WO2023194474A1

WO2023194474A1 - Wind engine with a horizontal rotor

Info

Publication number: WO2023194474A1
Application number: PCT/EP2023/059006
Authority: WO
Inventors: Ulrich Maier
Original assignee: Ulrich Maier
Priority date: 2022-04-08
Filing date: 2023-04-05
Publication date: 2023-10-12
Also published as: DE102022108534A1

Abstract

The invention relates to a wind engine (10) having a horizontal rotor (18) for generating usable energy from wind power. The wind engine (10) according to the invention has a horizontally arranged rotor (18) which is connected to a rotor shaft (12) by means of at least one fastening element. The wind engine also has a supporting frame (13) which is designed to rotatably mount the rotor shaft (12). An energy converter is connected to the rotor shaft (12) and designed to convert a rotational movement of the rotor shaft (12) into another form of energy. At least two vanes (11) are arranged on the rotor (18) here, the vanes being fastened to the rotor (18) in a manner rotatable about their own axis of rotation, wherein the vanes (11) are designed to convert wind energy acting on them into a rotational movement of the rotor (18). Here, the vanes (11) are fastened to the rotor (18) in that half of the vanes (11) which is at the front in the direction of rotation of the rotor (18).

Description

Wind turbine with horizontal rotor

The invention relates to a wind turbine with a horizontal rotor for generating usable energy through wind power.

Due to global warming, efforts to find sustainable, so-called “green” energy sources have been steadily intensified in recent years. Wind turbines, which generate usable, mostly electrical energy from wind, are one of the most widespread technical solutions.

Wind turbines extract energy from an air current (wind) and make it usable, for example, to operate a generator or a pump, i.e. an energy converter. The energy is extracted from the wind with the help of a rotor and rotor blades or wings attached to it, which convert the air flow of the wind into a rotary movement of the rotor. A distinction can be made between two operating principles. The use of the flow resistance of the rotor blades or wings, as in classic windmills, and the use of the buoyancy of the air-flowing rotor blades, as is known, for example, in aircraft.

With regard to the basic design, a distinction must be made between wind turbines with a vertical rotor shaft and wind turbines with a horizontal rotor shaft. In wind turbines with a horizontal rotor shaft, the rotor is arranged vertically and ideally aligned so that the wind flows vertically onto the rotor, i.e. in the direction of the rotor shaft. The rotor must always be aligned with the wind for optimal use of efficiency. This involves a lot of technical effort and the disadvantage that it is not possible to react to short-term changes in wind direction. Such wind turbines usually have rotor blades with a blade cross-section and are therefore based primarily on the use of the buoyancy of this air-flowing blade cross-section. The rotor and rotor shaft are located in a nacelle high above the ground.

Another disadvantage of wind turbines with a horizontally arranged rotor shaft is that the energy converter intended for converting the energy - usually in the form of a generator - should be provided in the nacelle, i.e. at the level of the rotor shaft. This results in the nacelle having a high mass, which leads to problems with regard to the statics, especially the buckling resistance of the machine. These problems are exacerbated by the fact that the wind pressure on the gondola poses additional major challenges to the statics. Therefore, high-strength high-tech materials, such as composite materials, are used, which often have disadvantages with regard to recycling and the general energy efficiency of the system due to energy-intensive production. In addition, all maintenance-intensive and technically fault-prone components of the wind turbine are difficult to access in the nacelle high above the ground, which also makes the maintenance of the corresponding components complex.

Wind turbines with a vertical rotor shaft, on the other hand, have a horizontally arranged rotor which rotates around the vertical rotor shaft. Thanks to the vertically arranged rotor shaft, the generator can be operated on the ground, which significantly simplifies maintenance and also reduces static requirements. However, such a design according to the prior art has the problem that due to the rotary movement of the rotor around the vertical rotor shaft, part of the rotor blades move against the wind direction and thus the rotor is braked again, which reduces the efficiency of such machines. Designs have therefore been developed in which the rotor blades can be actively rotated and, when moving against the wind, are aligned in such a way that their air resistance is minimal. However, this requires complex technology, in particular control technology, and requires additional energy to rotate the rotor blades. Such a wind turbine is disclosed, for example, in patent document DE 44 18 092 A1.

It is therefore the object of the present invention to provide a wind turbine which eliminates the disadvantages described above.

