Power generation device

Abstract

To provide a power generation device capable of reducing a safety area with respect to the case of kite falling.SOLUTION: A power generation device comprises a support body, a kite, a movable body, and a power generator. The support body includes an inclined plane which becomes an upward inclination from a windward side to a leeward side. The kite includes: a flying body; and a first cord and a second cord which are connected to the flying body. The movable body is connected to the first cord and the second cord, includes a kite control unit which enables the flying body to fly in the air along a figure-of-eight shaped orbit by changing a cord length difference which is a difference between a length of the first cord and a length of the second cord, and can reciprocate in the inclined plane to the leeward side and the windward side in accordance with a magnitude of traction force received from the kite. The power generator includes a power generation mechanism installed on the ground and a connection part, which connects the power generation mechanism with the movable body, and converts the reciprocation of the movable body on the inclined plane into electric power.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a kite-based power generation device. [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, a flying object is flown in 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 it 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 type. In this type, when the kite catches the wind and rises, the rope is pulled out, and energy is extracted by rotating a drum around which the rope is wound. When the rope has been pulled out to a predetermined length, the kite is lowered. At this time, the kite is given a negative angle of attack, for example, to minimize drag and minimize the energy required to reel in the rope. As a result, the amount of energy generated when the rope is pulled out is greater than the amount of energy consumed when reeling it in, and a net energy can be generated in this one cycle (see Patent Documents 1 to 5).

[0004] Other methods for extracting energy with 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 motion of a kite is converted into the left and right movement of a lever (see Patent Document 7), and a method in which both ends of a vertical axis wind turbine are kites (see Patent Document 8).

[0005] Another method for extracting energy with a generator fixed on the ground is towing a vehicle with a generator on it with 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] Among the above-mentioned methods, the methods other than the pumping cycle method have not been put to practical use due to problems with structural stability and efficiency. For example, the wind turbine device described in Patent Document 6 has a structure that combines multiple ropes and flexible wings, so it has a structural stability problem in that it is weaker in dealing with gusts of wind than a normal kite used in the pumping cycle method. Also, the wind power generation system described in Patent Document 8 has a similar structural stability problem in the turbine part attached to the kite. In the wind energy recovery device described in Patent Document 7, in which the kite is reciprocated left and right in a roughly arc-shaped trajectory to drive the power lever and output power, the pulling force that theoretically contributes to energy generation is smaller than that of the pumping cycle method that utilizes the pulling force downward and upward, and is not efficient. For this reason, the pumping cycle method and the vehicle towing method described in Patent Document 9 and Patent Document 10 are practical methods. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2004-232461 A [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] JP 2020-94521 A [Patent Document 6] JP 2022-34899 A [Patent Document 7] International Publication No. 2013 / 094623 [Patent Document 8] JP 2014-51991 A [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, pp.1461-1476, 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 rope to be stretched to a certain length, so an area of ​​at least several hundred meters must be secured in consideration of the safety area against the falling of the flying object and the rope. In addition, the vehicle towing system requires rails for the vehicle to travel around, and further requires a safety area against the falling of the flying object and the rope.

[0010] In view of the above circumstances, an object of the present invention is to provide a power generating device capable of reducing the safety area in the event of a kite drop. [Means for solving the problem]

[0011] In order to achieve the above object, a power generating device according to one embodiment of the present invention includes a support, a kite, a movable body, and a generator. The support has an inclined surface that slopes upward from the windward side to the leeward side. The kite has a flying body, and a first rope and a second rope connected to the flying body. The movable body has a kite control unit connected to the first rope and the second rope, and capable of flying the flying body in an eight-shaped trajectory in the air by changing a rope length difference that is the difference between the length of the first rope and the length of the second rope, and is configured to be able to reciprocate on the inclined surface to the leeward side and the windward side depending on the magnitude of the pulling force received from the kite. The generator has a power generating mechanism installed on the ground and a connecting part that connects the power generating mechanism and the movable body, and converts the reciprocating motion of the movable body on the inclined surface into electric power.

[0012] With this configuration, the kite flying in an eight-shaped trajectory is used to reciprocate the movable body on the inclined surface, thereby making it possible to extract power efficiently and reduce the range of movement of the movable body, thereby reducing the necessary safety area in case the kite falls.

[0013] The kite control unit may alternately execute a first operation of causing the kite to pull the movable body toward the downwind side by utilizing the wind force received by the flying body, and a second operation of moving the movable body toward the upwind side by utilizing the own weight of the movable body.

[0014] The kite control unit may switch between the first operation and the second operation by changing an elevation angle of the kite.

[0015] The movable body may alternately move downwind using a first tractive force generated when the flying body descends on the figure-of-eight trajectory, and move upwind using a second tractive force smaller than the first tractive force and the movable body's own weight generated when the flying body ascends on the figure-of-eight trajectory.

[0016] The kite control unit may be configured to change the cable length difference to force the flying object to oscillate in an eight-shaped trajectory in the air, or to trigger the flying object to self-oscillate in an eight-shaped trajectory.

[0017] The support may further include a rotating table capable of changing the orientation of the inclined surface.

[0018] The inclined surface may have a guide rail for guiding the movement of the movable body.

[0019] The inclined surface may have a slope that increases in degree from the windward side to the leeward side.

[0020] The system may further include a biasing mechanism for biasing the movable body located on the leeward side to move in a direction from the leeward side to the upwind side, and / or a biasing mechanism for biasing the movable body located on the windward side to move in a direction from the upwind side to the leeward side. Effect of the Invention

[0021] According to the present invention, a power generating device can be provided that can reduce the safety area in case the kite falls, without hoisting heavy objects related to kite control and power generation into the air.

