Stator segment for electrical machine and assembly method

Abstract

To provide a stator segment for electrical machines.SOLUTION: A stator segment includes a base for mounting to a stator structure, and a tooth extending between a first end and a second end. 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. The present disclosure also relates to a method for assembling stator segments.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE 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 technology]

[0002] Modern wind turbines are commonly used to provide electricity to the power grid. This type of wind turbine typically includes a tower and a rotor disposed on the tower. The rotor typically includes a hub and a number of blades, which rotate under the influence of wind on the blades. This rotation generates a torque, which is typically transferred via the rotor shaft to a generator, either directly ("direct drive" or "gearless") or using a gearbox. In this way, the generator generates electricity, which can be provided to the power grid.

[0003] Wind turbine generators, and other electric machines such as motors, typically include a rotor and a stator. The rotor rotates relative to the stator. Sometimes the rotor is the inner structure and the stator is the other structure. Thus, the stator may radially surround the rotor. Alternatively, in other configurations the arrangement is reversed, with the rotor radially surrounding the stator.

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

[0005] In a permanent magnet generator (PMG), the permanent magnets (PM) are typically located in the rotor and the winding elements or coils are usually contained in the stator. Alternatively, the permanent magnets can be located in the stator structure and the winding elements in the rotor structure. Permanent magnet generators are generally considered to be more reliable and require less maintenance than other generator types.

[0006] On the other hand, electrically excited generators typically include a rotor having a number of pole shoes and an excitation winding or coil. In use, a current is applied to the excitation coil. The applied current creates a polarity of the poles, with adjacent poles having different magnetic polarities. As the rotor rotates, a magnetic field from the pole shoes is applied to the stator windings, generating a variable magnetic flux in the stator windings, which generates a voltage in the stator windings. Thus, in an electrically excited generator, no permanent magnets are required, since the magnetic field that generates power is created electrically.

[0007] The electrical windings may generally be disposed on stator segments. A number of stator segments may be connected to a stator rim along the stator circumference. The stator segments may comprise a base configured to be fixed to the stator rim and teeth protruding from the base for receiving the stator windings. The stator windings may be wound on the teeth. The stator segments may be comprised of a number of teeth and a number of stator windings wound on each tooth. Thus, the stator windings may be attached to or removed from the stator via the stator segments. The use of stator segments may facilitate the manufacture of the stator or the replacement of a faulty stator or electrical winding.

[0008] To protect the coils and hold them in place, winding stops (or so-called wedges) may be coupled to each generator tooth. For example, it is known to use winding stops (or other winding retention elements) that span the space between adjacent teeth and hold the coils in place between those teeth. However, the assembly process can be time consuming, complicated, and tedious. Also, winding stops have been found to affect the cooling of the coils during operation.

[0009] The present disclosure provides systems and methods that at least partially overcome some of the aforementioned shortcomings. Summary of the Invention

[0010] In one aspect of the disclosure, a stator segment for an electrical machine is provided, the stator segment including a base for mounting to a stator structure and a tooth extending between a first end and a second end, the tooth is mounted on the base at the first end, the stator segment further including 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 installed between the stator winding and the base may absorb radial movement of the stator winding. The stator winding may be retained more effectively against the base, reducing or eliminating a distance between the stator winding and the base and therefore providing an improved path for the magnetic flux.

[0012] The attachment of the stator windings to the teeth is also improved because the stator windings can be reliably positioned in a relatively simple manner with fewer parts. Furthermore, because the teeth and base are not integrally formed, in some embodiments different grades of electrical steel can be used for the two different parts, avoiding or reducing losses in the stator.

[0013] In another aspect of the disclosure, a method of assembling a stator segment is provided, the method comprising providing teeth extending between a first end and a second end and disposing a stator winding around the teeth, the method further comprising disposing one or more resilient elements with a base and / or the stator winding, joining first ends of the teeth to a first end of the base with the stator winding at least partially held by the one or more resilient elements, and attaching the teeth to the base at the first ends of the teeth.

