Magnus wave power generation device

Abstract

To provide a Magnus wave power generating device that can resonate with waves by following large changes in the wave period. [Solution] The device main body 10 is configured as an integrated structure with a float section 12, a Magnus turbine power generation section 14, and a weight section 16 arranged in order from top to bottom. The weight section 16 includes a solid weight 16a and a water tank 16b2. A pump 26 adjusts the amount of water stored in the water tank 16b2 by supplying and discharging water surrounding the device main body 10 to and from the water tank 16b2. A wave height change detection section 36 detects changes in the height of the water surface surrounding the device main body 10 due to waves. From the changes in water surface height detected by the wave height change detection section 36, a control section 15 detects the period or frequency of a fundamental wave whose wave height value is determined to be equal to or greater than a predetermined value and whose occurrence frequency within a predetermined time is determined to be relatively high compared to waves of other periods, and drives the pump 26 to cause the natural period of the device main body 10 to follow the period or frequency of the detected fundamental wave.

Description

[Technical Field]

[0001] The present invention relates to a Magnus wave power generation device that converts wave energy from the sea, lakes, marshes, etc. into electric power by utilizing the Magnus effect. [Background technology]

[0002] The inventors of the present application have previously proposed a novel Magnus wave power generation device in Patent Document 1, and a resonance control method for a Magnus wave power generation device in Non-Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-17096 [Non-patent literature]

[0004] [Non-Patent Document 1] Paper "Resonance Control Method for a Point Absorber Wave Energy Converter with Magnus Effect-Based Turbine Generator" by K. Yamashita, S. Takekoshi, and S. Katsuki, presented at the International Conference on Electrical Machines and Systems (ICEMS 2023), Zhuhai, China, November 5-8, 2023 Summary of the Invention [Problem to be solved by the invention]

[0005] As described in Non-Patent Document 1, in point absorber-type power generation such as Magnus wave power generation, wave energy can be efficiently converted into electricity by resonating the movement of the floating body with the waves. Non-Patent Document 1 proposes a resonance control method using electric propulsion that utilizes turbine thrust. However, this resonance control method has a narrow control range and is unable to respond to large changes in wave period.

[0006] The present invention provides a Magnus wave power generation device that can resonate with waves by following large changes in the wave period. [Means for solving the problem]

[0007] This invention is configured as an integrated structure in which a float section, a Magnus turbine power generation section, and a weight section are arranged in the vertical direction and connected to each other in that order from top to bottom, the Magnus turbine power generation section comprises a Magnus turbine and a generator that are driven by wave power using the Magnus effect, the weight section comprises a solid weight and a water tank, and when immersed in water, the float section floats in the water with at least the upper part of the float section protruding from the water surface, and a device main body section mounted within the device main body section, which, when immersed in water, supplies water around the device main body section to the water tank or drains water from the water tank around the device main body section to adjust the amount of water contained in the water tank, thereby The device comprises a pump that varies the draft of the device main body, thereby varying the natural period of the up and down movement of the device main body underwater, a wave height change detection unit that is disposed separately from the device main body and detects changes in the height of the water surface around the device main body when it is submerged due to waves, and a control unit that, from the changes in water surface height detected by the wave height change detection unit, detects the period or frequency of a fundamental wave, which is determined to have a wave height value equal to or greater than a predetermined value and to occur relatively frequently within a predetermined time period compared to waves of other periods, and controls the pump to drive so that the natural period of the device main body follows the period or frequency of the detected fundamental wave.By adjusting the amount of water contained in the water tank to cause the natural period of the device main body to follow the period of the fundamental wave, the device main body can resonate with the frequently occurring waves and move up and down significantly, thereby obtaining a large power generation output. Furthermore, since the weight section comprises a solid weight and a water tank, the device main body can be made smaller (for example, the overall vertical length of the device main body can be shortened) compared to when the weight section is made up of only a water tank.