[0022] Note that the effects described herein are not necessarily limited to those described herein, and may be any of the effects described in this disclosure. [Brief description of the drawings]

[0023] [Figure 1] 1 is a schematic diagram of a power generating device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram for explaining power generation in the power generating device according to the first embodiment. [Diagram 3] (A) is a diagram explaining the figure-eight trajectory of a kite, and (B) is a schematic diagram showing the forces acting on the right and left ropes when the kite flies in the figure-eight trajectory. [Figure 4] FIG. 13 is a diagram illustrating a method of controlling a kite when adjusting the amplitude of the horizontal figure-of-eight trajectory of the flying object. [Diagram 5] This figure shows the changes in azimuth and elevation angles of the rope, changes in tension in the rope, and changes in the movement of the slide of the kite control unit when the movable body to which the kite is connected is pulled in a straight line by a towing vehicle at a constant speed and the flying object is made to fly by applying a simulated wind. [Figure 6] FIG. 11 is a diagram for explaining power generation in a power generating device according to a second embodiment. [Figure 7] FIG. 11 is a schematic diagram of a power generating device according to a third modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0025] First Embodiment

[0026] [Power generation equipment]

[0027] FIG. 1 is a schematic diagram of a power generating device 1 according to a first embodiment of the present invention. The power generating device 1 generates electric power (generates electricity) by utilizing wind force received by a flying body 20 of a kite 2. The power generating device 1 includes a kite 2, a movable body 4, a generator 5, and a support 6. The kite 2 includes a flying body 20 and a left rope 21L as a first rope and a right rope 21R as a second rope, which are connected to the flying body 20. The movable body 4 includes a kite control unit 40 and a battery 41 that serves as a power source for driving the kite control unit 40. The support 6 includes a base 63 installed on the ground G, a rotary table 64 provided on the base 63 so as to be rotatable about a vertical axis, and a platform 62 having an inclined surface 60 arranged on the rotary table 64. The inclined surface 60 has an upward inclination from the windward side 12 toward the leeward side 13. The movable body 4 is configured to be able to reciprocate on the inclined surface 60 to the leeward side 13 and the windward side 12 depending on the magnitude of the pulling force received from the kite 2. Specifically, in this embodiment, the inclined surface 60 has a guide rail 61 that guides the movement of the movable body 4, and the movable body 4 has a carriage 141 that slides on the guide rail 61, so that the movable body 4 is able to reciprocate on the guide rail 61 between the leeward side 13 and the windward side 12.

[0028] From the viewpoint of flying the flying object 20 on a horizontal figure-of-eight trajectory (hereinafter sometimes simply referred to as a "figure-of-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. In addition, it is preferable to use a flexible wing for the flying object 20.

[0029] One end of each of the left rope 21L and the right rope 21R is connected to the flying object 20, and the other end is connected to the movable object 4. In this embodiment, the number of ropes is two, but it may be two or more. When it is not necessary to distinguish between the left rope 21L and the right rope 21R, they are called ropes 21. When generating electric power using the power generating device 1, the length of the rope 21 can be about several tens of meters, for example, about 65 m. If the rope is too long, it may become entangled, and from the viewpoint of suppressing the occurrence of entanglement, it is preferable that the length of the rope is about several tens of meters. In contrast, in the pumping cycle method, the length of the rope is generally several hundred meters to about 1 km, and the power generating device 1 of the present invention can significantly reduce the range of the necessary safety area (hereinafter, sometimes simply referred to as the "safety area") in consideration of kite falling, compared to the pumping cycle method. Furthermore, under Japan's aviation law, the submission of a flight report is required for the launch of a flying object exceeding 150 m above land directly below an air route (250 m elsewhere); however, with power generation system 1, it is possible to set the altitude of flying object 20 at or below the 150 m stipulated by the aviation law, thereby relaxing restrictions on the location where power generation system 1 can be installed.

[0030] The base 62 is fixedly disposed on a rotating table 64. The rotating table 64 makes it possible to change the orientation of the inclined surface 60. By rotating the rotating table 64, the orientation of the inclined surface 60 can be adjusted so that it slopes upward from the windward side 12 to the leeward side 13. The inclination direction of the inclined surface 60 coincides with the average pulling direction of the rope 21.

[0031] The guide rail 61 and the carriage 141 constitute a linear guide 14, which is a guide mechanism for moving the movable body 4 on the inclined surface 60. The guide rail 61, which is a track for the movable body 4 to travel, is typically constituted by two parallel rails. The guide rail 61 extends parallel to the inclination direction between the windward side 12 and the leeward side 13 of the inclined surface 60. By arranging the inclined surface 60 of the support body 6 so that it is inclined upward from the windward side 12 to the leeward side 13, the movable body 4 can move on the guide rail 61 from the leeward side 13 to the windward side 12 by its own weight. Note that the guide mechanism only needs to guide the movable body 4 to reciprocate between the windward side 12 and the leeward side 13 on the inclined surface 60, and may be constituted by, for example, a guide rail and wheels in addition to a linear guide, and a commonly used one can be used. The total length of the inclined surface 60 having the guide rail 61 is not particularly limited, but can be a size of about several meters to 10 meters, and the safety area can be reduced.

