Device for reducing panning motion of floating windmill

Abstract

According to one embodiment of the present invention, a device for reducing the panning motion of a floating windmill is provided with: a floating body that floats on the water surface; the wind power generation device is arranged on the floating body; and a mooring cable for mooring the floating body, and the device is further provided with: a pan angle detection unit for detecting the displacement of the pan angle of the floating body in the pan direction with respect to a reference position; a pan angle suppression mechanism capable of applying a turning force in a pan direction to the floating body; and a pan angle control unit configured to control the pan angle suppression mechanism so as to apply, to the floating body, a turning force in a direction in which a long-period displacement among the displacements in the pan direction detected by the pan angle detection unit is reduced.

Description

Technical Field

[0001] The invention relates to a device for reducing the panning motion of a floating windmill.

[0002] This application claims priority based on Japanese Patent Application No. 2022-173892 filed with the Japan Patent Office on October 31, 2022, and the contents of which are incorporated herein by reference. Background Art

[0003] A floating windmill installed at sea comprises: a floating body that generates buoyancy so as to float on the water surface; a wind power generator installed on the floating body; and a mooring rope for mooring the floating body, etc. As an example of a floating body structure, the inventor first proposed a floating body comprising: a first column on which a wind power generator is installed; two second columns; and two hollow lower frames respectively connected between the first column part and the two second column parts, wherein the two lower frames have a structure connected by a beam member, and can suppress the resistance generated on the floating body relative to the force received from the tide or the current (Patent Document 1).

[0004] Previous technical literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2022 / 004690 Summary of the invention

[0007] Technical issues to be solved by the invention

[0008] In recent floating wind turbines, as the floating wind turbines have become larger in size, the long-period panning motion (rotational motion around a vertical line with the center of gravity of the floating body) occurring in the floating wind turbines tends to be too large. If the long-period panning motion occurs during power generation, the orientation of the rotor cannot be geometrically optimized with respect to the wind direction, so there are problems such as reduced power generation, increased load on the panning drive device or tower that adjusts the panning angle of the rotor, and increased maximum mooring force applied to the mooring rope that moors the floating wind turbine during storms. Therefore, there is a problem of shortening the fatigue life of the structure constituting the floating wind turbine.

[0009] In view of the above circumstances, an object of the present invention is to reduce the long-period displacement in the panning direction occurring in a floating windmill.

[0010] Means for solving technical problems

[0011] In order to achieve the above-mentioned purpose, the panning motion reducing device of the floating wind turbine involved in the present invention comprises: a floating body, floating on the water surface; a wind power generation device, arranged on the floating body; and a mooring rope, mooring the floating body, and the panning motion reducing device of the floating wind turbine also comprises: a panning angle detection unit, detecting the displacement of the panning angle of the floating body relative to the reference position in the panning direction; a panning angle suppression mechanism, capable of applying a rotational force in the panning direction to the floating body; and a panning angle control unit, configured to control the panning angle suppression mechanism to apply the rotational force to the floating body in the direction of reducing the long-period displacement in the displacement in the panning direction detected by the panning angle detection unit.

[0012] Effects of the Invention

[0013] According to one mode of the roll motion reducing device of the floating wind mill involved in the present invention, the long-period displacement in the roll direction occurring in the floating wind mill can be reduced, so that the angle of the rotor relative to the wind direction can be maintained at the optimum angle for power generation efficiency, thereby suppressing the reduction in power generation, suppressing the shortening of the fatigue life of the structures constituting the floating wind mill, and suppressing the increase in the maximum mooring force applied to the mooring rope during a storm. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a perspective view of a floating wind turbine equipped with a panning motion reducing device according to an embodiment.

[0015] Figure 2 It is a top view of a floating body provided with a roll angle suppression mechanism according to an embodiment.

[0016] Figure 3 This is a block diagram of a pan angle control unit according to an embodiment.

[0017] Figure 4 1 is a flowchart showing a control procedure of a pan angle control unit according to an embodiment.

[0018] Figure 5 This is a block diagram of a pan angle control unit according to an embodiment.

[0019] Figure 6 It is a top view of a floating body provided with a roll angle suppression mechanism according to an embodiment.

[0020] Fig. 7A It is a top view of a floating body provided with a roll angle suppression mechanism according to an embodiment.

[0021] Figure 7B It is magnified Fig. 7A A perspective view of a portion of the pan angle suppression mechanism shown in FIG.

[0022] Fig. 8A It is a top view of a floating body provided with a roll angle suppression mechanism according to an embodiment.

[0023] Figure 8B It is magnified Fig. 8A A perspective view of a portion of the pan angle suppression mechanism shown in FIG.

[0024] Fig. 9 It is a block diagram of a panning motion reducing device according to one embodiment.

[0025] Fig.10 This is a graph showing the analysis values ​​of displacement in the rolling direction occurring in the floating body in time series. DETAILED DESCRIPTION

[0026] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments or shown in the accompanying drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0027] For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" indicating relative or absolute configuration not only indicate such configuration in a strict sense, but also indicate a state of relative pan displacement at an angle or distance with a tolerance or a degree that can achieve the same function.

[0028] For example, expressions such as “same”, “equal” and “homogeneous” indicating that things are in the same state not only indicate the same state in a strict sense, but also indicate a state with a tolerance or a difference in degree to which the same function can be obtained.

[0029] For example, expressions indicating shapes such as a quadrilateral or a cylinder not only indicate shapes such as a quadrilateral or a cylinder in a strict geometric sense, but also indicate shapes including concavo-convex portions or chamfered portions as long as the same effect can be obtained.

[0030] On the other hand, the expression “having”, “including” or “having” a constituent element is not an exclusive expression that excludes the existence of other constituent elements.

