JP6988609B2 - Control device, water flow power generation system, and control method of water flow power generation device - Google Patents

Description

The present invention relates to a control device, a water flow power generation system, and a control method for the water flow power generation device.

A water flow power generation device that is installed in water such as the sea and generates power by using the flow of water is known. For example, Patent Document 1 describes a diving platform (water flow generator) including two power pods. In the water flow power generation device described in Patent Document 1, a rotor assembly that is rotated by the flow of water is provided at the end of each power pod. The rotor assembly includes a rotor blade (blade), and inside each power pod is provided with a generator that generates electric power by rotating the rotor assembly. The two power pods are connected by a wing (connecting part) as a transverse structure.

Special Table 2014-543375 Gazette

In the water flow power generation device as described above, the water flow power generation device may be installed so that one end of both ends of the power pod provided with the rotor assembly is located downstream. In this case, a region where the flow velocity decreases (a region where the flow velocity decreases) is generated behind the connecting portion when viewed from the upstream. While the blade passes through such a flow velocity reduction region, the force applied to the blade due to the flow of water decreases as compared with the case where the blade is located outside the flow velocity reduction region, so that the power generated by the generator fluctuates (decreases). )do. Therefore, when the electric power generated from each generator is combined and output as output electric power to the external power system, if the blades of the two power pods pass through the flow velocity decrease region at the same timing, The fluctuation range of output power may increase.

The present invention provides a control device, a water flow power generation system, and a control method for the water flow power generation device capable of reducing the fluctuation range of the output power.

The control device according to one aspect of the present invention includes a first blade that rotates around a first rotation axis, a first generator that generates a first electric power based on the rotation of the first blade, a first blade, and a first power generation. The first pod on which the machine is installed, the second blade that rotates around the second rotation axis, the second generator that generates the second power based on the rotation of the second blade, and the second blade and the second generator It is a control device for controlling a water current power generation device including a second pod provided and a connecting portion connecting the first pod and the second pod. The region in which the first blade rotates when viewed from the direction in which the first rotation axis extends includes the first region in which the first blade overlaps the connecting portion, and the region in which the second blade rotates when viewed from the direction in which the second rotation shaft extends. Includes a second region where the second blade overlaps the connection. The control device has a first rotation speed of the first blade and a second rotation speed of the second blade so that the timing at which the first blade passes through the first region and the timing at which the second blade passes through the second region are different from each other. To control.

In this control device, the timing at which the first blade passes through the first region where the first blade overlaps the connecting portion and the timing at which the second blade passes through the second region where the second blade overlaps the connecting portion are different from each other. The first rotation speed of the first blade and the second rotation speed of the second blade are controlled. Therefore, the possibility that the first blade and the second blade overlap the connecting portion at the same timing is reduced. As a result, the fluctuation range of the output power obtained by combining the first power generated based on the rotation of the first blade and the second power generated based on the rotation of the second blade is the first power and the second power, respectively. It is almost equal to the fluctuation range. As a result, it is possible to reduce the fluctuation range of the output power.

The control device may acquire the first rotation angle of the first blade with respect to the first blade when it is located in the first region, and the control device may acquire the first rotation angle with reference to the second blade when it is located in the second region. The second rotation angle of the two blades may be acquired. When the phase difference, which is the difference between the first rotation angle and the second rotation angle, becomes smaller than a predetermined threshold value, the control device sets the first rotation speed or the first rotation speed so that the phase difference becomes larger than the threshold value. Two rotation speeds may be set.

The smaller the phase difference, which is the difference between the first rotation angle of the first blade and the second rotation angle of the second blade, the shorter the time interval between the timings at which the first blade and the second blade each overlap the connecting portion. .. In the above configuration, the first rotation speed or the second rotation speed is set so that the phase difference becomes larger than the threshold value even if the phase difference becomes smaller than the threshold value. That is, even if the time interval between the timings at which the first blade and the second blade overlap each other on the connecting portion is shortened, the phase difference gradually increases and the phase difference becomes larger than the threshold value. As a result, the timing at which the first blade overlaps the connecting portion and the timing at which the second blade overlaps the connecting portion are maintained in different states. As a result, it is possible to reduce the fluctuation range of the output power.

When the phase difference is larger than the threshold value, the control device sets the first rotation speed and the second rotation speed to normal values which are the same values as each other according to the flow velocity detected by the flow velocity detection unit provided in the water flow power generation device. It may be set. The control device may set the first rotation speed or the second rotation speed so that the first rotation speed and the second rotation speed are different from each other when the phase difference becomes smaller than the threshold value.

In the above configuration, when the phase difference is larger than the threshold value, the first blade and the second blade rotate at a normal value rotation speed according to the flow velocity. When the phase difference becomes smaller than the threshold value, the first rotation speed of the first blade and the second rotation speed of the second blade are set to different values. Therefore, since the rotation speeds are different from each other, the phase difference, which is the difference between the first rotation angle and the second rotation angle, becomes large, and the phase difference becomes larger than the threshold value. This prevents the first blade and the second blade from overlapping the connecting portion at the same timing. As a result, it is possible to efficiently generate the first power and the second power while reducing the fluctuation range of the output power.

A water flow power generation system according to another aspect of the present invention includes a water flow power generation device and a control device for controlling the water flow power generation device. The water flow power generator includes a first blade that rotates around the first rotation axis, a first generator that generates first electric power based on the rotation of the first blade, and a first blade and a first generator. A pod, a second blade that rotates around a second rotation axis, a second generator that generates a second electric power based on the rotation of the second blade, and a second pod provided with a second blade and a second generator. , A connecting portion that connects the first pod and the second pod. The region in which the first blade rotates when viewed from the direction in which the first rotation axis extends includes the first region in which the first blade overlaps the connecting portion, and the region in which the second blade rotates when viewed from the direction in which the second rotation shaft extends. Includes a second region where the second blade overlaps the connection. The control device has a first rotation speed of the first blade and a second rotation speed of the second blade so that the timing at which the first blade passes through the first region and the timing at which the second blade passes through the second region are different from each other. To control.

