A dual-mode rocker plate type wave energy power generation device based on a stepped moon pool and an energy capturing and power generation method

Abstract

This invention relates to a dual-mode rocker-plate wave energy generation device and energy harvesting method based on a stepped moon pool. At least one moon pool is set within a square barge carrier. A rectangular step is set at the bottom of the moon pool, and a rocker-plate float is installed inside the cavity, with a rotating shaft passing through the center of the float. Slots perpendicular to the surface of the square barge carrier are respectively opened on two opposite side walls of the moon pool cavity. A piston rod is slidably connected within the slots, with one end of the piston rod rigidly connected to the end of the adjacent rotating shaft via a crank-connecting rod, and the other end connected to a hydraulic transmission power generation system. The rectangular step within the moon pool amplifies the wave response amplitude, causing the heave-roll dual-degree-of-freedom rocker-plate assembly to generate heave and roll motions. The rotating shaft converts the wave energy accumulated in the expanded moon pool into electrical energy through the hydraulic transmission power generation system. This invention achieves an organic unity of wave focusing effect, efficient energy harvesting, wide-frequency response, and structural durability, providing a reliable technical solution for the large-scale application of wave energy power generation technology.

Description

Technical Field

[0001] This invention relates to a dual-mode rocking plate wave energy generation device and energy harvesting method based on a stepped moon pool, belonging to the field of marine renewable energy technology. Background Technology

[0002] With the continuous growth of global energy demand and the increasing awareness of environmental protection, the development and utilization of renewable energy has become a research hotspot and development trend in the energy field. Ocean wave energy, as a clean and renewable energy form, contains enormous energy potential. It is estimated that the global ocean wave energy reserves are approximately 2-3 TW, making it one of the important sources of future energy supply for humankind, and is of great significance for alleviating dependence on fossil fuels and reducing carbon emissions.

[0003] Currently, wave energy generation technology encompasses various approaches, with oscillating water column, oscillating float, and overtaking types being the three most widely used. However, all three types have technological shortcomings that hinder the development of wave energy generation technology. For oscillating water column devices, the core working principle relies on the reciprocating motion of an air column within a water cavity driven by waves, which in turn drives a turbine to generate electricity. However, due to the compressibility of air, its dynamic response within the cavity introduces a significant phase lag effect, making it difficult to achieve optimal synchronization between the airflow and wave excitation, thus reducing the overall energy capture efficiency. Furthermore, oscillating water column wave energy devices are particularly reliant on the low-order piston response mode of the water column (moon pool). When integrated into coastal structures such as breakwaters, the large cross-section cavity may induce a high-order oscillation response in the moon pool, further reducing energy capture efficiency.

[0004] In contrast, oscillating float-type devices directly drive mechanical or hydraulic energy harvesting systems through the heave, swaying, and rolling motion of the float under wave action, theoretically offering higher secondary conversion efficiency. However, the energy output of such devices is highly dependent on the matching degree between the incident wave frequency and their own natural frequency. In real-world scenarios with variable sea conditions, without effective active tuning or broadband response mechanisms, it is difficult to maintain efficient and stable energy output. Furthermore, the externally exposed moving parts of the oscillating float, such as connecting rods, hinges, or hydraulic cylinders, are highly susceptible to wear or sealing failure in marine environments characterized by sea winds, high salt spray, and strong corrosion. This leads to system functional degradation, significantly increasing maintenance frequency and costs, and reducing the long-term durability of the device.

[0005] While wave-overtaking power generation technology boasts advantages such as fewer moving parts and stable output under high-wave conditions, it relies on waves crossing elevations to enter a reservoir and convert into potential energy, which is then used to generate electricity through a low-head turbine. This imposes minimum threshold requirements on wave height and energy density. Furthermore, the entire process from wave overtaking, water storage, to water release for power generation involves multiple energy losses. Therefore, the application scenarios for wave-overtaking power generation devices are limited to specific sea areas, making large-scale deployment difficult.

