WO2011091476A1

WO2011091476A1 - Wind turbine

Info

Publication number: WO2011091476A1
Application number: PCT/AU2011/000088
Authority: WO
Inventors: Kim Xavier Wood; Arthur David Dewis
Original assignee: QUIET ENERGY SECURITIES Pty Ltd
Current assignee: QUIET ENERGY SECURITIES Pty Ltd
Priority date: 2010-01-29
Filing date: 2011-01-31
Publication date: 2011-08-04
Anticipated expiration: 2012-07-29

Abstract

A wind turbine is disclosed. The wind turbine comprises an assembly of an electricity generator and a rotor that is operatively coupled to the generator. The rotor forms a rear end of the assembly and has blades that extend outwardly and rearwardly when viewed in the wind direction.

Description

WIND TURBINE

The present invention relates to a wind turbine for converting the kinetic energy of wind into electrical energy .

The present invention also relates to an assembly of an electricity generator and a rotor operatively coupled to the generator for use in a wind turbine .

The present invention provides a wind turbine that comprises an assembly of an electricity generator and a rotor that is operatively coupled to the generator, the assembly being adapted to point into the wind, the rotor being rotatable about an axis that, in use, is coincident with the direction of wind that contacts the wind turbine, the rotor forming a rear end of the assembly and having blades that extend outwardly and rearwardly when viewed in the wind direction, and the blades being shaped to convert air flow against the blades into rotary movement of the rotor that drives the generator.

The electricity generator may be located forwardly of the rotor.

The generator/rotor assembly may comprise a housing for the generator.

The housing may be shaped to minimise resistance to air flow over the housing.

The housing may be located forwardly of the rotor.

The housing may be shaped to minimise resistance to air flow over the housing and disturbence to air flow to the rotor. For example, the housing may have a curved forward end and may taper inwardly from the forward end to a rearward end of the housing. The rotor blades may extend outwardly and rearwardly from the rotor axis .

The rotor may comprise a rotor body from which the blades extend that is operatively mounted to a generator shaft to rotate the shaft and thereby drive the generator.

The rotor body may be shaped to minimise resistance to air flow over the rotor body. The shape of the rotor body may be an extension of the shape of the housing so that there is a smooth

transition for air flow over the housing and the rotor body. An outer surface of the housing and/or an outer surface of the rotor body may be formed to promote

streamlined air flow and minimise turbulence and thereby improve performance. For example, the outer surface of the housing and/or the outer surface of the rotor body may be a dimpled surface .

The rotor blades may extend outwardly and rearwardly at an angle in a range of 30-60° to the axis of rotation of the rotor.

The rotor blades may have a uniform transverse cross- section along the length of the blades .

Each rotor blade may be curved from a leading end to a trailing end of the blade, as viewed from the wind direction .

Each rotor blade may comprise a first section that curves radially outwardly from the leading end of the blade and a second section that curves radially inwardly from the first section towards the rear end of the blade, as viewed from the wind direction. Consequently, in use, an inner surface and an outer surface of the blade are contacted by air flow.

The rotor blades may be fixed pitch blades or variable pitch blades .

The use of variable pitch blades makes it possible to optimise the blade angle for a given environmental condition. In addition, the use of variable pitch blades makes it possible to fail safe a generator/alternator from an over-speed state. More particularly, the purpose of variable pitch blades to:

(a) extract the maximum energy presently available in the wind by adjusting the blade pitch to its optimum angle for that wind speed, and (b) enable "feathering" of the blades should the

wind speed tend to force the wind turbine to exceed its safe operation rotational speed and thus maintain rotational speed within preset limits .

The variable pitch rotor blades may be adapted to wash-in or wash-out.

The wind turbine may comprise a sensing device to control the rotational speed of the rotor.

The sensing device may comprise any one or more of a sensor for:

(a) rotational speed,

(b) thermal operation, such as the temperature of the generator,

(c) wind velocity, and

(d) energy output of the generator.

The rotational speed sensor may be adapted to sense rotational speed of the rotor and adjust pitch angle to keep the rotational speed at a preset maximum.

The thermal operation sensor may be adapted to select a pitch angle that will extract maximum energy from the wind at any given wind speed and be limited only by the operating temperature of the windmill .

The wind velocity sensor may be adapted to compare and evaluate wind velocity and adjust pitch angle in response to a preset relationship between wind velocity and pitch angle.

The energy output sensor may be adapted to control pitch angle under "normal" operating conditions to extract maximum energy from the wind at any given wind speed.

