Stator for wind turbine generator, generator and wind turbine

Abstract

The invention relates to a stator for a wind turbine generator, comprising a plurality of phase windings (4) of at least two phases (U, V, W), said phase windings (4) being arranged in a plurality of winding segments (5), in which each segment (5) has at least one output terminal (6, 7, 8) per phase (U, V, W), to which the respective phase winding (4) is connected, and said output terminals (6, 7, 8) are connected to a bus structure (18), characterized in that the phase windings (4) are arranged in the plurality of winding segments (5). Each output terminal (6, 7, 8) comprises a holder (11) attached to the stator structure (2) and a strip-shaped or box-shaped or plate-shaped connection terminal (14) connected to the holder (11) by at least one insulating element (13), where the connection terminal (14) comprises a connection means for connecting the holder (11) to the stator structure (2). According to the invention, flexible winding connection cables (9) connecting the respective phase windings (4) to the connection terminals (14) are connected to the connection means, in which the holders (11) have different heights for arranging the connection terminals (14) in different planes.

Description

Technical Field

[0001] The invention relates to a stator for a wind turbine generator, the stator comprising several phase windings of at least two phases, the phase windings being arranged in several winding segments, wherein each segment has at least one output terminal per phase, to which the respective phase winding is connected, and the output terminal being connected to a busbar structure. Background Art

[0002] The stator for a wind turbine generator typically includes a number of phase windings assigned to at least two, typically three, phases, commonly referred to as U, V, and W phases. The windings are arranged around the circumference of the stator. In direct-drive external rotor generators, the stator is positioned within the rotor, with the windings arranged at the outer circumference of the stator. The windings are typically arranged into several winding segments, each segment having at least one output terminal per phase. Each segment may have only one output terminal per phase, or may have several output terminals per phase. In known generators, these output terminals are implemented using busbars, which have a curved design and are arranged around the circumference of the stator. These busbars are produced using an extensive rolling process to achieve the required curved form. For example, if a three-phase generator is implemented, a total of six busbars are required to implement the output terminals for the three phases. These elongated, curved busbars are secured to a specific support member fixed to the generator structure. Within this support member, all busbars implementing the corresponding output terminals are secured together. Since the busbar is arc-shaped and extends around the perimeter, several such supports are required in order to secure the busbar along its length.The busbars are arranged in a stack with one busbar above the other, separated by insulating means.

[0003] The output terminals of these segments, or busbars, are further connected to a busbar structure that is further arranged inside the winding and output terminal arrangement and typically extends around approximately one-quarter of the circular stator. The output terminals are connected via additional connectors, also typically in the form of strips. Each phase of the output terminal is connected to a corresponding phase distribution busbar.

[0004] The busbars that make up the output terminals are typically impregnated using vacuum pressure impregnation after they are installed in the stator structure. In the event of a busbar failure, phase functionality is lost, which results in the complete or partial loss of that particular segment or phase. Because the busbars are arranged in a stack and impregnated, any fault in this area is extremely difficult to repair, as the generator must be completely shut down and partially disassembled by removing the busbars in order to repair the fault. This is very complex and expensive. Summary of the Invention

[0005] An object of the present invention is to provide a stator with a simplified design of the output terminals.

[0006] To achieve this object, the stator as described above is characterized in that each output terminal comprises a holder attached to the stator structure and a strip-shaped, box-shaped or plate-shaped connecting terminal connected to the holder via at least one insulating element, wherein the connecting terminal comprises a connecting device to which a flexible winding connection cable connecting the corresponding phase winding to the connecting terminal is connected, wherein the holder has different heights in order to arrange the connecting terminals in different planes.

[0007] The stator of the present invention has a completely new design of its output terminals and their connection to the windings. Each output terminal associated with a specific phase is a separate arrangement, and the output terminals assigned to a specific phase are not interconnected because no busbar is used to implement such output terminals. Instead, each output terminal comprises a holder, which is attached to the stator structure. It also comprises a connection terminal having a strip-like or plate-like form or design, which is connected to the holder by at least one insulating element for electrically isolating the connection terminal from the holder or the corresponding stator structure. The windings assigned to the corresponding phases are connected to the corresponding connection devices provided at the connection terminals by means of flexible winding connection cables. The use of these flexible winding connection cables allows the corresponding windings to be guided to the corresponding local connection terminals to which they are connected, making it easy to connect all the corresponding windings to the local small connection terminals of the phase distribution output terminals.

