JP2014214600A - Ocean current power generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underwater floating ocean current power generation device whose attitude can be quickly controlled in a simple construction.SOLUTION: With the control operation of a control part (20), water is poured into or drained from a right front ballast tank (10) and a left front ballast tank (12) and water is drained from or poured into a right rear ballast tank (11) and a left rear ballast tank (13) so that a whole pod is tilted frontward or rearward, and water is poured into or drained from a center right ballast tank (14) and water is drained from or poured into a center left ballast tank (15) so that the whole pod is tilted to the right or left side.

Description

  The present invention relates to a submerged floating ocean current power generator capable of floating and sinking a pod including a turbine and a generator, and more particularly to a posture control technique of the ocean current power generator.

2. Description of the Related Art In recent years, ocean current power generation apparatuses that generate power using the energy of seawater flow such as ocean currents and tidal currents have been developed.
In general, an ocean current power generation apparatus arranges a turbine that rotates in response to the flow of seawater, and generates electricity by driving a generator by the rotation. Examples of the turbine include a horizontal axis turbine whose rotation axis is parallel (horizontal) to the flow of seawater, and a vertical turbine whose rotation axis is perpendicular to the flow of seawater.

  For example, in an ocean current power generation device for a horizontal axis turbine, in a foundation structure that stays at a predetermined water depth position by a buoyancy adjusting means, a rope is used to control the attitude of the foundation structure according to the direction of underwater flow. A moored configuration is disclosed (see Patent Document 1). As described above, the ocean current power generation device of Patent Document 1 is a so-called underwater floating type in which a pod (foundation structure) provided with a turbine and a power generation device is completely submerged in seawater, and the pod is moored and suspended from the seabed. The ocean current power generator.

JP 2001-248532 A

In the case of an underwater floating type ocean current power generation device as described in Patent Document 1, the posture of the pod in the yaw direction is directed in a direction opposite to the flow of seawater by being moored by a mooring line. However, the postures in the pitching direction and the rolling direction cannot be easily controlled.
Therefore, in the ocean current power generation device described in Patent Document 1, an attitude control blade is provided at the tip of the pod, and the attitude in the pitching direction is controlled by the attitude control blade.

However, the attitude control by such attitude control blades is complicated because the responsiveness changes depending on the strength of the seawater flow. In particular, when the flow of seawater is low, the responsiveness deteriorates, and there is also a problem that posture control cannot be performed promptly.
Further, in the ocean current power generation device described in Patent Document 1, consideration is not given to the posture control in the rolling direction of the pod, and it cannot cope with the posture change in the rolling direction.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide an ocean current power generator capable of quickly controlling the posture with a simple configuration in a submerged floating ocean current power generator. Is to provide.

  In order to achieve the above object, in the ocean current power generation device according to claim 1, a turbine that rotates by the flow of seawater, and a pod that supports the turbine and houses a power generation unit that generates power by the rotation of the turbine. In the submerged floating ocean current power generation apparatus, the buoyancy changing means arranged in a part of the pod and changing the buoyancy of the arrangement part, and the buoyancy changing means changing the buoyancy of a part of the pod. And a posture control unit for controlling the posture of the pod.

In the ocean current power generation device of claim 2, in claim 1, the buoyancy change means is provided on at least one of the upstream side and the downstream side with respect to the flow of the seawater in the pod, and the attitude control unit is The buoyancy change means changes the buoyancy of a part of the pod to control the attitude of the pod in the pitching direction.
According to a third aspect of the ocean current power generation device of the first or second aspect, the pair of left and right pods are connected via a connecting portion, and the buoyancy change means is provided on at least one of the pair of left and right pods. The attitude control unit controls the attitude of the entire pod including the pod and the connecting part in the rolling direction by changing the buoyancy of a part of the pod by the buoyancy changing means.

The ocean current power generation device according to claim 4 is characterized in that, in any one of claims 1 to 3, the buoyancy changing means is a ballast tank that changes buoyancy by pouring or draining water.
In the ocean current power generation device according to claim 5, in any one of claims 1 to 3, the buoyancy changing means is a volume increasing / decreasing unit that changes buoyancy by increasing / decreasing the volume with respect to the pod. It is said.

  In the ocean current power generation device according to claim 6, in any one of claims 1 to 3, the buoyancy change means is a drag generation unit that changes buoyancy by generating a drag in response to the flow of seawater. It is characterized by.

