Wave power generators and wave power generation systems

Abstract

Expand the frequency band of waves that can be used to generate electricity. [Solution] The wave power generator 1 comprises a movable structure 2, a permanent magnet 3, an armature structure 4, and a control unit 5. The control unit 5 includes a first permanent magnet 51 and a second permanent magnet 52 provided on the movable structure 2, a magnetic body 53 provided on the armature structure 4, a first coil 54 and a second coil 55 provided on the first permanent magnet 51 and the second permanent magnet 52 respectively, and a power supply unit 56 that supplies current to the first coil 54 and the second coil 55. In the first state, the magnetic path of the first permanent magnet 51 becomes a closed magnetic path passing through the magnetic body 53, and in the second state, it becomes a closed magnetic path passing through the magnetic body 53. The control unit 5 controls the magnitude of the magnetic attractive force between the first permanent magnet 51 and the magnetic body 53 by controlling the current supplied by the power supply unit 56 to the first coil 54, and controls the magnitude of the magnetic attractive force between the second permanent magnet 52 and the magnetic body 53 by controlling the current supplied by the power supply unit 56 to the second coil 55.

Description

Technical Field

[0001] The present disclosure relates to a wave power generator and a wave power generation system.

Background Art

[0002] Patent Document 1 discloses a wave power generation device including a shaft portion having a rod-shaped permanent magnet and a conductive coil through which the shaft portion is movably inserted in the longitudinal direction, and connecting a float to either the shaft portion or the coil, and generating power by relatively repeatedly reciprocating the shaft portion and the coil in the longitudinal direction of the shaft portion by the vertical movement of the float due to the wave. Patent Document 2 discloses a wave power generation system including a floating body container, a power generation unit disposed inside the floating body container, and a connection mechanism for attaching the power generation unit to a structure installed on the sea. Patent Document 3 discloses a wave power generation assembly having a hull and a linear generator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the wave power generation device as described in Patent Document 1, in order to cause the vertical movement of the floating body by the wave, it is desirable that the natural frequency of the floating body coincides with the frequency of the wave. Therefore, the sea conditions under which power can be generated are limited, and there is a possibility that the operating rate of the wave power generation device may decrease depending on the sea conditions.

[0005] This disclosure aims to provide a wave power generator and a wave power generation system that can expand the frequency band of waves that can generate electricity. [Means for solving the problem]

[0006] The wave power generator of the present disclosure comprises: [1] a movable structure that can vibrate by waves; a power generation field section provided on the movable structure; an armature structure having a power generation coil, wherein an induced electromotive force is generated when the magnetic flux of the power generation field section passing through the power generation coil changes; and a control unit, wherein the control unit comprises a control field section provided on one of the movable structure and the armature structure; a magnetic material provided on the other of the movable structure and the armature structure; a control coil provided on one of the control field section and the magnetic material; and an electric field section for the control coil. A wave power generator comprising a power supply unit that supplies current, wherein the magnetic path of the control field unit is a closed magnetic path passing through the magnetic material in a first state where the position of the movable structure in the vibration direction of the movable structure relative to the armature structure is a first position, and in a second state where the position of the movable structure in the vibration direction of the armature structure is a second position different from the first position, and the control unit controls the magnitude of the magnetic attractive force between the control field unit and the magnetic material by controlling the current supplied by the power supply unit to the control coil.

[0007] In the wave power generator described in [1] above, the power supply unit controls the current supplied to the control coil, thereby controlling the magnitude of the magnetic attraction force between the control field unit, which is provided on one of the movable structure and the armature structure, and the magnetic material, which is provided on the other of the movable structure and the armature structure. This makes it possible to control the nonlinearity of the vibration of the movable structure relative to the armature structure. By utilizing the nonlinearized vibration of the movable structure, the frequency band of waves that the movable structure can vibrate can be expanded. Therefore, the wave power generator described in [1] above can expand the frequency band of waves that can generate electricity.

[0008] The wave power generator of the present disclosure may also be [2] "the wave power generator according to [1], wherein the control field section has a first field section and a second field section, the first field section is provided such that in the first state the magnetic path of the first field section becomes a closed magnetic path passing through the magnetic material, and the second field section is provided at a position different from the first field section in the direction of vibration such that in the second state the magnetic path of the second field section becomes a closed magnetic path passing through the magnetic material." In this case, an embodiment in which the magnetic path of the control field section becomes a closed magnetic path in the first and second states can be suitably realized.

[0009] The wave power generator of the present disclosure may also be the wave power generator described in [2], [3] "the control coil having a first coil and a second coil provided in the first field section and the second field section, respectively, the control unit controls the magnitude of the magnetic attractive force between the first field section and the magnetic material by controlling the current supplied by the power supply section to the first coil, and the control unit controls the magnitude of the magnetic attractive force between the second field section and the magnetic material by controlling the current supplied by the power supply section to the second coil." In this case, the nonlinearity of the vibration of the movable structure with respect to the armature structure can be suitably controlled. For example, when the position of the movable structure is close to the first position, the vibration of the movable structure can be increased by controlling the magnitude of the magnetic attractive force between the second field section and the magnetic material. Also, when the position of the movable structure is close to the second position, the vibration of the movable structure can be increased by controlling the magnitude of the magnetic attractive force between the first field section and the magnetic material.