[0032] The movable body 4 has a kite control unit 40, a battery 41, and a carriage 141 provided at the bottom of the movable body 4. The rope 21 of the kite 2 and a connecting part 52 of the generator 5 are connected to the movable body 4. The kite control unit 40 is a rope length difference variable mechanism that changes the length difference between the first rope of the left rope 21L and the second rope of the right rope 21R. By changing the rope length difference, it is possible to make the flying object 20 fly in an eight-shaped trajectory in the air. More specifically, the kite control unit 40 can change the rope length difference to forcibly oscillate the flying object 20 in an eight-shaped trajectory in the air or to trigger self-excited oscillation. The kite control unit 40 has a left winch (not shown) as a first winch that winds up and unwinds the left rope 21L, and a right winch (not shown) as a second winch that winds up and unwinds the right rope 21R. The battery 41 may be located outside the movable body 4 .

[0033] As the kite control unit 40 that changes the cable length difference, a system described in JP 2013-527893 A or the like can be used. In the kite control unit 40, the left cable 21L that is provided between the left winch and the flying object 20 is bent at a fulcrum (not shown). The bent portion is called the first bent portion, and the cable length from the first bent portion to the flying object 20 is called the "first cable length". The right cable 21R that is provided between the right winch and the flying object 20 is bent at a fulcrum (not shown). The bent portion is called the second bent portion, and the cable length from the second bent portion to the flying object 20 is called the "second cable length". In this specification, the "cable length difference" refers to the difference between the "first cable length" and the "second cable length". The kite control unit 40 is configured to be able to control the cable length difference 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 fulcrum, and the part of the cable (corresponding to the "cable" in this specification) that is bent in contact with the fulcrum corresponds to the bent part. In JP 2013-527893 A, the sliders (reference numerals 2a and 2b), the turn-back blocks (reference numerals 4a and 4b), and the motor (reference numeral 3) correspond to the "kite control unit" in this specification. In the system described in JP 2013-527893 A, the sliders are moved by the driving motor to control the cable length difference.

[0034] When the kite 2 is raised in the air, if the kite control unit 40 is used to make the length of the second rope longer than the length of the first rope, the flying object 20 swings so as to tilt to the left. On the other hand, if the kite control unit 40 is used to make the length of the first rope longer than the length of the second rope, the flying object 20 swings so as to tilt to the right. By alternately repeating the control of the kite 2 so as to tilt the flying object 20 to the left and to the right using the kite control unit 40, it is possible to intentionally adjust the flying object 20 to draw an eight-shaped trajectory. By adjusting the flying object 20 to draw an eight-shaped trajectory, it is possible to generate a high pulling force on the kite 2 downwind and upward.

[0035] 4 is a diagram for explaining a method of controlling a kite when adjusting the amplitude 11 of the horizontal figure-of-eight trajectory 10 of a flying object 20. When the flying object 20, which is tracing a figure-of-eight trajectory, reaches a predetermined position on the trajectory, the kite control unit 40 controls the left-right tilt of the kite 2, thereby changing (amplifying or attenuating) the amplitude 11 of the figure-of-eight trajectory 10.

[0036] As shown in Fig. 4, when the flying object 20 describes a trajectory so as to descend obliquely in the center of the figure-of-eight trajectory 10, in order to amplify the amplitude 11, the kite control unit 40 controls the cable length difference so that the flying object 20 tilts to the right when the flying object 20 is located near position M on the figure-of-eight trajectory 10 where the upward movement turns to downward movement in the left loop 10L in the figure. Furthermore, the kite control unit 40 controls the cable length difference so that the flying object 20 tilts to the left when the flying object 20 is located near position N on the figure-of-eight trajectory 10 where the upward movement turns to downward movement in the right loop 10R in the figure. By alternately performing this between the left and right, the amplitude 11 of the flying object 20 can be amplified. By increasing the amplitude 11 of the figure-of-eight trajectory 10, a difference in tension occurs between the left rope 21L and the right rope 21R, and when the tension exceeds a certain level, the flying object 20 begins to trace the horizontal figure-of-eight trajectory 10 by self-excited vibration without the kite control unit 40 actively controlling the rope length difference.

[0037] On the other hand, when the amplitude 11 is to be attenuated, the kite control unit 40 controls the cable length difference 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 ascending to descending. Furthermore, the kite control unit 40 controls the cable length difference so that the flying object 20 tilts rightward 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 ascending to descending. By alternately performing this between the left and right, the amplitude 11 of the flying object 20 can be attenuated.

[0038] The kite control unit 40 alternately executes a first operation in which the kite 2 uses the wind force received by the flying body 20 to pull the movable body 4 toward the downwind side 13, and a second operation in which the movable body 4 uses its own weight to move the movable body 4 toward the upwind side 12. The movement of the movable body 4 toward the downwind side 13 by the first operation is called "upward linear motion". The movement of the movable body 4 toward the upwind side 12 by the second operation is called "downward linear motion". The first operation is an operation in which the amplitude 11 of the figure-of-eight trajectory 10 of the flying body 20 is made relatively large, and the second operation is an operation in which the amplitude 11 is made relatively small. The magnitude of the pulling force received by the kite control unit 40 from the kite 2 in the first operation is greater than the magnitude of the pulling force received by the kite control unit 40 from the kite 2 in the second operation.