[0008] In this invention, the control unit may include a water volume characteristic memory unit that stores characteristics of the water volume of the water tank or a value equivalent to the water volume that realizes the natural period of the device main body corresponding to the period or frequency of the detected fundamental wave, and a water volume detection unit that detects the water volume of the water tank or a value equivalent to the water volume, and the control unit may read the water volume of the water tank or a value equivalent to the water volume that corresponds to the period or frequency of the detected fundamental wave from the water volume characteristic memory unit, and control the pump to drive so that the value of the water volume of the water tank or the value equivalent to the water volume detected by the water volume detection unit follows the water volume or the value equivalent to the water volume read from the water volume characteristic memory unit. In this way, the device main body can resonate with frequently occurring waves by detecting the water volume of the water tank or a value equivalent to the water volume, without directly detecting the draft of the device main body, which is moving up and down due to waves. In this case, the pump can be reversibly driven to supply water to and drain water from the water tank, and the water volume detection unit can detect a value corresponding to the water volume of the water tank by adding the amount of water supplied to the water tank from the pump and subtracting the amount of water drained from the water tank via the pump. This allows the device body to indirectly measure the water volume and control the device body to resonate with frequently occurring waves, even when the device body is swaying due to waves, causing the water in the tank to sway and making it difficult to directly measure the water volume of the water tank. Furthermore, in this case, the control unit can drive the pump in a draining direction based on a predetermined command to return the water tank to an initial state where no more water can be drained, and reset the detection value of the water volume detection unit. This allows the indirect calculation of the water volume of the water tank by subtracting the amount of water supplied from the amount of water drained, which can lead to an error between the actual water volume of the water tank and the calculated value over a long period of use. This error can be eliminated by returning the water tank to an initial state where no more water can be drained and resetting the detection value of the water volume detection unit.

[0009] In this invention, the pump can be arranged in the water tank or in a space adjacent to the water tank below the Magnus turbine power generation unit. In this way, the pump is arranged below the water surface when the device main body is immersed in water, and the weight of the pump can be used as part of the weight, contributing to maintaining a stable upright position of the device main body floating in the water.

[0010] In this invention, the wave height change detection unit may include a wave height meter placed floating on the water surface near where the device main body is placed, thereby making it possible to detect changes in the height of the water surface around the device main body even when the device main body is placed away from land.

[0011] In this invention, the control unit can control the pump to operate intermittently throughout the day. Since the fundamental wave period of ocean waves in oceans and lakes does not change rapidly (the fundamental wave period of ocean waves is usually in the range of several seconds to several tens of seconds), adjusting the draft intermittently throughout the day (for example, several times a day) allows the natural period of the device main body to follow the fundamental wave period. This reduces the power consumption of the pump compared to when the pump is operated continuously. [Brief explanation of the drawings]

