JP7574234B2 - Wave power generation device and offshore wind power generation system - Google Patents

Description

Embodiments of the present invention relate to wave power generation devices and offshore wind power generation systems.

Offshore wind power generation systems that generate electricity offshore have the advantage of being able to generate electricity using the stable winds offshore. For example, when the water depth suddenly increases offshore, it is difficult to establish foundations on the seabed and secure the wind power generation equipment, so floating offshore wind power generation equipment is considered to be an effective option. Since offshore wind power generation equipment moves up and down with the waves, it is designed to be detuned from the natural period of the waves. This prevents damage to the equipment from vibration. It is also considered important to maintain the equipment by suppressing vibration during high waves caused by typhoons, etc.

Offshore wind power generation facilities can generate electricity by catching wind, but an external power source is used to control the float. If the external power source draws power from the power grid, there is a risk that the power grid will be cut off in the event of a disaster such as a typhoon. If the external power source is lost, the float cannot be controlled, and it has been pointed out that there is a risk that the float may collapse in some cases. For this reason, it is desirable to have a power source that can be secured even in emergencies such as when the power grid is cut off.

An example of such a power source is a storage battery. However, the capacity of a storage battery is limited. Therefore, if the loss of external power source continues for an extended period of time, there is a risk of power shortage.

Another example would be to use the electricity generated by wave power generation as a power source. Wave power generation is a power generation method that generates electricity by converting vibrations caused by waves into kinetic energy. Wave power generation can also be called vibration power generation. A wave power generation device can be constructed by attaching a power generation float to a float of an offshore wind power generation facility so that it can vibrate relative to the float. The greater the relative vibration, the greater the amount of electricity generated.

However, when the relative vibration is large, there is a risk that the vibration will propagate from one floating body with a large vibration to the other floating body, amplifying the vibration. When the relative vibration is small, there is little risk of vibration propagation, but the amount of power generated may decrease. This makes it difficult to secure the necessary power.

Patent No. 5495117 Patent No. 3718683

The embodiments of the present invention have been made with these points in mind, and aim to provide a wave power generation device and an offshore wind power generation system that can suppress vibrations and increase the amount of power generated by wave power.

The wave power generation device according to the embodiment includes a first structure floating on the water, a second structure floating on the water and displaceable relative to the first structure, an intermediate structure, a first conversion mechanism, and a first device generator. The intermediate structure is elastically connected to each of the first structure and the second structure, and is displaceable relative to each of the first structure and the second structure. The first conversion mechanism includes a first conversion rotor and converts the relative displacement between the first structure and the intermediate structure into a rotational displacement of the first conversion rotor. The first device generator includes a first generator rotor, and the first generator rotor rotates with the rotational displacement of the first conversion rotor to generate power. The first generator rotor and the first conversion rotor form a first rotor that functions as an inertial mass element that reduces vibration transmission from the intermediate structure to the first structure.

The offshore wind power generation system according to the embodiment includes the wave power generation device described above and a wind power generation facility supported by the wave power generation device.

According to an embodiment of the present invention, it is possible to suppress vibrations and increase the amount of electricity generated by wave power.

FIG. 1 is a schematic diagram showing an offshore wind power generation system according to a first embodiment. FIG. 2 is a schematic cross-sectional view showing the wave power generation device shown in FIG. FIG. 3 is a diagram showing a dynamic model of the wave power generation device of FIG. FIG. 4 is a schematic cross-sectional view showing a typical wave power generation device. FIG. 5 is a diagram showing a dynamic model of the wave power generation device of FIG. FIG. 6 is a graph showing the frequency response of the wave power generator of FIG. FIG. 7 is a graph showing the frequency response of the wave power generator of FIG. FIG. 8 is a schematic cross-sectional view showing a wave power generating device according to the second embodiment. FIG. 9 is a top view of FIG. FIG. 10 is a top view showing a modification of FIG. FIG. 11 is a schematic cross-sectional view showing a wave power generating device according to the third embodiment. FIG. 12 is a schematic cross-sectional view showing a wave power generating device according to the fourth embodiment. FIG. 13 is a diagram showing a dynamic model of the wave power generation device of FIG. FIG. 14 is a graph showing the frequency response of the wave power generator of FIG.

The following describes a wave power generation device and an offshore wind power generation system according to an embodiment of the present invention, with reference to the drawings.

(First embodiment)
A wave power generator and an offshore wind power generation system according to the present embodiment will be described with reference to Figures 1 to 7. Here, an example of a wave power generator applied to an offshore wind power generation system will be described. However, application examples of the wave power generator are not limited to this.

First, an offshore wind power generation system 1 to which the wave power generation device according to this embodiment is applied will be described with reference to FIG. 1. FIG. 1 shows a spar-type offshore wind power generation system as an example.

The offshore wind power generation system 1 shown in FIG. 1 includes a wind power generation facility 2 and a wave power generation device 10. The wind power generation facility 2 includes a first floating body 21, a tower structure 3, and a wind power generator main body 4.

The first float 21 floats on the ocean. The first float 21 has a first central axis L1, and is formed in a cylindrical shape extending along the first central axis L1. When the first float 21 is not swaying, the first central axis L1 is along the vertical direction. A part of the first float 21 is located below the water surface and is immersed in the surrounding seawater. The water surface is indicated by the symbol W in Figure 1 etc. The first float 21 is configured to withstand water pressure.

A weight section (not shown) filled with a weight such as concrete or ballast water is provided at the bottom of the first float 21. This lowers the center of gravity of the first float 21 and balances the buoyancy of the first float 21 with the gravity of the offshore wind power generation system 1. In this way, the stability of the first float 21 floating on the ocean is increased.

The tower structure 3 is located above the first floating body 21 and extends upward from the first floating body 21. The tower structure 3 is supported by the first floating body 21 and is formed in a columnar shape that extends vertically in an elongated manner.

The wind power generator body 4 is installed at the top end of the tower structure 3. The wind power generator body 4 is supported by the first floating body 21 via the tower structure 3. The wind power generator body 4 is rotatable in a horizontal plane relative to the tower structure 3 according to the wind direction, etc. The wind power generator body 4 includes a nacelle 4a rotatably supported by the tower structure 3, and a power generating rotor 4b rotatably mounted on the nacelle 4a. The nacelle 4a houses a wind power generator 4c that generates power by rotating the power generating rotor 4b. The power generating rotor 4b includes a plurality of blades 4d.

Such a wind power generation facility 2 vibrates vertically when subjected to the excitation force of waves. This vibration is also called heave.

Next, the wave power generation device 10 according to this embodiment will be described with reference to FIG. 2. FIG. 2 is a schematic cross-sectional view of the wave power generation device shown in FIG. 1. Note that the wind power generation facility 2 is omitted in FIG. 2.

The wave power generation device 10 shown in FIG. 2 includes a first structure 20, a second structure 30, an intermediate structure 40, a first elastic body 50, a second elastic body 60, a first conversion mechanism 70, and a first device generator 80.

The first structure 20 is a structure floating on the ocean. The first structure 20 includes the first float 21, the spokes 22, and the first rod 23 described above. The first float 21 is a component of the wind power generation facility 2 and also a component of the wave power generation device 10. The first float 21 may have a larger cross-sectional area than the second float 31 described below. In this case, the stability of the first float 21 can be improved compared to the second float 31.

As described above, the first floating body 21 floats on the ocean. Therefore, the first floating body 21 vibrates in the vertical direction when subjected to the excitation force of the waves. The first floating body 21 can be considered to be elastically supported with respect to the stationary system. To model this, in FIG. 2, the first floating body 21 is elastically supported with respect to the stationary system by a first imaginary elastic body 11 having a spring constant k _4. The first imaginary elastic body 11 does not indicate the presence of a spring member, but is used to model the vertical movement of the first floating body 21 due to the buoyancy force received from the surrounding water. The natural frequency of the first floating body 21 may be designed to be sufficiently detuned with respect to the frequency of the waves.

The spokes 22 are connected to the upper part of the first floating body 21. The spokes 22 extend horizontally from the first floating body 21 to a position above the intermediate structure 40.