[0039] In this embodiment, the kite control unit 40 switches between the first operation and the second operation by changing the elevation angle of the kite 2. In detail, as shown in FIG. 2(C), the kite control unit 40 is used to attenuate the amplitude 11 of the flying object 20, thereby changing the pulling direction F of the kite 2 and increasing the elevation angle θ1 of the kite 2 to adjust it to the elevation angle θ2. By increasing the elevation angle of the kite 2, the flying object 20 becomes almost parallel to the wind direction W, and the pulling force on the leeward side 13 of the kite 2 is reduced. As a result, the resistance due to the wind force becomes smaller than the gravity, and the movable body 4 moves downward from the leeward side 13 to the windward side 12 of the inclined surface 60 under its own weight (downward linear motion). By repeating the upward linear motion and the downward linear motion, the movable body 4 can make a reciprocating motion on the guide rail 61.

[0040] The power generating mechanism 51 is fixedly disposed on the rotary table 64, and the power generating mechanism 51 is provided on the ground. The generator 5 converts the reciprocating motion of the movable body 4 into electric power. The generator 5 includes the power generating mechanism 51, a connecting unit 52, and a conversion mechanism 53. The power generating mechanism 51 includes, for example, a rotor having a magnet and a stator around which a coil is wound. One end of the connecting unit 52 is connected to the movable body 4, and the other end is connected to the conversion mechanism 53. The connecting unit 52 transmits the linear reciprocating motion of the movable body 4 to the conversion mechanism 53. The conversion mechanism 53 converts the transmitted linear reciprocating motion into rotational motion, and generates electric power by rotating the magnet in the coil using the rotational motion. The conversion mechanism 53 may be an eccentric cam mechanism, a rack and pinion mechanism, a slider crank mechanism, or the like. The conversion mechanism 53 may include a speed increasing gear or the like as necessary.

[0041] The configuration of the power generating mechanism 51 is not limited to the configuration described here. For example, in the present embodiment, an example has been given in which the linear reciprocating motion of a movable body is converted into rotational motion to generate electric power, but the power generating mechanism may be configured to generate electric power without converting the linear reciprocating motion into rotational motion. For example, electric power may be generated by linearly reciprocating a magnet in a coil.

[0042] [About the figure-of-eight orbit]

[0043] Fig. 3(A) is a schematic diagram for explaining the figure-of-eight trajectory 10 of the flying object 20, and Fig. 3(B) is a schematic diagram showing the forces (tension) acting on the right rope 21R and the left rope 21L when the flying object 20 flies on the figure-of-eight trajectory 10. When the flying object 20 flies on the figure-of-eight trajectory, the tension of the right rope 21R and the left rope 21L changes. As the flying object 20 rises due to the wind force, tension always acts on the rope 21, but on the figure-of-eight trajectory 10, especially when the flying object 20 descends, a large tension acts on the rope 21.

[0044] As shown in Fig. 3(A) and (B), in the descending vicinity a where the flying object 20 descends from left to right in the center of the figure-8 orbit 10, the tension acting on the left rope 21L and the right rope 21R becomes large. Furthermore, the tension acting on the left rope 21L becomes larger than the tension acting on the right rope 21R, and a tension difference occurs between the left and right. In the descending vicinity c where the flying object 20 descends from right to left in the center of the figure-8 orbit 10, the tension acting on the left rope 21L and the right rope 21R becomes large. Furthermore, the tension acting on the right rope 21R becomes larger than the tension acting on the left rope 21L, and a tension difference occurs between the left and right. In contrast, in the ascending vicinity b and ascending vicinity d where the flying object 20 ascends from bottom to top, the tension acting on the left rope 21L and the right rope 21R becomes small, and the tension difference between the left and right is also small.

[0045] The difference in tension between the left rope 21L and the right rope 21R at points a and c near the descent is believed to depend on the distance relationship between the flying object 20 and the fulcrums of the left and right ropes 21, in other words, the length of the first rope and the length of the second rope, and this is believed 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 complicated mechanism.

[0046] In the power generation device 1, wind power is utilized to fly the kite 2 in an eight-shaped trajectory 10 using the kite control unit 40, thereby generating a large amount of power, and this power is used to move the movable body 4 back and forth on the inclined surface 60, thereby efficiently generating electricity.

[0047] [Power generation method]

[0048] A method of generating electricity by the power generation device 1 will be described with reference to Fig. 2. In Fig. 2, the generator 5, battery 41, and carriage 141 are omitted to simplify the drawing. The same applies to Fig. 6 used in the description of the second embodiment described below. In the drawing, the arrow marked with the symbol W indicates the wind direction. The arrow marked with the symbol E indicates the traveling direction of the movable body 4. The arrow marked with the symbol F indicates the direction of the force generated by the flying body 20 (pulling direction).

[0049] As shown in FIG. 2(A), the position of the platform 62 is determined by rotating the rotary table 64 so that the inclination is upward from the windward side 12 to the leeward side 13 of the inclined surface 60. Initially, the movable body 4 is located on the windward side 12 of the inclined surface 60, the rope 21 is pulled out to a certain length, and the flying object 20 is placed on the leeward side 13 of the inclined surface 60. After that, the left rope 21L and the right rope 21R are evenly wound up by the right winch and the left winch until the rope length reaches a predetermined length, so that the flying object 20 receives the wind and rises. When the rope length of the rope 21 reaches a predetermined length, the use of each winch is stopped, and the winding and pulling out by each winch are not performed. In other words, the length of the rope 21 from each winch to the flying object 20 is fixed. After that, the kite control unit 40 is used to control the rope length difference to tilt the flying object 20 alternately left and right, and the attitude of the flying object 20 is adjusted so that it draws an eight-shaped trajectory. Then, as explained above with reference to FIG. 4, the kite control unit 40 controls the cable length difference so that the flying object 20 is inclined in the direction opposite to the predetermined position (right or left) of the flying object 20 when the flying object 20 is positioned at a predetermined position on the orbit 10, and the cable length difference is controlled by the kite control unit 40. By repeating this on the left and right sides, the flying object 20 is amplified in amplitude 11. A difference occurs between the tensions of the left cable 21L and the right cable 21R, and the flying object 20 is amplified in amplitude 11 until the tension of the cable 21 becomes equal to or greater than a certain level. Then, the control by the kite control unit 40 is stopped when the flying object 20 continues to describe the horizontal figure-8 orbit by self-excited vibration without active cable length difference variable control using the kite control unit 40.