[0010] The wave power generator of the present disclosure may also be [4] "the wave power generator according to any one of [1] to [3], wherein the magnetic material comprises a first magnetic material and a second magnetic material, the first magnetic material is provided such that in the first state the magnetic path of the control field section becomes a closed magnetic path passing through the first magnetic material, and the second magnetic material is provided at a position different from the first magnetic material in the direction of vibration such that in the second state the magnetic path of the control field section becomes a closed magnetic path passing through the second magnetic material." In this case, an embodiment in which the magnetic path of the control field section becomes a closed magnetic path in the first and second states can be suitably realized.

[0011] The wave power generator of the present disclosure may also be the wave power generator described in [4], [5] "the control coil having a first coil and a second coil provided on the first magnetic material and the second magnetic material, respectively, the control unit controls the magnitude of the magnetic attractive force between the control field unit and the first magnetic material by controlling the current supplied by the power supply unit to the first coil, and the control unit controls the magnitude of the magnetic attractive force between the control field unit and the second magnetic material by controlling the current supplied by the power supply unit to the second coil." In this case, the nonlinearity of the vibration of the movable structure with respect to the armature structure can be suitably controlled. For example, when the position of the movable structure is close to the first position, the vibration of the movable structure can be increased by controlling the magnitude of the magnetic attractive force between the control field unit and the second magnetic material. Also, when the position of the movable structure is close to the second position, the vibration of the movable structure can be increased by controlling the magnitude of the magnetic attractive force between the control field unit and the first magnetic material.

[0012] The wave power generator of the present disclosure may also be [6] "the wave power generator according to any one of [1] to [5], wherein the control unit has a sensor for detecting position information indicating the position of the movable structure in the vibration direction relative to the armature structure, and the power supply unit controls the current supplied to the control coil based on the position information." In this case, the nonlinearity of the vibration of the movable structure can be appropriately controlled according to the position of the movable structure.

[0013] The wave power generator of this disclosure may also be a wave power generator according to any one of [1] to [6], wherein the armature structure is capable of vibrating along the direction of vibration due to waves. In this case, the options for locations where the wave power generator can be installed can be increased.

[0014] The wave power generator of this disclosure may also be [8] "a wave power generator according to any one of [1] to [6] wherein the armature structure is fixed to a fixed structure on land." In this case, the stability of the armature structure can be ensured.

[0015] The wave power generation system of the present disclosure is a "wave power generation system including a plurality of wave power generators each being the wave power generator described in any one of [1] to [8], and an electrical system for transmitting and receiving the electric power generated by each of the plurality of wave power generators". In this case, for example, by generating electricity using a wave power generator that is relatively easy to generate electricity according to the sea state, electricity can be generated efficiently.

Effects of the Invention

[0016] According to the present disclosure, it is possible to provide a wave power generator and a wave power generation system capable of expanding the frequency band of waves that can be generated.

Brief Description of the Drawings

[0017] [Figure 1] FIG. 1 is a configuration diagram of a wave power generation system according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a wave power generator included in the wave power generation system shown in FIG. 1. [Figure 3] FIG. 3 is a perspective view of a magnetic body included in the wave power generator shown in FIG. 2. [Figure 4] (a) of FIG. 4 is a cross-sectional view showing the positional relationship of the first permanent magnet, the second permanent magnet, and the magnetic body in the first state, and (b) of FIG. 4 is a cross-sectional view showing the positional relationship of the first permanent magnet, the second permanent magnet, and the magnetic body in the second state. [Figure 5] FIG. 5 is a top view of the first permanent magnet and the magnetic body in the first state as viewed from above. [Figure 6] FIG. 6 is a flowchart showing a method for controlling the vibration of a movable structure by a control unit. [Figure 7] FIG. 7 is a diagram for explaining an example of a method for controlling the vibration of a movable structure by a control unit. [Figure 8] FIG. 8 is a graph showing the temporal change in the position of the first permanent magnet. [Figure 9] FIG. 9 is a diagram for explaining an example of a method for controlling the vibration of a movable structure by a control unit. [Figure 10] FIG. 10 is a graph showing the temporal change of the position of the second permanent magnet. [Figure 11] FIG. 11 is a graph showing the relationship between each of the magnetic attractive force and the buoyant force acting on the movable structure and the displacement of the movable structure. [Figure 12] FIG. 12 is a graph showing the relationship between the potential energy of the movable structure and the displacement of the floating body. [Figure 13] (a) of FIG. 13 is a cross-sectional view showing a first modification of the arrangement configuration of the permanent magnet and the magnetic body, (b) of FIG. 13 is a cross-sectional view showing the positional relationship of the permanent magnet, the first magnetic body, and the second magnetic body in the first state, and (c) of FIG. 13 is a cross-sectional view showing the positional relationship of the permanent magnet, the first magnetic body, and the second magnetic body in the second state. [Figure 14] (a) of FIG. 14 is a cross-sectional view showing a second modification of the arrangement configuration of the permanent magnet and the magnetic body, (b) of FIG. 14 is a cross-sectional view showing the positional relationship of the three permanent magnets and the two magnetic bodies in the first state, and (c) of FIG. 14 is a cross-sectional view showing the positional relationship of the three permanent magnets and the two magnetic bodies in the second state. [Figure 15] (a) of FIG. 15 is a cross-sectional view showing a third modification of the arrangement configuration of the permanent magnet and the magnetic body, (b) of FIG. 15 is a cross-sectional view showing the positional relationship of the four permanent magnets and the magnetic body in the first state, and (c) of FIG. 15 is a cross-sectional view showing the positional relationship of the four permanent magnets and the magnetic body in the second state. [Figure 16] FIG. 16 is a side view of the wave power generator according to the modification as viewed from the side. [Embodiments for Carrying Out the Invention]