According to the present invention using the above means, the attitude of the pod is controlled using the buoyancy changing means that is arranged in a part of the pod and changes the buoyancy of the arrangement part in the submerged floating current generator.
In this way, by partially changing the buoyancy of the pod and controlling the posture of the pod, the posture can be quickly controlled with a simple configuration and easy control.

1 is an overall configuration diagram of an ocean current power generation device according to a first embodiment of the present invention. It is explanatory drawing about the attitude | position control of the pod which concerns on 1st Embodiment of this invention. It is explanatory drawing (a) (b) about attitude | position control of the pod of the ocean current electric power generating apparatus which concerns on 2nd Embodiment. It is explanatory drawing (a) about the attitude | position control of the pod of the ocean current electric power generating apparatus which concerns on 3rd Embodiment, and its modification (b).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Referring to FIG. 1, there is shown an overall configuration diagram of an ocean current power generation device according to a first embodiment of the present invention.
As shown in FIG. 1, in the ocean current power generation device 1, a pair of left and right pods 2, 2 are connected by a connecting beam 3 (connecting portion), and turbines 4, 4 are provided at the tail of each pod 2, 2. This is a so-called twin-current ocean current generator.

In the turbine 4, two blades 6, 6 extend from a hub portion 5 at the center of rotation in directions opposite to each other perpendicular to the rotation axis direction. The turbines 4, 4 provided in the pair of left and right pods 2, 2 are opposite in rotation direction and counter-rotate to cancel the rotational torque accompanying the rotation of both turbines 4, 4.
One end of a mooring line 7 is connected to the center part of the lower surface of each pod 2, and each mooring line 7 joins in the middle to form a Y-shape as a whole. The other end of the mooring line 7 is a sinker 8. It is connected to the. The sinker 8 is fixed to the seabed, and moors the pods 2 and 2 via a mooring line 7. Although not shown, a power transmission cable extends from each of the pods 2 and 2 in parallel with the mooring cable 7, and the power transmission cable is connected to a transformer provided on the seabed.

Thus, the pods 2 and 2 moored via the mooring line 7 float in the water in a posture opposite to the flow direction of the seawater (floating and sinking in parallel with the flow of the seawater). That is, the posture of the pods 2 and 2 in the yaw direction is determined by the flow direction of the seawater.
Although not shown, various devices such as a generator (power generation unit) that generates electric power by rotating the turbines 4 and 4 are accommodated in the pods 2 and 2.

  The ocean current power generation apparatus 1 configured as described above generates power by the generator when the turbine 4 rotates in response to the flow of seawater caused by the ocean current. As the pod 2 rotates, the mooring line 7 is stretched when the turbine 4 rotates and thrust is generated downstream of the seawater. If the strength of the seawater flow is weak, the rotational speed of the turbine 4 is low and the pod 2 floats at a shallow water depth. . On the other hand, when the strength of the seawater flow increases, the rotational speed of the turbine 4 increases and the thrust also increases. Therefore, the pod 2 moves downstream with the connecting portion of the mooring line 7 and sinker 8 as a fulcrum and sinks. However, it will float at a deep water depth.

Next, referring to FIG. 2, there is shown an explanatory view of the attitude control of the pod in the ocean current power generation device according to the first embodiment, which will be described below with reference to FIG. In the following description, the upstream side is the front and the downstream side is the rear along the flow direction of the seawater, and the horizontal and vertical direction is the left-right direction with respect to the flow direction.
As shown in FIG. 2, each pod 2, 2 is provided with ballast tanks (buoyancy changing means) 10 to 13 on the front side and the rear side. Here, the right front ballast tank 10, the right rear ballast tank 11, the left front ballast tank 12, and the left rear ballast tank 13 are also referred to corresponding to the respective arrangement positions.

Ballast tanks 14 and 15 (buoyancy change means) are also provided on the left and right sides of the connecting beam 3, which are also referred to as a center right ballast tank 14 and a center left ballast tank 15.
Each of the ballast tanks 10 to 15 is provided with a pump or the like (not shown) for pouring and draining seawater, and seawater can be individually poured and drained. Each ballast tank 10-15 changes the buoyancy of an arrangement | positioning part by the pouring / draining of the said seawater. Specifically, each ballast tank 10-15 reduces the buoyancy of the arrangement | positioning part by pouring water, and increases the buoyancy of an arrangement | positioning part by draining.