[0031] (Structure of a floating windmill)

[0032] Figure 1 The floating wind turbine 1 includes: a floating body 10 having buoyancy and floating on the water surface Sw; a wind turbine 40 provided on the floating body 10 and supported on the water surface by the floating body 10; and a mooring rope 20 for mooring the floating body 10.

[0033] The wind power generator 40 includes a nacelle 42 disposed on the top of a tower 44; the tower 44 supports the nacelle 42 from below; and a rotor 46 rotatably mounted on the nacelle 42. The nacelle 42 is mounted on the tower 44 via a bearing so as to be rotatable in a panning direction, and the power generation efficiency can be improved by adjusting the orientation of the rotor 46 according to the wind direction. The rotor 46 has at least one blade 46a, and the blade 46a rotates against the wind W. The rotational energy of the rotor 46 is converted into electricity by a generator (not shown).

[0034] (Structure of floating body)

[0035] Figure 1 The floating body 10 shown in the figure has a first column 12, two second columns 14a, 14b, two lower frames 16a and 16b connecting the first column 12 and the second columns 14a, 14b, respectively, and a beam member 18 connected between the two lower frames 16a and 16b. The floating body 10 is generally A-shaped when viewed from above. The lower frames 16a, 16b and the beam member 18 extend along the water surface Sw. One end of each of a plurality of mooring ropes 20 is connected to the first column 12 and the second columns 14a, 14b, respectively, and the other end of each mooring rope 20 is connected to an anchor fixed to the seabed. The lower frames 16a and 16b have a hollow portion 22 formed therein, and are configured to be submersible by injecting ballast water into the hollow portion 22. Furthermore, in a state where ballast water is injected into the hollow portion 22, the lower frames 16a and 16b are completely submerged, and the upper surfaces thereof can be located below the waterline.

[0036] exist Figure 1 In the embodiment illustrated in the figure, the first column 12 and the second columns 14a and 14b form vertices of a virtual triangle in a top view. Furthermore, the axial lengths of the second columns 14a and 14b are almost the same, and the first column 12 is located at the top of the virtual isosceles triangle formed by the second columns 14a and 14b. The vertex angle formed by the second columns 14a and 14b is set within an angle range considering the stability of the floating body 10, for example, set to 90 degrees.

[0037] In another embodiment of the floating body 10, for example, the second columns 14a and 14b are composed of three columns instead of two columns, and the angles between the three second columns are configured to be equal in a plan view. Furthermore, the three second columns and the first column are respectively connected by three lower frames, and the first column is provided at the connection portion of the three lower frames.

[0038] (Panning motion reduction device)

[0039] like Figure 1As shown, a panning motion reduction device 50 according to one embodiment includes a panning angle detection unit 52 that detects the displacement of the panning angle of the floating body 10 in the panning direction relative to a reference position. The reference position here refers to a position in the panning direction set to a position where it is assumed that no displacement in the panning direction occurs. Fig.10 In the example, the reference position is the position in the panning direction set to 0 degrees.

[0040] The panning motion reducing device 50 further includes: a panning angle suppression mechanism 54 capable of applying a rotational force in the panning direction to the floating body 10; and a panning angle control unit 56 for controlling the panning angle suppression mechanism 54. The panning angle control unit 56 is configured to control the panning angle suppression mechanism 54 so as to apply a rotational force in a direction that reduces a long-period displacement among the displacements in the panning direction detected by the panning angle detection unit 52 to the floating body 10.

[0041] The pan angle control unit 56 is installed in, for example, an electrical room inside the tower 44, and includes a central processing unit (CPU) and memories such as ROM (Read Only Memory) and RAM (Random Access Memory). The CPU reads and executes information stored in the ROM, so that software and hardware cooperate to perform various processes. The RAM is used as a work area when the CPU executes a program.

[0042] Figure 2 It is a top view of a floating body provided with a roll angle suppression mechanism according to an embodiment.

[0043] exist Figure 2 In FIG. 1 , point G is the center of gravity (buoyancy) of the floating body 10. The position of the center of gravity G of the floating body 10 varies depending on the structure of the floating body. As shown by arrow T, the rotational force in the panning direction is a rotational force that causes the floating body 10 to rotate in either the positive or negative (+ / -) direction in the panning direction around the center of gravity G.

[0044] Fig.10 This is a graph showing the analysis value of the displacement in the rolling direction occurring in the floating body in a time series. Specifically, this is a graph showing the calculation results of the displacement in the rolling direction of the floating body by systematically changing the viscous damping force (ψ) applied to the floating body in the rolling direction to 0%, 20%, and 40%. The horizontal axis represents time (seconds) and the vertical axis represents the displacement angle in the rolling direction.

[0045] Fig.10The displacement in the panning direction shown is represented by a waveform pattern including a long-period component of a waveform with a period x of about 60 seconds and a short-period component of a waveform with a period y of about 10 seconds. It is the long-period component that causes a decrease in the power generation of the floating wind turbine or a shortening of the fatigue life and an increase in the maximum mooring force. Generally, the fatigue life is inversely proportional to the cube of the amplitude of the variable load applied to the structure, so if the amplitude of the variable load is reduced by about 20%, the fatigue life is extended by about 2 times, and if the amplitude of the variable load is reduced by about 30%, the fatigue life is extended by about 3 times.

[0046] The long-period displacement in the pan direction detected by the pan angle detection unit 52 refers to Fig.10 The displacement corresponding to the wave period component longer than a predetermined period in the waveform pattern shown.

[0047] According to the panning motion reduction device 50, the panning angle control unit 56 can control the operation of the panning angle suppression mechanism 54 to apply a rotation force T in a direction that reduces a long-period displacement corresponding to a wave period component of a predetermined period or longer, among displacements in the panning direction of the floating body 10 detected by the panning angle detection unit 52. As a result, the rotor 46 can maintain an optimal angle in terms of power generation efficiency with respect to the wind direction, thereby suppressing a reduction in the amount of power generated by the floating wind turbine 1, suppressing a reduction in the fatigue life of the structure constituting the floating wind turbine 1, and suppressing an increase in the maximum mooring force applied to the mooring rope 20 during a storm or the like.