[0014] In a further aspect of the present disclosure, a generator is provided that includes a stator, a rotor, and an air gap disposed radially between the stator and the rotor, the stator including a stator rim and a plurality of stator segments according to any of the stator segment examples described above, the stator segments being attached to the stator rim.

[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 by practice. [Brief description of the drawings]

[0016] [Figure 1] 1 illustrates a schematic perspective view of an example wind turbine; [Diagram 2] An example of a wind turbine hub and nacelle is shown. [Diagram 3] 1 shows a schematic perspective view of an example of a stator segment 100 for an electric machine according to the present disclosure. [Figure 4] 4 illustrates a schematic cross-section of the example stator segment 100 shown in FIG. [Diagram 5] 3 shows a schematic bottom perspective view of the stator segment 100 of FIGS. 1 and 2. FIG. [Figure 6] 1 illustrates, in schematic form, an example of how the stator segments 100 may be assembled. [Figure 7]2 shows a flow chart of an example method for assembling the stator segments 100. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Reference will now be made in detail to the embodiments of the present disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation and not by way of limitation. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the teachings. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still further embodiments. Thus, it is intended that the present disclosure cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0018] FIG. 1 is a perspective view of an example of a wind turbine 10. In this 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 a ground 12, a nacelle 16 attached to 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 fabricated from tubular steel to define a cavity (not shown in FIG. 1) between the support system 14 and the nacelle 16. In alternative embodiments, the tower 15 may be any suitable type of tower having any suitable height. According to an alternative, the tower may be a hybrid tower made of concrete and steel tubular sections. It may also be a partial or complete lattice tower.

[0019] The rotor blades 22 are spaced relative to the hub 20 to facilitate rotating the rotor 18 and enabling kinetic energy to be transferred from the wind to usable mechanical energy and then to electrical energy. The rotor blades 22 are mated to the hub 20 by coupling blade root portions 24 to the hub 20 at a number of load transfer regions 26. The load transfer regions 26 may include hub load transfer regions and blade load transfer regions (both not shown in FIG. 1 ). Loads induced in the rotor blades 22 are transferred to the hub 20 via the load transfer regions 26.

[0020] In an embodiment, the rotor blades 22 may have a length ranging from about 15 meters (m) to about 90 meters (m) or more. The rotor blades 22 may have any suitable length that enables the wind turbine 10 to function as described herein. For example, non-limiting examples of blade lengths include lengths of 20 meters or less, 37 meters (m), 48.7 meters (m), 50.2 meters (m), 52.2 meters (m), or more than 91 meters (m). When wind strikes the rotor blades 22 from a wind direction 28, the rotor 18 rotates about the rotor axis 30. As the rotor blades 22 rotate and experience centrifugal forces, the rotor blades 22 also experience various forces and moments. As such, the rotor blades 22 may deflect and / or rotate from a neutral, or unbiased, position to a biased position.

[0021] Furthermore, the pitch angle of the rotor blades 22, i.e., the angle determining the orientation of the rotor blades 22 with respect to the wind direction, may be varied by the pitch system 32 to control the load and power generated by the wind turbine 10 by adjusting the angular position of at least one rotor blade 22 with respect to the wind vector. A pitch axis 34 of the rotor blades 22 is shown. During operation of the wind turbine 10, the pitch system 32 may vary the pitch angle of the rotor blades 22, in particular to reduce the angle of attack of (some of) the rotor blades, thereby facilitating a reduction in rotational speed and / or facilitating a stall of the rotor 18.

[0022] In an embodiment, the blade pitch of each rotor blade 22 is individually controlled by the wind turbine controller 36 or the pitch control system 80. Alternatively, the blade pitch of all rotor blades 22 may be simultaneously controlled by these control systems.

[0023] Further, in the illustrative embodiment, as wind direction 28 changes, nacelle 16 may be rotated about yaw axis 38 to position rotor blades 22 relative to wind direction 28 .

