WO2015007338A1

WO2015007338A1 - A wind power generation assembly

Info

Publication number: WO2015007338A1
Application number: PCT/EP2013/065294
Authority: WO
Inventors: Jahirul Islam; Wenliang Chen; Yujing Liu
Original assignee: Abb Technology Ltd
Priority date: 2013-07-19
Filing date: 2013-07-19
Publication date: 2015-01-22

Abstract

A wind power generation assembly (1) comprising a vertical support structure (2), a nacelle (3) mounted on the support structure, a wind rotor (5) mounted to the nacelle and connected to a horizontal input shaft (11) and driving the input shaft to rotate about a horizontal rotation axis A. Further, it comprises a double stator electric generator (13) comprising a generator rotor (17), and a connection arrangement (19) for connecting the input shaft (11) to the generator rotor (17), which connection arrangement comprises a gearing assembly (21) for transferring the rotary motion of the input shaft to a rotary motion of the generator rotor. The generator is arranged such that the generator rotor (17) is rotatable about a vertical rotation axis B.

Description

A WIND POWER GENERATION ASSEMBLY

TECHNICAL FIELD

The present invention relates to a wind power generation assembly comprising a support structure such as a vertical support tower, a nacelle mounted on the support structure, a wind rotor mounted to the nacelle, and an electric generator. The wind rotor drives an input shaft in rotation and the input shaft is connected to the generator rotor such that the rotation of the input shaft also rotates the generator rotor.

Wind power generators, or wind turbines as they are also often called, are e.g. used on land, but they may also be used at sea, on an oil platform etc.

BACKGROUND ART

In the wind turbine industry, there is a development towards higher power ratings in order to continue to push down the cost of energy. The conventional approaches to increase power ratings are typically to increase the diameter or axial length of the generator. In the case of direct drive wind power, it is preferred to increase the diameter, from a purely generator electromagnetic perspective. However, the large diameter of the direct drive generator involves great challenges when it comes to transportation and assembly, both at the factory and the installation sites.

One known alternative is to use a double stator generator which has the advantage of making it possible to increase the power without increasing the diameter or axial length of the generator. This structure can utilize the large hollow space inside the turbine. However, the double stator generator has a cup type rotor support which has limitations when it comes to mechanical robustness.

Examples of prior art wind turbines of the double stator type are described in

US 2013/0161958 and US 5783893. According to US 2013/0161958 is disclosed a wind power generator of the horizontal type, having a permanent magnet direct-driven generator with a double stator supported on a fixed shaft. The rotor is attached to a hollow rotating shaft mounted on the fixed shaft. In US 5783893 is disclosed an electric machine, e.g. a generator, having a double stator attached to the housing and a cup shaped rotor attached to a shaft. SUMMARY OF THE INVENTION

One object of the present inventions is to provide a wind power generation assembly with high power capacity that is less cumbersome to handle, both at the factory and at the installation site, and which also displays good mechanical strength.

In order to attain this object, the present invention proposes a wind power generation assembly comprising a vertical support structure, a nacelle mounted on the support structure, a wind rotor mounted to the nacelle and connected to a horizontal input shaft and driving the input shaft to rotate about a horizontal rotation axis, a double stator electric generator comprising a generator rotor, a connection

arrangement for connecting the input shaft to the generator rotor, which connection arrangement comprises a gearing assembly for transferring the rotary motion of the input shaft to a rotary motion of the generator rotor, characterised in that the generator is arranged such that the generator rotor is rotatable about a vertical rotation axis.

Through this invention is offered the advantage that the generator is located vertically and therefore the nacelle can be made smaller and more compact. The generator does not even have to be located in the nacelle, but can be located in the vertical support structure, in the upper part of the support structure close to the nacelle or in the lower part of the support structure, or even at ground level in a separate machine room. As a result of the smaller and more compact nacelle, the handling of the wind power generation assembly and its components will be made easier and less cumbersome, both in the factory, during transportation and on the installation site. This will entail reduced costs, improved safety etc.

According to one embodiment, the gearing assembly may comprise a first gearing device for transferring a rotary motion of the input shaft about the horizontal rotation axis to a rotary motion of the generator rotor about the vertical rotation axis.

According to one embodiment, the first gearing device may comprise a direct drive gear arrangement. This provides a very compact solution.

Further, the gearing assembly may also comprise a second gearing device comprising a gearbox of at least one stage.

Alternatively, according to another embodiment, the first gearing device may comprise a gearbox of at least one stage. This has the advantage of providing both the angular rotary transmission from horizontal to vertical axis and the gearbox function in one device, e.g. an angular gearbox. According to a further embodiment, the first gearing device may comprise a first gearwheel connected to the input shaft and a second gearwheel that comprises an end surface of the generator rotor, which end surface is designed as a gearwheel. This is suitable for a direct drive transmission.