The rotor may comprise a ring-shaped fairing that interconnects the outer ends of the blades and thereby stabilises the blades.

The wind turbine may comprise a tower or a pole or other type of upwardly extending structure that supports the generator/rotor assembly above the ground for rotation about a vertical axis of the support structure so that the assembly can rotate to point into the wind.

A lower section of the housing for the generator may be shaped to minimise resistance to air flow past an upper section of the support structure.

The present invention also provides an assembly of an electricity generator and a rotor that is operatively coupled to the generator for use in a wind turbine, the assembly being adapted to point into the wind in use of the assembly in the wind turbine, the rotor being

rotatable about an axis , the rotor forming a rear end of the assembly and having blades that extend outwardly and rearwardly from a forward end of the assembly and are shaped to convert air flow against the blades into rotary movement of the rotor that can drive the generator, the assembly comprising a housing for the generator and a rotor body that are shaped to minimise resistance to air flow over the rotor body.

The electricity generator and the generator housing may be located forwardly of the rotor.

The housing may be shaped to minimise resistance to air flow over the housing and disturbence to air flow to the rotor.

The rotor body may be an extension of the generator housing so that there is a smooth transition for air flow over the housing and the rotor body.

For example, the housing may have a curved forward end and may taper inwardly from the forward end to a rearward end of the housing.

The present invention provides a wind turbine that comprises an assembly of an electricity generator and a rotor that is operatively coupled to the generator, the assembly being adapted to point into the wind, the rotor being rotatable about an axis that, in use, is coincident with the direction of wind that contacts the wind turbine, the rotor having blades that are shaped to convert air flow against the blades into rotary movement of the rotor that drives the generator, the assembly comprising a housing for the generator and a rotor body that are shaped to minimise resistance to air flow over the rotor body, and the generator housing and/or the rotor body having outer surfaces that are formed to promote streamlined air flow and minimise turbulence and thereby improve

performance .

The outer surface of the housing and/or the outer surface of the rotor body may be a dimpled surface to promote streamlined air flow and minimise turbulence and thereby improve performance.

The rotor may form a rear end of the assembly and the blades may extend outwardly and rearwardly from a forward end of the assembly and are shaped to convert air flow against the blades into rotary movement of the rotor that drives the generator.

The electricity generator may be located forwardly of the rotor.

The present invention is described further by way of example only with reference to the accompanying drawings , of which :

Figure 1 is a side view in diagrammatic form of an electricity generator that forms part of a generator/rotor assembly and an upstanding support pole of one embodiment of a wind turbine in accordance with the present

invention ; Figure 2 is a further diagrammatic side view that shows further detail of the generator/rotor assembly of the wind turbine shown in Figure 1 and, more particularly, shows a generator housing and a rotor body of the assembly and the location of the generator shown in Figure 1 within the housing;

Figure 3 is an underside view in diagrammatic form of the generator/rotor assembly shown in Figure 2 and, more particularly, shows two of the blades of the rotor and the mounting location of the assembly to the support pole;

Figure 4 is a top view in diagrammatic form of the generator/rotor assembly shown in Figures 2 and 3 and, more particularly, shows an outer fairing of the rotor mounted to the rotor blades ;

Figure 5 is a cross-section along the line A-A in Figure 4 that shows a transverse profile of one of the rotor blades ;

Figure 6 is a side view in diagrammatic form of another, although not the only other, embodiment of a wind turbine in accordance with the present invention; and

Figure 7 is a series of cross-sections along the lines B-B, C-C, D-D, and E-E of Figure 6.

The wind turbine shown in Figures 1 to 5 comprises a generator/rotor assembly 3 that is mounted to an

upstanding pole 5 so that the assembly 3 is free to rotate about the vertical axis of the pole to point into the prevailing wind at any point in time .

Figures 1 to 4 are a series of diagrams that show the main components of the generator/rotor assembly 3. Figure 1 is a side view that shows the electricity generator 7 of the assembly 3. The generator 7 comprises (a) a generator body 9 that houses the main components of the generator and (b) a drive shaft 11. Figure 2 shows more detail of the assembly 3 and, in particular, shows a generator housing 13 and a rotor body 15 of the rotor of the

assembly and the location of the generator 7 within the housing 13. Figure 3 shows more detail of the assembly 3 and, in particular, shows two of a plurality of blades 17 of the rotor of the assembly and a mounting location 21 for mounting the assembly 3 to the support pole 5. Figure 4 shows more detail of the assembly 3 and, in particular, shows an outer fairing 19 of the rotor mounted to the rotor blades 17.

