include a base 110 having a plurality of second holes that can be aligned with a plurality of holes arranged in the tooth. That is, in these embodiments, the second holes can be used to secure and hold one / more teeth to the base, while the first holes are used to secure the assembly to the stator structure, such as a stator edge.

[0052] Figure 5 The example shown in shows that the base may include ten holes that may be used to secure or mount the assembled stator segment 100 to the stator rim 200 , and three holes that may be used to secure the teeth 120 to the base 110 and thereby assemble the stator segment 100 .

[0053] Return to reference Figure 4 , the tooth 120 of the stator segment 100 extends between a first end 121 and a second end 122. The tooth 120 may include a first lateral wall and a second lateral wall, and the stator winding 130 may be arranged around the first lateral wall and the second lateral wall.

[0054] During operation of the electric machine, the stator windings 130 are generally subject to tangential and radial movements and forces, and effective retention of the stator windings 130 wound around the teeth 120 is important for optimal operation of the electric machine.

[0055] The first and second lateral walls of the tooth 120 may include a protrusion 125 for retaining the stator winding 130 at or near the second end (122) of the tooth. The protrusion 125 may be integrally formed with the tooth 120 and may be substantially perpendicular to the lateral walls of the tooth 120. Figure 4 As shown in the example of , the protrusion 125 may extend toward the outer side of the stator winding 130 toward the wall 131, for example, along 50%-75% of the thickness of the stator winding 130. In some examples, the protrusion 125 may be located at the second end 122 of the tooth. Compared with some prior art solutions, in this example, the protrusion is formed in one piece, which can reduce the risk of movement or deformation of the protrusion.

[0056] The stator winding 130 of the stator segment 100 may be effectively held between the protrusion 125 and the resilient element 140 , and radial and tangential displacement of the stator winding 130 may be prevented.

[0057] The first end 121 of the tooth can be configured to be received within a cavity defined by the first and second inner lateral base walls 113, 115. In some examples, the first and second lateral walls of the tooth can be parallel to each other and the first end 121 of the tooth can include a substantially rectangular cross-section.

[0058] In some examples, the width of the first end 121 of the tooth may be slightly greater than the distance between the first inner lateral base wall 113 and the second inner lateral base wall 115. The first lateral wall 121 and the second lateral wall 122 of the tooth may be in contact with the first inner lateral base wall 113 and the second inner lateral base wall 115, i.e., pressed against them, so that there is no gap between them and an optimal magnetic flux path is obtained. In some examples, the base may have a certain flexibility, such as a center cutout, which allows the base to move slightly outward when the tooth is inserted into the base. In some examples, the tooth may have a certain flexibility, such as a center cutout, to be slightly compressed inward when inserted into the base. In other examples, both the base and the tooth may have a certain flexibility to facilitate assembly of the two.

[0059] In other examples, the first end 121 of the tooth may include a tapered shape that may fit into a cavity of the base 110 defined by the first and second inboard base walls 113 , 115 .

[0060] The tooth 120 may include one or more grooves extending substantially in the axial direction.

[0061] In some examples, the first end 121 of the tooth can be mounted to the base 110 using a mechanical fastener. The mechanical fastener can extend from the first base end 111 to the groove of the tooth 120. In some examples, an axially extending rod 150 can be arranged in the tooth 120. The axially extending rod 150 can include a plurality of holes, and the stator segment 100 can be fixed to the stator structure 200 by bolts extending through the holes in the stator structure 200 and the axially extending rod 150. In some examples, the same axially extending rod 150 can be used to assemble one / more teeth with the base.

[0062] In some examples, the axially extending rod 150 may have a T-shape in axial cross-section. When a bolt is tightened through the hole in the axially extending rod, the teeth may be pulled toward the base, and an enhanced fixation between the teeth and the base may be achieved.

[0063] In some examples, the teeth 120 and the base 110 may be manufactured in different manufacturing processes, allowing for the development of new modes of industrialization of the stator segment 100 .

[0064] The teeth 120 and the base 110 may be made of electrical steel (eg, silicon steel). In some examples, the same electrical steel may be used in the teeth 120 and in the base 110. In other examples, the teeth 120 and the base 110 may be made of different electrical steels.

[0065] In an electric machine, the magnetic flux in the teeth may have a different direction than the magnetic flux in the base of the stator segment. By using electrical steel with a grain orientation in the same direction as the magnetic flux, improved performance of the electric machine may be achieved. In some examples, the electrical steel from the base and the teeth may have different grain orientations.

[0066] The teeth 120 may be made of grain-oriented electrical steel oriented in a radial direction, and the base 110 may be made of grain-oriented electrical steel oriented in a tangential direction.A stator segment having an enhanced magnetic flux path may be provided.

