Dual-frequency high-efficiency energy harvesting method of spring pendulum float wave energy power generation device

Abstract

This invention relates to the field of wave energy generation, and more particularly to a dual-frequency high-efficiency energy harvesting method for a spring pendulum wave energy generator. The energy harvesting method includes the following steps: the spring pendulum wave energy generator enters the working state and directly contacts seawater, moving in undulating motion with the waves; the two directional degrees of freedom of the spring pendulum wave energy generator are adjusted; the spring pendulum wave energy generator uses a swing arm to adjust the resonant frequency of the oscillation degree of freedom of the float; the spring pendulum wave energy generator uses the resonant frequency of the hemispherical float and the spring-adjusted float along the radial degree of freedom of the long swing arm; a spring is added to the swing arm to make it a nonlinear spring pendulum structure, and its internal resonance characteristics are used to realize the mutual switching of the float's kinetic energy between the oscillation and radial degrees of freedom.

Description

Technical fields:

[0001] This invention relates to a dual-frequency high-efficiency energy harvesting method for a spring pendulum float wave energy power generation device. Background technology:

[0002] Promoting energy transformation and empowering green development are inherent requirements for promoting high-quality development and a common mission of the international community today. Wave energy, as the most important part of marine renewable energy, is widely distributed in major sea areas. It has the characteristics of high energy density, low difficulty of acquisition, and strong exploitability. It plays an important role in alleviating the energy crisis, reducing environmental pollution, solving the electricity demand in deep and far sea areas, and developing marine island resources. It has broad development prospects and profound application significance.

[0003] With the development of wave energy technology, the energy harvesting methods of traditional wave energy power generation devices are too simplistic and the energy harvesting efficiency is low, resulting in excessively low energy capture efficiency for most wave energy power generation devices, which cannot meet the needs of practical applications. This low energy capture efficiency leads to high power generation costs, making it difficult for wave energy power generation devices to gain a competitive advantage in the renewable energy market, including wind and solar power, and severely hindering the industrialization process.

[0004] Because traditional heave or pendulum-type single-degree-of-freedom float devices can only reach resonance at a single frequency, their bandwidth for efficiently capturing wave energy is narrow. Once the wave frequency deviates from the device's resonant frequency, the capture efficiency drops significantly. Such traditional wave energy generation devices can only be adapted to very specific wave conditions.

[0005] In actual marine environments, ocean waves are mostly a mixture of wind and swell, with wind waves and swells overlapping each other and exhibiting strong seasonal variations. Wind wave periods are typically 3-5 seconds, while swell periods are greater than 10 seconds. Wave energy is concentrated around two frequencies, resulting in a bimodal wave spectrum. However, the non-replaceability and single-wave-condition adaptability of single-frequency float devices mean that wave energy outside the resonant frequency cannot be effectively captured. A significant amount of wave energy concentrated near the other spectral peak frequency is lost, leading to a waste of wave energy resources and impacting the overall wave energy power generation efficiency. Summary of the Invention:

[0006] This invention provides a dual-frequency high-efficiency energy harvesting method for a spring pendulum float wave energy power generation device. The method is rationally designed and can harvest energy through dual-degree-of-freedom motion response under bimodal wave conditions where wind and swells coexist. It achieves efficient capture of dual-frequency wave energy through dual-frequency resonance response, effectively improving the device's adaptability to real-world wave conditions and the power generation efficiency of the wave energy power generation device. It can be applied to a wide range of sea areas in my country with mixed wind and swell waves. Furthermore, the power generation process does not produce carbon dioxide or any pollutants, thus avoiding pollution of the marine and atmospheric environments. It can be freely mounted on the platform beam according to user needs, reducing its own volume and sea area footprint while fully utilizing the multi-frequency wave energy resources of wind and swells, maximizing the use of sea space and energy, and solving the problems existing in the prior art.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0008] A dual-frequency high-efficiency energy harvesting method for a spring pendulum float wave energy power generation device, the energy harvesting method comprising the following steps:

[0009] S1, the spring pendulum wave energy generator enters the working state, directly contacting the seawater and moving up and down with the waves to convert wave energy into mechanical energy held by the spring pendulum wave energy generator.