The first rod 23 extends downward from the spoke 22. The first rod 23 is formed in a cylindrical shape so as to extend along a second central axis L2 described below. The first rod 23 is inserted into an intermediate hollow portion 42 described below and passes through the intermediate hollow portion 42. An elastic body connecting portion 24 to which a first elastic body 50 is connected is fixed to the first rod 23.

The second structure 30 is a structure that can be displaced relative to the first structure 20. The second structure 30 floats on the ocean at a position different from that of the first structure 20. The second structure 30 includes a second floating body 31 and a second cavity portion 32.

The second float 31 floats on the ocean. The second float 31 has a second central axis L2 and is formed in a cylindrical shape extending along the second central axis L2. When the second float 31 is not swaying, the second central axis L2 is along the vertical direction. A part of the second float 31 is located below the water surface and is immersed in the surrounding seawater. The second float 31 is configured to withstand water pressure. The second float 31 may have a smaller cross-sectional area than the first float 21 described above. A weight portion (not shown) is provided on the lower part of the second float 31 in the same manner as the first float 21.

As described above, the second floating body 31 floats on the ocean. Therefore, the second floating body 31 vibrates in the vertical direction due to the excitation force of the waves. The second floating body 31 can be considered to be elastically supported with respect to the stationary system by the second virtual elastic body 12 having a spring constant _k1 , similar to the above-mentioned first virtual elastic body 11. The natural frequency of the second floating body 31 may be designed to be sufficiently detuned with respect to the frequency of the waves.

The second cavity 32 is formed in the second float 31. The second cavity 32 extends downward from the upper surface of the second float 31. The second cavity 32 is formed in a cylindrical shape so as to extend along the second central axis L2. The second cavity 32 may pass through the second float 31, but in the example shown in FIG. 2, the second cavity 32 does not pass through the second float 31 and terminates at an intermediate position. The second cavity 32 is located below the intermediate cavity 42 described later.

The lower part of the first rod 23 described above is inserted into the second cavity 32. The diameter of the second cavity 32 is larger than the outer diameter of the first rod 23.

A plurality of rollers 33 may be attached to the inner peripheral surface of the second float 31. The rollers 33 may be arranged at intervals in the axial direction d along the second central axis L2, or may be arranged at intervals in the circumferential direction. The rollers 33 are capable of rolling on the outer peripheral surface of the first rod 23. This allows the first rod 23 to be smoothly displaced relative to the second float 31. A guide rail (not shown) extending in the axial direction d may be attached to the outer peripheral surface of the first rod 23. This prevents the second structure 30 from rotating around the second central axis L2 relative to the first structure 20. In addition, the relative displacement of the first rod 23 with respect to the second float 31 can be guided in the axial direction d.

The intermediate structure 40 is elastically connected to each of the first structure 20 and the second structure 30, and is capable of relative displacement with respect to each of the first structure 20 and the second structure 30. The intermediate structure 40 includes a sleeve 41, an intermediate cavity 42, and a support base 43.

The sleeve 41 is located above the second float 31 and below the spokes 22. The sleeve 41 is formed in a cylindrical shape so as to extend along the second central axis L2.

The intermediate cavity 42 may penetrate the intermediate structure 40. More specifically, the intermediate cavity 42 is formed in the sleeve 41 and penetrates the sleeve 41. The intermediate cavity 42 is formed in a cylindrical shape so as to extend along the second central axis L2. The intermediate cavity 42 is located above the second cavity 32.

The first rod 23 described above is inserted into the intermediate cavity 42. The first rod 23 passes through the intermediate cavity 42 and extends into the second cavity 32 described above. This allows the first rod 23 to restrict the movement of the second structure 30 in a direction perpendicular to the second central axis L2. The diameter of the intermediate cavity 42 is larger than the outer diameter of the first rod 23.

A plurality of rollers 44 may be attached to the inner peripheral surface of the sleeve 41. The rollers 44 may be arranged at intervals in the axial direction d along the second central axis L2, or may be arranged at intervals in the circumferential direction. The rollers 44 are capable of rolling on the outer peripheral surface of the first rod 23. This allows the first rod 23 to be smoothly displaced relative to the sleeve 41. In addition, a guide rail (not shown) extending in the axial direction d may be attached to the outer peripheral surface of the first rod 23. This prevents the intermediate structure 40 from rotating about the second central axis L2 relative to the first structure 20. In addition, the relative displacement of the first rod 23 with respect to the sleeve 41 can be guided in the axial direction d.

The support stand 43 is located at the upper end of the sleeve 41 and is supported by the sleeve 41. The support stand 43 extends in the horizontal direction (perpendicular to the axial direction d).

The first elastic body 50 elastically connects the first structure 20 and the intermediate structure 40. More specifically, the first elastic body 50 connects the elastic body connecting portion 24 fixed to the first rod 23 to the sleeve 41 or the support frame 43. In the example shown in FIG. 2, one first elastic body 50 connects the elastic body connecting portion 24 to the sleeve 41 or the support frame 43, but the number of first elastic bodies 50 is arbitrary. The first elastic body 50 has a spring constant k _3. The first elastic body 50 may be formed of a spring member such as a coil spring, for example.

The second elastic body 60 elastically connects the second structure 30 and the intermediate structure 40. More specifically, the second elastic body 60 connects the second floating body 31 and the sleeve 41. In the example shown in Fig. 2, one second elastic body 60 connects the second floating body 31 and the sleeve 41, but the number of second elastic bodies 60 is arbitrary. The second elastic body 60 has a spring constant _k2 . The second elastic body 60 may be formed of a spring member such as a coil spring, for example.

The first conversion mechanism 70 includes a first conversion rotor 71. In this embodiment, the first conversion mechanism 70 is configured to convert the relative displacement between the first structure 20 and the intermediate structure 40 into a rotational displacement of the first conversion rotor 71.

More specifically, the first conversion mechanism 70 includes the first conversion rotor 71 and the first rack rail 72 described above.

The first rack rail 72 is an example of a first rack. The first rack rail 72 is provided on the first rod 23. More specifically, the first rack rail 72 is attached to the outer circumferential surface of the first rod 23. The first rack rail 72 extends in the axial direction d. The first rack rail 72 can be inserted into the intermediate cavity 42 of the intermediate structure 40. As described above, the intermediate structure 40 is restricted by a guide rail (not shown) extending in the axial direction d on the outer circumferential surface of the first rod 23, so that the intermediate structure 40 is prevented from rotating about the second central axis L2. Therefore, the first rack rail 72 can mesh with the first pinion gear 73 described later.

The first conversion rotor 71 includes a first pinion gear 73 and a first speed change gear 75.

The first pinion gear 73, together with the first speed change gear 75, constitutes the first conversion rotor 71 described above. The first pinion gear 73 meshes with the teeth of the first rack rail 72 via the first speed change gear 75, and converts the translational relative displacement in the axial direction d between the first structure 20 and the intermediate structure 40 into a rotational displacement.

The first pinion gear 73 is supported by the intermediate structure 40. More specifically, the first pinion gear 73 is rotatably supported by a bearing (not shown) on the support frame 43.

The first pinion gear 73 may be coaxially connected to the first generator rotor 81 described later. The rotation axis of the first pinion gear 73 may coincide with the rotation axis of the first generator rotor 81. Alternatively, the rotation axis of the first pinion gear 73 may be disposed in a direction perpendicular to the rotation axis of the first speed gear 75 described later when viewed from above.

The first speed change gear 75 is interposed between the first rack rail 72 and the first pinion gear 73. The first speed change gear 75 is configured to convert the relative displacement in the axial direction d between the first structure 20 and the intermediate structure 40 into a rotational displacement via the first rack rail 72, and to transmit this rotational displacement to the first pinion gear 73. The first speed change gear 75 and the first pinion gear 73 constitute the first conversion rotor 71.

The number of teeth of the first speed change gear 75 is different from the number of teeth of the first pinion gear 73. As a result, the rotational speed of the first speed change gear 75 is different from the rotational speed of the first pinion gear 73. In the example shown in FIG. 2, the pitch circle radius of the first speed change gear 75 is larger than the pitch circle radius of the first pinion gear 73. As a result, the number of teeth of the first speed change gear 75 is greater than the number of teeth of the first pinion gear 73, and the first speed change gear 75 increases the rotation speed of the first pinion gear 73.

