WO2013102620A1

WO2013102620A1 - Wind turbine

Info

Publication number: WO2013102620A1
Application number: PCT/EP2013/000011
Authority: WO
Inventors: Stock JÜRGEN; Roland Mahler
Original assignee: Stock Juergen; Roland Mahler
Priority date: 2012-01-06
Filing date: 2013-01-04
Publication date: 2013-07-11
Also published as: EP2800899A1; DE102012000135A1

Abstract

The invention relates to a wind turbine comprising a rotor (26), which comprises a shaft (2) and a plurality of rotor blades (8) and is rotatable about an axis of rotation, wherein each rotor blade (8) is fastened on the shaft (2) via at least one rotor arm (4) associated with the rotor blade (8), which wind turbine is characterized in that at least one control arm (14) associated with the rotor blade (8) is fastened on each rotor blade (8), and at least one control arm (14) of each rotor blade (8) is fastened on a common connecting element (16), which is arranged in a control position which is offset with respect to the axis of rotation, with the result that an angle between each rotor blade (8) and the at least one rotor arm (14) associated therewith changes as the rotor (26) revolves around the axis of rotation.

Description

Wind turbine

The invention relates to a wind turbine with a rotor comprising a shaft and a plurality of rotor blades and is rotatable about an axis of rotation, wherein each rotor blade is secured to the shaft via at least one rotor arm associated with the rotor blade.

Wind turbines are known from the prior art and have been in use for many years. In conventional wind turbines, the axis of rotation of the rotor runs in the horizontal direction. The rotor itself usually comprises three rotor blades, which extend in the radial direction away from the shaft carrying them and rotate in a substantially vertical plane about the axis of rotation. The individual rotor blades are equipped with a profile that allows optimal use of wind energy for this type of wind turbines in a certain wind speed range. The disadvantage, however, is that optimal utilization of wind energy is only possible if the axis of rotation is parallel to the wind direction, so that in this type of wind turbines the nacelle must be tracked with the entire rotor of the wind direction, should this change. In addition, such rotors can be used only in a relatively small wind speed range. Too small wind speeds are not able to turn the large rotors at sufficient speed, while too high wind speeds pose a risk to the rotor blades. Nowadays rotors are built, which have a wing length of more than 60 meters. With such large rotors, the wing tips reach very high speeds even at moderate wind speeds. Therefore, it is no longer possible from a certain wind strength to operate the rotors safely and non-destructive.

This problem does not occur in so-called vertical axis wind turbines (VAWT "vertical axes wind turbine"). "Unlike conventional wind turbines with a horizontal axis of rotation, in a vertical axis wind turbine the rotor blades extend along the axis of rotation egg-

CONFIRMATION COPY NEN disadvantage. The rotor blades move on a circular path and, when the vertical rotor is swept by the wind over its entire width, run once in a "backward direction" with the wind and in a "backward direction" against the wind. The rotor blades cause a braking effect during the movement "reverse direction" due to their flow resistance, which can decisively reduce the efficiency compared to a horizontal rotor.

In the prior art, attempts have been made to minimize this effect to a large extent by trying to equip the rotor blades with different flow resistances, depending on the direction in which they move.

In a Savonius rotor, the individual rotor blades consist of U-shaped elements in cross-section. These are arranged so that when the rotor blade is moving in the "outward" direction, the wind flows into the U while, when the rotor blade is moving in the "reverse" direction, it curves and curves the Us on the rotor blade should be conducted over. However, since only the profile, but not the surface opposite the wind changes, the efficiency of such rotor blades and rotors equipped with them is not optimal.

In another alternative, the so-called Darrieus rotor, the rotor blades in the form of airfoils, as known from the aircraft, designed. These rotor blades always have a torque on the shaft when they are not parallel or antiparallel to the wind direction. However, this torque is relatively small, so that the efficiency of these rotors is not optimal.

The invention is therefore the object of proposing a wind turbine that uses the advantages of vertical axis wind turbines and ensures better utilization of wind energy.