[0010] S2 adjusts the two degrees of freedom of motion of the spring pendulum float wave energy generator in two directions, suitable for two different wave frequencies, so that the spring pendulum float wave energy generator can generate a resonant response at both wave frequencies;

[0011] S3, the spring pendulum float wave energy power generation device uses a pendulum arm to adjust the resonant frequency of the float's swing degree of freedom, so as to achieve matching with the low frequency peak frequency. It mainly captures wave energy near the low frequency peak by utilizing the oscillation of the float around the swing axis under the action of the wave.

[0012] S4, the spring pendulum float wave energy power generation device uses the resonant frequency of the hemispherical float and the spring-adjustable float along the radial degree of freedom of the long pendulum arm to achieve matching with the high frequency peak frequency. It mainly captures wave energy near the high frequency peak by utilizing the radial motion of the float under the wave force.

[0013] S5 adds a spring to the swing arm, making it a nonlinear spring pendulum structure. Utilizing its internal resonance characteristics, it realizes the mutual switching of the float's kinetic energy between the two degrees of freedom of oscillation and radial direction, converting the wave energy that is difficult to capture to the other degree of freedom for capture, and further improving the energy capture efficiency of the device.

[0014] The spring pendulum wave energy generation device includes a rotating shaft, a spring swing arm, a connecting shaft, a swing hydraulic cylinder, a linear hydraulic cylinder, and a hemispherical float that are configured in a matching manner. There are two swing hydraulic cylinders and two spring swing arms. The rotating shafts of the swing hydraulic cylinders are rigidly connected to the rotating shaft respectively. The upper part of the spring swing arm is fixed to the rotating shaft, and the lower part of the spring swing arm passes through the hemispherical float and is rigidly fixed to the connecting shaft.

[0015] The upper part of the linear hydraulic cylinder is connected to the rotating shaft, and the lower part of the linear hydraulic cylinder is connected to the hemispherical float so that the hemispherical float will swing and move radially when subjected to waves.

[0016] When the float oscillates, it drives the spring swing arm to oscillate together, which in turn drives the swing hydraulic cylinder and the rear generator to generate electricity. When the float moves radially, it moves along the spring swing arm, which drives the linear hydraulic cylinder and the rear generator to generate electricity.

[0017] When the float is subjected to the horizontal force of the wave at its equilibrium position, the float moves around its axis to drive the oscillating hydraulic cylinder to convert the mechanical energy of the float's oscillation into electrical energy. When the float is subjected to the vertical force of the wave at its equilibrium position, it drives the linear hydraulic cylinder to convert the mechanical energy of the radial motion into electrical energy. After a certain rotation angle is generated, the float will oscillate and move radially under the combined action of the horizontal and vertical forces of the wave, driving the oscillating hydraulic cylinder and the linear hydraulic cylinder to gain energy.

[0018] Multiple bolt holes are provided on the swing hydraulic cylinder to fix the swing hydraulic cylinder to the hemispherical float.

[0019] The spring pendulum float wave energy generation device can be installed on a platform or crossbeam to achieve integrated installation of the device.

[0020] This invention employs the aforementioned structure, utilizing a spring-loaded pendulum wave energy generator that moves with the undulating motion of waves to convert wave energy into mechanical energy held by the device, which is then converted into electrical energy through an energy conversion system. The spring-loaded pendulum wave energy generator uses a swing arm to adjust the resonant frequency of the float's oscillation degree of freedom, achieving matching with the low-frequency peak frequency. By utilizing the float's oscillation around its swing axis under wave force, it primarily captures wave energy near the low-frequency peak. Furthermore, the spring-loaded pendulum wave energy generator uses a hemispherical float and a spring to adjust the resonant frequency of the float's radial degree of freedom along the long swing arm, achieving matching with the high-frequency peak frequency. By utilizing the float's radial motion under wave force, it primarily captures wave energy near the high-frequency peak. This design offers advantages such as simplicity, high efficiency, energy saving, and environmental friendliness. Attached image description:

[0021] Figure 1 This is a schematic diagram of the structure of the spring pendulum float wave power generation device of the present invention.