[0018] Hereinafter, with reference to the drawings, a preferred embodiment of a wave power generator and a wave power generation system including the same according to an embodiment of the present disclosure will be described in detail. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant descriptions are omitted. [Wave Power Generation System]

[0019] Figure 1 is a diagram illustrating the configuration of a wave power generation system according to one embodiment. As shown in Figure 1, the wave power generation system 10 comprises a plurality of wave power generators 1 and an electrical system 11. The wave power generators 1 are located on the sea and generate electricity using waves on the sea surface S. The electrical system 11 includes a power storage device 12 located on the sea and electric wires 13 that electrically connect the power storage device 12 and the wave power generators 1. The electrical system 11 receives and transmits electricity generated by each wave power generator 1 via the electric wires 13. The power storage device 12 stores the electricity. The electrical system 11 may supply the electricity generated by one wave power generator 1 to other wave power generators 1. The electrical system 11 may transmit the generated electricity to an onshore electrical system.

[0020] Figure 2 is a cross-sectional view of the wave power generator 1 included in the wave power generation system 10 shown in Figure 1. The wave power generator 1 is a wave power generator employing a so-called linear type. The wave power generator 1 comprises a movable structure 2, two permanent magnets 3 (power generation field section), an armature structure 4, and a control unit 5.

[0021] The movable structure 2 is a floating body positioned on the sea surface, capable of vibrating along direction D1 (vibration direction) due to waves. The movable structure 2 is formed in a rod shape extending along direction D1. Direction D1 is, for example, the vertical direction.

[0022] The two permanent magnets 3 are located approximately in the center of the movable structure 2 in direction D1 and are aligned in direction D1. The permanent magnets 3 are formed in a rod shape extending along direction D2, which is perpendicular to direction D1. In this embodiment, the north pole of the permanent magnet 3 is located on the left side of Figure 2, and the south pole of the permanent magnet 3 is located on the right side of Figure 2.

[0023] The armature structure 4 is a floating body positioned on the sea and capable of vibrating along direction D1 due to waves. The armature structure 4 has a pair of coil sections 41. The pair of coil sections 41 are spaced apart in direction D2. Each of the pair of coil sections 41 is a three-phase coil, comprising a U-phase coil 41a (power generation coil), a V-phase coil 41b (power generation coil), and a W-phase coil 41c (power generation coil). Each of the coils 41a to 41c is wound around an axis parallel to direction D2. Note that the coil sections 41 do not necessarily have to be three-phase coils.

[0024] The movable structure 2 is held in such a way that it can vibrate relative to the armature structure 4. For example, the movable structure 2 is placed inside a cylindrical member (not shown) that extends along a direction D1 and is fixed to the armature structure 4, and vibrates along direction D1 within the cylindrical member. As a result, the movable structure 2 vibrates along direction D1 relative to the armature structure 4.

[0025] The movable structure 2 is positioned between a pair of coil sections 41. The magnetic flux of the permanent magnet 3 passes through the coils 41a to 41c. The magnetic flux of the permanent magnet 3 passing through the coils 41a to 41c changes as the movable structure 2 vibrates due to waves. This change in magnetic flux induces an electromotive force in the coils 41a to 41c, causing the wave power generator 1 to generate electricity.

[0026] The control unit 5 includes a first permanent magnet 51 (first field section), a second permanent magnet 52 (second field section), a magnetic material 53, a first coil 54 (control coil), a second coil 55 (control coil), a power supply unit 56, and a position sensor 57 (sensor).

[0027] The first permanent magnet 51 and the second permanent magnet 52 are provided on the upper part of the movable structure 2 and are aligned in direction D1. The first permanent magnet 51 is located above the second permanent magnet 52. In other words, the second permanent magnet 52 is provided at a different position from the first permanent magnet 51 in direction D1. Each of the first permanent magnet 51 and the second permanent magnet 52 is formed in a rod shape extending along direction D2. In this embodiment, the north poles of the first permanent magnet 51 and the second permanent magnet 52 are located on the left side of Figure 2, and the south poles of the first permanent magnet 51 and the second permanent magnet 52 are located on the right side of Figure 2.

