Tidal current power generation device and control method thereof

Abstract

The application discloses a tidal current energy power generation device and a control method thereof. The device comprises a main frame, a water turbine, a suspension system and an anchoring system. The suspension system comprises a main float body arranged on the upper part of the main frame and used for providing main buoyancy for the device, and an adjustable float body arranged on the lower part of the main frame and used for adjusting the overall buoyancy of the device. The adjustable float body is provided with a chamber for containing ballast water and a water inlet and outlet mechanism communicated with the chamber. Through the arrangement of the main float body and the adjustable float body of the suspension system and the structural design of the chamber and the water inlet and outlet mechanism in the adjustable float body, a tidal current energy power generation device configuration with adjustable buoyancy is formed, the active adjustment function of the working water depth of the device changing with the flow velocity is realized, the power generation efficiency of the water turbine in the low flow velocity area is improved, the safety problem of the prior art caused by the fixed working water depth under the extreme sea conditions is solved, and the energy capturing capacity and the environmental adaptability of the device in the whole life cycle are significantly improved.

Description

Technical Field

[0001] This invention relates to tidal energy generation equipment, and more particularly to a tidal energy generation device and its control method. Background Technology

[0002] Tidal energy, as a marine renewable energy source with advantages such as high predictability, high energy density, and relatively low environmental impact, has received widespread attention globally in recent years. With the increasing depletion of fossil fuels and growing environmental pressures, research and application of tidal power generation technology have deepened, gradually expanding from nearshore high-velocity areas to the deep sea. Existing tidal power generation devices mainly include horizontal-axis turbines and vertical-axis turbines, typically fixed to the seabed by a base or suspended in the water by a floating body. In floating tidal energy devices, a floating body is usually used to provide buoyancy, suspending the device at a set water depth, and it is moored to the seabed by an anchoring system to ensure stable operation under tidal currents. However, the tidal current velocity in deep-sea areas exhibits significant spatial distribution characteristics, with large differences in velocity at different water depths and periodic variations over time. Existing floating tidal energy devices mostly use fixed buoyancy structures, making it difficult to adjust their operating depth once set, and unable to actively change their vertical position in the water according to changes in current velocity. When the water flow velocity is low in the area where the device is located, the power generation efficiency of the turbine will decrease significantly, making it difficult to achieve the expected total annual power generation. Conversely, when encountering extreme sea conditions and excessively high flow velocities, the device faces excessive hydrodynamic impact loads, posing a risk of structural damage. These issues limit the power generation efficiency and operational safety of floating tidal energy devices in complex marine environments, making it difficult to achieve economical and effective development and utilization in deep-sea low-flow areas. Summary of the Invention

[0003] Purpose of the invention: The purpose of this invention is to provide a tidal current power generation device that can actively adapt to changes in flow velocity, is efficient and safe and reliable. Another purpose of this invention is to provide a control method for such a device.

[0004] Technical solution: The tidal power generation device of the present invention includes a main frame, a turbine installed on the main frame, a suspension system that provides buoyancy to the device, and an anchoring system for mooring the device to the seabed; the suspension system includes a main float located on the upper part of the main frame and used to provide the main buoyancy to the device, and an adjustable float located on the lower part of the main frame and used to adjust the overall buoyancy of the device; the adjustable float is provided with a chamber for accommodating ballast water and an inlet and outlet mechanism communicating with the chamber.

[0005] Preferably, the main frame includes a flow guide, and the turbine is rotatably mounted inside the flow guide. The flow guide is a pipe structure comprising a converging section and a diffuser section along the flow direction. The converging section of the flow guide accelerates the incoming flow, enabling low-velocity water to reach the turbine's rated operating velocity, while the diffuser guides the water to flow out smoothly, reducing wake loss and thus improving the turbine's energy capture efficiency.

[0006] Preferably, the main float comprises at least two buoyancy units and an airfoil float structure connecting the buoyancy units; the cross-section of the airfoil float structure is airfoil-shaped. Under the action of water flow, the airfoil float structure can generate additional lift, providing more stable buoyancy support to the main float on one hand, and improving the flow field distribution around the device on the other, reducing the hydrodynamic impact on the entire device.

