JP2024083160A - Wind power generator - Google Patents

Abstract

To provide a wind power generator which can keep its attitude horizontally.SOLUTION: A wind power generator has a wind turbine including a rotor which receives wind so as to rotate, an electric generator which receives rotational force of the rotor so as to generate electricity, a main floating body which supports the wind turbine, a plurality of sub floating bodies which are disposed in positions away from the main floating body such that they surround the main floating body, and at least a part or all of which is located above the water level, and a connection member connecting the main floating body and the sub floating body.SELECTED DRAWING: Figure 1

Description

This disclosure relates to a wind power generation device.

An example of a wind power generation device is the wind power generation device described in Patent Document 1.

JP 2021-172211 A

The wind power generation device in Patent Document 1 is a so-called floating offshore wind power generation device. Compared to land-based wind power generation devices, offshore wind power generation devices can generate power more efficiently and have larger wind turbines, and are becoming more widely used.

However, floating offshore wind turbines have the problem that the turbines sway due to the effects of waves and wind, and if they tilt beyond a certain level, they stop operating and power generation efficiency decreases.

In addition, when the float sways, an impact tensile force may be applied to the mooring lines, such as chains, that connect the float to the seabed, causing damage to the mooring lines and increasing the flooded area of the wind turbine, which can lead to maintenance issues such as increased corrosion areas.

Taking the above facts into consideration, this disclosure aims to provide a wind power generation device that makes it possible to suppress tilt.

The wind power generation device according to the first aspect comprises a wind turbine with a rotor that rotates when exposed to wind, a generator that generates electricity by receiving the rotational force of the rotor, a main float that supports the wind turbine, a number of secondary floats that are arranged at a distance from the main float so as to surround the main float and are at least partially or entirely located above the water surface, and a connecting member that connects the main float and the secondary float.

In the wind power generation device according to the first aspect, when the rotor rotates in response to the wind, the generator generates electricity by receiving the rotational force of the rotor.

In the wind power generation device according to the first aspect, the wind turbine is supported on the main float, and the buoyancy of the main float allows the wind turbine to be positioned above the water surface.

When hit by relatively large waves or wind, the wind turbine tends to tilt downstream in the direction of the wave's movement or the wind's flow. When the wind turbine tilts, the secondary float on the side where the wind turbine is tilting sinks into the water, creating buoyancy on the secondary float.

The buoyancy is transmitted to the main floating body that supports the wind turbine via the connecting member and acts as a restoring force against the force that causes the wind turbine to tilt, suppressing the tilt of the wind turbine compared to when the secondary floating body is not provided. This makes it possible to suppress the tilt of the wind turbine.

The wind power generation device according to the second aspect is the wind power generation device according to the first aspect, in which four or more of the secondary floating bodies are arranged at equal intervals in the circumferential direction.

In the wind power generation device according to the second aspect, four or more secondary floats are arranged at equal intervals in the circumferential direction, so the tilt of the wind turbine can be suppressed due to waves and wind from various directions, compared to a case in which there are three or fewer secondary floats.

The wind power generation device according to the third aspect is the wind power generation device according to the first or second aspect, in which one of the secondary floating bodies adjacent to the other in the circumferential direction is connected by a circumferential connecting member.

In the wind power generation device according to the third aspect, adjacent secondary floats are connected to each other in the circumferential direction by a circumferential connecting member, so deformation of the connecting member can be suppressed and durability can be increased compared to when the secondary floats are connected to the main float only by a connecting member.

The wind power generation device according to the fourth aspect is the wind power generation device according to the first to third aspects, in which the secondary floating body is a hollow structure made of an elastic material having a specific gravity lighter than that of metal.

By making the secondary float a hollow structure made of an elastic material with a lower specific gravity than metal, the secondary float can be made lighter than secondary floats made of metal.

As described above, the wind turbine generator disclosed herein can maintain a horizontal position.

1 is a front view showing a wind turbine generator according to a first embodiment of the present disclosure. 1 is a plan view showing the arrangement of a secondary floating body of a wind turbine power generation device according to a first embodiment of the present disclosure. FIG. 1 is a side view showing an upper part of a tower of a wind turbine power generating apparatus according to a first embodiment of the present disclosure. FIG. FIG. 2 is a front view showing an inclined state of the wind turbine power generating device according to the first embodiment of the present disclosure. FIG. 11 is a cross-sectional view showing the periphery of a tower base of a wind turbine power generating device according to a second embodiment of the present disclosure. FIG. 11 is a partially cross-sectional perspective view showing the periphery of a sliding bearing of a wind turbine generator according to a second embodiment of the present disclosure. FIG. 11 is a cross-sectional view showing a sliding bearing used in a wind turbine generator according to a second embodiment of the present disclosure. FIG. 4 is an explanatory diagram showing the horizontal displacement and horizontal load curve of a vibration absorber. FIG. 11 is a plan view showing the arrangement of a secondary floating body of a wind turbine power generation device according to a third embodiment of the present disclosure.