[0028] The magnetic body 53 is provided on the upper part of the armature structure 4. The magnetic body 53 is made of a metallic material such as iron. Figure 3 is a perspective view of the magnetic body 53 of the wave power generator 1 shown in Figure 2. The magnetic body 53 has a rectangular annular frame portion 53a and a pair of protrusions 53b that project inward from the frame portion 53a. The pair of protrusions 53b are spaced apart and face each other in direction D2.

[0029] The movable structure 2 is positioned inside the frame portion 53a. The pair of protrusions 53b sandwich the movable structure 2 in direction D2. As the movable structure 2 and the armature structure 4 vibrate along direction D1, the positional relationship between the first permanent magnet 51, the second permanent magnet 52, and the magnetic material 53 changes.

[0030] Figure 4(a) is a cross-sectional view showing the positional relationship between the first permanent magnet 51, the second permanent magnet 52, and the magnetic material 53 in the first state, where the position of the movable structure 2 in direction D1 relative to the armature structure 4 is the first position, and Figure 4(b) is a cross-sectional view showing the positional relationship between the first permanent magnet 51, the second permanent magnet 52, and the magnetic material 53 in the second state, where the position of the movable structure 2 in direction D1 relative to the armature structure 4 is the second position. The first state shown in Figure 4(a) is a state in which the movable structure 2 has moved downward relative to the armature structure 4 from the state in Figure 2. The second state shown in Figure 4(b) is a state in which the movable structure 2 has moved upward relative to the armature structure 4 from the state in Figure 2. Thus, the first position and the second position are different positions in direction D1.

[0031] As shown in Figure 4(a), in the first state, the first permanent magnet 51 is positioned between the pair of protrusions 53b. That is, in the first state, the north and south poles of the first permanent magnet 51 face the pair of protrusions 53b, respectively. As shown in Figure 4(b), in the second state, the second permanent magnet 52 is positioned between the pair of protrusions 53b. That is, in the second state, the north and south poles of the second permanent magnet 52 face the pair of protrusions 53b, respectively.

[0032] Figure 5 is a top view of the first permanent magnet 51 and magnetic material 53 in the first state, viewed from above. In the first state, the magnetic flux of the first permanent magnet 51 passes through one of the pair of protrusions 53b (left side in Figure 5), the frame 53a, and the other of the pair of protrusions 53b (right side in Figure 5) in sequence, returning to the first permanent magnet 51 via a path (magnetic path M1). In other words, the magnetic path M1 of the first permanent magnet 51 is a closed magnetic path that passes through the magnetic material 53 in the first state. Similarly, in the second state, the magnetic flux of the second permanent magnet 52 passes through one of the pair of protrusions 53b (left side in Figure 5), the frame 53a, and the other of the pair of protrusions 53b (right side in Figure 5) in sequence, returning to the second permanent magnet 52 via a path (magnetic path M1). In other words, the magnetic path of the second permanent magnet 52 becomes a closed magnetic path that passes through the magnetic material 53 in the second state.

[0033] Thus, in the wave power generator 1, the first permanent magnet 51 is positioned such that in the first state, its magnetic path becomes a closed magnetic path passing through the magnetic material 53. A magnetic attractive force is generated between the first permanent magnet 51 and the magnetic material 53, such that the magnetic flux of the first permanent magnet 51 passes through the closed magnetic path formed by the magnetic material 53. In other words, a magnetic attractive force is generated that brings the movable structure 2 closer to the first position. Furthermore, the second permanent magnet 52 is positioned at a different location from the first permanent magnet 51 in direction D1, such that in the second state, its magnetic path becomes a closed magnetic path passing through the magnetic material 53. A magnetic attractive force is generated between the second permanent magnet 52 and the magnetic material 53, such that the magnetic flux of the second permanent magnet 52 passes through the closed magnetic path formed by the magnetic material 53. In other words, a magnetic attractive force is generated that brings the movable structure 2 closer to the second position.

[0034] Returning to Figure 2, the first coil 54 is provided (wound around) the first permanent magnet 51. The second coil 55 is provided (wound around) the second permanent magnet 52. In other words, the first coil 54 and the second coil 55 are provided at different positions in direction D1. The power supply unit 56 supplies current to the first coil 54 and the second coil 55, respectively. The power supply unit 56 includes, for example, a current source that generates current and a control unit that controls said current. The control unit includes a microcomputer that includes a CPU (Central Processing Unit) which is a processor, RAM (Random Access Memory) or ROM (Read Only Memory) which is a recording medium, a communication module, and an input / output module, etc.

[0035] When the power supply unit 56 supplies current to the first coil 54, the magnetic field generated by the first coil 54 increases the magnetic attractive force between the first permanent magnet 51 and the magnetic material 53. In this way, the control unit 5 controls the magnitude of the magnetic attractive force between the first permanent magnet 51 and the magnetic material 53 by controlling the current supplied by the power supply unit 56 to the first coil 54. Similarly, when the power supply unit 56 supplies current to the second coil 55, the magnetic field generated by the second coil 55 increases the magnetic attractive force between the second permanent magnet 52 and the magnetic material 53. In this way, the control unit 5 controls the magnitude of the magnetic attractive force between the second permanent magnet 52 and the magnetic material 53 by controlling the current supplied by the power supply unit 56 to the second coil 55.