[0007] Preferably, the buoyancy unit includes airbags symmetrically arranged on both sides of the upper part of the main frame; the airfoil-shaped floating structure is connected between the airbags, and its middle part is fixedly connected to the center of the upper part of the main frame. The symmetrical arrangement of the airbags ensures that the main float is subjected to uniform force, ensuring that the device maintains a good balance in the water; the fixed connection between the airfoil-shaped floating structure and the center of the main frame forms a stable triangular support structure, enhancing the connection rigidity between the main float and the main frame.

[0008] Preferably, the adjustable float is a multi-watertight compartment airbag, which is symmetrically arranged along the lower part of the main frame and has a partition inside, which divides the chamber into multiple independent watertight compartments.

[0009] Preferably, the partition includes vertical partitions and horizontal partitions; each watertight compartment is connected to an inlet / outlet mechanism, which includes an inlet / outlet valve and a water pump. The ballast water volume of different compartments can be adjusted as needed to achieve precise adjustment of the device's buoyancy and attitude.

[0010] Preferably, the anchoring system includes an anchor, a main mooring chain connecting the anchor to the top of the main frame, and secondary mooring chains connecting the anchor to the side of the main frame. The secondary mooring chains are symmetrically arranged along the side of the main frame to limit the lateral sway of the device, and there are two or more of them. The main mooring chain is larger than the secondary mooring chains. The anchor includes a main body and an outer wing located on the outside of the main body. The upper part of the outer wing is gentle, and the lower part is steep. The design of the outer wing, with its gentle upper part and steep lower part, makes the anchor sink more easily when it enters the soil due to less resistance, while the steep lower part generates greater soil resistance when subjected to upward pulling force, providing a stronger anchoring force.

[0011] Preferably, the system further includes a sensing and control system, which comprises a central control unit and a flow rate sensor; the central control unit is electrically connected to both the flow rate sensor and the inlet / outlet drainage mechanism. The sensing and control system automatically adjusts its operating status based on real-time flow rate information.

[0012] A method for controlling the operating water depth of the above-mentioned device includes the following steps:

[0013] The flow velocity information of the water body where the device is located is obtained through a flow velocity sensor;

[0014] The central control unit determines whether the flow rate information deviates from the preset target flow rate range;

[0015] When the flow velocity is lower than the target flow velocity range, the central control unit controls the inlet and outlet mechanism to discharge ballast water from the chamber of the adjustable float, reducing the total weight of the device and causing the device to float.

[0016] When the flow velocity exceeds the target flow velocity range, the central control unit controls the inlet and outlet mechanism to inject ballast water into the chamber of the adjustable float, increasing the total weight of the device and causing it to submerge.

[0017] Preferably, it also includes an extreme flow velocity protection step: when the flow velocity exceeds the preset limit value, the central control unit controls the turbine blades to rotate to a feathering state and stops generating electricity, while injecting ballast water into the adjustable float to submerge the device.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: By setting the suspension system to include a main float that provides the main buoyancy and an adjustable float located at the bottom for adjusting the overall buoyancy, and combining the structural design of the adjustable float with a cavity and water inlet and outlet mechanism, a tidal energy power generation device configuration with adjustable buoyancy is formed. This realizes the active adjustment function of the device's working water depth with the change of flow velocity, which not only improves the power generation efficiency of the turbine in the low flow velocity region, but also solves the problem of insufficient safety in extreme sea conditions caused by the fixed working water depth in the prior art, and significantly improves the energy capture capability and environmental adaptability of the device throughout its entire life cycle. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention;

[0020] Figure 2 This is a schematic diagram of the control method logic of the present invention;

[0021] Figure 3 This is a schematic diagram of the flow guide structure of the present invention;

[0022] Figure 4 This is a schematic diagram of the transverse connecting rod structure in an embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram of the buoyancy unit and airfoil floating body structure of the present invention;

[0024] Figure 6 This is a schematic diagram of the adjustable buoy structure of the present invention;

[0025] Figure 7 This is a schematic diagram of the anchor structure of the present invention;

[0026] Figure 8 This is a schematic diagram of the extreme flow rate protection steps of the present invention. Detailed Implementation