[0024] In the illustrative embodiment, wind turbine controller 36 is shown as centralized in nacelle 16, however, wind turbine controller 36 may be a distributed system throughout wind turbine 10, on support system 14, in a wind farm, and / or in a remote control center. Wind turbine controller 36 includes a processor 40 configured to perform the methods and / or steps described herein. Additionally, many of the other components described herein include a processor.

[0025] As used herein, the term "processor" is not limited to integrated circuits referred to in the art as computers, but refers broadly to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application specific, integrated circuits, and other programmable circuitry, and these terms are used interchangeably herein. It should be understood that a processor and / or control system may also include memory, input channels, and / or output channels.

[0026] 2 is an enlarged cross-sectional view of a portion of the wind turbine 10. In this example, the wind turbine 10 includes a nacelle 16 and a rotor 18 rotatably coupled to the nacelle 16. More specifically, a hub 20 of the rotor 18 is rotatably coupled to a generator 42 disposed within the nacelle 16 by a main shaft 44, a gearbox 46, a high-speed shaft 48, and a coupling 50. In this example, the main shaft 44 is disposed at least partially coaxially with a longitudinal axis (not shown) of the nacelle 16. Rotation of the main shaft 44 drives a gearbox 46, which drives the high-speed shaft 48 by converting the relatively slow rotational motion of the rotor 18 and main shaft 44 into a relatively fast rotational motion of the high-speed shaft 48. The latter is connected, with the aid of the coupling 50, to a generator 42 for producing electrical energy. Further, a transformer 90 and / or appropriate electronics, switches, and / or inverters may be disposed within the nacelle 16 to convert the electrical energy generated by the generator 42 having a voltage of 400V-1000V into electrical energy having a medium voltage, for example 10-35 KV. The electrical energy is conducted from the nacelle 16 to the tower 15 via a power cable.

[0027] The gearbox 46, the generator 42, and the transformer 90 may be supported by a main support structural frame of the nacelle 16, optionally embodied as a main frame 52. The gearbox 46 may include a gearbox housing coupled to the main frame 52 by one or more torque arms 103. In an embodiment, the nacelle 16 also includes a main forward support bearing 60 and a main aft support bearing 62. Furthermore, the generator 42 may be mounted to the main frame 52 by a decoupling support means 54, particularly to prevent vibrations of the generator 42 from being introduced into the main frame 52 and thereby causing a source of noise emissions.

[0028] Optionally, the main frame 52 is configured to carry the weight of the rotor 18 and nacelle 16 components, as well as the overall loads caused by wind and rotational loads, and to introduce these loads into the tower 15 of the wind turbine 10. The rotor shaft 44, generator 42, gearbox 46, high speed shaft 48, coupling 50, and main frame 52, and any associated fastening, supporting, and / or fastening devices, including, but not limited to, forward support bearing 60 and aft support bearing 62, may be referred to as a drive train 64.

[0029] In some examples, the wind turbine may be a direct drive wind turbine without a gearbox 46. The generator 42 operates at the same rotational speed as the rotor 18 of a direct drive wind turbine and therefore generally has a much larger diameter than the generator used in a wind turbine with a gearbox 46 to provide the same amount of power as a wind turbine with a gearbox 46.

[0030] 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 approach or approach of the rotor blades 22 relative to the wind direction 28.

[0031] To properly position the nacelle 16 with respect 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 including the wind direction 28 and / or wind speed to the wind turbine controller 36. In this embodiment, the pitch system 32 is at least partially disposed within the hub 20 as a pitch assembly 66. The pitch assembly 66 includes one or more pitch drive systems 68 and at least one sensor 70. Each pitch drive system 68 is coupled to a respective rotor blade 22 (shown in FIG. 1 ) for modulating the pitch angle of the rotor blade 22 along the pitch axis 34. Only one of the three pitch drive systems 68 is shown in FIG. 2 .

