DE102010037706A1 - Mast for supporting rotor of wind turbine, has mast main structure whose flexural rigidity is greater along direction perpendicular to longitudinal axis of the mast main structure - Google Patents

Abstract

The mast (2) has a mast main structure that is extended along a longitudinal axis (A) so as to support a rotor (100) of a wind turbine (1). The longitudinal axis of mast main structure is perpendicular to the longitudinal axis (A') of the rotor. The flexural rigidity of mast main structure is greater along direction (R) perpendicular to longitudinal axis of the mast main structure.

Description

The invention relates to a mast for a wind turbine according to the preamble of claim 1 and a wind turbine.

Typically, a wind turbine for converting wind energy into electrical energy has a mast extended along a longitudinal axis (vertical) for carrying at least one rotor of the wind turbine.

Such a mast is from the DE 10 2009 007 812 A1 known. Therein a wind turbine with a tower is disclosed, which carries at its upper end a wind turbine with a propeller, wherein the tower has a wind-slippery profiling in an area adjoining the wind turbine.

Wind turbines with different capacities already occupy a firm place in the mix of energy production. Due to the further development of recent years, these wind turbines have become ever larger and more efficient.

Power generating wind turbines with horizontal axis of rotation are at an appropriate height, z. B. between 50 and 140 m, positioned and aligned to the wind. Corresponding masts are preferably made of sheet steel and generally have a circular cross-section. Due to the comparatively large overall heights of wind turbines or diameters of wind turbines, two challenges increasingly come to the fore in generic wind turbines: Firstly, the use of materials and the cost of masts with increasing height grow disproportionately, on the other hand, the windstow caused by the mast, wind shadow or turbulence unfavorable to the turbine and the overall system.

Proceeding from this, the present invention is based on the problem to provide a mast or a wind turbine of the type mentioned, which is the most cost-effective in the production of maintaining a high efficiency in the production of electricity from wind energy.

This problem is solved by a mast with the features of claim 1 and by a wind turbine with the features of claim 9.

Thereafter, it is provided that the flexural rigidity and / or bending strength of the mast with respect to the longitudinal axis of the mast along the entire length (relative to the longitudinal axis) of the mast in a direction oriented perpendicular to the longitudinal axis first direction is always greater than in a direction to the first and to the longitudinal axis perpendicular second direction.

Bending stiffness is generally understood in technical mechanics as the resistance that a body opposes to a bend (in the present case perpendicular to the longitudinal axis).

In the present case, said first direction coincides in particular with the main loading direction of the mast, which is defined by the respective wind direction. In other words, the mast is designed so that it bends in the first direction (main load direction) by corresponding, approximately parallel to the first direction (wind) forces, the entire length of the mast along the longitudinal axis of the mast and at Turbine (rotor) can attack, always a greater resistance opposes, as transverse to this direction (second direction).

According to the invention, a punctiform or rotationally symmetrical (annular) cross section of the conventional masts, usually made of sheet steel (so-called tubular steel masts or tubular steel towers) can thus be avoided in particular. Such masts are oversized by design transverse to the wind direction, resulting in a correspondingly higher material usage and thus higher manufacturing costs. This problem is becoming increasingly important in modern multi-megawatt wind turbines, since experience has shown that the production costs of steel tubular masts increase disproportionately with the overall height of wind turbines.

In addition, the transport of circular masts and mast segments is very complex. Especially the transport by bridges limits the size of the transportable components. The production of tubular masts on a construction site is also very difficult. Here, the inventive design of the mast provides a remedy, because it allows in principle a reduction in the dimension (diameter) of the mast transverse to the first direction (main load direction).

In a variant of the invention, it is provided that at least one section of the mast extended along the longitudinal axis or the entire mast relative to a base (foundation) of the wind energy installation or the mast, via which the mast can be anchored in a subsoil, about the longitudinal axis is rotatable, wherein said portion of the mast or the entire mast in particular via a pivot bearing, which is in particular a so-called azimuth pivot bearing, is connected to said base.

