DE20205073U1 - Wind turbine with counter-rotating impellers - Google Patents

Description

Hubert Roth March 30, 2002

Wind turbine with counter-rotating impellers

The present invention relates to wind turbines according to the preamble of claim 1.

On the one hand, there are wind turbines whose wind turbines have a horizontal axis. However, such wind turbines have various disadvantages. For example, they often cannot withstand gusts of wind, which can cause the turbines to tip over. Therefore, in very strong winds, such wind turbines have to be partially turned out of the wind to avoid damage, which results in less than optimal power output. In addition, these turbines impair residential use in their vicinity, as they generate considerable noise and the shadows cast by their rotating wind turbines lead to the annoying "disco effect".

On the other hand, wind turbines are known whose wind turbines rotate around a vertical axis. Such wind turbines are less disruptive to residential use in their vicinity. In addition, in an arrangement with several such turbines, they can be placed relatively close to one another, so that the overall space requirement is reduced. However, the energy yield of such turbines needs to be improved.

It is an object of the present invention to further develop wind turbines whose wind turbines rotate about a vertical axis in such a way that they have increased stability, in particular against gusts of wind, and that at the same time the energy yield is improved, in particular in hilly areas with less wind.

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This object is achieved by a wind turbine according to claim 1. The dependent claims relate to advantageous embodiments of the invention.

The present invention is explained in more detail below using preferred embodiments with reference to the accompanying drawings.

Fig. 1 shows the front view of an embodiment of a wind turbine according to the present invention;

Fig. 2 shows a plan view of an impeller according to an embodiment of the present invention;

Fig. 3 shows the front view of another embodiment of a wind turbine according to the present invention;

Fig. 4 shows a plan view of an impeller according to another embodiment of the present invention;

Fig. 5 shows a schematic representation of how the rotor blades can be adjusted according to an embodiment of the invention depending on their angular position;

Fig. 6 shows a schematic representation of a cross section through a generator according to an embodiment of the invention;

Fig. 7 shows a schematic representation of a cross section through a generator according to a further embodiment of the invention; and
Fig. 8 shows a schematic representation of a longitudinal section through a generator according to yet another embodiment of the invention.
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Fig. 1 shows a front view and a top view of an embodiment of a wind turbine 1 according to the present invention. The wind turbine has first impellers 2 and a second impeller 3, wherein the first impellers 2 rotate counterclockwise when viewed from above, and the second impellers 3 rotate clockwise when viewed from above.

rotate. The first wheels 2 are combined in a first wheel group 4, and the second wheels 3 in a second wheel group 5, wherein the wheels in their associated wheel group are preferably coupled to one another.
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In the embodiment shown in Fig. 1, the impeller groups 4, 5 are mounted on a tower 6, and a generator 7 is arranged between the impeller groups 4, 5. However, this arrangement is not mandatory. The impellers can also be mounted directly on a building, and the generator can also be located below the impeller groups 4, 5.

The opposite direction of rotation of the first and second impeller groups 4, 5 ensures optimal stabilization of the wind turbine through a doubled gyroscopic effect. Since the wind turbine is kinematically stabilized against a change in the angle of the axis of rotation by this gyroscopic effect, it is also more resistant to the strongest gusts of wind. The load-bearing parts, in particular the tower and the foundation, can therefore be made weaker.

Fig. 2 shows a top view of a first impeller 2 according to the embodiment shown in Fig. 1. It can be seen that the blades adjust depending on their angular position. This ensures that the blades have a high air resistance when they move with the wind and a low air resistance when they move against the wind, resulting in an increased yield of wind energy.

The blades can be adjusted using a lever attached to the blade in question, which is guided at its end in a guide rail, whereby this guide rail has the shape of a sinusoidal curve around its circumference, so that a cam-like adjustment is achieved. The guide rail for adjusting the blades can be moved during the

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During operation of the system, for example, an electric motor, a gear and a gear ring attached to the guide rail can be rotated around the axis of the impellers so that adjustment to the wind direction can take place. In addition, in the event of a fault, the blades can be adjusted in such a way that they do not produce a driving effect but rather a braking effect, in order to ensure that the wind turbine can be shut down more quickly together with a braking system.

According to the present invention, the blades of adjacent impellers of the same impeller group are preferably adjusted in such a way that, when they move with the wind, they together form a widely fanned V in cross-section in the case of straight blades, as is also shown schematically in Fig. 5 (position of the blades on the right-hand side in Fig. 5), or a circular segment or a hemisphere in the case of curved blades.