[0050] The active control of the cable length difference by the kite control unit 40 may be performed manually or automatically based on image information obtained by capturing an image of the trajectory of the flying object 20 with a camera. For example, when amplifying the amplitude 11 of the figure-of-eight trajectory 10 of the flying object 20, the kite control unit 40 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. 4) based on the image information, and controls the kite 2 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. 4).

[0051] 2(B), the kite control unit 40 executes a first operation of amplifying the amplitude 11 of the figure-of-eight trajectory 10 of the flying body 20 and causing the kite 2 to pull the movable body 4 toward the leeward side 13 by utilizing the wind force received by the flying body 20. When the movable body 4 moves from the windward side 12 to the leeward side 13 of the inclined surface 60, the flying body 20 describes a compound periodic figure-of-eight trajectory.

[0052] In the above example, the kite control unit 40 triggers the flying object 20 to self-oscillate in the figure-of-eight orbit 10, and the control by the kite control unit 40 is stopped to cause the flying object 20 to self-oscillate in the figure-of-eight orbit. However, the control by the kite control unit 40 may be continued to make the flying object 20 forcibly oscillate in the figure-of-eight orbit 10. However, from the viewpoint of improving energy efficiency, it is preferable to stop the active control by the kite control unit 40 when the flying object 20 continues to describe the horizontal figure-of-eight orbit by self-oscillation without active cable length difference variable control. This makes it possible to reduce the energy consumed for the control of the kite control unit 40, and as a result, to improve the energy efficiency of the entire device.

[0053] Next, as shown in FIG. 2(C), when the movable body 4 reaches the leeward side 13 of the inclined surface 60, the kite control unit 40 switches from the first operation to the second operation by changing the elevation angle of the kite 2. The kite control unit 40 executes the second operation of moving the movable body 4 to the windward side 12 by utilizing the weight of the movable body 4. Specifically, the kite control unit 40 changes the pulling direction F of the kite 2 by attenuating the amplitude 11 of the figure-of-eight trajectory 10 of the flying body 20, and increases and adjusts the elevation angle θ1 of the kite 2 to the elevation angle θ2 (switching from the first operation to the second operation). In this way, by changing the amplitude 11 of the figure-of-eight trajectory 10 of the flying body 20 by the kite control unit 40, the elevation angle of the kite 2 can be changed without winding up the rope 21 with a winch. As the elevation angle increases, the flying body 20 becomes almost parallel to the wind direction, and the pulling force on the leeward side 13 of the kite 2 decreases. As a result, the movable body 4 moves down the inclined surface 60 toward the windward side 12 under its own weight, as shown in FIG. 2(D).

[0054] Next, as shown in Fig. 2(E), when the movable body 4 returns to the windward side 12 of the inclined surface 60, the kite control unit 40 controls the cable length difference to control the kite 2 so as to increase the amplitude 11 of the figure-of-eight trajectory of the flying body 20, and to change the elevation angle to decrease (switching from the second operation to the first operation). The kite control unit 40 again executes the first operation to make the kite 2 pull the movable body 4 toward the downwind side 13 by utilizing the wind force received by the flying body 20, as described with reference to Figs. 2(A) and (B).

[0055] 2(A) to (E) are repeated, that is, the kite control unit 40 alternately executes the first operation and the second operation, thereby making it possible to cause the movable body 4 to make a reciprocating motion on the inclined surface 60. Then, the generator 5 can convert the reciprocating motion of the movable body 4 on the inclined surface 60 into electricity.

[0056] FIG. 5 shows an example in which a kite is flown in a system by generating simulated wind, and the flying object can be made to vibrate by itself even if the control of the slider of the kite control unit 40 is stopped. FIG. 5 shows the changes in tension of each of the right rope 21R and the left rope 21L, the changes in the movement of the slider of the kite control unit 40, and the changes in the elevation angle and azimuth angle of each rope 21 when an experiment was conducted in which a movable body 4 to which a kite 2 is connected is towed by a towing vehicle traveling in a straight line at a constant speed (here, 26 km / h) on a plane to generate simulated wind and fly the flying object 20. While the towing vehicle is traveling, the cable lengths of the right and left ropes from the kite control unit 40 to the flying object 20 are kept constant, and here, the cable lengths of the right and left ropes are 45 m. The flying object 20 has a span length of 1346 mm and a wing area of ​​0.56 m. 2 The weight was 0.312 kg and the material used was ripstop polyester. During the experiment, the towing vehicle was driven from east to west in a southwesterly wind with a speed of 2 m / s.