で表される。 If the number of teeth of the first speed change gear 75 is _Z1 and the number of teeth of the first pinion gear 73 is _Z2 , the rotational speed ratio between the first speed change gear 75 and the first pinion gear 73, that is, the speed increase rate _ε1 of the first speed change device 74 is

It is expressed as:

The number of teeth of the first speed change gear 75 may be variable by the first speed change device 74. The first speed change device 74 is configured to be able to change the speed of the rotation of the first pinion gear 73. The first speed change device 74 may include a plurality of first speed change gears 75 with different numbers of teeth. The first speed change gears 75 meshing with the first rack rail 72 and the first pinion gear 73 may be switched by a switching unit (not shown). By switching the first speed change gear 75 to a gear with a different number of teeth, the first speed change device 74 can change the above-mentioned speed increase rate ε _1. The plurality of first speed change gears 75 may be arranged in parallel in a direction along the rotation axis of the first generator rotor 81 described later (a direction perpendicular to the paper surface of FIG. 2). The first speed change device 74 may include a first protective cover 76 that covers the first speed change gear 75. The first speed change device 74 is supported by the intermediate structure 40. More specifically, the first speed change device 74 is supported by the support frame 43. The first speed change gear 75 is rotatably supported by the support frame 43 via a bearing (not shown). The rotation axis of the first speed change gear 75 may be parallel to the rotation axis of the first pinion gear 73.

The first device generator 80 includes a first generator rotor 81. The first device generator 80 is configured so that the first generator rotor 81 rotates with the rotational displacement of the first conversion rotor 71 to generate electricity. The first device generator 80 is supported by the support frame 43 of the intermediate structure 40. In the example shown in FIG. 2, the first generator rotor 81 has a rotation axis along the horizontal direction. In the example shown in FIG. 2, one first device generator 80 is installed on the support frame 43. The rotational displacement converted from the relative displacement between the first structure 20 and the intermediate structure 40 by one first conversion mechanism 70 is transmitted to the first generator rotor 81 of the first device generator 80. A coaxial flywheel (not shown) may be attached to the first generator rotor 81. In this case, the moment of inertia of the flywheel may be included in the moment of inertia of the first generator rotor 81. This may adjust the moment of inertia of the first generator rotor 81.

The first generator rotor 81 and the first conversion rotor 71 described above constitute a first rotating body 90 that functions as an inertial mass element that reduces vibration transmission from the intermediate structure 40 to the first structure 20. In this embodiment, the first rotating body 90 is constituted by the first generator rotor 81, the first pinion gear 73, and the first speed gear 75.

The wave power generation device 10 according to this embodiment, configured as described above, is illustrated in the mechanical model shown in FIG. 3.

In FIG. 3, m ₁ is the mass of the second structure 30, m ₂ is the mass of the intermediate structure 40, and m ₃ is the mass of the first structure 20. More specifically, m ₁ is the mass of the second structure 30 plus the fluid effect such as the added mass of water. m ₂ is the mass of the intermediate structure 40 plus the mass of the stator of the first device generator 80 and the mass of the fixed side of the first speed change device 74. m ₃ is the mass of the first structure 20 plus the mass of the wind power generator equipment 2 and the fluid effect such as the added mass of water. X is the displacement of the wave, x ₁ is the displacement of the second structure 30, x ₂ is the displacement of the intermediate structure 40, and x ₃ is the displacement of the first structure 20. _k1 is the spring constant of the second imaginary elastic body 12, _k2 is the spring constant of the second elastic body 60, _k3 is the spring constant of the first elastic body 50, and _k4 is the spring constant of the first imaginary elastic body 11. _c1 is the damping coefficient of the second structure 30 against waves, _c2 is the damping coefficient for the relative displacement between the second structure 30 and the intermediate structure 40, _c3 is the damping coefficient for the relative displacement between the first structure 20 and the intermediate structure 40, and _c4 is the damping coefficient of the first structure 20 against waves. _ms3 is the inertial mass of the first rotating body 90, i.e., the inertial mass due to the first conversion rotor 71 and the first generator rotor 81.

ここで、ｃ_ｓは第１装置発電機８０の反抗トルクによる減衰係数であり、第１装置発電機８０の仕様によって決定される。 The equation of motion of the dynamic model shown in FIG. 3 is an equation of motion for a three-degree-of-freedom system, and is expressed as shown in the following equation (2).

Here, c _s is a damping coefficient due to the reaction torque of the first device generator 80 and is determined by the specifications of the first device generator 80.

In a typical structure, the mass matrix on the left side of the equation of motion is a diagonal matrix. In contrast, in equation (2), the off-diagonal term contains "-m _S3 ". This means that mass coupling occurs between the first structure 20 and the intermediate structure 40.

ここで、ε_１は上述した第１変速装置７４の増速率であり、Ｉ_ｓ３は第１発電機回転子８１の慣性モーメントと第１変換回転子７１の慣性モーメントの合成値である。ｒ_３は、第１変速歯車７５のピッチ円半径である。このように、第１発電機回転子８１および第１変換回転子７１は、第１構造体２０と中間構造体４０との間の相対変位による振動を低減する慣性質量要素として機能する第１回転体９０を構成している。すなわち、第１発電機回転子８１の慣性モーメントと第１変換回転子７１の慣性モーメントは、第１構造体２０と中間構造体４０との間の並進運動に対して質量の連成を生じる。 The inertial mass m _S3 is expressed by the following equation.

Here, ε ₁ is the speed increase rate of the first speed change device 74 described above, I _s3 is a composite value of the moment of inertia of the first generator rotor 81 and the moment of inertia of the first conversion rotor 71, and _{r 3} is the pitch circle radius of the first speed change gear 75. In this way, the first generator rotor 81 and the first conversion rotor 71 constitute the first rotating body 90 that functions as an inertial mass element that reduces vibration caused by relative displacement between the first structure 20 and the intermediate structure 40. That is, the moment of inertia of the first generator rotor 81 and the moment of inertia of the first conversion rotor 71 cause mass coupling with respect to the translational motion between the first structure 20 and the intermediate structure 40.

The inertial mass m _S3 accumulates kinetic energy that is transferred from mass m ₂ to mass m _3. This kinetic energy T is expressed by the following formula:

Therefore, the first device generator 80 converts the stored kinetic energy T into electrical energy and blocks vibration transmission between masses _m2 and _m3 with the kinetic energy T. By solving equation (2) while ignoring damping, the cutoff frequency _fs3 at which _x3 is minimized is expressed as follows:

Here, α ₃ , β ₃ , and γ ₃ are expressed by the following formula.

As shown in equations (5) to (8), the cutoff frequency _fs3 can be adjusted by the inertial mass _mS3 . The inertial mass _mS3 can be adjusted by the speed increase rate _ε1 of the first transmission 74 as shown in equation (3).

Next, we will explain the frequency response of the wave power generation device 10 according to this embodiment.

First, as a comparative example, we will explain the frequency response of a typical wave power generation device 210.

As shown in FIG. 4, a typical wave power generation device 210 includes a first structure 220 floating on the ocean, a second structure 230, an elastic body 240, and a device generator 250. FIG. 4 is a schematic cross-sectional view showing a typical wave power generation device.

The first structure 220 includes a first floating body 221, a spoke 222, and a first cavity 223. The first floating body 221 may be configured similarly to the first floating body 21 shown in FIG. 2. The first floating body 221 is elastically supported with respect to the stationary system by a first imaginary elastic body 211 having a spring constant k _4. The spoke 222 is connected to the first floating body 221. The spoke 222 extends horizontally from the first floating body 221 to a position above the second structure 230. The spoke 222 is configured as a support frame capable of supporting a cylindrical support 251 of the device generator 250. A sleeve 224 is fixed to the spoke 222. The first cavity 223 is formed in the sleeve 224. The first cavity 223 is formed in a cylindrical shape so as to extend along the second central axis L2. The first cavity 223 penetrates the sleeve 224. The first cavity 223 is located above the second structure 230. A second rod 232 (described later) is inserted into the first cavity 223. The diameter of the first cavity 223 is larger than the outer diameter of the second rod 232.

A plurality of rollers 225 may be attached to the inner peripheral surface of the sleeve 224. The rollers 225 are capable of rolling on the outer peripheral surface of the second rod 232. This allows smooth relative displacement of the second rod 232 with respect to the sleeve 224. A guide rail (not shown) extending in the axial direction d along the second central axis L2 may be attached to the outer peripheral surface of the second rod 232.