In this water flow power generation system, the timing at which the first blade passes through the first region where the first blade overlaps the connecting portion and the timing at which the second blade passes through the second region where the second blade overlaps the connecting portion are different from each other. The first rotation speed of the first blade and the second rotation speed of the second blade are controlled. Therefore, the possibility that the first blade and the second blade overlap the connecting portion at the same timing is reduced. As a result, the fluctuation range of the output power obtained by combining the first power generated based on the rotation of the first blade and the second power generated based on the rotation of the second blade is the first power and the second power, respectively. It is almost equal to the fluctuation range. As a result, it is possible to reduce the fluctuation range of the output power.

The first blade and the second blade may rotate in opposite directions to each other.

In this case, the torques generated by the rotation of the first blade and the second blade are opposite to each other, so that the posture of the water flow power generator can be stabilized.

The water flow power generation device may output the output power obtained by synthesizing the first power and the second power to the outside.

In this case, the number of cables for sending the electric power generated in the water current power generation device from the water flow power generation device to the outside can be reduced as compared with the case where the first electric power and the second electric power are sent respectively. As a result, it is possible to simplify the cable installation work underwater.

The control method of the water flow power generation device according to still another aspect of the present invention includes a first blade that rotates around the first rotation axis, a first generator that generates a first electric power based on the rotation of the first blade, and a first. A first pod provided with one blade and a first generator, a second blade that rotates around a second rotation axis, a second generator that generates second power based on the rotation of the second blade, and a second blade. It is a control method of a water flow power generation device including a second pod provided with a second generator and a connecting portion connecting the first pod and the second pod. The region in which the first blade rotates when viewed from the direction in which the first rotation axis extends includes the first region in which the first blade overlaps the connecting portion, and the region in which the second blade rotates when viewed from the direction in which the second rotation shaft extends. Includes a second region where the second blade overlaps the connection. The control method of the water flow power generator is such that the timing at which the first blade passes through the first region and the timing at which the second blade passes through the second region are different from each other. A step for controlling the second rotation speed is provided.

In this water flow power generation device control method, the timing at which the first blade passes through the first region where the first blade overlaps the connecting portion and the timing at which the second blade passes through the second region where the second blade overlaps the connecting portion are set. The first rotation speed of the first blade and the second rotation speed of the second blade are controlled so as to be different from each other. Therefore, the possibility that the first blade and the second blade overlap the connecting portion at the same timing is reduced. As a result, the fluctuation range of the output power obtained by combining the first power generated based on the rotation of the first blade and the second power generated based on the rotation of the second blade is the first power and the second power, respectively. It is almost equal to the fluctuation range. As a result, it is possible to reduce the fluctuation range of the output power.

According to the present invention, it is possible to reduce the fluctuation range of the output power.

FIG. 1 is a diagram showing a schematic configuration of a power generation system including a control device according to an embodiment. FIG. 2 is a perspective view of a power generation device included in the power generation system shown in FIG. FIG. 3 is a system configuration diagram of the power generation system shown in FIG. FIG. 4 is a front view of the power generation device shown in FIG. FIG. 5A is a front view of the power generation device when one of the blades overlaps the connecting portion. FIG. 5B is a front view of the power generation device when the other blade overlaps the connecting portion. FIG. 6 is a flowchart showing an example of processing performed by the control device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

In the following description, the terms "upstream" or "downstream" are used with reference to the flow of water. The word "before" means the upstream side of the stream of water, and the word "after" means the downstream side of the stream of water. The terms "right" or "left" mean a direction perpendicular to and horizontal to the flow of water and are used with reference to the rear, or downstream view. The terms "upper" and "lower" are used with reference to the vertical line in a stable state of the power generation device 2 described later.

A power generation system including a control device according to an embodiment will be described with reference to FIGS. 1 to 4. FIG. 1 is a diagram showing a schematic configuration of a power generation system including a control device according to an embodiment. FIG. 2 is a perspective view of a power generation device included in the power generation system shown in FIG. FIG. 3 is a system configuration diagram of the power generation system shown in FIG. FIG. 4 is a front view of the power generation device shown in FIG.

The power generation system 1 (water flow power generation system) shown in FIG. 1 is a system that generates power using a sea current FW, which is a flow of water, and sends the output power Pout obtained by the power generation to, for example, an external power system. be. The power generation system 1 includes a power generation device 2 (water flow power generation device) installed in the sea and a ground device 21 (see FIG. 3) provided on the ground. The power generation device 2 and the ground device 21 are connected by cables 4a and 4b.

The power generation device 2 is an underwater floating power generation device installed in a state of being suspended in water such as the sea. The power generation device 2 is connected to the sinker 5 installed on the seabed B via a mooring line 3. The mooring line 3 may be connected to an anchor fixed to the seabed B instead of the sinker 5. The power generation device 2 receives the ocean current FW and generates the output power Pout.

The power generation device 2 sends the output power Pout to the ground device 21 via the cables 4a and 4b. One end of the cable 4a is connected to the power generation device 2. The other end of the cable 4a is connected to, for example, a repeater provided in the sinker 5. A cable 4b laid on the seabed B and extending to the ground device 21 is connected to the repeater of the sinker 5. The power generation system 1 sends the output power Pout generated by the power generation device 2 to the power system via the ground device 21.

As shown in FIG. 2, the power generation device 2 includes a pod 6A (first pod) and a pod 6B (second pod), a central pod 7, a connecting portion 8, and a turbine 9A and a turbine 9B. There is. The power generation device 2 is a twin-engine ocean current power generation device that generates electric power based on the rotation of the turbines 9A and 9B.