This task is solved by the subject matter of the main claim. Advantageous developments of the invention are contained in the subclaims.

The wind turbine according to the invention has a horizontally arranged rotor, in particular in ring shape, which is connected to a rotor shaft by means of at least one fastening element. Furthermore, a support frame is provided, which is designed to rotatably support the rotor shaft and preferably support the weight of the wind turbine. The wind power machine according to the invention also has an energy converter, which is connected to the rotor shaft and is designed to convert a rotational movement of the rotor shaft into another form of energy. The energy converter is preferably provided as a generator, which converts the rotational movement into electrical current. However, embodiments are also conceivable in which the energy converter is in a different form, such as a pump.

According to the invention, at least two blades arranged on the rotor are also provided, which are attached to the rotor and rotatably mounted about an axis of rotation. The axis around which the blades can rotate in relation to the rotor is called the axis of rotation. The blades function as rotor blades and are therefore designed to convert the wind energy flowing around them into a rotational movement of the rotor, which is transmitted to the rotor via the at least one fastening element between the rotor and the rotor shaft. Furthermore, the blades are attached to the rotor in the front half of the cross-sectional profile of the blades in the direction of rotation of the rotor. The cross-sectional profile relevant here is the horizontal cross section through a wing at the level where the wing is attached to the rotor. The direction of rotation of the rotor is always the same regardless of the wind direction and indicates the direction of rotation caused by the flow on the blades.

By arranging the rotor horizontally, as described in the prior art, the disadvantages of a wind turbine with a vertical arrangement of the rotor, particularly those relating to statics, can be avoided. In addition, the way the blades are attached allows them to always align with the wind on the rotor in such a way that propulsion on the rotor can be achieved. Depending on the position in the wind, at least one of the operating principles described above of exploiting the flow resistance or the buoyancy of the air-flowing wing is applied. This always generates propulsion for the rotor and does not slow it down, which means the efficiency can be significantly increased compared to conventional solutions with horizontal rotors. More details about how it works will be explained in more detail with reference to the figures.

In an advantageous embodiment of the invention, the supporting frame and/or the rotor are made of wood. Due to the statically favorable design of the wind turbine, high-tech materials can be dispensed with and more ecologically sustainable materials can be used. The material properties of wood are sufficient to provide a stable wind turbine. As a renewable raw material, wood has advantages in terms of sustainability, especially in terms of CO2 emissions and recyclability. Preferably, the rotor shaft is also at least partially made of wood.

Also advantageous is an embodiment of the invention in which the wings have a main extension direction which runs in a substantially vertical direction. Wings with the longest possible extension in this main direction of extension are preferred because the force that a wing exerts on the rotor increases with its vertical extension, since the wings thus offer the wind more effective surface. Long vertical wings are therefore preferred. Such wings are particularly advantageous if, in addition to the vertical main direction of extension, the axis of rotation of the wings also runs vertically. Such wings have a simple geometry, which brings advantages particularly in terms of efficiency and production. Preferably, the blades are further arranged centrally on the rotor, so that the attachment of the blade to the rotor is symmetrical and the rotor is located at the level of the center of the longitudinal axis of the blade.

In a further advantageous embodiment of the invention, the blades are attached to the rotor not only in the front half of the blades in the direction of rotation of the rotor, but in the front third. Alternatively or additionally, the centers of gravity of the blades are located in the front third of the blades in the direction of rotation of the rotor. An embodiment in which the pivot point of the wing cross section is located at the center of gravity is particularly preferred. The center of gravity of a body is the mass-weighted average of the positions of its mass points. For continuous mass distributions, the local average density is used as the center of gravity Are defined. This geometry enables particularly dynamic adjustment of the alignment of the blades during the rotation of the rotor.

In a further advantageous embodiment of the invention, the at least one fastening element is made from at least one rope. It is preferred if a fastening element is formed from a pair of cables, one of which is provided as a tension cable and one as a support cable. The supporting cable is provided between the rotor shaft and the rotor in such a way that it supports the weight of the rotor. It therefore has a vertically supporting component. The tension cable, on the other hand, has a purely radial component and is intended to keep the rotor stable in its position. In a preferred embodiment, the tension cable or tension cables are arranged purely horizontally between the rotor and the rotor shaft or the tension cable suspension. In the plan view, a pair of ropes consisting of a support rope and a tensioning rope preferably encloses a small angle. The use of ropes, especially steel ropes, is a light, cost-effective and comparatively simple method of fixing the rotor in its position.