The second structure 230 is capable of being displaced relative to the first structure 220, similar to the second structure 30 shown in FIG. 2. The second structure 230 includes a second floating body 231 and a second rod 232. The second floating body 231 may be configured similarly to the second floating body 231 shown in FIG. 2. The second floating body 231 is elastically supported with respect to the stationary system by a second imaginary elastic body 212 having a spring constant k _1. The second floating body 231 shown in FIG. 4 does not have a cavity. The second rod 232 extends upward from the second floating body 231. The second rod 232 is formed in a cylindrical shape so as to extend along the second central axis L2. The second rod 232 is inserted into and penetrates the first cavity 223 described above.

The elastic body 240 elastically connects the first structure 220 and the second structure 230. More specifically, the elastic body 240 connects the sleeve 224 and the second floating body 231. The elastic body 240 has a spring constant _k2 .

The device generator 250 is configured as an electromagnetic induction type linear generator. The device generator 250 includes a cylindrical support 251, a plurality of coils 252, and a plurality of permanent magnets 253 installed on the second rod 232. The cylindrical support 251 is supported by the spokes 222 and extends upward from the spokes 222. The cylindrical support 251 is formed in a cylindrical shape so as to extend along the second central axis L2, and the second rod 232 is inserted into the space inside the cylindrical support 251. The coil 252 is wound around the cylindrical support 251. The permanent magnet 253 is attached to the second rod 232. The permanent magnet 253 is formed in a ring shape so as to cover the outer circumferential surface. Each permanent magnet 253 is positioned at a position corresponding to the coil 252. The wave power generation device 210 shown in FIG. 4 does not include a conversion rotor and a generator rotor that function as inertial mass elements as shown in FIG. 2.

In the wave power generation device 210 shown in FIG. 4, when the first float 221 and the second float 231 are displaced relative to each other, the magnetic flux passing through each coil 252 changes, and an induced electromotive force is generated. In this way, the device generator 250 can generate electricity. The magnitude of the induced electromotive force is proportional to the relative speed between the first float 221 and the second float 231.

The wave power generation device 210 shown in FIG. 4 is modeled as the mechanical model shown in FIG. 5.

In FIG. 5, _m1 is the mass of the second structure 230, and _m2 is the mass of the first structure 220. More specifically, _m1 is the mass obtained by adding the mass of the second structure 230, the mass of the permanent magnet 253 of the device generator 250, and fluid effects such as additional mass due to water. _m2 is the mass obtained by adding the mass of the cylindrical support 251 and the coil 252 of the device generator 250, the mass of the wind power generation facility 2, and fluid effects such as additional mass due to water to the mass of the first structure 220. X is the displacement of the wave, _x1 is the displacement of the second structure 230, and _x2 is the displacement of the first structure 220. _k1 is the spring constant of the second virtual elastic body 212, _k2 is the spring constant of the elastic body 240, and _k4 is the spring constant of the first virtual elastic body 211. _c1 is the damping coefficient of the second structure 230 for waves, _c2 is the damping coefficient for the relative displacement between the first structure 220 and the second structure 230, and _c4 is the damping coefficient of the first structure 220 for waves.

The frequency response results of the wave power generation device 210 shown in Fig. 4 are shown in Fig. 6. The horizontal axis indicates the excitation frequency (or wave frequency), and the vertical axis indicates the response magnification. The response magnification of the second structure 230 is represented by _x1 /X, and the response magnification of the first structure 220 is represented by _x2 /X.

As shown in Fig. 6, the relative displacement between the first structure 220 and the second structure 230 is large when the excitation frequency is in the range of 0.05 Hz to 0.5 Hz. Since the frequency of the displacement X of ocean waves is in the range of approximately 0.05 Hz to 0.5 Hz, it can be seen that the wave power generation device 210 in Fig. 4 can increase the amount of power generation. The relative displacement is largest when the excitation frequency is around 0.5 Hz, which corresponds to the natural frequency. However, the response magnification ( _x2 /X) of the first structure 220 is also large.

In contrast, the frequency response results of the wave power generator 10 according to this embodiment are shown in Fig. 7. The horizontal axis indicates the excitation frequency, and the vertical axis indicates the response magnification. The response magnification of the second structure 30 is represented by _x1 /X, the response magnification of the intermediate structure 40 is represented by _x2 /X, and the response magnification of the first structure 20 is represented by _x3 /X.

As shown in Fig. 7, in the excitation frequency range of 0.05 Hz to 0.5 Hz, the response magnification ( _x3 /X) of the first structure 20 is smaller than the response magnification ( _x2 /X) of the first structure 220 shown in Fig. 6. This shows that the propagation of vibration from the intermediate structure 40 to the first structure 20 is suppressed. Therefore, the vibration of the first structure 20 is suppressed, and the displacement of the first structure 20 is reduced.

Since the response magnification ( _x2 /X) of the intermediate structure 40 is increased in the same excitation frequency range, it is possible to increase the relative displacement between the first structure 20 and the intermediate structure 40. This makes it possible to increase the amount of power generation, and therefore the amount of power generation can be effectively increased.

Incidentally, in the mass matrix of the above-mentioned equation (2), the off-diagonal terms include "-m _S3 " which indicates the inertial mass of the first generator rotor 81 and the first conversion rotor 71. As a result, the cut-off frequency f _s3 can be found as shown in the above-mentioned equation (5), and a vibration system in which the cut-off frequency f _s3 exists is obtained. When the excitation frequency is the cut-off frequency, the vibration of the first structure 20 can be further suppressed and the amount of power generation can be further increased.

More specifically, as shown in Fig. 7, the response magnification of the first structure 20 is small when the excitation frequency is around 0.62 Hz, which corresponds to the above-mentioned cut-off frequency _fs3 . This makes it possible to suppress the propagation of vibration from the intermediate structure 40 to the first structure 20, and further suppress the vibration of the first structure 20. In addition, the relative displacement between the first structure 20 and the intermediate structure 40 can be further increased. This makes it possible to further increase the amount of power generation.

The cut-off frequency can be adjusted according to the exciting frequency by changing the above-mentioned speed-up rate ε ₁ of the first transmission 74. Furthermore, when a flywheel is attached to the first generator rotor 81, the cut-off frequency can also be adjusted according to the exciting frequency by changing the moment of inertia of the flywheel. This makes it possible to effectively suppress the vibration of the first structure 20.

Thus, according to this embodiment, the intermediate structure 40, which is elastically connected to each of the first structure 20 and the second structure 30 floating on the ocean, is capable of relative displacement with respect to each of the first structure 20 and the second structure 30. The relative displacement between the first structure 20 and the intermediate structure 40 is converted into a rotational displacement of the first conversion rotor 71 of the first conversion mechanism 70. The rotational displacement of the first conversion rotor 71 rotates the first generator rotor 81, and the first device generator 80 generates power. The first generator rotor 81 and the first conversion rotor 71 constitute a first rotating body 90 that functions as an inertial mass element that reduces vibration propagation from the intermediate structure 40 to the first structure 20. This makes it possible to suppress vibration of the first structure 20. Therefore, the relative displacement between the first structure 20 and the intermediate structure 40 can be increased, and the amount of power generation can be increased. In addition, as described above, since the propagation of vibration from the intermediate structure 40 to the first structure 20 is suppressed, the vibration of the first structure 20 can be suppressed. As a result, it is possible to suppress vibrations that adversely affect the control of the wind turbine generator body 4, and to increase the amount of power generated by wave force.

Furthermore, according to this embodiment, the first device generator 80 and the first conversion rotor 71 are supported by the intermediate structure 40. This makes it possible to increase the above-mentioned mass _m2 including the mass of the intermediate structure 40 in the vibration system of the wave power generation device 10. This makes it possible to increase the response magnification of the intermediate structure 40 and to increase the relative displacement between the first structure 20 and the intermediate structure 40. As a result, it is possible to increase the amount of power generated by wave force.