The pouring / draining of each of the ballast tanks 10 to 15 is controlled by a control unit 20 (attitude control unit) provided inside or outside the pods 2 and 2.
The controller 20 controls the attitude of the entire pod including the pods 2 and 2 and the connecting beam 3 by changing the buoyancy by pouring and draining the ballast tanks 10 to 15.
The controller 20, for example, drains the right rear ballast tank 11 and the left rear ballast tank 13 together with the water injection of the right front ballast tank 10 and the left front ballast tank 12, thereby reducing the buoyancy of the front side as a whole pod and the rear side ballast tank 13. It is possible to increase the buoyancy and tilt the entire pod forward.

  Conversely, the control unit 20 increases the buoyancy on the front side of the pod as a whole by pouring the right rear ballast tank 11 and the left rear ballast tank 13 together with the drainage of the right front ballast tank 10 and the left front ballast tank 12. It is possible to tilt the entire pod backwards by reducing the buoyancy on the side. It is also possible to perform similar posture control by pouring / draining only one of the front ballast tanks 10 and 12 and the rear ballast tanks 11 and 13.

In this way, the control unit 20 performs posture control in the pitching direction of the entire pod by causing a buoyancy difference relatively before and after the entire pod.
Further, the control unit 20 drains the central left ballast tank 15 together with, for example, water injection of the central right ballast tank 14, thereby reducing the buoyancy on the right side and increasing the buoyancy on the left side as a whole pod. It can be tilted to the right.

  On the contrary, the control unit 20 performs the water injection of the central left ballast tank 15 together with the drainage of the central right ballast tank 14, thereby increasing the right buoyancy and decreasing the left buoyancy as a whole pod. It can be tilted to the left. It is also possible to perform similar posture control by pouring and draining only one of the center right ballast tank 14 and the center left ballast tank 15. Alternatively, the same posture control can be performed by pouring and draining the ballast tanks 10 to 13 provided in the pods 2 and 2. Furthermore, the same attitude control can be performed by pouring and draining the ballast tanks 10 to 15 in the pods 2 and 2 and the connecting beam 3 in combination.

In this way, the control unit 20 controls the posture of the entire pod in the rolling direction by causing a relative buoyancy difference between the left and right of the entire pod.
The control unit 20 can keep the posture of the entire pod horizontal or tilt by performing appropriate drainage of the ballast tanks 10 to 15 according to the posture change of the entire pod. In addition, the control part 20 injects water about all the ballast tanks 10-15, or only the ballast tanks 10-13 in the pods 2 and 2 only, or only the ballast tanks 14 and 15 in the connection beam 3, and the whole pod. Can be levitated, and the entire pod can be allowed to sink by draining at the same time.

  The ocean current power generation device 1 according to the first embodiment partially changes the buoyancy by pouring and draining the ballast tanks 10 to 15 disposed in each part of the pods 2 and 2 and the connecting beam 3 under the control of the control unit 20. To control the attitude of the entire pod. Thus, the ballast tanks 10 to 15 originally provided for adjusting the buoyancy of the entire pod are easily provided with the front, rear, left and right parts, and the ballast tanks 10 to 15 of the respective parts are relatively poured and drained. The attitude of the entire pod can be controlled by the control.

The buoyancy change by the ballast tanks 10 to 15 does not depend on the strength of the seawater flow, and the buoyancy can be quickly changed by pouring / draining, so that the responsiveness of the posture control can be improved.
Although the description of the first embodiment of the ocean current power generation apparatus according to the present invention has been completed above, the first embodiment is not limited to the above configuration.

  In the above-described embodiment, the ballast tanks 10 to 15 are disposed inside the pods 2 and 2 and the connecting beam 3, respectively, but the position and number of the ballast tanks are not limited thereto. For example, it is good also as a structure which provided the ballast tank only in the inside of a pod, or only in a connection beam. Further, a configuration in which the ballast tank is provided only in one of the pair of left and right pods, or a configuration in which the ballast tank is provided only on the front side or the rear side of each of the pair of left and right pods may be used. A ballast tank may be provided at a position where a buoyancy difference can be relatively generated.

  Moreover, in the said 1st Embodiment, although it is the structure which connected the center part of the left-right paired pods 2 and 2 by the one connection beam 3, the front side of each pod is a front side connection beam, and the rear side is a rear side connection beam. It is good also as a structure which has two connection beams connected by these. In this case, by providing ballast tanks in the front and rear connection beams, the posture control of the entire pod in the pitching direction can be performed also by pouring and draining the ballast tanks in the connection beams.