[0006] Studies have shown that the fluid motion inside the moon pool exhibits significant resonance characteristics and possesses multiple resonance modes that are easily converted into energy, providing a new approach for wave energy capture. The invention disclosed in CN 110985279 B presents a moon pool-type multi-module wave energy generation system, mainly comprising a semi-submersible platform, an external wave energy generation module, a moon pool wave energy generation module, a power control system, and an anchoring system. The moon pool power generation module and the oscillating buoy power generation module are independent of each other, meaning the moon pool still employs the oscillating water column power generation principle. However, this invention uses a trumpet-shaped moon pool structure and only utilizes the piston resonance of the moon pool to drive the turbine for power generation, which still fails to address the technical limitations of existing technologies.

[0007] In summary, it is necessary to propose a wave energy power generation device that takes into account the wave focusing effect, efficient energy capture, and structural durability in order to solve the above problems. Summary of the Invention

[0008] This invention provides a dual-mode rocking plate wave energy generation device and energy harvesting method based on a stepped moon pool, which achieves the organic unity of wave focusing effect, high-efficiency energy harvesting, wide-band response and structural durability, providing a reliable technical solution for the large-scale application of wave energy power generation technology.

[0009] The technical solution adopted by this invention to solve its technical problem is: A dual-mode rocking plate wave energy generation device based on a stepped moon pool includes a square barge carrier with an inner turret at its bow. The barge carrier is connected to a seabed anchor via a mooring cable, which fixes the square barge carrier in the target sea area and puts it in a wave-facing condition. At least one moon pool is provided inside the square barge carrier; the interior of the moon pool is a cavity that runs through the square barge carrier, and a rectangular step is provided at the bottom of the moon pool, the rectangular step occupying 1 / 3 of the reverse length of the long side of the bottom opening of the moon pool; A heave-roll dual-degree-of-freedom rocker assembly is installed in the inner cavity of the moon pool. It includes a rocker float and a rotating shaft. The rocker float has a wedge-shaped cross section, and its thickness gradually decreases from the center of the rocker float to the two ends. The rotating shaft passes through the center of the rocker float, and the center line of the rotating shaft is perpendicular to the connecting line between the two ends of the rocker float. Vertical square barge carrier cabin surfaces are opened on two opposite side walls of the moon pool cavity. Piston rods are slidably connected in the grooves. One end of the piston rod is rigidly connected to the end of the adjacent rotating shaft through a crank connecting rod. The other end of the piston rod is connected to a hydraulic transmission power generation system. After the rectangular steps inside the moon pool amplify the wave response amplitude, the heave-roll dual-degree-of-freedom rocker assembly generates heave and roll motions. The rotating shaft converts the wave energy accumulated in the expanded moon pool into electrical energy through a hydraulic transmission power generation system. Furthermore, a flow guiding structure is installed on the other side of the rectangular steps at the bottom of the moon pool. It is a plate-like structure that extends towards the seabed and forms an obtuse angle with the outer wall of the moon pool. Furthermore, the rectangular barge carrier has a length-to-width ratio of 5:1, a width-to-depth ratio of 5:3, and a draft-to-depth ratio of 3:2. Furthermore, the rectangular steps located within the moon pool have a length-to-width ratio of 2:1, and their height is between 1 / 5 and 1 / 3 of the water level. The top edge of the rectangular steps is chamfered. Furthermore, the heave-roll dual-degree-of-freedom rocker assembly also includes counterweights, which are respectively installed at both ends of the rocker float; Furthermore, the hydraulic transmission power generation system includes a hydraulic cylinder, hydraulic pipelines, an accumulator, and a hydraulic motor. The other end of the piston rod is embedded in the hydraulic cylinder. The hydraulic cylinder is connected to the accumulator through the hydraulic pipelines. The accumulator is connected to the hydraulic motor. The output shaft of the hydraulic motor is rigidly connected to the input shaft of the generator. Furthermore, two pools were set up inside the square barge carrier; The energy harvesting and power generation method of the dual-mode rocking plate wave energy power generation device based on a stepped moon pool includes the following steps: Step S1: Seawater waves act on the square barge carrier, and after being gathered by the flow guiding structure at the bottom of the moon pool, they are introduced into the moon pool cavity. The rectangular steps in the moon pool excite the moon pool to form a unique piston resonance mode with a half-sine wave shape, so that the wave response amplitude on the surface of the rectangular steps is higher than that at the opening of the moon pool. Step S2: The moon pool resonance response triggered in step S1 drives the heave-roll dual-degree-of-freedom rocker assembly to perform a composite motion. When the main frequency of the seawater waves is close to the natural frequency of the piston resonance, the amplified wave response in the moon pool drives the heave-roll dual-degree-of-freedom rocker assembly to perform a large heave motion along the slide, and at the same time triggers the heave-roll dual-degree-of-freedom rocker assembly to perform a roll motion around the axis of rotation. When the main frequency of the seawater waves is close to the natural frequency of the first-order longitudinal swaying of the moon pool, a large-amplitude left-right sway is generated in the moon pool, driving the heave-roll dual-degree-of-freedom rocker assembly to perform a large-amplitude roll motion, and at the same time triggers the heave-roll dual-degree-of-freedom rocker assembly to perform a heave motion around the axis of rotation. In step S3, the heave-roll dual-degree-of-freedom rocker assembly in step S2 performs a compound motion. The motion is transmitted to the piston rod through the crank connecting rod connected to the end of the rotating shaft, which drives the hydraulic cylinder to operate and outputs high-pressure hydraulic oil. The oil is then transported to the accumulator through the hydraulic pipeline. After the accumulator buffers the pressure fluctuations and stabilizes the hydraulic system pressure, it drives the hydraulic motor to run at high speed. The energy is then converted from wave energy to electrical energy through the generator.