According to this embodiment, the first structure 20 includes a first rod 23 inserted into the intermediate cavity 42 of the intermediate structure 40, and the first conversion mechanism 70 includes a first rack rail 72 provided on the first rod 23 and extending in the axial direction d, and a first pinion gear 73 meshing with the teeth of the first rack rail 72. This allows the relative translational displacement of the first structure 20 and the intermediate structure 40 to be converted into the rotational displacement of the first conversion rotor 71 and the first generator rotor 81. In addition, the first rod 23 provided with the first rack rail 72 can be used as a component of the first structure 20. When the first structure 20 is more stable than the second structure 30, it is possible to suppress the first rod 23 from tilting, and to suppress damage to the wave power generation device 10.

In addition, according to this embodiment, the first conversion rotor 71 includes a first speed change gear 75 interposed between the first rack rail 72 and the first pinion gear 73. This allows the rotation speed of the first pinion gear 73 to be adjusted by the first speed change gear 75, and the amount of power generated by the first device generator 80 to be adjusted. In addition, by adjusting the number of teeth of the first speed change gear 75, the speed increase rate, which is the ratio of the rotation speeds of the first speed change gear 75 and the first pinion gear 73, can be adjusted according to the excitation vibration frequency, and the cutoff vibration frequency can be adjusted. Therefore, the vibration of the first structure 20 can be effectively suppressed, and the amount of power generated by wave force can be effectively increased.

In the above-described embodiment, an example has been described in which the first conversion mechanism 70 converts the relative displacement between the first structure 20 and the intermediate structure 40 into the rotational displacement of the first conversion rotor 71. However, this is not limited to the above. For example, the first conversion mechanism 70 may convert the relative displacement between the second structure 30 and the intermediate structure 40 into the rotational displacement of the first conversion rotor 71. In this case, the first conversion mechanism 70 may be configured in the same manner as the second conversion mechanism 100 shown in FIG. 12, which will be described later.

In the above-described embodiment, an example has been described in which the first pinion gear 73 meshes with the first rack rail 72 via the first speed change gear 75. However, this is not limited to this. For example, the first speed change gear 75 does not have to be interposed between the first pinion gear 73 and the first rack rail 72. In this case, the first pinion gear 73 meshes directly with the first rack rail 72.

Second Embodiment
Next, a wave power generation device and an offshore wind power generation system according to a second embodiment will be described with reference to Figs.

The second embodiment shown in Figures 8 to 10 differs mainly in that the wave power generation device includes a plurality of second structures, a plurality of intermediate structures, a plurality of first conversion mechanisms, and a plurality of first device generators, and the other configurations are substantially the same as those of the first embodiment shown in Figures 1 to 3 and 7. Note that in Figures 8 to 10, the same parts as those in the first embodiment shown in Figures 1 to 3 and 7 are given the same reference numerals and detailed explanations are omitted. Figure 8 is a schematic cross-sectional view showing a wave power generation device according to the second embodiment, and Figure 9 is a top view of Figure 8. The wind power generation facility 2 is omitted in Figures 8 and 9.

As shown in Figures 8 and 9, the wave power generation device 10 according to this embodiment includes a plurality of second structures 30, a plurality of intermediate structures 40, a plurality of first conversion mechanisms 70, and a plurality of first device generators 80. In this embodiment, the number of second structures 30, the number of intermediate structures 40, the number of first conversion mechanisms 70, and the number of first device generators 80 are each four.

Each second structure 30 is elastically connected to the first structure 20 via a corresponding intermediate structure 40. Each second structure 30 is configured to be independently displaceable relative to the first structure 20. The second structures 30 are configured separately and vibrate independently. When viewed from above as shown in FIG. 9, the second structures 30 may be evenly arranged along the circumferential direction centered on the first floating body 21 of the first structure 20.

Each intermediate structure 40 is elastically connected to each of the first structure 20 and the corresponding second structure 30. Each intermediate structure 40 is configured to be displaceable relative to each of the first structure 20 and the corresponding second structure 30. The intermediate structures 40 are configured separately and vibrate independently. When viewed from above as shown in FIG. 9, the intermediate structures 40 may be evenly arranged along the circumferential direction centered on the first floating body 21. The intermediate structures 40 are arranged above the corresponding second structures 30.

Each first conversion mechanism 70 is configured to convert the relative displacement between the first structure 20 and the corresponding intermediate structure 40 into a rotational displacement of the first conversion rotor 71. The first conversion rotor 71 of each first conversion mechanism 70 is supported by the corresponding intermediate structure 40.

Each first device generator 80 is configured such that the first generator rotor 81 rotates with the rotational displacement of the first conversion rotor 71 of the corresponding first conversion mechanism 70 to generate electricity. Each first device generator 80 is supported by the corresponding intermediate structure 40 together with the corresponding first conversion rotor 71.

As shown in FIG. 9, when viewed from above, the second structure 30 and the intermediate structure 40 are each arranged along the circumferential direction centered on the first structure 20. More specifically, the second structure 30 and the intermediate structure 40 are evenly arranged in the circumferential direction.

For example, when viewed from above, the second structure 30 and the intermediate structure 40 may be located at positions that are point symmetrical about the first central axis L1 of the first structure 20. The wave power generation device 10 according to this embodiment includes four second structures 30 and intermediate structures 40. In this case, as shown in FIG. 9, the second structures 30 and intermediate structures 40 may be evenly arranged at 90° intervals. Two of the four second structures 30 are arranged diagonally, i.e., on the opposite side to the first structure 20. In other words, when two diagonally arranged second structures 30 are considered as one pair, two pairs of second structures 30 are arranged around the first structure 20.

The first conversion mechanism 70 and the first device generator 80 are supported by the corresponding intermediate structure 40. The first conversion mechanism 70 and the first device generator 80 are arranged radially outward relative to the corresponding first rod 23. As shown in FIG. 9, the first device generator 80 is arranged in a clockwise direction relative to the corresponding first pinion gear 73. More specifically, the first device generator 80 arranged on the right side in FIG. 9 is arranged below the corresponding first pinion gear 73, and the first device generator 80 arranged on the lower side is arranged on the left side relative to the corresponding first pinion gear 73. The first device generator 80 arranged on the left side is arranged above the corresponding first pinion gear 73, and the first device generator 80 arranged on the upper side is arranged to the right of the corresponding first pinion gear 73.

As described above, the first device generators 80 are arranged in point symmetry. The couple forces generated in the first generator rotors 81 of each first device generator 80 have the same magnitude but act in opposite directions. This makes it possible to suppress rolling (rotational vibrations around the first central axis L1 of the wave power generation device 10) and pitching (rotational vibrations around an axis perpendicular to the first central axis L1 of the wave power generation device 10) that occur in the wave power generation device 10. In other words, the rotational directions of the rotational forces generated by the couple forces generated in each first generator rotor 81 are opposite to each other between the two first generator rotors 81 located diagonally. Therefore, the rotational forces generated by the couple forces generated in each first generator rotor 81 can be offset, and rolling and pitching can be suppressed from being excited in the wave power generation device 10.

Thus, according to this embodiment, the wave power generation device 10 includes a plurality of second structures 30, a plurality of intermediate structures 40, a plurality of first conversion mechanisms 70, and a plurality of first device generators 80. The intermediate structures 40 are capable of relative displacement with respect to the first structures 20 and the corresponding second structures 30. The first conversion mechanisms 70 convert the relative displacement between the first structures 20 and the corresponding intermediate structures 40 into a rotational displacement of the first conversion rotor 71, and power is generated by the corresponding first device generators 80. This allows power to be generated by the multiple first device generators 80. This allows the amount of power generated by wave force to be increased.

In addition, according to this embodiment, when viewed from above, the second structure 30, the intermediate structure 40, the first conversion mechanism 70, and the first device generator 80 are each arranged along the circumferential direction centered on the first structure 20. This makes it possible to cancel out the rotational force caused by the couple generated in the first generator rotor 81 of each first device generator 80. This makes it possible to suppress the excitation of rolling or pitching in the wave power generation device 10, and to suppress adverse effects on the control of the wind power generator main body 4.

In the above-described embodiment, an example has been described in which the number of second structures 30, the number of intermediate structures 40, the number of first conversion mechanisms 70, and the number of first device generators 80 are each four. However, this is not limited to this, and the number of second structures 30, the number of intermediate structures 40, the number of first conversion mechanisms 70, and the number of first device generators 80 may be two or three as long as they are multiple, and are arbitrary. Even if the number of these is an odd number, such as three, if they are evenly arranged along the circumferential direction centered on the first floating body 21, the rotational force generated by the couple generated in each first generator rotor 81 can be offset.