[0008] The output terminals assigned to two or three respective phases are further designed so that the holders have different heights, so that the connection terminals are ultimately arranged in different planes or different height levels. This allows for simple connection to a busbar structure that constitutes a quadrant busbar, which, as mentioned, extends around a portion of the circumference and can be easily arranged at different heights or levels of the connection terminals, thereby allowing for simple connection.

[0009] The stator of the present invention thus presents a new flexible phase connection design, as it no longer uses any busbars, including rolled and curved busbars that extend partially along the circumference of the respective segments. Instead, only local output terminals are required, consisting of simple retainers of a specific height, insulating elements, and connection terminals to provide the respective output terminals associated with the respective phases. Consequently, no specific busbar arrangement or stack is required to implement the output terminals, which offers significant advantages. Since no busbars are used to implement the output terminals, failures due to busbar failures are unlikely. Furthermore, since no such busbar arrangement is used, significantly more space is available, simplifying any maintenance work without having to dismantle the generator or, accordingly, shut down the turbine, or with significantly reduced downtime. Furthermore, the open space allows for better cooling, as cooling air can flow freely through this area. By eliminating the use of busbars, which are typically made of copper, costs can be significantly reduced, along with the overall weight. As mentioned, the respective output terminals, simplified in design, are merely locally arranged terminals and can therefore be placed at any suitable location within the segment. Connection of the respective windings via winding connection cables allows for simple connection of the respective windings regardless of where the respective output terminals are located. Furthermore, the height of the output terminals can be easily adjusted by adjusting the height of the holder, making the output terminals adaptable and scalable to various sizes, speeds, topologies, and / or applications, or corresponding stator sizes.

[0010] As mentioned, the output terminals are only partially arranged and include strip- or plate-shaped connecting terminals. These connecting terminals have a longitudinal axis that is preferably arranged at an angle of 45-135°, in particular 70-110°, relative to the central axis of the cylindrical stator and is preferably arranged radially. Thus, each longitudinal connecting terminal is arranged radially or nearly radially so that, in the case of a direct-drive generator, it extends from the windings arranged on the outside of the stator to the interior of the stator where the busbar structure is located. This arrangement of the connecting terminals allows for simplified routing of the winding connection cables to the corresponding connection means of the connecting terminals and further bridges the distance to the busbar structure.

[0011] As mentioned, the design of the output terminals is simplified, as they are only local, phase-specific terminals. One of the central elements of each output terminal is a retainer, which, as mentioned, is adapted in position and height to the height required by the busbar structure to which the terminal is to be connected. Such a retainer can be a U-shaped metal bracket. This simple steel bracket can be provided with corresponding attachment flanges on the sides for simply attaching or screwing the retainer to the stator structure. The steel bracket is a very simple mechanical mounting element, thus simplifying the design and reducing costs.

[0012] As mentioned, the connection terminals are connected to the holder via at least one insulating element, which can be made, for example, of ceramic or porcelain, or any other suitable material that provides the required electrical insulation properties. For example, the connection terminals can be attached directly to the insulating element via corresponding fixing screws. Alternatively, a carrier plate can be arranged on the at least one insulating element, to which the connection terminals are attached (e.g., screwed).

[0013] The connection terminals are preferably made of copper, so that corresponding copper strips or copper plates are used. These strips or plates are provided with corresponding connection means, such as threaded holes or through-holes, which are suitable for receiving corresponding screw connections. The use of copper terminals allows even higher voltage current densities to be conducted through the output terminals.