[0010] By employing the above technical solutions, the present invention has the following beneficial effects compared to the prior art: 1. The present invention provides a dual-mode rocker plate wave energy generation device based on a stepped moon pool. The device uses a square barge as a carrier and arranges a stepped moon pool. By optimizing the shape and size of the moon pool chamber, the internal wave motion is enhanced by utilizing the moon pool resonance wave-gathering effect. The heave-roll dual-degree-of-freedom rocker plate assembly is directly set in the moon pool. Wave energy is gathered by the stepped moon pool and directly drives the rocker plate assembly to move. Then, the mechanical energy is converted into electrical energy step by step through the hydraulic transmission system. The phase lag effect caused by the compressibility of air is eliminated, and the wave excitation and energy conversion links are efficiently synchronized. At the same time, the weakening of energy capture efficiency by high-order sway response is avoided. Compared with the traditional oscillating water column device, the energy conversion link is shorter, the loss is lower, and the secondary conversion efficiency is significantly improved. 2. The energy harvesting and power generation method of the dual-mode rocking plate wave energy power generation device based on the stepped moon pool provided by the present invention makes full use of the first two resonant mode characteristics of the stepped moon pool, including the piston resonant mode of half sine wave shape and the first longitudinal sway response. Combined with the heave-roll dual-degree-of-freedom design of the rocking plate assembly, dual-mode adaptive power generation is realized. It can adapt to the actual scenario of changing sea conditions without the need for a complex active tuning mechanism, and greatly broadens the energy harvesting frequency bandwidth of the entire wave energy device. It overcomes the defect of narrow frequency response of traditional oscillating float devices, making it more applicable in actual sea conditions. Attached Figure Description

[0011] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0012] Figure 1 This is a three-dimensional view of the overall structure of the dual-mode rocking plate wave energy generation device based on a stepped moon pool provided by the present invention. Figure 2 This is a top view of the overall structure of the dual-mode rocking plate wave energy generation device based on a stepped moon pool provided by the present invention. Figure 3 This is a cross-sectional view of the moon pool cavity in the dual-mode rocking plate wave energy power generation device based on a stepped moon pool provided by the present invention. Figure 4 This is a schematic diagram of the heave-roll dual-degree-of-freedom rocker assembly structure in the dual-modal rocker wave energy power generation device based on a stepped moon pool provided by the present invention. Figure 5 This is a schematic diagram of the hydraulic transmission power generation system in the dual-mode rocking plate wave energy power generation device based on a stepped moon pool provided by the present invention. Figure 6 This is a schematic diagram of the power generation principle of the hydraulic transmission power generation system in the dual-mode rocking plate wave energy power generation device based on a stepped moon pool provided by the present invention. Figures 7-10 This is a comparison of the motion response (RAO) of a square barge carrier with a stepped moon pool and a barge carrier without a stepped moon pool provided by the invention, where the blue line represents the step and the red line represents the stepless.