According to a further embodiment, the generator may comprise a central rotor shaft, and a rotor end element having a first side where it is connected to the central rotor shaft and a second opposite side where it is connected to the generator rotor, such that the central rotor shaft further is connected to the gearing assembly, and the gearing assembly may be adapted to transfer a rotary motion from the input shaft to the central rotor shaft, and thereby to the generator rotor, via the rotor end element. One advantage with this is that the generator may be located at some distance from the input shaft. For example, the generator may be located in the support structure, underneath the nacelle, further down in the support structure and even on the ground in the support structure. The nacelle can therefore be made smaller, more compact and easier to handle.

According to a further embodiment, the generator may be designed as not having a central shaft located internally of the first inner stator; in other words a shaft less generator. This is possible since the first gearing device may comprise a first gearwheel connected to the horizontal input shaft and a second gearwheel connected to or integrated with one end of the generator rotor. One advantage of this is less rotating parts and a lighter construction.

According to yet another embodiment, the generator may comprise a fixed generator shaft located internally of the first inner stator, and a rotor end element connected to the generator rotor may be supported on an end of the fixed generator shaft by means of a bearing arrangement. This will contribute to increased robustness of the generator design.

Alternatively, the generator may comprise a rotary generator shaft located internally of the first inner stator and connected to the rotor end element. This will also contribute to increased robustness of the generator.

In one embodiment, the generator may be located in the support structure.

This has the advantage of providing for a less heavy and more compact nacelle, since the nacelle does not have to house the generator.

In another embodiment, the generator may be located at ground level. By ground level is meant the lowermost part of the support structure, where the support structure itself is supported, irrespective of if it is at land or at sea or on e.g. an oil platform.

In yet another embodiment, the generator may be located in the nacelle. The advantage of this, as compared to prior art, is that the nacelle could be made more compact with a horizontal generator.

According to a further aspect, the generator may be a synchronous permanent magnet generator.

According to another aspect, the nacelle may be rotatably mounted on the support structure. As a result, the nacelle can then be moved depending on the preferred wind direction in order to obtain optimum power output. This aspect is applicable irrespective of if the generator is located in the nacelle or in the support structure.

In general, the inventive wind power generation assembly provides for high power density with a more compact structure that may also be modularised and segmented for easy transportation and installation. The inventive assembly is adapted for production of high power in the range of 500 kW and higher, and even 3MW and higher.

Further features and advantages of the present invention will become apparent from the following detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail, with reference to the appended schematic drawings, illustrating different aspects and embodiments of the invention, given as examples only, and in which:

Fig. 1 is a schematic partial side view, in cross section, of a first embodiment of a wind power generation assembly according to the present invention,

Fig. 2 is a schematic top view of details of the wind power generation assembly of Fig. 1 ,

Fig. 3 is a schematic partial side view, in cross section, of a second

embodiment of a wind power generation assembly, according to the present invention,

Fig. 4 is a schematic partial side view, in cross section, of a third embodiment of a wind power generation assembly, according to the present invention,

Fig. 5 is a schematic partial side view, in cross section, of a fourth embodiment of a wind power generation assembly, according to the present invention, Fig. 6 is a schematic partial side view, in cross section, of a fifth embodiment of a wind power generation assembly, according to the present invention,

Fig. 7 is a schematic partial side view, in cross section, of a sixth embodiment of a wind power generation assembly, according to the present invention,

Fig. 8 is a schematic view, illustrating schematically an application of a wind power generation assembly according to the first or alternatively the second

embodiment, according to the present invention,

Fig. 9 is a schematic view, illustrating schematically an application of a wind power generation assembly according to the third, fourth, fifth or alternatively the sixth embodiment, according to the present invention, and

Fig. 10 is a schematic view, illustrating schematically another application of a wind power generation assembly according to the third, fourth, fifth or alternatively the sixth embodiment, according to the present invention.

In the drawings, the same elements or corresponding elements in the different embodiments have been given the same reference number.

DETAILED DESCRIPTION

In Figs. 1 and 3-10 is schematically illustrated a wind power generation assembly 1 comprising a nacelle 3 with a wind rotor 5 mounted thereto, in accordance with the present invention. The wind rotor comprises a wind rotor hub 7 provided with wind rotor blades 9 (not shown in Figs. 1 , 3-7). The wind rotor is connected to a rotatable input shaft 1 1 of the wind power generation assembly, which is driven to rotate about a horizontal rotation axis A by the rotor blades when they are rotated by the wind. The wind power generation assembly 1 further comprises a double stator electric generator 13, e.g. of the synchronous, permanent magnet type. The electric generator 13 comprises a first inner stator 15, a second outer stator 16, and a generator rotor 17 arranged to rotate around a vertical axis of rotation B. Further, it comprises a connection arrangement 19 for connecting the input shaft 1 1 to the generator rotor 17. The connection arrangement 19 comprises a gearing assembly 21 for transferring the rotary motion of the input shaft 1 1 around the horizontal axis A to a rotary motion of the generator rotor 17 around the vertical axis B. Thus the input shaft 1 1 and the generator rotor 17 are placed at a right angle relative each other. The first and second stators are fixed in a generator support structure, e.g. generator housing, in a suitable manner as is generally known in the art. There are also provided bearing arrangements as necessary, e.g. for the generator rotor 17.