The pod 6A and the pod 6B are cylindrical containers having an internal space. The pods 6A and 6B are arranged apart from each other in the left-right direction. The pod 6A rotatably supports the turbine 9A and imparts proper buoyancy to the turbine 9A. The pod 6B rotatably supports the turbine 9B and imparts proper buoyancy to the turbine 9B. Pod 6A and Pod 6B have, for example, the same structure as each other.

The central pod 7 is a cylindrical container having an internal space. The central pod 7 is arranged between the pods 6A and 6B in the left-right direction, and is arranged above the pods 6A and 6B. The central pod 7 is provided with, for example, a tank for adjusting buoyancy, and the buoyancy applied to the power generation device 2 as a floating body is adjusted by pouring and draining seawater into the tank. The pods 6A, 6B, and the central pod 7 are arranged so that the central axes of the pods 6A, 6B, and the central pod 7 are substantially parallel to each other.

The connecting portion 8 is a structure that connects the pod 6A and the pod 6B. The connecting portion 8 includes a cross beam 8A and a cross beam 8B. The cross beam 8A is a plate-like structure extending between the pod 6A and the central pod 7. The cross beam 8A connects the pod 6A and the central pod 7. Specifically, one end of the cross beam 8A in the extending direction is connected to substantially the center of the pod 6A in the vertical direction, and the other end of the cross beam 8A is connected to the body of the central pod 7 facing the pod 6A. It is connected.

The cross beam 8B is a plate-like structure extending between the pod 6B and the central pod 7. The cross beam 8B connects the pod 6B and the central pod 7. Specifically, one end of the cross beam 8B in the extending direction is connected to substantially the center of the pod 6B in the vertical direction, and the other end of the cross beam 8B is connected to the body of the central pod 7 facing the pod 6B. It is connected. The pod 6A and the pod 6B are connected by a cross beam 8A and a cross beam 8B via a central pod 7.

Turbine 9A and turbine 9B convert the force received from the ocean current FW into mechanical rotational power. The turbine 9A is provided at the rear end of the pod 6A. The turbine 9A includes a hub 10A and a blade 11A (first blade) provided on the hub 10A. The blade 11A includes a blade 11a and a blade 11b. The hub 10A is connected to a rotating shaft 12A (see FIG. 3). By receiving the ocean current FW, the blade 11A rotates around the rotation shaft 12A (first rotation shaft) integrally with the hub 10A. The rotating shaft 12A is provided, for example, along the central axis of the pod 6A.

The turbine 9B is provided at the rear end of the pod 6B. The turbine 9B includes a hub 10B and a blade 11B (second blade) provided on the hub 10B. The blade 11B includes a blade 11c and a blade 11d. The hub 10B is connected to the rotating shaft 12B (see FIG. 3). By receiving the ocean current FW, the blade 11B is integrated with the hub 10B and rotates around the rotation shaft 12B (second rotation shaft). The rotating shaft 12B is provided, for example, along the central axis of the pod 6B. The rotary shaft 12A and the rotary shaft 12B are provided substantially parallel to each other.

As described above, in the power generation device 2, the blade 11A (turbine 9A) is arranged behind the pod 6A, and the blade 11B (turbine 9B) is arranged behind the pod 6B. That is, the downwind type turbine is adopted in the power generation device 2.

The pitches of the blades 11A and 11B are configured to be opposite to each other. Therefore, the blades 11A and 11B receive the ocean current FW and rotate in opposite directions to each other. Specifically, when viewed from the downstream (rear), the blade 11A rotates clockwise (rotation direction R1), and the blade 11B rotates counterclockwise (rotation direction R2).

As shown in FIG. 3, the power generation device 2 further includes a speed increaser 13A and a speed increaser 13B, a generator 15A (first generator), a generator 15B (second generator), and a power adjustment unit 16A. It also includes a power adjusting unit 16B, a control unit 17A and a control unit 17B, a rotation detection unit 18A and a rotation detection unit 18B, a flow velocity detection unit 19A and a flow velocity detection unit 19B, and a transformer 20.

The speed increaser 13A is a gear device to which the rotary shaft 12A and the rotary shaft 14A are connected. The speed increaser 13A is provided inside the pod 6A. The rotation of the rotating shaft 12A that rotates integrally with the blade 11A (turbine 9A) is transmitted to the speed increaser 13A. The speed increaser 13A rotates the rotary shaft 14A by increasing the rotation speed of the rotary shaft 12A. The rotation of the rotating shaft 14A is transmitted to the generator 15A.

The speed increaser 13B is a gear device to which the rotary shaft 12B and the rotary shaft 14B are connected. The speed increaser 13B is provided inside the pod 6B. The rotation of the rotating shaft 12B that rotates integrally with the blade 11B (turbine 9B) is transmitted to the speed increaser 13B. The speed increaser 13B rotates the rotary shaft 14B by increasing the rotation speed of the rotary shaft 12B. The rotation of the rotating shaft 14B is transmitted to the generator 15B. The speed increasing machines 13A and 13B increase the number of rotations of rotation by the blades 11A and 11B several tens of times, for example.

The generator 15A and the generator 15B convert kinetic energy due to rotation into electrical energy. The generator 15A is provided inside the pod 6A. The generator 15A includes, for example, a permanent magnet, and the permanent magnet rotates with the rotation of the rotating shaft 14A, so that the generator 15A generates electric power P1 (first electric power). In this way, the generator 15A generates the electric power P1 based on the rotation of the blade 11A. The generator 15A outputs the electric power P1 to the transformer 20 via the electric power adjusting unit 16A.

The generator 15B is provided inside the pod 6B. The generator 15B contains, for example, a permanent magnet, and the permanent magnet rotates with the rotation of the rotating shaft 14B, so that the generator 15B generates electric power P2 (second electric power). In this way, the generator 15B generates the electric power P2 based on the rotation of the blade 11B. The generator 15B outputs the electric power P2 to the transformer 20 via the electric power adjusting unit 16B.