[0022] Figure 2 for Figure 1 The main view.

[0023] Figure 3 for Figure 1 Side view.

[0024] Figure 4 for Figure 1 Top view.

[0025] Figure 5 This is a schematic diagram of the motion of the spring pendulum float wave power generation device of the present invention.

[0026] Figure 6 This is a schematic diagram of the motion of the float of the present invention under a horizontal force.

[0027] Figure 7 This is a schematic diagram illustrating the motion of the float of the present invention under vertical force.

[0028] In the diagram, 1 is the rotating shaft, 2 is the spring swing arm, 3 is the connecting shaft, 4 is the swing hydraulic cylinder, 5 is the linear hydraulic cylinder, and 6 is the hemispherical float. Detailed implementation method:

[0029] To clearly illustrate the technical features of this solution, the invention will be described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0030] like Figure 1-7 As shown, a dual-frequency high-efficiency energy harvesting method for a spring pendulum float wave energy power generation device includes the following steps:

[0031] S1, the spring pendulum wave energy generator enters the working state, directly contacting the seawater and moving up and down with the waves to convert wave energy into mechanical energy held by the spring pendulum wave energy generator.

[0032] S2 adjusts the two degrees of freedom of motion of the spring pendulum float wave energy generator in two directions, suitable for two different wave frequencies, so that the spring pendulum float wave energy generator can generate a resonant response at both wave frequencies;

[0033] S3, the spring pendulum float wave energy power generation device uses a pendulum arm to adjust the resonant frequency of the float's swing degree of freedom, so as to achieve matching with the low frequency peak frequency. It mainly captures wave energy near the low frequency peak by utilizing the oscillation of the float around the swing axis under the action of the wave.

[0034] S4, the spring pendulum float wave energy power generation device uses the resonant frequency of the hemispherical float and the spring-adjustable float along the radial degree of freedom of the long pendulum arm to achieve matching with the high frequency peak frequency. It mainly captures wave energy near the high frequency peak by utilizing the radial motion of the float under the wave force.

[0035] S5 adds a spring to the swing arm, making it a nonlinear spring pendulum structure. Utilizing its internal resonance characteristics, it realizes the mutual switching of the float's kinetic energy between the two degrees of freedom of oscillation and radial direction, converting the wave energy that is difficult to capture to the other degree of freedom for capture, and further improving the energy capture efficiency of the device.

[0036] The spring pendulum wave energy generation device includes a rotating shaft 1, a spring pendulum arm 2, a connecting shaft 3, a swing hydraulic cylinder 4, a linear hydraulic cylinder 5, and a hemispherical float 6, which are arranged in a matching manner. There are two swing hydraulic cylinders 4 and two spring pendulum arms 2. The rotating shaft of the swing hydraulic cylinder 4 is rigidly connected to the rotating shaft 1 respectively. The upper part of the spring pendulum arm 2 is fixed to the rotating shaft 1, and the lower part of the spring pendulum arm 2 passes through the hemispherical float 6 and is rigidly fixed to the connecting shaft 3.

[0037] The upper part of the linear hydraulic cylinder 5 is connected to the rotating shaft 1, and the lower part of the linear hydraulic cylinder 5 is connected to the hemispherical float 6, so that when subjected to waves, the hemispherical float 6 will swing and move radially.

[0038] When the float swings, it drives the spring swing arm 2 to swing together, and at the same time drives the swing hydraulic cylinder 4 and the rear generator to generate electricity; when the float moves radially, it will move along the spring swing arm 2 to drive the linear hydraulic cylinder and the rear generator to generate electricity.