The generator/rotor assembly 3 and the pole 5 are constructed so that the assembly 3 can be mounted to an upper end of the pole 5 for rotation about a vertical axis of the pole. This makes it possible for the assembly 3 to rotate as required to align with the direction of wind. As will be evident for the following description, the construction of the assembly 3 enables the assembly 3 to self-align with the wind direction.

The rotor is operatively coupled to the drive shaft 11 of the generator 7 so that rotation of the rotor rotates the drive shaft 11 and the drive shaft 11 operates the generator and generates electricity. The arrangement is such that the generator 7 is positioned so that the drive shaft 11 is co-incident with the wind direction. The axis of the drive shaft 11 is therefore the axis of rotation for the rotor.

The generator housing 13 and the rotor body 15 are shaped to minimise resistance to air flow over the housing 13 and the rotor body 15. As can best be seen in Figures

2 to 4 , these components define a torpedo-shaped arrangement that has a curved forward end and tapers inwardly from the forward end to a rearward end, as viewed from the direction of wind towards the wind turbine , i.e. from the left to the right of the drawings. In addition, the outer surfaces of the housing 13 and the rotor body 15 are dimpled to promote streamlined air flow and minimise turbulence and thereby disturbence of air flow to the rotor blades 17 and thereby improve performance of the rotor. It can readily be appreciated that the present invention is not limited to torpedo-shaped arrangements for the generator housing 13 and the rotor body 15.

The rotor body 15 supports the rotor blades 17 to extend rearwardly and outwardly from the assembly 3, as viewed from the wind direction. Two blades 17 are shown in the drawings. However, it can readily be appreciated that the assembly may have any suitable number of blades 17. The rotor blades 17 extend outwardly and rearwardly at an angle of 45° to the axis of rotation of the rotor. The rotor blades 17 have a uniform transverse cross- section along the length of the blades. In addition, as can best be seen in Figure 4, each rotor blade 17 is curved from a leading end 27 to a trailing end 29 of the blade, as viewed from the wind direction. More

particularly, with further reference to Figure 4, each rotor blade 17 comprises a first section 31 that curves radially outwardly from the leading end 27 of the blade and a second section 33 that curves radially inwardly from the first section towards the rear end 29 of the blade, as viewed from the wind direction. Consequently, in use, an inner surface 35 and an outer surface 37 of each rotor blade 17 are contacted by air flow. The impact of the air flow against the surfaces 35, 37 is to cause controlled rotation of the rotor about the rotor axis and thereby drive the drive shaft 11 of the generator. The rotor blades 17 may be fixed or variable pitch blades . The use of variable pitch blades makes it possible to optimise the blade angle for a given

environmental condition. In addition, the use of variable pitch blades makes it possible to fail safe a

generator/alternator from an over-speed state. More particularly, the purpose of variable pitch blades to:

(a) extract the maximum energy available in the wind at any point in time by adjusting the blade pitch to its optimum angle for that wind speed, and

(b) enable "feathering" of the blades should the

The ring-shaped fairing 19 interconnects the outer ends of the rotor blades 17 and thereby stabilises the blades 17.

Figures 6 and 7 show another, although not the only other possible, embodiment of the wind turbine of the present invention. The basic construction of the wind turbine is the same as that shown in Figures 1 to 5. The main difference is that a lower section 37 of the

generator housing 13 is shaped as shown in the Figures to minimise resistance to air flow past an upper section of the pole 5.

The wind turbines described above in relation to the drawings have the following features .

• Aerodynamically stable. • Self weather-cocking design.

• The dimpled design of the housing and the rotor body

promote streamlined air flow and minimise turbulence and noise and thereby improve performance.

• Both sides of the blade profile are contacted by air flow and this feature of the design improves efficiency and power generation.

• The fairing stabilises the blade tips and provides an aerodynamic barrier that reduces vortices at the ends of the blades .

Many modifications may be made to the embodiments of the wind turbine of the present invention described above with reference to the drawings without departing from the spirit and scope of the invention.

By way of example, whilst present invention is not limited to the particular shapes of the components shown in the drawings , such as the shapes of the rotor blades 17, the generator housing 13, and the rotor body 15.

By way of further example, the present invention is not limited to the particular mounting of the assembly 3 to the pole 5 and to the use of poles per se. With regard to the latter point, the present invention extends to any structure that can support the assembly 3 above the ground for rotation about a vertical axis .