Next, a second embodiment of the present invention will be described.
Referring to FIG. 3, there are shown explanatory diagrams (a) and (b) regarding the attitude control of the pod of the ocean current power generation device according to the second embodiment. Note that, in the ocean current power generation device according to the second embodiment, the same reference numerals are given to the same configurations as those of the first embodiment, and detailed description thereof is omitted.

The ocean current power generation device 30 in the second embodiment is the same in basic configuration as the ocean current power generation device 1 in the first embodiment shown in FIG. 1, and in FIGS. Only one of the pods 2 is shown. The other pod 2 has the same configuration, and the description of the other pod 2 is omitted.
As shown in FIGS. 3A and 3B, the ocean current power generation apparatus 30 according to the second embodiment is provided with volume increasing / decreasing units 31 and 32 (buoyancy change means) on the front side and the rear side of the pod 2. Here, it is also referred to as a front volume increasing / decreasing unit 31 and a rear volume increasing / decreasing unit 32 corresponding to each arrangement position.

  Each volume increase / decrease part 31 and 32 is comprised from rod 31a, 32a and accommodating part 31b, 32b. The rods 31a and 32a have a columnar shape extending in the front-rear direction of the pod 2 and are slidable by actuators (not shown) in the bottomed cylindrical accommodating portions 31b and 32b opened on one side. Each of the volume increasing / decreasing units 31 and 32 is configured to increase or decrease the volume of the pod 2 by projecting or storing the rods 31 a and 32 a from the surface of the pod 2 to change the buoyancy of the arrangement portion. Specifically, each of the volume increasing / decreasing units 31 and 32 increases the buoyancy of the arrangement part by projecting the rods 31a and 32a to increase the volume of the arrangement part. On the contrary, the rods 31a and 32a are accommodated in the accommodating portions 31b and 32b to reduce the volume, thereby reducing the buoyancy of the arrangement portion.

Protrusion and storage of the rods 31a and 32a in the volume increasing / decreasing units 31 and 32 are controlled by a control unit 33 (attitude control unit) provided inside or outside the pod 2.
The control unit 33 controls the posture of the entire pod including the pods 2 and 2 and the connecting beam 3 by changing the buoyancy by projecting or storing the rods 31a and 32a of the volume increasing / decreasing units 31 and 32. is there.

For example, as shown in FIG. 3A, the control unit 33 projects the rod 31a of the front volume increasing / decreasing unit 31 in each of the left and right pods 2 and houses the rod 32a of the rear volume increasing / decreasing unit 32. It is possible to tilt the entire pod backward by increasing the buoyancy on the front side of the entire pod and decreasing the buoyancy on the rear side.
Conversely, as shown in FIG. 3B, the control unit 33 houses the rod 31a of the front volume increasing / decreasing unit 31 in each of the left and right pods 2 and projects the rod 32a of the rear volume increasing / decreasing unit 32. Thus, it is possible to tilt the entire pod forward by reducing the buoyancy on the front side and increasing the buoyancy on the rear side of the pod as a whole.

In this way, the control unit 33 performs posture control in the pitching direction of the entire pod by causing a buoyancy difference relatively before and after the entire pod.
In addition, the control unit 31 houses the front and rear volume increase / decrease units 31 and 32 provided in the right pod 2 and the front and rear volume increase / decrease units 31 provided in the left pod 2. , 32 can be tilted to the right side by reducing the right side buoyancy and increasing the left side buoyancy as a whole pod.

Conversely, the control unit 33 projects the rods 31 a and 32 a of the front and rear volume increasing / decreasing units 31 and 32 provided on the right pod 2, and the front and rear volume increasing and decreasing unit 31 provided on the left pod 2. , 32 can be tilted to the left side by increasing the buoyancy on the right side and decreasing the buoyancy on the left side as a whole pod.
In this manner, the control unit 33 controls the posture of the entire pod in the rolling direction by causing a relative buoyancy difference between the left and right of the entire pod.

  The control unit 33 keeps the posture of the entire pod horizontal or tilts it by projecting or storing the rods 31a, 32a of the volume increasing / decreasing units 31, 32 according to the posture change of the entire pod. Can do. In addition, the control part 33 can make the whole pod float by projecting all the volume increase / decrease parts 31 and 32 in the pair of left and right pods 2 and 2 at the same time. it can.

