Energy supply unit and power generation system

Abstract

To provide an energy supply unit and a power generation system capable of reducing a safety area when a kite falls.SOLUTION: The energy supply unit comprises a kite and an energy generation unit. The energy supply unit supplies the generator with energy. The kite includes a flying object, and a control line and a power line connected to the flying object. The flying object can be made to fly on a figure-of-eight trajectory using wind power and a control rope. The energy generation unit includes a movable body and a restoring force mechanism. The movable body supports the power cable. The movable body is configured to be capable of reciprocating in a first direction and a second direction opposite to the first direction in accordance with a magnitude of a traction force received from a kite flying in a figure-eight trajectory. The restoring force mechanism applies a restoring force smaller than a first traction force received from the kite and larger than a second traction force smaller than the first traction force received from the kite to the movable body. The energy generation unit generates energy using the reciprocating motion of the movable body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a kite-based energy supply unit and power generation system. [Background technology]

[0002] A power generation device that generates energy using a kite (a system in which a flying object is attached to a rope) is known as an airborne wind energy system. In airborne wind power generation, the flying object is flown into the air, and the wind power that the flying object receives is converted into energy. Airborne wind power generation is broadly divided into those in which the power generation mechanism is installed on the ground and those in which the power generation mechanism is installed on the flying object (see Non-Patent Document 1).

[0003] One type of power generation device that has been put into practical use and has a power generation mechanism installed on the ground is the pumping cycle system. In this system, when a kite catches the wind and rises, a cable is pulled out, and energy is extracted by rotating a drum around which the cable is wound. When the cable has been pulled out to a predetermined length, the kite is lowered. At this time, drag is minimized by, for example, giving the kite a negative angle of attack, thereby minimizing the energy required to reel in the cable. As a result, the amount of energy generated when the cable is pulled out is greater than the amount of energy consumed when reeling it in, and net energy can be generated in this one cycle (see Patent Documents 1 to 5).

[0004] Other methods for extracting energy from a generator fixed on the ground include a method in which wind power is converted into torsional energy using multiple blades (see Patent Document 6), a method in which the figure-eight cycle of a kite is converted into the left and right movement of a lever (see Patent Document 7), and a method in which kites are attached to both ends of a vertical axis wind turbine (see Patent Document 8).

[0005] Another method for extracting energy from a generator fixed to the ground is towing a vehicle with a generator mounted on a kite. In this method, the generator is not fixed to a specific location on the ground, as opposed to the above methods in which the generator is fixed to a specific location on the ground. In this method, energy is extracted from the rotating mechanism of the wheels of the vehicle towed by the kite (see Patent Documents 9 and 10).

[0006] Of the above-mentioned methods, those other than the pumping cycle method have not yet been put to practical use due to issues with structural stability and efficiency. For example, the wind turbine device described in Patent Document 6, which combines multiple ropes and flexible wings, has a structural stability issue in that it is less able to withstand strong winds than a conventional kite used in the pumping cycle method. Similarly, the wind power generation system described in Patent Document 8 also has a similar structural stability issue with the turbine unit attached to the kite. In the wind energy recovery device described in Patent Document 7, which drives a power lever by moving a kite back and forth in a roughly arc-shaped trajectory, the theoretically contributing pulling force to energy generation is smaller than that of the pumping cycle method, which utilizes pulling force downward and upward, and is therefore less efficient. For this reason, the pumping cycle method and the vehicle towing methods described in Patent Documents 9 and 10 are practical methods. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-232461 [Patent Document 2] Special Publication No. 2013-535612 [Patent Document 3] Special Publication No. 2018-502799 [Patent Document 4] Special Publication No. 2019-532216 [Patent Document 5] Japanese Patent Publication No. 2020-94521 [Patent Document 6] Japanese Patent Application Publication No. 2022-34899 [Patent Document 7] International Publication No. 2013 / 094623 [Patent Document 8] Japanese Patent Application Laid-Open No. 2014-51991 [Patent Document 9] Special Publication No. 2010-523865 [Patent Document 10] Special Publication No. 2016-502625 [Non-patent literature]

[0008] [Non-Patent Document 1] Antonello Cherubini, Andrea Papini, Rocco Vertechy, Marco Fontana, "Airborne Wind Energy System: A review of the technologies," Renewable and Sustainable Energy Reviews, Vol.51, 2015, pO2461-1476, https: / / doi.org / 10.1016 / j.rser.2015.07.053 Summary of the Invention [Problem to be solved by the invention]

[0009] The pumping cycle systems described in Patent Documents 1 to 5 and the vehicle towing systems described in Patent Documents 9 and 10 require a large safety area to ensure the energy produced. In other words, the pumping cycle system requires the cable to be stretched to a certain length, so considering the safety area against the falling of the flying object and cable, an area of ​​at least several hundred meters must be secured on the ground, resulting in a large area on the ground. Furthermore, the vehicle towing system requires rails for the vehicle to travel around, and also requires a safety area against the falling of the flying object and cable. Furthermore, the pumping cycle system has issues such as intermittent output, which increases the cost of auxiliary mechanisms such as batteries and flywheels; the risk of a crash due to the rapid change in the flying object's altitude; and the difficulty of coordinating the area with other flying objects in the sky due to the inconsistent position of the flying object.

[0010] In view of the above circumstances, an object of the present invention is to provide an energy supply unit and a power generation system that can reduce the safety area in the event of a kite falling. [Means for solving the problem]

[0011] To achieve the above object, an energy supply unit according to one embodiment of the present invention includes a kite and an energy generating unit. The energy supply unit supplies energy to the generator. The kite has a flying body, a control cable, and a power cable, which are connected to the flying body, and is configured to fly in a figure-eight trajectory using the control cable by utilizing wind power. The energy generating unit includes a movable body and a restoring force mechanism. The movable body supports the power cable and is configured to be able to reciprocate in a first direction and a second direction opposite to the first direction depending on the magnitude of the pulling force received from the kite flying in a figure-eight trajectory. The restoring force mechanism applies a restoring force to the movable body that is smaller than a first tractive force received from the kite and larger than a second tractive force received from the kite that is smaller than the first tractive force. The energy generating unit generates the energy using the reciprocating motion of the movable body.

[0012] With this configuration, the kite flying in an eight-shaped trajectory is used to reciprocate the movable body, which allows for efficient output of power and reduces the range of movement of the movable body, thereby reducing the necessary safety area in case the kite falls.

[0013] The first traction force is a traction force generated when the flying body descends on the figure-eight trajectory, and the second traction force is a traction force generated when the flying body ascends on the figure-eight trajectory, and the restoring force mechanism may impart the restoring force to the movable body when the second traction force acts on the movable body, which moves in the first direction due to the first traction force, thereby moving the movable body in the second direction.

[0014] The restoring force mechanism may be a spring mechanism.

[0015] The energy generating unit may further include a transmission mechanism that converts one of the first and second directional movements of the movable body into energy of movement in the other direction and supplies the energy to the generator.

[0016] The restoring force mechanism may not apply the restoring force to the movable body until the flying object takes an eight-shaped trajectory, and after the flying object takes an eight-shaped trajectory, may apply the restoring force to the movable body when the flying object rises on the eight-shaped trajectory.

[0017] The flying object may follow a figure-eight trajectory by self-excited oscillation.

[0018] The movable body may be a reel around which the power cable is wound, and may rotate in the first direction to unwind the power cable and rotate in the second direction to wind up the power cable.

[0019] The energy generating unit may further include a linear rail that guides movement of the movable body, and the movable body may be a slider that linearly reciprocates on the rail in the first direction and the second direction.

[0020] The control rope has a first control rope and a second control rope, each connected to the flying object, and the flying object may fly in an eight-shaped trajectory in the air by changing the rope length difference, which is the difference between the length of the first control rope and the length of the second control rope.

[0021] The fulcrum of the power rope may be located above and upwind of the fulcrum of the control rope.

[0022] In order to achieve the above object, a power generation system according to one embodiment of the present invention includes the above energy supply unit and a generator to which the energy is supplied from the energy supply unit.

[0023] The power generation system may further include a control unit capable of causing the flying object to fly in an eight-figure trajectory in the air, the power cable being connected to the energy generating unit, and the control cable being connected to the control unit.

[0024] In order to achieve the above object, a power generation system according to one embodiment of the present invention includes the above energy supply unit and a control unit. The control unit is connected to the control line and is capable of causing the flying object to fly in an eight-shaped trajectory in the air. [Effects of the Invention]

[0025] According to the present invention, an energy supply unit and a power generation system can be provided that can reduce the safety area in the event of a kite falling.

[0026] The effects described here are not necessarily limited to those described herein, and may be any of the effects described in this disclosure. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1A is a schematic perspective view of a power generation system according to each embodiment of the present invention, and FIG. 1B is a schematic side view of the power generation system according to each embodiment. [Figure 2] FIG. 2 is a block diagram illustrating the functional configuration of a power generation unit of the power generation system according to the first embodiment. [Figure 3] FIG. 2 is a schematic diagram of a power generation unit of the power generation system according to the first embodiment. [Figure 4] (A) to (C) are oblique views of the energy generation unit included in the power generation unit of the first embodiment, where (A) is a diagram explaining the movement in kite control mode (when adjusting the length), (B) is a diagram explaining the movement when the power rope is pulled out in power generation mode, and (C) is a diagram explaining the movement when the power rope is wound up in power generation mode. [Figure 5] FIG. 10(A) is a block diagram showing the functional configuration of a power generation unit according to a second embodiment, and FIG. 10(B) is a schematic diagram of the power generation unit. [Figure 6] (A) and (B) are oblique views of an energy generation unit included in a power generation unit according to a second embodiment, where (A) is an oblique view illustrating the movement of the power cable when it is pulled out in power generation mode, and (B) is an oblique view illustrating the movement of the power cable when it is wound up in power generation mode. [Figure 7] FIG. 10(A) is a block diagram showing the functional configuration of a power generation unit according to a third embodiment, (B) is a schematic side view of the power generation unit, and (C) is a schematic top view of the power generation unit. [Figure 8] (A) is a diagram explaining the kite's figure-eight trajectory, and (B) is a diagram showing the forces acting on the right and left control lines when the kite flies in the figure-eight trajectory. [Figure 9] 10(A) and 10(B) are diagrams for explaining the fulcrum O2 of the power rope and the fulcrum O1 of the control rope. [Figure 10] (A) shows the trajectory of the end points of the right control rope and the left control rope, and the trajectory of the midpoint of these end points, (B) shows the change in force at the midpoints, and (C) shows the change in length from the fulcrum of the power rope to the midpoint. [Figure 11] 10(A) and 10(B) are schematic diagrams of a power generation system according to a modified example, and 10(C) is a schematic diagram of a power generation system according to the first to third embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, mutually orthogonal X-, Y-, and Z-axes may be set. The XY plane corresponds to the horizontal plane, and the Z-axis direction corresponds to the vertical direction. Also, the same reference numerals are used for components already described, and their description may be omitted. In drawings including an energy supply unit, the direction of the wind W used for power generation when projected onto a horizontal plane generally coincides with the positive direction of the X-axis. Also, although specific numerical values ​​may be given in the following description, these are merely examples and are not limited to these numerical values.