[0032] In an embodiment, pitch assembly 66 includes at least one pitch bearing 72 coupled to hub 20 and each rotor blade 22 (shown in FIG. 1 ) to rotate each rotor blade 22 about pitch axis 34. Pitch drive system 68 includes a pitch drive motor 74, a pitch drive gearbox 76, and a pitch drive pinion 78. Pitch drive motor 74 is coupled to pitch drive gearbox 76 such that pitch drive motor 74 provides a mechanical force to pitch drive gearbox 76. Pitch drive gearbox 76 is coupled to pitch drive pinion 78 such that pitch drive pinion 78 is rotated by pitch drive gearbox 76. Pitch bearing 72 is coupled to pitch drive pinion 78 such that rotation of pitch drive pinion 78 causes rotation of pitch bearing 72.

[0033] The pitch drive system 68 is coupled to the wind turbine controller 36 for adjusting the pitch angle of the rotor blades 22 in response to one or more signals from the wind turbine controller 36. In this example, the pitch drive motor 74 is any suitable motor driven by an electrical power and / or hydraulic system that enables the pitch assembly 66 to function as described herein. Alternatively, the pitch assembly 66 may include any suitable structure, configuration, arrangement, and / or components, such as, but not limited to, hydraulic cylinders, springs, and / or servo mechanisms. In certain embodiments, the pitch drive motor 74 is driven by the rotational inertia of the hub 20 and / or energy extracted from a stored energy source (not shown) that provides energy to components of the wind turbine 10.

[0034] The pitch assembly 66 may also include one or more pitch control systems 80 for controlling the pitch drive systems 68 in accordance with control signals from the wind turbine controller 36 in case of certain preferred conditions and / or during overspeed of the rotor 18. In an example embodiment, the pitch assembly 66 includes at least one pitch control system 80 communicatively coupled to each pitch drive system 68 for controlling the pitch drive systems 68 independently from the wind turbine controller 36. In an example embodiment, the pitch control system 80 is coupled to the pitch drive systems 68 and to the sensors 70. During normal operation of the wind turbine 10, the wind turbine controller 36 may control the pitch drive systems 68 to adjust the pitch angle of the rotor blades 22.

[0035] According to an embodiment, a power generator 84, including, for example, batteries and electrical capacitors, is disposed at or within the hub 20 and is coupled to the sensors 70, the pitch control system 80, and the pitch drive system 68 to provide a source of electrical power to these components. In this example, the generator 84 provides a continuous source of electrical power to the pitch assembly 66 during operation of the wind turbine 10. In an alternative embodiment, the generator 84 provides electrical power to the pitch assembly 66 only during a power loss event of the wind turbine 10. A power loss event may include a loss or dip in the electrical grid, a malfunction of the electrical system of the wind turbine 10, and / or a failure of the wind turbine controller 36. During a power loss event, the generator 84 operates to provide electrical power to the pitch assembly 66 such that the pitch assembly 66 can operate during the power loss event.

[0036] In the illustrative embodiment, pitch drive system 68, sensor 70, pitch control system 80, cables, and generator 84 are each disposed within a cavity 86 defined by an inner surface 88 of hub 20. In alternative embodiments, the components may be positioned relative to an outer roof surface of hub 20 and directly or indirectly coupled to the outer roof surface.

[0037] Figure 3 is a perspective view of an example stator segment 100 for an electric machine according to the present disclosure, and Figure 4 is a cross-sectional view of the example stator segment 100 shown in Figure 3 attached to a stator structure 200 (not shown in Figure 3). In the example of Figure 4, the stator structure 200 can include a stator rim.

[0038] As shown diagrammatically in these figures, the stator segment 100 comprises a base 110 for attachment to a stator structure 200 and teeth 120 extending between a first end 121 and a second end 122, with the teeth 120 attached to the base 110 at the first end 121. The stator segment 100 further comprises a stator winding 130 disposed around the teeth 120 and a resilient element 140 disposed between the stator winding 130 and the base 110.

[0039] The stator windings of the stator segments can be effectively maintained with fewer parts, and the gap between the stator windings and the base can be reduced, improving the magnetic flux path.