[First embodiment]
A wind turbine generator 10 according to a first embodiment of the present disclosure will be described with reference to Figs. 1 to 4 .

As shown in FIG. 1, the wind power generation device 10, for example, has a hollow, cylindrical steel main float 22.

As shown in Figures 1 and 2, the tower 14 is erected in the center of the main float 22. The main float 22 and the tower 14 are fixed together, for example, by bolts, welding, etc.

As shown in FIG. 1, the buoyancy of the main float 22 is determined so that a portion of its upper side is above the water surface WF. In other words, the tower 14 is positioned above the water surface WF, and water does not hit the tower 14 when the waves are relatively small.

As shown in FIG. 3, a nacelle 16 is provided on top of the tower 14, and the nacelle 16 houses a generator 20 that generates electricity by rotating a rotor 18. The tower 14 has a hollow structure, for example, and is made of steel plates or the like. The inside of the tower 14 is sealed to prevent the intrusion of rainwater, seawater, etc.

The tower 14, nacelle 16, rotor 18, and generator 20 may have a conventional structure. In this embodiment, the rotor 18 is made up of the hub 18A and blades 18B, and the tower 14, nacelle 16, and rotor 18 make up the wind turbine 11.

As shown in FIG. 1, the wind turbine 11 of this embodiment is, as an example, a horizontal axis wind turbine known as a propeller type.

As shown in FIG. 2, a connecting member 24 is attached to the main float 22. The main float 22 and the connecting member 24 are fixed to each other, for example, by bolts, welding, etc.

There are multiple connecting members 24 (four in this embodiment) extending radially (diametrically outward) from the main float 22, and the secondary float 26 is fixed to the end of each connecting member 24.

In addition, adjacent sub-floats 26 are connected to each other by an arc-shaped circumferential connecting member 28.

The four connecting members 24 are arranged at 90° intervals in the circumferential direction. In other words, the four connecting members 24 are arranged at equal intervals in the circumferential direction. The length L of each connecting member 24 is the same. The connecting members 24 do not have to be arranged at equal intervals in the circumferential direction, and the length L of each connecting member 24 does not have to be the same. If the rotor 18 is displaced horizontally relative to the axis of the tower 14 and installed on the tower, the center of gravity of the wind turbine will shift horizontally, so the buoyancy auxiliary mechanism (connecting member 24, secondary float 26, circumferential connecting member 28, etc.) may also have a non-linearly symmetrical pattern in order to balance. In order to make the attitude of the wind turbine 11 vertical, it is preferable to change the length of some of the connecting members 24 or change the spacing of the secondary float 26 in part so that the wind turbine 11 does not tilt, and to balance the entire wind power generation device 10.

In this embodiment, the secondary float 26 is, as an example, a hollow steel sphere. Note that the shape of the secondary float 26 is not limited to a sphere, and may be a cylinder, a barrel shape with a bulging center, a cube, etc.

The connecting member 24 and the circumferential connecting member 28 can be formed, for example, from steel material, and, for example, the secondary floating body 26 is fixed to the connecting member 24 and the circumferential connecting member 28 by bolts, welding, or the like.

The material constituting the secondary float 26 is not limited to steel, and may be an elastic material, such as vulcanized rubber, urethane resin, or other elastic synthetic resin (elastomer resin). For example, the secondary float 26 may be a hollow structure made of an elastic material such as rubber, with air filled inside. By making the secondary float 26 a hollow structure made of an elastic material with a lower specific gravity than metal, the secondary float 26 can be made lighter than a secondary float made of metal. Reinforcing cords, woven sheets, etc. may be embedded in the elastic material constituting the secondary float 26.

As shown in FIG. 1, each secondary floating body 26 is located above the water surface WF (a flat water surface without waves in FIG. 1) and is arranged on the same plane parallel to the water surface WF. Also, in the example shown in FIG. 1, each secondary floating body 26 is located above the water surface WF so as not to generate buoyancy.

As shown in FIG. 1, the wind turbine 10 of this embodiment can be moored to the seabed (not shown) by mooring lines 34, similar to conventional floating offshore wind turbines.