[0012] [Figure 1] This figure shows the device main body and wave height change detection unit of the Magnus wave power generator in Figure 2, showing the device main body and wave height change detection unit in use when they are submerged in the sea, with a portion of the device main body broken away to show a schematic representation of the internal structure. [Figure 2] 1 is a diagram showing an embodiment of a Magnus wave power generator according to the present invention, showing the overall system configuration of the Magnus wave power generator in use. FIG. [Figure 3] 3 is a block diagram showing an embodiment of a control system for draft control by the control unit of FIG. 2. FIG. [Figure 4] FIG. 4 is a block diagram showing an example of a specific method for realizing the draft control of FIG. 3. [Figure 5] FIG. 4 is a block diagram showing another example of a specific method for realizing the draft control of FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the present invention will be described. Figure 2 shows an embodiment of a Magnus wave power generator according to the present invention, illustrating the overall system configuration of the Magnus wave power generator during operation. The Magnus wave power generator 1 comprises a main body 10, a wave height meter 36 (wave height change detector), and a control unit 15. The main body 10 is placed in the seawater 11 with its upper portion protruding from the sea surface 11a. The main body 10 houses a Magnus turbine power generation unit 14, a water tank 16b2, a pump 26, and other components (the detailed configuration of the main body 10 will be described later). The Magnus turbine power generation unit 14 converts the up and down motion of the main body 10 caused by waves into electrical energy using the Magnus effect. The natural period of the up and down motion of the main body 10 in the seawater 11 is adjusted by adjusting the amount of water stored in the water tank 16b2 using the pump 26 to adjust the draft of the main body 10. The lower end of the main body 10 is connected to an anchor 19 via a mooring wire 17. The anchor 19 is anchored to the seabed 13, allowing the device main body 10 to move vertically (up and down due to normal waves) while preventing lateral movement. The wave height meter 36 is floating on the sea surface 11a near the device main body 10. The wave height meter 36 and the device main body 10 are connected by a cable as needed, and power and signals are supplied to the wave height meter 36 through the cable. The wave height meter 36 detects changes in the height of the sea surface 11a due to waves. The control unit 15 detects the period or frequency of the fundamental wave from the changes in the height of the sea surface 11a detected by the wave height meter 36 and controls the pump 26 to drive the device main body 10 so that its natural period or natural frequency follows the detected period or frequency. This causes the device main body 10 to resonate with frequently occurring waves, causing large up and down movements, thereby enabling large power output from the Magnus turbine power generation unit 14. The device main body 10 is connected to land by a cable 21. Cable 21 contains a power transmission cable that transmits electricity generated by Magnus turbine power generation unit 14 to a land base, a power supply cable that supplies power required for the initial acceleration of Magnus turbine power generation unit 14 (see Patent Document 1) and for driving pump 26 from the base to device main body 10, and a signal cable that sends and receives signals between device main body 10 and the base. Control unit 15 can be built into device main body 10 or located at the base.The wave height meter 36 and the control unit 15 can be connected by wire or wirelessly. The device main body 10 can be equipped with a solar cell and a battery as needed. The power from the battery can be used as a power source for initial acceleration of the Magnus turbine power generation unit 14, a drive power source for the pump 26, and an operating power source for the wave height meter 36, control unit 15, etc. The battery can also be charged with the power generated by the Magnus turbine power generation unit 14 or the power generated by the solar cell. The wave height meter 36 can also be equipped with a solar cell and a battery, and the battery can be charged with the power generated by the solar cell and used as the operating power source for the wave height meter 36.

[0014] The configuration of the device main body 10 will be described with reference to Figure 1. The device main body 10 is configured as an integrated structure in which, from top to bottom, a float section 12, a Magnus turbine power generation section 14, and a weight section 16 are arranged and interconnected in the vertical direction, making their relative positions fixed (immovable). The device main body 10 is generally a vertically elongated concentric cylinder, with the Magnus turbine power generation section 14 located midway up and down having a radially bulging outer shape. The entire outer surface of the device main body 10 is made of a corrosion-resistant metal material such as stainless steel. The entire outer surface of the device main body 10 can also be painted. The upper and lower ends of the device main body 10 (the upper end of the float section 12 and the lower end of the weight section 16) are each formed in a tapered shape. The device main body 10 has a light (low density) upper portion made up of the float portion 12 and a heavy (high density) lower portion made up of the weight portion 16, so when it is dropped into the sea 11, it floats in the sea 11 with the float portion 12 on top and its longitudinal direction facing up and down (vertical). At this time, at least the upper portion of the float portion 12 protrudes above the sea surface 11a. The device main body 10 moves up and down in place due to waves 11b.

[0015] The float section 12 has a cavity 12b in a watertightly sealed housing 12a. The lower end of the float section 12 is fixedly connected to the upper surface of a structural part (fixed part, not shown) of the Magnus turbine power generation section 14.