[0057] In FIG. 5, the thick solid line indicates the change in the movement of the slider that constitutes part of the kite control unit 40. The thick solid line indicates the change in the elevation angle θRight of the right rope, which is the angle between the right rope 21R and the horizontal direction. The thin solid line indicates the change in the elevation angle θLeft of the left rope, which is the angle between the left rope 21L and the horizontal direction. The thick dashed line indicates the change in the azimuth angle ΦRight, which is the direction of the horizontal component of the right rope 21R based on the wind direction. The thin solid line indicates the change in the azimuth angle ΦLeft, which is the direction of the horizontal component of the left rope 21L based on the wind direction. The thin dashed line indicates the tension of the right rope 21R. The thick dashed line indicates the tension of the left rope 21L. The thick dashed line indicates the speed of the towing vehicle.

[0058] As shown in FIG. 5, in the experiment, when the towing vehicle starts to run, the kite 2 rises and the angle of elevation increases. For about 40 seconds after the start of running, the slider of the kite control unit 40 was used to perform variable cable length difference control to suppress the swaying of the flying object 20 so that the swaying of the flying object 20 would not become too large. After that, even when the control by the slider was stopped, it was confirmed that the kite 2 oscillated self-excitedly in an eight-shaped trajectory. In addition, as shown in FIG. 5 and FIG. 3(B), it was confirmed that a large tension was generated in the right cable 21R and the left cable 21L as the flying object 20 flew along an eight-shaped trajectory. It has not been fully elucidated what kind of aerodynamic system would cause the flying object to oscillate self-excitedly in a horizontal eight-shaped trajectory without active control by the slider, but it is thought that the self-excited vibration would occur when a difference in tension occurs in the two cables (left cable and right cable) connected to the flying object, and the tension of the cables reaches a certain level or more.

[0059] As described above, in the power generating device 1, the kite control unit 40 amplifies or attenuates the amplitude 11 of the figure-of-eight trajectory 10 of the flying object 20 to increase or decrease the tractive force toward the leeward side 13 of the kite 2, and uses this to move the movable object 4 back and forth on the inclined surface 60. By moving the movable object 4 back and forth in this manner, the moving range of the movable object can be reduced compared to the conventional method of towing a vehicle, and the safety area can be reduced. In addition, in the power generating method of the power generating device 1 of this embodiment, the elevation angle of the kite is changed by amplifying or attenuating the amplitude of the figure-of-eight trajectory to increase or decrease the tractive force toward the leeward side 13 of the kite 2, so the magnitude of the tractive force toward the leeward side 13 can be changed without significantly winding or unwinding the rope. In this way, in the power generating device 1, the length of the rope from the winch to the flying object 20 is not significantly changed, so the length of the rope can be shortened compared to the conventional method of towing a vehicle or the pumping cycle method, and the safety area can be reduced. Moreover, the power generating device 1 does not require large pillars or large rigid blades as in existing wind power generation facilities.

[0060] In this way, the power generating device 1 is highly safe, can alleviate restrictions on installation locations, can reduce installation and removal costs, and is unlikely to damage the scenery. For this reason, the power generating device is particularly effective for installation in areas where installation locations are likely to be restricted, such as areas near high-voltage power lines or coastlines close to residential houses, and where it is necessary to take into consideration the impact of falling. In addition, in the power generating device, the kite can be placed on the ground when the weather worsens, and damage from wind, snowfall, lightning, etc. can be avoided. Furthermore, in the power generating device 1, the kite control unit, the generator, etc., which are heavy objects, can be installed on the ground without being mounted on a flying object, so in addition to realizing a reduction in the safety area, safety can be improved without the risk of heavy objects falling. In contrast, for example, in a power generating device that mounts a heavy motor on a flying object and raises it into the sky to generate electricity, the safety area can be reduced, but there is a possibility that the motor will fall, reducing safety.

[0061] <Second embodiment>

[0062] In the above embodiment, the kite control unit 40 actively changes the amplitude 11 of the figure-of-eight trajectory 10 of the flying object 20 to change the elevation angle of the kite 2 to switch between the first operation and the second operation, but this is not limiting. For example, as in this embodiment, the movable body 4 may be reciprocated without actively changing the elevation angle of the kite 2. Hereinafter, the power generation method in this embodiment will be described with reference to Figures 3(A) and 6. The power generation device 1 used in this embodiment may be substantially the same as the power generation device in the first embodiment.

[0063] In the power generation method of the power generating device 1 of this embodiment, when the flying object 20 descends on the figure-of-eight orbit, the tension acting on the rope increases, making the traction force (referred to as the first traction force) relatively large, and when the flying object 20 ascends, the tension acting on the rope decreases, making the traction force (referred to as the second traction force) relatively small. Specifically, in this embodiment, the movable body 4 is configured to move to the leeward side 13 by utilizing the first traction force generated when the flying object 20 descends on the figure-of-eight orbit 10 of the flying object 20, and to move to the windward side 12 by utilizing the second traction force generated when the flying object 20 ascends and the weight of the movable body 4. Therefore, compared to the first embodiment, the stroke of the movable body 4 can be made smaller, and the overall length of the support 6 can be shortened. Therefore, the overall size of the power generating device can be made smaller, and the safety area can be made smaller.