The invention solves this problem by a generic wind power plant, which is characterized in that at least one rotor blade associated with the control arm is attached to each rotor blade, and from each rotor blade at least one control arm is attached to a common connecting element, in one of the Rota Positioning axis offset control position is arranged so that an angle between the rotor blade and the at least one rotor arm associated therewith changes during a rotation of the rotor about the axis of rotation. The rotor blades thus perform a pivoting movement relative to the rotor arm assigned to them during a rotation about the rotation axis.

At least one control arm of each rotor blade is arranged on the common connection element. The pivoting movements of the individual rotor blades relative to the rotor arms are therefore only possible together for all rotor blades.

It has proven to be advantageous if the individual rotor arms, by means of which the rotor blades are fastened to the shaft, are all of the same length. This means that the connection points at which the rotor blades are attached to the rotor arms, all revolve on the same circular path when revolving around the axis of rotation. Now, if the control arms, which are arranged on the common connecting element, the same length formed for each rotor blade, the points move on a common circular path, where the control arms are arranged on the respective rotor blade. The fact that on the one hand, however, the control arms need not be formed as long as the rotor arms and the other the common connecting element is not in an extension of the axis of rotation, these pivot points move on a different circular path than the points at which the rotor blade attached to each associated rotor arm. By how much and in which direction these two circular paths are shifted from one another, depends on the control position of the common connecting element. The size ratios of the two circular paths correspond to the size ratio of the length of the rotor arm to that of the control arm of each rotor blade.

In contrast to wind turbines, which have a rotor with a horizontal axis of rotation and therefore need to track a rotating wind direction, this is unnecessary in conventional vertical axis wind turbines. The flow of the wind turbine through the wind is usually independent of the wind direction in these systems, since the axis of rotation is in the optimum case perpendicular to the wind direction, namely vertical. However, according to the invention be achieved by the pivotal movement of the rotor blades in a revolution about the axis of rotation, that during the "return direction", ie the movement against the wind direction, a maximum torque is transmitted to the shaft, because here the wind speed adds up with the rotor blade speed the same physical effect as in a sailboat with a sailsail, which is on the windward course, that is opposite to the wind direction If the rotor blade and the wind have the same speed but in opposite directions, the laws of physics result from the doubling of the relative speed Sailboats, and especially ice sailors, can reach speeds well above ten times the wind speed, which is eight times that of the airfoil on the rotor blade.

It has therefore been found to be advantageous if the control position is adjustable by a wind occurring on the wind turbine. In this way, a complicated possibly electronic control, which controls the control position of the common connecting element and optionally readjust a rotating wind direction, unnecessary.

If the wind hits a suitably equipped wind power plant whose rotor blades are in any position, it exerts a force on all rotor blades of the wind turbine, which are transmitted via the control arms to the common connecting element. As a result, the common connecting element is brought into a position set by the wind.

It has proven to be advantageous if the connecting element is arranged on a closed path, for example a circular path, movable about the axis of rotation of the rotor. A wind impinging on the wind turbine shifts the common connecting element, by the force applied to the rotor blades, transmitted via the control arms to the position on the closed track which lies downstream of the axis of rotation of the rotor. In this position, the common connecting element also remains during the rotation of the rotor, until the wind direction changes and it by the now from another The direction of the blowing wind is brought into a different control position. The pivotal movements performed during one revolution about the axis of rotation of the individual rotor blades relative to the respectively associated rotor arm pivoting movements can be designed to different degrees. This can be adjusted, for example, by the length of the control rods, as well as the distance of the control position from the extension of the axis of rotation and the distance of the points at which a rotor arm and a control arm are arranged on a rotor blade. Advantageously, the rotor arms and the control arms are dimensioned and fixed to the rotor blades such that the rotor blades are perpendicular to the rotor arm assigned to them at a control position set by the wind, when they move in a rotation around the axis of rotation against a wind direction of the wind. In this way it is ensured that at a set by the wind control position, the rotor blades have the minimum flow resistance and maximum power coefficient when they move against the wind direction, ie in the "back direction".