  Under the control of the control unit 33, the ocean current power generation device 30 in the second embodiment changes the buoyancy by projecting or storing the rods 31a, 32a of the volume increasing / decreasing units 31, 32 disposed in the respective parts of the pods 2, 2. To control the attitude of the entire pod. The volume increasing / decreasing units 31 and 32 are simply configured to project or store the rods 31a and 32a with respect to the pod 2, and the entire pod can be easily controlled by relatively projecting or storing the rods 31a and 32a of each unit. Can be controlled.

The buoyancy change by the volume increasing / decreasing units 31 and 32 does not depend on the strength of the seawater flow, and the buoyancy can be quickly changed by the protrusion or storage of the rods 31a and 32a. Can be improved.
Although the description of the second embodiment of the ocean current power generation device according to the present invention has been completed above, the second embodiment is not limited to the above configuration.

  In the ocean current power generation apparatus 30 according to the second embodiment, the volume increasing / decreasing units 31 and 32 are disposed before and after the pods 2 and 2, but the position and number of the volume increasing / decreasing units are not limited to this. Absent. For example, a volume increase / decrease part may be provided in the connection beam. Moreover, the structure which provided the volume increasing / decreasing part only in one of the pair of left and right pods, the structure having the volume increasing / decreasing part only on the front side or the rear side of the pair of left and right pods, etc. A volume increasing / decreasing portion may be provided at a position where a buoyancy difference can be relatively generated.

  Moreover, in 2nd Embodiment, the volume increase / decrease part 31 and 32 is comprised from rod 31a, 32a and accommodating part 31b, 32b, and the said rod 31a, 32a slides in the front-back direction, Any structure that can increase or decrease the volume of the pod is acceptable, and the mechanism for increasing or decreasing the shape or volume of the rod is not limited thereto.

Next, a third embodiment of the present invention will be described.
Referring to FIG. 4, there are shown an explanatory diagram (a) about the attitude control of the pod in the ocean current power generation device according to the third embodiment and a modification (b) thereof. Note that, in the ocean current power generation device according to the third embodiment, the same reference numerals are given to the same configurations as those of the first embodiment, and detailed description thereof is omitted.

The ocean current power generation device 40 according to the third embodiment has the same basic configuration as the ocean current power generation device 1 according to the first embodiment shown in FIG.
As shown in FIG. 4 (a), the ocean current power generation device 40 according to the third embodiment has resistance plates (buoyancy change means, drag generation portion) 41a on the front and rear upper and lower surfaces of the left and right pods 2,2. , 41b to 44a, 44b are disposed. Here, the upper right front resistor plate 41a, the lower right front resistor plate 41b, the upper right rear resistor plate 42a, the lower right rear resistor plate 42b, the upper left front resistor plate 43a, the lower left front resistor plate 43b, Also referred to as the upper left rear resistor plate 44a and the lower left rear resistor plate 44b.

  Each of the resistance plates 41a, 41b to 44a, 44b is a plate material whose front end portions are rotatably attached to the pods 2, 2. Each of the resistance plates 41a, 41b to 44a, 44b is developed by using a front end portion as a fulcrum by an actuator (not shown) and generating a drag by receiving a flow of seawater on the plate surface, thereby changing the buoyancy of the arrangement portion. is there. Specifically, the resistance plates 41a to 44a provided on the upper surfaces of the pods 2 and 2 are unfolded and receive a flow of seawater, thereby generating a downward drag and buoyancy of the arrangement portion. Reduce. Conversely, each of the resistance plates 41b to 44b provided on the lower surfaces of the pods 2 and 2 expands and receives a flow of seawater, thereby generating an upward drag and increasing the buoyancy of the arrangement portion. .

The development of each of the resistance plates 41a, 41b to 44a, 44b is controlled by a control unit (posture control unit) provided inside or outside the pods 2, 2 although not shown.
The control unit controls the attitude of the entire pod by changing the buoyancy by deploying each of the resistance plates 41a, 41b to 44a, 44b.
For example, as shown in FIG. 4A, the control unit expands the lower right rear resistance plate 42b and expands the upper left front resistance plate 43a, thereby increasing the right rear side buoyancy of the entire pod and moving the left front By reducing the buoyancy on the side, the entire pod can be tilted forward and tilted to the left.

In this way, the control unit performs posture control in the pitching direction and the rolling direction of the entire pod by causing a relative difference in buoyancy between the front, rear, left and right of the entire pod.
The control unit can keep the posture of the entire pod horizontal or tilt by deploying appropriate resistance plates 41a, 41b to 44a, 44b according to the posture change of the entire pod. The control unit can lift the entire pod by simultaneously deploying all the resistance plates 41b to 44b on the lower surface side of the pods 2 and 2, and all the resistances on the upper surface side of the pods 2 and 2 can be lifted. The whole pod can also be settled by deploying the plates 41a to 44a simultaneously.