[0029] First Embodiment <<Overall configuration of the power generation system>> FIG. 1(A) is a schematic perspective view of a power generation system 1 according to a first embodiment of the present invention, and FIG. 1(B) is a schematic side view of the power generation system 1. The power generation system 1 generates power (electrical energy) by utilizing wind force received by a flying object 20 of a kite 2. As shown in FIGS. 1(A) and 1(B), the power generation system 1 includes an energy supply unit 3, a generator 52, and a control unit 4. The energy supply unit 3 includes a kite 2 and an energy generating unit 30. The energy generating unit 30 and the generator 52 constitute a power generation unit 5. The kite 2 includes a flying object 20, a control cable 21, and a power cable 23.

[0030] In the power generation system 1, the flying object 20 is caused to fly on a horizontal figure-eight trajectory (hereinafter simply referred to as the "figure-eight trajectory"), and the reciprocating motion of a movable body (described later) constituting part of the energy generation unit 30 is converted into electricity using the figure-eight trajectory. The power generation unit 5 is placed on the control unit 4. The control unit 4 is installed on the ground G.

[0031] The power generation system 1 may be installed on a support placed on the ground G. The support includes a base placed on the ground G and a rotary table attached to the base so as to be rotatable around the Z axis. The rotary table allows the orientation of the power generation system 1 to be changed. By rotating the rotary table, the orientation of the power generation system 1 can be adjusted so that the kite 2 is positioned downwind with respect to the control unit 4 and the power generation unit 5. The orientation of the power generation system 1 is adjusted so that the direction of the wind W coincides with the pulling direction of the kite 2.

[0032] In the power generation system 1, the flying object 20 is adjusted by the control unit 4 to oscillate in a figure-eight trajectory in the air or to oscillate self-excitedly. In the power generation system 1, wind power is utilized by the control unit 4 to make the flying object 20 fly in a figure-eight trajectory, thereby obtaining a large force. This force is then used to reciprocate a movable object (in this embodiment, a reel 60, described later) to which a power rope 23 connected to the flying object 20 is connected, thereby efficiently generating electricity. In this embodiment and in the second and third embodiments described later, an example in which the flying object is adjusted to oscillate self-excitedly is described.

[0033] In the power generation system 1 of this embodiment, the control unit 4 adjusts the cable length so that the kite 2 flies in the air in a figure-eight trajectory (kite control mode). Then, when the flying object 20 begins to self-oscillate and continues to trace a horizontal figure-eight trajectory, the control unit 4 stops controlling the kite 2 and switches to power generation by the power generation unit 5 (power generation mode). In kite control mode, the power generation unit 5 is not driven so that power generation does not occur. In power generation mode, the power generation unit 5 is driven so that power generation occurs. Note that if a gust of wind occurs during power generation mode, for example, the control unit 4 may control the kite to keep the kite flying. In the following explanation, the term "power generation mode" refers to a power generation mode in which there are no gusts of wind, i.e., a steady-state power generation mode in which kite control by the control unit 4 is not required.

[0034] <<Each component of the power generation system>> The power generation system 1 includes a kite 2, an energy generating unit 30, a generator 52, and a control unit 4. The energy generating unit 30, the generator 52, and the control unit 4 are installed on the ground. Fig. 2 is a functional block diagram of the power generation unit 5, Fig. 3 is a schematic diagram showing a more detailed configuration of the power generation unit 5, and Figs. 4(A) to (C) are perspective views of the energy generating unit 30 included in the power generation unit 5.

[0035] [kite] As shown in FIG. 1(A), the kite 2 has a flying body 20 and a control line 21 and a power line 23 connected to the flying body 20. The control line 21 has a left control line 21L as a first control line and a right control line 21R as a second control line. Hereinafter, when there is no need to distinguish between the left control line 21L and the right control line 21R, they will be referred to as the control line 21. The control line 21 is connected to the control unit 4. The power line 23 is connected to the power generation unit 5. In the kite control mode, the power generation system 1 uses the control unit 4 to change the line length difference between the length of the left control line 21L and the length of the right control line 21R (described later) to adjust the line lengths so that the kite 2 flies in an eight-shaped trajectory in the air.

[0036] (flying object) From the viewpoint of flying the flying object 20 in a horizontal figure-eight trajectory, it is preferable to use a flying object having an anhedral angle and excellent maneuverability, and also to use a flying object having a large lift-to-drag ratio and a large lift force itself. Furthermore, it is preferable to use a flexible wing for the flying object 20 from the viewpoint of suppressing the Yijing during crash.

[0037] (control cable) The control rope 21 controls the movement of the flying object 20. By driving the control rope 21 with the control unit 4, the flying object 20 can be made to fly in a figure-eight trajectory.

[0038] As shown in FIG. 1(A), one end of each of the left control rope 21L and the right control rope 21R is connected to the flying object 20, and the other end is connected to the control unit 4. In this embodiment, the number of control ropes is two, but it may be two or more. The control rope 21 consists of a control rope main thread 211 that rises from the ground side, and multiple control rope sub-threads 212 that branch off from this and are connected to the flying object 20. The connection points between the control rope main thread 211 and the control rope sub-threads 212 are called thread loops 213.

[0039] When generating power using the power generation system 1 of this embodiment, the length of the control cable 21 can be approximately several tens of meters, for example, approximately 65 meters. Since excessively long cables can cause tangles, a length of approximately several tens of meters is preferable to prevent tangles. In contrast, in pumping cycle systems, the cable length is generally several hundred meters to approximately 1 km. The power generation system 1 of the present invention can significantly reduce the required safety zone (hereinafter simply referred to as the "safety zone") to prevent kite falls compared to pumping cycle systems. Furthermore, under Japan's aviation law, the launch of a flying object above 150 meters (250 meters elsewhere) requires the submission of a flight report. However, the power generation system 1 allows the flying object 20 to fly at an altitude of 150 meters or less, as required by the aviation law, thereby easing restrictions on the installation location of the power generation system 1.

[0040] (power cable) As shown in FIG. 1(A), one end of the power rope 23 is connected to the flying object 20 via the control rope 21, and the other end is connected to the energy generating unit 30. More specifically, the other end of the power rope 23 is connected to and supported by a reel 60 (described later) that constitutes part of the energy generating unit 30. The power rope 23 has a Y-shape. The power rope 23 is made up of a single main power rope thread 231 that rises from the ground side, and two sub-power rope threads 232 that branch off at a branch point 233 and are each connected to the joining points 213 of the left control rope 21L and the right control rope 21R.

[0041] In this embodiment, the power rope 23 is Y-shaped and made up of the main power rope thread 231 and two sub power rope threads 232, but is not limited to this configuration. For example, the power rope may be made up of a single rope, one end of which is directly connected to the center of the flying object 20 and the other end of which is connected to the energy generating unit 30, as long as the power rope is configured to be pulled by the movement of the flying object.

[0042] However, as in this embodiment, it is preferable to use a Y-shaped power rope, with one end of a single main power rope 231 connected to the energy generating unit 30, and two sub-power ropes 232 branching from the other end of the main power rope 231, each connected to the connection points 213 of the left control rope 21L and the right control rope 21R. This configuration makes it possible to prevent the power rope 23 from significantly suppressing the figure-eight motion of the kite, including self-excited vibrations when only the two control ropes 21 and the flying object 20 are present. Furthermore, using a Y-shaped power rope provides two connection points with the flying object 20, which is desirable from the perspective of redundancy.

[0043] In the power generation system 1, the reel 60 of the energy generating unit 30 is caused to reciprocate (reciprocate in the rotational direction in this embodiment) using a mechanism in which the length and tension of the power rope 23 change depending on the relative positional relationship between the energy generating unit 30 and the flying object 20. The energy of this reciprocating motion is then used to generate mechanical kinetic energy (hereinafter sometimes referred to as "energy" or "mechanical energy") that serves as the power to operate the generator 52.

[0044] 1(B) and 3, the point (support point) where the power rope 23 comes into contact with a pulley 56 (described later) that supports the power rope 23 and is provided between the reel 60 and the flying object 20 is referred to as the fulcrum O2 of the power rope 23. In this specification, the "length of the power rope (rope length)" refers to the length of the power rope 23 from the fulcrum O2 to the branch point 233.

[0045] (About the figure-eight orbit) FIG. 8(A) is a schematic diagram for explaining the figure-eight trajectory 10 of the flying object 20, and FIG. 8(B) is a schematic diagram showing the forces (tension) acting on the right control rope 21R and the left control rope 21L when the flying object 20 flies on the figure-eight trajectory 10. When the flying object 20 flies on the figure-eight trajectory, changes in tension occur in the right control rope 21R and the left control rope 21L. As the flying object 20 rises due to wind force, tension always acts on the control rope 21, but large tension acts on the control rope 21 on the figure-eight trajectory 10, especially when the flying object 20 descends.

[0046] As shown in Figures 8(A) and 8(B), near the descent position a, where the flying object 20 descends from left to right in the center of the figure-eight trajectory 10, the tension acting on the left control rope 21L and the right control rope 21R increases. Furthermore, the tension acting on the left control rope 21L is greater than the tension acting on the right control rope 21R, resulting in a difference in tension between the left and right. Near the descent position c, where the flying object 20 descends from right to left in the center of the figure-eight trajectory 10, the tension acting on the left control rope 21L and the right control rope 21R increases. Furthermore, the tension acting on the right control rope 21R is greater than the tension acting on the left control rope 21L, resulting in a difference in tension between the left and right. In contrast, near the ascent position b and near the ascent position d, where the flying object 20 ascends from bottom to top, the tension acting on the left control rope 21L and the right control rope 21R decreases, and the difference in tension between the left and right is also small.