By way of further example, the present invention is not limited to forming the outer surfaces of the housing 13 and the rotor body 15 as dimpled surfaces to promote streamlined air flow and minimise turbulence and thereby improve performance of the rotor. By way of further example, the present invention is not limited to positioning the rotor blades 17 to extend outwardly and rearwardly at an angle of 45° to the axis of rotation of the rotor. The angle may be any suitable angle, preferable an angle in the range of 30-60°.

Claims

1. A wind turbine that comprises an assembly of an electricity generator and a rotor that is operatively coupled to the generator, the assembly being adapted to point into the wind, the rotor being rotatable about an axis that, in use, is coincident with the direction of wind that contacts the wind turbine, the rotor forming a rear end of the assembly and having blades that extend outwardly and rearwardly when viewed in the wind

direction, and the blades being shaped to convert air flow against the blades into rotary movement of the rotor that drives the generator.

2. The wind turbine defined in claim 1 wherein the electricity generator is located forwardly of the rotor.

3. The wind turbine defined in claim 1 or claim 2 wherein the generator/rotor assembly comprises a housing for the generator.

4. The wind turbine defined in claim 3 wherein the housing is shaped to minimise resistance to air flow over the housing.

5. The wind turbine defined in claim 3 or claim 4 wherein the housing is located forwardly of the rotor.

6. The wind turbine defined in claim 5 wherein the housing is shaped to minimise resistance to air flow over the housing and disturbence to air flow to the rotor.

7. The wind turbine defined in any one of the preceding claims wherein the rotor blades extend outwardly and rearwardly from the rotor axis .

8. The wind turbine defined in any one of the preceding claims wherein the rotor comprises a rotor body from which the blades extend that is operatively mounted to a

generator shaft to rotate the shaft and thereby drive the generator .

9. The wind turbine defined in claim 8 wherein the rotor body is shaped to minimise resistance to air flow over the rotor body.

10. The wind turbine defined in claim 9 wherein the shape of the rotor body is an extension of the shape of the housing so that there is a smooth transition for air flow over the housing and the rotor body.

11. The wind turbine defined in any one of claims 8 to 10 wherein an outer surface of the housing and/or an outer surface of the rotor body is formed to promote streamlined air flow and minimise turbulence and thereby improve performance .

12. The wind turbine defined in any one of the preceding claims wherein the rotor blades extend outwardly and rearwardly at an angle in a range of 30-60° to the axis of rotation of the rotor.

13. The wind turbine defined in claim 12 wherein the rotor blades have a uniform transverse cross-section along the length of the blades .

14. The wind turbine defined in claim 12 or claim 13 wherein each rotor blade is curved from a leading end to a trailing end of the blade, as viewed from the wind

direction .

15. The wind turbine defined in claim 14 wherein each rotor blade comprises a first section that curves radially outwardly from the leading end of the blade and a second section that curves radially inwardly from the first section towards the rear end of the blade, as viewed from the wind direction.

16. The wind turbine defined in any one of the preceding claims wherein the rotor blades are fixed pitch blades or variable pitch blades .

17. The wind turbine defined in any one of the preceding claims further comprises a sensing device to control the rotational speed of the rotor.

18. The wind turbine defined in any one of the preceding claims wherein the rotor comprises a ring-shaped fairing that interconnects the outer ends of the blades and thereby stabilises the blades.

19. The wind turbine defined in any one of the preceding claims further comprises a tower or a pole or other type of upwardly extending structure that supports the

generator/rotor assembly above the ground for rotation about a vertical axis of the support structure so that the assembly can rotate to point into the wind.

20. An assembly of an electricity generator and a rotor that is operatively coupled to the generator for use in a wind turbine, the assembly being adapted to point into the wind in use of the assembly in the wind turbine, the rotor being rotatable about an axis , the rotor forming a rear end of the assembly and having blades that extend

outwardly and rearwardly from a forward end of the

assembly and are shaped to convert air flow against the blades into rotary movement of the rotor that can drive the generator, the assembly comprising a housing for the generator and a rotor body that are shaped to minimise resistance to air flow over the rotor body.

21. An assembly of an electricity generator and a rotor that is operatively coupled to the generator, the assembly being adapted to point into the wind, the rotor being rotatable about an axis that, in use, is coincident with the direction of wind that contacts the wind turbine, the rotor having blades that are shaped to convert air flow against the blades into rotary movement of the rotor that drives the generator, the assembly comprising a housing for the generator and a rotor body that are shaped to minimise resistance to air flow over the rotor body, and the generator housing and/or the rotor body having outer surfaces that are formed to promote streamlined air flow and minimise turbulence and thereby improve performance.