[0048] (One embodiment of a pan angle detection unit)

[0049] Figure 1 The pan angle detection unit 52 illustrated in the figure includes an azimuth sensor 58 provided at the top of the first column 12 and a processing unit 62. The processing unit 62 is, for example, built into the azimuth sensor 58. The azimuth sensor 58 has a plurality of antennas built therein, and each of these plurality of antennas captures a carrier wave transmitted from a GPS satellite 60. The processing unit 62 is configured to obtain the displacement of the floating body 10 in the pan angle direction based on the path difference of the carrier wave between the antennas and the baseline vector set to connect the positions of the antennas. The data such as the displacement of the floating body 10 in the pan angle direction obtained by the processing unit 62 is output to an external device via a display (not shown).

[0050] Figure 3 FIG. 5 is a block diagram of a pan angle control unit 56 according to an embodiment. The displacement in the pan direction detected by the pan angle detection unit 52 is as follows: Fig.10 When the time series changes are expressed in this way, it becomes a waveform pattern including a short-period wave component and a long-period wave component with a period longer than a predetermined period.

[0051] Figure 3The panning angle control unit 56 shown in the figure comprises: a filtering unit 66 configured to extract a long-period wave component Ld having a predetermined period or longer from the wave period components included in the waveform pattern; and a long-period displacement calculation unit 68 configured to calculate a long-period displacement Ld corresponding to the long-period wave component Ld extracted by the filtering unit 66. 0 .

[0052] The displacement Dj in the panning direction detected by the panning angle detection unit 52 is extracted in advance by the filter unit 66 for a long-period wave component Ld having a predetermined period or longer, before being input to the long-period displacement calculation unit 68. The long-period displacement calculation unit 68 calculates the long-period displacement Ld corresponding to the long-period wave component Ld extracted by the filter unit 66. 0 According to the long-period displacement Ld calculated by the long-period displacement calculation unit 68 0 The rotation force to be applied to the floating body 10 to reduce the long-period displacement occurring in the floating body 10 is set. By providing the filter unit 66 and the long-period displacement calculation unit 68, the rotation force for reducing the long-period displacement occurring in the floating body 10 can be accurately set.

[0053] In the filter unit 66, for example, a wave period component with a period of 30 seconds or more is extracted as the long-period wave component Ld. However, when it is desired to accurately extract the long-period wave component Ld, a wave period component with a period of 45 to 75 seconds is extracted. In addition, when it is desired to exclude the short-period wave component as much as possible and extract the long-period wave component Ld more accurately, a wave period component with a period of 55 to 65 seconds is extracted.

[0054] In one embodiment, the filter unit 66 performs a process using a fast Fourier transform on the displacement Dj in the panning direction detected by the panning angle detection unit 52. By this process, the displacement Dj in the panning direction detected by the panning angle detection unit 52 is clearly distinguished between the long-period wave component and the short-period wave component, and thus it is easy to extract the long-period wave component Ld from the displacement Dj in the panning direction.

[0055] In one embodiment, if Figure 3 As shown, the pan angle control unit 56 is configured to perform feedback control in which the pan angle suppression mechanism 54 is operated so that the long-period displacement Ld extracted from the displacement Dj in the pan direction detected by the pan angle detection unit 52 is reduced. 0 The pan angle control unit 56 performs feedback control so that the long-period displacement Ld extracted from the displacement Dj in the pan direction detected by the pan angle detection unit 52 is reduced to the target displacement Dt. 0 Close to the target displacement Dt, the long-period displacement Ld generated in the floating body 10 can be reduced. 0 Rapidly converge to the target displacement Dt.

[0056] exist Figure 3In the embodiment illustrated in FIG. 1 , the long-period displacement Ld calculated by the long-period displacement calculation unit 68 is 0 The target displacement Dt and the long-period displacement Ld are output to the comparator 64. 0 The pan angle control unit 56 controls the operation of the pan angle suppression mechanism 54 so that the difference Δ approaches zero.

[0057] Figure 4 Yes means Figure 3 Flowchart of the control steps of the pan angle control unit 56 is shown.

[0058] exist Figure 4 In the above process, if the pan angle detection unit 52 detects the displacement Dj in the pan direction occurring in the floating body 10 (step S10), the filter unit 66 performs filtering to extract the long-period wave component Ld from the displacement Dj in the pan direction (step S12). Next, the long-period displacement calculation unit 68 calculates the long-period displacement Ld corresponding to the long-period wave component Ld as the long-period displacement to be compared with the target displacement Dt in step S16 described later. 0 (Step S14). The calculated long-period displacement Ld 0 The target displacement Dt and the long-period displacement Ld are then output from the comparator 64. 0 The roll angle control unit 56 controls the operation of the roll angle suppression mechanism 54 so that the roll angle suppression mechanism 54 applies a rotational force T to the floating body 10 that reduces the long-period displacement occurring in the floating body 10 so that the difference Δ becomes zero.

[0059] As an example of a control method using the pan angle control unit 56, for example, if Fig.10 When the target displacement Dt is set to ±3 degrees, the long-period displacement Ld calculated by the long-period displacement calculation unit 68 is 0 When the pan angle control unit 56 controls the pan angle suppression mechanism 54 so that the long-period displacement Ld 0 Close to +3 degrees. When the long-period displacement Ld calculated by the long-period displacement calculation unit 68 is 0 When the pan angle control unit 56 controls the pan angle suppression mechanism 54 so that the long-period displacement Ld 0 Close to -3 degrees.