In Fig. 1 is shown a first embodiment of the wind power generation assembly 1 . The electric generator 13 is a shaft less generator, in the sense that the generator has no central shaft located internally of the inner stator 15. The gearing assembly 21 comprises a first gearing device for example angular gears of a bevel gearing type, including one gear wheel connected to the input shaft which cooperates with one gear wheel connected to the generator rotor, and which gear wheels are at a right angle relative each other, in order transfer the rotary motion of the input shaft to a rotary motion of the generator rotor. This may be a direct drive gearing 23. One example is illustrated in Fig. 2. This direct drive gearing comprises a first gearwheel 24 connected to the input shaft 1 1 , and a second gearwheel 25 connected to the upper end surface of the generator rotor 17. The second gearwheel 25 may even be integrated in the upper end surface of the generator rotor 17.

In addition to the first gearing device, direct drive or not, the gearing assembly

21 may comprise a second gearing device comprising a gearbox that can be a one, two or multi-stage gearbox. As an alternative, the gearbox function may also be included in the first gearing device by using an angular gearbox including gear wheels at right angles to each other.

There may also be provided a rotor end element 27 on top of the generator rotor 17, internally of the second gear wheel 25, as schematically illustrated in Figs. 1 and 3. This rotor end element has a stabilising function and provides increased robustness of the structure. It would usually have the general shape of a circular plate, which may be a solid plate or a plate with openings. In Fig. 2, the end element is not shown, in order to also be able to show the inner stator 15. The end element may be supported on the stator support structure by a bearing arrangement. Alternatively, the gearing of the second gear wheel 25 may be integrated in the end element 27 covering the generator rotor end.

In Fig. 3 is shown a second embodiment of the inventive wind power generation assembly. In this embodiment, the electric generator has a fixed generator shaft 29, internally of the inner stator. The end element 27 is supported by this shaft via a bearing arrangement 31 . This shaft has a stabilising function and by using the bearing on top of the shaft for support of the end element 27 connected to the generator rotor 17, the mechanical strength of the generator is improved. Otherwise, the embodiment in fig. 3 has the same elements as the first embodiment, including the possibility of the different solutions with regard to the gearing assembly 21 .

Fig. 4 illustrates a third possible embodiment. In this embodiment, the generator comprises a central rotary rotor shaft 33 of which one end is connected to a rotor end element 27, on one side of the end element. Also in case, the end element 27 would usually have the general shape of a circular plate, which may be a solid plate or a plate with openings. On the opposite side of the end element, the generator rotor 17 is connected to the end element. Thus, the generator rotor 17 is connected to the central rotor shaft 33, via the end element 27. The central rotor shaft 33 is further connected to the gearing assembly 21 , at its other end, and consequently connects the generator rotor 17 to the gearing assembly 21 , via the end element 27. Thus the gearing assembly 21 is centrally located in relation to the generator rotor and the end element 27 is connected to the upper end of the generator rotor, i.e. the end facing toward the input shaft 1 1 . The gearing assembly 21 can be made according to any one of the previously disclosed solutions. The gearing assembly 21 transfers a rotary motion of the input shaft 1 1 around the horizontal axis A to a rotary motion of the central rotary rotor shaft 33 around the vertical axis B and thereby rotates the generator rotor 17 around the vertical axis B. In the embodiment illustrated in Fig. 4, the end element 27 is supported on a fixed generator shaft 29, by means of a bearing 31 , in a manner corresponding to the second embodiment in Fig. 3.

Alternatively, the generator shaft may be a rotary generator shaft 39 that will rotate together with the central rotary rotor shaft 33, as illustrated with the fourth embodiment in Fig. 5.

As another alternative, there is no generator shaft, in analogy with the first embodiment of Fig. 1 . This is illustrated by the fifth embodiment in Fig. 6.

The embodiments shown in Figs. 4, 5 and 6 are particularly suitable for installation of the generator in the support structure 2 of the wind power generation assembly, such as the tower, instead of in the nacelle 3. In the sixth embodiment, schematically illustrated in Fig. 7, the nacelle is separated from the support structure 2 in such a manner that the nacelle may be rotated around the vertical axis B in order to find an optimal position in relation to the wind direction. The gearing assembly 21 will consequently comprise additional gearings to enable such movement and further there is provided a motor (not shown) that drives the nacelle in rotation. Additional equipment is also installed that will determine the said position in relation to the wind direction.