This ensures that adjacent blades have an optimal air resistance together in the angle position in which they are most exposed to the wind (right position in Fig. 5). Depending on the wind strength, the angle of the basic blade position can also be smaller in order to allow the following wind to take effect and thus prevent wind build-up on the blades.

It is particularly advantageous to maintain a wind passage opening or an air gap between the blades when the blades are "closed" (right position in Fig. 5) in order to optimize air resistance. This air gap can be adjusted mechanically or hydraulically using a control system even while the wind turbine is in operation in order to ensure optimal adjustment when wind strengths change. Spacers can also be provided between the blades.

As the angle progresses, the position of the wings becomes flatter (as in the middle position in Fig. 5, but there with the blades closing), so that

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the wind can flow even more through the pairs of wings. This creates a suction effect at the edges of the wings when the wind breaks away (updraft forces). Finally, the wings are positioned completely flat during the return movement (see left position in Fig. 5) in order to have the lowest possible air resistance.

This measure increases the yield of wind energy. This is because the ratio of air resistance between the almost "closed" blades on the side where the blades move with the wind and the "open" blades on the side where the blades move against the wind is increased, so that the "closed" blades are driven more strongly, but the "open" blades are slowed down less.

Fig. 3 shows the front view of another embodiment of a wind turbine according to the present invention. In this embodiment, two first and two second impeller groups 4, 5 are provided alternately. In addition, this embodiment has first and second wind deflection devices 8, 9 on the sides of the impellers on which the blades move against the wind direction, which deflect the wind flowing in their area in a direction parallel to the axis towards an area of the adjacent impeller group in which the blades move with the wind direction.

This ensures that the wind, which would have a decelerating effect on one group of impellers without a wind deflection device, is deflected in such a way that it further increases the incoming, driving wind on an adjacent group of impellers, ideally even doubling it.

Furthermore, the impellers can be surrounded by a protective plate in the area where the blades move against the wind, as in

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Fig. 4, in order to avoid the braking effect of the oncoming wind. Such a protective plate can be formed in one piece together with an associated wind deflector.

The wind deflectors or protective plates can also be rotated around the axis of the system by an actuating mechanism in order to correspond to a change in wind direction or to achieve a braking effect in the event of a malfunction.

The wind turbine according to the present invention can have one or more generators 7 which are driven by the first and second impeller groups. Synchronous, asynchronous or ring generators of conventional design can be used. Preferably, however, generators according to the invention are used, which are described below.

Fig. 6 shows a schematic representation of a cross section through a generator according to the invention for a wind turbine according to the present invention. This generator comprises an inner rotor 11 and an outer rotor 10, the outer rotor 10 being driven by the first impeller group 4 and the inner rotor 11 being driven by the second impeller group 5.

Either the inner or the outer rotor can be designed as a stator in the electrical engineering sense, with the special feature that the stator is not stationary but is also driven and therefore also rotates. The other rotor, e.g. the inner rotor if the outer rotor is designed as a stator, is supplied with power via slip rings in order to supply electromagnets arranged on the inner rotor with an excitation current. Slip rings, in particular with plasma conductors, are also provided for the rotating stator in order to be able to discharge the current generated.

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The advantage of this arrangement is the higher relative rotational speed between stator and rotor. This immediately generates an alternating current frequency that is in the range of the mains frequency, making it easier to convert it to the appropriate mains frequency for feeding into the power grid. This means that a transmission gear is not required. Conventional conversion via a direct current intermediate circuit into feed-in alternating current can also be provided, e.g. a regulated pulse width inverter.

However, due to different moments of inertia, one impeller group can accelerate faster than the other, and if the wind speeds are different at the height of the first or second impeller group, the driving force can be undesirably different. Therefore, an opposite coupling between the impeller groups for a generator, e.g. via a non-translating gear, is useful in order to ensure the same absolute rotational speeds of the impeller groups, and thus of the stator and the rotor.

A further advantage of the generator arrangement shown in Fig. 6 is that the statically favorable gyroscopic effect is further enhanced by increasing the rotating masses.

Fig. 7 shows a schematic representation of a cross section through another generator according to the invention for a wind turbine according to the present invention. This generator has a stator 14, an inner rotor 13 and an outer rotor 12, with the stator being arranged between the inner and outer rotors. There are three sub-variants:

According to the first sub-variant, the stator iron cores and their windings are continuous and uniform for the inner and outer stator area. Frequency doubling can be achieved by coupling the inner and outer rotor in such a way that an outer

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rotor winding with a north pole passes, then an inner rotor winding with a north pole, then an outer rotor winding with a south pole, and finally an inner rotor winding with a south pole.