[0060] according to Figure 3 and Figure 4In the embodiment illustrated in FIG. 1 , the pan angle control unit 56 extracts the long-period wave component Ld from the displacement Dj in the pan direction detected by the pan angle detection unit 52 in the filter unit 66, and further performs feedback control so that the long-period displacement Ld calculated by the long-period displacement calculation unit 68 in correspondence with the long-period wave component Ld is 0 Since the target displacement Dt is approached, control can be quickly performed to make the long-period displacement in the rolling direction generated in the floating body 10 approach the target displacement Dt.

[0061] Figure 5 It is a block diagram of the pan angle control unit 56 according to another embodiment, and more specifically, it is an embodiment in which the pan angle control unit 56 performs PID control as feedback control.

[0062] exist Figure 5 In P control (proportional control), the target displacement Dt is proportional to the long-period displacement Ld. 0 The result obtained by multiplying the difference Δ by the proportional gain Kp is output to the adder 70. In I control (integral control), the difference Δ is integrated over time, and the output value obtained by processing the difference Δ with the integral gain Ki is output to the adder 70 to fill the target displacement Dt and the long-period displacement Ld that cannot be filled in P control. 0 In D control (differential control), the output value of the negative component obtained by processing the differential gain Kd on the difference Δ is output to the adder 70 to avoid over-adjustment. Through these processes, the panning angle control unit 56 can make the long-period displacement occurring in the floating body 10 quickly and stably approach the target displacement Dt.

[0063] (Panning Angle Suppression Mechanism According to First Embodiment)

[0064] exist Figure 2 In the embodiment shown in the figure, six mooring ropes 20 (20a to 20f) are provided to exert a mooring force Fm in different directions with respect to the floating body 10. The mooring ropes 20a, 20c, and 20f can respectively exert a mooring force Fm on the floating body 10 to resist a negative (-) direction rotation force T centered on the center of gravity G of the floating body 10, and the mooring ropes 20b, 20d, and 20e can respectively exert a mooring force Fm on the floating body 10 to resist a positive (+) direction rotation force T opposite to the negative direction centered on the center of gravity G of the floating body 10.

[0065] The roll angle suppression mechanism 54a according to one embodiment includes a hydraulic cylinder 72a (second hydraulic cylinder) provided at a connection portion between the mooring rope 20a (second mooring rope) and the floating body 10, and a hydraulic cylinder 72b (first hydraulic cylinder) provided at a connection portion between the mooring rope 20b (first mooring rope) and the floating body 10. The hydraulic cylinders 72a and 72b are respectively arranged at the connection portion so that the pistons can slide in the direction in which the mooring force Fm is applied to the floating body 10. That is, the hydraulic cylinders 72a and 72b are respectively arranged so as to be able to extend and retract in the direction in which the mooring force Fm is applied. The roll angle suppression mechanism 54a includes a hydraulic oil supply and discharge portion 74 for supplying and discharging hydraulic oil to and from two oil chambers of the hydraulic cylinders 72a and 72b. The roll angle control portion 56 is configured to control the timing of supplying and discharging hydraulic oil to and from the two oil chambers of the hydraulic cylinders 72a and 72b by the hydraulic oil supply and discharge portion 74 in accordance with the displacement in the roll direction occurring in the floating body 10.

[0066] In addition, the hydraulic cylinders 72a and 72b may be arranged at the connection between the floating body 10 and the mooring line 20a or 20b so as to be accommodated inside the part of the floating body 10 located underwater or above the water. In another embodiment, the hydraulic cylinders 72a and 72b may also be provided at a predetermined position in the length direction of the mooring line 20 instead of the connection between the floating body 10 and the mooring line 20.

[0067] Furthermore, the hydraulic oil supply and discharge portion 74 may be provided inside the second columns 14 a and 14 b .

[0068] In the present embodiment, the displacement in the pan direction of the floating body 10 can be reduced by controlling the operation of the hydraulic cylinders 72a and 72b by the pan angle control unit 56 in accordance with the displacement in the pan direction of the floating body 10. For example, when the displacement in the positive pan direction occurs in the floating body 10, the hydraulic cylinder 72b is extended in accordance with the time when the displacement occurs, and the displacement in the positive pan direction can be suppressed while suppressing the increase of the mooring force Fm applied to the mooring line 20b. On the contrary, when the displacement in the negative pan direction occurs in the floating body 10, the hydraulic cylinder 72a is extended in accordance with the time when the displacement occurs, and the displacement in the negative pan direction can be suppressed while suppressing the increase of the mooring force Fm applied to the mooring line 20a.

[0069] As described above, according to the present embodiment, with a simple structure including only the hydraulic cylinders 72 a and 72 b , a turning force capable of reducing displacement in both the positive and negative rolling directions can be applied to the floating body 10 .

[0070] In addition, Figure 2In the embodiment, hydraulic cylinders may be provided in the mooring ropes 20c and 20d or the mooring ropes 20e and 20f instead of the mooring ropes 20a and 20b. However, in the case of the hydraulic cylinders 72a and 72b, the magnitude of the turning force T applied to the floating body 10 is determined by the straight line L along the direction of the mooring force Fm applied to the floating body 10 from the mooring rope 20a via the hydraulic cylinder 72a or from the mooring rope 20b via the hydraulic cylinder 72b on the center line O passing through the center of gravity G in a top view. 1 The distance D from the center of gravity G is determined by the product of the mooring force Fm. Therefore, it is preferable to provide a hydraulic cylinder on the mooring ropes 20a and 20b that can increase the value of the distance D.

[0071] Furthermore, in another embodiment, hydraulic cylinders may be provided on all mooring ropes 20a to 20f, thereby maximizing the rotational force applied to the floating body 10 in both positive and negative directions, and generating a rotational force T that can accurately reduce the displacement in the panning direction of the floating body 10 by independently adjusting the operation of each hydraulic cylinder.

[0072] (Panning Angle Suppression Mechanism According to Second Embodiment)

[0073] Figure 6 FIG. 1 is a top view of another embodiment of a floating body 10 having a pan angle suppression mechanism 54. Figure 6 and the following Fig. 7A and Fig. 8A In the figure, the mooring rope 20 is omitted.

