Oscillating damper for damping tower harmonics

Abstract

An oscillation damper may comprise a suspension having a suspension length. The oscillation damper may comprise a pendulum which may be suspended by the suspension and may have a pendulum mass. The pendulum may comprise a fixed part which may have a side face. The pendulum may comprise a slideable part for collision with a movement limiter. The slideable part may be a substantial portion of the pendulum mass. The slideable part may comprise one or more stacked plates which may be positioned on the fixed part, and the one or more plates may extend beyond the side face. The oscillation damper may comprise a movement limiter. The movement limiter may face the pendulum.

Claims

1. A tower having at least one harmonic frequency, the tower comprising at least one oscillation damper for damping the at least one harmonic frequency wherein the at least one oscillation damper includes a suspension having a suspension length that is 10-50% longer than a length of the at least one harmonic frequency to be damped; a pendulum suspended by the suspension, the pendulum including a pendulum mass, and a fixed part having a planar side face and a planar upper face; a movement limiter facing the pendulum; and wherein the pendulum further includes a slideable part positioned on the planar upper face, the slideable part and the planar side face configured and arranged for collision with the movement limiter, the slideable part being a substantial portion of the pendulum mass and including one or more stacked plates positioned on the planar upper face of the fixed part and extending beyond the planar side face, wherein the one or more stacked plates are displaceable relative to the planar upper face.

2. The tower according to claim 1, characterised in that the one or more stacked plates are stacked with gradually larger horizontal extent.

3. The tower according to claim 1, characterised in that the one or more stacked plates constitute 20% to 90% of the pendulum mass.

4. The tower according to claim 1, characterised in that the fixed part includes a top part and a bottom part, the bottom part connected to the top part, and wherein the one or more stacked plates are positioned on the bottom part.

5. The tower according to claim 1 characterised in that the at least one oscillation damper is positioned at a top-tower section, the at least one oscillation damper is configured and arranged for damping a first harmonic frequency of the tower.

6. The tower according to claim 5, characterised in that the at least one oscillation damper is configured and arranged for damping a second harmonic frequency of the tower and is positioned near a second harmonic oscillation of the tower.

7. The tower according to claim 1, wherein the tower is a wind turbine tower.

8. The tower according to claim 1, wherein the one or more stacked plates constitute 20% to 60% of the pendulum mass.

9. The tower according to claim 1, wherein the one or more stacked plates constitute 20% to 40% of the pendulum mass.

10. A tower having at least two harmonic frequencies, the tower comprising at least one oscillation damper configured and arranged for damping the second harmonic frequency of the tower, and is positioned near a second harmonic oscillation of the tower, the at least one oscillation damper includes a suspension having a suspension length; a pendulum suspended by the suspension, the pendulum including a pendulum mass, and a fixed part having a planar side face and a planar upper face; a movement limiter facing the pendulum; and wherein the pendulum further includes a slideable part positioned on the planar upper face, the slideable part and the planar side face configured and arranged for collision with the movement limiter, the slideable part being a substantial portion of the pendulum mass and including one or more stacked plates positioned on the planar upper face of the fixed part and extending beyond the planar side face, wherein the stacked plates are displaceable relative to the upper face.

11. The tower according to claim 10, characterised in that the one or more stacked plates are stacked with gradually larger horizontal extent.

12. The tower according to claim 10, characterised in that the one or more stacked plates constitute 20% to 90% of the pendulum mass.

13. The tower according to claim 10, characterised in that the fixed part includes a top part and a bottom part connected to the top part, and wherein the one or more stacked plates are positioned on the bottom part.

Description

DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a wind turbine tower with an oscillation damper in the tower.

(2) FIG. 2 shows a tower section with an oscillation damper disposed at the top of the tower section.

(3) FIG. 3 is a sectional view of an embodiment of an oscillation damper where the pendulum is suspended in one suspension.

(4) FIG. 4 is a sectional view of an embodiment of an oscillation damper where the pendulum is suspended in three suspensions.

(5) FIG. 5 shows a sectional view of another embodiment of an oscillation damper where the pendulum is suspended in one suspension.

(6) FIG. 6 shows a sectional view of another embodiment of an oscillation damper where the pendulum is suspended in three suspensions.

(7) TABLE-US-00001 Movement limiter 1 Suspension 2 Fixed part 3 Plates 4 Oscillation damper 5 Wind turbine tower 6 Tower flange 7 Platform 8 Tower section 9 Pendulum 10 Side face 11 Slideable part 14 Tower 15

DETAILED DESCRIPTION OF THE INVENTION

(8) FIG. 1 discloses a wind turbine tower 6, 15 with an oscillation damper 5 in the tower 6, 15. The oscillation damper 5 is positioned at a top-tower section 9 for damping the first harmonic of the wind turbine tower 6, 15.

(9) FIG. 2 shows a tower section 9 with an oscillation damper 5 disposed at the top of a tower section 9. The oscillation damper 5 is positioned near a platform 8, such that the oscillation damper 5 can be serviced. The tower section 9 has a tower flange 7 near the top.