[0067] Additionally, the teeth 120 and the base 110 may be made from electrical steel laminations, which may minimize power and energy losses, such as by reducing hysteresis losses or eddy currents.

[0068] In some examples, the tooth 120 may include a plurality of first laminations, and the base 110 may include a plurality of second laminations. The plurality of first laminations may be thinner than the plurality of second laminations. In the stator segment, the base 110 may receive less magnetic flux than the tooth 120. Using thicker laminations in the base 110 may provide an easier and faster base manufacturing process, and may also reduce the cost of the stator segment.

[0069] Figure 4 A resilient element 140 is shown disposed between the stator winding 130 and the base 110. In some examples, the resilient element 140 may be a corrugated spring, although other elastic elements may also be used. The resilient element 140 may compress and absorb any radial movement of the stator winding 130 (e.g., due to thermal expansion of the stator winding 130), thereby effectively retaining the stator winding 130 in the stator segment 100.

[0070] In some examples, the resilient element 140 may contact the stator winding 130 along at least 70%-85% of the thickness of the stator winding.

[0071] In some examples, the resilient element 140 may be coupled to the base 110 of the stator segment 100. The resilient element 140 may be coupled to the base 110 by means of gluing. In other examples, the resilient element 140 may be coupled to the stator winding 130.

[0072] In further examples, the stator segment 100 can include one or more shims between the base 110 and the stator winding 130. The one or more shims can facilitate contact between the resilient element 140 and the stator winding 130.

[0073] In some examples (not shown), the stator segment 100 may include a plurality of teeth 120 mounted on a base 110. The stator segment may include a stator winding 130 disposed around each of the teeth, and a resilient element disposed between each of the stator windings 130 and the base 110.

[0074] The plurality of teeth may include the features discussed during this disclosure and may be in the same Figure 3-5 The teeth 120 discussed in are mechanically attached to the base 110 in a similar manner.

[0075] Figure 6 Steps according to an example of a method 700 for assembling a stator segment 100 are schematically illustrated. Figure 7 A flow chart of method 700 is shown in FIG.

[0076] The method 700 includes, at step 702, providing a tooth 120 extending between a first end 121 and a second end 122. As previously described in Figure 4 As discussed in , the tooth 120 may include a protrusion 125 at or near the second end 122 that may be used to retain a stator winding disposed around the tooth. The protrusion may be integrally formed with the tooth.

[0077] The method further includes, at step 704, providing a base for mounting the tooth, and at step 706, arranging the stator winding 130 around the tooth 120. The tooth may include a groove extending substantially in the axial direction of the tooth, and as shown in FIG. Figure 6 As shown in , the method may further include arranging an axially extending rod, such as a T-shaped rod, within the tooth.

[0078] Factors such as temperature, operating conditions, or time may affect the life of the stator windings 130 arranged in the stator segments 100. Therefore, the stator windings 130 may be immersed in a resin or varnish in a process called vacuum pressure impregnation (VPI). After VPI, the stator windings may include higher dielectric strength, greater mechanical strength, improved thermal conductivity, and better protection against foreign substances such as liquids or gases. All of these factors contribute to a longer service life of the stator windings.

[0079] The present method may provide new manufacturing possibilities and VPI may be performed at different stages of the assembly process.In some examples, the method may include performing vacuum pressure infiltration after the stator windings have been arranged around the teeth.

[0080] Step 708 of the method includes arranging one or more resilient elements 140 with the base and / or to the stator windings. In some examples, the resilient elements may be attached to the base or the stator windings. In one example, the resilient elements may be glued to the base.

[0081] Furthermore, step 710 of the method for assembling a stator segment includes coupling a first end of the tooth 121 to the base 110 , thereby retaining the stator winding 130 at least partially via the one or more resilient elements 140 .

[0082] The first end of the tooth 121 may be introduced into a cavity defined by the first inner lateral base wall 13 and the second inner lateral base wall 115. In some examples, the width of the first end of the tooth 121 may be slightly less than the width of the cavity of the base, and the method may include introducing the first end of the tooth 121 into the cavity of the base with substantially no friction between the two parts.

[0083] In some examples, coupling the first end 121 of the tooth to the first end of the base may include holding the stator winding 130 between the protrusion 125 and one or more resilient elements 140. The resilient elements 140 may be held between the base 110 and the stator winding 130 simultaneously.

[0084] In some examples, vacuum pressure impregnation (VPI) may be performed after the first end of the tooth has been joined to the base.Thus, with the present method, flexibility during assembly of the stator segment may be provided.