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0028] like Figures 1 to 8 As shown in the figure, this embodiment provides a tidal energy power generation device and its control method. The device as a whole includes a main frame 1, a turbine 2 mounted on the main frame 1, a suspension system 3 that provides buoyancy to the device, and an anchoring system 4 that moors the device to the seabed. The main frame 1 serves as the load-bearing structure of the entire device, supporting components such as the turbine 2 and the suspension system 3, and is fixed to a predetermined position in the sea area by the anchoring system 4. The suspension system 3 provides buoyancy to the device, enabling it to remain suspended in the water; the anchoring system 4 moors the device to the seabed, ensuring stable operation under tidal currents. When the tidal current passes through the device, the water flows into the turbine 2 and drives it to rotate, thereby converting tidal energy into mechanical energy, which is further converted into electrical energy output through the power generation device. The electrical energy generated by the turbine 2 can be connected to an external power transmission cable through a cable interface set on the main frame 1 and transmitted to an offshore or onshore power system.

[0029] The hub 143 of the turbine 2 is connected to the generator via the main shaft. The generator is mounted on the rear side of the guide fairing 11 and fixed to the transverse connecting rod 14 or the main frame 1. When the turbine 2 rotates under the action of the tidal current, it directly drives the generator rotor to rotate via the main shaft, thereby converting the mechanical energy of the water flow into electrical energy output. The generator output is connected to an external power transmission cable via a cable interface, realizing the transmission of electrical energy to the offshore or onshore power system.

[0030] like Figure 3 As shown, the main frame 1 includes a flow guide shroud 11, and the turbine 2 is rotatably mounted inside the flow guide shroud 11. Inside the flow guide shroud 11 is a cross-shaped support structure 12 for supporting the turbine 2. The support structure 12 connects the inner wall of the flow guide shroud 11 to a transverse connecting rod 14, which is located at the center of the flow guide shroud 11 and is substantially coaxial with the axis of the flow guide shroud 11. The turbine 2 is connected to the main frame 1 via a hub 143 mounted on the transverse connecting rod 14, thereby enabling the turbine 2 to be stably mounted inside the flow guide shroud 11 and rotated by the water flow.

[0031] like Figure 1 , Figure 5 , Figure 6 As shown, the suspension system 3 includes a main float located on the upper part of the main frame 1 to provide the main buoyancy for the device, and an adjustable float located on the lower part of the main frame 1 to adjust the overall buoyancy of the device. The main float provides the main buoyancy for the tidal power generation device, enabling the device to remain suspended in the water. The adjustable float adjusts the overall buoyancy of the device by changing the amount of ballast water inside it, allowing the device to operate stably at different water depths. The adjustable float has a chamber for containing ballast water and an inlet / outlet mechanism connected to the chamber. By controlling the inlet / outlet mechanism to inject or discharge ballast water into the chamber, the weight of the adjustable float can be changed, thereby changing the overall floating / sinking state of the device and adjusting the operating water depth of the device.

[0032] like Figure 3 As shown, multiple connecting components for connecting the suspension system 3 and the anchoring system 4 are also provided on the outer wall of the main frame 1. These connecting components can be ear plates, connecting seats, or hinged supports, and are fixedly connected to the main float and adjustable float by bolts, pins, or welding, allowing each structure to be stably installed around the main frame 1. The flow guide shroud 11 is a pipe structure that includes a contraction section and a diffusion section along the flow direction. The flow guide shroud 11 forms a relatively small inlet opening in the incoming flow direction and a larger outlet opening in the opposite direction of the incoming flow, forming a relatively narrow annular flow channel. This causes the water flow to converge and accelerate when entering the flow guide shroud 11, thereby increasing the flow velocity through the turbine 2 area. When the water flows through the flow guide shroud 11, it first enters the contraction section, where the flow velocity gradually increases. It then enters the diffusion section, where the fluid gradually diffuses, thus creating relatively stable and concentrated flow conditions at the turbine 2, improving the flow collection efficiency of the turbine 2. By setting up the above-mentioned flow guiding structure, the water flow can be guided and accelerated when the tidal current passes through, so that the water flow acts more concentratedly on the turbine blades 2, thereby improving the energy utilization efficiency of turbine 2 and reducing the impact of turbulence on the stable operation of the turbine.