In an advantageous embodiment with ropes as fastening elements, these ropes are designed to function as lightning rods for the wind turbine.

In an advantageous embodiment, the cross section of the wings can be changed perpendicular to the direction of extension. The geometry of the wing can be adjusted, particularly with regard to its curvature and length, in order to achieve optimal force development through the incoming air flow. The change in the wing can be influenced, for example in airplanes, by using appropriate flaps. Another possibility of changing the wing would be an adjustable skeleton, which is surrounded by a membrane and thus forms the wing. Other options, which should not be discussed further during registration, are also possible. However, the invention is not limited to the use of blades with a variable cross-section. Wings with a constant symmetrical or asymmetrical cross-section can also be used.

In a further advantageous embodiment of the invention, the rotor is composed of a large number of individual rotor segments, which are connected to one another in a rigid manner. This has the advantage that damage can be made possible by replacing individual damaged segments. The production of the rotor, especially for large rotors, can also be simplified in this way.

In a further advantageous embodiment of the invention, at least one damper element is provided for each wing, which is configured to dampen the rotational movement of the corresponding wing around the axis of rotation. The damper is preferably arranged between the wing and the rotor. Particularly advantageously, the damping takes place in the rear third of the blades in the direction of rotation of the rotor. In this way, comparatively simple and effective damping can be ensured. Also advantageous is an embodiment with a damping element, wherein the damping effect of the damping element is adjustable. Such damper systems are known, for example, from vehicle technology, where the damper hardness of the chassis can be adjusted depending on the driving style and needs (sporty or comfortable). It is also advantageous if the damping element can be adjusted in such a way that no rotation of the wing about its own axis of rotation is possible and the wing can thus be fixed in one position. In this way, the blades can be fixed in a position in which they exert a braking torque on the rotor, at least in some positions along the rotor. In addition, active rotation of the wings using appropriate actuators is also conceivable in order to actively influence the position of the wings. These actuators can be integrated in the damper, for example in the form of a damping piston. In addition, it makes sense to limit the maximum movement through the damping element in order to control the rotational movement of the wing.

In a further preferred embodiment of the invention, the rotor and the blades make up at least 80% of a total mass of the wind turbine. The total mass refers to the mass of the wind turbine without the foundation. Due to the high mass in the rotor and thus the moving parts, a high inertia of the rotor can be achieved, which means that it does not accelerate too quickly even in gusts of wind. This means that power peaks that cannot be absorbed by the generator, which could arise if the speed is increased too quickly, can be avoided. In addition, the stability of the arrangement can be improved. Due to the high mass of the rotor and the blades in relation to the mass of the wind turbine, they can continue to function as energy storage and thus ensure a comparatively constant or only slowly changing speed of the rotor, even in gusty winds.

Embodiments and aspects of the present invention are explained in more detail below with reference to the accompanying figures. Show it:

Fig. 1 shows an embodiment of the wind turbine 10 according to the invention in a top view.

Fig. 2 shows part of the embodiment of the wind turbine 10 according to the invention shown in Fig. 1 in a side view.

Fig. 3 shows a detailed view of a wing of the embodiment of the wind turbine 10 according to the invention shown in Fig. 1 in a top view.

Fig. 1 shows an embodiment of the wind turbine 10 according to the invention in a top view. An annular rotor 18 is connected to a central rotor shaft 12 via cables 16, 17. Several pairs of ropes are each formed from a tension rope 17 and a support rope 16. A pair of ropes always forms a small angle between them. However, other embodiments are also conceivable in which this is not the case. The ropes 16, 17 are arranged in a star shape around the rotor shaft 12 in top view. Depending on the size and weight of the rotor, the number of rope pairs can vary. The rotor shaft 12 is held and stored by a support frame 13, which is described in more detail with regard to FIG. 2.

The rotor 18 is composed of individual rotor segments 181, which are connected to one another in a rigid manner. Vanes 11 are provided along the circumference of the annular rotor 18, which will be described in more detail with reference to FIG. 3. The wings 11 are attached to the rotor 18 in such a way that they are rotatably mounted about their own axis of rotation. This means that the wings are aligned

11 according to the wind W, which comes from above in the drawing plane, possible.