[0036] The power supply unit 56 may be a single power supply unit for both the first coil 54 and the second coil 55, or, as shown in Figures 7 and 9 later, it may consist of a power supply unit 56A that supplies current to the first coil 54 and a power supply unit 56B that supplies current to the second coil 55.

[0037] The position sensor 57 is connected to the power supply unit 56 in a communicative manner. The position sensor 57 is a sensor for detecting position information indicating the position of the movable structure 2 in direction D1 with respect to the armature structure 4. The position sensor 57 may also detect position information indicating the positions of the first permanent magnet 51 and the second permanent magnet 52 in direction D1 with respect to the armature structure 4. [Control Method]

[0038] Referring to Figure 6, the method for controlling the vibration of the movable structure 2 by the control unit 5 will be explained. Figure 6 is a flowchart showing the method for controlling the vibration of the movable structure 2 by the control unit 5.

[0039] In step S1, the position sensor 57 detects position information indicating the position of the movable structure 2 in direction D1 relative to the armature structure 4. The position sensor 57 detects, for example, position information indicating that the position of the movable structure 2 is close to the first position, or that the position of the movable structure 2 is close to the second position.

[0040] In step S2, the power supply unit 56 (the control unit of the power supply unit 56) determines, based on the position information detected in step S1, that one of the coils, the first coil 54 and the second coil 55, will be the coil to which the current will be supplied.

[0041] In step S3, the power supply unit 56 supplies current to the coil (first coil 54 or second coil 55) determined in step S2.

[0042] Referring to Figures 7 and 8, a control method will be described when position information indicating that the position of the movable structure 2 is close to the second position (the second permanent magnet 52 is close to the magnetic material 53) is detected in step S1. Figure 7 is a diagram illustrating an example of a method for controlling the vibration of the movable structure 2 by the control unit 5. Figure 8 is a graph showing the temporal change in the position of the first permanent magnet 51.

[0043] As shown in Figure 7, when the position of the movable structure 2 is close to the second position, in step S2, the power supply unit 56A determines the first coil 54 as the destination for the current supply. Subsequently, in step S3, the power supply unit 56A supplies current to the first coil 54. This increases the magnetic attractive force between the first permanent magnet 51 and the magnetic material 53. As a result, the vibration of the movable structure 2 is controlled so that the position of the movable structure 2 approaches the first position (the first permanent magnet 51 approaches the magnetic material 53). In this case, as shown in Figure 8, after current is supplied to the first coil 54, the first permanent magnet 51 moves downward relative to the armature structure 4. In Figure 8, the position of the first permanent magnet 51 is shown as a dotted line, the current supplied to the first coil 54 is shown as a solid line, and the timing of supplying current to the first coil 54 is shown as "current on". Before the current is supplied, the first permanent magnet 51 is stationary at the top, but after the current is supplied, the first permanent magnet 51 swings significantly downward.

[0044] Referring to Figures 9 and 10, a control method will be described when position information indicating that the position of the movable structure 2 is close to the first position (the first permanent magnet 51 is close to the magnetic material 53) is detected in step S1. Figure 9 is a diagram illustrating an example of a method for controlling the vibration of the movable structure 2 by the control unit 5. Figure 10 is a graph showing the temporal change in the position of the second permanent magnet 52.

[0045] As shown in Figure 9, when the position of the movable structure 2 is close to the first position, in step S2, the power supply unit 56B determines the second coil 55 as the destination for the current supply. Subsequently, in step S3, the power supply unit 56B supplies current to the second coil 55. This increases the magnetic attractive force between the second permanent magnet 52 and the magnetic material 53. As a result, the vibration of the movable structure 2 is controlled so that the position of the movable structure 2 approaches the second position (the second permanent magnet 52 approaches the magnetic material 53). In this case, as shown in Figure 10, the second permanent magnet 52 moves upward relative to the armature structure 4 after current is supplied to the second coil 55. In Figure 10, the position of the second permanent magnet 52 is shown as a dotted line, the current supplied to the second coil 55 is shown as a solid line, and the timing of supplying current to the second coil 55 is shown as "current on". Before the current is supplied, the second permanent magnet 52 remains stationary at the bottom, but after the current is supplied, the second permanent magnet 52 swings significantly upward. [Mechanism of Action and Effects]

[0046] As explained above, in the wave power generator 1, the magnitude of the magnetic attractive force between the first permanent magnet 51 provided on the movable structure 2 and the magnetic material 53 provided on the armature structure 4 is controlled by the power supply unit 56 controlling the current supplied to the first coil 54. Furthermore, the magnitude of the magnetic attractive force between the second permanent magnet 52 provided on the movable structure 2 and the magnetic material 53 provided on the armature structure 4 is controlled by the power supply unit 56 controlling the current supplied to the second coil 55. This makes it possible to control the nonlinearity of the vibration of the movable structure 2 relative to the armature structure 4. By utilizing the nonlinearized vibration of the movable structure 2, the frequency band of waves that the movable structure 2 can vibrate can be expanded. Therefore, the wave power generator 1 can expand the frequency band of waves that can generate electricity.