[0033] like Figure 5As shown, the main float includes at least two buoyancy units 32 and an airfoil-shaped float structure 33 connecting the buoyancy units 32. The buoyancy units 32 provide the main buoyancy, and the airfoil-shaped float structure 33 connects the buoyancy units 32 to form an overall buoyancy structure. Simultaneously, the airfoil structure reduces water flow resistance and improves the overall stability of the device under the influence of water flow. The airfoil-shaped float structure 33 has an airfoil-like cross-section, giving it good hydrodynamic performance under the influence of water flow. Under the influence of water flow, the airfoil-shaped float structure 33 can create a hydrofoil-like fluid effect, thereby improving the flow field distribution around the device to a certain extent, reducing the hydrodynamic impact on the device, and improving the operational stability of the device in tidal environments. The buoyancy unit 32 includes airbags symmetrically arranged on both sides of the upper part of the main frame 1. The airfoil-shaped float structure 33 connects between the two airbags, and its central part is fixedly connected to the center of the upper part of the main frame 1, allowing the main float to be stably installed on the upper part of the main frame 1 and forming an overall buoyancy structure, thus ensuring the stable suspension of the device in the water.

[0034] like Figure 6 As shown, the adjustable buoy is a multi-watertight compartment airbag 31, which is symmetrically arranged along the lower part of the main frame 1 to ensure that the device can maintain a good balance during buoyancy adjustment. The multi-watertight compartment airbag 31 has internal baffles that divide the chamber into multiple independent watertight compartments, each independent of the others, thus improving the safety and reliability of the structure. Through the multi-watertight compartment structure, when one watertight compartment is damaged or leaks, the remaining compartments can remain sealed and continue to provide buoyancy, thus preventing the entire device from losing buoyancy and sinking, improving the operational safety of the device in the marine environment. The multi-watertight compartment airbag 31 can be made of high-strength flexible composite material, with the internal baffles fixedly connected to the airbag wall by sealing welding or bonding, forming multiple independent and sealed watertight compartment structures to ensure good sealing and structural stability under ballast water.

[0035] The bulkhead includes vertical bulkheads 311 and horizontal bulkheads 312. The combination of vertical bulkheads 311 and horizontal bulkheads 312 creates multiple independent watertight compartment structures within the multi-watertight compartment airbag 31. Each watertight compartment is connected to an inlet / outlet mechanism, which includes an inlet / outlet valve 313 and a water pump. By controlling the operation of the inlet / outlet valve 313 and the water pump, ballast water can be injected into or discharged from each watertight compartment, thereby adjusting the overall buoyancy of the adjustable float. When maintenance or repair is required, the ballast water in the adjustable float can be discharged to allow the entire device to float to near the water surface, facilitating maintenance and repair of the turbine 2 and related equipment.

[0036] The intake and drainage mechanisms are located within each watertight compartment and connected to the outside via openable and closable through-holes. The pumps within these mechanisms pump external seawater into the watertight compartments or discharge ballast water from the compartments to the external seawater environment. Intake and drainage valves 313 control the connection or closure of the openable and closable through-holes between each watertight compartment and the external seawater. Each watertight compartment can have its own independent piping or be connected to the same pump via distribution piping, thereby enabling the adjustment of ballast water levels in different compartments.