[0040] As can be seen in Figures 3 and 4, the base 110 and the teeth 120 are not integrally formed.

[0041] The base 110 for attachment to the stator structure 200 may be configured with a substantially U-shaped cross-section and may extend along the longitudinal direction of the teeth 120. In some examples, the length of the base 110 may be substantially the same as the longitudinal length of the first ends 121 of the teeth. The base 110 may include a first base end 111 that may be configured for attachment to the stator structure 200.

[0042] Additionally, 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. As shown in the example of FIG. 4, the first inner lateral base wall 113 and the second inner lateral base wall 115 may be parallel to one another. In other examples, the first inner lateral base wall 113 and the second inner lateral base wall 115 may be at different angles relative to the first base end 111.

[0043] Additionally, the base 110 may include a number of axially extending holes configured to receive mechanical fasteners.

[0044] Figure 5 is a bottom perspective view of the stator segment 100 shown in Figure 3. As can be seen in Figure 5, the base can include a plurality of first holes that can be used to mechanically secure the assembled stator segment 100 to the stator structure 200, for example with one or more bolts.

[0045] In some examples, the base 110 may include a plurality of second holes that may be used to mechanically secure the base 110 to the first end 121. The stator segment 100 may include a base 110 having a plurality of second holes that may align with a plurality of holes disposed in the teeth. That is, in these embodiments, the second holes are used to secure and hold the teeth / teeth to the base, while the first holes are used to secure the assembly to a stator structure, e.g., a stator rim.

[0046] The embodiment shown in FIG. 5 shows that the base can include ten holes that can be used to secure or attach the assembled stator segments 100 to the stator rim 200, and three holes that can be used to secure the teeth 120 to the base 110, thereby assembling the stator segments 100.

[0047] 4, the teeth 120 of the stator segment 100 extend between a first end 121 and a second end 122. The teeth 120 may include a first sidewall and a second sidewall, and the stator windings 130 may be disposed about the first and second sidewalls.

[0048] During operation of the electric machine, the stator windings 130 are typically subjected to tangential and radial movements and forces, and effective retention of the stator windings 130 wound around the teeth 120 is important for optimal functioning of the electric machine.

[0049] The first and second side walls of the teeth 120 may include protrusions 125 for holding the stator windings 130 at or near the second ends (122) of the teeth. The protrusions 125 may be integrally formed with the teeth 120 and may be substantially perpendicular to the side walls of the teeth 120. As shown in the example of FIG. 4, the protrusions 125 may extend toward the outer side walls 131 of the stator windings 130, for example along 50-75% of the thickness of the stator windings 130. In some examples, the protrusions 125 may be located at the second ends 122 of the teeth. In contrast to some prior art solutions, in this embodiment the protrusions are integrally formed, which may reduce the risk of the protrusions moving or deforming.

[0050] The stator windings 130 of the stator segment 100 may be effectively held between the protrusions 125 and the resilient elements 140 to prevent radial and tangential displacement of the stator windings 130 .

[0051] The first ends 121 of the teeth may be configured to be received within cavities defined by the first inner lateral base wall 113 and the second inner lateral base wall 115. In some examples, the first and second lateral walls of the teeth may be parallel to one another, and the first ends 121 of the teeth may include a substantially rectangular cross-section.

[0052] In some examples, the width of the first end 121 of the teeth may be slightly greater than the distance between the first and second inner lateral base walls 113, 115. The first and second lateral walls 121, 122 of the teeth may be in contact with the first and second inner lateral base walls 113, 115, i.e., pressed against the first and second inner lateral base walls 113, 115, such that there is no gap between them and optimal flux path is obtained. In some examples, the base may have some flexibility, such as a center cut, to allow the base to move slightly outward when the teeth are inserted into the base. In some examples, the teeth may have some flexibility, such as a center cut, to allow the base to compress slightly inward when inserted into the base. In further examples, both the base and the teeth may have some flexibility to facilitate assembly of the two.