[0047] The difference in tension between the left control rope 21L and the right control rope 21R near the descent point a and c is thought to depend on the distance between the flying object 20 and the fulcrum (described later) of each of the right control rope 21R and the left control rope 21L, in other words, the length of the left control rope 21L and the length of the right control rope 21R, and this is thought to be one of the mechanisms by which self-excited vibration occurs. Note that the mechanism of self-excited vibration has not been fully elucidated, and it is highly likely that it also depends on the deformation of the kite itself and the aerodynamic forces generated by it, making it a more complex mechanism.

[0048] In the figure-eight trajectory 10 shown in FIG. 8(A), as the flying object 20 ascends due to wind force, tension is always exerted on the power rope 23 connected to the flying object 20. However, on the figure-eight trajectory 10, particularly when the flying object 20 descends (passing through the descending vicinity a or c), a relatively large tension is exerted on the power rope 23. On the other hand, when the flying object 20 ascends (passing through the ascending vicinity b or d), a relatively small tension is exerted on the power rope 23. In the power generation system 1, when the flying object 20 descends on the figure-eight trajectory, the tension acting on the power rope 23 increases, resulting in a relatively large traction force (referred to as the first traction force), and when the flying object 20 ascends, the tension acting on the power rope 23 decreases, resulting in a relatively small traction force (referred to as the second traction force). This is utilized to control the direction of movement of the reel 60. The second traction force is smaller than the first traction force.

[0049] [Control unit] The control unit 4 is a variable cable length mechanism that changes the difference in cable length between the left control cable 21L and the right control cable 21R. By changing the cable length difference, the flying object 20 can be made to fly in an eight-shaped trajectory in the air. More specifically, by changing the cable length difference, the control unit 4 can force the flying object 20 to oscillate in an eight-shaped trajectory in the air or trigger self-excited oscillation. The control unit 4 has a left winch (not shown) that winds and unwinds the left control cable 21L and a right winch (not shown) that winds and unwinds the right control cable 21R. The power generation system 1 has a battery (not shown) that serves as a power source for driving the control unit 4. The battery is installed on the ground.

[0050] The control unit 4 that changes the cable length difference may be a system such as that described in Japanese Patent Application Laid-Open No. 2013-527893. In the control unit 4, the left control cable 21L, which extends between the left winch and the flying object 20, is bent midway at the left fulcrum. This bent portion is referred to as the first bent portion, and the cable length from the first bent portion to the flying object 20 is referred to as the "length of the left control cable." The right control cable 21R, which extends between the right winch and the flying object 20, is bent midway at the right fulcrum. This bent portion is referred to as the second bent portion, and the cable length from the second bent portion to the flying object 20 is referred to as the "length of the right control cable." The difference between the "length of the left control cable" and the "length of the right control cable" is referred to as the "cable length difference." The midpoint of the line segment connecting the left fulcrum and the right fulcrum is referred to as the "fulcrum O1 of the control cable." The control unit 4 is configured to be able to control the difference in cable length while the length of the cable from the winch to the flying object 20 is fixed. In the system described in JP 2013-527893 A, the turn-back blocks (reference numerals 4a and 4b) correspond to the left and right fulcrums, and the portions of the cable (corresponding to the "cable" in this specification) that contact these fulcrums and are bent correspond to the bent portions. In JP 2013-527893 A, the sliders (reference numerals 2a and 2b), turn-back blocks (reference numerals 4a and 4b), and motor (reference numeral 3) correspond to the "control unit" in this specification. In the system described in JP 2013-527893 A, the difference in cable length is controlled by moving the sliders using the driving motors.

[0051] When the control unit 4 is used to make the right control rope 21R longer than the left control rope 21L while the kite 2 is in the air, the flying object 20 will sway so as to tilt to the left. On the other hand, when the control unit 4 is used to make the left control rope 21L longer than the right control rope 21R, the flying object 20 will sway so as to tilt to the right. By alternately controlling the kite 2 to tilt to the left and to tilt to the right using the control unit 4, the flying object 20 can be intentionally adjusted to trace an eight-shaped trajectory. By adjusting the flying object 20 to trace an eight-shaped trajectory, a high pulling force can be generated on the kite 2 in the downwind and upward directions.

[0052] 8(A) will be used to explain a method of controlling a kite when adjusting the amplitude 11 of the horizontal figure-eight trajectory 10 of the flying object 20. When the flying object 20, which is tracing a figure-eight trajectory, reaches a predetermined position on the trajectory, the control unit 4 controls the left-right tilt of the kite 2, thereby changing (amplifying or attenuating) the amplitude 11 of the figure-eight trajectory 10.

[0053] As shown in FIG. 8(A), when flying object 20 traces a trajectory that descends obliquely in the center of figure-eight trajectory 10, to amplify amplitude 11, when flying object 20 is located near position M on figure-eight trajectory 10 where the upward transition occurs in left loop 10L on the figure and the downward transition occurs, control unit 4 controls the cable length difference so that flying object 20 tilts to the right. Furthermore, when flying object 20 is located near position N on figure-eight trajectory 10 where the upward transition occurs in right loop 10R on the figure and the downward transition occurs, control unit 4 controls the cable length difference so that flying object 20 tilts to the left. By alternately performing this process on the left and right, amplitude 11 of flying object 20 can be amplified. By increasing the amplitude 11 of the figure-eight trajectory 10, a difference in tension occurs between the left control rope 21L and the right control rope 21R, and when the tension exceeds a certain level, the flying object 20 begins to trace a horizontal figure-eight trajectory 10 by self-excited vibration without actively controlling the difference in rope length using the control unit 4.

[0054] On the other hand, when the amplitude 11 is to be attenuated, the cable length difference is controlled by the control unit 4 so that the flying object 20 tilts leftward when the flying object 20 is located near position M on the figure-8 trajectory 10 where the left loop 10L in the figure changes from rising to descending. Furthermore, when the flying object 20 is located near position N on the figure-8 trajectory 10 where the right loop 10R in the figure changes from rising to descending, the cable length difference is controlled by the control unit 4 so that the flying object 20 tilts rightward. By alternately performing this process on the left and right, the amplitude 11 of the flying object 20 can be attenuated.

[0055] The active variable control of the difference in cable lengths by the control unit 4 may be performed manually, or may be performed automatically based on image information obtained by a camera capturing an image of the trajectory of the flying object 20. For example, when the amplitude 11 of the figure-eight trajectory 10 of the flying object 20 is to be amplified, the control unit 4 controls the kite 2 by moving the slider so that the flying object 20 tilts to the right when the flying object 20 is located near position M (see FIG. 8(A)) based on the image information, and by moving the slider so that the flying object 20 tilts to the left when the flying object 20 is located near position N (see FIG. 8(A)).

[0056] Here, an example has been given in which the control unit 4 triggers the flying object 20 to self-excitedly oscillate in the figure-eight trajectory 10, and in the power generation mode, the control by the control unit 4 is stopped and the flying object 20 is self-excitedly oscillated in the figure-eight trajectory, but the control by the control unit 4 may be continued to forcibly oscillate the flying object 20 in the figure-eight trajectory 10. However, from the viewpoint of improving energy efficiency, it is preferable to stop the active control by the control unit 4 when the flying object 20 begins to continue to describe the horizontal figure-eight trajectory by self-excited oscillation without active cable length difference variable control. This makes it possible to reduce the energy consumed by the control unit 4, and as a result, improve the energy efficiency of the entire system.

[0057] In this embodiment, even without active variable control of the cable length difference using the control unit 4, when the flying object 20 begins to continue drawing a horizontal figure-eight trajectory due to self-excited vibration, the control by the control unit 4 is stopped and then power generation is switched to using the self-excited vibration of the flying object 20 in the figure-eight trajectory by the power generation unit 5. In other words, the control unit 4 basically operates only in kite control mode.

[0058] [Generator] The generator 52 converts mechanical energy supplied from the energy supply unit 3 into electric power (electrical energy). The generator 52 is, for example, a motor having a rotor with a magnet and a stator around which a coil is wound. A wheel shaft 79 that constitutes a part of the energy supply unit 3 is connected to the generator 52.

[0059] [Energy Generation Unit] As shown in FIGS. 1(A) and 3, the energy generating unit 30 is connected to the flying object 20 via the power rope 23. The energy generating unit 30 generates energy to be supplied to the generator 52 by utilizing the force (sometimes referred to as "traction force" or "tension") acting on the power rope 23 due to the flight of the kite 2. In the power generating system 1, the energy generating unit 30 is disposed on the control unit 4 so that the fulcrum O2 of the power rope 23 is located above and upwind of the fulcrum O1 of the control rope 21. This is the same in the second and third embodiments described below. The positional relationship between the fulcrum O1 and the fulcrum O2 will be described later.

[0060] As shown in FIGS. 2 to 4, the energy generating unit 30 includes a reel 60 as a movable body and a spring motor 73 having a helical spring (constant force spring) 53 as a spring mechanism serving as a restoring force mechanism. Furthermore, from the viewpoint of efficiently utilizing the energy of the reciprocating motion of the reel 60 in the rotational direction, the energy generating unit 30 preferably includes a first transmission mechanism 81, a second transmission mechanism 82, and a flywheel 63 as an energy storage mechanism, as in this embodiment. The energy generating unit 30 is preferably configured such that the restoring force of the helical spring 53 acts on the reel 60 in the power generation mode, but does not act on the reel 60 in the kite control mode, as in this embodiment. Below, the main components of the energy generating unit 30 are described, along with a description of the peripheral components.