[0016] The Magnus turbine power generating section 14 has a structure in which a Magnus turbine 18 (Magnus blades) driven by wave power using the Magnus effect and a power generating unit 20 (here, two units, one above the other) containing a generator driven by the Magnus turbine 18 are interconnected via bevel gears and speed change gears. The Magnus turbine power generating section 14 may be, for example, that described in Patent Document 1. The power generating unit 20 is fixed to the structural part of the Magnus turbine power generating section 14. The Magnus turbine 18 and the power generating unit 20 are surrounded by a reducer and diffuser 22. The reducer and diffuser 22 has a structure in which two truncated cones (roughly funnel-shaped) are joined together with their tops overlapping each other. The reducer and diffuser 22 is fixed to the structural part of the Magnus turbine power generating section 14 with the central axis of the truncated cone aligned with the central axis 10a of the device main body 10. A cavity 22b is formed on the inner periphery of the reducer and diffuser 22, communicating with the underwater sea 11 surrounding the device body 10. Openings 22c and 22d are formed at the upper and lower ends of the cavity 22b. The Magnus turbine 18 is disposed at the vertical center of the cavity 22b. The cross-sectional area of ​​the cavity 22b in the direction perpendicular to the axis is largest at the openings 22c and 22d at both vertical ends and narrowest at the vertical center. Therefore, the Magnus turbine 18 is disposed at a position where the flow velocity of seawater is highest (and therefore the driving energy is highest) as the device body 10 moves up and down due to waves 11b. The seawater flows in through the upper opening 22c and is discharged from the lower opening 22d (when the device body 10 rises relative to the seawater) or flows in through the lower opening 22d and is discharged from the upper opening 22c (when the device body 10 descends relative to the seawater) as the device body 10 moves up and down. Therefore, the reducer and diffuser 22 have the effect of increasing the power generation output of the power generation unit 20. The outer periphery of the reducer and diffuser 22 may be surrounded by a cylindrical structure made of stainless steel or the like, and the cylindrical structure may be fixed to the reducer and diffuser 22. The space between the cylindrical structure and the reducer and diffuser 22 may or may not be watertightly sealed.

[0017] The upper end of the weight section 16 is fixedly connected to the underside of the structural part of the Magnus turbine power generation section 14. The weight section 16 has a structure in which a solid weight 16a is arranged on the lower side and a cavity 16b, which is watertightly sealed by a housing 16c, is arranged on the upper side. The solid weight 16a can be made entirely of a metal block such as stainless steel. Alternatively, the solid weight 16a can be made by filling the internal space of the housing 16c, such as stainless steel, with a high-density substance such as metal particles. The cavity 16b is watertightly divided into upper and lower cavities 16b1 and 16b2 by a partition plate 24. The lower cavity 16b2 forms a water tank, and the upper cavity 16b1 forms the accommodation space for a pump (electric submersible pump) 26. The pump 26 is fixedly arranged on the upper surface of the partition plate 24. The pump 26 is a reversible pump that can reverse the inflow and outflow directions. An end opening 28a of a pipe 28 connected to one of the inlet and outlet ports of pump 26 passes through casing 16c and communicates with the underwater space 11 around device main body 10. An end opening 30a of a pipe 30 connected to the other inlet and outlet port of pump 26 passes through partition plate 24 and communicates with the bottom of water tank 16b2. When pump 26 is driven in one direction, it supplies seawater around device main body 10 to water tank 16b2 via pipe 28, and when driven in the reverse direction, it discharges seawater from water tank 16b2 to the area around device main body 10 via pipe 28. By adjusting the amount of seawater stored in water tank 16b2 in this way, the buoyancy of device main body 10 can be adjusted to vary its draft, and as a result, the natural period of the up and down motion of device main body 10 in the underwater space 11 can be varied. An air pipe 32 is installed in the device main body 10 along the axial direction of the device main body 10, connecting the water tank 16b2 to the outside air surrounding the float portion 12. The lower end opening 32a of the air pipe 32 passes through the housing 16c and connects to the top of the water tank 16b2. The upper end opening 32b of the air pipe 32 connects to the outside air surrounding the float portion 12. The air pipe 32 maintains a constant air pressure within the water tank 16b2. Note that while FIG. 1 shows the air pipe 32 installed with its middle portion exposed to the outside of the device main body 10, it can also be installed with its entire length, excluding the upper end opening 32b, housed within the device main body 10. A stabilizer 34 consisting of blades extending in the vertical direction is installed on the outer periphery of the float portion 12 and the weight portion 16.The stabilizer 34 allows the device main body 10 to move up and down stably in the sea 11.