Figs. 8-10 are schematic views, illustrating different applications of the wind power generation assembly according o the invention. In Fig. 8 is shown an application where the electric generator is located in the nacelle 3 of the wind generation assembly 1 . In this case, the electric generator is preferably designed in accordance with the first or second embodiments, as shown in Figs. 1 and 3. However, also the embodiments shown in Figs. 4-7 would be possible.

Fig. 9 shows a wind power generation assembly where the electric generator is located in the support structure 2, shown as a tower. For this application, it is suitable to use an electric generator design according to the third, fourth, fifth or sixth embodiment, as shown in Figs. 5-7. Optionally, the nacelle may be rotatable.

Finally, in fig . 10 is shown a wind power generation assembly where the electric generator is located at ground level 35, in the support structure. In this case, an electric generator design according to the third, fourth, fifth or sixth embodiment, as shown in Figs. 4-7, would also be used.

In addition to what is described above, the wind power generation assembly of the present inventions would naturally also be provided with converters, cooling equipment, cabling etc. and other equipment common to a wind power generation assembly, which is however not shown in the figures for simplicity reasons.

The present invention is not limited to the disclosed examples, but may be modified in many ways that would be apparent to the skilled person, within the scope of the appended claims.

Claims

PATENT CLAIMS

1 . A wind power generation assembly (1 ) comprising a vertical support structure (2), a nacelle (3) mounted on the support structure, a wind rotor (5) mounted to the nacelle and connected to a horizontal input shaft (1 1 ) and driving the input shaft to rotate about a horizontal rotation axis A, a double stator electric generator (13) comprising a generator rotor (17), a connection arrangement (19) for connecting the input shaft (1 1 ) to the generator rotor (17), which connection arrangement comprises a gearing assembly (21 ) for transferring the rotary motion of the input shaft to a rotary motion of the generator rotor, characterised in that the generator is arranged such that the generator rotor (17) is rotatable about a vertical rotation axis B.

2. A wind power generation assembly according to claim 1 , characterised in that the gearing assembly (21 ) comprises a first gearing device for transferring the rotary motion of the input shaft about the horizontal rotation axis A to a rotary motion of the generator rotor (17) about the vertical rotation axis B.

3. A wind power generation assembly according to claim 2, characterised in that the first gearing device comprises a direct drive gear arrangement (23).

4. A wind power generation assembly according to any one of claims 1 -3s,

characterized in that the gearing assembly (21 ) comprises a second gearing device comprising a gearbox of at least one stage.

5. A wind power generation assembly according to claim 1 or claim 2, characterised in that the first gearing device comprises a gearbox of at least one stage.

6. A wind power generator according to any one of claims 1 -5, characterised in that the first gearing device comprises a first gearwheel connected to the input shaft (1 1 ) and a second gearwheel (25) that comprises an end surface of the generator rotor (17), which end surface is designed as a gear wheel.

7. A wind power generation assembly according to any one of claims 1 -5,

characterized in that the generator (13) comprises a central rotor shaft (33), and a rotor end element (27) having a first side where it is connected to the central rotor shaft (33) and a second opposite side where it is connected to the generator rotor, that the central rotor shaft (33) further is connected to the gearing assembly (21 ), and in that the gearing assembly (21 ) is adapted to transfer a rotary motion from the input shaft (1 1 ) to the central rotor shaft (33), and thereby to the generator rotor (17), via the rotor end element (27).

8. A wind power generation assembly according to any one of the preceding claims, characterized in that the generator (13) does not have a central shaft located internally of the first inner stator.

9. A wind power generation assembly according to any one of claims 1 -7,

characterized in that the generator (13) comprises a fixed generator shaft (29) located internally of the first inner stator (15) and in that a rotor end element (27) connected to the generator rotor (17) is supported on an end of the fixed generator shaft by means of a bearing arrangement (31 ).

10. A wind power generation assembly according to claim 7, characterised in that the generator (13) comprises a rotary generator shaft (39) located internally of the first inner stator (15) and connected to the rotor end element (27).

1 1 . A wind power generator assembly according to any one of claims 1 -10,

characterized in that the generator (13) is located in the support structure (2).

12. A wind power generator assembly according to claim 1 1 , characterized in that the generator (13) is located at ground level.

13. A wind power generator assembly according to any one of claims 1 -10,

characterized in that the generator (13) is located in the nacelle (3).

14. A wind power generator assembly according to any one of the previous claims, characterized in that the generator (13) is a synchronous permanent magnet generator.

15. A wind power generator assembly according to any one of the previous claims, characterized in that the nacelle (3) is rotatably mounted on the support structure (2).