In addition, the electricity generated by the generator 20 can be transmitted to land via a power transmission line 36, for example.

(Action, Effect)
In the wind power generation device 10 of this embodiment, when relatively large waves or wind are received, as shown in Figure 4, the wind turbine 11 of the wind power generation device 10 tends to tilt downstream in the direction of wave WA (in the direction of arrow A) or downstream in the flow of wind (not shown) (as an example, the left side in Figure 4). However, when the wind turbine 11 tilts, the secondary float 26 on the tilting side of the wind turbine 11 (in Figure 4, the left secondary float 26) sinks in the water, and a buoyancy F is generated on the secondary float 26.

The buoyancy F is transmitted to the main floating body 22 on which the wind turbine 11 is mounted via the connecting member 24, and acts as a restoring force against the force that causes the wind turbine 11 to tilt, thereby suppressing tilting of the wind turbine 11 compared to the case where the secondary floating body 26 is not provided. In other words, it becomes possible to keep the wind turbine 10 horizontal, and the wind turbine 11 is prevented from tilting excessively, which would cause the wind turbine 11 to stop operating.
Furthermore, when the wind turbine 11 moves suddenly and tries to tilt, the secondary floating body 26 on the tilting side tries to sink into the water, but at that time, the secondary floating body 26 encounters large resistance from the water, and the sudden sinking, i.e., the sudden movement of the wind turbine 11, can be suppressed.

In addition, the inclination of the wind turbine 11 is suppressed; in other words, the wind power generation device 10 is kept horizontal, which suppresses the application of shock tension to the mooring line 34 and thus prevents the mooring line 34 from being damaged.

In addition, excessive tilting of the wind turbine 11 is prevented, which prevents the flooded area (area submerged in water and in contact with water) from becoming larger, and prevents the corrosion area (e.g., the surface of the tower 14) from becoming larger.

In the wind power generation device 10 of this embodiment, the four secondary floats 26 are arranged at equal intervals in the circumferential direction, so that the inclination of the wind turbine 11 due to waves and wind from various directions can be suppressed compared to when there are three or fewer secondary floats 26.

In the wind power generation device 10 of this embodiment, one secondary float 26 and the other secondary float 26 adjacent in the circumferential direction are connected by a circumferential connecting member 28, so deformation of the connecting member 24 can be suppressed and durability can be improved compared to when the secondary float 26 is connected to the main float 22 by only the connecting member 24.

In addition, it is preferable that the secondary floating body 26 has a volume of 0.13 ^m2 or more, for example.
If the volume of the secondary floating bodies 26 is too small, the buoyancy of each secondary floating body 26 is small, and therefore a large number of secondary floating bodies 26 are required.

The length L of the connecting member 24 (the length from the main float 22 to the secondary float 26) is preferably, for example, 0.1 m or more and 20 m or less.

If the length L of the connecting member 24 is too short, the restoring force (determined by the buoyancy of the secondary float 26 times the length L) will be insufficient. On the other hand, if the length L of the connecting member 24 is too long, the weight of the connecting member 24 will be large, making it necessary to increase the buoyancy of the main float 22 that supports the weight of the connecting member 24, and the size of the main float 22 will increase. In addition, if the length L of the connecting member 24 is too long, large stress will be generated in the connecting member 24 and in the joint between the connecting member 24 and the main float 22.

As shown in FIG. 1, in this embodiment, the secondary float 26 is positioned above the flat water surface WF, but the lower end of the secondary float 26 may be in contact with the flat water surface WF as shown in FIG. 1, or, although not shown, the lower end may be slightly spaced from the water surface WF.

For example, if all the secondary floats 26 are submerged, the restoring force when the tower 14 tilts due to waves or wind (more specifically, the restoring force generated by submerging the secondary float 26 on the side where the wind turbine 11 is tilted in comparison with the secondary float 26 on the opposite side) is less likely to occur compared to this embodiment.

Therefore, when the secondary float 26 is installed so that its lower end is in contact with the flat water surface WF (for example, when part of the lower part of the secondary float 26 is submerged), in order to obtain sufficient restoring force when the tower 14 tilts, it is preferable to determine the height position of the secondary float 26 so that the buoyancy generated in the secondary float 26 is less than 10% of the buoyancy when the entire secondary float 26 is completely submerged.
In other words, it is preferable that the secondary floating body 26 is provided so that 90% or more of its volume is above the water surface WF.