[0018] A wave height meter 36 is placed in the sea 11 near where the device main body 10 is placed, floating on the sea surface 11a. The device main body 10 and the wave height meter 36 are placed separately (i.e., their relative positions are not fixed). However, the wave height meter 36 can be connected to the device main body 10 with a rope or the like to prevent it from moving. The wave height meter 36 measures changes in the height of the sea surface 11a caused by waves, for example, using a built-in acceleration sensor.

[0019] The control system for the pump 26 by the control unit 15 in Figure 2 will be described with reference to Figure 3. The frequency spectrum of the wave height data (data measuring changes in wave height in real time) measured by the wave height meter 36 is analyzed by the fast Fourier transform unit 40. From the analyzed frequency spectrum, the fundamental wave detection unit 42 detects the fundamental wave, i.e., a wave component whose wave height is equal to or greater than a predetermined value and whose occurrence frequency within a predetermined time is determined to be relatively high compared to waves of other frequencies. The reason for limiting the wave height to waves whose wave height is equal to or greater than a predetermined value is that even if the occurrence frequency is high, if the wave height is low, the power obtained through power generation will be small or no power will be generated at all. The detection of the fundamental wave by the fundamental wave detection unit 42 can be performed, for example, as follows: From the frequency spectrum analyzed by the fast Fourier transform unit 40, the frequency component of the wave whose wave height is equal to or greater than a predetermined value within a set time and whose wave height is the highest is detected. This operation is repeated multiple times. Among the frequency components detected for each of these multiple operations, a frequency component that is determined to have a relatively high occurrence frequency compared to other frequency components (for example, the frequency component with the highest occurrence frequency, the frequency component obtained by averaging frequency components whose occurrence frequency is equal to or greater than a predetermined threshold, or the median frequency component of a frequency component band whose occurrence frequency is equal to or greater than a predetermined threshold) is detected as a fundamental wave. The draft target value calculation unit 44 calculates the draft H of the device main body 10 in order to match the natural period of the up and down movement of the device main body 10 in the sea 11 with a period corresponding to the frequency of the detected fundamental wave (the reciprocal of the frequency of the fundamental wave). 0ref is calculated as the control target value. This control target value is given by equation (1) which is a simplified formula for the relationship between the draft and natural period of an object floating on the water surface. H0ref =g(Tw / 2π) 2 ……(1) where g is the gravitational acceleration, Tw is the period of the fundamental wave The error detection unit 46 detects the draft target value H 0ref is compared with the actual draft H0 of the device main body 10, and the deviation ΔH0 is detected. A PI (proportional integral) controller 48 drives the water supply / drainage system 50 (pump 26) to adjust the amount of water stored in the water tank 16b2 so that the deviation ΔH0 becomes zero. As a result of this control, the device main body 10 resonates with the frequently occurring waves and moves up and down significantly, resulting in a large power output from the Magnus turbine power generation unit 14. Because the period of the fundamental wave does not change suddenly in the ocean or lakes and marshes, this control can be performed intermittently throughout the day (several times a day).