[0014] According to another embodiment, the connecting terminal comprises a busbar connecting device for connecting the corresponding connecting terminal to the corresponding busbar of the busbar structure, wherein the busbar connecting device is arranged at the radial inner side or inner end of the connecting terminal. As mentioned, each connecting terminal needs to be connected to a corresponding busbar of the busbar structure, which busbar is associated with the corresponding phase. The connecting terminal is designed to enable a simplified connection. In order to solve this problem, the connecting terminal comprises a corresponding busbar connecting device arranged at the radial inner side or inner end of the strip-shaped or plate-shaped connecting terminal. As mentioned, at the direct-drive generator, the busbar structure is arranged at the inner periphery of the stator structure. The corresponding busbar connecting devices are arranged at the radial inner side or inner end of the connecting terminal, and they are accurately positioned in the path along which the busbars of the busbar structure extend, so that a simple connection is possible.

[0015] As mentioned, output terminals are specifically associated with a particular phase. They are separate terminals with no interconnection. They can be placed anywhere along the perimeter of the corresponding segment. Preferably, the output terminals are arranged adjacent to each other, creating a terminal arrangement point or box where all output terminals are located (e.g., two output terminals in the case of two phases, three output terminals in the case of three phases). This is advantageous for maintenance purposes, as all corresponding connections are located at a single location.

[0016] Although the stator may be designed to have only two phases, the stator of the present invention preferably has a multi-phase winding, such as three-phase or six-phase, or multiple systems of multiple phases, such as two systems each having three phases.

[0017] In addition to the stator, the present invention also relates to a generator comprising a rotor and a stator as described above.

[0018] The generator is preferably a direct drive outer rotor generator for a direct drive wind turbine.Therefore, the stator is arranged inside the rotor.

[0019] Finally, the invention also relates to a wind turbine comprising such a generator. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. However, the accompanying drawings are only schematic diagrams designed for illustrative purposes only and do not limit the present invention. The accompanying drawings show: Figure 1 is a principal illustration in perspective form of a portion of a stator of the present invention, Figure 2 It has a busbar structure Figure 1 A main illustration of a portion of a stator of the present invention, Figure 3 It is the main diagram of three different output terminals. Figure 4 is a main illustration of a portion of the structure of the invention comprising a carrier board with three output terminals, Figure 5 is a main diagram of another embodiment of the output terminal, and Figure 6 is a principal illustration of a wind turbine according to the invention having a generator according to the invention. DETAILED DESCRIPTION

[0021] Figure 1 The main diagram shows a portion of a stator 1 according to the invention, which has a stator structure 2 comprising a plurality of metallic stator elements 3 to which a plurality of windings 4 assigned to three different phases are attached. The general arrangement of such a stator 1 is known and is suitable for direct-drive wind turbine generators, which additionally comprise a rotor surrounding the inner stator 1.

[0022] The phase winding 4 is preferably arranged into several winding segments 5, wherein Figure 1 A segment is shown in FIG. The phase winding 4 is associated with three different phases U, V and W, wherein for each phase U, V and W, a separate output terminal 6, 7 and 8 is provided. Output terminal 6 is associated with phase U, output terminal 7 is associated with phase V, and output terminal 8 is associated with phase W. The respective phase winding 4, which is also associated with the respective phase U, V and W, is connected to the respective output terminals 6, 7 and 8 by means of a flexible winding connection cable 9, as shown. Figure 1 As shown in . The phase windings 4 associated with the U phase are all connected to the output terminal 6 using corresponding connecting cables 9, the phase windings 4 associated with the V phase are all connected to the output terminal 7 using corresponding connecting cables 9, and the phase windings 4 associated with the W phase are all connected to the output terminal 8 using corresponding connecting cables 9. All of these connections are achieved by corresponding screw connections 10, as shown in Figure 1These screw connections 10 are realized by means of respective screws connected to respective output terminals, which output terminals comprise a plurality of connection means for receiving the respective screw connections 10 .

[0023] Each output terminal 6, 7 and 8 comprises a holder 11 realized in the form of a U-shaped metal bracket, which is attached to the stator structure 2 by means of corresponding screw connections 12. At least one insulating element 13 made of an electrically insulating material, such as ceramic, is attached to the bracket-like holder 11. Attached to this insulating element 13 is a strip-shaped connecting terminal 14, which is made of copper and extends almost radially to the center axis of the stator 1, such as Figure 1 The strip-shaped connecting terminal 14 is provided with a corresponding connecting device for receiving the screw connection 10, which is in the form of a threaded hole or a through hole, as shown in FIG. Figure 1 All output terminals 6, 7 and 8 have the same design and differ only in the corresponding dimensions of the holder 11, as will be combined with Figure 3 Descriptive.