In other words, the mast can thus be rotated together with the rotor carrier or a wind turbine, so that the said first direction represents an orientable preferred direction for the load of the mast.

In contrast, since the wind can come from all directions, a rigidly grounded mast must be equally suitable for absorbing bending moments and transverse forces from all directions.

The rotor, which is rotatably mounted about a rotor axis that is in particular horizontal, perpendicular to the longitudinal axis, can be connected to the mast via a rotor carrier, which can furthermore have a housing for accommodating a generator (turbine), with the aid of which the rotation of the rotor can be converted into electrical energy can.

In this case, in a further variant of the invention, the mast is additionally rotatable relative to the rotor carrier about the longitudinal axis, wherein the mast in particular via a rotary bearing, which is in particular designed as an azimuth rotary bearing, with the rotor carrier is connectable.

This makes it possible for the mast to be rotatable independently of the rotor carrier or of a wind turbine about the longitudinal axis of the mast.

At windward wind turbines, a windstorm forms in front of the mast and at leeward systems behind the mast, a slipstream that leads to dynamic loads on the turbine and the entire system when the rotor (turbine blade) passes by. This and any active compensation measures (eg cyclic pitch adjustment of the rotor or the rotor blades) can reduce the energy harvest and shorten the service life of the components and materials used. The possible lifetime shortening can be compensated by greater dimensioning of the components and assemblies, which, however, leads to higher system costs.

Preferably, therefore, the mast in cross-section on a cross-sectional contour (cross-sectional profile), which is preferably windschlüpfrig. In this case, the cross-sectional contour preferably has a longitudinal axis, which is preferably oriented along the said first direction during the intended operation of the wind energy plant, and in particular is greater than a transverse axis of the cross-sectional contour running transversely to the longitudinal axis of the cross-sectional contour. Preferably, the cross-sectional contour is further formed mirror-symmetrically to the longitudinal axis of the cross-sectional contour.

The cross-sectional contour can have such a wind-slippery cross-sectional contour along the entire length of the mast. However, it is also conceivable to let the mast proceed from the base in the direction of a rotor carrier from such a wind-slippery profile into a circular profile and vice versa.

Due to the resulting low flow resistance of the mast the windstow or -schwatten is reduced.

Reduced windstorms or slipstreams reduce the dynamic impact on the turbine (generator) and overall system, resulting in reduced material fatigue and extended life.

The lower dynamic loading of the turbine and the entire system also allows the use of smaller dimensioned components and assemblies and therefore allows cost savings.

Furthermore, by the deviation of the cross-sectional contour of the circular shape, the use of starting material for the production of poles is possible, which is easier to transport to the site.

Finally, the assembly and erection of non-circular masts on the jobsite is much easier.

The mast according to the invention preferably has a supporting structure with a pressure belt extended along the longitudinal axis and a tension belt extending along the longitudinal axis, the tension belt and the pressure belt being connected to one another, in particular via at least one reinforcement.

Preferably, the pressure belt and / or the tension belt that support structure each form a shell of the mast with an outwardly facing visible surface of the mast or a component of such a shell.

Alternatively, the support structure may form a skeleton of the mast, which is in particular partially or completely surrounded by a lining of the mast. The cladding may have a circular cross-sectional contour or said aerodynamic cross-sectional contour (see above) in a plane lying perpendicular to the longitudinal axis of the mast.

Preferably, the mast is designed as a sandwich part, that is produced by a sandwich construction.

In this case, a sandwich construction is understood to mean, in particular, a construction in which, for example, supporting structures such as the straps are connected to one another by a spacer material, which ensures the spacing of the two structures from one another. Thus, for example, the straps of a mast according to the invention, which are stretched along the longitudinal axis, may be surrounded by a hard foam layer or other spacer material, wherein this foam layer may in turn be surrounded by a lining. The foam layer keeps the two straps at a distance. Such a spacer material may also be arranged only between the straps.