  The ocean current power generation device 40 according to the third embodiment changes the buoyancy by expanding the resistance plates 41a, 41b to 44a, 44b disposed in the respective parts of the pods 2 and 2 under the control of the control unit. The overall attitude is controlled. The resistance plates 41a, 41b to 44a, 44b are simply configured to be deployed with respect to the pod 2, and the resistance plate 41a, 41b to 44a, 44b of each part is relatively controlled so that the entire pod can be controlled. The attitude can be controlled.

  The buoyancy change by the resistance plates 41a, 41b to 44a, 44b can generate a drag efficiently by receiving the flow of seawater over the entire plate surface, and can quickly change the buoyancy. In particular, in the present embodiment, the resistance plates 41a, 41b to 44a, 44b are provided on the pods 2 and 2 that are largely separated from each other on the left and right, so that a drag difference between the pods can be easily generated, and free. Attitude control can be realized.

Although the description of the third embodiment of the ocean current power generation device according to the present invention has been completed above, the third embodiment is not limited to the above configuration.
In the ocean current power generation device 40 of the third embodiment, the resistance plates 41a, 41b to 44a, 44b are arranged on the front and rear upper and lower surfaces of each pod 2, 2, but the positions where the resistance plates are arranged. And the number is not limited to this. For example, a configuration may be adopted in which resistance plates 51a to 54a are provided on the upper and lower surfaces of the connection beam 3 as in the ocean current power generation device 50 in the modification of the third embodiment shown in FIG. 4B (FIG. 3B). The resistor plate on the lower surface of the connecting beam is not shown). Even with such a configuration, the same effects as those of the third embodiment can be obtained.

Further, a configuration in which a resistance plate is provided only on one of the pair of left and right pods or a configuration in which a resistance plate is provided only on the front side or the rear side of the pair of left and right pods may be used. What is necessary is just to provide a resistance board in the position which can produce a buoyancy difference relatively.
Further, in the third embodiment, the resistance plates 41a, 41b to 44a, 44b are plate members whose front ends are pivotally attached to the pods 2, 2, but the resistance plate may have a structure capable of causing a drag force. What is necessary is not limited to this. For example, the rear end portion of the resistance plate may be rotatably attached to the pod.

1, 30, 40, 50 Ocean current power generation equipment 2 Pod 3 Connection beam (connection part)
10-15 Ballast tank (buoyancy change means)
20, 33 Control unit (attitude control unit)
31, 32 Volume increase / decrease part (buoyancy change means)
31a, 32a Rod 31b, 32b Storage part 41a, 41b-44a, 44b Resistance plate (buoyancy change means, drag generation part)

Claims (6)

A turbine that rotates by the flow of seawater;
In a submerged floating ocean current power generation apparatus that includes the pod that supports the turbine and that houses a power generation unit that generates power by rotation of the turbine,
A buoyancy changing means disposed in a part of the pod and changing the buoyancy of the arrangement part;
A posture control unit for controlling the posture of the pod by changing the buoyancy of a part of the pod by the buoyancy change means;
An ocean current power generation device comprising: The buoyancy changing means is provided on at least one of the upstream side and the downstream side with respect to the flow of the seawater in the pod,
The ocean current power generation apparatus according to claim 1, wherein the attitude control unit controls the attitude of the pod in the pitching direction by changing the buoyancy of a part of the pod by the buoyancy change unit. A pair of left and right pods are connected via a connecting portion;
The buoyancy changing means is provided on at least one of the pair of left and right pods,
The posture control unit controls a posture in a rolling direction of the entire pod including the pod and the connecting portion by changing a buoyancy of a part of the pod by the buoyancy changing unit. The ocean current power generation device according to 2.   4. The ocean current power generation apparatus according to claim 1, wherein the buoyancy changing unit is a ballast tank that changes buoyancy by pouring or draining water. 5.   4. The ocean current power generation apparatus according to claim 1, wherein the buoyancy changing unit is a volume increasing / decreasing unit that changes buoyancy by increasing / decreasing the volume of the pod. 5.   4. The ocean current power generation apparatus according to claim 1, wherein the buoyancy change unit is a drag generation unit that changes a buoyancy by generating a drag in response to the flow of the seawater. 5.

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