The power adjusting unit 16A and the power adjusting unit 16B are PCS (Power Conditioning System) that adjust the frequency (phase), voltage value, and the like of the voltage in the electric power generated by the generator. The power adjusting unit 16A is provided inside the pod 6A and is communicably connected to the control unit 17A. The power adjusting unit 16B is provided inside the pod 6B, and is communicably connected to the control unit 17A via the control unit 17B. Each of the power adjusting unit 16A and the power adjusting unit 16B includes, for example, an inverter, an inverter control circuit for controlling the inverter, a converter, and a converter control circuit for controlling the converter. Each inverter control circuit and each converter control circuit are communicably connected to the control unit 17A. For example, the frequency and voltage value of the voltage in the power P1 are adjusted by electrically controlling the converter in the power adjusting unit 16A based on the command value regarding the frequency and the voltage value from the control unit 17A. Similarly, in the power adjusting unit 16B, the frequency and the voltage value of the voltage in the power P2 are adjusted by electrically controlling the converter.

Further, the electric power adjusting unit 16A and the electric power adjusting unit 16B adjust the rotation speed of the generator. For example, the rotation speed of the generator is adjusted by electrically controlling the inverter based on the command value regarding the rotation speed from the control unit 17A. The generator is in a regenerated state or a power running state due to the relationship between the turbine torque obtained from the ocean current FW and the electric torque generated by the generator. The rotation speed N1 (first rotation speed) of the blade 11A is adjusted by adjusting the rotation speed of the generator 15A by the power adjusting unit 16A. The rotation speed N2 (second rotation speed) of the blade 11B is adjusted by adjusting the rotation speed of the generator 15B by the power adjusting unit 16B.

The control unit 17A (control device) and the control unit 17B are computers that perform predetermined control. The control unit 17A is provided inside the pod 6A. The control unit 17B is provided inside the pod 6B. The control unit 17A and the control unit 17B are connected to each other so as to be communicable with each other. Each of the control unit 17A and the control unit 17B is composed of hardware such as a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory), and software such as a program stored in the ROM. It is a configured computer. In the present embodiment, in the power generation system 1, the control unit 17A controls the rotation of each of the blades 11A and 11B. In this case, the control unit 17B may be configured as a remote I / O (Input / Output) of the control unit 17A. The specific processing procedure performed by the control unit 17A will be described later.

The rotation detection unit 18A is a sensor that detects the rotation speed N1 and the rotation angle θ1. The rotation detection unit 18A is, for example, a resolver or a pulse encoder. The rotation detection unit 18A is provided on the rotation shaft 12A, for example, and detects the rotation speed N1 and the rotation angle θ1 based on the rotation of the rotation shaft 12A. As shown in FIG. 4, the rotation angle θ1 is the rotation angle of the blade 11A with reference to the position (reference position) of the blade 11A when overlapping with the cross beam 8A, and here is the rotation angle of the blade 11a. When the blade 11A (blade 11a) is located in the rotation direction R1 from the reference position of the blade 11A, the rotation angle θ1 has a positive value. The rotation angle θ2 of the blade 11b is 180 ° different from the rotation angle θ1 of the blade 11a. Each of the rotation angle θ1 and the rotation angle θ2 has a range of, for example, −180 ° to 180 °. The rotation detection unit 18A is communicably connected to the control unit 17A, and outputs the detected rotation speed N1 and rotation angle θ1 to the control unit 17A.

The rotation detection unit 18B is a sensor that detects the rotation speed N2 and the rotation angle θ3. The rotation detection unit 18B is, for example, a resolver or a pulse encoder. The rotation detection unit 18B is provided on the rotation shaft 12B, for example, and detects the rotation speed N2 and the rotation angle θ3 based on the rotation of the rotation shaft 12B. As shown in FIG. 4, the rotation angle θ3 is the rotation angle of the blade 11c with respect to the position (reference position) of the blade 11B when overlapping with the cross beam 8B. When the blade 11c is located in the rotation direction R2 from the reference position of the blade 11B, the rotation angle θ3 has a positive value. The rotation angle θ4 of the blade 11d is 180 ° different from the rotation angle θ3 of the blade 11c. Each of the rotation angle θ3 and the rotation angle θ4 has a range of, for example, −180 ° to 180 °. The rotation detection unit 18B is communicably connected to the control unit 17B, and outputs the detected rotation speed N2 and rotation angle θ3 to the control unit 17A via the control unit 17B.

The flow velocity detection unit 19A and the flow velocity detection unit 19B are sensors that detect the flow velocity of the ocean current FW received by the power generation device 2. The flow velocity detection unit 19A is provided, for example, at the lower end of the pod 6A. The flow velocity detection unit 19A is communicably connected to the control unit 17A, and outputs the detected flow velocity to the control unit 17A. The flow velocity detection unit 19B is provided, for example, at the lower end of the pod 6B. The flow velocity detection unit 19B is communicably connected to the control unit 17B, and outputs the detected flow velocity to the control unit 17A via the control unit 17B.

The transformer 20 boosts the voltage in the electric power P1 and the electric power P2, and generates the output electric power Pout by combining the electric power P1 and the electric power P2. The transformer 20 outputs the output power Pout to the outside of the power generation device 2. The output power Pout is sent to the ground device 21 via the cables 4a and 4b.

The ground device 21 has a transformer 22. The transformer 22 converts the output power Pout output from the power generation device 2 into a voltage value suitable for the external power system. The transformer 22 outputs the output power Pout having the converted voltage value to the external power system.

Since the downwind turbine is adopted in the power generation device 2, a region (flow velocity) in which the flow velocity of the ocean current FW is reduced by the cross beam 8A and the cross beam 8B is behind the connecting portion 8 (cross beam 8A and cross beam 8B). (Degraded area) occurs. Therefore, while each of the blades 11A and 11B passes through the flow velocity decreasing region, the force received by each of the blades 11A and 11B from the ocean current FW temporarily decreases. Since each of the blades 11A and 11B periodically passes through the flow velocity decreasing region, each of the electric power P1 and the electric power P2 fluctuates periodically.