[0020] Here, an example of setting the weight of solid weight 16a and the capacity of water tank 16b2 will be described. The weight of solid weight 16a and the capacity of water tank 16b2 can be set based on the range of fluctuation of the fundamental wave period Tw of the waves assumed to occur in the water area where device main body 10 is placed. That is, according to equation (1), in order for device main body 10 to resonate with the fundamental wave of the waves, the draft H0 must be shallow (weight portion 16 must be lighter) when the fundamental wave period Tw is short, and the draft H0 must be deep (weight portion 16 must be heavier) when the fundamental wave period Tw is long. Therefore, solid weight 16a is set to a weight that can achieve the shortest period within the assumed range of fluctuation of the fundamental wave period Tw when water tank 16b2 is in its initial state where it cannot drain any more water (when water tank 16b2 can be made the lightest). Furthermore, the capacity of water tank 16b2 is set to a value that allows realization of the longest period of the assumed fluctuation range of the period Tw of the fundamental wave when the water storage capacity is at its maximum (when water tank 16b2 can be made the heaviest).

[0021] The control system in Figure 3 mentioned above is the draft target value H 0refThe draft of the device main body 10 is adjusted based on the deviation ΔH0 between the draft H0 and the actual draft H0 of the device main body 10. However, it is difficult to directly detect the draft H0 of the device main body 10, which moves up and down due to waves. Therefore, a method for adjusting the draft of the device main body 10 without directly detecting the draft H0 will be described. Figure 4 shows an example of this method. This method measures the amount of water entering and leaving the water tank 16b2 (water supply amount - water discharge amount), detects this measurement value as a value equivalent to the water storage amount of the water tank 16b2, and adjusts the draft H0 of the device main body 10. In Figure 4, the water storage amount characteristic memory unit 52 stores characteristic data (data indicating the amount of water entering and leaving the water tank 16b2 to achieve the specified draft H0) as a lookup table or function, which shows the relationship between the amount of water entering and leaving the water tank 16b2 actually measured (or calculated) and the draft H0 of the device main body 10. 0ref When the target draft value H 0ref The amount of water flowing in and out of the water tank 16b2 is W 0ref is read out as the control target value. Meanwhile, the water supply / discharge meter 54 (water storage volume detection unit) detects the value (water inflow / outflow volume) W0 obtained by adding the amount of water supplied from the pump 26 to the water tank 16b2 and subtracting the amount of water drained from the water tank 16b2 via the pump 26 as a value corresponding to the water storage volume of the water tank 16b2. The error detection unit 56 detects the water inflow / outflow volume target value W 0refis compared with the detected water inflow / outflow volume W0, and the deviation ΔW0 is detected. Pump driver 58 reversibly drives pump 26 so that deviation ΔW0 becomes zero. This control allows device main body 10 to resonate with a frequently occurring wave. With this method, even if device main body 10 is swayed by waves, causing the water in tank 16b2 to sway as well, making it difficult to directly measure the water storage volume of water tank 16b2, it is possible to indirectly measure the water storage volume of water tank 16b2 by measuring the water inflow / outflow volume W0 corresponding to the water storage volume. Note that this method of calculating water inflow / outflow volume W0 by subtracting the water supply volume from the water discharge volume may result in an error in the detected value relative to the actual water storage volume of water tank 16b2 over long periods of use. In this regard, for example, based on an instruction issued automatically at an appropriate timing (at predetermined time intervals, when the amount of change in the fundamental wave component detected by the fundamental wave detection unit 42 exceeds a predetermined threshold, etc.) or issued based on an instruction operated by an operator, the pump 26 is driven in the drain direction to return the amount of water remaining in the water tank 16b2 to an initial state in which no more water can be drained, and the detection value of the water supply / drainage meter 54 is reset before measurement is resumed, thereby eliminating the error.