[0047] The above actions and effects are supplemented with reference to Figure 11. Figure 11 is a graph showing the relationship between the magnetic attractive force, the buoyant force acting on the movable structure 2, and the displacement of the movable structure. The vibration of the movable structure 2 due to waves is approximated as the motion of a spring system. The buoyant force acting on the movable structure 2 (floating body) shown in Figure 11 changes linearly with respect to the displacement of the movable structure 2, similar to the elastic force of a spring. For this reason, in order for the movable structure 2 to vibrate due to waves, the natural frequency of the movable structure 2 and the frequency of the wave must match. As a result, the conditions under which power generation can be performed are limited, and the operating rate may decrease depending on the sea conditions.

[0048] In contrast, the wave power generator 1 can make the vibration system of the movable structure 2 nonlinear by controlling the magnitude of the magnetic attractive force, as shown in Figure 11. By utilizing the vibration of the movable structure 2 (nonlinear vibration phenomenon) in this nonlinearized manner, the frequency band of waves that the movable structure 2 can vibrate can be expanded.

[0049] Furthermore, as shown in Figures 7 and 8, when the movable structure 2 is close to the second position (when the movable structure 2 is vibrating upwards), supplying current to the first coil 54 can move the movable structure 2 downwards. As shown in Figures 9 and 10, when the movable structure 2 is close to the first position (when the movable structure 2 is vibrating downwards), supplying current to the second coil 55 can move the movable structure 2 upwards. By supplying current to the first coil 54 or the second coil 55 at the appropriate timing in this way, the vibration of the movable structure 2 can be increased even when the wave is small and the movable structure 2 is not vibrating easily.

[0050] Figure 12 is a graph showing the relationship between the potential energy of the movable structure 2 and the displacement of the floating body. As described above, by supplying current to the first coil 54 or the second coil 55 at the appropriate timing, the movable structure 2 can be given the energy necessary to overcome the potential barrier. As a result, the movable structure 2 (floating body) can continue to vibrate significantly beyond the potential barrier.

[0051] Furthermore, when the waves are very large, supplying a large current to the first coil 54 or the second coil 55 increases the restraining force due to magnetic attraction, thereby suppressing vibration of the movable structure 2. This prevents damage to the wave power generator 1 when the waves are very large.

[0052] As shown in Figures 4(a) and 4(b) and Figure 5, the first permanent magnet 51 is provided such that in the first state, the magnetic path of the first permanent magnet 51 is a closed magnetic path passing through the magnetic material 53, and the second permanent magnet 52 is provided at a different position in direction D1 from the first permanent magnet 51 such that in the second state, the magnetic path of the second permanent magnet 52 is a closed magnetic path passing through the magnetic material 53. This makes it possible to suitably realize an configuration in which the magnetic path of the first permanent magnet 51 is a closed magnetic path in the first state and the magnetic path of the second permanent magnet 52 is a closed magnetic path in the second state.

[0053] As shown in Figures 2 and 6, the power supply unit 56 controls the current supplied to the first coil 54 or the second coil 55 based on the position information detected by the position sensor 57. In this case, the nonlinearity of the vibration of the movable structure 2 can be appropriately controlled according to the position of the movable structure 2.

[0054] As shown in Figure 2, the armature structure 4 can vibrate along direction D1 due to waves. In this case, the options for locations where the wave power generator 1 can be installed can be increased.

[0055] As shown in Figure 1, the wave power generation system 10 comprises a plurality of wave power generators 1 and an electrical system 11 that exchanges the power generated by each of the plurality of wave power generators 1. In this case, for example, power can be generated efficiently by using the wave power generator 1 that is relatively easy to generate power with depending on the sea conditions. In addition, by supplying power to the wave power generator 1 that is less prone to vibration to induce vibration, power can be generated by the wave power generation system 10 as a whole. Furthermore, even if the connection to the external power grid is cut off, the wave power generation system 10 can still be operated because power can be generated inside the system. [Differentiation]

[0056] This disclosure is not limited to the embodiments described above. For example, the materials and shapes of each component are not limited to those described above, but can be made from a variety of materials and shapes.

[0057] In the above embodiment, the control unit 5 had a first permanent magnet 51, a second permanent magnet 52, and a magnetic material 53. However, as shown in Figures 13(a) to 13(c), the control unit 5 may also have a permanent magnet 61, a first magnetic material 62, and a second magnetic material 63. Figure 13(a) is a cross-sectional view showing a first modified arrangement of the permanent magnet and magnetic material. Figure 13(b) is a cross-sectional view showing the positional relationship of the permanent magnet 61, the first magnetic material 62, and the second magnetic material 63 in the first state. Figure 13(c) is a cross-sectional view showing the positional relationship of the permanent magnet 61, the first magnetic material 62, and the second magnetic material 63 in the second state.