[0074] In this embodiment, the roll angle suppression mechanism 54b includes at least one water jet propeller 76, the water jet port of which is provided on the floating body 10 above the water surface, and can spray water in a direction that reduces the long-period displacement occurring in the floating body 10. The roll angle control unit 56 controls the spray amount and spray direction of the water jetted from the water jet port of the water jet propeller 76 in accordance with the timing of the long-period displacement occurring in the roll direction in the floating body 10.

[0075] According to the present embodiment, the roll angle suppression mechanism 54b realizes a simple structure having only at least one water jet propeller 76. That is, by setting the direction of the water jet port of one water jet propeller 76 to be variable in both positive and negative directions, a rotation force capable of reducing displacement in both positive and negative roll directions can be applied to the floating body 10 by one water jet propeller 76.

[0076] exist Figure 6In the embodiment illustrated in the figure, a water jet propeller 76a is provided at the front end of the lower frame 16a in such a manner that the water jet outlet is located higher than the water surface, and a water jet propeller 76b is provided at the front end of the lower frame 16b in such a manner that the water jet outlet is located higher than the water surface. In the figure, arrow a and arrow b indicate the spray direction of the water flow sprayed from the water jet outlet of the water jet propeller 76a or 76b. The spray direction a of the water flow sprayed from the water jet outlet of the water jet propeller 76a and the spray direction b of the water flow sprayed from the water jet outlet of the water jet propeller 76b are configured to be positive and negative directions to each other when viewed from above. Since there are two water jet propellers 76a and 76b whose spray directions of the water flow are positive and negative directions to each other, it is possible to add a rotational force that can reduce the displacement in the positive and negative directions of the panning direction occurring in the floating body 10.

[0077] In addition, Figure 6 In the embodiment, the water jet direction of the water jet port of the water jet propulsion device 76a or 76b is set to be parallel to the straight line L connecting the center of gravity G and the position where the water jet propulsion device 76a or 76b is installed. 2 The orthogonal direction can increase the turning force.

[0078] exist Figure 6 In the embodiment illustrated in FIG. 1 , a pair of water jets 76 a and 76 b are provided. However, in another embodiment, a single water jet capable of changing the direction of the water jet port to include directions a and b may be provided.

[0079] (Panning Angle Suppression Mechanism According to Third Embodiment)

[0080] Fig. 7A It is a top view of a floating structure 10 according to still another embodiment that includes a roll angle suppression mechanism 54 . Figure 7B It is magnified Fig. 7A The perspective view of a part of the roll angle suppression mechanism shown in FIG. 1 is a perspective view of the vicinity of the second column 14 b of the floating body 10 .

[0081] The roll angle suppression mechanism 54c according to this embodiment includes: at least one blade 78, which is provided on the floating body 10 above the water surface Sw and has a wing-shaped cross section; a rotation shaft 80, which is arranged in the vertical direction and rotatably supports the blade 78; and a blade driving unit 82, which rotates the blade 78 around the rotation shaft 80. Since the blade 78 has a cross section (a cross section in a direction perpendicular to the rotation shaft 80) in the shape of a wing, when the blade 78 is blown by the wind W, a lift C is generated in the back direction perpendicular to the chord (a line segment connecting the leading edge and the trailing edge of the blade 78). The roll angle control unit 56 is configured to control the operation of the blade driving unit 82 to adjust the direction of the blade 78 so as to generate the lift C in the direction of reducing the long-period displacement in the roll direction generated in the floating body 10. In this way, by controlling the operation of the blade driving unit 82 by the roll angle control unit 56, a rotation force T that reduces the long-period displacement in the roll direction generated in the floating body 10 can be applied to the floating body 10.

[0082] According to the present embodiment, the roll angle suppression mechanism 54c realizes a simple structure including only at least one blade 78 and a blade driving unit 82 capable of adjusting the direction of the blade 78. In addition, the direction of the lift C generated by the blade 78 can be changed simply by changing the direction of the blade 78 in accordance with the direction of the wind W. Therefore, the rotation force T capable of reducing the long-period displacement in both the positive and negative directions in the roll direction generated in the floating body 10 can be added to the floating body 10 by one blade 78.

[0083] exist Fig. 7A In the embodiment illustrated in FIG. 1 , the blade 78a is provided on the top surface of the second column 14a, and the blade 78b is provided on the top surface of the second column 14b. As a result, the distance D defined as described above can be made larger, so that the rotation force applied to the floating body 10 in the panning direction can be increased. Furthermore, if the orientations of the blades 78a and 78b can be changed independently, the long-period displacement occurring in the floating body 10 can be further effectively reduced.

[0084] And, in Fig. 7A In the embodiment illustrated in the figure, two blades 78a and 78b are provided. However, if a single blade can be rotated to any angle of 360 degrees by the blade driving unit 82, a lift C capable of applying a rotation force T in both positive and negative directions to the floating body 10 can be generated by a single blade.

[0085] (Panning Angle Suppression Mechanism According to Fourth Embodiment)

[0086] Fig. 8A It is a top view of a floating structure 10 according to still another embodiment that includes a roll angle suppression mechanism 54 . Figure 8B It is magnified Fig. 8AThe perspective view of a part of the roll angle suppression mechanism shown in FIG. 1 is a perspective view of the vicinity of the second column 14 b of the floating body 10 .

[0087] The pan angle suppression mechanism 54d involved in this embodiment includes: at least one rotor sail 84, which is erected on the floating body 10 higher than the water surface Sw; a rotating shaft 86, which is arranged in the center of the rotor sail 84 along the vertical direction and supports the rotor sail 84 in a rotatable manner; and a rotor sail driving unit 88, which rotates the rotor sail 84 around the rotating shaft 86.