[0022] Figure 5 shows another example of a method for adjusting the draft of the device main body 10 without directly detecting the draft H0. This involves measuring the water level of the water tank 16b2, detecting the measured value as a value equivalent to the amount of water stored in the water tank 16b2, and adjusting the draft of the device main body 10. In Figure 5, the water storage characteristic memory 60 stores characteristic data (data indicating the water level of the water tank 16b2 to achieve the specified draft H0) that indicates the relationship between the water level of the water tank 16b2 actually measured (or calculated) and the draft H0 of the device main body 10, as a look-up table or function. The period Tw of the fundamental wave is detected and the target draft value H 0ref When the target draft value H 0ref The water level L of the water tank 16b2 is 0refis read out as a control target value. Meanwhile, water level meter 62 (water volume detection unit) detects the water level L0 of water tank 16b2 as a value corresponding to the amount of water stored in water tank 16b2. As water level meter 62, various types of water level meter can be used, such as a float type that measures the height position of a float floating on the surface of water tank 16b2, an ultrasonic type that emits ultrasonic waves from above in water tank 16b2 toward the liquid surface and measures the time it takes for them to be reflected by the liquid surface and return, or a water pressure type that measures the water pressure at the bottom of water tank 16b2. Error detection unit 64 detects the water level target value L 0ref is compared with the detected water level L0, and the deviation ΔL0 is detected. The pump drive unit 66 reversibly drives the pump 26 so that the deviation ΔL0 becomes 0. This control allows the device main body 10 to resonate with waves that occur frequently.

[0023] As can be seen from equation (1), there is a one-to-one correspondence between the draft H0 of the device main body 10 and the natural frequency or natural period, so the characteristic data stored in the water volume characteristic storage unit 52 in Fig. 4 can also be data showing the relationship between the amount of water entering and leaving the water tank 16b2 (a value corresponding to the amount of water stored in the water tank 16b2) and the natural frequency or natural period of the device main body 10 (characteristic data showing the relationship between the amount of water entering and leaving the water tank 16b2 to achieve the specified natural frequency or natural period). In this case, the target water volume W is stored in the water volume characteristic storage unit 52 using the frequency or period of the fundamental wave detected by the fundamental wave detection unit 42 (Fig. 3). 0ref 4 can be performed by reading out the characteristic data stored in the water storage characteristic storage unit 52 in FIG. 5. Similarly, the characteristic data stored in the water storage characteristic storage unit 52 in FIG. 5 can be data showing the relationship between the water level of the water tank 16b2 and the natural frequency or natural period of the device main body 10 (data showing the relationship between the water level of the water tank 16b2 to achieve the specified natural frequency or natural period). In this case, the water level target value L is read from the water storage characteristic storage unit 52 using the frequency or period of the fundamental wave detected by the fundamental wave detection unit 42 (FIG. 3). 0ref can be read out and the control shown in FIG.

[0024] In the above embodiment, the weight unit has a solid weight disposed below and a water tank disposed above. However, the positions of the solid weight and water tank can be reversed, with the solid weight disposed above and the water tank disposed below. The solid weight and water tank can also be disposed concentrically (for example, a ring-shaped solid weight made of a metal block or the like is disposed on the outer periphery, with the space inside the weight used as the water tank, or conversely, a solid weight is disposed in the center, with the space outside the weight used as the water tank). In the above embodiment, the pump is disposed above the water tank. Alternatively, the pump can be submerged in the water tank or disposed in a space below the water tank. In the above embodiment, the wave height change detection unit is configured as a wave height meter equipped with an acceleration sensor floating on the sea surface. However, the wave height change detection unit can also be configured as a radar wave height meter mounted on a pole or pedestal protruding above the sea surface, installed on the coast or fixed to the seabed. [Explanation of symbols]