The blades 11 convert the flow energy of the wind W into a rotational movement of the rotor 18. This rotational movement is transmitted to the rotor shaft via the cables 16, 17

12 transferred. To absorb the flow energy on the wind, the operating principles of lift and flow resistance of the wings mentioned above are used, depending on the position of the wing. For explanation, the rotor 18 is divided into 3 different areas in the top view. To describe the position of a blade along the circumference of the rotor 18, the dial of a clock is used.

In the right half of the rotor 18 in the plane of the drawing, i.e. between 12 and 6 o'clock, a wing 11 always represents a flow resistance for the wind, whereby a force is generated in every position, which causes the rotor 18 to rotate clockwise (in the plane of the drawing). causes.

If a wing 11 exceeds the 6 o'clock position, it moves at least partially against the wind W. By positioning the wing 11 in the wind W, similar to an airplane, a negative pressure is created on the side of the wing 11 facing away from the wind on the other side, an overpressure. This creates a lift which exerts a force on the wing 11, which acts at least partially in the direction of rotation, i.e. clockwise, of the rotor 18, whereby a torque is exerted on the rotor 18.

In an area around the 9 o'clock position, the orientation of the blade 11 changes with respect to the rotor 18. While the blade 11 is aligned between the 3 o'clock position and approximately the 9 o'clock position so that the In the direction of rotation of the rotor 18, the front half of the wing 11 points in the direction of the rotor 18, the rear part of the wing 11 shows between the 9 o'clock position and the 3 o'clock position (i.e. in the upper half of the rotor 18 in the plane of the drawing). in the direction of the rotor 18. During this rotational movement of the wing 11 about its own axis of rotation at the 9 o'clock position, which is caused solely by the flow of the wind W, the wing 11 aligns itself so that it has the lowest possible flow resistance and thus brakes the rotor 18 as little as possible. Due to the aerodynamic shape of the wing 11, the flow resistance is negligible.

In the area between the 9 o'clock position and the 12 o'clock position, after the wing 11 has been aligned by its own rotation at the 9 o'clock position, the wing 11 is positioned towards the wind W in such a way that lift is again achieved is generated by the flow of wind W, with the buoyancy force pointing to the right in the plane of the drawing. This creates the wing 11 also between the 9 o'clock position and the 12 o'clock position a force which increases the rotation of the rotor 18 in the clockwise direction.

Consequently, the vane 11 creates a force in almost every position along a revolution, which induces the rotation of the rotor 18 in the clockwise direction.

The invention is not limited to the use of an annular rotor 18. Other forms are also conceivable. Angular shapes can be used as well as direct “rigid” connections between the wing 11 and the rotor shaft 12. In the latter case, these rigid connections, for example in the form of beams, are to be viewed as both a fastening element and a rotor 18. However, annular rotors have the advantage that, due to their symmetry, they have advantages in terms of statics, especially at higher speeds of the rotor 18. Wind turbines with high outputs can therefore be built, in particular by means of an annular rotor. In addition, an annular rotor 18 can particularly preferably be connected to the rotor shaft 12 using ropes as a fastening element, as shown in FIGS. 1 to 3 shown. Of course, other types of fastening elements can also be used in conjunction with annular rotors 18 or ropes can be combined as fastening elements with other rotor shapes.

Fig. 2 shows part of the embodiment of the wind turbine 10 according to the invention shown in Fig. 1 in a side view. The rotor shaft 12 is mounted on the support frame 13 via a rotor shaft bearing 121 and connected to an energy converter. In the exemplary embodiment shown, the energy converter is designed as a generator unit 15, which converts the rotational movement of the shaft into electrical current. Depending on the design of the wind turbine, it may be necessary to provide a gearbox between the rotor shaft 12 and the generator unit 15 in order to increase the speed of the rotor shaft 12. The support frame 13 is designed as a tripod frame, which has 3 supports and supports the rotor shaft 12. The rotor shaft 12 can be shielded from the outside world and thus protected by an enclosure (not shown). In the embodiment shown, the support frame and the generator unit are firmly anchored in the ground via foundations 14.