According to a second sub-variant, the stator iron cores for the inner rotor and the outer rotor can be separate, whereby the corresponding stator winding is continuous over the entire corresponding stator iron core, but with a changed winding direction in the outer region of the stator compared to the inner region of the stator.

According to a third variant, the stator can be completely separated between its inner and outer areas in terms of its cores and windings. However, this generates two separate currents that must then be coupled again.

As an alternative to the embodiment shown in Fig. 7, including the sub-variants described above, the stator can also be U-shaped from the outside to the inside in a cross section along the axis of the impellers, so that two counter-rotating rotors can be arranged in the space between them. This means that the magnetization reactive power for the rotors is generated by the counter-rotating rotors themselves, or that an additional current yield is achieved, which can be taken up via the slip rings of the rotors.

However, for the generator shown in Fig. 7, the direction of rotation for a rotor can also be reversed via a non-translating reversing gear if a separation of the iron cores and/or the windings of the rotor is undesirable in the above second and third sub-variants.

Fig. 8 shows a schematic representation of a cross section through yet another generator according to the invention for a wind turbine according to the present invention. In this generator, the two rotors 15, 16

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for the first and second impeller groups respectively, are constructed in a disc shape, wherein two connected stators 17, 18 are provided which are arranged above and below the rotors respectively.

In this case, increasing the moments of inertia of the first and second impeller groups is advantageous in order to better withstand gusts of wind due to the gyroscopic effect. In addition, the reactive magnetization power for the rotors is generated by the counter-rotation of the rotors themselves, or that an additional current yield is achieved, which can be taken up via the rotors' slip rings.

List of reference symbols: Wind turbine 1 first wheels 2 second wheels 3 first wheel group 4 second wheel group 5 Tower 6 generator 7 first wind deflectors 8th second wind deflectors 9 outer rotor 10 inner rotor 11 outer rotor 12 inner rotor 13 stator 14 Rotor for the first wheel group 15 Rotor for the second wheel group 16 Stator for the first wheel group 17 Stator for the second wheel group 18

Claims (32)