In the initial state of the power generation device 2, the rotation of the blade 11A and the blade 11B is started from the initial positions of the blade 11A and the blade 11B in which the initial angle from the reference position of the blade 11A and the initial angle from the reference position of the blade 11B are different from each other. To. Alternatively, the rotation of the blade 11A and the blade 11B is started from the same position at the initial angle at different rotation speeds. That is, the rotation of the blade 11A and the blade 11B is started so that the timing at which the blade 11A passes through the cross beam 8A and the timing at which the blade 11B passes through the cross beam 8B are different from each other when the blade 11A and the blade 11B are rotating. To. Then, in the power generation device 2, the rotation speed N1 and the rotation speed N2 are adjusted so as to be equal to, for example, the command value from the control unit 17A. The command values of the rotation speed N1 and the rotation speed N2 are set to the same values so that the posture of the power generation device 2 is stable, and are changed according to the flow velocity. The power adjusting unit 16A adjusts the rotation of the blade 11A so that the blade 11A rotates at the command value of the rotation speed N1 based on the difference between the command value and the rotation speed of the blade 11A rotated by the force received from the ocean current FW, for example. do. The power adjusting unit 16B adjusts the rotation of the blade 11B so that the blade 11B rotates at the command value of the rotation speed N2 based on the difference between the command value and the rotation speed of the blade 11B rotated by the force received from the ocean current FW, for example. do.

At this time, the flow velocities of the ocean current FW received by each of the blades 11A and 11B are not always the same. Therefore, before the rotation speeds N1 and the rotation speeds N2 become equal to the command values, the rotation speeds of the blade 11A and the blade 11B due to the ocean current FW may be different from each other. As a result, in the process of adjusting the rotation speed N1 and the rotation speed N2 to the command values, the time interval ΔT between the timing when the blade 11A overlaps the cross beam 8A and the timing when the blade 11B overlaps the cross beam 8B changes from the initial state. In some cases. As a result, the time interval ΔT may be shortened. Therefore, in the power generation device 2, the rotations of the blades 11A and 11B are controlled so that the state in which the time interval ΔT is equal to or higher than a predetermined value is maintained.

Next, a method of controlling the rotation of the blades 11A and 11B performed by the control unit 17A will be described with reference to FIGS. 5 and 6. FIG. 5A is a front view of the power generation device when one of the blades overlaps the connecting portion. FIG. 5B is a front view of the power generation device when the other blade overlaps the connecting portion. FIG. 6 is a flowchart showing an example of processing performed by the control device. The control unit 17A stores a peripheral speed ratio table in which each value of the flow velocity and the rotation speeds of the blades 11A and 11B suitable for each flow velocity value are associated with each other. The threshold value δth is stored in advance in the control unit 17A. The threshold value δth is set to a value larger than the phase difference (for example, 0 °) at which the timing at which the blade 11A overlaps the cross beam 8A and the timing at which the blade 11B overlaps the cross beam 8B are the same.

5A and 5B show a front view of the power generation device 2 as viewed from the direction (rear) in which the rotary shaft 12A (rotary shaft 12B) extends. When viewed from the rear, the region DA in which the blade 11A rotates includes a region D1 (first region) where the blade 11A overlaps the cross beam 8A and a region D2 where the blade 11A does not overlap the cross beam 8A. When the blade 11A is located in the region D2, the blade 11A and the cross beam 8A are separated from each other by a predetermined distance along the rotation direction R1. The region DB in which the blade 11B rotates includes a region D3 (second region) in which the blade 11B overlaps the cross beam 8B and a region D4 in which the blade 11B does not overlap the cross beam 8B. When the blade 11B is located in the region D4, the blade 11B and the cross beam 8B are separated by a predetermined distance along the rotation direction.

The control unit 17A controls the rotation speed N1 and the rotation speed N2 so that the timing at which the blade 11A passes through the region D1 and the timing at which the blade 11B passes through the region D3 are different from each other. Specifically, as shown in FIG. 5A, the control unit 17A sets the rotation speed N1 and the rotation speed N2 so that the blade 11B is located in the region D4 at the timing when the blade 11A passes through the region D1. Control. Further, as shown in FIG. 5B, the control unit 17A controls the rotation speed N1 and the rotation speed N2 so that the blade 11A is located in the region D2 at the timing when the blade 11B passes through the region D3. ..

More specifically, as shown in FIG. 6, the control unit 17A first acquires the flow velocity (step S01). Specifically, the control unit 17A acquires the flow velocity detected by each of the flow velocity detection unit 19A and the flow velocity detection unit 19B.

Subsequently, the control unit 17A sets the rotation speed N1 and the rotation speed N2 to normal values which are the same values as each other according to the flow velocity acquired in step S01 (step S02). The normal value is the rotation speed suitable for the flow velocity, and the rotation speed suitable for the flow velocity can be obtained by referring to the peripheral speed ratio table. For example, the control unit 17A obtains the rotation speed suitable for the flow velocity output from the flow velocity detection unit 19A as a normal value by referring to the peripheral speed ratio table. Then, the control unit 17A transmits the acquired normal value as a command value to the power adjustment unit 16A and the power adjustment unit 16B. The power adjusting unit 16A adjusts the rotation of the blade 11A so that the rotation speed N1 becomes the command value (normal value), and the power adjusting unit 16B adjusts the rotation of the blade 11B so that the rotation speed N2 becomes the command value (normal value). Adjust the rotation of. As a result, the rotation speed N1 and the rotation speed N2 are set to the same value (normal value).

Subsequently, the control unit 17A acquires the rotation angle of the blade 11A and the rotation angle of the blade 11B (step S03). Specifically, the control unit 17A acquires the rotation angle θ1 detected by the rotation detection unit 18A, and acquires the rotation angle θ3 detected by the rotation detection unit 18B. Further, the control unit 17A acquires the rotation angle θ4 by adding 180 ° to the rotation angle θ3. When the added value obtained by adding 180 ° to the rotation angle θ3 exceeds 180 °, the control unit 17A further subtracts 360 ° from the added value to acquire the rotation angle θ4.