[0088] The roll angle suppression mechanism 54d utilizes the Magnus effect, and the rotor sail 84 placed in the wind W rotates around the rotation axis 86, so that areas with different wind speeds are generated on both sides of the cross section of the rotor sail 84. Compared with the area with a low wind speed, the area with a high wind speed becomes low pressure, so lift C is generated from the high pressure area to the low pressure area. The lift C increases as the rotation speed of the rotor sail 84 increases. The roll angle control unit 56 is configured to control the direction and size of the generated lift C by controlling the rotation direction and rotation speed of the rotor sail 84, and to generate a rotational force T that reduces the long-period displacement generated in the floating body 10 using the lift C. Therefore, by controlling the rotation direction and rotation speed of the rotor sail 84 by the roll angle control unit 56d, it is possible to generate lift C in the direction of reducing the long-period displacement of the floating body 10.

[0089] According to the present embodiment, the roll angle suppression mechanism 54 d has a simple structure including only one rotor sail 84 , and can apply a rotation force capable of reducing long-period displacement in both positive and negative directions in the roll direction occurring in the floating body 10 .

[0090] Figure 8B The rotor sail 84b shown in the example is composed of a columnar body with a circular cross section. Therefore, the resistance to the wind W blowing on the columnar body can be suppressed to be small, so the pressure difference between the two side areas of the columnar body can be increased. As a result, the generated lift C can be increased.

[0091] In addition, the cross-section of the rotor sail 84 may be a shape other than a circle, for example, an ellipse.

[0092] exist Fig. 8A In the embodiment illustrated in FIG. 1 , the rotor sail 84a is disposed on the top surface of the second column 14a, and the rotor sail 84b is disposed on the top surface of the second column 14b. Thus, the distance D defined as described above can be made larger, thereby increasing the turning force applied to the floating body 10 in the rolling direction.

[0093] (Panning Angle Suppression Mechanism According to Fifth Embodiment)

[0094] Fig. 92 is a block diagram showing another embodiment of the panning motion reducing device 50 .

[0095] like Figure 1 As shown, the wind turbine generator 40 includes at least one blade 46a whose inclination angle Ap can be changed. Fig. 9 As shown, the panning angle suppression mechanism 54 e according to the present embodiment includes a tilt drive unit 94 for making the tilt angle Ap of the blade 46 a variable inside the rotor 46 . The tilt drive unit 94 includes an actuator such as a motor or a hydraulic cylinder.

[0096] The pan angle control unit 56 includes a tilt adjustment unit 92 that can control the operation of the tilt drive unit 94 to adjust the tilt angle Ap of the blade 46a. That is, when displacement in the pan direction occurs in the floating body 10, the tilt adjustment unit 92 controls the operation of the tilt drive unit 94 to adjust the tilt angle Ap of the blade 46a so that the blade 46a blown by the wind W can apply a rotation force T in a direction that reduces the long-period displacement in the displacement in the pan direction to the floating body 10. By performing such control by the pan angle control unit 56, the rotation force T that reduces the long-period displacement occurring in the floating body 10 can be applied.

[0097] This embodiment can be executed even when the inclination angle Ap of the blade 46a is at the inclination angle Ap at which power generation is possible or when the blade 46a is at the blade angle at which power generation is stopped while the wind turbine generator 40 is performing power generation operation.

[0098] According to the present embodiment, the rotation force T in the direction of reducing the long-period displacement occurring in the floating body 10 can be applied to the floating body 10 only by adjusting the inclination angle Ap of the blade 46a by the inclination adjusting unit 92, so there is no need to provide a new device requiring power as the roll angle suppression mechanism 54e. Therefore, the cost of the roll angle suppression mechanism 54e can be reduced.

[0099] When the rotor 46 includes a plurality of blades 46 a , by configuring the rotation direction and rotation speed of each blade 46 a to be independently controllable, a sufficient rotation force T in a direction to reduce the long-period displacement occurring in the floating body 10 can be accurately generated.

[0100] exist Fig. 9 In the embodiment illustrated in FIG. 1 , the pan angle control unit 56 stores a correlation diagram 90 obtained based on past actual measurement data of the floating wind turbine 1 for the correlation between the detection value of the long-period component detected by the pan angle detection unit 52 and the slewing force T that can reduce the generated long-period component. When the detection value of the displacement in the pan direction occurring in the floating body 10 is input from the pan angle detection unit 52 to the pan angle control unit 56, the tilt adjustment unit 92 controls the tilt drive unit 94 based on the correlation diagram 90. As a result, the long-period displacement occurring in the floating body 10 can be automatically and accurately reduced.

[0101] The contents described in the above-mentioned embodiments can be understood, for example, as follows.

[0102] 1) A method for reducing the rolling motion of a floating wind turbine 50 includes: a floating body 10 floating on a water surface Sw; a wind turbine 40 arranged on the floating body 10; and a mooring rope 20 mooring the floating body 10, and the floating wind turbine rolling motion reducing device also includes: a rolling angle detection unit 52 for detecting a displacement Dj of the rolling angle of the floating body 10 in the rolling direction relative to a reference position; a rolling angle suppression mechanism 54 capable of applying a rotational force T in the rolling direction to the floating body 10; and a rolling angle control unit 56 configured to control the rolling angle suppression mechanism 54 so as to apply the rotational force T in the direction of reducing the long-period displacement in the displacement Dj in the rolling direction detected by the rolling angle detection unit 52 to the floating body 10.

[0103] According to the above configuration, the pan angle control unit 56 controls the operation of the pan angle suppression mechanism 54 so as to apply a rotation force T in a direction that reduces the long-period displacement in the pan direction of the floating body 10 detected by the pan angle detection unit 52 to the floating body 10, thereby reducing the long-period displacement in the pan direction applied to the floating body 10. As a result, the orientation of the rotor 46 can be maintained at an angle that is optimal for power generation efficiency with respect to the wind direction, thereby suppressing a reduction in power generation, suppressing a reduction in fatigue life of the structure constituting the floating wind turbine 1, and suppressing an increase in the maximum mooring force applied to the mooring rope 20 during a storm or the like.