[0053] In other examples, the first ends 121 of the teeth may include a tapered shape that may fit into a cavity in the base 110 defined by the first and second inner lateral base walls 113,115.

[0054] The teeth 120 may include one or more grooves extending substantially axially.

[0055] In some embodiments, the first ends 121 of the teeth may be attached to the base 110 using mechanical fasteners. The mechanical fasteners may extend from the first base ends 111 to the grooves of the teeth 120. In some embodiments, an axially extending bar 150 may be disposed within the teeth 120. The axially extending bar 150 may comprise a plurality of holes, and the stator segment 100 may be fixed to the stator structure 200 by bolts extending through the stator structure 200 and the holes in the axially extending bar 150. In some embodiments, the same axially extending bar 150 may be used to assemble one or more teeth to the base.

[0056] In some embodiments, the axially extending bar 150 can have a T-shape in axial cross section. When bolts are tightened through holes in the axially extending bar, the teeth are pulled toward the base and enhanced fixation between the teeth and the base can be achieved.

[0057] In some embodiments, the teeth 120 and the base 110 may be manufactured using different manufacturing processes, allowing for the development of new patterns of industrialization of the stator segments 100.

[0058] Teeth 120 and base 110 may be made from electrical steel, such as silicon steel. In some embodiments, the same electrical steel may be used for teeth 120 and base 110. In other examples, teeth 120 and base 110 may be made from different electrical steels.

[0059] 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 of the base and teeth may have different grain orientations.

[0060] The teeth 120 may be made from radially oriented grain-oriented electrical steel, while the base 110 may be made from tangentially oriented grain-oriented electrical steel. Stator segments with enhanced magnetic flux paths may be provided.

[0061] Additionally, the teeth 120 and base 110 may be made from electrical steel laminations, which may minimize power and energy losses, for example, reducing hysteresis losses or eddy currents.

[0062] In some examples, the teeth 120 may be comprised of a plurality of first laminations and the base 110 may be comprised of a plurality of second laminations. The plurality of first laminations may be thinner than the plurality of second laminations. In a stator segment, the base 110 may receive less magnetic flux than the teeth 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 segments.

[0063] 4 illustrates a resilient element 140 disposed between the stator windings 130 and the base 110. In some embodiments, the resilient element 140 may be a ripple spring, although other resilient elements may be used. The resilient element 140 may compress and absorb radial movement of the stator windings 130, for example due to thermal expansion of the stator windings 130, to effectively hold the stator windings 130 within the stator segment 100.

[0064] In some embodiments, the resilient elements 140 can contact the stator windings 130 along at least 70-85% of the thickness of the stator windings.

[0065] 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 adhesive. In other examples, the resilient element 140 may be coupled to the stator winding 130.

[0066] In further embodiments, the stator segment 100 can include one or more shims between the base 110 and the stator windings 130. The one or more shims can facilitate contact between the resilient element 140 and the stator windings 130.

[0067] In some embodiments (not shown), the stator segment 100 may include a number of teeth 120 attached to a base 110. The stator segment may include a stator winding 130 disposed around each tooth and a resilient element disposed between each stator winding 130 and the base 110.

[0068] The teeth may be constructed with the features discussed in this disclosure and may be mechanically attached to the base 110 in a manner similar to the teeth 120 discussed in FIGS.

[0069] 6 illustrates generally the steps of an example method 700 for assembling the stator segments 100. A flow chart of the method 700 is shown in FIG.

[0070] The method 700, at step 702, comprises providing teeth 120 extending between a first end 121 and a second end 122. As previously described in Figure 4, the teeth 120 may include protrusions 125 at or near the second end 122 that may be used to retain a stator winding disposed about the teeth. The protrusions may be integrally formed with the teeth.

[0071] The method further includes providing a base for mounting the teeth, step 704, and disposing the stator windings 130 around the teeth 120, step 706. The teeth may include grooves extending substantially axially of the teeth, and the method may further include disposing axially extending bars, such as T-shaped bars, within the teeth, as shown in FIG.