A support cable suspension 161 and a tension cable suspension 171 are provided on the rotor shaft 12 at different heights. They are connected to the support cables 16 or tension cables 17 provided in the circumferential direction of the rotor 18. The support cable suspension 161 is arranged above the tension cable suspension 171, with the tension cable suspension 171 being located at the level of the rotor 18. Through this arrangement, the support cables 16 carry the weight of the rotor 18, while the tension cables 17 put the annular rotor 18 under tension so evenly that it cannot be deflected in the radial direction. The tension cables 17 are preferably stretched horizontally between the rotor 18 and the tension cable suspension 171. The rotational movement of the rotor 18 is transmitted through the tension cables 17 to the tension cable suspension 171 and thus to the rotor shaft 12. The horizontal arrangement of the tension cables 17 increases the stability of the system and the power transmission from the rotor 18 to the rotor shaft 12 can be improved. In this way, significantly larger systems with higher performance can be produced, especially if the support frame 13 and the rotor 12 are made of wood.

Both the support cable suspension 161 and the tension cable suspension 171 are designed as round plates in the present embodiment, with the corresponding cables 16, 17 being attached to the outer edge of the respective plate.

The blades 11 are arranged on the rotor 18, which extend in the vertical direction, i.e. parallel to the rotor shaft 12, the blades 11 being arranged centrally on the rotor 18, so that half of a blade 11 is above and the other half of the blade 11 is below the horizontal Rotor 18 is arranged. The wings 11 are therefore perpendicular to the horizontally arranged tension cable 17 between the rotor 18 and the rotor shaft 12. In the perspective shown in FIG. 2, the symmetrical wings 11 appear as flat boards. If the direction of flow of the wind W is into the plane of the drawing, the wing 11 shown has no significant wind resistance, as a result of which the rotor 18 is not braked. In order to prevent deformation of the wing 11, it is braced via outer and inner wing tensioning cables 111, 112. Deformation can occur at higher flow velocities (i.e. stronger wind), which on the one hand places additional stress on the material of the blades 11 and reduces the efficiency of the blades 11 in terms of the force generated for the feed. The inner wing tensioning cables 112 are provided on the corresponding tensioning cable 17 between the rotor 18 and rotor shaft 12, while the outer wing tensioning cables 111 are tensioned with the aid of a wing tensioning cable support 113, which extends outwards in the radial direction from the wing 11. In addition, tangential wing tensioning cables 118 can also be provided in order to further increase the stability of the wings 11 in the circumferential direction of the rotor 18.

Fig. 3 shows a detailed view of a wing 11 shown in Figs. 1 and 2 illustrated embodiment of the wind turbine 10 according to the invention in a top view. The rotor 18 is shown, which is attached to the rotor shaft 12 (not shown in FIG. 3) via the cables 16, 17. The wing 11 is fastened to the rotor 18 via a fastening element 114 by a wing bearing 115 provided thereon. The wing 11 is shown in cross section through its vertical extension direction, so that the symmetry of the wing 11 can be clearly seen. As already mentioned, the invention is not limited to the use of symmetrical wings 11; rather, wings 11 that are asymmetrical in cross section or wings 11 that can be changed in cross section can also be used. The wing 11 is braced via the wing tensioning cable support 113 and the outer wing tensioning cables 111 provided thereon, as explained with reference to FIG. 2. The inner wing tensioning cables 112 are not shown in FIG. 3 for the sake of clarity.

Through the wing bearing 115, the axis of rotation of the wing 11 extends into the plane of the drawing. In this exemplary embodiment, the axis of rotation is arranged parallel to the main vertical direction of extension of the wing 11. The wing 11 can be rotated about the axis of rotation on the rotor 18. However, this rotation is dampened and at the same time limited by a damper 116. The Maximum positions of the wing 11 are thus specified by the damper 116.

In the embodiment shown, the damper 116 is provided as a simple hydraulic cylinder, with a piston 117 guided in the cylinder being connected to the wing 11. As is known with hydraulic dampers, the damping can be adjusted, for example, via the viscosity of the fluid used in the damper 116 or via the passage in the piston from one hydraulic chamber to the other. This makes it possible to react to forces of different strengths during the rotation of the wing 11, which can be caused by winds of different strengths.