[0039] When the float is subjected to the horizontal force of the wave at its equilibrium position, the float moves around the pivot 1 to drive the oscillating hydraulic cylinder 4 to convert the mechanical energy of the float's oscillation into electrical energy; when the float is subjected to the vertical force of the wave at its equilibrium position, it drives the linear hydraulic cylinder 5 to convert the mechanical energy of the radial motion into electrical energy; after a certain rotation angle is generated, the float will oscillate and move radially under the combined action of the horizontal and vertical forces of the wave, driving the oscillating hydraulic cylinder and the linear hydraulic cylinder to gain energy.

[0040] Multiple bolt holes are provided on the swing hydraulic cylinder 4 to fix the swing hydraulic cylinder 4 to the hemispherical float 6.

[0041] The spring pendulum float wave energy generation device can be installed on a platform or crossbeam to achieve integrated installation of the device.

[0042] The working principle of the dual-frequency high-efficiency energy harvesting method of the spring pendulum float wave energy power generation device in this embodiment of the invention is as follows: Under the coordinated action of multiple functional components, it can perform dual-degree-of-freedom motion resonance response energy harvesting under the double-peak spectrum wave conditions where wind waves and swells coexist in actual sea conditions. It achieves efficient capture of dual-frequency wave energy through dual-frequency resonance response, effectively improving the adaptability of the device to actual sea conditions and the power generation efficiency of the wave energy power generation device. It can be applied to a wide range of sea areas in my country with mixed wind and swell waves. At the same time, it does not produce carbon dioxide or any pollutants during the power generation process, and will not pollute the marine and atmospheric environment. It can be freely loaded on the platform beam according to user needs. While reducing its own volume, it can make full use of the multi-frequency wave energy resources of wind and swell waves, reduce the sea area occupied by the device, and maximize the use of sea space and energy.

[0043] Faced with increasingly severe climate problems and energy crises, the development of clean and renewable energy has become a global consensus. Ocean renewable energy, which contains enormous energy reserves, has received widespread attention; wave energy is a specific form of ocean energy and one of the most important energy sources in the ocean. Its development and utilization are crucial for alleviating the energy crisis and reducing environmental pollution. Therefore, the wave energy power generation device in this application can fully develop and utilize wave energy resources.

[0044] The overall scheme includes the following steps for energy generation: The spring-pendulum float wave energy generator enters its working state, directly contacting seawater and undulating with the waves to convert wave energy into mechanical energy held by the spring-pendulum float wave energy generator; the two degrees of freedom of motion of the spring-pendulum float wave energy generator are adjusted to suit two different wave frequencies, so that the spring-pendulum float wave energy generator can generate a resonant response at both wave frequencies; the spring-pendulum float wave energy generator uses a swing arm to adjust the resonant frequency of the float's swinging degree of freedom, achieving matching with the low-frequency peak frequency, utilizing the float's... The oscillation around the pendulum axis under wave force mainly captures wave energy near the low-frequency peak. The spring pendulum float wave energy power generation device uses a hemispherical float to adjust the resonant frequency of the float along the radial degree of freedom of the long pendulum arm to achieve matching with the high-frequency peak frequency. By utilizing the radial motion of the float under wave force, it mainly captures wave energy near the high-frequency peak. A spring is added to the pendulum arm to make it a nonlinear spring pendulum structure. Utilizing its internal resonance characteristics, the kinetic energy of the float can be switched between the two degrees of freedom of oscillation and radial direction. This converts the wave energy that is difficult to capture to the other degree of freedom for capture, further improving the energy capture efficiency of the device.

[0045] Specifically, the float is used as the energy harvester. The float is in direct contact with the seawater and moves up and down with the waves, converting wave energy into mechanical energy held by the float. Therefore, the greater the amplitude of the float's wave motion, the better its energy harvesting effect.

[0046] When the wave frequency matches the float's own natural frequency, the two resonate, and the float captures the maximum wave energy. Since the specific resonant frequencies of the floats are different, when the float has two degrees of freedom, it can generate a resonant response in one degree of freedom at each of the two wave frequencies, achieving a highly efficient energy capture state. At the same time, its efficient capture bandwidth in the entire wave spectrum is also broadened.