In the above-described embodiment, the second structures 30 are constructed separately, and each second structure 30 vibrates independently. However, the present invention is not limited to this. For example, as shown in FIG. 10, a plurality of second structures 30 may be connected to each other and integrated. FIG. 10 is a top view showing a modified example of FIG. 9. By connecting a plurality of second structures 30 in this way, the mechanical strength against waves with a small vibration frequency can be improved. For example, the second floating bodies 31 of the second structures 30 adjacent to each other in the circumferential direction may be connected by a structure connecting portion 95. In this case, the plurality of second structures 30 and the plurality of structure connecting portions 95 may be formed in a ring shape as a whole when viewed from above. Alternatively, although not shown, the intermediate structures 40 may be connected to each other instead of the second structures 30. Furthermore, the second floating bodies 31 of the second structures 30 adjacent to each other in the circumferential direction may be connected by a structure connecting portion 95, and the intermediate structures 40 may be connected to each other.

Third Embodiment
Next, a wave power generator and an offshore wind power generation system according to a third embodiment will be described with reference to FIG.

The third embodiment shown in FIG. 11 differs mainly in that the first converter rotor and the first device generator are supported by the first structure, and the other configurations are substantially the same as those of the first embodiment shown in FIG. 1 to FIG. 3 and FIG. 7. In FIG. 11, the same parts as those in the first embodiment shown in FIG. 1 to FIG. 3 and FIG. 7 are given the same reference numerals and detailed explanations are omitted. FIG. 11 is a schematic cross-sectional view showing a wave power generation device according to the third embodiment. The wind power generation facility 2 is omitted in FIG. 11.

As shown in FIG. 11, in this embodiment, the first structure 20 includes a first cavity 25. The first cavity 25 is formed in a sleeve 26 fixed to the spoke 22 and penetrates the sleeve 26. The sleeve 26 protrudes downward from the spoke 22. The first cavity 25 is formed in a cylindrical shape so as to extend along the second central axis L2. The first cavity 25 is located above an intermediate main body portion 45 of the intermediate structure 40, which will be described later. A first intermediate rod 46, which will be described later, is inserted into the first cavity 25. The diameter of the first cavity 25 is larger than the outer diameter of the first intermediate rod 46.

A plurality of rollers 27 may be attached to the inner peripheral surface of the sleeve 26. The rollers 27 may be arranged at intervals in the axial direction d along the second central axis L2, or may be arranged at intervals in the circumferential direction. The rollers 27 are capable of rolling on the outer peripheral surface of the first intermediate rod 46. This allows the first intermediate rod 46 to be smoothly displaced relative to the sleeve 26. A guide rail (not shown) extending in the axial direction d may be attached to the outer peripheral surface of the first intermediate rod 46. This prevents the intermediate structure 40 from rotating about the second central axis L2 relative to the first structure 20. In addition, the relative displacement of the first intermediate rod 46 with respect to the sleeve 26 can be guided in the axial direction d.

As in the first embodiment shown in FIG. 2, a second cavity 32 is formed in the second floating body 31 of the second structure 30. The second cavity 32 is located below the intermediate main body portion 45 described below. A second intermediate rod 47 described below is inserted into the second cavity 32. The diameter of the second cavity 32 is larger than the outer diameter of the second intermediate rod 47.

A plurality of rollers 33 may be attached to the inner circumferential surface of the second float 31, as in the first embodiment shown in FIG. 2. The rollers 33 are capable of rolling on the outer circumferential surface of the second intermediate rod 47. A guide rail (not shown) extending in the axial direction d may be attached to the outer circumferential surface of the second intermediate rod 47.

The intermediate structure 40 includes an intermediate body portion 45, a first intermediate rod 46, and a second intermediate rod 47. The intermediate body portion 45 is located below the first cavity portion 25 and above the second cavity portion 32. The intermediate body portion 45 extends further horizontally than the first intermediate rod 46 and the second intermediate rod 47.

The first intermediate rod 46 extends upward from the intermediate main body portion 45. The first intermediate rod 46 is formed in a cylindrical shape so as to extend along the second central axis L2. The first intermediate rod 46 is inserted into the first cavity portion 25 and penetrates the first cavity portion 25.

The second intermediate rod 47 extends downward from the intermediate main body portion 45. The second intermediate rod 47 is formed in a cylindrical shape so as to extend along the second central axis L2. The second intermediate rod 47 is inserted into the second hollow portion 32. This allows the second intermediate rod 47 to restrict the movement of the second structure 30 in a direction perpendicular to the second central axis L2.

The first elastic body 50 connects the sleeve 26 to the intermediate body portion 45. The second elastic body 60 connects the second float 31 to the intermediate body portion 45.

The first rack rail 72 of the first conversion mechanism 70 is provided on the first intermediate rod 46. More specifically, the first rack rail 72 is attached to the outer circumferential surface of the first intermediate rod 46. The first rack rail 72 extends in the axial direction d and can be inserted into the first cavity 25.

The first pinion gear 73 is supported by the first structure 20. More specifically, the first pinion gear 73 is rotatably supported by the spokes 22. The first transmission 74 is supported by the spokes 22 of the first structure 20. The first transmission gear 75 is rotatably supported by the spokes 22.

The first device generator 80 is supported by the first structure 20. More specifically, the first device generator 80 is supported by the spokes 22. The first generator rotor 81 is rotatably supported by the spokes 22.

As described above, according to this embodiment, the first device generator 80 and the first conversion rotor 71 are supported by the first structure 20. This allows the first pinion gear 73 and the first device generator 80 to be supported by the first structure 20, which is designed to suppress vibration. As a result, the transmission of vibration to the first device generator 80 can be suppressed, and the reliability and maintainability of the first device generator 80 can be improved.

In addition, according to this embodiment, the first structure 20 includes a first cavity 25 extending along the second central axis L2, and the intermediate structure 40 includes a first intermediate rod 46 extending along the second central axis L2. The first intermediate rod 46 is inserted into the first cavity 25. The first rack rail 72 of the first conversion mechanism 70 is provided on the first intermediate rod 46. This allows the relative translational displacement of the first structure 20 and the intermediate structure 40 to be converted into the rotational displacement of the first conversion rotor 71 and the first generator rotor 81.

(Fourth embodiment)
Next, a wave power generator and an offshore wind power generation system according to a fourth embodiment will be described with reference to Figs.

The fourth embodiment shown in Figures 12 to 14 differs mainly in that the wave power generation device is equipped with a second conversion mechanism including a second conversion rotor, and a second device generator that generates power through the rotational displacement of the second conversion rotor, and the other configurations are substantially the same as those of the third embodiment shown in Figure 11. Note that in Figures 12 to 14, the same parts as those in the third embodiment shown in Figure 11 are given the same reference numerals and detailed explanations are omitted. Figure 12 is a schematic cross-sectional view showing a wave power generation device according to the fourth embodiment. In Figure 12, the wind power generation facility 2 is omitted.

As shown in FIG. 12, the wave power generation device 10 according to this embodiment further includes a second conversion mechanism 100 and a second device generator 110.

The second conversion mechanism 100 includes a second conversion rotor 101. The second conversion mechanism 100 according to this embodiment is configured to convert the relative displacement between the second structure 30 and the intermediate structure 40 into a rotational displacement of the second conversion rotor 101.

More specifically, the second conversion mechanism 100 includes the above-mentioned second conversion rotor 101 and the second rack rail 102.

The second rack rail 102 is an example of a second rack. The second rack rail 102 is provided on the second intermediate rod 47. More specifically, the second rack rail 102 is attached to the outer circumferential surface of the second intermediate rod 47. The second rack rail 102 extends in the axial direction d. The second rack rail 102 can be inserted into the second hollow portion 32 of the second floating body 31.

The second conversion rotor 101 includes a second pinion gear 103 and a second speed change gear 105.

The second pinion gear 103, together with the second speed gear 105, constitutes the second conversion rotor 101 described above. The second pinion gear 103 meshes with the teeth of the second rack rail 102 via the second speed gear 105, and converts the translational relative displacement in the axial direction d between the second structure 30 and the intermediate structure 40 into a rotational displacement. The second pinion gear 103 may be coaxially connected to the second generator rotor 111 described later.