[0064] Refer to FIG. 3(A). In this embodiment, as shown in FIG. 6(A), in the figure-of-eight trajectory 10, in the descending vicinity a where the flying body 20 descends from the left loop 10L to the right loop 10R, the movable body 4 moves to the downwind side 13 by using the first traction force (upward linear motion). Next, in the ascending vicinity b where the flying body 20 of the right loop 10R ascends, the movable body 4 moves to the upwind side 12 by using the second traction force and the weight of the movable body 4 (downward linear motion). Next, in the descending vicinity c where the flying body 20 descends from the right loop 10R to the left loop 10L, the movable body 4 moves to the downwind side 13 by using the first traction force (upward linear motion). Next, in the ascending vicinity d where the flying body 20 of the left loop 10L ascends, the movable body 4 moves to the upwind side 12 by using the second traction force and the weight of the movable body 4 (downward linear motion). Thus, in this embodiment, while the flying body 20 makes one revolution on the figure-of-eight trajectory (one cycle), the movable body 4 makes two reciprocating motions on the guide rail 61. In this embodiment, as in the first embodiment, the reciprocating motion of the movable body 4 is converted into electric power by the generator 5.

[0065] In this embodiment, as in the first embodiment, the safety area can be reduced, the power generation device can be made safer, restrictions on installation locations can be relaxed, installation and removal costs can be reduced, and the device is less likely to spoil the scenery.

[0066] In addition, in this embodiment, there is no need to actively change the elevation angle of the kite, and the energy used to control the kite control unit to change the elevation angle can be reduced, thereby improving energy efficiency.

[0067] <Modification>

[0068] 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. In addition, it goes without saying that the scope of the present invention is not limited to these embodiments.

[0069] [Variation 1]

[0070] In the above embodiment, the kite 2 has two cords 21, but the present invention is not limited to this and may have two or more cords 21. In order to make the flying object 20 fly in an eight-shaped trajectory, at least one rope is connected to each of the left and right ends of the flying object 20 and to the movable body.

[0071] [Variation 2]

[0072] In the above embodiment, an example was given in which the inclination of the inclined surface 60 having the guide rail 61 was fixed, but the power generating device 1 may have a change mechanism that changes the inclination of the inclined surface 60 having the guide rail 61 according to wind speed conditions. As a method for changing the inclination of the inclined surface 60 having the guide rail 61, the inclination of the guide rail 61 alone may be changed, or the inclination of the inclined surface 60 of the base 62 to which the guide rail 61 is fixed may be changed. In this way, when the movable body 4 moves to the windward side 12 (during downward linear movement), if the resistance due to the wind force is greater than gravity and it is difficult for the movable body 4 to move downward under its own weight, the inclination of the guide rail 61 can be changed to be steeper by the change mechanism, thereby facilitating the downward movement of the movable body 4.

[0073] [Variation 3]

[0074] A power generating device 1A as a modified example will be described with reference to Fig. 7. Configurations similar to those in the above-described embodiment are given the same reference numerals and descriptions thereof will be omitted.

[0075] In the above-described embodiment, the degree of inclination of the inclined surface 60 is uniform and does not change from the windward side 12 to the leeward side 13, but as in the power generating device 1A shown in Fig. 7, the inclined surface 60A of the support body 6A and the guide rail 61A may be configured so that the degree of inclination increases from the windward side 12 to the leeward side 13. This makes it possible for the movable body 4 moving on the guide rail 61A to easily descend toward the windward side 12 after proceeding toward the leeward side 13 for a certain distance or more, thereby facilitating the downward movement of the movable body 4.

[0076] [Variation 4]

[0077] In the above-described embodiment, when the resistance of the movable body 4 due to wind force is greater than gravity during the downward linear motion, and it is difficult for the movable body 4 to move downward due to its own weight, a biasing mechanism may be provided to bias the movable body 4 located on the leeward side 13 to move downward from the leeward side 13 toward the windward side 12. Here, in the power generating device 1, a stopper (not shown) that limits the upward movement of the movable body 4 is typically provided near the tip of the leeward side 13 of the guide rail 61 of the inclined surface 60, so that the movable body 4 does not fall from the support 6. As the biasing mechanism, for example, a stopper may be formed of an elastic body, and the movable body 4 that collides with the stopper is bounced off by the elasticity of the stopper, and the momentum of the movable body 4 moving downward is gained, so that the downward movement of the movable body 4 can be promoted. As another biasing mechanism, magnets may be provided on the stopper and the movable body 4 so as to repel each other when the stopper and the movable body 4 approach each other. The repulsion between the magnet of the movable body 4 approaching the stopper and the magnet of the stopper creates momentum for the downward movement of the movable body 4, and can promote the downward movement of the movable body 4. As yet another biasing mechanism, a traction mechanism may be provided that tractionally pulls the movable body 4 from the leeward side 13 to the windward side 12. The traction mechanism may create momentum for the downward movement of the movable body 4, and can promote the downward movement of the movable body 4. The traction mechanism may be configured, for example, to connect the movable body 4 and the power generation mechanism 51 with a connecting cord, and to wind up the connecting cord on the power generation mechanism 51 side to pull the movable body 4.

[0078] In the above, the biasing mechanism for biasing the movable body 4 located on the leeward side to move in the downward direction has been described, but a biasing mechanism for biasing the movable body 4 located on the windward side to move in the upward direction from the windward side 12 to the leeward side 13 may be provided. As the biasing mechanism for biasing the movable body 4 to move in the upward direction, the same biasing mechanism for biasing the movable body 4 to move in the downward direction as described above may be used. That is, a stopper that is provided near the tip of the windward side 12 of the guide rail 61 of the inclined surface 60 and restricts the downward movement of the movable body 4 to prevent the movable body 4 from falling from the support 6 may be made of an elastic body. In this way, the movable body 4 that collides with the stopper is bounced off by the elasticity of the stopper, and the momentum of the movable body 4 moving in the upward direction can be gained. In addition, as another biasing mechanism, magnets are provided so as to repel each other when they approach the stopper and the movable body 4, and the momentum of the movable body 4 moving in the upward direction can be gained by utilizing the repulsion of the magnets. Furthermore, as another biasing mechanism, a traction mechanism may be provided that traction the movable body 4 from the windward side 12 toward the leeward side 13, and the traction mechanism may provide momentum for the upward movement of the movable body 4.