[0104] 2) In another embodiment of the floating wind turbine panning motion reduction device 50, in the floating wind turbine panning motion reduction device described in 1), the panning angle control unit 56 includes: a filter unit 66 configured to extract a long-period wave component Ld having a predetermined period or longer from a waveform pattern representing a time series change of the displacement Dj in the panning direction detected by the panning angle detection unit 52; and a long-period displacement calculation unit 68, which calculates the long-period displacement Ld corresponding to the long-period wave component Ld extracted by the filter unit 66. 0 .

[0105] Before the displacement Dj in the panning direction detected by the panning angle detection unit 52 is input to the long-period displacement calculation unit 68, the long-period wave component Ldj having a predetermined period or longer is extracted in advance by the filtering unit 66. 0 , and input to the long-period displacement calculation unit 68. In the long-period displacement calculation unit 68, the long-period displacement Ld is calculated corresponding to the long-period wave component Ld extracted by the filter unit 66. 0 According to the long-period displacement Ld calculated in this way 0The rotation force T to be applied to the floating body 10 to reduce the long-period displacement occurring in the floating body 10 is set. According to the above configuration, since the filter unit 66 and the long-period displacement calculation unit 68 are provided, the rotation force T for reducing the long-period displacement occurring in the floating body 10 can be accurately set.

[0106] 3) In another embodiment of the floating wind turbine roll motion reduction device, in the floating wind turbine roll motion reduction device described in 1) or 2), the roll angle control unit 56 is configured to perform feedback control, and in the feedback control, the roll angle suppression mechanism 54 is operated to make the long-period displacement close to the target displacement Dt.

[0107] According to this configuration, the pan angle control unit 56 performs feedback control so that the long-period displacement included in the displacement Dj in the pan direction detected by the pan angle detection unit 52 approaches the target displacement Dt, thereby making it possible to reduce the long-period displacement Ld generated in the floating body 10 to 0 Rapidly converge to the target displacement Dt.

[0108] 4) In another embodiment of the floating wind turbine roll motion reducing device 50, in the floating wind turbine roll motion reducing device described in any one of 1) to 3), the mooring rope 20 includes: a first mooring rope 20b, which can add a mooring force Fm to the floating body 10 to resist the displacement Dj in the positive roll direction; and a second mooring rope 20a, which can add a mooring force Fm to the floating body 10 to resist the displacement Dj in the negative roll direction opposite to the positive direction, and the roll angle suppression mechanism 54a includes: a first hydraulic cylinder 72b, which is arranged at the first mooring rope 20b or at the connection portion between the first mooring rope 20b and the floating body 10; and a second hydraulic cylinder 72a, which is arranged at the second mooring rope 20a or at the connection portion between the second mooring rope 20a and the floating body 10.

[0109] According to this structure, the panning angle suppression mechanism 54a has a simple structure including only the first hydraulic cylinder 72b and the second hydraulic cylinder 72a. By operating these hydraulic cylinders, a rotation force T capable of reducing the panning displacement in both positive and negative directions occurring in the floating structure 10 can be applied.

[0110] 5) In another embodiment of the rolling motion reducing device 50 of a floating windmill, in the rolling motion reducing device of a floating windmill described in any one of 1) to 3), the rolling angle suppression mechanism 54b includes at least one water jet propeller 76, the water jet port of the water jet propeller 76 is arranged on the floating body 10 above the water surface Sw, and can spray water in the direction of reducing the long-period displacement.

[0111] According to this structure, the roll angle suppression mechanism 54b realizes a simple structure having only at least one water jet 76. That is, by making the direction of the water jet port of one water jet 76 variable in both positive and negative directions, the one water jet 76 can add a rotation force T to the floating body 10 that can reduce the roll direction displacement in both positive and negative directions.

[0112] 6) In another embodiment of the floating windmill roll motion reducing device 50, in the floating windmill roll motion reducing device described in any one of 1) to 3), the roll angle suppression mechanism 54c includes: at least one blade 78, which is arranged on the floating body 10 above the water surface Sw and has a wing-shaped cross-section; and a blade driving unit 82, which rotates the blade 78 around the center of the axis.

[0113] When the wind W passes through the blade 78 having the wing-shaped cross section, a pressure difference is generated between the back side and the ventral side of the blade 78 , thereby generating a lift C that is orthogonal to the chord of the blade 78 and is directed toward the back side of the low pressure.

[0114] According to the above configuration, the roll angle suppression mechanism 54c has a simple configuration including only at least one blade 78. That is, the direction of the lift force C generated by the blade 78 can be changed by simply changing the direction of one blade 78 by the blade driving unit 82. Thus, a rotation force T capable of reducing long-period displacement in both positive and negative directions in the roll direction generated in the floating body 10 can be added.

[0115] 7) In another embodiment of the rolling motion reducing device 50 for a floating windmill, in the rolling motion reducing device for a floating windmill described in any one of 1) to 3), the rolling angle suppression mechanism 54d includes: at least one rotor sail 84, which is erected on the floating body 10 above the water surface Sw in a manner that allows it to rotate around an axis center; and a rotor sail driving unit 88, which causes the rotor sail 84 to rotate around the axis center.

[0116] Rotating the rotor sail 84 about the axis center generates a pressure difference between one side region and the other side region of the rotor sail 84 in the cross section of the rotor sail 84 , thereby generating a lift C toward the low pressure side of the rotor sail 84 .

[0117] According to the above configuration, the roll angle suppression mechanism 54d realizes a simple configuration including only at least one rotor sail 84. That is, the direction of the lift C generated on the rotor sail 84 can be changed simply by changing the rotation speed and the rotation direction of one rotor sail 84 by the rotor sail driving unit 88. Thus, a rotation force capable of reducing long-period displacement in both positive and negative directions in the roll direction generated in the floating body 10 can be added.