[0024] Each connecting terminal 14 comprises a busbar connecting device 15 for connecting the corresponding connecting terminal 14 to a corresponding busbar of a busbar structure, an example of which is shown in FIG. Figure 2 This connection is also achieved by means of corresponding screw connections 16.

[0025] Figure 2 A quarter circle 17 of the stator 1 is shown, which comprises several segments 5. Figure 1 As explained, each segment 5 comprises a certain number of phase windings 4 associated with the three phases U, V and W, as explained. For illustration purposes, Figure 2 These phase windings 4 are not shown.

[0026] Figure 2 A busbar structure 18 is shown, comprising busbar sections 19 associated with respective segments 5. Each busbar section comprises three individual busbars in the form of elongated copper strips, which are stacked on top of each other and are therefore arranged at different heights. Figure 2 As shown, the elongated busbar stack of the busbar segments 19 extends at the inner periphery of the stator 1 close to the corresponding segment 5. One busbar of each busbar segment 19 is connected to one of the output terminals 6, 7 and 8 by means of a corresponding screw connection 16, respectively to the corresponding connection terminal 14 and its busbar connection device 15, as shown for Figure 1As explained above, each busbar section includes three busbars. One busbar is associated with one of phases U, V, and W. Therefore, the respective phases U, V, and W from the phase winding 4 are ultimately connected to the corresponding busbar of the busbar section 19. As shown, the busbar sections 19 are interconnected, meaning that the busbars of the busbar section 19 associated with phase U are all interconnected, and the same is true for the busbars associated with phases V and W.

[0027] As mentioned, the busbars of the busbar section 19 are stacked, so they are arranged at different heights or planes. As mentioned, the holders 11 also have different heights, so the connection terminals 14 of the output terminals 6, 7 and 8 are arranged at different heights, which correspond to the heights or corresponding levels of the busbars of the busbar section 19, making it easier to connect the busbars to the output terminals 6, 7, 8.

[0028] from Figure 1 It is obvious that all phase-related output terminals 6, 7 and 8 are only local devices, which are connected to the phase winding 4 via corresponding flexible connecting cables 9. They do not comprise any type of elongated and curved busbar stack as in the prior art, but only comprise corresponding holders 11 with insulating elements 13 and connecting terminals 14, which preferably extend in radial direction and allow firstly a simple connection of the corresponding phase winding and secondly a simple connection of the corresponding busbar of the associated busbar section 19. Figure 1 It is apparent that, since the three output terminals 6, 7, and 8 are locally concentrated at one location, any maintenance work is simplified, as all connection points are accessible from one location. Furthermore, much of the free space previously used by the corresponding busbars can now be used for cooling purposes, as air can easily circulate through this open space. Furthermore, since the output terminals are not implemented using expensive and heavy full busbars, any maintenance work related to the windings 4, etc., is also simplified, further reducing weight and costs.

[0029] Figure 3 The main diagram shows three output terminals 6, 7 and 8 associated with the three phases U, V and W as explained above. Each output terminal 6, 7 and 8 comprises a holder 11 realized in the form of a metal bracket 20 having a terminal flange 21 bent inwards or outwards and adapted to receive a corresponding screw connection 12, as already explained. The bracket 20 is preferably made of steel. Figure 3 As can be clearly seen, the brackets 20 have different heights: the bracket 11 of the output terminal 6 is the lowest, the bracket 20 of the output terminal 7 is in the middle, and the bracket 20 of the output terminal 8 is the highest.

[0030] A respective insulating element 13 is attached to each support 20, wherein in this embodiment two such insulating elements 13 are used for each output terminal 6, 7 and 8. They are attached to the support 20 by means of respective screw connections 22. Finally, the respective connecting terminal 14 is attached to the insulating element 13 by means of respective screw connections 23, as shown in FIG. Figure 3 Obviously, since the insulating elements 13 all have the same length, the connecting terminals 14 are at different heights or corresponding levels, which correspond to the different heights of the brackets 20. As explained, these different heights or levels correspond to the heights or corresponding levels of the different busbars of the busbar section 19.