The secondary floats 26 may have their lower ends spaced slightly away from the flat water surface WF, but in that case, it is preferable to position each secondary float 26 so that when the wind turbine 11 is tilted at a certain angle (e.g., 10°) or more relative to the vertical, at least a portion of the secondary float 26 on the tilted side sinks in the water, generating buoyancy.

Second Embodiment
A wind turbine generator 10 according to a second embodiment of the present disclosure will be described with reference to Figures 5 to 8. Note that the same components as those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

As shown in FIG. 5, in the wind power generation device 10 of this embodiment, the tower 14 is supported on the main floating body 22 via a sliding bearing 110.

In this embodiment, the tower 14 has its bottom fixed to a tower base plate 120. As shown in Figures 5 to 7, the sliding bearing 110 includes a bearing portion 130 attached to the tower base plate 120, and a sliding plate 140 attached to the main float 22, abutting against the bearing portion 130 and supporting the bearing portion 130.

The sliding bearing 110 can be used as a seismic isolation device installed between the tower base plate 120 and the main floating body 22. A seismic isolation device equipped with the sliding bearing 110 can allow the support part 130 and the sliding plate 140 to slide relative to each other when a lateral bending force acts on the tower 14 due to wind. In addition, the tower 14 fixed to the tower base plate 120 is given seismic isolation performance by the sliding bearing 110.

As shown in Figures 6 and 7, the tower base plate 120 has bolt holes 125 formed in the bottom surface 122, and the flange 131 of the support part 130 is bolted to it, as described below.

(Support section)
The support part 130 is a member that continues to support the tower 14. The support part 130 is a member that transmits the loads of the rotor 18, the nacelle 16, the tower 14, the tower base plate 120, etc., to the main floating body 22. The support part 130 is configured to include a flange 131 attached to the bottom surface 122 of the tower base plate 120, a vibration absorber 132 formed on the lower part of the flange 131 and absorbing vibrations, and a sliding member 133 formed on the lower part of the vibration absorber 132 and abutting against a sliding surface 141 of the sliding plate 140.

The flange 131 has bolt insertion holes 135, and the flange 131 and the tower base plate 120 are joined with bolts 138. The flange 131, the vibration absorber 132, and the sliding member 133 are joined to each other in the vertical direction. The vibration absorber 132 is made of laminated rubber in which rubber 132a and steel plate 132b are layered in order.

(Slide plate)
The sliding plate 140 is a plate material on which an object slides, and has a sliding surface 141 formed on its surface against which the sliding material 133 of the support part 130 abuts. The surface of the sliding surface 141 is sintered and coated with PTFE (polytetrafluoroethylene) or the like. In addition, the sliding plate 140 is not joined to the support part 130, and when a horizontal force is applied, the sliding material 133 of the support part 130 can slide on the sliding surface 141.

As shown in FIG. 6, the sliding plate 140 is formed in a rectangular shape. As shown in FIG. 6 and FIG. 7, bolt insertion holes 145 are formed in the four corners of the sliding plate 140, and bolt holes 155 are formed in the main float 22. The sliding plate 140 is fixed to the main float 22 with bolts 158.

As shown in Figures 5 and 6, the wind power generation device 10 is equipped with a damper 160 and a displacement restriction member 162.

Dampers 160 are installed on the upper surface of the main floating body 22 at positions facing each side of the sliding plate 140. The dampers 160 generate a damping force that suppresses the horizontal shaking of the tower base plate 120. In other words, the dampers 160 generate a damping force. As the dampers 160, oil dampers, air dampers, viscoelastic bodies such as rubber with a large damping rate, etc. can be used, and there is no particular restriction on the type.

The main float 22 and the tower base plate 120 are connected by a displacement restriction member 162 that restricts the relative displacement between the main float 22 and the tower base plate 120. One example of the displacement restriction member 162 is a metal chain covered with rubber, and it acts as a stopper that restricts the tower base plate 120 from being displaced more than necessary. The type of the displacement restriction member 162 is not particularly important, and one example is a block-shaped member that is fixed to the main float 22 and is provided at a position horizontally spaced from the end of the tower base plate 120.

As shown in FIG. 5, the outer periphery of the tower base plate 120 and the upper surface of the main float 22 are connected with a waterproof cover 164 made of a flexible material, which prevents water from getting on the sliding bearing 110, the damper 160, the displacement control member 162, etc.

(Action)
When the rotor 18 of the wind turbine generator 10 is subjected to wind, bending occurs at the base of the tower 14 and the wind turbine generator 10 is subjected to repeated loads due to the influence of the wind. The repeated loads can cause fatigue failure.