[0061] (Reel (moving body)) As shown in FIGS. 3 and 4, the power cable 23 is wound around and supported by a reel 60 serving as a movable body. As shown in FIGS. 4B and 4C, the reel 60 is configured to reciprocate in a power generation mode by alternately changing direction between a first direction D1 and a second direction D2 opposite to the first direction D1, depending on the magnitude of the pulling force received from the kite 2, which is flying in a figure-eight trajectory to which the power cable 23 is connected. As shown in FIG. 4B, the reel 60 moves in the first direction D1 to unwind the power cable 23, and as shown in FIG. 4C, moves in the second direction D2 to reel in the power cable 23. In this embodiment, when the energy generating unit 30 is viewed from the flying object 20, the first direction D1 is the direction of rotation toward the depth, and the second direction D2 is the direction of rotation toward the front.

[0062] As shown in Figures 3 and 4(A) to (C), a reel shaft (through shaft) 74 is inserted into the reel 60. The reel 60, spring motor 73, gear 85 having a bearing therein, gear 83 of first transmission mechanism 81, and gear 84 of second transmission mechanism 82 are attached to the reel shaft 74, and the reel 60, spring motor 73, gear 83, and gear 84 are configured to be rotatable around the reel shaft 74 as the rotation axis.

[0063] 3, a pulley 56 that supports the power rope 23 is provided between the reel 60 and the flying object 20. The length of the power rope 23 from the fulcrum O2 to the branch point 233 changes according to the movement of the flying object 20 flying in an eight-shaped trajectory.

[0064] One end of the power rope 23 is indirectly connected to the flying object 20 via the control rope 21, and the other end is wound around and supported by the reel 60, so that the reel 60 and the reel shaft 74 receive a pulling force from the kite 2 flying due to the wind W and rotate.

[0065] A thread 741 is threaded on a portion of the surface of the reel shaft 74, and a nut 742 is attached to the thread 741. The nut 742 rotates relative to the reel shaft 74, allowing the nut 742 to move linearly along the threaded axis (reel shaft). A through-hole into which a phase-setting pin 77 is inserted is provided in the flange of the nut 742. The nut 742 and gear 85 are connected by a phase-setting pin 77, matching their rotational phases. With the pin 77 inserted in the through-hole, the nut 742 is able to move linearly along the reel shaft. On the other hand, the gear 85 cannot move along the reel shaft, and its position along the reel shaft is fixed. The nut 742 rotates in conjunction with the rotation of the gear 85. When the nut 742 moves closer to the reel 60, its movement is restricted by the presence of the gear 85. With this configuration, the positions of the spring motor 73 and the gear 85 can be adjusted and installed so that the number of turns of the wound spring is the number that is recommended in advance for obtaining stable torque when using the spring motor 73.

[0066] The energy generating unit 30 also includes a gear 87 that meshes with the gear 85, a gear 86 that meshes with the gear 87, and a winding motor 66 connected to the rotation shaft of the gear 86. The winding motor 66 powers the reel 60 in kite control mode. On the other hand, in power generation mode, the winding motor 66 is stopped by an electromagnetic brake (not shown). This disconnects the motor 66, which is required to change the overall length of the power cable 23, enabling steady power generation.

[0067] 2 and 3, the energy generating unit 30 also includes a reeling on / off lever 70 that limits the movement of the nut 742. In kite control mode, the reeling on / off lever 70 is set to on, limiting the movement of the nut 742 away from the reel along the reel axis, while in power generation mode, the reeling on / off lever 70 is set to off.

[0068] (Spring motor (return mechanism)) As shown in FIG. 3 , the spring motor 73 includes a coil spring (constant-force coil spring) 53, a shaft (not shown), and a case 731 that covers the coil spring 53. The coil spring 53 has a spiral shape formed by winding a highly elastic plate material in the plane direction, with one end connected to and wound around the shaft and the other end connected to the case 731. The shaft of the spring motor 73 is connected to a reel shaft 74 and rotates in conjunction with the rotation of the reel shaft 74. The restoring force of the coil spring 53 is smaller than the first tractive force but larger than the second tractive force. When a second tractive force smaller than the first tractive force acts on the reel 60, the coil spring 53 applies a restoring force to the reel 60 that rotates in the second direction D2. The coil spring motor 73 is also connected to a gear 85 and rotates in conjunction with the rotation of the gear 85.

[0069] In kite control mode, the spring motor 73 rotates as a whole, including the case 731, in conjunction with the rotation of the connected gear 85, and the restoring force of the wound spring 53 is not exerted. With this configuration, the overall length of the power rope 23 can be changed in kite control mode.

[0070] In the power generation mode, the power cable 23 is pulled out from the reel 60 by the first traction force generated when the flying object descends in the figure-eight trajectory, causing the reel 60 and the reel shaft 74 to rotate in the first direction D1, and the length of the power cable 23 becomes relatively longer. At this time, the winding spring 53 of the mainspring motor 73 connected to the reel shaft 74 is wound up. On the other hand, when a second tractive force smaller than the first tractive force, which is generated when the flying object ascends on the figure-eight trajectory, acts on the reel 60 and the reel shaft 74, the winding of the coil spring 53 of the mainspring motor 73 is released, generating a restoring force. The restoring force of the coil spring 53 causes the reel 60 to rotate in the second direction D2, and the power cable 23 is wound onto the reel 60, thereby relatively shortening the length of the power cable 23. In this way, the load of the coil spring 53 (the return force (restoring force) generated when stretched linearly) is set so that the restoring force of the coil spring 53 causes the reel 60 to rotate in the second direction D2 when the second tractive force acts. For example, the load of the coil spring 53 can be set to 6 N.

[0071] As in this embodiment, it is preferable to use a spring mechanism, which is a biasing mechanism, as the restoring mechanism. Because a spring mechanism can store a large amount of energy in a relatively small space, it is possible to reduce the size of the entire energy supply unit, and therefore the entire power generation system 1. In the second and third embodiments described below, a spring mechanism is also used as the restoring mechanism, and similarly, it is possible to reduce the size of the entire energy supply unit and the entire power generation system.

[0072] (Flywheel (energy storage mechanism)) The flywheel 63 as a mechanical energy storage mechanism can suppress fluctuations in the rotational speed of the rotational motion transmitted from the first transmission mechanism 81 and the second transmission mechanism 82 and can retain energy. This allows energy to be stably supplied to the generator 52. In addition, adding a transmission function to the flywheel makes it possible to change the load on the generator.

[0073] (First transmission mechanism and second transmission mechanism) The first transmission mechanism 81 and the second transmission mechanism 82 convert the reciprocating motion of the reel 60, which alternates between motion in the first direction D1 and motion in the second direction D2, into kinetic energy in the same direction. The first transmission mechanism 81 and the second transmission mechanism 82 align the rotary reciprocating motion of the reel 60 to motion in one rotational direction (rotational motion in the first direction in this embodiment). The first transmission mechanism 81 and the second transmission mechanism 82 are connected to the wheel shaft 79. The wheel shaft 79 and the flywheel 63 connected thereto rotate only in the aligned fixed rotational direction, and the energy generating unit 30 continuously generates energy in the same direction at all times.

[0074] 3, the first transmission mechanism 81 has a gear 71, a CCW one-way clutch 61 disposed therein, and a gear 83 that meshes with the gear 71. The CCW one-way clutch 61 is configured to rotate freely relative to the wheel shaft 79 in the second direction D2, and to engage with the wheel shaft 79 in the first direction D1.

[0075] The second transmission mechanism 82 has a gear 72, a CW one-way clutch 62 arranged therein, an idler gear 68 that meshes with the gear 72, and a gear 84 that meshes with the idler gear 68. The CW one-way clutch 62 is configured to rotate freely relative to the wheel shaft 79 in the first direction D1 and to engage with the wheel shaft 79 in the second direction D2.

[0076] The gear 71 having the CCW one-way clutch 61 therein of the first transmission mechanism 81, the gear 72 having the CW one-way clutch 62 therein of the second transmission mechanism 82, the flywheel 63, and the clutch 64 are attached to a wheel shaft 79. The gear 83 of the first transmission mechanism 81 and the gear 84 of the second transmission mechanism 82 are attached to a reel shaft 74.

[0077] The first transmission mechanism 81 converts the rotation of the reel 60 in the second direction D2 (reverse (CCW)) into rotation in the first direction D1 and transmits it to the wheel shaft 79. As shown in FIG. 4(C), when rotational motion in the second direction D2 occurs in the reel 60, the gear 83 rotates in the second direction D2, the gear 71 meshing with the gear 83 rotates in the first direction D1, and the wheel shaft 79 rotates in the first direction D1. The rotational motion (mechanical energy) of the wheel shaft 79 is supplied to the generator 52.

[0078] The second transmission mechanism 82 transmits the rotation of the reel 60 in the first direction D1 (forward rotation (CW)) to the wheel shaft 79. As shown in FIG. 4(B), when rotational motion in the first direction D1 occurs in the reel 60, the gear 84 rotates in the first direction D1, the idler gear 68 meshing with the gear 84 rotates in the second direction D2, and further, the gear 72 meshing with the idler gear 68 rotates in the first direction D1, and the wheel shaft 79 rotates in the first direction D1. The rotational motion (mechanical energy) of the wheel shaft 79 is supplied to the generator 52.

[0079] In this way, in the energy supply unit 3, the first transmission mechanism 81 and the second transmission mechanism 82, which utilize one-way clutches, can convert the reciprocating motion of the reel 60, which alternates between motion in the first direction D1 and motion in the second direction D2, into a single direction (the first direction D1 in this embodiment) and transmit it to the wheel shaft 79. This allows energy to be supplied to the generator 52 in the same direction at all times, enabling continuous power generation and excellent power generation efficiency. Furthermore, the use of the flywheel 63 allows a stable supply of mechanical energy to the generator 52.

[0080] From the viewpoint of stable and continuous power generation, it is preferable to provide a transmission mechanism using a one-way clutch so that energy is always obtained in the same direction, and further to use a flywheel 63, as in this embodiment.

[0081] The energy generating unit 30 also has a clutch 64 as a power transmission / disconnection mechanism. The clutch 64 controls the energy generated based on the reciprocating rotation of the reel 60 so that it is transmitted to the generator 52 in the power generation mode, and so that it is not transmitted (disconnected) to the generator 52 in the kite control mode. In this way, by preventing energy supply to the generator 52 until power generation using the kite's figure-eight flight trajectory is possible, it is possible to supply energy to the generator 52 at a stable rate.