[0037] like Figure 7 As shown, the anchoring system 4 is used to fix the tidal power generation device to the seabed. It includes an anchor 41, a main mooring chain 42 connecting the anchor 41 to the top of the main frame 1, and secondary mooring chains 43 connecting the anchor 41 to the side of the main frame 1. The main mooring chain 42 primarily bears the overall mooring load of the device, enabling it to be stably moored to the seabed. The secondary mooring chains 43 are symmetrically arranged along the side of the main frame 1 to limit the lateral sway of the device under tidal currents, thereby improving the device's stability in the current. The combination of the main mooring chain 42 and the secondary mooring chains 43 ensures stable mooring of the device in the vertical direction and restricts its attitude when the tidal direction changes, allowing the tidal power generation device to maintain a relatively stable attitude in complex ocean current environments. Two or more secondary mooring chains 43 are used to further enhance the device's stable mooring capability. The main mooring chain 42 is larger than the secondary mooring chain 43, enabling the main mooring chain 42 to bear the main load, while the secondary mooring chain 43 is mainly used to stabilize the attitude of the device. The anchor 41 includes a cylindrical body 411 and outer flanges 412 disposed around the periphery of the body 411. The upper part of the outer flanges 412 is gentle, while the lower part is steep, providing a good gripping effect in the seabed soil, thereby improving the stability of the anchoring system 4. To reduce the hydrodynamic resistance experienced by the device under tidal currents, the structural parts in direct contact with the water flow can adopt rounded corner transition structures, thereby reducing the impact of the water flow and improving the operational stability of the device.

[0038] The tidal power generation device also includes a sensing and control system. This system includes a central control unit 51 and a flow velocity sensor 52. The flow velocity sensor 52 acquires the flow velocity information of the water body where the device is located. The central control unit 51 is electrically connected to both the flow velocity sensor 52 and the inlet / outlet mechanism. The sensing and control system 51 also includes a power supply unit, which can be a battery pack or energy storage power source, installed inside the main frame 1. This unit provides power to the central control unit 51, the flow velocity sensor 52, the inlet / outlet mechanism, and the blade adjustment drive mechanism. When the device has not yet started generating electricity or the power generation is insufficient, the power supply unit provides initial power to the system. After the device enters a stable power generation state, some of the power generated by the generator can be used to supplement the power supply unit, thereby ensuring the continuous and stable operation of the device's control system. The central control unit 51 can control the inlet / outlet mechanism based on the flow velocity information collected by the flow velocity sensor 52, thereby achieving automatic adjustment of the ballast water inside the adjustable float. The central control unit 51 is also electrically connected to the blade adjustment drive mechanism of the turbine 2 (not shown in the figure) to control the rotation angle of the turbine 2 blades. The blades of the turbine 2 are rotatably mounted on the hub 143. Each blade has a pitch shaft at its root. An electric pitch drive mechanism is located inside the hub 143. This electric pitch drive mechanism is connected to each pitch shaft via a gear transmission structure, enabling it to drive the blades to rotate around the pitch shafts under the control of the central control unit 51, thereby changing the blade angle of attack. When the central control unit 51 issues a protection command, the drive mechanism rotates the blades to a feathering position to reduce the driving force exerted by the water flow on the blades.

[0039] like Figure 2 and Figure 8As shown, during the operation of the device, the flow velocity sensor 52 continuously acquires the flow velocity information of the water body where the device is located and transmits it to the central control unit 51. When the central control unit 51 determines that the flow velocity is lower than the preset target flow velocity range, the central control unit 51 controls the inlet and outlet mechanism to operate, and discharges the ballast water in the adjustable float chamber through the water pump and inlet and outlet valve 313, reducing the overall weight of the adjustable float, thereby causing the tidal power generation device to float as a whole, allowing the turbine 2 to enter the water layer area with a higher flow velocity to operate. When the central control unit 51 determines that the flow velocity is higher than the target flow velocity range, the central control unit 51 controls the inlet and outlet mechanism to inject ballast water into the chamber of the adjustable float, increasing the overall weight of the adjustable float, thereby causing the tidal power generation device to submerge as a whole, allowing the turbine 2 to enter the water layer area with a more suitable flow velocity. When the flow velocity further increases and exceeds the preset limit flow velocity threshold, the central control unit 51 can also control the turbine 2 to enter the protection state. Under the limit flow velocity condition, the central control unit 51 prioritizes controlling the turbine 2 blades to enter the feathering state to reduce the hydrodynamic load. After entering the protection state, the central control unit 51 can also control the inlet and outlet mechanisms to inject ballast water into the chamber of the adjustable float, causing the entire device to submerge further to a water layer with a lower flow velocity. Simultaneously, it disconnects the generator from the external power grid, stopping the turbine's power generation operation and further reducing the stress on the device. When the flow velocity returns to the target range, the central control unit 51 can control the drive mechanism to restore the turbine 2's blades to the normal power generation angle and control the inlet and outlet mechanisms to stop injecting or draining water, restoring the device to a suitable operating water depth for power generation and thus re-entering normal power generation mode. Through this method, the tidal power generation device can automatically adjust its operating water depth according to changes in water flow velocity, thereby maintaining the turbine 2 in a suitable flow velocity environment, improving tidal power generation efficiency, and ensuring the stability of the device's operation.