One way to solve the fatigue failure of the base of the tower 14 is to increase the rigidity of the tower structure, but this would increase costs due to the increased thickness and weight of the components. In addition, large-scale heavy machinery would be required to replace components after fatigue failure occurs, resulting in extremely high maintenance costs equivalent to those incurred at the time of initial installation. Furthermore, partial repairs would only create new strength weaknesses, and similar problems would continue to occur, so this is not an essential solution.

In the wind power generation device 10 of this embodiment, when the rotor 18 receives wind and a horizontal external force is input to the upper part of the tower 14, a horizontal displacement occurs between the tower base plate 120 on which the tower 14 is mounted and the main floating body 22, making it difficult for bending stress to occur in the base of the tower 14. By making it difficult for bending stress to occur in the base of the tower 14, the durability of the tower 14 can be improved.
In addition, by improving the durability of the tower 14, it becomes possible to enlarge the rotor 18 and increase the amount of power generation.

When the displacement is small, the vibration absorber 132 absorbs the displacement energy by shear deformation, and when the displacement becomes large, the friction limit between the sliding material 133 of the support part 130 and the sliding surface 41 of the sliding plate 140 is exceeded, and the support part 130 slides on the sliding plate 140.

8 shows the horizontal displacement and horizontal load curve of the vibration absorber (laminated rubber part) 132 of the support part 130, in which the laminated rubber part of the support part 130 undergoes elastic deformation in the low load region before the tower 14 starts to slide, making it possible to prevent the tower 14 from constantly moving. The elastic modulus of the laminated rubber part of the support part 130 can be adjusted by the rubber material and product shape.
Incidentally, the elastic modulus of the laminated rubber portion = shear elastic modulus x effective area of rubber portion / rubber layer thickness.

The damper 160 suppresses horizontal shaking of the tower base plate 120, and the displacement restriction member 162 restricts excessive displacement of the tower base plate 120.

In this embodiment, the tower 14 is supported by a single sliding bearing 110, but the tower 14 may be supported by multiple sliding bearings 110.

[Third embodiment]
A wind turbine generator 10 according to a third embodiment of the present disclosure will be described with reference to Fig. 9. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted.
In the wind turbine generator 10 of the first embodiment, the four sub-floats 26 are arranged on the same circumference, but the present disclosure is not limited to this, and for example, as shown in Fig. 9, a configuration may be adopted in which a plurality of sub-floats 26 are further arranged in the circumferential direction on the outer periphery of the four sub-floats 26 arranged in the circumferential direction. This makes it possible to obtain a greater restoring force than in the first embodiment.

[Other embodiments]
While one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above, and it goes without saying that the present disclosure can be implemented in various modified forms without departing from the spirit and scope of the present disclosure.

In the first embodiment, four connecting members 24 were attached to the main float 22, but the number of connecting members 24 may be five or more.

In addition, in the above embodiment, multiple secondary floating bodies 6 are arranged at equal intervals in the circumferential direction, but they may also be arranged at unequal intervals in the circumferential direction.

In the first embodiment, the length L of each connecting member 24 was the same, but the length L of each connecting member 24 can be changed as appropriate, and the length L of each connecting member 24 does not have to be the same for all connecting members 24.

In the second embodiment, the tower 14 is supported by a sliding bearing 110, but the tower 14 may also be supported by a seismic isolation device.

The wind turbine 11 in the above embodiment was a horizontal axis wind turbine, also known as a propeller type, but the type of the wind turbine 11 is not limited to that in the above embodiment, and may be of other types, such as a vertical axis wind turbine.

10: Wind power generation device, 11: Wind turbine, 14: Tower (wind turbine), 18: Rotor (wind turbine), 20: Generator, 22: Main float, 24: Connecting member, 26: Secondary float, 28: Circumferential connecting member.

Claims (4)

A windmill with a rotor that rotates when it receives wind,
a generator that receives the rotational force of the rotor and generates electricity;
A main floating body supporting the wind turbine;
A plurality of secondary floats are arranged at a position spaced apart from the main float so as to surround the main float, and are at least partially or entirely located above the water surface;
A connecting member that connects the main floating body and the sub floating body;
A wind power generation device having the above structure. Four or more of the secondary floating bodies are arranged at equal intervals in the circumferential direction.
The wind turbine generator according to claim 1 . One of the sub-floats and the other of the sub-floats adjacent to each other in the circumferential direction are connected to each other by a circumferential connecting member.
The wind turbine generator according to claim 2. The secondary floating body is a hollow structure made of an elastic material having a lower specific gravity than metal.
The wind turbine generator according to claim 1 .