[0082] <<Operation of the control unit and energy supply unit in each mode>> In FIG. 2, arrows between components in the energy supply unit 3 through which energy is transferred in kite control mode are indicated by dashed and hollow arrows, while arrows between components through which energy is transferred in power generation mode are indicated by solid and hollow arrows. In other words, hollow arrows indicate locations where energy transfer occurs in both kite control mode and power generation mode. As shown in FIG. 2, in the energy supply unit 3, a clutch 64 is controlled so that mechanical energy based on the reciprocating rotation of the reel 60 is supplied to the generator 52 in power generation mode, and so that transmission of the mechanical energy to the generator 52 is interrupted in kite control mode. Also, in kite control mode, the winding motor 66 is controlled to transmit power to the reel 60 without generating a restoring force in the winding spring 53. Also, in power generation mode, the winding motor 66 is stopped and the winding spring 53 is controlled to generate a restoring force. This will be explained in detail below.

[0083] [Kite control mode at takeoff (line length control mode)] (Control unit operation) First, the position of the power generation system 1 is determined so that the control unit 4 and the power generation unit 5 are on the windward side and the flying object 20 is on the leeward side. Next, the control unit 4 controls the movement of the kite at takeoff as follows (kite control mode).

[0084] The kite 2 can be taken off by extending the length of the control line, or by being transported into the sky by another flying object and released. Here, we will show an example in which the kite is taken off by extending the length of the control line 21. Also, the power line 23 is pulled out in advance, leaving a certain length of power line 23.

[0085] This section explains takeoff when there is no wind near the ground. By winding both the left control cable 21L and the right control cable 21R equally with the right and left winches until the cable lengths reach a predetermined length, the flying object 20 receives the wind and ascends. By rapidly winding the control cable 21 from a stretched state, the flying object 20 gains airspeed, enabling takeoff. After that, as the flying object 20 reaches a certain altitude, the wind force increases and the flying object 20 ascends without winding the control cable 23. At this time, the control cable 23 is reeled out. Once the cable length of the control cable 21 reaches a predetermined length, the use of each winch is stopped, and winding and unwinding by each winch are no longer performed. In other words, the length of the control cable 21 from each winch to the flying object 20 is fixed. Then, by controlling the cable length difference using the control unit 4, the flying object 20 is tilted alternately left and right, adjusting the attitude of the flying object 20 so that it traces an eight-shaped trajectory. Then, as described above with reference to FIG. 8 , the control unit 4 controls the cable length difference so that the amplitude 11 of the flying object 20 is amplified. In other words, when flying object 20, which is tracing a figure-eight trajectory 10, reaches a predetermined position on the figure-eight trajectory 10, the control unit 4 controls the cable length difference so that flying object 20 tilts in the direction opposite to the predetermined position (right or left). By repeating this process on the left and right sides, the amplitude 11 of flying object 20 is amplified. A difference in tension occurs between left control cable 21L and right control cable 21R, and the amplitude 11 of flying object 20 is amplified until the tension in control cable 21 reaches a certain level or higher. Then, when flying object 20 begins to continue tracing a horizontal figure-eight trajectory by self-excited vibration without active variable cable length control using control unit 4, control by control unit 4 is stopped and the mode is switched from kite control mode to power generation mode.

[0086] On the other hand, if there is wind near the ground, the aircraft will be able to take off even with the control line wound in. In this case, the control line is simply extended and stopped when it reaches the specified length.

[0087] Here, we have explained the control rope when the kite 2 takes off, but the kite 2 can land by reeling in the control rope, or by capturing the kite 2 in the air with another flying object and bringing it to the ground.

[0088] (Energy supply unit operation) The operation of the energy supply unit 3 in the kite control mode at takeoff will now be described with reference to FIGS. 2, 3 and 4(A).

[0089] In the kite control mode, power is transmitted from the reel winding motor 66 to the reel 60. The power of the reel winding motor 66 is transmitted to the gear 85 by the gear 86 and the gear 87, and as shown in FIG. 4(A), when the gear 85 rotates in the first direction D1, the entire mainspring motor 73, which is connected and fixed to the gear 85, also rotates. When the entire mainspring motor 73 rotates in this manner, the restoring force of the winding spring 53 of the mainspring motor 73 is not generated.

[0090] Furthermore, in kite control mode, the reeling on / off lever 70 is in the ON state, restricting the position of the nut 742. As the gear 85 rotates due to the drive of the reel winding motor 66, the nut 742 connected to the gear 85 also rotates, and the nut 742 moves along the reel axial direction. The reel shaft 74 does not rotate until the nut 742 rotates in the second direction D2 and its movement away from the reel 60 is restricted by the ON reel winding on / off lever 70. When the nut 742 further rotates in the second direction D2 and collides with the ON reel winding on / off lever 70, restricting its movement toward the reel 60, the reel shaft 74 and the reel 60 rotate in the second direction D2 due to the power of the reel winding motor 66. This causes the power cable 23 to be reeled.

[0091] Rotation of the reel shaft 74 also rotates the gear 83 of the first transmission mechanism 81 and the gear 84 of the second transmission mechanism 82, but in kite control mode, the clutch 64 blocks the rotational kinetic energy of the reel shaft 74 from being transmitted to the generator 52.

[0092] While the control unit 4 extends the length of the control rope 21, the energy supply unit 3 rotates the reel 60 in the second direction D2 to wind up the power rope 23, thereby adjusting the length of the power rope 23.

[0093] Here, we have explained the power rope 23 when the kite 2 takes off, but when the kite 2 lands, the power rope can be reeled in using the same method as when it takes off, or the kite 2 can be captured in the air by another flying object and brought to the ground.

[0094] [Power generation mode] (Operation of the power generating unit) In the power generation mode, the reel winding motor 66 is stopped by an electromagnetic brake (not shown). As a result, the gear 85, the nut 742 connected to the gear 85, and the spring motor 73 connected to the gear 85 do not rotate. This causes the restoring force of the winding spring 53 of the spring motor 73 to be generated. In addition, in the kite control mode, the winding on / off lever 70 is in the OFF state.

[0095] In the power generation mode, the traction force of the power cable 23 is changed by the kite 2 on the figure-eight trajectory. When the flying body 20 descends in a figure-eight trajectory, the first pulling force of the kite 2 pulls out the power cable 23 from the reel 60, causing the reel 60 and the reel shaft 74 to rotate in the first direction D1. The length of the power cable 23 becomes relatively long. When the flying body 20 ascends in a figure-eight trajectory, the reel 60 and the reel shaft 74 rotate in the second direction D2 due to the second tractive force (smaller than the first tractive force) of the kite 2 and the restoring force of the winding spring 53. The power cable 23 is wound around the reel 60, and the cable length becomes relatively short. As the pulling force of the kite 2 on the figure-eight trajectory changes, the reel 60 rotates alternately in the first direction D1 and the second direction D2 as described above, causing the reel 60 to rotate back and forth, and the mechanical energy based on this rotational reciprocating motion is supplied to the generator 52, generating electricity.

[0096] The detailed operation within the energy generating unit 30 when the flying object 20 ascends and descends on the figure-eight trajectory will be described below.

[0097] As shown in FIG. 4(B), when the flying object 20 descends in a figure-eight trajectory, the power cable 23 is pulled out by the first traction force, causing the reel 60 and the reel shaft 74 to rotate in the first direction D1. The energy of the rotational motion of the reel 60 in the first direction D1 is transmitted to the wheel shaft 79 by the second transmission mechanism 82 as rotational motion energy in the first direction D1, and this energy is supplied to the generator 52, generating electricity. Furthermore, the rotation of the reel shaft 74 causes the wound spring 53 of the mainspring motor 73 to be tightly wound so that the pitch between the plates becomes narrower. Furthermore, the rotation of the reel shaft 74 causes the nut 742 to move away from the reel 60 along the reel shaft direction.

[0098] When a second traction force smaller than the restoring force of the helical spring 53 acts on the helical spring 53, which has been wound up by the first traction force, a force that releases the winding (a restoring force that tries to return to its original state) is generated in the helical spring 53. As shown in FIG. 4(C), when the flying object 20 rises in the figure-eight trajectory, the second traction force and the restoring force of the helical spring 53 cause the reel shaft 74 and the reel 60 to rotate in the second direction D2, and the power cable 23 is wound up. The energy of the rotational motion of the reel 60 in the second direction D2 is converted by the first transmission mechanism 81 into energy of rotational motion in the first direction D1 and transmitted to the wheel shaft 79, and the energy is supplied to the generator 52, generating electricity. Furthermore, due to the rotation of the reel shaft 74, the nut 742 moves in the direction of the reel axis toward the reel 60.

[0099] In this way, the first transmission mechanism 81 and the second transmission mechanism 82 can cause the wheel shaft 79 to always rotate in the same rotation direction.

[0100] As shown in FIG. 8(A), in the figure-8 trajectory 10, near the descent point a where the flying object 20 descends from the left loop 10L to the right loop 10R, the reel 60 rotates in the first direction D1 using the first traction force. Subsequently, near the ascent point b where the flying object 20 of the right loop 10R ascends, the reel 60 rotates in the second direction D2 using the second traction force and the restoring force of the coil spring 53. Subsequently, near the descent point c where the flying object 20 descends from the right loop 10R to the left loop 10L, the reel 60 rotates in the first direction D1 using the first traction force. Subsequently, near the ascent point d where the flying object 20 of the left loop 10L ascends, the reel 60 rotates in the second direction D2 using the second traction force and the restoring force of the coil spring 53. In this way, while the flying object 20 makes one revolution in the figure-eight trajectory (one cycle), the reel 60 makes two reciprocating movements in the rotation direction.

[0101] In this way, in the power generation method of the power generation system 1 of this embodiment, when the flying object 20 descends on an eight-shaped trajectory, the tension acting on the power rope 23 increases, making the traction force (first traction force) relatively large, and when the flying object 20 ascends, the tension acting on the power rope 23 decreases, making the traction force (second traction force) relatively small.By further providing a coil spring (restoring force mechanism) 53, the rotary reciprocating motion of the reel 60 is realized.

[0102] <<Action and Effect>> In the energy supply unit of this embodiment, the pulling force of the kite and the restoring force of the restoring force mechanism are used to reciprocate the movable body (the reel in this embodiment), and the energy of this reciprocating motion is supplied to the generator. With this configuration, the range of motion of the movable body can be significantly reduced compared to conventional methods of towing a vehicle, and the safety area in case of a kite falling can be reduced.