[0031] Figure 4 A portion of a stator 1 is shown, wherein only the stator structure 2 and the metallic stator elements 3 are shown, but the phase windings 4 are not shown. Instead, three output terminals 6, 7 and 8 are shown. Their design is similar to that for Figure 4 The explained design corresponds. Figure 4 An additional carrier plate 24 is shown attached to the respective insulating element 13, which carrier plate 24 ultimately receives the connecting terminal 14. When the connecting terminal 14 can be attached directly to the insulating element 13, the carrier plate 24 can be omitted.

[0032] Figure 5 An embodiment of the connecting terminal 14 is shown, which has Figure 1 Another example of a different shape of connection terminal is shown in , where the connection terminal 14 is a longitudinal copper strip with a busbar connection device 15 at the inner end. Figure 5 The connecting terminal 14 shown in FIG is also an elongated copper strip, but the inner end 25 is slightly bent so that the busbar connecting device 15 is also as shown in FIG. Figure 5 Slightly curved as shown.

[0033] at last, Figure 6 A wind turbine 26 according to the present invention is shown, having a tower 27 to which a nacelle 28 is mounted. Also shown is a generator 29 according to the present invention, comprising an inner stator 1 according to the present invention and an outer rotor 30. Rotor 30 is directly connected to a hub 31, to which several rotor blades 32 are attached. When wind blows, it interacts with rotor blades 32, causing hub 31 to rotate, thereby causing rotor 30 to rotate relative to the fixed stator 1, thereby causing the generator to generate electrical power.

[0034] Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the disclosed examples, and a skilled person will be able to derive other variations from the disclosed examples without departing from the scope of the present invention.

[0035] Regardless of how the grammatical term is used, the term includes individuals with male, female, or other identities.

Claims

1. A stator for a wind turbine generator, comprising a plurality of phase windings (4) of at least two phases (U, V, W), said phase windings (4) being arranged into a plurality of winding segments (5), wherein: Each segment (5) has at least one output terminal (6, 7, 8) per phase (U, V, W), to which the corresponding phase winding (4) is connected, and the output terminals (6, 7, 8) are connected to a busbar structure (18), characterized in that each output terminal (6, 7, 8) comprises a holder (11) attached to the stator structure (2) and a strip-shaped, box-shaped or plate-shaped connecting terminal (14) connected to the holder (11) via at least one insulating element (13), wherein the connecting terminal (14) comprises a connecting device to which a flexible winding connection cable (9) connecting the corresponding phase winding (4) to the connecting terminal (14) is connected, wherein the holder (11) has different heights in order to arrange the connecting terminals (14) in different planes.

2. The stator according to claim 1, characterized in that The connecting terminals (6, 7, 8) have a longitudinal axis which is arranged at an angle of 45-135°, more particularly 70-110°, to the central axis of the cylindrical stator (1) and is preferably arranged in a radial direction.

3. The stator according to claim 1 or 2, characterized in that: The retainer (11) is a U-shaped metal bracket (20).

4. A stator according to any one of the preceding claims, characterized in that A carrier plate (24) is arranged on the insulating element (13), and the connecting terminals (14) are attached to the carrier plate (24).

5. A stator according to any one of the preceding claims, characterized in that The connecting terminal (14) is a copper bar or a copper plate.

6. A stator according to any one of the preceding claims, characterized in that The connecting terminal (14) comprises a busbar connecting device (15) for connecting the corresponding connecting terminal (14) to the corresponding busbar of the busbar structure (18), wherein the busbar connecting device (15) is arranged at the radial inner side or inner end of the connecting terminal (14).

7. A stator according to any one of the preceding claims, characterized in that The output terminals (6, 7, 8) of different phases (U, V, W) are arranged adjacent to each other.

8. A stator according to any one of the preceding claims, characterised in that A three-phase (U, V, W), six-phase or multi-phase multi-system phase winding (4) is provided.

9. Generator comprising a rotor (30) and a stator (1) according to any one of the preceding claims.

10. The generator according to claim 9, characterized in that The stator (1) is arranged inside the rotor (30).

11. A wind turbine comprising a generator (29) according to claim 9 or 10.

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