Claims

1. A tidal current power generation device, comprising a main frame (1), a turbine (2) mounted on the main frame (1), a suspension system (3) providing buoyancy to the device, and an anchoring system (4) for mooring the device to the seabed; characterized in that, The suspension system (3) includes a main float located on the upper part of the main frame (1) and used to provide the main buoyancy of the device, and an adjustable float located on the lower part of the main frame (1) and used to adjust the overall buoyancy of the device; the adjustable float is provided with a chamber for accommodating ballast water and an inlet and outlet mechanism communicating with the chamber.

2. The tidal power generation device according to claim 1, characterized in that, The main frame (1) includes a flow guide (11), and the water turbine (2) is rotatably installed inside the flow guide (11); the flow guide (11) is a pipe structure that includes a contraction section and a diffusion section in sequence along the flow direction.

3. The tidal power generation device according to claim 1, characterized in that, The main float includes at least two buoyancy units (32) and an airfoil float structure (33) connected between the buoyancy units (32); the cross-section of the airfoil float structure (33) is an airfoil.

4. The tidal power generation device according to claim 3, characterized in that, The buoyancy unit (32) includes airbags symmetrically arranged on both sides of the upper part of the main frame (1); the airfoil floating structure (33) is connected between the airbags, and its middle part is fixedly connected to the upper center of the main frame (1).

5. The tidal power generation device according to claim 1, characterized in that, The adjustable float is a multi-watertight compartment airbag (31), which is symmetrically arranged along the lower part of the main frame (1). It has a partition inside, which divides the chamber into multiple independent watertight compartments.

6. The tidal power generation device according to claim 5, characterized in that, The partition includes a vertical partition (311) and a horizontal partition (312); each of the watertight compartments is connected to an inlet / outlet mechanism, which includes an inlet / outlet valve (313) and a water pump.

7. The tidal power generation device according to claim 1, characterized in that, The anchoring system (4) includes an anchor (41), a main mooring chain (42) connecting the anchor (41) and the top of the main frame (1), and a secondary mooring chain (43) connecting the anchor (41) and the side of the main frame (1). The secondary mooring chains (43) are symmetrically arranged along the side of the main frame (1) to limit the lateral swing of the device, and there are two or more of them. The main mooring chain (42) is larger than the secondary mooring chain (43). The anchor (41) includes a main body (411) and an outer wing (412) located on the outside of the main body (411). The upper part of the outer wing (412) is gentle and the lower part is steep.

8. The tidal power generation device according to claim 1, characterized in that, It also includes a perception control system, which includes a central control unit (51) and a flow rate sensor (52); the central control unit (51) is electrically connected to the flow rate sensor (52) and the inlet and outlet drainage mechanism respectively.

9. A method for controlling the operating water depth of the device according to any one of claims 1-8, characterized in that, Includes the following steps: The flow velocity information of the water body where the device is located is obtained by the flow velocity sensor (52); The central control unit (51) determines whether the flow velocity information deviates from the preset target flow velocity range; When the flow velocity is lower than the target flow velocity range, the central control unit (51) controls the inlet and outlet mechanism to discharge ballast water from the chamber of the adjustable float, reducing the total weight of the device and causing the device to float. When the flow rate is higher than the target flow rate range, the central control unit (51) controls the inlet and outlet mechanism to inject ballast water into the chamber of the adjustable float, increasing the total weight of the device and causing the device to submerge.

10. The method according to claim 9, characterized in that, It also includes an extreme flow velocity protection step: when the flow velocity exceeds the preset limit value, the central control unit (51) controls the turbine (2) blades to rotate to the feathering state and stops generating electricity, while injecting ballast water into the adjustable float to make the device submerge.

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