[0103] Furthermore, in the energy supply unit of this embodiment, a separate cable (power cable) is used to control the kite (control cable), and the tension of the kite on its figure-eight trajectory is used to obtain the reciprocating motion of the movable body. This configuration makes it easy to adjust the positional relationship between fulcrum O1 and fulcrum O2 so that the direction of change in force in the power cable corresponds to the change in cable length, and fulcrum O1 and fulcrum O2 can be set to positions more suitable for energy generation using self-excited vibration. Furthermore, even if the power cable (or control cable) breaks, the other cable remains, preventing the kite from protruding outside the safety zone and causing damage such as falling.

[0104] Furthermore, in the power generation system 1 of this embodiment, the generator and the energy supply unit that supplies energy to the generator can be configured separately. Therefore, any existing generator can be attached to the energy supply unit to configure the power generation system. For example, a user can select a generator with the desired output depending on the application and attach it to the energy supply unit 3, making the energy supply unit 3 highly versatile. Furthermore, by changing the generator according to changes in wind power conditions due to the season, etc., it is possible to generate power under appropriate load conditions. Another advantage is that if either element fails, only the generator or the energy supply unit needs to be replaced.

[0105] Furthermore, because the energy supply unit of this embodiment does not utilize the kite's altitude change to generate power, there is almost no change in the cable length, making it possible to generate power under conditions with a longer cable length than the pumping cycle method. For example, in this embodiment, the kite can fly in an eight-shaped trajectory centered at an altitude of 300 m, and even if there is a change in altitude of several tens of meters, there is no change in altitude of 500 m, as in the pumping cycle, where the kite rises from an altitude of 300 m to 800 m. As a result, the safety area on the ground, taking into account the kite's fall, can be reduced.

[0106] Furthermore, in the pumping cycle system, the kite needs to be actively controlled to maintain its skidding flight, which consumes power. In contrast, the power generation system of this embodiment actively utilizes the self-oscillation mechanism during steady-state power generation, although flight maintenance control is required to cope with gusts of wind. This reduces the power required for active control of the kite.

[0107] Furthermore, in the power generation system of this embodiment, the trajectory of the flying object remains almost constant during steady-state power generation, and there is no need to make the flying object plummet as in the pumping cycle system, which reduces the risk of the flying object crashing.

[0108] In addition, the pumping cycle system occupies a large airspace due to the large altitude changes. In the power generation system of this embodiment, the flying object's trajectory remains almost constant during steady-state power generation, so the flying object's flight airspace is limited, making it possible to narrow the airspace available compared to the pumping cycle system. As a result, the safety area on the ground, taking into account the kite's fall, can be reduced.

[0109] In this embodiment, a spring mechanism (biasing mechanism) is used as the restoring force mechanism. The spring mechanism can store a large amount of energy in a relatively small space, and the overall size of the energy supply unit can be reduced.

[0110] The above-described effects can also be obtained in the second and third embodiments described below.

[0111] Furthermore, the energy generation unit of this embodiment uses a reel as the movable body, which is preferable because it is possible to save space compared to using a slider that moves on a rail as the movable body, as in the second and third embodiments described below, and it can also accommodate cases where the length of the power cable changes significantly during power generation mode.

[0112] As described above, power generation systems are highly safe, can alleviate restrictions on installation locations, reduce installation and removal costs, and are less likely to damage the landscape. For this reason, power generation systems are particularly effective in areas where installation locations are limited, such as near high-voltage power lines or coastlines close to residential areas, where the impact of a falling object must be considered. Furthermore, with a power generation system, the kite can be placed on the ground during bad weather, avoiding damage from wind, snow, and lightning strikes. Furthermore, power generation systems can be installed on the ground without mounting heavy objects such as the control unit and power generation unit on a flying vehicle, thereby reducing the safety zone and preventing the risk of heavy objects falling, thereby improving safety. In contrast, power generation systems that generate electricity by mounting a heavy motor on a flying vehicle and launching it into the air can reduce the safety zone, but the possibility of the motor falling reduces safety.

[0113] Second Embodiment 1(A) and 1(B), the power generation system 1A may be configured using a power generation unit 5A instead of the power generation unit 5. In the energy generation unit 30 of the first embodiment, a reel is used as the movable body, but in the energy generation unit 30A of this embodiment, a moving block 102 that moves back and forth linearly on a horizontal plane is used as the slider (movable body).

[0114] Fig. 5(A) is a block diagram showing the functional configuration of a power generation unit 5A according to the second embodiment, and Fig. 5(B) is a schematic diagram of the power generation unit 5A. Figs. 6(A) and 6(B) are perspective views of an energy generation unit 30A that constitutes a part of the power generation unit 5A.

[0115] Similar to the first embodiment, the power generation system 1A according to this embodiment generates electric power (generates electricity) by utilizing wind force received by the flying object 20 of the kite 2. As shown in FIG. 1, the power generation system 1A includes an energy supply unit 3A, a generator 52, and a control unit 4. As shown in FIGS. 1 and 5, the energy supply unit 3A includes the kite 2 and an energy generating unit 30A. The energy generating unit 30A and the generator 52 constitute a power generation unit 5A. Similar to the first embodiment, the energy supply unit 3A generates energy to be supplied to the generator 52. The generator 52 converts the energy into electricity to generate electricity. The first embodiment and the second embodiment differ in the configuration of the energy generating unit. The following mainly describes the configuration of the energy generating unit 30A.

[0116] Energy Generation Unit As shown in Figures 5(A) and (B) and Figures 6(A) and (B), the energy generating unit 30A includes a fixed block 101 having a pulley 105, a movable block 102 having a pulley 104 that serves as a movable pulley as a movable body, a constant force spring 53A as a restoring mechanism, a belt 51, a rail 54, a pulley 106 that is provided between the movable block 102 and the flying object 20 and supports the power rope 23, a reel 92 that winds and unwinds the power rope 23, a reel winding motor 96, and a pulley 103 that is provided between the movable block 102 and the reel 92 and supports the power rope 23.

[0117] [rail] As shown in Figures 5(B), 6(A) and (B), rails 54 extend parallel to the Y-axis direction, and moving block 102 is configured to be able to move back and forth linearly along the Y-axis direction on rails 54. Moving block 102 supports power cable 23 connected to flying body 20. As shown in Figure 5(B), the longitudinal direction of rails 54 and the direction of wind W are approximately perpendicular in top view.

[0118] [belt] 6(A) and 6(B), the moving block 102 is fixed to a belt 51 serving as a transmission mechanism. The belt 51 is an endless belt that is stretched around a rotating body 91 such as a gear. The belt 51 rotates in accordance with the linear reciprocating motion of the moving block 102, and the reciprocating rotational motion of the rotating body 91 around which the belt 51 is stretched is supplied to the generator 52 as mechanical energy.

[0119] [Fixed block, moving block] 6(A) and (B), the fixed block 101 has a multi-stage pulley structure including multiple pulleys 105, and its position is fixed. On the other hand, the movable block 102 functions as a slider (movable body). The movable block 102 has a multi-stage pulley structure including multiple pulleys 104 that function as movable pulleys, and is capable of linear reciprocating motion on the rail 54. The movable block 102 is a slider having a movable pulley mechanism.

[0120] As shown in FIGS. 6A and 6B, the power rope 23 is alternately placed over the pulley 105 of the fixed block 101 and the pulley 104 of the movable block 102 and wound in a figure-eight shape. The fixed block 101 and the movable block 102 support the power rope 23. The movable block 102 receives a traction force from the kite 2 flying in the wind W. The outer end 531 of the constant force spring 53A is connected to the movable block 102. The movable block 102 reciprocates in a first direction D1 and a second direction D2, which is the opposite direction to the first direction D1, by utilizing the traction force received from the kite 2 flying in the figure-eight trajectory and the restoring force of the constant force spring 53A. As the movable block 102 moves on the rail 54, the distance L between the fixed block 101 and the movable block 102 changes (see FIG. 5B).

[0121] In this embodiment, by adjusting the number of pulley stages of the fixed block 101 and the movable block 102, it is possible to adjust the tension of the kite 2 and the stroke of the movable block 102. In addition, by winding the power rope 23 around the fixed block 101 and the movable block 102 in an eight-shaped pattern, it is possible to prevent kinking, and the power rope 23 can be protected so that it is less likely to break.

[0122] 5(B), the power rope 23 is wound around a reel 92 so as to be able to be wound up and unwound. One end of the power rope 23 is connected to the flying object 20, and the other end is connected to the reel 92. The power rope 23 is supported by a fixed block 101 and a movable block 102 between the flying object 20 and the reel 92.

[0123] A pulley 103 supporting the power cable 23 is provided between the movable block 102 and the reel 92, and a pulley 106 supporting the power cable 23 is provided between the flying body 20 and the movable block 102. In power generation mode, the length of the power cable 23 from the reel 92 to the branch point 233 is constant. The length of the power cable 23 from the fulcrum O2 of the power cable 23, where the pulley 106 and the power cable 23 meet, to the branch point 233 changes according to the movement of the kite 2 on the figure-eight trajectory. This change in the length of the power cable 23 is absorbed by the movement of the movable block 10, which changes the distance L between the fixed block 101 and the movable block 102.

[0124] The moving block 102 receives a traction force from the kite 2 on the figure-eight trajectory. As with the power generation system 1 of the first embodiment, the power generation system 1A also utilizes the fact that when the flying object 20 descends on the figure-eight trajectory, the tension acting on the power rope 23 increases, making the traction force (first traction force) relatively large, and when the flying object 20 ascends, the tension acting on the power rope 23 decreases, making the traction force (second traction force) relatively small.

[0125] Specifically, when the flying object descends on the figure-8 trajectory, as shown in Fig. 6(A), the moving block 102 moves in the first direction D1 by utilizing the first tractive force generated during the descent, and the length of the power rope 23 from the fulcrum O2 to the branch point 233 becomes relatively long. On the other hand, when the flying object ascends on the figure-8 trajectory, as shown in Fig. 6(B), the moving block 102 moves in the second direction D2 by utilizing the second tractive force generated during the ascent and the restoring force of the constant force spring 53A described later, and the length of the power rope 23 from the fulcrum O2 to the branch point 233 becomes relatively short.