From the elementary beam theory it is known that circular cross-sections with respect to sandwich cross sections have four times the maximum stress in the edge fibers for the same material area and height. When using a mast with a sandwich cross-section and the same material-related maximum stresses in the edge fiber, the use of a mast with sandwich cross-section therefore allows considerable material and cost savings.

Further features and advantages of the invention will be explained by means of the following description of exemplary embodiments with reference to the figures. Show it:

1A - 1C sectional views along the lines II of the figures 5A - 5C a mast of a wind turbine according to the invention with a support structure and different cross-sectional contours;

2 a sectional view along the lines II of 5A to 5C a further embodiment of a mast, with shell-like tension and compression straps of a support structure of the mast;

3A - 3D sectional views of a support structure of four embodiments of a mast, wherein each of the tension belt is connected via at least one reinforcement with the pressure belt;

4A - 4B alternative exemplary longitudinal sections along the line IV-IV of 3A by a mast of a wind turbine with exemplary reinforcements in the form of a rib or a thrust plate; and

5A - 5C schematic side views of three embodiments of a mast according to the invention or a wind turbine according to the invention.

The 5A shows in connection with the 1A to 4B a side view of an embodiment of a wind turbine according to the invention 1 , with a base 200 about a mast 2 the wind turbine 1 can be fixed to a substrate U, wherein the mast 2 extends along a longitudinal axis A, the at a normal operation of the wind turbine 1 coincides with the vertical and along the longitudinal axis A has a length L, which may in particular assume any value up to 300 m, preferably L is in the range of 50 m to 150 m. Generally, the mast 2 be formed in one piece or from individual segments, which are lined up along the longitudinal axis A and connected to each other.

The mast 2 also has a first free end via an azimuth pivot 22 with the base 200 connected, so the mast 2 around the longitudinal axis 2 opposite the ground U or the base 200 is rotatable, with the mast 2 from the first free end along the longitudinal axis A to a second free end of the mast 2 extends over which the mast 2 with a rotor carrier 101 (or a wind turbine) is rotatably connected. At the rotor carrier 101 (also called gondola) is a rotor 100 the wind turbine 1 about a rotor axis A 'rotatably mounted, wherein the rotor axis A' at a normal operation of the wind turbine 1 runs along the horizontal. The rotor carrier 101 may further receive a generator (not shown) which controls the rotational energy of the rotor 100 converted into electrical energy.

5B shows a modification of the wind turbine 1 according to 5A , unlike the wind turbine 1 according to 5A the pivot bearing 22 not in the area of the first free end of the mast 2 is provided, but at any height, z. B. approximately in the middle of the mast 2 , Ie. the mast 2 has a first (lower) section over which the mast 2 is connected to the underground U, and an adjoining second section 21 that goes to the second free end of the mast 2 or to the rotor carrier 101 extends, the two sections of the mast 2 over the pivot bearing 22 are joined together so that the (upper) second section 21 of the mast 2 including rotor carrier 101 relative to the rotatably connected to the substrate U first portion of the mast 2 can be rotated about the longitudinal axis A.

Finally shows 5C another modification of the wind turbine 1 according to 5A , unlike the wind turbine 1 according to 5A additionally the rotor carrier 101 via an azimuth pivot 20 with the (upper) second free end of the mast 2 connected, so the mast 2 independent of the rotor carrier 101 is rotatable about the longitudinal axis A.