[0058] The permanent magnet 61 has the same configuration as the first permanent magnet 51 and the second permanent magnet 52 and is provided on the movable structure 2. The first magnetic body 62 and the second magnetic body 63 each have the same configuration as the magnetic body 53 and are provided on the armature structure 4. The first magnetic body 62 has a pair of protrusions 62b corresponding to a pair of protrusions 53b. The second magnetic body 63 has a pair of protrusions 63b corresponding to a pair of protrusions 53b. The first magnetic body 62 and the second magnetic body 63 are aligned in direction D1. The second magnetic body 63 is located above the first magnetic body 62. In other words, the second magnetic body 63 is provided at a different position from the first magnetic body 62 in direction D1.

[0059] As shown in Figure 13(b), in the first state, the permanent magnet 61 is located between a pair of protrusions 62b. That is, in the first state, the north and south poles of the permanent magnet 61 face the pair of protrusions 62b, respectively. As shown in Figure 13(c), in the second state, the permanent magnet 61 is located between a pair of protrusions 63b. That is, in the second state, the north and south poles of the permanent magnet 61 face the pair of protrusions 63b, respectively. In the first state, the magnetic path of the permanent magnet 61 is a closed magnetic path passing through the first magnetic material 62. In the second state, the magnetic path of the permanent magnet 61 is a closed magnetic path passing through the second magnetic material 63.

[0060] In the first modified embodiment, the first coil 54 is provided, for example, on the first magnetic material 62. The second coil 55 is provided, for example, on the second magnetic material 63. In this case, the control unit 5 controls the magnitude of the magnetic attractive force between the permanent magnet 61 and the first magnetic material 62 by controlling the current supplied by the power supply unit 56 to the first coil 54. The control unit 5 controls the magnitude of the magnetic attractive force between the permanent magnet 61 and the second magnetic material 63 by controlling the current supplied by the power supply unit 56 to the second coil 55. This first modified embodiment also expands the frequency band of the waves that can generate electricity, similar to the embodiment described above.

[0061] As shown in Figures 14(a) to 14(c), the control unit 5 may have three permanent magnets 71 and two magnetic materials 72. Figure 14(a) is a cross-sectional view showing a second modified arrangement of the permanent magnets and magnetic materials. Figure 14(b) is a cross-sectional view showing the positional relationship of the three permanent magnets 71 and the two magnetic materials 72 in the first state. Figure 14(c) is a cross-sectional view showing the positional relationship of the three permanent magnets 71 and the two magnetic materials 72 in the second state.

[0062] The permanent magnet 71 has the same configuration as the first permanent magnet 51 and the second permanent magnet 52 and is provided on the movable structure 2. The three permanent magnets 71 are aligned in direction D1. The magnetic body 72 is provided on the armature structure 4. The two magnetic bodies 72 are spaced apart and face each other in direction D2. The magnetic body 72 is a C-shaped member that extends along a direction perpendicular to both directions D1 and D2.

[0063] As shown in Figure 14(b), in the first state, the two upper permanent magnets 71A and 71B of the three permanent magnets 71 are located between the two magnetic materials 72. In the first state, the magnetic paths of the permanent magnets 71A and 71B are closed magnetic paths passing through the two magnetic materials 72. As shown in Figure 14(c), in the second state, the two lower permanent magnets 71B and 71C of the three permanent magnets 71 are located between the two magnetic materials 72. In the second state, the magnetic paths of the permanent magnets 71B and 71C are closed magnetic paths passing through the two magnetic materials 72.

[0064] In the second modification, for example, a control coil is provided for each of the three permanent magnets 71. This second modification also allows for an expansion of the frequency band of the waves that can be generated, similar to the embodiment described above.

[0065] As shown in Figures 15(a) to (c), the control unit 5 may have four permanent magnets 81 and a magnetic material 82. Figure 15(a) is a cross-sectional view showing a third modified arrangement of the permanent magnets and magnetic material. Figure 15(b) is a cross-sectional view showing the positional relationship of the four permanent magnets 81 and the magnetic material 82 in the first state. Figure 15(c) is a cross-sectional view showing the positional relationship of the four permanent magnets 81 and the magnetic material 82 in the second state.

[0066] The permanent magnet 81 has the same configuration as the first permanent magnet 51 and the second permanent magnet 52 and is provided on the armature structure 4. Two of the four permanent magnets 81A are spaced apart and facing each other in direction D2. The other two of the four permanent magnets 81B are spaced apart and facing each other in direction D2. The two permanent magnets 81B are located above the two permanent magnets 81A. The magnetic body 82 is provided on the movable structure 2. The magnetic body 82 is a plate-shaped member that extends along a direction perpendicular to both directions D1 and D2.

[0067] As shown in Figure 15(b), in the first state, the magnetic material 82 is located between the two permanent magnets 81A. In the first state, the magnetic path of each of the two permanent magnets 81A becomes a closed magnetic path passing through the magnetic material 82. As shown in Figure 15(c), the magnetic material 82 is located between the two permanent magnets 81B. In the second state, the magnetic path of each of the two permanent magnets 81B becomes a closed magnetic path passing through the magnetic material 82.