The rotor blades advantageously have their greatest extent along a longitudinal direction, the longitudinal direction extending along the shaft. This is the case, for example, with vertical axis wind turbines. The fact that the different flow resistance, the rotor blades during movement in the "direction" and "return direction" have, are no longer caused by the profile of the rotor blades, but by the changing angle of attack, it is possible, the rotor blades completely without profile, so for example in the form of flat surfaces, such as plates or boards to design. As a result, not only is the calculation of complicated fluid mechanical processes superfluous, but also the production and production of such rotor blades is significantly simplified and less expensive.

The fact that the rotor blades extend along the shaft of the rotor, it comes not to the extreme speed differences at different points of a rotor blade, as they occur in conventional wind turbines with horizontal axes of rotation. Therefore, at least the size and length of the rotor blades are no limits. It is thus possible to include a description here as well. bene wind turbine with rotor blades, for example, longer than 50 meters, preferably longer than 75 meters, more preferably longer than 100 meters. In such large wind turbines, the individual components, so for example a mast on which the wind turbine is mounted, and the rotor with the rotor blades on an immense weight. In the case of the wind power plant described here, however, there is the advantage that, in the optimum case, the axis of rotation runs perpendicular to the wind direction, that is to say vertically, for example. As a result, the immense weight of a large wind turbine can be derived and intercepted particularly easily and reliably. In such large wind turbines, the effect may occur that the wind speed in the lower region of the rotor blades is different than in the upper region. In particular, higher wind speeds are to be expected in the upper region of the rotor blades, as they occur in the lower region of the rotor blades, ie near the ground. For this case, it may be advantageous if the rotor blades along the longitudinal direction at an angle with the shaft, which is not equal to zero degrees. In particular, the distance between the rotor blades and the shaft of the rotor should increase towards the top, so that the rotor blades in the upper region have to travel a longer distance in one revolution around the axis of rotation than in the lower region. As a result, they must have a slightly higher speed than the lower areas of the rotor blades, so that the larger wind speeds occurring in this area can be used much better. It has proven to be particularly advantageous if the wind power plant comprises a setting device with which this angle can be set. In this way, different weather conditions with different wind speed profiles can be taken into account.

In particular, with such large rotor blades, it is advantageous if each rotor blade at least two rotor arms and / or at least two control arms are assigned, which are arranged offset along the longitudinal direction of the rotor blades. Thus, it is conceivable, for example, to connect particularly long rotor blades not only at one point to the shaft, but to provide two connecting elements, that is to say two rotor arms, with which each rotor blade is fastened to the shaft. These are advantageously arranged offset along the shaft. The same applies to several control arms. Again, it may be beneficial to have more than one control arm for each rotor provide leaf, which has an increased stability of the wind turbine result. Since the pivoting movement of the rotor blades is transmitted by the control arms on each revolution about the axis of rotation, a plurality of over the longitudinal direction of the rotor blades distributed control arms should be provided for each rotor blade from a certain length.

Alternatively or additionally, the wind turbine can also have two rotors, which have mutually opposite directions of rotation. These can be arranged, for example, next to one another along the direction of rotation, that is, for example, when the wind power installation is set up above one another. The fact that the two rotors have different directions of rotation, on the one hand, the torques occurring can be mutually compensated, and on the other hand, the relative speeds of different components of a generator arranged in the wind turbine are doubled to each other.

In a particularly preferred embodiment, the wind turbine is equipped with a float that is shaped and dimensioned so that the rotor is completely above a water surface when the wind turbine floats with the float in the water. Especially with a vertical orientation of the axis of rotation and the rotor caused by the possible high rotational speeds centrifugal forces that prevent tilting or even tipping over of the wind turbine even with strong winds. Such a wind turbine would therefore not be fixed at a foundation on the seabed when used at sea as an offshore wind turbine. It is sufficient, for example via an anchor or a similar device, to prevent the wind turbine from floating with its float leaving its position. This has many advantages. The field of application of offshore wind turbines is limited on the one hand by the maximum depth of the sea, in which foundations can be laid. With the embodiment of a wind turbine described here, this limitation would be overcome because no foundations would have to be laid. In addition, particularly at sea sometimes very large wind speeds are found in which conventional wind turbines with a horizontal axis of rotation due to the problem described can not be used. The wind turbines described here are be used effectively and efficiently up to significantly higher wind speeds, so that the energy yield of offshore wind turbines can be significantly improved by the embodiment described here. If, after positioning a wind turbine, it turns out that the chosen location was not optimal, a wind turbine fitted with a float can simply be towed to another location or, if equipped with engine power, can independently travel to that other location. This is just like the dismantling of a corresponding wind turbine without the polluting residues and without a large construction and decommissioning costs possible.