[0013] In the diagram: 1 represents a square barge carrier; 2 is the moon pool, 21 is the side wall, 22 is the bottom of the moon pool, 23 is the rectangular step, 24 is the flow guiding structure, 25 is the chamfer, and 26 is the chute; 3 is a rocker assembly with two degrees of freedom, namely heave and pitch; 31 is the rocker float; 32 is the rotating shaft; and 33 is the counterweight. 4 is the hydraulic transmission power generation system, 41 is the piston rod, 42 is the hydraulic cylinder, 43 is the accumulator, 44 is the hydraulic motor, 45 is the generator, and 46 is the hydraulic pipeline. 5 is the inner turret. Detailed Implementation

[0014] The present invention will now be described in further detail with reference to the accompanying drawings. In the description of this application, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of the present invention.

[0015] As described in the background section, the core shortcomings of existing technologies for oscillating water column devices lie in the inefficiency and structural complexity of the aerodynamic conversion process, while oscillating float devices are limited by insufficient mechanical durability in harsh marine environments and narrow dynamic response bandwidth. Even the most advanced moonpool technology essentially still employs the traditional oscillating water column power generation principle.

[0016] To address the challenges of existing technologies, this application provides a dual-mode rocker plate wave energy generation device based on a stepped moon pool. The innovation of its entire structure lies in the combination of the stepped moon pool with a heave-roll dual-degree-of-freedom rocker plate assembly 3 with a built-in moon pool cavity.

[0017] The entire structure is as follows Figures 1-2As shown, the structure includes a square barge carrier 1 with an internal turret 5 at its bow, connected to a seabed anchor via mooring cables. This allows for precise positioning of the square barge carrier, while the weathervane effect enables it to rotate 360° with the wind and waves, ensuring the bow is always in a wave-facing position. Compared to irregularly shaped carriers, the square structure is simpler to manufacture, has lower construction costs, and offers more flexible space for the moon pool 2. At least one moon pool 2 is provided within the square barge carrier; preferably... Figure 2 As can be seen from the perspective, this application sets up a moon pool in the front and rear halves of the square barge carrier, fully considering the actual working conditions and adopting a two-moon pool design scheme.

[0018] Regarding the specific structure of the moon pool, its interior is a cavity penetrating the square barge carrier. A rectangular step 23 is set at the bottom 22 of the moon pool, and the rectangular step occupies 1 / 3 of the reverse length of the long side of the bottom opening of the moon pool. The stepped moon pool has significant nonlinear resonance response characteristics. Combined with the width-to-length ratio design of this application, it is very easy to excite first-order sway response superharmonic resonance, broadening the energy absorption frequency band of the entire device. The wave response amplitude on the surface of the step is significantly higher than that at the opening of the moon pool, which gathers and amplifies the dispersed wave energy, providing a more powerful power output for the rocker assembly. The heave-roll dual-degree-of-freedom rocker assembly set in the inner cavity of the moon pool is a way to directly capture energy by arranging the float in the moon pool, avoiding the phase lag effect caused by traditional pneumatic worm gear power generation, and improving the energy conversion efficiency. As an energy-concentrating cavity, the stepped moon pool has a significant difference in response amplitude at its front and rear ends in the piston resonance mode. It can drive the float to sway or to generate large-amplitude roll. Therefore, the dual-mode complementarity improves the stability of the output power.

[0019] To enhance the wave energy concentration effect of the stepped moon pool, this application also installs a flow guiding structure 24 on the opposite side of the rectangular step at the bottom of the moon pool. Figure 3 As shown, it is a plate-like structure extending towards the seabed and forming an obtuse angle with the outer wall 21 of the moon pool. This guides dispersed waves from the outside of the barge into the moon pool cavity, reducing energy loss caused by wave flow and increasing the total wave energy entering the moon pool. The obtuse angle design prevents the guiding structure from creating rigid obstruction to the waves, reducing structural wear caused by wave impact, while allowing waves to enter the moon pool smoothly, ensuring the stability of resonance within the moon pool. Additionally, a chamfer 25 is provided along the upper edge of the rectangular step to weaken the viscous energy dissipation caused by fluid separation.