Subsequently, the control unit 17A calculates the phase difference δ (step S04). In step S04, for example, the control unit 17A calculates the difference Δθa (absolute value) between the rotation angle θ1 and the rotation angle θ3 and the difference Δθb (absolute value) between the rotation angle θ1 and the rotation angle θ4. Then, the control unit 17A compares the difference Δθa with the difference Δθb.

When the difference Δθa is smaller than the difference Δθb, the control unit 17A calculates the difference Δθa between the rotation angle θ1 (first rotation angle) and the rotation angle θ3 (second rotation angle) as the phase difference δ. At this time, the rotation angle θ3 is the rotation angle of the blade 11B from the reference position where the blade 11B overlaps the cross beam 8B. On the other hand, when the difference Δθa is equal to or greater than the difference Δθb, the control unit 17A calculates the difference Δθb between the rotation angle θ1 and the rotation angle θ4 (second rotation angle) as the phase difference δ. At this time, the rotation angle θ4 is the rotation angle of the blade 11B from the reference position where the blade 11B overlaps the cross beam 8B. As a result, the phase difference δ is calculated based on the combination of the blades 11c and 11d and the blade 11a, whichever has the smaller difference in rotation angle between them.

The control unit 17A may acquire the rotation angle θ2 (first rotation angle) by adding 180 ° to the rotation angle θ1. When the addition value obtained by adding 180 ° to the rotation angle θ1 exceeds 180 °, the control unit 17A may acquire the rotation angle θ2 by further subtracting 360 ° from the addition value. The control unit 17A may calculate the phase difference δ in the same manner as described above based on the difference between the rotation angle θ2 and the rotation angle θ3 and the difference between the rotation angle θ2 and the rotation angle θ4. Further, the control unit 17A may calculate the phase difference δ in the same manner as described above based on the difference between either one of the rotation angle θ3 and the rotation angle θ4 and each of the rotation angle θ1 and the rotation angle θ2. good.

Subsequently, the control unit 17A compares the phase difference δ and the threshold value δth (step S05). Specifically, the control unit 17A determines whether or not the phase difference δ calculated in step S04 is smaller than the predetermined threshold value δth.

When it is determined that the phase difference δ is smaller than the threshold value δth (step S05: YES), the control unit 17A changes at least one of the rotation speed N1 and the rotation speed N2 so that the phase difference δ is larger than the threshold value δth. do. Specifically, the control unit 17A sets the rotation speed N1 or the rotation speed N2 so that the rotation speed N1 and the rotation speed N2 are different from each other. For example, the control unit 17A sets the rotation speed N1 to a value different from the normal value, and maintains the rotation speed N2 to the normal value. When the phase (rotation angle) of the blade 11A is ahead of the phase (rotation angle) of the blade 11B, the control unit 17A sets the rotation speed N1 to a value larger than the normal value. On the other hand, when the phase of the blade 11A is behind the phase of the blade 11B, the control unit 17A sets the rotation speed N1 to a value smaller than the normal value. For example, when the phase difference δ is calculated by the rotation angle θ1 and the rotation angle θ3, when the blades 11A and 11B are rotating so that the blade 11a passes through the connecting portion 8 before the blade 11c. , The phase of the blade 11A is ahead of the phase of the blade 11B. For example, the control unit 17A sets at least one of the rotation speed N1 and the rotation speed N2 to a value different from the normal value within a range in which the posture of the power generation device 2 does not collapse.

The control unit 17A may set the rotation speed N2 to a value different from the normal value and maintain the rotation speed N1 to the normal value. The control unit 17A may set both the rotation speed N1 and the rotation speed N2 to values different from the normal values so that the rotation speed N1 and the rotation speed N2 are different from each other. As described above, when the phase difference δ becomes smaller than the threshold value δth, at least one of the rotation speed N1 and the rotation speed N2 is set to a value different from the normal value. For example, while the phase difference δ is smaller than the threshold value δth, the control unit 17A maintains the values of the rotation speed N1 and the rotation speed N2 changed to different values in step S06 for a predetermined time. The control unit 17A performs the process of step S01 again after the elapse of a predetermined time.

On the other hand, when it is determined in step S05 that the phase difference δ is equal to or greater than the threshold value δth (step S05: NO), the control unit 17A performs the process of step S01 again. As described above, when it is determined that the phase difference δ is equal to or greater than the threshold value δth, the rotation speeds N1 and N2 of the blades 11A and 11B are maintained at normal values. The control unit 17A repeats the processes from step S01 to step S05, for example, at predetermined intervals.

As described above, in the power generation system 1 including the control unit 17A, the rotation speed N1 and the rotation speed N2 are set so that the timing at which the blade 11A passes through the region D1 and the timing at which the blade 11B passes through the region D3 are different from each other. Be controlled. Therefore, the possibility that the blade 11A and the blade 11B overlap with the connecting portion 8 at the same timing is reduced. When the blade 11A and the blade 11B overlap the connecting portion 8 at the same timing, the fluctuation range of the output power Pout is the fluctuation of the power P1 and the power P2 caused by each of the blade 11A and the blade 11B passing through the connecting portion 8. It is almost equal to the sum of the widths. That is, the fluctuation range of the output power Pout becomes large. However, in the above configuration, the fluctuation range of the output power Pout is substantially equal to the fluctuation range of the power P1 and the power P2 caused by each of the blade 11A and the blade 11B passing through the connecting portion 8 independently. As a result, it is possible to reduce the fluctuation range of the output power Pout. That is, it is possible to reduce the influence (disturbance) on the external power system due to the fluctuation of the output power Pout.