[0085] Finally, step 712 of the method includes mounting the tooth to the base at the first end of the tooth. Figure 6 As schematically shown in , the first end 121 of the tooth may be mounted to the base 110 using mechanical fasteners such as bolts, and thus an assembled stator segment 100 is obtained.

[0086] In some examples, the method may include aligning a plurality of second holes in the base with a plurality of holes in the axially extending rod within the tooth and fastening the mechanical fastener through the aligned holes.

[0087] In other examples, the width of the first end of the tooth 121 may be slightly wider than the width of the cavity, and the tooth 120 and the base 110 may be attached by an interference fit. The tooth 120 and the base 110 may be attached together due to friction therebetween, avoiding the use of additional mechanical fasteners.

[0088] In further examples, multiple teeth may be provided to be coupled to the same base. In these examples, the method may include arranging the stator winding 130 around each of the teeth and coupling and mounting the teeth to the base at a first end of the tooth.

[0089] In a further step, the method may include mounting the assembled stator segment 100 to the stator structure 200 (eg, a stator rim). In some examples, the stator segment 100 may be mounted to the stator structure 200 using mechanical fasteners.

[0090] In another aspect of the present disclosure, a generator is provided. The generator includes a stator and a rotor. According to any of the previously discussed examples, the generator further includes a stator rim 200 and a plurality of stator segments 100 . The stator segments 100 are mounted to the stator rim 200 .

[0091] In some examples, the generator may be a direct wind turbine generator. In other examples, the generator may be a permanent magnet generator.

[0092] It should be noted that although the disclosed examples relate to wind turbine generators, the teachings of the present disclosure may also be applied to other generators, such as hydroelectric generators or steam turbines, and other electrical machines, such as motors.

[0093] This written description uses examples, including preferred embodiments, to disclose the present teachings, and also enables any person skilled in the art to practice the present teachings, including making and using any device or system, and performing any incorporated method. The scope of the patentable invention is defined by the claims, and may include other examples that occur to those skilled in the art. If such other examples have structural elements that are not different from the written language of the claims, or if they include equivalent structural elements that are not substantially different from the written language of the claims, such other examples are expected to be within the scope of the claims. Aspects from the various embodiments described, as well as other known equivalents for each such aspect, can be mixed and matched by a person of ordinary skill in the art to form additional embodiments and techniques according to the principles of the present application. If reference marks associated with the drawings are placed in brackets in the claims, they are only used to attempt to increase the understandability of the claims and should not be interpreted as limiting the scope of the claims.

Claims

1. A stator segment (100) for an electric machine, comprising: a base (110) for mounting to a stator structure (200); a tooth (120) extending between a first end (121) and a second end (122), wherein the tooth (120) is mounted on the base (110) at the first end (121); a stator winding (130) arranged around the teeth (120); and A resilient element (140) is arranged between the stator winding (130) and the base (110).

2. The stator segment (100) according to claim 1, wherein: The tooth (120) includes a first lateral wall and a second lateral wall, and wherein the first lateral wall and the second lateral wall include a protrusion (125) for retaining the stator winding (130) at or near the second end (122) of the tooth.

3. The stator segment (100) according to claim 2, wherein: The protrusion (125) is formed integrally with the tooth (120).

4. The stator segment (100) according to any one of claims 1 to 3, wherein: The resilient element (140) is a corrugated spring.

5. The stator segment (100) according to any one of claims 1 to 4, further comprising an axially extending rod (150) arranged within the teeth (120) and comprising a plurality of holes, and wherein the stator segment (100) is fixed to the stator structure (200) by bolts extending through the stator structure (200) and the holes in the axially extending rod (150).

6. The stator segment (100) according to claim 5, wherein: The axially extending rod (150) has a T-shape in an axial cross section.

7. The stator segment (100) according to any one of claims 1 to 6, wherein: The teeth (120) and the base (110) are made of electrical steel, and wherein the teeth (120) and the base (110) have different grain orientations.

8. The stator segment (100) according to any one of claims 1 to 7, wherein: The tooth (120) includes a first plurality of laminations, and the base (110) includes a second plurality of laminations, and wherein the first plurality of laminations are thinner than the second plurality of laminations.

9. The stator segment (100) according to any one of claims 1 to 8, wherein: The stator segment (100) comprises a plurality of teeth (120) mounted to the base (110), and wherein the teeth (120) comprise a stator winding (130) surrounding each of the teeth, the stator segment (100) further comprising a resilient element (140) disposed between each of the stator windings (130) and the base (110).

10. A generator comprising a stator and a rotor, and an air gap radially arranged between the stator and the rotor, wherein the stator comprises: a stator edge (200), and A plurality of stator segments (100) according to any one of claims 1 to 9, wherein the stator segments (100) are mounted to the stator rim (200).

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