[0020] As mentioned above, this application preferably uses two moon pools, which can achieve double the wave energy gathering channels. When the rocker plate assembly is installed in the moon pool, the total power generation can be directly increased. Of course, the design of two moon pools can also complement each other. If one of them is temporarily unable to work due to a malfunction, the other can continue to generate electricity, avoiding the risk of downtime.

[0021] The heave-roll dual-DOF rocker assembly needs to generate both heave and roll simultaneously. Therefore, the heave-roll dual-DOF rocker assembly provided in this application uses a rocker mechanism as the energy harvesting unit, which has few moving parts and a simple structure. Specifically, it includes a rocker float 31 and a rotating shaft 32. Figure 4 As shown, the rocking buoy has a wedge-shaped cross-section, with its thickness gradually decreasing from the center to both ends (thicker in the middle and thinner at the edges, with the greatest thickness at the pivot). When impacted by waves, the thinner ends can move quickly with the waves, causing the rocking buoy to rotate around the pivot, ensuring that the rocking assembly fully follows the wave fluctuations in the moon pool and maximizes wave energy capture. The pivot passes through the center of the rocking buoy, and the center line of the pivot is perpendicular to the connecting line between the two ends of the rocking buoy. On the two opposite side walls 21 of the moon pool cavity, vertical grooves 26 are respectively opened on the surface of the square barge carrier cabin. A piston rod 41 is slidably connected in the groove. One end of the piston rod is rigidly connected to the end of the adjacent pivot through a crank connecting rod, and the other end of the piston rod is connected to the hydraulic transmission power generation system 4. The crank-connecting rod flexibly converts the rotational motion of the shaft into the linear motion of the piston rod, transforming the irregular motion of the rocker into the continuous, regular motion of the piston rod. The rocker float, via the crank-connecting rod, can sway along the groove in response to the piston rod, and can also oscillate around the shaft in response to the moon pool, thus maximizing the conversion of wave energy accumulated in the moon pool into mechanical energy. Furthermore, a drag-reducing coating is applied to the surface of the rocker float, and counterweights 33 are installed at both ends of the float. This reduces motion resistance, improves the efficiency of mechanical energy conversion, reduces component stress losses, and significantly enhances the long-term durability of the device in harsh marine environments.

[0022] In this application, the hydraulic transmission power generation system maximizes the conversion of wave energy into electrical energy; preferably, such as... Figure 5 As shown, it includes a hydraulic cylinder 42, a hydraulic pipeline 46, an accumulator 43, and a hydraulic motor 44. The other end of the piston rod is embedded in the hydraulic cylinder. The hydraulic cylinder is connected to the accumulator through the hydraulic pipeline. The accumulator is connected to the hydraulic motor. The output shaft of the hydraulic motor is rigidly connected to the input shaft of the generator 45.

[0023] Since this application utilizes the moon pool resonance wave-gathering effect to enhance internal wave motion, and employs a rocking buoy to directly absorb the swaying response of the bath, achieving the highest energy conversion efficiency is closely related to the dimensions of the moon pool and the square barge carrier. This application preferably sets the length-to-width ratio of the square barge carrier to 5:1, the width-to-depth ratio to 5:3, and the draft-to-depth ratio to 3:2. The rectangular steps located within the moon pool have a length-to-width ratio of 2:1, and their height is between 1 / 5 and 1 / 3 of the draft. The length-to-width ratio is adapted to the wind vane rotation requirements of the inner turret, reducing water resistance during rotation; the width-to-depth ratio and draft-to-depth ratio ensure that the carrier is not prone to significant heaving / rolling in waves, and the draft is reasonable, preventing damage to the bottom of the moon pool from wave impacts while allowing the flow-guiding structure and steps to fully engage with the waves, and providing ample space for the internal installation of hydraulic systems, generators, and other equipment.