[0047] This application combines the radial and oscillating degrees of freedom of a spring pendulum float to provide a dual-frequency high-efficiency energy harvesting method for wave energy, and applies it to bimodal spectrum sea areas. However, according to actual wave resource surveys, the low-frequency peak frequency in bimodal spectrum sea areas is mostly below 0.5 rad / s, which is very low. For small and medium-sized floats, it is difficult to achieve the required resonant frequency for their own heave or pitch degrees of freedom. For large floats, it is difficult to generate electricity under conditions of low-intensity waves.

[0048] Based on this, this application uses a long swing arm to reduce the resonant frequency of the float's swing degree of freedom, achieving matching with the low-frequency peak frequency, so that the float swings around the swing axis under the wave force, mainly capturing wave energy near the low-frequency peak; a hemispherical float is used to adjust the resonant frequency of the float's radial degree of freedom along the long swing arm, achieving matching with the high-frequency peak frequency, and utilizing the radial motion of the float under the wave force, mainly capturing wave energy near the high-frequency peak.

[0049] In order to enable the kinetic energy of the float to be converted between the two degrees of freedom of oscillation and radial direction, a spring is added to the float swing arm, so that the entire swing arm constitutes a nonlinear spring pendulum structure, which transfers the wave energy that is difficult to capture to the other degree of freedom, thereby further improving the energy capture efficiency of the device.

[0050] The thickness and density of a nonlinear spring vary from top to bottom, and its elastic coefficient is not a fixed value, making it well-suited for complex and ever-changing wave applications.

[0051] The wave energy generation device using a spring pendulum float includes a hemispherical float, spring swing arms, linear hydraulic cylinders, oscillating hydraulic cylinders, a rotating shaft, and a connecting shaft. The two spring swing arms are rigidly connected to the rotating shaft at the top and pass through the hemispherical float at the bottom before being fixed by the connecting shaft, while also serving as a limiting mechanism. The linear hydraulic cylinders are rigidly connected to the rotating shaft and the upper surface of the hemispherical float, respectively. Both ends of the rotating shaft are rigidly connected to the rotating shaft of the oscillating hydraulic cylinder. The oscillating cylinder has multiple bolt holes, which can be bolted to the float to be connected.

[0052] Under the excitation of waves, the float has two degrees of freedom: radial motion along the swing arm and oscillation around the axis of rotation. During radial motion, the nonlinear spring on the upper part of the float is compressed, and the linear hydraulic cylinder is driven to capture wave energy. During oscillation, the oscillating hydraulic cylinder is driven to capture wave energy. The rear ends of the linear hydraulic cylinder and the oscillating hydraulic cylinder are connected to the hydraulic motor and generator through a hydraulic circuit to drive the generator to generate electricity.

[0053] This application can fully capture wind and swell energy through the movement of the spring pendulum float device. It can be applied to a wide range of sea areas in my country with mixed wind and swell waves, achieving efficient energy capture in sea areas with dual-frequency wave energy composition, and solving the problem of low capture efficiency of wave energy power generation devices in actual sea conditions.

[0054] It should be noted that this application does not produce any carbon dioxide or pollutants during the power generation process, does not pollute the marine and atmospheric environment, has a simple overall structure, is easy to manufacture, and has a flexible installation method. The device can be freely installed on different structures such as platform beams according to user needs, so as to achieve integrated installation of the device.

[0055] In summary, the dual-frequency high-efficiency energy harvesting method of the spring pendulum float wave energy generation device in this embodiment of the invention can achieve dual-degree-of-freedom motion resonance response energy harvesting under the double-peak spectrum wave conditions where wind waves and swells coexist in actual sea conditions. It achieves efficient capture of dual-frequency wave energy through dual-frequency resonance response, effectively improving the adaptability of the device to actual sea conditions and the power generation efficiency of the wave energy generation device. It can be applied to a wide range of sea areas in my country with mixed wind and swell waves. At the same time, it does not produce carbon dioxide or any pollutants during the power generation process, and will not pollute the marine and atmospheric environment. It can be freely mounted on the platform beam according to user needs. While reducing its own volume, it can make full use of the multi-frequency wave energy resources of wind and swell waves, reduce the sea area occupied by the device, and maximize the use of sea space and wave energy.