The 1A to 3D show possible exemplary cross-sectional contours 30 of the mast 2 or a support structure 23 of the mast 2 along the lines II the 5A to 5C ,

After that, the mast points 2 according to 1A to 2 a support structure 23 on, with a tension belt 25 and a pressure belt 24 which are each extended along the longitudinal axis A. This is shown by the masts 2 according to the figures 1A to 1C each a disguise 28 on which the support structure 23 in cross-section surrounds, so that the mast 2 according to 1A for example, a circular cross-sectional contour (outer contour) 30 based on the appearance of conventional masts may have. The 1B and 1C In contrast, show load- and flow-optimized cross-sectional contours, wherein 1B an oval cross-sectional contour 30 and 1C an (aerodynamic) drop-like cross-sectional contour 30 shows where each extension along the longitudinal axis 31 is greater than along the transverse axis 32 ,

Here, the cross-sectional contour 30 according to 1C respectively. 2 a profile nose with a nose radius, wherein the profile nose on both sides of the contour 30 Profile limb depart, the longitudinal axis 31 the contour 30 are formed mirror-symmetrically and at an acute angle (eg., On the pressure belt 24 according to 2 ) converge.

The tension belt 25 and the pressure belt 24 can according to the 1A to 1C be executed in skeleton construction, wherein the cladding 28 in this case preferably the support structure 23 of the relevant mast 2 completely disguised to the outside.

Alternatively, the tension and compression belt 25 . 24 according to 2 also be manufactured in shell construction. Here form the tension belt 25 and the pressure belt 24 each bowls 27 with an outwardly facing outermost and visible surface 27a of the mast 2 that have a disguise 28 connected to each other, with the cladding on both sides of the mast 2 the two bowls 27 connects with each other. The cladding can also be used as reinforcement 26 act over which the two shells 27 (Tension and compression belt 25 . 24 ) are supported against each other.

In other words, the (outer) paneling 28 Parts of the cross-sectional contour (outer contour) 30 ( 2 ) or the entire cross-sectional contour (outer contour) 30 ( 1A to 1C ).

As in the 3A to 3D shown, the tension and compression straps 25 . 24 with one or more reinforcements 26 be supported against each other.

It can according to 3A the reinforcement 26 lie inside, so z. B. of the convex curved in cross-belts 25 . 24 be encompassed in cross section, the reinforcement 26 each center of two facing inner sides 25a . 24a the two straps 25 . 24 go and connect them together.

Alternatively, the gain 26 the cross-sectional contour (outer contour) 30 follow, with two reinforcing elements 26 two opposite free ends of the two straps 25 . 24 connect with each other, or intersect, again two reinforcing elements 26 that can be connected in the middle, so that the reinforcement 26 may be formed in cross-section X-shaped, two diametrically opposite free ends of the two straps 25 . 24 connect with each other.

Furthermore, according to 3D two or more parallel reinforcements 26 by type 3A be provided.

The 4A and 4B each show an example in a sectional view along the line IV-IV of 3A reinforcements 26 between the straps 25 . 24 as they according to the 3A - 3D can be present.

After that, the gain 26 according to the 3A to 3D as a lattice structure with a plurality of lattice struts 26 be formed, which can extend along the longitudinal axis A inclined and each between the opposing straps 25 . 24 extend and connect them together (cf. 4A ).

Alternatively, the gain 26 according to 4B be formed flat, in particular of a (steel) sheet, wherein the planar reinforcement 26 relief openings 29 can have.

To a particularly high degree of material and cost savings through a load- and / or flow-optimized mast 2 with a cross-sectional contour 30 that z. B. the 1B . 1C or 2 it is appropriate to achieve the mast 2 according to the main wind direction and the main load, so that the example in 2 drawn first direction R, along the mast 2 greater axial moments of resistance or bending stiffness (bending strength), as along the oriented transversely to the first direction R second direction R ', always on the respective wind direction (main load direction) can be set (rotated) can be.

For this purpose, the azimuth pivot bearing described above 20 . 22 according to the 5A to 5C intended. The deep-seated azimuth rotary bearing makes this possible 22 after the 5A and 5B the adjustment of the azimuth angle (angle of rotation about the longitudinal axis A) of the mast 2 together with the rotor arm 101 or a wind turbine. An additional pivot bearing 20 according to 5C in addition, allows the mast 2 independent of the rotor carrier 101 to be able to turn.