The second pinion gear 103 is supported by the second structure 30. More specifically, the second pinion gear 103 is rotatably supported by the second floating body 31. A support frame 34 may be attached to the second floating body 31, and the second pinion gear 103 may be rotatably supported by the support frame 34 by a bearing (not shown). The rotation axis of the second pinion gear 103 may coincide with the rotation axis of the second generator rotor 111. Alternatively, the rotation axis of the second pinion gear 103 may be disposed in a direction perpendicular to the rotation axis of the second speed gear 115 described later when viewed from above. The support frame 34 is located at the upper end of the second floating body 31 and is supported by the second floating body 31. The support frame 34 extends in the horizontal direction (perpendicular to the axial direction d).

The second speed change gear 105 is interposed between the second rack rail 102 and the second pinion gear 103. The second speed change gear 105 and the second pinion gear 103 constitute the second conversion rotor 101. The number of teeth of the second speed change gear 105 may be variable by the second speed change device 104. The second speed change device 104 can be configured in the same manner as the first speed change device 74 shown in FIG. 2 etc., so a detailed description is omitted here. The second speed change device 104 may include a protective cover 106 that covers the second speed change gear 105. The second speed change device 104 is supported by the second structure 30. More specifically, the second speed change device 104 is supported by the second floating body 31 or the support frame 34. The second speed change gear 105 is rotatably supported by a bearing (not shown) on the support frame 34. The rotation axis of the second speed gear 105 may be parallel to the rotation axis of the second pinion gear 103.

The second device generator 110 includes a second generator rotor 111. The second device generator 110 is configured such that the second generator rotor 111 rotates with the rotational displacement of the second conversion rotor 101 to generate power. The second device generator 110 is supported by the second floating body 31 or the support frame 34 of the second structure 30. The second generator rotor 111 has a rotation axis along the horizontal direction.

The second generator rotor 111 and the second conversion rotor 101 described above constitute a second rotating body 120 that functions as an inertial mass element that reduces vibration transmission from the intermediate structure 40 to the second structure 30. In this embodiment, the second rotating body 120 is constituted by the second generator rotor 111, the second pinion gear 103, and the second speed gear 105.

As shown in FIG. 12, an elastic body connecting part 48 to which the second elastic body 60 is connected may be fixed to the second intermediate rod 47. In this case, the second elastic body 60 connects the elastic body connecting part 48 fixed to the second intermediate rod 47 to the second float 31. This allows the intermediate main body part 45 to be moved away from the second float 31, and ensures installation space for the second rack rail 102. The spokes 22 of the first structure 20 may be connected to the upper part of the first float 21.

The wave power generation device 10 according to this embodiment configured as described above is modeled as a dynamic model shown in Fig. 13. m _s2 shown in Fig. 13 is the inertial mass of the second rotating body 120, that is, the inertial mass of the second converter rotor 101 and the second generator rotor 111. In this embodiment, m ₁ is the mass obtained by adding the fluid effect such as the additional mass of water, the mass of the stator of the second device generator 110, and the mass of the fixed side of the second speed change device 104 to the mass of the second structure 30.

ここで、ｃ_ｓ３は第１装置発電機８０の反抗トルクによる減衰係数であり、第１装置発電機８０の仕様によって決定される。ｃ_ｓ２は第２装置発電機１１０の反抗トルクによる減衰係数であり、第２装置発電機１１０の仕様によって決定される。 The equation of motion of the dynamic model shown in FIG. 13 is expressed as shown in the following equation (9).

Here, _cs3 is a damping coefficient due to the reaction torque of the first device generator 80 and is determined by the specifications of the first device generator 80. _cs2 is a damping coefficient due to the reaction torque of the second device generator 110 and is determined by the specifications of the second device generator 110.

ここで、ε_２は第２変速装置１０４の増速率であり、Ｉ_ｓ２は第２発電機回転子１１１の慣性モーメントと第２変換回転子１０１の慣性モーメントの合成値である。ｒ_２は、第２変速歯車１０５のピッチ円半径である。このように、第２発電機回転子１１１および第２変換回転子１０１は、第２構造体３０と中間構造体４０との間の相対変位による振動を低減する慣性質量要素として機能する第２回転体１２０を構成している。すなわち、第２発電機回転子１１１の慣性モーメントと第２変換回転子１０１の慣性モーメントは、第２構造体３０と中間構造体４０との間の並進運動に対して質量の連成を生じる。 The inertial mass m _S2 is expressed by the following equation.

Here, _ε2 is the speed increase rate of the second speed change device 104, I _s2 is the composite value of the moment of inertia of the second generator rotor 111 and the moment of inertia of the second conversion rotor 101, and _r2 is the pitch circle radius of the second speed change gear 105. In this way, the second generator rotor 111 and the second conversion rotor 101 constitute the second rotating body 120 that functions as an inertial mass element that reduces vibration caused by relative displacement between the second structure 30 and the intermediate structure 40. That is, the moment of inertia of the second generator rotor 111 and the moment of inertia of the second conversion rotor 101 cause mass coupling with respect to the translational motion between the second structure 30 and the intermediate structure 40.

The inertial mass m _S3 is expressed by the above-mentioned formula (3). As described above, the first generator rotor 81 and the first conversion rotor 71 configure the first rotating body 90 that functions as an inertial mass element that reduces vibration caused by relative displacement between the first structure 20 and the intermediate structure 40. That is, the inertia moment of the first generator rotor 81 and the inertia moment of the first conversion rotor 71 cause mass coupling with respect to the translational motion between the first structure 20 and the intermediate structure 40.

The inertial mass m _S2 of the second generator rotor 111 of the second device generator 110 accumulates kinetic energy T ₁ that is transferred from mass m ₁ to mass m _2. This kinetic energy T ₁ is expressed by the following equation.

The inertial mass m _S3 of the first generator rotor 81 of the first device generator 80 accumulates kinetic energy T ₂ that is transferred from mass m ₂ to mass m _3. This kinetic energy T ₂ is expressed by the following equation.

The first device generator 80 converts the stored kinetic energy _T2 into electrical energy and blocks vibration transmission between masses _m2 and _m3 with the kinetic energy _T2 . The second device generator 110 converts the stored kinetic energy _T1 into electrical energy and blocks vibration transmission between masses _m1 and _m2 with the kinetic energy _T1 . By solving equation (9) while ignoring damping, the cutoff frequency _fs3 at which _x3 is minimized is expressed as follows:

Here, α ₃ , β ₃ , and γ ₃ are expressed by the following formula.

As shown in equations (13) to (16), the cutoff frequency _fs3 can be adjusted by the inertial masses _mS2 and _mS3 . The inertial mass _mS2 can be adjusted by the speed increase rate _ε2 of the second transmission 104 as shown in equation (10). The inertial mass _mS3 can be adjusted by the speed increase rate _ε1 of the first transmission 74 as shown in equation (3).

The vibration frequency response result of the wave power generator 10 according to this embodiment is shown in Fig. 14. As shown in Fig. 14, the response magnification ( _x3 /X) of the first structure 20 is smaller. This shows that the propagation of vibration from the intermediate structure 40 to the first structure 20 is further suppressed than the response magnification shown in Fig. 7. Therefore, the vibration of the first structure 20 is further suppressed, and the displacement of the first structure 20 is further reduced.

In this manner, according to the present embodiment, the relative displacement between the first structure 20 and the intermediate structure 40 is converted into the rotational displacement of the first conversion rotor 71 of the first conversion mechanism 70. The rotational displacement of the first conversion rotor 71 rotates the first generator rotor 81, and the first device generator 80 generates power. The first generator rotor 81 and the first conversion rotor 71 constitute a first rotating body 90 that functions as an inertial mass element that reduces the vibration propagation from the intermediate structure 40 to the first structure 20. This makes it possible to suppress the vibration of the first structure 20. Therefore, it is possible to increase the relative displacement between the first structure 20 and the intermediate structure 40, and to increase the amount of power generation. In addition, as described above, since the propagation of vibration from the intermediate structure 40 to the first structure 20 is suppressed, the vibration of the first structure 20 can be suppressed. As a result, it is possible to suppress vibrations that adversely affect the control of the wind power generator main body 4, and to increase the amount of power generation by wave force.

