ROTOR FOR A WIND TURBINE AND WIND TURBINE

Abstract

A rotor for a wind turbine, in particular a wind turbine, having a power of more than 1 MW, to a hub for a rotor of a wind turbine and to a wind turbine. A rotor for a wind turbine, in particular a wind turbine having a power of more than 1 MW, comprising a primary rotor blade, wherein the primary rotor blade extends from a first root region to a first blade tip having a first longitudinal extension, a secondary rotor blade, wherein the secondary rotor blade extends from a second root region to a second blade tip having a second longitudinal extension, the first longitudinal extension being larger than the second longitudinal extension.

Claims

1. A rotor for a wind turbine, comprising: a primary rotor blade, the primary rotor blade extending with a first longitudinal extent from a first root region to a first blade tip, and a secondary rotor blade, the secondary rotor blade extending with a second longitudinal extent from a second root region to a second blade tip, the first longitudinal extent being greater than the second longitudinal extent.

2. The rotor as claimed in claim 1, wherein a ratio of the second longitudinal extent to the first longitudinal extent is less than 0.75.

3. The rotor as claimed in claim 1, wherein: the primary rotor blade has a pitch adjustment for rotational movement about a longitudinal axis of the primary rotor blade, and the secondary rotor blade has a pitch adjustment for rotational movement about a longitudinal axis of the secondary rotor blade.

4. The rotor as claimed in claim 1, wherein the primary rotor blade and the secondary rotor blade are coupled to a hub.

5. The rotor as claimed in claim 1, wherein: the primary rotor blade has a first longitudinal axis which ii oriented between the first root region and the first blade tip, and wherein the secondary rotor blade has a second longitudinal axis oriented between the second root region and the second blade tip, and the first longitudinal axis and the second longitudinal axis enclose an angle parallel to the rotational direction, and/or the rotor has a rotational axis, and wherein the first longitudinal axis and the second longitudinal axis enclose substantially an angle of identical magnitude with the rotational axis.

6. The rotor as claimed in claim 1, wherein the primary rotor blade comprises a structural section starting from the first root region and extends with a structural section length in a direction of the first blade tip, and wherein the structural section has an induction factor that is less than 0.3.

7. The rotor as claimed in claim 6, wherein the second longitudinal extent is greater than the structural section length.

8. The rotor as claimed in claim 1, wherein the secondary rotor blade has an induction factor between 0 and 0.4.

9. The rotor as claimed in claim 1, comprising two primary rotor blades and two secondary rotor blades, the two primary rotor blades and the two secondary rotor blades being arranged adjacently with respect to one another, and in each case enclosing a 90° angle.

10. The rotor as claimed in claim 1, comprising three primary rotor blades and three secondary rotor blades, the three primary rotor blades and the three secondary rotor blades being arranged adjacently with respect to one another, and in each case enclosing a 60° angle.

11. The rotor as claimed in claim 1, wherein at least one high lift system is arranged on the secondary rotor blade, the at least one high lift system comprising or configured as one or more of: a plurality of slats, a plurality of slotted caps, a plurality of Fowler flaps, a plurality of vortex generators, and/or a plurality of Gurney flaps.

12. A hub comprising: the rotor as claimed in claim 1, at least three primary connector points configured for coupling with primary rotor blades, including the primary rotor blade, and at least three secondary connector points configured for coupling to secondary rotor blades, including the secondary rotor blade.

13. A wind turbine, comprising a tower, and a nacelle arranged on the tower, wherein the nacelle includes the rotor as claimed in claim 1.

14. The rotor as claimed in claim 1, wherein the wind turbine has a power output of more than 1 megawatt (MW).

15. The rotor as claimed in claim 2, wherein the ratio is less than 0.1

16. The rotor as claimed in claim 3, wherein the secondary rotor blade provides a stall-controlled configuration.

17. The rotor as claimed in claim 6, wherein the induction factor is less than 0.2.

18. The rotor as claimed in claim 8, wherein the secondary rotor blade has, in a region adjacent to the second blade tip, an induction factor of less than 0.1, and, in a region adjoining the second root region, an induction factor between 0.25 and 0.4.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0049] Preferred exemplary embodiments will be explained by way of example on the basis of the appended figures, in which:

[0050] FIG. 1 shows a diagrammatic view of a wind turbine,

[0051] FIG. 2 shows a diagrammatic view of a further wind turbine with diagrammatically illustrated induction factors, and

[0052] FIG. 3 shows a diagrammatic view of a wind turbine known in the prior art with diagrammatically illustrated induction factors.

DETAILED DESCRIPTION

[0053] FIG. 1 shows a diagrammatic illustration of a wind turbine. The wind turbine 100 has a tower 102 and a nacelle 104 on the tower 102. An aerodynamic rotor 106 with three primary rotor blades 108 and three secondary rotor blades 112 and a spinner 110 is provided in the nacelle 104. During operation of the wind turbine 100, the aerodynamic rotor 106 is set in a rotational movement by way of the wind, and therefore also rotates an electrodynamic rotor or runner of a generator which is coupled directly or indirectly to the aerodynamic rotor 106. The electric generator is arranged in the nacelle 104 and generates electrical energy. The pitch angles of the primary rotor blades 108 can be changed by way of pitch motors on the rotor blade roots of the respective primary rotor blades 108.