The smaller the phase difference δ, the shorter the time interval ΔT between the timings at which the blades 11A and 11B each overlap the connecting portion 8. In the above-mentioned power generation system 1, the rotation speed N1 or the rotation speed N2 is set so that the phase difference δ becomes larger than the threshold value δth even if the phase difference δ becomes smaller than the threshold value δth. Specifically, the rotation speed N1 or the rotation speed N2 is set so that the rotation speed N1 and the rotation speed N2 have different values from each other. Therefore, as the phase difference δ gradually increases, the phase difference δ becomes larger than the threshold value δth. As a result, the timing at which the blade 11A overlaps the connecting portion 8 and the timing at which the blade 11B overlaps the connecting portion 8 are maintained in different states. As a result, it is possible to reduce the fluctuation range of the output power Pout.

The blade 11A and the blade 11B rotate in opposite directions. Therefore, the torques generated by the rotations of the blades 11A and 11B are opposite to each other, so that the posture of the power generation device 2 can be stabilized.

The rotation speed N1 and the rotation speed N2 at which high power generation efficiency can be obtained differ depending on the flow velocity. When the phase difference δ is equal to or greater than the threshold value δth, the rotation speed N1 and the rotation speed N2 are set to normal values which are the same values as each other according to the flow velocity. Therefore, by setting the normal value to a rotation speed at which high power generation efficiency can be obtained, the blade 11A and the blade 11B rotate at that rotation speed. As a result, it becomes possible to efficiently generate the electric power P1 and the electric power P2. Further, since the values of the respective torques generated by the rotation of the blades 11A and 11B are substantially the same as each other, the posture of the power generation device 2 can be further stabilized.

The power generation device 2 outputs the output power Pout, which is a combination of the power P1 and the power P2, to the ground device 21 via the cables 4a and 4b. Therefore, the number of cables for sending the electric power generated in the power generation device 2 from the power generation device 2 to the ground device 21 can be reduced as compared with the case where the electric power P1 and the electric power P2 are sent respectively. As a result, it becomes possible to simplify the installation work of the cables 4a and 4b in the sea.

Although one embodiment of the present invention has been described, the present invention is not limited to the above embodiment.

Although the central pod 7 is located above the pods 6A and 6B, the central pod 7 may be located at approximately the same height as the pods 6A and 6B. In this case, the cross beam 8A and the cross beam 8B may extend in substantially the same direction.

The connecting portion 8 may be a cross beam extending in one direction from the pod 6A to the pod 6B and directly connecting the pod 6A and the pod 6B without passing through the central pod 7. In this case, the central pod 7 may be provided above the cross beam. The power generation device 2 does not have to include the central pod 7. In this case, the transformer 20 may be provided inside either the pod 6A or the pod 6B.

The cross-sectional shape of the cross beams 8A and 8B in the direction intersecting the extending direction of the cross beams 8A and 8B does not have to be rectangular. The edge in the cross-sectional shape may be curved, for example, streamlined.

The shapes of the cross beams 8A and 8B seen from the rear (downstream) do not have to be rectangular. The edges of the cross beams 8A and 8B seen from the rear may be curved. The thickness (height) of the cross beams 8A and 8B may be larger than the maximum width along the rotation direction of the blades 11A and 11B, and may be equal to or less than the maximum width along the rotation direction.

The blade 11A may include three or more blades, and the blade 11B may include three or more blades. When the blade 11A (blade 11B) is composed of three blades, the control unit 17A determines the rotation angle of one of the three blades in the blade 11A and the rotation angle of the three blades in the blade 11B. The phase difference δ may be calculated based on the difference from each rotation angle. Even when the blade 11A (blade 11B) is composed of four or more blades, the control unit 17A may calculate the phase difference δ in the same manner.

The rotation speed N1 and the rotation speed N2 may be controlled by the control unit 17B (control device). In this case, the control unit 17A may be configured as a remote I / O of the control unit 17B. The power generation device 2 may include another control unit in the central pod 7. In this case, the rotation speed N1 and the rotation speed N2 may be controlled by the control unit (control device) provided in the central pod 7. The power generation system 1 is provided on the ground and is provided along the cables 4a and 4b with another control unit for managing the power generation device 2, and is a communication that connects the power generation device 2 and the other control units in a communicable manner. It may be equipped with a cable. In this case, the rotation speed N1 and the rotation speed N2 may be controlled by a control unit (control device) provided on the ground.

After the rotation speed N1 and the rotation speed N2 are set to different values in step S06, the processing performed by the control unit 17A after the lapse of a predetermined time returns to the processing of step S01, but the condition for returning to the processing of step S01 is , Not limited to this. The control unit 17A may perform the process of step S01 again by setting the rotation speed N1 and the rotation speed N2 to different values and then determining that the phase difference δ is equal to or more than the threshold value δth. That is, the control unit 17A may repeat the processes of steps S03 to S05 until the phase difference δ becomes the threshold value δht or more after the process of step S06. Alternatively, the control unit 17A may use another threshold value having a value larger than the threshold value δth in order to determine whether or not to return to the process of step S01. In this case, it is possible to reduce the possibility that the phase difference δ falls below the threshold value δth immediately after the rotation speed N1 and the rotation speed N2 return to the normal values.

The rotation detection unit 18A may be provided on the rotation shaft 14A. In this case, the control unit 17A may acquire the rotation speed N1 and the rotation angles θ1 and θ2 based on the rotation of the rotation shaft 14A. The rotation detection unit 18B may be provided on the rotation shaft 14B. In this case, the control unit 17A may acquire the rotation speed N2 and the rotation angles θ3 and θ4 based on the rotation of the rotation shaft 14B. The control unit 17A may acquire the rotation speed N1 and the rotation angles θ1 and θ2 by calculating the rotation position (pole position) of the permanent magnet from the voltage value that changes periodically in the electric power P1. The control unit 17A may detect the rotation speed N2 and the rotation angles θ3 and θ4 by calculating the rotation position (pole position) of the permanent magnet from the voltage value that changes periodically in the electric power P2.