[0068] In the third modification, for example, a control coil is provided for each of the four permanent magnets 81. This third modification also allows for an expansion of the frequency band of the waves that can be generated, similar to the embodiment described above.

[0069] The wave power generator 1 according to the above embodiment had an armature structure 4 that could vibrate along direction D1 due to waves. However, as shown in Figure 16, the armature structure 4 of the modified wave power generator 1A may be fixed to a quay W (fixed structure) on land. Figure 16 is a side view of the modified wave power generator 1A as seen from the side. Note that the first coil 54 and the second coil 55 are not shown in Figure 16. Even with such a modification, the frequency band of waves that can be generated can be expanded, similar to the above embodiment. Furthermore, the stability of the armature structure 4 can be ensured.

[0070] In the above embodiment, a permanent magnet 3 was used as the power generation field and the first permanent magnet 51 and the second permanent magnet 52 were used as the control field. However, electromagnets may be used as both the power generation field and the control field. [Explanation of symbols]

[0071] 1,1A...Wave power generator, 2...Movable structure, 3...Permanent magnet (power generation field section), 4...Armature structure, 5...Control unit, 10...Wave power generation system, 11...Electrical system, 41a,41b,41c...Coil (power generation coil), 51...First permanent magnet (first field section), 52...Second permanent magnet (second field section), 53,72,82...Magnetic material, 54...First coil (control coil), 55...Second coil (control coil), 56,56A,56B...Power supply unit, 57...Position sensor (sensor), 61,71,71A,71B,71C,81,81A,81B...Permanent magnet, 62...First magnetic material, 63...Second magnetic material, D1...Direction (vibration direction), M1...Magnetic path, W...Quay (fixed structure).

Claims

1. A movable structure that can vibrate by waves, The aforementioned movable structure includes a field section for power generation, An armature structure having a power generation coil, wherein an induced electromotive force is generated by a change in the magnetic flux of the power generation field that penetrates the power generation coil, It comprises a control unit and, The control unit, A control field section provided on one of the movable structure and the armature structure, A magnetic material provided on the other side of the movable structure and the armature structure, A control coil provided in either the control field section or the magnetic material, It includes a power supply unit that supplies current to the control coil, The magnetic path of the control field section becomes a closed magnetic path passing through the magnetic material in a first state where the position of the movable structure in the vibration direction of the armature structure is a first position, and becomes a closed magnetic path passing through the magnetic material in a second state where the position of the movable structure in the vibration direction of the armature structure is a second position different from the first position. The control unit controls the magnitude of the magnetic attraction force between the control field unit and the magnetic material by controlling the current supplied by the power supply unit to the control coil, thereby controlling the magnitude of the magnetic attraction force between the control field unit and the magnetic material, in a wave power generator.

2. The control field section has a first field section and a second field section. The first field section is provided such that, in the first state, the magnetic path of the first field section becomes a closed magnetic path passing through the magnetic material. The wave power generator according to claim 1, wherein the second field section is provided at a position different from that of the first field section in the direction of vibration such that, in the second state, the magnetic path of the second field section becomes a closed magnetic path passing through the magnetic material.

3. The control coil has a first coil and a second coil provided in the first field section and the second field section, respectively. The control unit controls the magnitude of the magnetic attractive force between the first field section and the magnetic material by controlling the current supplied by the power supply unit to the first coil. The wave power generator according to claim 2, wherein the control unit controls the magnitude of the magnetic attractive force between the second field and the magnetic material by controlling the current supplied by the power supply unit to the second coil.

4. The magnetic material comprises a first magnetic material and a second magnetic material. The first magnetic material is provided such that, in the first state, the magnetic path of the control field section becomes a closed magnetic path passing through the first magnetic material. The wave power generator according to claim 1, wherein the second magnetic material is provided at a position different from the first magnetic material in the direction of vibration such that, in the second state, the magnetic path of the control field section becomes a closed magnetic path passing through the second magnetic material.

5. The control coil has a first coil and a second coil provided on the first magnetic material and the second magnetic material, respectively. The control unit controls the magnitude of the magnetic attraction force between the control field unit and the first magnetic material by controlling the current supplied by the power supply unit to the first coil. The wave power generator according to claim 4, wherein the control unit controls the magnitude of the magnetic attraction force between the control field unit and the second magnetic material by controlling the current supplied by the power supply unit to the second coil.

6. The control unit has a sensor for detecting position information indicating the position of the movable structure in the vibration direction relative to the armature structure, The wave power generator according to claim 1, wherein the power supply unit controls the current supplied to the control coil based on the position information.

7. The wave power generator according to claim 1, wherein the armature structure is capable of vibrating along the direction of vibration due to waves.

8. The wave power generator according to claim 1, wherein the armature structure is fixed to a fixed structure on land.

9. A plurality of wave power generators, each of which is a wave power generator according to claim 1, A wave power generation system comprising: an electrical system for receiving and transmitting electricity generated by each of the aforementioned plurality of wave power generators.

Images