[0054] The primary rotor blades 108 preferably have an induction factor of approximately ⅓ in a region beginning at the respective blade tip toward a structural section. In the structural section, the primary rotor blades 108 are designed substantially for meeting structural requirements, and can have an induction factor of considerably below ⅓ here. The secondary rotor blades 112 have a smaller longitudinal extent than the primary rotor blades 108. Moreover, the secondary rotor blades in each case have an induction factor of ⅓ adjacently with respect to the root region, and an induction factor of zero at the blade tip. The sum of the induction factor of the primary rotor blade and of the secondary rotor blade preferably adds up to ⅓ for each distance from the hub. That proportion of the rotor 106, in which the induction factor therefore lies below ⅓, in particular clearly below ⅓, is decreased in the case of the present rotor 106 in comparison with known rotors.

[0055] FIG. 2 shows a diagrammatic view of a further wind turbine with diagrammatically illustrated induction factors. The wind turbine 200 has a tower 202 with a rotor 206. The rotor has a spinner 210 in the region of its rotational axis. The rotor comprises a first primary rotor blade 220, a second primary rotor blade 222, and a third primary rotor blade 224. The rotor 206 rotates about a rotational axis, with the result that the primary rotor blades 220, 222, 224 move in the rotational direction 208.

[0056] The construction of a primary rotor blade will be explained in the following text using the example of the third primary rotor blade 224. The third primary rotor blade 224 extends from a blade tip 225 toward a root region 226. The blade tip and the root region are to be understood, in particular, to be ends of the third primary rotor blade 224.

[0057] In a region close to the hub of the third primary rotor blade 224, the latter has a structural section 227 which, starting from the root region 227, extends with a structural section length in the direction of the blade tip 225 and is shown using dashed lines in the present case. The structural section 227 is distinguished by the fact that it has a small induction factor. In particular, the induction factor of the structural section 227 can be smaller than 0.3 and/or smaller than 0.25 and/or smaller than 0.2.

[0058] That section of the third primary rotor blade 224 which adjoins the structural section 227 in the direction of the blade tip 225 preferably has an induction factor of approximately ⅓. In particular, the induction factor in this region can be between 0.25 and 0.5, in particular between 0.25 and 0.35. In a section which adjoins the blade tip 225, the third primary rotor blade 224 therefore has a substantially optimum induction factor which makes optimum-power operation of the wind turbine 200 possible. In a region close to the hub, in particular in a radius which corresponds to the structural section length 227, the primary rotor blades 220, 222, 224 are not of optimum-induction design, however.

[0059] Furthermore, the rotor 206 has the first secondary rotor blade 230, the second secondary rotor blade 232 and the third secondary rotor blade 234. The secondary rotor blades 230, 232, 234 have a considerably smaller longitudinal extent than the primary rotor blades 220, 222, 224. At the respective blade tip, the secondary rotor blades 230, 232, 234 have an induction factor of zero which then rises successively toward the root region to a value of from 0.25 to 0.35, in particular ⅓.

[0060] The root regions of the secondary rotors 230, 232, 234 are subjected to smaller bending torques due to the considerably smaller longitudinal extent. As a consequence, they can be configured with a smaller relative profile thickness, and therefore higher glide ratios can be achieved. Therefore, the region of a non-optimum induction factor migrates in the direction of the hub, and the overall region of an optimum induction factor is increased. This is shown diagrammatically in FIG. 2 on the basis of the first induction factor region 240 and the second induction factor region 250. The first induction factor region 240 is that region of the rotor or the rotor blades, in which a substantially optimum induction factor, in particular of ⅓, is achieved. The second induction factor region 250 is that region of the rotor 206 or the rotor blades, in which there is a deviation from the optimum induction factor; here, in particular, the induction factor is smaller than ⅓.

[0061] In comparison with this, FIG. 3 shows a conventional wind turbine 300 with a tower 302 and a rotor 306, the rotor having a first rotor blade 320, a second rotor blade 322 and a third rotor blade 324. The rotor 306 does not have any secondary rotor blades. It can be seen that a considerably larger second induction factor region 350 is produced by way of that region of the rotor blades 320, 322, 324 which is close to the hub, in which second induction factor region 350 an optimum induction factor of ⅓ is not achieved. The first induction factor region 340, in which an optimum induction factor can be achieved, is correspondingly smaller. As a consequence, the aerodynamic performance of the rotor 306 is lower than the aerodynamic performance of the rotor 206 from the wind turbine 200 which is shown in FIG. 2.

LIST OF DESIGNATIONS

[0062] 100 Wind turbine [0063] 102 Tower [0064] 104 Nacelle [0065] 106 Rotor [0066] 108 Primary rotor blades [0067] 110 Spinner [0068] 112 Secondary rotor blades [0069] 200 Wind turbine [0070] 202 Tower [0071] 206 Rotor [0072] 208 Rotational direction [0073] 210 Spinner [0074] 220 First primary rotor blade [0075] 222 Second primary rotor blade [0076] 224 Third primary rotor blade [0077] 225 Blade tip [0078] 226 Root region [0079] 227 Structural section [0080] 230 First secondary rotor blade [0081] 232 Second secondary rotor blade [0082] 234 Third secondary rotor blade [0083] 240 First induction factor range [0084] 250 Second induction factor range [0085] 300 Wind turbine [0086] 302 Tower [0087] 306 Rotor [0088] 310 Spinner [0089] 320 First rotor blade [0090] 322 Second rotor blade [0091] 324 Third rotor blade [0092] 340 First induction factor region [0093] 350 Second induction factor region