Active tuned mass damper applied to offshore monopile wind turbine installation

Abstract

An active tuned mass damper applied to the offshore monopile wind turbine belongs to the field of marine technology. A mass block is connected to the inner wall of the tower through a spring. The two ends of the damper and the force actuator are connected to the mass block and the inner wall of the tower, respectively. When the installation of tower is finished, the spring and the damper begin to work. The movement of mass block will partly offset the movement of the tower caused by the wave force. The force actuator starts to work before the mating. The exact position of the nacelle can be obtained from the Global Positioning System (DGPS). The position of tower can be adjusted in the horizontal plane through the force actuator. So, the offshore installation time for nacelle will be saved. The whole installation time and cost will also be reduced.

Claims

1. An active tuned mass damper suitable for an offshore monopile wind turbine, comprising a mass block, a spring, a damper, a force actuator, a controller, an electric motor and a battery installed on a tower, and a sensor, which is a Differential Global Positioning System (DGPS), installed in a nacelle; wherein the mass block is connected to an inner wall of the tower by the spring, two ends of the damper and the force actuator are connected to the mass block and the inner wall of the tower respectively; the mass block, the spring, the damper is selected according to the vibration theory, and optimized and adjusted based on a first structural natural frequency of the tower; when the installation of the tower is finished, the spring and the damper start to work; movements of the tower caused by a wave force will be partly offset by the movement of the mass block; before mating of the nacelle and the tower, the force actuator begins to work; the precise position of the nacelle can be obtained by the DGPS, and the position of the tower in the horizontal plane is adjusted through the force actuator.

2. The active tuned mass damper according to claim 1, wherein the mass block is solid or liquid unit.

3. The active tuned mass damper according to claim 2, wherein the damper is made of rubber.

4. The active tuned mass damper described in claim 3, wherein the force actuator is driven by the controller and the electric motor located in the tower.

5. The active tuned mass damper according to claim 2, wherein the force actuator is driven by the controller and the electric motor located in the tower.

6. The active tuned mass damper according to claim 1, wherein the damper is made of rubber.

7. The active tuned mass damper described in claim 6, wherein the force actuator is driven by the controller and the electric motor located in the tower.

8. The active tuned mass damper described in claim 1, wherein the force actuator is driven by the controller and the electric motor located in the tower.

9. The active tuned mass damper according to claim 1, wherein the force actuator is driven by the controller and the electric motor located in the tower.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1, side view of the off-shore single blade installation (x-z plane).

(2) FIG. 2, the diagram of the main components of the active tuned mass damper.

(3) FIG. 3, the diagram of the force actuator feedback.

(4) FIGS. 4(a) and 4(b) of the nacelle mating.

(5) FIG. 5, the nacelle profile after mating.

(6) FIG. 6, the front view of the off-shore monopile wind turbine after mating.

(7) In the figures: 1 Jack-up installation vessel; 2 Crane; 3 Vertical tugger line; 4 Horizontal tugger line; 5 Nacelle; 6 Hub; 7 Tower; 8 Mass block; 9 Spring; 10 Damper; 11 Force actuator; 12 Tower roof; 13 Flange hole; 14 Blade; 15 Monopile; 16 Sea level; 17 Seabed.

DETAIL DESCRIPTION

(8) The specific embodiments of the present invention are further described below in conjunction with the drawings and technical solutions.

(9) The active tuned mass damper applied to offshore monopile wind turbine installation is carried out as follows:

(10) FIG. 1 is the side view of the offshore single blade installation (x-z plane). The wind speed direction is x direction. The installed wind turbine is 6 MW level whose nacelle length is 10 m and weight is 360t. The height of the nacelle is 100 m above the sea level. The nacelle is connected to the crane by two horizontal tugger lines and a vertical tugger line. The horizontal tugger lines are used to limit the movement of the blade on the x-y plane. Lift the nacelle from the jack-up installation vessel gradually above the tower and prepare for the mating process.

(11) FIG. 2 is the diagram of the main components of the active tuned mass damper. The weight of the mass block is 20 ton. The spring rigidity is 5000 N/m. The damping coefficient is 9000 Ns/m. The corresponding natural frequency is 0.28 Hz. The force actuator could be a piston structure and driven by the electric motor. The parameter of the force actuator can be optimally designed according to the wind turbine structure.

(12) FIG. 3 is the diagram of the force actuator feedback. At each moment, the actuator calculates the force needed for the next moment according to the position difference between the tower and the nacelle. Adjust the tower position by the force actuator.

(13) FIGS. 4(a) and 4(b) present views of the nacelle's installation. Before the mating, the circular holes at the bottom of the nacelle are very close to the top of the tower. But it is not easy for the point-to-point mating. Usually, labors are needed to complete the mating. If the active tuned mass damper is used, the nacelle and the tower could be fully aligned t under the assistance of the force actuator.

(14) FIG. 5 is the nacelle profile after mating. The nacelle and the top of the tower is fixed by bolts through the flange hole.

(15) FIG. 6 is an offshore 6 MW wind turbine after installation.