1. Wind turbine with two or more impellers which rotate about an axis substantially perpendicular to the wind direction during operation of the wind turbine, the impellers having blades, characterized in that the impellers comprise one or more first impellers which rotate in a first direction of rotation due to the wind flow, and that the impellers comprise one or more second impellers which rotate in a second direction of rotation due to the wind flow, which is opposite to the first direction of rotation. 2. Wind turbine according to claim 1, characterized in that the first impellers are divided into one or more first impeller groups, and the second impellers are divided into one or more second impeller groups, wherein the first impeller groups are arranged along the axis alternately with the second impeller groups. 3. Wind turbine according to claim 1 or 2, characterized in that for each first impeller group on the side facing the wind in the area in which the blades of the first impellers move against the wind direction during operation of the wind turbine, a first wind deflection device is provided which deflects the wind flowing in its area in a direction parallel to the axis. 4. Wind turbine according to claim 3, characterized in that each first wind deflection device deflects the wind flowing in its area in such a way that it is fed to an adjacent second impeller group in a region in which the blades of the second impellers move with the wind direction during operation of the wind turbine. 5. Wind turbine according to one of the preceding claims, characterized in that for each second impeller group on the side facing the wind in the area in which the blades of the second impellers move against the wind direction during operation of the wind turbine, a second wind deflection device is provided which deflects the wind flowing in its area in a direction parallel to the axis. 6. Wind turbine according to claim 5, characterized in that every second wind deflection device deflects the wind flowing in its area in such a way that it is fed to an adjacent first impeller group in an area in which the blades of the first impellers move with the wind direction during operation of the wind turbine. 7. Wind turbine according to one of claims 3 to 6, characterized in that a mechanism is provided for rotating the wind deflectors about the impellers. 8. Wind turbine according to one of claims 3 to 7, characterized in that a mechanism is provided for adjusting the wind deflection devices such that the wind is deflected more or less strongly in the direction parallel to the axis. 9. Wind turbine according to one of the preceding claims, characterized in that a protective plate is provided for each first and second impeller group, which surrounds the blades of the respective impeller group at least in part of the angular range in which the blades move against the wind direction during operation of the wind turbine. 10. Wind turbine according to claim 9, characterized in that each protective plate completely encloses the blades of the respective impeller group in the radial direction, in particular up to immediately in front of their axis. 11. Wind turbine according to claim 9 or 10, characterized in that each protective plate is circular segment-like in a view perpendicular to the axis, and in particular covers an angular range of 90° to 180°. 12. Wind power plant according to one of claims 9 to 11, characterized in that the protective plates and the wind deflection devices for the respective impeller groups are each formed in one piece. 13. Wind turbine according to one of claims 3 to 6, characterized in that a mechanism is provided for rotating the protective plates around the impellers. 14. Wind turbine according to one of the preceding claims, characterized in that the wind turbine comprises one or more two- or multi-pole electric generators driven by the first and second impeller groups. 15. Wind turbine according to claim 14, characterized in that the electric generator or generators each comprise an inner rotor and an outer rotor, wherein the inner rotor is driven by one or more of the first impeller groups, and wherein the outer rotor is driven by one or more of the second impeller groups. 16. Wind turbine according to claim 14 or 15, characterized in that either the inner rotor or the outer rotor is designed as a stator, so that the stator also rotates with the first or second impeller group. 17. Wind turbine according to claim 15 or 16, characterized in that there is only a small radial gap between the inner and the outer rotor of the electric generator or generators, wherein the current to be generated during operation of the wind turbine is generated in electric coils either in the inner or in the outer rotor. 18. Wind power plant according to claim 15, characterized in that between the inner and the outer rotor of the electric generator or the respective electric generators there is a fixed stator in which electricity is generated by the rotary movement of the inner rotor and the counter-rotating movement of the outer rotor during operation of the wind power plant. 19. Wind turbine according to one of claims 14 to 19, characterized in that the generator or the respective generators each comprise two disc-shaped rotors and two disc-shaped connected stators, wherein the rotors have approximately the same dimensions and are directly adjacent to one another, and wherein the stators are arranged above or below the rotors. 20. Wind turbine according to one of claims 15 to 19, characterized in that the inner rotors comprise electric coils, electromagnets and/or permanent magnets, and that the outer rotors comprise electric coils, electromagnets and/or permanent magnets. 21. Wind turbine according to one of claims 14 to 20, characterized in that each electric generator is driven by a first impeller group and a second impeller group. 22. Wind turbine according to one of claims 14 to 21, characterized in that the electric generator is a synchronous, asynchronous, ring or disk generator. 23. Wind turbine according to one of the preceding claims, characterized in that the blades of the impellers are each adjustable depending on their angular position during rotation such that the blades have a high air resistance when they move with the wind direction during operation of the wind turbine, and such that the blades have a low air resistance when they move against the wind direction during operation of the wind turbine. 24. Wind turbine according to one of the preceding claims, characterized in that adjacent impellers of the same impeller group are adjustable in such a way that, when they move with the wind, they together form a widely fanned V in cross-section in the case of straight blades, or a circular segment or a hemisphere in the case of curved blades, whereby an air gap remains between adjacent blades. 25. Wind turbine according to claim 24, characterized in that the air gap remaining between adjacent blades is adjustable, in particular during operation of the wind turbine. 26. Wind power plant according to one of claims 1 to 23, characterized in that adjacent impellers of the same impeller group are adjustable in such a way that, when they move with the wind, they together form a widely fanned V in cross-section in the case of straight blades, or a circular segment or a hemisphere in the case of curved blades, with the edges of adjacent blades lying directly against one another. 27. Wind turbine according to one of the preceding claims, characterized in that the blades can be adjusted in such a way that they can produce a braking effect in the event of a fault. 28. Wind turbine according to one of the preceding claims, characterized in that the first and second impellers have the same axis. 29. Wind turbine according to one of the preceding claims, characterized in that the wind turbine comprises a tower on which the rotors are mounted. 30. Wind turbine according to one of the preceding claims, characterized in that the wind turbine comprises a house or a building on the roof of which the rotors are mounted. 31. Wind turbine according to one of the preceding claims, characterized in that each first impeller group comprises one, two, three or more first impellers, and that each second impeller group comprises one, two, three or more second impellers. 32. Wind turbine according to one of the preceding claims, characterized in that a computer control is provided, in particular for controlling the mechanism for adjusting the blades, the mechanism for adjusting the angular position of the wind deflection devices or the protective plates and/or the mechanism for adjusting the strength of the wind deflection by the wind deflection devices.