Particularly simple is the design of a wind turbine when the float is a ring or circular pontoon, which also serves as a mast to support the rotor axis and the rotor.

If, in particular at high wind speeds, the rotational speed of the rotor becomes too great even for the embodiment of a wind turbine described here, the energy can be temporarily stored, for example, in weights which are set in rotation. If the wind speed decreases later, this rotation of the weights can be converted back into a rotation of the rotor of the wind turbine, whereby an equalization of the rotor speed of the wind turbine is achieved.

In principle, wind turbines described here can be equipped with any number of wings. However, they preferably have, between 3 and 8, in particular 4 rotor blades.

With the aid of a drawing, an embodiment of the present invention will be explained in more detail below. It shows:

Figure 1 - a schematic plan view of a wind turbine according to a first embodiment of the present, and

Figure 2 - a schematic side view of a wind turbine according to another embodiment of the present invention.

Figure 1 shows the schematic plan view of a wind turbine according to a first embodiment of the present invention along an axis of rotation. Centrally located is a shaft 2 of a rotor on which four rotor arms 4 are arranged. In the illustrated embodiment, the rotor arms 4 are arranged offset by 90 °. At each radially outer end of the rotor arms 4 is a first pivot point 6, on each of which a rotor blade 8 is arranged. The rotor blades 8 are pivotally mounted on the associated rotor arm 4 in the first pivot point 6.

The first articulation points 6 of each rotor blade 8 move on a rotor circle line 10 represented by a dashed line whose radius corresponds to the length of the rotor arm 4.

At each one end of the rotor blade 8 is in the embodiment shown in Figure 1, a second pivot point 12. At this a control arm 14 is connected to the rotor blade 8, whose end facing away from the rotor blade 8 is arranged on a common connecting element 16. This is movable on a circular path 18 shown schematically and is located in the embodiment shown in Figure 1 in a control position. The second pivot points 12 of each rotor blade 8 move on a control circuit line 20 shown by semicolons whose radius corresponds to the length of the control arms 14. In the embodiment shown in Figure 1, the length of the control arms 14 is equal to the length of the rotor arms 4, so that the control circuit 20 is exactly as large as the rotor circuit line 10. They are only offset by the radius of the circular path 18 against each other. The situation shown in Figure 1 arises when wind from the direction indicated by the arrow 22 hits the wind turbine. It can be seen that the control position, in which the common connecting element 16 is located, is shifted in the wind direction represented by the arrows 22 with respect to the shaft 2. This is due to the fact that the wind exerts a force on the four rotor blades 8, which leads to the displacement of the common connecting element 16 along the circular path 18. The direction of rotation of the wind turbine shown in Figure 1 is counterclockwise. It can be seen that only the rotor blade 8 shown on the right in FIG. 1 is aligned parallel to the wind direction represented by the arrows 22. It moves upwards in a direction of rotation counterclockwise and thus in the so-called "return direction." In this position, the special design of the wind power plant shown in FIG. 1 ensures that the rotor blade is held in the position in which it has a minimum flow resistance.

The size of the pivoting movement, which performs a rotor blade 8 in one revolution about the shaft 2, is determined by a plurality of sizes. These include the radius of the circular path 18, the length of the control arms 14 and the distance between the first pivot points 6 and the second pivot points 12. An increase in the distance between the first pivot points 6 and the second pivot points 12 has as well as an increase in the radius the circular path 18 and a shortening of the length of the control arms 14 an increase in the angular deflection during the pivotal movement of the rotor blades 8 result.

In Figure 1 it can be seen clearly that the three remaining rotor blades 8 exert a torque on the shaft 2 by the wind occurring along the arrows 22 that is directed for all three rotor blades 8 in the same direction. Thus, all the rotor blades 8 except for the rotor blade 8, which moves in the "reverse direction", ensure the transmission of torque and thus the driving of a generator.