The wing 11 is mounted in the front area of the cross section in the direction of rotation of the rotor 18, more precisely in the front half of the cross section. This ensures that the wind pressure causes the blades 11 to be rotated at the correct times (see comments on FIG. 1) and thus a force acts on the rotor 18 in its direction of rotation at all times. The damper 116 engages in the rear half of the cross section. Of course, other types of damping can also be provided, which is arranged, for example, in the mounting of the wing 11 on the fastening element 114 itself. Preferably, the maximum deflection of the wing 11 is also defined by the damper 116, so that the damper 116 also functions as a stop.

Embodiments of the invention are also conceivable in which, instead of a damper, a stop that is adjustable by means of an electric motor and a spindle, in particular a threaded spindle, is provided. The stop defines the maximum positions of the rotary movement of the wing 11. The stop can be adjusted by the electric motor and the threaded spindle and the rotary movement of the wing 11 can thus be controlled. The spindle preferably has a damping section made of a soft, flexible material at the point where it comes into contact with the wing 11, so that damage to the wing 11 can be avoided.

REFERENCE SYMBOL LIST

10 wind turbine

11 wings

111 outer wing tension cable

112 inner wing tension cable

113 Wing tension cable support

114 fastener

115 wing bearing

116 damping element

117 damper pistons

118 tangential wing tension cable

12 rotor shaft

121 rotor shaft bearings

13 carrying frame

14 foundation

15 generator unit

16 suspension cable

161 Suspension cable suspension

17 tension rope

171 tension cable suspension

18 rotor

181 rotor segment

W wind

Claims

PATENT CLAIMS

1 . Wind turbine (10) comprising a horizontally arranged rotor (18), which is connected to a rotor shaft (12) by means of at least one fastening element, a support frame (13) designed to rotatably support the rotor shaft (12), an energy converter which is connected to the Rotor shaft (12) is connected and is designed to convert a rotational movement of the rotor shaft (12) into another form of energy, at least two vanes (11) arranged on the rotor (18), which are rotatably attached to the rotor (18) about an axis of rotation, wherein the blades (11) are designed to convert wind energy acting on them into a rotational movement of the rotor (18), the blades (11) also being in the front half of the blades (11) on the rotor (18) in the direction of rotation of the rotor (18). 18) are attached.

2. Wind turbine (10) according to claim 1, wherein the support frame (13) and / or the rotor (18) are made of wood.

3. Wind turbine (10) according to one of the preceding claims, wherein a main direction of extension of the blades (11) runs in a vertical direction and in particular the axis of rotation runs parallel to the main direction of extension.

4. Wind turbine (10) according to one of the preceding claims, wherein the blades (11) are attached to the rotor (18) in the front third of the blades (11) in the direction of rotation of the rotor (18) and / or the centers of gravity of the blades (11 ) are located in the front third of the blades (11) in the direction of rotation of the rotor (18).

5. Wind turbine (10) according to one of the preceding claims, wherein the at least one fastening element is designed as a rope (16, 17), in particular as a pair of ropes (16, 17), and one of which is designed as a tension rope (17) and one as Support cable (16) is provided, the tension cable (17) being connected to the rotor shaft (12) at a different point than the support cable (16).

6. Wind turbine (10) according to the preceding claim, wherein the tension cable (17) is arranged horizontally between the rotor shaft (12) and the rotor (18) and is prestressed. Wind turbine (10) according to the preceding claim, wherein a pair of tension cable (17) and support cable (16) are arranged such that they enclose an angle between them. Wind turbine (10) according to one of the preceding claims, wherein the cross section of the blades (11) can be changed perpendicular to the direction of extension. Wind turbine (10) according to one of the preceding claims, wherein the rotor (18) is composed of individual rotor segments (181). Wind turbine (10) according to one of the preceding claims, wherein for each blade (11) at least one damper (116) is provided, which is configured to dampen the rotational movement of the corresponding blade (11) about the axis of rotation, the damper (116 ) is arranged in particular between the wing (11) and the rotor (18) and particularly preferably the damping of the rotary movement of the wing (11) takes place in the rear third of the wing (11) in the direction of rotation of the rotor (18). Wind turbine (10) according to one of the preceding claims, wherein the damper (116) has variable damping and/or determines the maximum movement of the corresponding blade (11). Wind turbine (10) according to one of the preceding claims, wherein the rotor (12) and the blades (11) make up at least 80% of a total mass of the wind turbine (10).