[0024] This application further provides a method for generating electricity using the dual-mode rocking plate wave energy power generation device based on a stepped moon pool, including the following steps: Step S1: Seawater waves act on the square barge carrier, and after being gathered by the flow guiding structure at the bottom of the moon pool, they are introduced into the moon pool cavity. The rectangular steps in the moon pool excite the moon pool to form a unique piston resonance mode with a half-sine wave shape, so that the wave response amplitude on the surface of the rectangular steps is higher than that at the opening of the moon pool. Step S2: The moon pool resonance response excited in step S1 drives the heave-roll dual-degree-of-freedom rocker assembly to perform a composite motion. When the main frequency of the seawater waves approaches the piston resonance natural frequency... At that time, the amplified wave response in the moon pool drives the heave-roll dual-degree-of-freedom rocker assembly to perform large-amplitude heave motion along the slide, while simultaneously exciting the heave-roll dual-degree-of-freedom rocker assembly to perform roll motion around the axis of rotation; when the main frequency of the seawater waves approaches the first-order longitudinal oscillation natural frequency of the moon pool... At that time, a large left-right sway occurs in the moon pool, which drives the heave-roll dual-degree-of-freedom rocker assembly to perform a large-amplitude roll motion, and at the same time excites the heave-roll dual-degree-of-freedom rocker assembly to perform a heave motion around the axis of rotation. As can be seen from this step, the rocker assembly provided in this application can perform both heaving and pitching motions simultaneously. The vertical resonance of the moon pool drives the rocker to sway significantly and also pitch, while the horizontal swaying of the moon pool drives the rocker to pitch significantly and also sway significantly, thus achieving all-round capture of amplified wave energy within the moon pool.

[0025] In step S3, the heave-roll dual-degree-of-freedom rocker assembly in step S2 performs a compound motion. The motion is transmitted to the piston rod through the crank connecting rod connected to the end of the rotating shaft, which drives the hydraulic cylinder to operate and outputs high-pressure hydraulic oil. The oil is then transported to the accumulator through the hydraulic pipeline. After the accumulator buffers the pressure fluctuations and stabilizes the hydraulic system pressure, it drives the hydraulic motor to run at high speed. The energy is then converted from wave energy to electrical energy through the generator.

[0026] To verify the feasibility of the dual-mode rocker plate wave energy generation device based on a stepped moon pool provided in this application, experimental verification was conducted. Setting up two moon pools is preferred. The rocker plate assembly of the left moon pool in the figure is defined as rocker plate 1, and the rocker plate assembly of the right moon pool is defined as rocker plate 2. Figures 7-10 A comparison of the motion response (RAO) of a square barge carrier with and without a stepped moon pool (blue line represents stepped, red line represents without stepped). Figure 7 As shown, the heave amplitude of a square barge with a stepped moon pool is much greater than that of a barge without a stepped moon pool. Figure 8 In Figure 8a, the sway amplitude of rocker 1 is compared, and in Figure 8b, the sway amplitude of rocker 2 is compared. It is clear that, whether it is rocker 1 or rocker 2, the sway amplitude of the rocker with the stepped moon pool is much greater than that of the rocker without the stepped moon pool. Figure 9 As shown, the pitching frequency band of a square barge with a stepped moon pool is much greater than that of a barge without a stepped moon pool. Figure 10 In Figure 10a, the pitch frequency band of rocker 1 is compared, and in Figure 8b, the pitch frequency band of rocker 2 is compared. It is clear that, whether it is rocker 1 or rocker 2, the pitch frequency band of the rocker with the stepped moon pool is much larger than that of the rocker without the stepped moon pool.

[0027] Those skilled in the art will understand that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0028] The meaning of "and / or" as used in this application includes situations where each exists alone or both exist simultaneously.

[0029] The term "connection" as used in this application can mean a direct connection between components or an indirect connection between components through other components.

[0030] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A dual-mode rocking plate wave energy generation device based on a stepped moon pool, characterized in that: It includes a square barge carrier with an internal turret at its bow, which is connected to an underwater anchor via mooring cables to fix the square barge carrier in the target sea area and in a wave-facing condition; At least one moon pool is provided inside the square barge carrier; the interior of the moon pool is a cavity that runs through the square barge carrier, and a rectangular step is provided at the bottom of the moon pool, the rectangular step occupying 1 / 3 of the reverse length of the long side of the bottom opening of the moon pool; A heave-roll dual-degree-of-freedom rocker assembly is installed in the inner cavity of the moon pool. It includes a rocker float and a rotating shaft. The rocker float has a wedge-shaped cross section, and its thickness gradually decreases from the center of the rocker float to the two ends. The rotating shaft passes through the center of the rocker float, and the center line of the rotating shaft is perpendicular to the connecting line between the two ends of the rocker float. Vertical square barge carrier cabin surfaces are opened on two opposite side walls of the moon pool cavity. Piston rods are slidably connected in the grooves. One end of the piston rod is rigidly connected to the end of the adjacent rotating shaft through a crank connecting rod. The other end of the piston rod is connected to a hydraulic transmission power generation system. The rectangular steps inside the moon pool amplify the wave response amplitude, and the heave-roll dual-degree-of-freedom rocker assembly generates heave and roll motions. The rotating shaft converts the wave energy accumulated in the expanded moon pool into electrical energy through a hydraulic transmission power generation system.