[0079] In this way, by providing a biasing mechanism for biasing the movable body 4 to move in the downward direction and / or a biasing mechanism for biasing the movable body 4 to move in the upward direction, the reciprocating motion of the movable body 4 can be assisted.

[0080] [Variation 5]

[0081] In addition to or instead of the rotating table 64, a rotating mechanism may be installed under the guide rail 61 to make it possible to adjust the extending direction of the guide rail 61 within the inclined surface 60. This makes it possible to adjust the wind direction and the extending direction of the guide rail 61 to be approximately parallel, thereby making it possible to utilize the wind force more efficiently.

[0082] [Variation 6]

[0083] In the first embodiment described above, the rope may be rapidly withdrawn from the winch after the change in the elevation angle of the kite 2 (phase in FIG. 2(C)) that is performed when switching from the first operation to the second operation is completed. This allows the pulling force to be rapidly reduced, which is advantageous for the reciprocating motion of the movable body 4. Note that if the rope is rapidly withdrawn when the elevation angle is low, the kite 2 may crash, so this is preferably performed when the elevation angle is at a certain level.

[0084] In the first embodiment described above, the rope 21 may be wound up by a winch after the change in the elevation angle of the kite 2 (phase (E) in FIG. 2) is completed when switching from the second operation to the first operation. This increases the airspeed of the kite 2 and the pulling force, which is advantageous for reciprocating motion.

[0085] [Variation 7]

[0086] In the above-described first embodiment, as shown in FIG. 3(A), the flying direction of the flying body 20 on the figure-8 trajectory 10 is set so that the flying body 20 descends in the center of the figure-8 trajectory 10 (near the area between the left loop 10L and the right loop 10R), but the flying body 20 may also ascend.

[0087] [Variation 8]

[0088] In the above-described first embodiment, an example has been given in which the movable body 4 is located on the windward side 12 of the inclined surface 60 when the flying body takes off (see FIG. 2(A)), but it may be located on the leeward side 13. In this case, by winding the rope with a winch while lowering the movable body 4, the descent speed, as well as the winch winding speed and wind speed, become speeds that contribute to takeoff, allowing the flying body 20 to fly more efficiently, which is advantageous for efficient power generation. [Explanation of symbols]

[0089] 1, 1A…Power generating equipment 2. Kite 20…flying object 21L…Left rope (first rope) 21R…Right side rope (second rope) 4...Movable body 40…Kite control unit 5. Generator 51...Power generation mechanism 52...Connection part 6, 6A…Support 60…Slope surface 61, 61A...Guide rail 64…Rotary table 10…figure 8 orbit 12…Windward 13…leeward side

Claims

1. A support having an inclined surface that is inclined upward from the windward side to the leeward side; a kite having a flying body and a first line and a second line connected to the flying body; a kite control unit connected to the first rope and the second rope, capable of flying the flying object in an eight-shaped trajectory in the air by changing a rope length difference between the length of the first rope and the length of the second rope, and a movable body configured to be capable of reciprocating motion to the leeward side and the windward side on the inclined surface depending on the magnitude of the pulling force received from the kite; a generator including a power generation mechanism installed on the ground and a connecting portion connecting the power generation mechanism and the movable body, the generator converting the reciprocating motion of the movable body on the inclined surface into electric power; A power generation device comprising:

2. The power generating device according to claim 1 , The kite control unit alternately executes a first operation for causing the kite to pull the movable body toward the downwind side by utilizing the wind force received by the flying object, and a second operation for moving the movable body toward the upwind side by utilizing the own weight of the movable body. Power generation equipment.

3. The power generating device according to claim 2, The kite control unit switches between the first operation and the second operation by changing the elevation angle of the kite. Power generation equipment.

4. The power generating device according to claim 1 , The movable body alternately moves to the downwind side using a first tractive force generated when the flying body descends on the figure-of-eight trajectory, and moves to the upwind side using a second tractive force smaller than the first tractive force and the movable body's own weight generated when the flying body ascends on the figure-of-eight trajectory. Power generation equipment.

5. The power generating device according to any one of claims 1 to 4, The kite control unit is configured to be able to trigger the flying object to oscillate in an eight-shaped orbit in the air or to oscillate self-excited in an eight-shaped orbit by changing the cable length difference. Power generation equipment.

6. The power generating device according to any one of claims 1 to 4, The support further includes a rotary table capable of changing the orientation of the inclined surface. Power generation equipment.

7. The power generating device according to any one of claims 1 to 4, The inclined surface has a guide rail for guiding the movement of the movable body. Power generation equipment.

8. The power generating device according to any one of claims 1 to 4, The inclined surface has an inclination that increases from the windward side to the leeward side. Power generation equipment.

9. The power generating device according to any one of claims 1 to 4, The system further includes a biasing mechanism for biasing the movable body located on the leeward side to move in a direction from the leeward side to the windward side, and / or a biasing mechanism for biasing the movable body located on the windward side to move in a direction from the windward side to the leeward side. Power generation equipment.

Images