(10) This tower section 9 may be the top part of a wind turbine tower 6, thus the oscillation damper 5 will be adapted to dampen a first harmonic of the wind turbine tower 6.

(11) This tower section 9 may be an upper middle part of a wind turbine tower 6, thus the oscillation damper 5 will be adapted to dampen a second harmonic of the wind turbine tower 6.

(12) FIG. 3 is a sectional view of an embodiment of an oscillation damper 5 where the pendulum 10 is suspended in one suspension 2.

(13) The oscillation damper 5 comprises a suspension 2 having a suspension length. The suspension length determines the frequency which is to be dampened.

(14) The oscillation damper 5 comprises a pendulum 10 suspended by the suspension 2. The pendulum 10 has a pendulum mass. The pendulum 10 comprises a fixed part 3 having a side face 11 and a slideable part 14.

(15) The slideable part 14 is a substantial portion of the pendulum mass such as 20-90%, 20-60% or 20% to 40% of the pendulum mass. The slideable part 14 comprises one or more stacked plates 4 which are positioned on the fixed part 3 and extend beyond the side face 11.

(16) The oscillation damper 5 comprises a movement limiter 1 facing the pendulum 10.

(17) The fixed part 3 has a substantially truncated conical shape. The shape will maximise the contact surface between the pendulum 10 and the movement limiter 1.

(18) FIG. 4 is a sectional view of an embodiment of an oscillation damper 5 where the pendulum is suspended by three suspensions 2.

(19) The oscillation damper 5 comprises at least three suspensions 2 having a suspension length. The suspension length determines the frequency which is to be dampened.

(20) The oscillation damper 5 comprises a pendulum 10 suspended by the suspensions 2. The pendulum 10 has a pendulum mass. The pendulum 10 comprises a fixed part 3 having a side face 11 and a slideable part 14 for collision with a movement limiter 1.

(21) The slideable part 14 is a substantial portion of the pendulum mass such as 20-90%, 20-60% or 20% to 40% of the pendulum mass. The slideable part 14 comprises one or more stacked plates 4 which are positioned on the fixed part 3 and extend beyond the side face 11.

(22) The oscillation damper 5 comprises a movement limiter 1 facing the pendulum 10.

(23) The fixed part 3 has a substantially cylindrical shape. The shape will maximise the contact surface between the pendulum 10 and the movement limiter 1.

(24) FIG. 5 is a sectional view of another embodiment of an oscillation damper 5 where the pendulum 10 is suspended by a suspension 2.

(25) The oscillation damper 5 comprises a suspension 2 having a suspension length. The suspension length determines the frequency which is to be dampened.

(26) The oscillation damper 5 comprises a pendulum 10 suspended by the suspension 2. The pendulum 10 has a pendulum mass. The pendulum 10 comprises a fixed part 3 having a side face 11 and a slideable part 14 for collision.

(27) The slideable part 14 is a substantial portion of the pendulum mass such as 20-90%, 20-60% or 20% to 40% of the pendulum mass. The slideable part 14 comprises one or more stacked plates 4 which are positioned on the fixed part 3 and extend beyond the side face 11.

(28) The oscillation damper 5 comprises a movement limiter 1 facing the pendulum 10.

(29) The fixed part 3 has a substantially truncated conical shape. The shape will maximise the contact surface between the pendulum 10 and the movement limiter 1.

(30) FIG. 6 is a sectional view of another embodiment of an oscillation damper 5 where the pendulum is suspended in three suspensions 2.

(31) The oscillation damper 5 comprises at least three suspensions 2 having a suspension length. The suspension length determines the frequency which is to be dampened.

(32) The oscillation damper 5 comprises a pendulum 10 suspended by the suspension 2. The pendulum 10 has a pendulum mass. The pendulum 10 comprises a fixed part 3 having a side face 11 and a slideable part 14 for collision.

(33) The slideable part 14 is a substantial portion of the pendulum mass such as 20-90%, 20-60% or 20% to 40% of the pendulum mass. The slideable part 14 comprises one or more stacked plates 4 which are positioned on the fixed part 3 and extend beyond the side face 11.

(34) The oscillation damper 5 comprises a movement limiter 1 facing the pendulum 10.

(35) The fixed part 3 has a substantially cylindrical shape. The shape will maximise the contact surface between the pendulum 10 and the movement limiter 1.

(36) As an example:

(37) 6 is a wind turbine tower. 5 is an example of disposition of an oscillation damper in the tower. 9 is a tower section where an oscillation damper is located at the top. 8 is a platform by which the oscillation damper can be serviced. 5 is an oscillation damper and 7 is a tower flange.

(38) 1 shows an movement limiter wherein the pendulum is suspended. 2 is the suspension by which the pendulum is suspended. The length of the suspension 2 can be adapted to the wind turbine tower frequency. 3 is the fixed part of the pendulum. 4 shows the disposition of the weight plates, also called shock absorber plates.

(39) The plates 4 have different sizes and provide that the uppermost plate, which is the largest, strikes first when the pendulum 3 swings and strikes the movement limiter 1; this starts with providing a small resistance to the pendulum, and when the second plate 4 strikes, the force is increased.