[0072] Factors such as temperature, operating conditions, or time can affect the life of the stator windings 130 disposed on 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 have higher dielectric strength, higher mechanical strength, higher thermal conductivity, and better protection against external agents such as fluids and gases. All these factors contribute to a longer life of the stator windings.

[0073] The method can offer new manufacturing possibilities, and VPI can be performed at different stages of the assembly sequence. In some examples, the method can consist of performing vacuum pressure impregnation after the stator windings are placed around the teeth.

[0074] Method step 708 includes disposing one or more resilient elements 140 on the base and / or the stator windings. In some examples, the resilient elements may be bonded to either the base or the stator windings. In one example, the resilient elements may be glued to the base.

[0075] Further, step 710 of the method of assembling the stator segments comprises joining first ends of the teeth 121 to a base 110 that at least partially holds the stator windings 130 by one or more resilient elements 140 .

[0076] The first ends 121 of the teeth may be introduced into cavities defined by the first and second inner lateral base walls 113, 115. In some examples, the width of the first ends 121 of the teeth may be slightly less than the width of the cavity of the base, and the method may include introducing the first ends 121 of the teeth into the cavity of the base with substantially no friction between the two portions.

[0077] In some embodiments, joining the first ends 121 of the teeth to the first end of the base may include holding the stator windings 130 between the protrusions 125 and one or more resilient elements 140. The resilient elements 140 may simultaneously be held between the base 110 and the stator windings 130.

[0078] In some embodiments, the vacuum pressure impregnation (VPI) may be performed after the first ends of the teeth are bonded to the base, thus providing flexibility during assembly of the stator segments.

[0079] Finally, step 712 of the method includes attaching the teeth to the base at first ends of the teeth. As shown diagrammatically in FIG. 6, mechanical fasteners such as bolts can be used to attach the first ends 121 of the teeth to the base 110, thus obtaining the assembled stator segment 100.

[0080] In some examples, the method may include aligning a plurality of second holes in the base with a plurality of holes in an axially extending bar in the tooth and fastening a mechanical fastener through the aligned holes.

[0081] In other embodiments, the width of the first ends 121 of the teeth may be slightly wider than the width of the cavity, and the teeth 120 and base 110 may be attached by an interference fit. The teeth 120 and base 110 may be attached by friction between them, avoiding the use of additional mechanical fasteners.

[0082] In further examples, multiple teeth may be provided that are joined to the same base. In these examples, the method may include disposing a stator winding 130 around each tooth and joining and attaching the teeth to the base at a first end of the teeth.

[0083] In a further step, the method may include attaching the assembled stator segments 100 to a stator structure 200, such as a stator rim. In some examples, the stator segments 100 may be attached to the stator structure 200 using mechanical fasteners.

[0084] In another aspect of the present disclosure, a generator is provided. The generator comprises a stator and a rotor. The generator further comprises a stator rim 200 and a plurality of stator segments 100 according to any of the previously described examples. The stator segments 100 are attached to the stator rim 200.

[0085] In some examples, the generator may be a direct wind turbine generator, while in other examples, the generator may be a permanent magnet generator.

[0086] It should be noted that although the disclosed embodiments relate to wind turbine generators, the teachings of the present disclosure may also be applied to other generators, such as water generators and steam turbines, and other electric machines, such as motors.

[0087] Examples are used herein to disclose the teachings, including preferred embodiments, and to enable one of ordinary skill in the art to practice the teachings, including making and using any device or system, and performing any methods incorporated therein. The patentable scope is defined by the claims, and may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be included in the claims if they have structural elements that do not differ from the language of the claims, or if they include equivalent structural elements that do not differ substantially from the language of the claims. Aspects from the various embodiments described, and other known equivalents to each such aspect, may be mixed and matched by those of ordinary skill in the art to construct additional embodiments and techniques according to the principles of this application. When reference signs related to the drawings are placed in parentheses in the claims, they are merely intended to improve the clarity of the claims, and should not be construed as limiting the scope of the claims. [Explanation of symbols]