[0118] 8) In another embodiment of the floating windmill roll motion reducing device 50, in the floating windmill roll motion reducing device described in any one of 1) to 3), the wind power generation device 40 includes at least one blade 46a capable of changing the inclination angle Ap, the roll angle suppression mechanism 54e includes a blade driving unit 94 capable of changing the inclination angle Ap of the blade 46a, and the roll angle control unit 56 includes a inclination adjustment unit 92, and the inclination adjustment unit 92 adjusts the inclination angle Ap of the blade 46a so that the blade 46a blown by the wind W can apply the rotational force T to the floating body 10.

[0119] According to this structure, by simply adjusting the inclination angle Ap of the blade 46a by the inclination adjusting portion 92, a rotation force T in a direction of reducing the long-period displacement occurring in the floating body 10 can be applied to the floating body 10. Therefore, there is no need to provide a new device requiring power as the panning motion reducing device 50, and the cost of the panning motion reducing device 50 can be reduced.

[0120] Explanation of symbols

[0121] 1- floating windmill, 10- floating body, 12- first column, 14a, 14b- second column, 16a, 16b- lower frame, 18- beam member, 20 (20a, 20b, 20c, 20d, 20e, 20f)- mooring rope, 20a- mooring rope (first mooring rope), 20b- mooring rope (second mooring rope), 22- hollow part, 40- wind turbine generator, 42- nacelle, 44- tower, 46- rotor, 46a- blade, 50- panning motion reduction device, 52- panning angle detection unit, 54 (54a, 54b, 54c, 54d, 54e)- panning angle suppression mechanism, 56- panning angle control unit, 58- azimuth sensor, 60- GPS satellite, 62- processing unit, 64- comparator, 66- filter unit, 68- long period displacement calculation , 70-adder, 72a-hydraulic cylinder (second hydraulic cylinder), 72b-hydraulic cylinder (first hydraulic cylinder), 74-working oil supply and discharge part, 76 (76a, 76b)-water jet propulsion, 78 (78a, 78b)-blade, 80-rotation axis, 82-blade driving part, 84 (84a, 84b)-rotor sail, 86-rotation axis, 88-rotor sail driving part, 90-correlation diagram, 92-tilt adjustment part, 94-tilt driving part, Ap-tilt angle, C-lift, D-distance, Dj-displacement in the panning direction, Dt-target displacement, Fm-mooring force, Kd-proportional gain, Ki-integral gain, Kp-differential gain, L1, L2-straight line, Ld-long period wave component, Ld0-long period displacement, Sw-water surface, T-rotational force, W-wind.

Claims

1. A device for reducing the panning motion of a floating windmill, comprising: a floating body floating on the water surface; a wind power generation device arranged on the floating body; and a mooring rope mooring the floating body, the device for reducing the panning motion of a floating windmill further comprising: A pan angle detection unit, which detects the displacement of the pan angle of the floating body relative to a reference position in the pan direction; a panning angle suppression mechanism capable of applying a rotational force in a panning direction to the floating body; and The pan angle control unit is configured to control the pan angle suppression mechanism so as to apply the rotation force in a direction that reduces a long-period displacement among the displacements in the pan direction detected by the pan angle detection unit to the floating body.

2. The device for reducing the panning motion of a floating windmill according to claim 1, wherein: The pan angle control unit comprises: a filtering unit configured to extract a long-period wave component having a predetermined period or longer from a waveform pattern represented by a time-series change of the displacement in the panning direction detected by the panning angle detection unit; and The long-period displacement calculation unit calculates the long-period displacement corresponding to the long-period wave component extracted by the filtering unit.

3. The device for reducing the panning motion of a floating windmill according to claim 1, wherein: The pan angle control unit is configured to perform feedback control in which the pan angle suppression mechanism is operated so that the long-period displacement approaches a target displacement.

4. The device for reducing the panning motion of a floating windmill according to any one of claims 1 to 3, wherein: The mooring rope comprises: a first mooring rope capable of adding a mooring force to the floating body to resist displacement in the positive rolling direction; and The second mooring rope is capable of adding a mooring force to the floating body to resist displacement in the negative rolling direction opposite to the positive direction. The pan angle suppression mechanism comprises: a first hydraulic cylinder, provided at the first mooring rope or at a connection portion between the first mooring rope and the floating body; and The second hydraulic cylinder is provided at the second mooring rope or at a connection portion between the second mooring rope and the floating body.

5. The device for reducing the panning motion of a floating windmill according to any one of claims 1 to 3, wherein: The panning motion suppression mechanism includes at least one water jet propulsion device, the water jet port of the water jet propulsion device is arranged on the floating body above the water surface, and can spray water in the direction of reducing the long-period displacement.

6. The device for reducing the panning motion of a floating windmill according to any one of claims 1 to 3, wherein: The panning motion suppression mechanism comprises: at least one blade disposed on the floating body above the water surface and having a wing-shaped cross-section; and The blade driving part makes the blade rotate around the axis center.

7. The device for reducing the panning motion of a floating windmill according to any one of claims 1 to 3, wherein: The pan angle suppression mechanism comprises: at least one rotor sail erected on the floating body above the water surface in a manner rotatable about an axis center; and The rotor sail driving unit causes the rotor sail to rotate around an axis center.

8. The device for reducing the panning motion of a floating windmill according to any one of claims 1 to 3, wherein: The wind power generation device comprises at least one blade whose tilt angle can be changed. The panning angle suppression mechanism includes a blade driving unit capable of changing the inclination angle of the blade. The pan angle control unit includes a tilt adjustment unit, and the tilt adjustment unit adjusts the tilt angle of the blade so that the blade blown by the wind can apply the rotation force to the floating body.

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