[0025] 1...Magnus wave power generation device, 10...device main body, 10a...central axis of device main body, 11...underwater (underwater), 11a...sea surface (water surface), 11b...wave, 12...float part, 12a...casing, 12b...air chamber, 13...seabed, 14...Magnus turbine power generation part, 15...control part, 16...weight part, 16a...solid weight, 16b...cavity, 16b1...cavity (pump accommodating space), 16b2...cavity (water tank), 16c...casing, 17...mooring wire, 18...Magnus turbine, 19...anchor, 20...power generation unit (with built-in generator), 21...cable, 22...reducer and diffuser, 22b...cavity, 22c, 22d...opening, 24...partition plate, 26...pump (electric power generation) submersible pump), 28, 30...submersible pump piping, 28a, 30a...submersible pump piping end opening, 32...air pipe, 32a...lower end opening of air pipe, 32b...upper end opening of air pipe, 34...stabilizer, 36...wave height meter (wave height change detection unit), 40...fast Fourier transform unit, 42...fundamental wave detection unit, 44...draft target value calculation unit, 46...error detection unit, 48...PI controller, 50...water supply / drainage system, 52...water storage volume characteristics memory unit, 54...water supply / drainage meter (water storage volume detection unit), 56...error detection unit, 58...pump drive unit, 60...water storage volume characteristics memory unit, 62...water level meter (water storage volume detection unit), 64...error detection unit, 66...pump drive unit

Claims

1. a device body section that is configured as an integrated structure in which a float section, a Magnus turbine power generating section, and a weight section are arranged in a vertical direction and connected to each other in that order from top to bottom, the Magnus turbine power generating section includes a Magnus turbine and a generator that are driven by wave power using the Magnus effect, the weight section includes a solid weight and a water tank, and when placed in water, the device body section floats in the water with at least the upper part of the float section protruding from the water surface; a pump mounted in the device main body, which, when the device main body is immersed in water, supplies water around the device main body to the water tank or drains water from the water tank to the device main body, thereby adjusting the amount of water contained in the water tank, thereby varying the draft of the device main body and thereby varying the natural period of the up and down movement of the device main body in water; a wave height change detection unit that is disposed separately from the device main body and detects a change in height of the water surface around the device main body that is immersed in water due to waves; a control unit that detects a period or frequency of a fundamental wave, based on the change in water surface height detected by the wave height change detection unit, and determines that the wave component has a wave height value equal to or greater than a predetermined value and appears more frequently within a predetermined time period than waves of other periods, and controls the pump to drive so that the natural period of the device main body follows the period or frequency of the detected fundamental wave; A Magnus wave power generation device having the same.

2. the control unit includes a water volume characteristic storage unit that stores the characteristics of the water volume of the water tank or a value corresponding to the water volume that realizes the natural period of the device main body corresponding to the period or frequency of the detected fundamental wave, and a water volume detection unit that detects the water volume of the water tank or a value corresponding to the water volume; The control unit reads out the water volume of the water tank or a value corresponding to the water volume, which corresponds to the period or frequency of the detected fundamental wave, from the water volume characteristic storage unit, and controls the pump to drive so that the water volume of the water tank or the value corresponding to the water volume detected by the water volume detection unit follows the water volume or the value corresponding to the water volume read out from the water volume characteristic storage unit. The Magnus wave power generation device according to claim 1.

3. The pump is reversibly driven to supply water to the water tank and drain water from the water tank, The water storage amount detection unit detects a value obtained by adding the amount of water supplied from the pump to the water tank and subtracting the amount of water drained from the water tank via the pump as a value corresponding to the amount of water stored in the water tank. The Magnus wave power generation device according to claim 2.

4. The control unit drives the pump in the drain direction based on a predetermined instruction to return the water tank to an initial state in which no more water can be drained, and also performs control to reset the detection value of the water storage amount detection unit. The Magnus wave power generator according to claim 3.

5. 2. The Magnus wave power generator according to claim 1, wherein the pump is disposed in the water tank or in a space adjacent to the water tank below the Magnus turbine power generation unit.

6. 2. The Magnus wave power generator according to claim 1, wherein the wave height change detection unit comprises a wave height meter arranged floating on the water surface near where the device main body is immersed.

7. 2. The Magnus wave power generator according to claim 1, wherein the control unit controls the pump to be driven intermittently throughout the day.

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