[0088] 10:wind turbine 12:ground 14:support system 15:tower 16:nacelle 18:rotor 20:hub 22:rotor blade 24:blade root area 26:load transfer area 28:wind direction 30:rotor shaft 32:pitch system 34:pitch axis 36:wind turbine controller 8:yaw axis 42:generator 44:main shaft 46:gearbox 48:high speed shaft 50:coupling 51:shaft sensor 52:main frame 53:generator sensor 54:decoupling support means 56:yaw drive mechanism 58:meteorological measurement system 60:main forward support bearing 62:main aft support bearing 64:drive train 66:pitch assembly 68:pitch drive system 70:sensor 72:pitch bearing 74:pitch drive motor 76:pitch drive gearbox 78:pitch drive pinion 80:pitch control system 84: power source / generator 86: cavity 88: inner surface 90: transformer 100: stator segment 103: torque arm 110: base 111: first base end 113: first inner lateral base wall 115: second inner lateral base wall 120: teeth 121: first end 122: second end 125: protrusion 130: stator winding 131: stator winding 140: resilient element 150: bar 200: stator structure

Claims

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

2. 2. The stator segment (100) of claim 1, wherein the teeth (120) include a first sidewall and a second sidewall, the first and second sidewalls including protrusions (125) for retaining a stator winding (130) at or near the second ends (122) of the teeth.

3. The stator segment (100) of claim 2, wherein the protrusions (125) are integrally formed with the teeth (120).

4. The stator segment (100) of claim 1, wherein the resilient element (140) is a ripple spring.

5. 2. The stator segment (100) of claim 1, further comprising an axially extending bar (150) disposed within the teeth (120) and including a plurality of holes, the stator segment (100) being secured to the stator structure (200) by bolts extending through the stator structure (200) and the holes in the axially extending bar (150).

6. The stator segment (100) of claim 5, wherein the axially extending bars (150) have a T-shape in axial cross section.

7. The stator segment (100) of claim 1, wherein the teeth (120) and the base (110) are made of an electrical steel, and the teeth (120) and the base (110) have different grain orientations.

8. The stator segment (100) of claim 1, wherein the teeth (120) include a plurality of first laminations and the base (110) includes a plurality of second laminations, the plurality of first laminations being thinner than the plurality of second laminations.

9. 2. The stator segment (100) of claim 1, wherein the stator segment (100) includes a plurality of teeth (120) attached to a base (110), the teeth (120) including a stator winding (130) around each of the teeth, the stator segment (100) further including a resilient element (140) disposed between each of the stator windings (130) and the base (110).

10. 1. A generator comprising a stator, a rotor and an air gap disposed radially between the stator and the rotor, the stator comprising: A stator rim (200); A plurality of stator segments (100) according to any one of claims 1 to 9; Including, A generator, comprising a stator segment (100) attached to a stator rim (200).

11. The generator of claim 10, wherein the generator is a direct drive wind turbine generator.

12. The generator of claim 10, wherein the generator is a permanent magnet generator.

13. A method (700) for assembling a stator segment (100), comprising the steps of: providing teeth (120) extending between a first end (121) and a second end (122); Providing a base (110) for mounting teeth (120); Arranging the stator windings (130) around the teeth (120); disposing one or more resilient elements (140) on the base (110) and / or the stator windings; - joining first ends (121) of the teeth, at least in part, by one or more resilient elements (140) to a base (110) carrying a stator winding (130); and attaching the teeth to the base (110) at a first end (121) of the teeth.

14. 14. The method (700) of claim 13, wherein the teeth (120) include a first sidewall and a second sidewall that include a protrusion (125), and joining the first ends (121) of the teeth to the base (110) includes holding the stator windings (130) between the protrusion (125) and one or more resilient elements (140).

15. The method (700) of claim 13 or 14, further comprising the step of attaching the stator segments to a rim of a stator of an electric machine.

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