In addition, according to this embodiment, the relative displacement between the second structure 30 and the intermediate structure 40 is converted into the rotational displacement of the second conversion rotor 101 of the second conversion mechanism 100. The rotational displacement of the second conversion rotor 101 rotates the second generator rotor 111, and the second device generator 110 generates power. The second generator rotor 111 and the second conversion rotor 101 constitute a second rotating body 120 that functions as an inertial mass element that reduces vibration propagation from the intermediate structure 40 to the second structure 30. This makes it possible to suppress the vibration of the second structure 30. Therefore, the relative displacement between the second structure 30 and the intermediate structure 40 can be increased, and the amount of power generation can be increased. In addition, as described above, since the propagation of vibration from the intermediate structure 40 to the second structure 30 is suppressed, the vibration of the second structure 30 can be suppressed. As a result, it is possible to suppress vibrations that adversely affect the control of the wind power generator main body 4, and to increase the amount of power generation by wave force.

Furthermore, according to this embodiment, the second device generator 110 and the second conversion rotor 101 are supported by the second structure 30. This makes it possible to increase the above-mentioned mass _m1 including the mass of the second structure 30 in the vibration system of the wave power generation device 10. This makes it possible to increase the response magnification of the second structure 30 and to increase the relative displacement between the second structure 30 and the intermediate structure 40. As a result, it is possible to increase the amount of power generated by wave force.

Furthermore, according to this embodiment, the second structure 30 includes a second cavity 32 extending along the second central axis L2, and the intermediate structure 40 includes a second intermediate rod 47 extending along the second central axis L2. The second intermediate rod 47 is inserted into the second cavity 32. The second rack rail 102 of the second conversion mechanism 100 is provided on the second intermediate rod 47. This makes it possible to convert the translational relative displacement between the second structure 30 and the intermediate structure 40 into a rotational displacement.

In addition, according to this embodiment, the second conversion rotor 101 includes a second speed change gear 105 interposed between the second rack rail 102 and the second pinion gear 103. As a result, the rotation speed of the second pinion gear 103 can be adjusted by the second speed change gear 105, and the amount of power generated by the second device generator 110 can be adjusted. In addition, by adjusting the number of teeth of the second speed change gear 105, the speed increase rate, which is the ratio of the rotation speeds of the second speed change gear 105 and the second pinion gear 103, can be adjusted according to the excitation vibration frequency, and the cutoff vibration frequency can be adjusted. Therefore, the vibration of the first structure 20 can be effectively suppressed, and the amount of power generated by wave force can be effectively increased.

In the above-described embodiment, an example has been described in which the second pinion gear 103 meshes with the second rack rail 102 via the second speed change gear 105. However, this is not limited to the above. For example, the second speed change gear 105 does not have to be interposed between the second pinion gear 103 and the second rack rail 102. In this case, the second pinion gear 103 directly meshes with the second rack rail 102.

The above-described embodiment can suppress vibrations and increase the amount of electricity generated by wave power.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their variations are included within the scope and gist of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. Naturally, these embodiments can also be combined as appropriate within the gist of the invention.

In the above-described embodiment, a spar-type offshore wind power generation system has been described as an example. However, the present invention is not limited to this. For example, the present embodiment can also be applied to other floating offshore wind power generation systems, such as semi-submersible type, TetraSpar type, barge type, and tension leg platform (TLP) type. In this case, the first float 21 may be composed of multiple floats.

In the above-described embodiment, an example has been described in which the wave power generation device is applied to an offshore wind power generation system installed in seawater. However, this is not limited to this, and the wave power generation device may also be applied to an on-water wind power generation system installed in freshwater or brackish water. In this case, the first float 21 and the second float 31 float on the water.

1: Offshore wind power generation system, 2: Wind power generation equipment, 10: Wave power generation device, 20: First structure, 23: First rod, 25: First cavity, 30: Second structure, 32: Second cavity, 40: Intermediate structure, 46: First intermediate rod, 47: Second intermediate rod, 70: First conversion mechanism, 71: First conversion rotor, 72: First rack rail, 73: First pinion gear, 74: First speed change device, 80: First device generator, 81: First generator rotor, 100: Second conversion mechanism, 101: Second conversion rotor, 102: Second rack rail, 103: Second pinion gear, 104: Second speed change device, 110: Second device generator, 111: Second generator rotor, d: Axial direction, L2: Second central axis

Claims (15)

A first structure floating on the water; and
A second structure that floats on the water and is displaceable relative to the first structure;
an intermediate structure elastically connected to each of the first structure and the second structure and capable of being displaced relatively to each of the first structure and the second structure;
a first conversion mechanism including a first conversion rotor and configured to convert a relative displacement between the first structure and the intermediate structure into a rotational displacement of the first conversion rotor;
a first device generator including a first generator rotor, the first generator rotor being rotated by a rotational displacement of the first conversion rotor to generate electricity;
A wave power generation device, wherein the first generator rotor and the first converter rotor form a first rotating body that functions as an inertial mass element that reduces vibration transmission from the intermediate structure to the first structure. The wave power generation device according to claim 1, wherein the first device generator and the first conversion rotor are supported on the intermediate structure. The intermediate structure includes an intermediate cavity extending along a central axis,
The first structure includes a first rod extending along the central axis and inserted into the intermediate cavity;
The first conversion mechanism includes a first rack provided on the first rod and extending in an axial direction along the central axis,
the first converter rotor includes a first pinion gear coupled to the first generator rotor and meshing with the first rack;
The wave power generating device according to claim 2. The wave power generation device according to claim 1, wherein the first device generator and the first conversion rotor are supported by the first structure. The first structure includes a first cavity extending along a central axis,
The intermediate structure includes a first intermediate rod extending along the central axis and inserted into the first cavity,
the first conversion mechanism includes a first rack provided on the first intermediate rod and extending in an axial direction along the central axis,
5. The wave power generator of claim 4, wherein the first converter rotor includes a first pinion gear coupled to the first generator rotor and meshing with the first rack. The wave power generator according to claim 3 or 5, wherein the first conversion rotor includes a first speed gear interposed between the first rack and the first pinion gear. a second conversion mechanism including a second conversion rotor and configured to convert a relative displacement between the second structure and the intermediate structure into a rotational displacement of the second conversion rotor;
a second device generator including a second generator rotor, the second generator rotor being rotated by the rotational displacement of the second conversion rotor to generate power;
7. The wave power generation device according to claim 5, wherein the second generator rotor and the second converter rotor constitute a second rotor that functions as an inertial mass element that reduces vibration transmission from the intermediate structure to the second structure. The wave power generation device according to claim 7, wherein the second device generator and the second conversion rotor are supported by the second structure. the second structure includes a second cavity extending along the central axis;
The intermediate structure includes a second intermediate rod extending along the central axis and inserted into the second cavity,
the second conversion mechanism includes a second rack provided on the second intermediate rod and extending in an axial direction along the central axis,
9. The wave power generator according to claim 7 or 8, wherein the second converter rotor includes a second pinion gear coupled to the second generator rotor and meshing with the second rack. The wave power generator according to claim 9, wherein the second conversion rotor includes a second speed gear interposed between the second rack and the second pinion gear. A plurality of the second structures;
a plurality of intermediate structures elastically connected to the first structure and the corresponding second structure, the intermediate structures being relatively displaceable with respect to the first structure and the corresponding second structure;
a plurality of first conversion mechanisms for converting relative displacement between the first structure and the corresponding intermediate structure into rotational displacement of the first conversion rotor;
A wave power generation device according to any one of claims 1 to 10, comprising: a plurality of first device generators in which the first generator rotor rotates with a corresponding rotational displacement of the first conversion rotor to generate power. The wave power generation device according to claim 11, wherein, when viewed from above, the second structure and the intermediate structure are arranged in a circumferential direction around the first structure. The wave power generation device according to claim 11 or 12, wherein the second structures are connected to each other. The wave power generation device according to any one of claims 11 to 13, wherein the intermediate structures are connected to each other. A wave power generation device according to any one of claims 1 to 14,
and a wind power generation facility supported by the wave power generation device.