The rotation speed N1 and the rotation speed N2 are adjusted by the power adjustment unit 16A and the power adjustment unit 16B, respectively, but the adjustment means for the rotation speeds N1 and N2 are not limited to this. The power generation device 2 may include a device for adjusting the rotation speed N1 and the rotation speed N2 by a mechanical mechanism. For example, the power generation device 2 is connected to the rotation shaft 14A (rotational shaft 14B), and is a brake device that adjusts the rotation speed N1 (rotational speed N2) by reducing the rotation speed N1 (rotational speed N2) by using frictional force. You may prepare.

The power generation device 2 may send the electric power P1 and the electric power P2 to the ground device 21 by different cables. In this case, the ground device 21 may output the output power Pout obtained by synthesizing the power P1 and the power P2 in the ground device 21 to an external power system.

The power generation system 1 may include a power storage device for smoothing the output power Pout. This power storage device is, for example, a secondary battery or a capacitor, and switches between charging and discharging according to fluctuations in the output power Pout. This smoothes the power output to the external power system. In the power generation system 1, since the fluctuation range of the output power Pout is reduced, the capacity of the power storage device can be reduced.

1 Power generation system 2 Power generation device 6A Pod 6B Pod 8 Connection part 8A Cross beam 8B Cross beam 11A Blade 11B Blade 12A Rotation shaft 12B Rotation shaft 15A Generator 15B Generator 17A Control unit 18A Rotation detection unit 18B Rotation detection unit 19A Flow detection unit 19B Flow rate detector N1 Rotation number N2 Rotation number θ1 Rotation angle θ2 Rotation angle θ3 Rotation angle θ4 Rotation angle δ Phase difference δth Threshold

Claims (7)

A first blade that rotates around a first rotation axis, a first generator that generates a first electric power based on the rotation of the first blade, and a first pod provided with the first blade and the first generator. , A second blade that rotates around the second rotation axis, a second generator that generates a second electric power based on the rotation of the second blade, and a second pod provided with the second blade and the second generator. A control device for controlling a water current power generation device including a connecting portion for connecting the first pod and the second pod.
The water flow power generation device is installed so that the end portion of the first pod provided with the first blade and the end portion of the second pod provided with the second blade are located downstream of the connecting portion. Ori,
The region in which the first blade rotates when viewed from the direction in which the first rotation axis extends includes the first region in which the first blade overlaps the connecting portion.
The region in which the second blade rotates when viewed from the direction in which the second rotation axis extends includes a second region in which the second blade overlaps the connecting portion.
The first rotation speed of the first blade and the second of the second blade so that the timing at which the first blade passes through the first region and the timing at which the second blade passes through the second region are different from each other. Control the number of revolutions,
Control device. The first rotation angle of the first blade with respect to the first blade when it is located in the first region is acquired, and the first rotation angle is acquired.
The second rotation angle of the second blade with respect to the second blade when it is located in the second region is acquired, and the second rotation angle is acquired.
When the phase difference, which is the difference between the first rotation angle and the second rotation angle, becomes smaller than a predetermined threshold value, the first rotation speed or the phase difference becomes larger than the threshold value. Set the second rotation speed,
The control device according to claim 1. When the phase difference is larger than the threshold value, the first rotation speed and the second rotation speed are the same values as each other according to the flow velocity detected by the flow velocity detection unit provided in the water flow power generation device. Set to
When the phase difference becomes smaller than the threshold value, the first rotation speed or the second rotation speed is set so that the first rotation speed and the second rotation speed are different from each other.
The control device according to claim 2. A water flow power generation device and a control device for controlling the water flow power generation device are provided.
The water flow power generator includes a first blade that rotates around a first rotation axis, a first generator that generates first electric power based on the rotation of the first blade, and the first blade and the first generator. A first pod provided, a second blade rotating around a second rotation axis, a second generator that generates a second electric power based on the rotation of the second blade, the second blade, and the second generator. Has a second pod provided with a pod, and a connecting portion for connecting the first pod and the second pod.
The water flow power generation device is installed so that the end portion of the first pod provided with the first blade and the end portion of the second pod provided with the second blade are located downstream of the connecting portion. Ori,
The region in which the first blade rotates when viewed from the direction in which the first rotation axis extends includes the first region in which the first blade overlaps the connecting portion.
The region in which the second blade rotates when viewed from the direction in which the second rotation axis extends includes a second region in which the second blade overlaps the connecting portion.
In the control device, the first rotation speed of the first blade and the first rotation so that the timing at which the first blade passes through the first region and the timing at which the second blade passes through the second region are different from each other. Controls the second rotation speed of 2 blades,
Water flow power generation system. The first blade and the second blade rotate in opposite directions.
The water flow power generation system according to claim 4. The water flow power generation device outputs the output power obtained by synthesizing the first power and the second power to the outside.
The water flow power generation system according to claim 4 or 5. A first blade that rotates around a first rotation axis, a first generator that generates a first electric power based on the rotation of the first blade, and a first pod provided with the first blade and the first generator. , A second blade that rotates around the second rotation axis, a second generator that generates a second electric power based on the rotation of the second blade, and a second pod provided with the second blade and the second generator. A method for controlling a water flow power generator, comprising a connecting portion for connecting the first pod and the second pod.
The water flow power generation device is installed so that the end portion of the first pod provided with the first blade and the end portion of the second pod provided with the second blade are located downstream of the connecting portion. Ori,
The region in which the first blade rotates when viewed from the direction in which the first rotation axis extends includes the first region in which the first blade overlaps the connecting portion.
The region in which the second blade rotates when viewed from the direction in which the second rotation axis extends includes a second region in which the second blade overlaps the connecting portion.
The first rotation speed of the first blade and the second of the second blade so that the timing at which the first blade passes through the first region and the timing at which the second blade passes through the second region are different from each other. With a step to control the number of revolutions,
How to control a water current generator.

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