[0126] Constant force spring As shown in Figures 6(A) and 6(B), the energy generating unit 30A includes a constant force spring 53A as a restoring force mechanism. The constant force spring 53A is a spring made of a thin plate tightly wound with a constant curvature. An outer end 531 of the constant force spring 53A is connected to the moving block 102. The restoring force of the constant force spring 53A is smaller than the first traction force and larger than the second traction force.

[0127] When the kite 2 descends on the figure-eight trajectory, the moving block 102 is pulled by the power rope 23 with a first traction force, and moves in the first direction D1 so as to approach the fixed block 101, as shown in Fig. 6(A). The constant force spring 53A connected to the moving block 102 is pulled out and wound up.

[0128] On the other hand, during ascent, when a second traction force is generated in flight along a figure-eight trajectory in which the tension is lower than during descent, the constant force spring 53A is released from its tightening by a restoring force that is greater than the second traction force but smaller than the first traction force, and the moving block 102 moves in the second direction D2 away from the fixed block 101, as shown in Figure 6(B). In this way, when the second traction force that is smaller than the first traction force acts on the moving block 102 and the second traction force is smaller than the restoring force, the constant force spring 53A applies a force to the moving block 102 to move in the second direction D2.

[0129] [Reel, reel winding motor] As shown in Figure 5(B), the reel 92 is configured to be able to wind and unwind the power cable 23. In the kite control mode, the reel winding motor 96 controls the rotation of the reel 92 and controls the length of the wound power cable 23. On the other hand, in the power generation mode, the reel winding motor 96 is stopped.

[0130] Operation of the energy generating unit in power generation mode As shown in FIG. 8(A), in the figure-8 trajectory 10, near the descent point a where the flying object 20 descends from the left loop 10L to the right loop 10R, the moving block 102 moves in the first direction D1 using the first tractive force. Next, near the ascent point b where the flying object 20 ascends on the right loop 10R, the moving block 102 moves in the second direction D2 using the second tractive force and the restoring force of the constant force spring 53A. Next, near the descent point c where the flying object 20 descends from the right loop 10R to the left loop 10L, the moving block 102 moves in the first direction D1 using the first tractive force. Next, near the ascent point d where the flying object 20 ascends on the left loop 10L, the moving block 102 moves in the second direction D2 using the second tractive force and the restoring force of the constant force spring 53A. In this way, while the flying object 20 makes one revolution on the figure-eight orbit (one cycle), the moving block 102 makes two reciprocating movements in a linear direction. The movable body (movable block 102) moves back and forth, alternately moving in a first direction D1 and a second direction D2. In the energy generating unit 30A, the belt 54 to which the movable block 102 is fixed and the rotating body 91 rotate in conjunction with the reciprocating motion of the movable block 102, and energy supplied to the generator 52 is generated. A slider 55 as a movable body in a third embodiment described later also functions in the same manner as the moving block 102.

[0131] In this way, while the first embodiment employs a reel system, a slider system may be employed as in the energy supply unit 3A of this embodiment. From the viewpoint of increasing the change in the length of the power cable 23 to improve power generation efficiency while further reducing the size of the entire power generating device, it is preferable to employ the reel system as in the first embodiment, and by using the reel system, the change in the length of the power cable is not restricted by the dimensions of the rail.

[0132] In this embodiment, as in the first embodiment, the safety area can be reduced, the safety is high, restrictions on installation locations can be relaxed, costs for installation and removal can be reduced, and the power generation device is less likely to spoil the scenery.

[0133] <Third embodiment> 1(A) and 1(B), a power generation system 1B may be configured using a power generation unit 5B instead of the power generation unit 5. While the energy generation unit 30 of the first embodiment uses a rotating reel as the movable body, the energy generation unit 30B of this embodiment uses a slider 55 that moves back and forth linearly on a horizontal plane as the movable body.

[0134] FIG. 7(A) is a block diagram illustrating the functional configuration of a power generation unit 5B according to the third embodiment, FIG. 7(B) is a schematic side view of the power generation unit 5B, and FIG. 7(C) is a schematic top view of the power generation unit 5B. The energy generation unit 30B of the third embodiment uses a slider as the movable body, similar to the energy generation unit 30A of the second embodiment. The energy generation unit of the third embodiment is a simplified version of the energy generation unit of the second embodiment. As shown in FIG. 7(C), the longitudinal direction of the rail 54 (which coincides with the direction of the linear reciprocating motion of the slider) and the direction of the wind W are substantially parallel.

[0135] Similar to the first and second embodiments, the power generation system 1B according to this embodiment generates electric power (generates electricity) by utilizing wind force received by the flying object 20 of the kite 2. As shown in FIG. 1, the power generation system 1B includes an energy supply unit 3B, a generator 52, and a control unit 4. As shown in FIGS. 1 and 7(A), the energy supply unit 3B includes the kite 2 and an energy generating unit 30B. The energy generating unit 30B and the generator 52 constitute a power generation unit 5B. Similar to the first embodiment, the energy supply unit 3B generates mechanical energy to be supplied to the generator 52. The generator 52 converts the mechanical energy into electric power to generate electricity. The first and second embodiments differ from the third embodiment in the configuration of the energy generating unit. The following mainly describes the configuration of the energy generating unit 30B.

[0136] Energy Generation Unit As shown in FIGS. 7(A) to 7(C), the energy generating unit 30B has a slider 55 as a movable body, a constant force spring 53A as a restoring force mechanism, a belt 51 as a transmission mechanism, a rail 54, and a pulley 156.

[0137] As shown in FIG. 7B, the slider 55 moves linearly back and forth on a rail 54 extending linearly along the X-axis direction, alternately moving in a first direction D1 and a second direction D2. As in the second embodiment, the slider 55 as a movable body is fixed to a belt 51. The belt 51 rotates in accordance with the linear reciprocating motion of the slider 55, and the rotary reciprocating motion of the rotating body around which the belt 51 is stretched is supplied as energy to a generator 52. The generator 52 converts the energy into electricity and generates power. Also in this embodiment, as in the second embodiment, a constant force spring 53A is provided as a restoring mechanism, and its outer end 531 is connected to the slider 55. The linear reciprocating motion of the slider 55 is realized by utilizing the change in tension of the flying object 20 on the figure-eight trajectory and the restoring force of the constant force spring 53A. In this embodiment, too, the slider 55 makes two reciprocating motions while the flying object 20 makes one revolution on the figure-eight trajectory (one cycle).

[0138] In this way, while the first embodiment employs a reel system, a slider system may be employed as in the energy supply unit 3B of this embodiment. In this embodiment, as in the first and second embodiments, the safety area can be reduced, high safety is achieved, restrictions on installation locations can be alleviated, installation and removal costs can be reduced, and a power generation device that is less likely to spoil the scenery can be obtained.

[0139] <Positional relationship between fulcrum O1 and fulcrum O2>

[0140] In the first to third embodiments described above, from the viewpoint of good reciprocating motion of the movable body (reel 60, moving block 102, slider 55), it is preferable to adjust the length of the power rope 23 so that it is in a state of tension to a certain extent, and to adjust the positions of the fulcrum O2 of the power rope 23 and the fulcrum O1 of the control rope 21 so that the length of the power rope 23 is relatively long when the tension in the power rope 23 is strong and the length of the power rope 23 is relatively short when the tension in the power rope 23 is weak.

[0141] In the first to third embodiments, as shown in Fig. 1(B), the control unit 4 and the energy supply units 3, 3A, and 3B are arranged so that the fulcrum O2 of the power rope 23 is located above and on the upwind side of the fulcrum O1 of the control rope 21. By arranging the fulcrums in this positional relationship, it is possible to adjust the length of the power rope 23 so that it is relatively long when the tension in the power rope 23 is relatively strong, and so that it is relatively short when the tension in the power rope 23 is relatively weak. Below, an explanation will be given using Fig. 9, taking the energy supply unit 3B of the third embodiment as an example.

[0142] 9(A) and 9(B) are schematic diagrams showing the arrangement of the fulcrum O2 of the power cable 23 suitable for self-excited oscillation when the power generation system is viewed from above. Because the kite is uncontrolled during self-excited oscillation, the lengths of the two control cables 21 (right control cable 21R and left control cable 21L) do not change. Therefore, in a simplified two-dimensional state with no change in the elevation angle, the flying object 20 exists on a circular orbit with the fulcrum O1 as the origin. In the figures, the open circles labeled A and B indicate the position of the flying object 20. As shown in FIGS. 9(A) and 9(B), when the fulcrum O2 is positioned upwind of the fulcrum O1, reciprocating motion can be generated using the power cable 23 while maintaining the original self-excited oscillation. The reason for this is as follows.

[0143] As shown in Figures 9(A) and 9(B), in the above-described positional relationship, the distance between O2 and A is longer than the distance between O2 and B. Therefore, as shown in Figure 9(A), when the flying object moves from B to A, moving the slider 55 downwind matches the relationship between the flying object's circular orbit and the length of the power cable. The pulling force generated by the kite is high in the center of the figure-eight orbit and low at the left and right ends of the figure-eight orbit. Therefore, the pulling force at position A is higher than the pulling force at position B. Therefore, when the flying object moves from B to A, the slider 55 moves downwind due to the change in the pulling force of the flying object. In other words, the direction of movement of the slider 55 matches the direction of movement due to the relationship between the flying object's circular orbit and the length of the power cable, and no contradiction occurs. Furthermore, as shown in Figure 9(B), when the flying object moves from A to B, the pulling force of the kite decreases, and the slider 55 moves upwind due to the restoring force of the restoring mechanism (constant force spring). As a result, the excess power cable due to the difference in length between the O2-A distance and the O2-B distance is absorbed by the movement of the slider 55. As a result, with the above positional relationship, the reciprocating motion of the slider 55 and the trajectory of self-excited vibration are compatible.

[0144] If the power cable's fulcrum O2 were positioned downwind of the control cable's fulcrum O1, the kite's tension would change under the same conditions as in Figure 9, with the O2-A distance being shorter than the O2-B distance, reversing the relationship between the two distances. Therefore, as shown in Figure 9, it would be impossible to change the cable length to achieve the original self-excited oscillation trajectory. If self-excited oscillation were maintained, when the flying object moves from B to A, the slider 55 would move downwind, resulting in excess power cable, and when the flying object moves from A to B, the slider 55 would move upwind, resulting in insufficient power cable length. This means that the slider's reciprocating motion and the self-excited oscillation trajectory would no longer be compatible.