2. The dual-mode rocking plate wave energy generation device based on a stepped moon pool according to claim 1, characterized in that: A flow guiding structure is installed on the other side of the rectangular steps at the bottom of the moon pool. It is a plate-like structure that extends towards the seabed and forms an obtuse angle with the outer wall of the moon pool.

3. The dual-mode rocking plate wave energy generation device based on a stepped moon pool according to claim 1, characterized in that: The rectangular barge has a length-to-width ratio of 5:1, a width-to-depth ratio of 5:3, and a draft-to-depth ratio of 3:

2.

4. The dual-mode rocking plate wave energy generation device based on a stepped moon pool according to claim 1, characterized in that: The rectangular steps located in the moon pool have a length-to-width ratio of 2:1, and the height of the rectangular steps is between 1 / 5 and 1 / 3 of the water level. The upper edge of the rectangular step is chamfered.

5. The dual-mode rocking plate wave energy generation device based on a stepped moon pool according to claim 1, characterized in that: The heave-roll dual-degree-of-freedom rocker assembly also includes counterweights, which are respectively installed at both ends of the rocker float.

6. The dual-mode rocking plate wave energy generation device based on a stepped moon pool according to claim 1, characterized in that: The hydraulic transmission power generation system includes a hydraulic cylinder, hydraulic pipelines, an accumulator, and a hydraulic motor. The other end of the piston rod is embedded in the hydraulic cylinder. The hydraulic cylinder is connected to the accumulator through the hydraulic pipelines. The accumulator is connected to the hydraulic motor. The output shaft of the hydraulic motor is rigidly connected to the input shaft of the generator.

7. The dual-mode rocking plate wave energy generation device based on a stepped moon pool according to claim 1, characterized in that: Two pools were set up inside the square barge carrier.

8. A method for capturing and generating energy based on a dual-mode rocking plate wave energy power generation device based on a stepped moon pool as described in any one of claims 1-7, characterized in that: Includes the following steps: Step S1: Seawater waves act on the square barge carrier, and after being gathered by the flow guiding structure at the bottom of the moon pool, they are introduced into the moon pool cavity. The rectangular steps in the moon pool excite the moon pool to form a unique piston resonance mode with a half-sine wave shape, so that the wave response amplitude on the surface of the rectangular steps is higher than that at the opening of the moon pool. Step S2: The moon pool resonance response triggered in step S1 drives the heave-roll dual-degree-of-freedom rocker assembly to perform a composite motion. When the main frequency of the seawater waves is close to the natural frequency of the piston resonance, the amplified wave response in the moon pool drives the heave-roll dual-degree-of-freedom rocker assembly to perform a large heave motion along the slide, and at the same time triggers the heave-roll dual-degree-of-freedom rocker assembly to perform a roll motion around the axis of rotation. When the main frequency of the seawater waves is close to the natural frequency of the first-order longitudinal swaying of the moon pool, a large-amplitude left-right sway is generated in the moon pool, driving the heave-roll dual-degree-of-freedom rocker assembly to perform a large-amplitude roll motion, and at the same time triggers the heave-roll dual-degree-of-freedom rocker assembly to perform a heave motion around the axis of rotation. In step S3, the heave-roll dual-degree-of-freedom rocker assembly in step S2 performs a compound motion. The motion is transmitted to the piston rod through the crank connecting rod connected to the end of the rotating shaft, which drives the hydraulic cylinder to operate and outputs high-pressure hydraulic oil. The oil is then transported to the accumulator through the hydraulic pipeline. After the accumulator buffers the pressure fluctuations and stabilizes the hydraulic system pressure, it drives the hydraulic motor to run at high speed. The energy is then converted from wave energy to electrical energy through the generator.

Images