Present is one of the preferred materials for the mast 2 the straps 25 . 24 and the reinforcements 26 as well as possibly other components metal, in particular steel.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009007812 A1 [0003]

Claims (10)

Mast for a wind turbine extending along a longitudinal axis (A), the mast ( 2 ) along the longitudinal axis (A) has a length (L), characterized in that the flexural rigidity of the mast ( 2 ) with respect to the longitudinal axis (A) of the mast ( 2 ) substantially along the entire length (L) of the mast ( 2 ) is greater in a first direction (R) oriented perpendicular to the longitudinal axis (A) than in a second direction (R ') running perpendicular to the first direction (R) and to the longitudinal axis (A). Mast according to claim 1, characterized in that at least one section ( 21 ) of the mast ( 2 ) or the entire mast ( 2 ) is provided and intended relative to a base ( 200 ) of the mast ( 2 ) about which the mast ( 2 ) is connectable to a substrate (U) about the longitudinal axis (A) of the mast ( 2 ), said section ( 21 ) of the mast ( 2 ) or the entire mast ( 2 ) in particular via a pivot bearing ( 22 ), in particular in the form of an azimuth pivot bearing, with the base ( 200 ) connected is. Mast according to one of the preceding claims, characterized in that the mast ( 2 ) at a free end a pivot bearing ( 20 ) over which the mast ( 2 ) with a rotor carrier ( 101 ) for supporting a rotor ( 100 ) of a wind turbine ( 1 ) is connectable, so that the mast ( 2 ) relative to the rotor carrier ( 101 ) is rotatable about the longitudinal axis (A). Mast according to one of the preceding claims, characterized in that the mast ( 2 ), in particular along its entire length (L), an aerodynamic cross-sectional contour ( 30 ), with a longitudinal axis ( 31 ), which in particular is larger than one perpendicular to the longitudinal axis ( 31 ) of the cross-sectional contour ( 30 ) transverse axis ( 32 ) of the cross-sectional contour ( 30 ), and wherein the cross-sectional contour ( 30 ) in particular mirror-symmetrical to the longitudinal axis ( 31 ) of the cross-sectional contour ( 30 ) is trained. Mast according to one of the preceding claims, characterized in that the mast ( 2 ) a supporting structure ( 23 ) with at least one pressure belt (14) extending along the longitudinal axis (A) 24 ) and at least one along the longitudinal axis (A) extended tension belt ( 25 ), wherein the at least one pressure belt ( 24 ) and the at least one tension belt ( 25 ) in particular via at least one the pressure belt ( 24 ) with the tension belt ( 25 ) connecting reinforcement ( 26 ) are supported against each other, and wherein the mast ( 2 ) in particular has a plurality of pressure and / or Zuggurte extending along the longitudinal axis (A). Mast according to claim 5, characterized in that the pressure belt ( 24 ) and / or the tension belt ( 25 ) a bowl ( 27 ) of the mast ( 2 ) with an outwardly facing surface ( 27a ) of the mast ( 2 ) form. Mast according to claim 5, characterized in that the supporting structure ( 23 ) a skeleton of the mast ( 2 ), which in particular partially or completely from a cladding ( 28 ) of the mast ( 2 ) is surrounded. Mast according to one of the preceding claims, characterized in that the mast ( 2 ) is manufactured in sandwich construction. Wind turbine, with a mast ( 2 ) according to any one of the preceding claims. Wind energy plant according to claim 9, characterized in that the wind energy plant ( 1 ) a rotor carrier ( 101 ) for supporting a rotor ( 100 ), wherein the rotor carrier ( 101 ) in particular rotationally fixed with the mast ( 2 ), or wherein the rotor carrier ( 101 ) in particular via a pivot bearing ( 20 ) with the mast ( 2 ) connected is.

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