[0145] The power generation unit 5B using the energy supply unit 30B shown in the third embodiment and the control unit 4 were arranged in the above-mentioned positional relationship, and the flying object 20 was self-excited to oscillate in a figure-eight trajectory by the control unit 4. The experiment results are shown in Figure 10. In the experiment, the length of each of the right and left control cables was set to 5 m. The flying object 20 had a span length of 1346 mm and a wing area of ​​0.56 m. 2 The weight was 0.130 kg and the material was ripstop polyester. The wind speed during the experiment was 7.5 m / s.

[0146] Figure 10(A) shows the trajectories of the end points of the right control rope and the left control rope, and the trajectory of the midpoint of these end points. The end points of the control ropes are the connection points 213 of the main control rope 211 and the multiple small control rope threads 212 extending from the flying object 20, and the midpoint is the center point of the line connecting the connection points 213 of the two control ropes 21. In Figure 10(A), the area 14 with the sparsest dot density represents a change in the end point of the right control rope, the area 15 with the next sparsest dot density represents a change in the end point of the left control rope, and the area 16 with the densest dot density represents a change in the midpoint. Figure 10(B) shows the change in force at the midpoint, which was calculated from the actual measured values ​​of the forces of the right and left control cables. In Figure 10(B), the darker the color, the greater the force. Figure 10(C) is a graph showing the change in the length from the fulcrum O2 of the power rope to the midpoint. The fulcrum O2 of the power rope is located 300 mm upwind and 200 mm above the fulcrum O1 of the control rope. In Figure 10(C), the darker the color, the longer the length from the fulcrum O2 of the power rope to the midpoint. "The length from the fulcrum O2 of the power rope to the midpoint increases" means "the length of the power rope increases."

[0147] As shown in Figure 10(B), the midpoint follows an eight-shaped trajectory, with the force (tension) increasing when descending and decreasing when ascending. As shown in Figure 10(C), the power rope length increases when descending and decreases when ascending. By positioning the fulcrum O2 of the power rope 23 higher and upwind than the fulcrum O1 of the control rope 21, as shown in Figures 10(B) and 10(C), it is possible to adjust the length of the power rope so that it increases when the tension in the power rope increases and decreases when the tension in the power rope decreases, and it has been confirmed that the slider 55 can be reciprocated satisfactorily.

[0148] On the other hand, when the fulcrum O2 of the power rope 23 is positioned further downwind than the fulcrum O1 of the control rope 21, the length of the power rope becomes shorter when the tension of the power rope increases in the figure-eight trajectory, and the length of the power rope becomes longer when the tension decreases.

[0149] The position of the branch point 233 in the power rope 23 is not limited, but it is preferable that the length of the power rope small thread 232 is shorter, as this reduces the air resistance and weight of the rope.

[0150] <Modification> Although various embodiments of the present invention have been described above, these embodiments are merely examples, and the present invention is not limited to the specific embodiments disclosed herein. Furthermore, it goes without saying that the scope of the present invention is not limited to these embodiments.

[0151] Variation 1 In the power generation systems 1, 1A, and 1B of the above-described embodiments, as shown in the schematic diagram of FIG. 11(C), an example was given in which the control line 21 is connected to the control unit 4 and the control unit 4 controls the kite's flight along an eight-shaped trajectory. However, as shown in FIGS. 11(A) and 11(B), a person P may manipulate the control line 21 to adjust the flying object to fly along an eight-shaped trajectory. Note that while the drawings in FIGS. 11(A) and 11(B) are simplified, in detail, the control line 21 has a left control line and a right control line. The person P manipulates the left control line with his left hand and the right control line with his right hand to control the movement of the flying object 20.

[0152] 11(A) and 11(B), the control unit 4 is not required, and the overall power generation system can be made smaller. This makes it convenient to generate power using wind at any location. Furthermore, since a battery or other power source to drive the control unit 4 is not required and the energy generation unit can generate energy to supply to the generator 52 by using the kite's human-powered flight along a figure-eight trajectory, this is useful in times of disaster, etc. Furthermore, the energy supply unit of the present invention may be applied to sports or leisure activities in which participants compete to generate the most power by using the energy generation unit to fly a kite controlled by a human in a figure-eight trajectory.

[0153] When a human operates a kite, the parts of the control rope grasped by each hand by the human become the right and left fulcrums, and the midpoint of the imaginary line segment connecting the right and left fulcrums becomes fulcrum O1 of the control rope. Because a human can freely control the kite's movement, the kite can be flown with fulcrum O2 of power rope 23 positioned above and upwind of fulcrum O1, as shown in Figure 11(A), or with fulcrum O2 of power rope 23 positioned below and downwind of fulcrum O1, as shown in Figure 11(B). Furthermore, because the kite's movement can be controlled by the human, it is easy to verify the kite's trajectory, etc., that is more suitable for efficient energy generation.

[0154] In this specification, the power generation system includes an energy supply unit and other components (a control unit and / or a generator). For example, the power generation system may be composed of an energy supply unit and a generator, and the user may control the flight of the kite using the power generation system as in this modified example. Alternatively, the power generation system may be composed of an energy supply unit and a control unit, and an arbitrary generator may be attached by the user. Alternatively, the power generation system may be composed of an energy supply unit, a control unit, and a generator. Alternatively, the power generation system may be configured by attaching an arbitrary generator to the energy supply unit by the user.

[0155] Variation 2 In the above embodiment, an example in which the kite 2 has two control cables 21 has been given, but this is not limiting and there may be two or more control cables 21. In order to make the flying object 20 fly in an eight-shaped trajectory, there should be at least one cable connected to each of the left and right ends of the flying object 20 and connected to the control unit 4.

[0156] Variation 3 In each of the above-described embodiments, as shown in FIG. 8(A), the flying direction of the flying object 20 on the figure-eight trajectory 10 is set so that the flying object 20 descends in the center of the figure-eight trajectory 10 (near the area between the left loop 10L and the right loop 10R), but the flying object 20 may also ascend. [Explanation of symbols]

[0157] 1, 1A, 1B...Power generation system 2. Kite 3, 3A, 3B...Energy supply unit 4...Control unit 10...figure-eight orbit 20…flying object 21...Control cable 21L...Left side rope (first control rope) 21R...Right side rope (second control rope) 23...power cable 30, 30A, 30B...Energy generating units 52...Generator 53... Coil spring (restoring force mechanism) 53A...Constant force spring (restoring force mechanism) 54...Rail 55...Slider (movable body) 60...Reel (moving body) 81...First transmission mechanism 82...Second transmission mechanism 92...Reel 102...Moving block (slider, movable body) D1…first direction D2…Second direction O1…Control rope fulcrum O2: Power rope fulcrum

Claims

1. An energy supply unit for supplying energy to a generator, comprising: A kite having a flying body and a control line and a power line connected to the flying body, the flying body being configured to be able to fly in a figure-eight trajectory using the control line by utilizing wind power; a movable body supporting the power rope, the movable body being configured to be capable of reciprocating in a first direction and a second direction opposite to the first direction in response to the magnitude of the pulling force received from the kite flying in the figure-eight trajectory; a restoring force mechanism that applies a restoring force to the movable body that is smaller than a first tractive force received from the kite and larger than a second tractive force that is smaller than the first tractive force received from the kite; an energy generating unit comprising: an energy generating unit that generates the energy using the reciprocating motion of the movable body; An energy supply unit comprising:

2. 2. An energy supply unit according to claim 1, the first tractive force is a tractive force generated when the flying object descends on a figure-eight trajectory, and the second tractive force is a tractive force generated when the flying object ascends on a figure-eight trajectory, The restoring force mechanism applies the restoring force to the movable body when the second traction force acts on the movable body, which is moved in the first direction by the first traction force, thereby moving the movable body in the second direction. Energy supply unit.

3. 3. An energy supply unit according to claim 1 or 2, The restoring force mechanism is a spring mechanism. Energy supply unit.

4. 3. An energy supply unit according to claim 1 or 2, The energy generating unit further includes a transmission mechanism that converts one of the first and second directions of the movement of the movable body into energy of the other direction of movement and transmits the energy to the generator. Energy supply unit.

5. 3. An energy supply unit according to claim 1 or 2, The restoring force mechanism does not apply the restoring force to the movable body until the flying object takes an eight-shaped trajectory, and after the flying object takes an eight-shaped trajectory, applies the restoring force to the movable body when the flying object rises on the eight-shaped trajectory. Energy control mechanism.

6. 3. An energy supply unit according to claim 1 or 2, The flying object follows a figure-eight trajectory due to self-excited vibration. Energy supply unit.

7. 3. An energy supply unit according to claim 1 or 2, The movable body is a reel on which the power cable is wound, and rotates in the first direction to pull out the power cable and rotates in the second direction to wind up the power cable. Energy supply unit.

8. 3. An energy supply unit according to claim 1 or 2, The energy generating unit further includes a linear rail that guides the movement of the movable body, The movable body is a slider that moves linearly back and forth on the rail in the first direction and the second direction. Energy supply unit.

9. 3. An energy supply unit according to claim 1 or 2, the control line includes a first control line and a second control line each connected to the flying object; The flying object flies in an eight-shaped trajectory in the air by changing the cable length difference, which is the difference between the length of the first control cable and the length of the second control cable. Energy supply unit.

10. 3. An energy supply unit according to claim 1 or 2, The fulcrum of the power rope is located above and on the windward side of the fulcrum of the control rope. Energy supply unit.

11. An energy supply unit according to claim 1 or 2; a generator to which the energy is supplied from the energy supply unit; Equipped with Power generation system.

12. The power generation system according to claim 11, a control unit capable of causing the flying object to fly in a figure-eight trajectory in the air; The power line is connected to the energy generating unit, and the control line is connected to the control unit. Power generation system.

13. An energy supply unit according to claim 1 or 2; a control unit to which the control cable is connected and which can make the flying object fly in an eight-figure trajectory in the air; A power generation system comprising:

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