Figure 2 shows a schematic side view of a wind turbine according to another embodiment of the present invention. It comprises a mast 24, on which two rotors 26 are arranged, each of which has rotor blades 8, rotor arms 4 and control arms 14. The control arms 14 are with the common Connecting element 16 connected. Between the two rotors 26, a generator 28 is arranged on the mast 24, in which simultaneously the shaft 2 and the axis of rotation of the rotors 26 extends. It is advantageous if the two rotors 26 have different directions of rotation, so that the generator 28 is driven at twice the speed. In addition, in this case, the torques that are caused by the rotors 26, balanced.

In the embodiment shown in Figure 2 it can be clearly seen that the rotor blades 8 include an angle with the mast 24 and the shaft 2, which is not equal to zero degrees. In particular, an upper end 30 of the rotor blades 8 of the upper rotor 26 is significantly further away from the shaft 2, as a lower end 32 of the rotor blades 8 of the lower rotor 26. In this way, different wind speeds, which can prevail at different heights bill be worn. It should be noted that in particular the longitudinal extent of the rotor blades 8 in FIG. 2 is shown clearly shortened. The rotor blades 8 of the two rotors 26 are advantageously at least 20, more preferably at least 50 or even at least 100 meters long.

In the lower region of the mast, an adjusting device 34 is schematically indicated, by which the angle between the rotor blades 8 and the mast 24 or the shaft 2 is adjustable.

LIST OF REFERENCE NUMBERS

2 wave

4 rotor arm

6 First point of articulation

8 rotor blade

10 rotor circle line

12 second articulation point

14 control arm

16 common connection element

18 circular path

20 control circuit line

22 arrow

24 mast

26 rotor

28 generator

30 Upper end

32 Lower end

34 adjustment device

Claims

claims:

1st wind turbine with

a rotor 26, the

a wave (2) and

a plurality of rotor blades (8) and comprises

is rotatable about an axis of rotation,

wherein each rotor blade (8) is attached to the shaft (2) via at least one rotor arm (4) associated with the rotor blade (8),

characterized in that

at least one control arm (14) associated with the rotor blade (8) is fastened to each rotor blade (8) and

at least one control arm (14) of each rotor blade (8) is fastened to a common connecting element (16) arranged in a control position offset from the axis of rotation, so that an angle between each rotor blade (8) and at least one associated therewith Rotor arm (4) changed during a rotation of the rotor (26) about the axis of rotation.

2. Wind turbine according to claim 1, characterized in that the control position is adjustable by a wind incident on the wind turbine.

3. Wind turbine according to claim 1 or 2, characterized in that the common connecting element (16) on a closed path (18) is arranged to be movable about the axis of rotation.

4. Wind turbine according to one of the preceding claims, characterized in that the rotor arms (4) and the control arms (14) are dimensioned and secured to the rotor blades (8), that the rotor blades (8) at a control position set by the wind vertically on the rotor arm (14) assigned to you, when it moves on a revolution around the axis of rotation against a wind direction of the wind.

5. Wind turbine according to one of the preceding claims, characterized in that the rotor blades (8) have a maximum extent in a longitudinal direction which extends along the shaft (2).

6. Wind turbine according to claim 5, characterized in that the rotor blades (8) along the longitudinal direction at an angle with the shaft (2), which is not equal to zero degrees.

7. Wind turbine according to claim 6, characterized in that the wind turbine comprises an adjusting device (34), with which the angle is adjustable.

8. Wind turbine according to one of the preceding claims, characterized in that the rotor blade (8) at least two rotor arms (4) and / or at least two control arms (14) are associated, which are arranged offset along the longitudinal direction of the rotor blades (8).

9. Wind power plant according to one of the preceding claims, characterized in that the wind turbine has two rotors (26) which have mutually opposite directions of rotation.

10. Wind turbine according to one of the preceding claims, characterized in that the wind turbine is equipped with a floating body which is shaped and dimensioned such that the rotor (26) is completely above a water surface when the wind turbine floats in the water.