[0056] The above specific embodiments should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, any alternative improvements or modifications made to the embodiments of the present invention shall fall within the scope of protection of the present invention.

[0057] Any aspects of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A dual frequency high efficiency energy harvesting method for a spring pendulum float wave energy device, characterized in that, The energy acquisition method includes the following steps: S1, the spring pendulum wave energy generator enters the working state, directly contacting the seawater and moving up and down with the waves to convert wave energy into mechanical energy held by the spring pendulum wave energy generator. S2 adjusts the two degrees of freedom of motion of the spring pendulum float wave energy generator in two directions, suitable for two different wave frequencies, so that the spring pendulum float wave energy generator can generate a resonant response at both wave frequencies; S3, the spring pendulum float wave energy power generation device uses a pendulum arm to adjust the resonant frequency of the float's swing degree of freedom, so as to achieve matching with the low frequency peak frequency. It mainly captures wave energy near the low frequency peak by utilizing the oscillation of the float around the swing axis under the action of the wave. S4, the spring pendulum float wave energy power generation device uses the resonant frequency of the hemispherical float and the spring-adjustable float along the radial degree of freedom of the long pendulum arm to achieve matching with the high frequency peak frequency. It mainly captures wave energy near the high frequency peak by utilizing the radial motion of the float under the action of the wave. S5, a spring is added to the swing arm to make it a nonlinear spring pendulum structure. By utilizing its internal resonance characteristics, the kinetic energy of the float can be switched between the two degrees of freedom of swing and radial direction. The wave energy that is difficult to capture can be converted to another degree of freedom for capture, thereby further improving the energy capture efficiency of the device. The spring pendulum wave energy generation device includes a rotating shaft, a spring swing arm, a connecting shaft, a swing hydraulic cylinder, and a hemispherical float that are configured in a matching manner. There are two swing hydraulic cylinders and two spring swing arms. The rotating shafts of the swing hydraulic cylinders are rigidly connected to the rotating shaft respectively. The upper part of the spring swing arm is fixed to the rotating shaft, and the lower part of the spring swing arm passes through the hemispherical float and is rigidly fixed to the connecting shaft.

2. The dual-frequency high-efficiency energy harvesting method for a spring pendulum float wave energy power generation device according to claim 1, characterized in that: The spring pendulum wave energy generation device also includes a linear hydraulic cylinder, the upper part of which is connected to a rotating shaft, and the lower part of which is connected to a hemispherical float, so that when subjected to waves, the hemispherical float will swing and move radially.

3. The dual-frequency high-efficiency energy harvesting method for a spring pendulum float wave energy power generation device according to claim 2, characterized in that: When the float oscillates, it drives the spring swing arm to oscillate together, which in turn drives the swing hydraulic cylinder and the rear generator to generate electricity. When the float moves radially, it moves along the spring swing arm, which drives the linear hydraulic cylinder and the rear generator to generate electricity.

4. The dual-frequency high-efficiency energy harvesting method for a spring pendulum float wave energy power generation device according to claim 3, characterized in that: When the float is subjected to the horizontal force of the wave at its equilibrium position, the float moves around its axis to drive the oscillating hydraulic cylinder to convert the mechanical energy of the float's oscillation into electrical energy. When the float is subjected to the vertical force of the wave at its equilibrium position, it drives the linear hydraulic cylinder to convert the mechanical energy of the radial motion into electrical energy. After a certain rotation angle is generated, the float will oscillate and move radially under the combined action of the horizontal and vertical forces of the wave, driving the oscillating hydraulic cylinder and the linear hydraulic cylinder to gain energy.

5. The dual-frequency high-efficiency energy harvesting method for a spring pendulum wave energy power generation device according to claim 1, characterized in that: Multiple bolt holes are provided on the swing hydraulic cylinder to fix the swing hydraulic cylinder to the hemispherical float.

6. The dual-frequency high-efficiency energy harvesting method for a spring pendulum wave energy power generation device according to claim 1, characterized in that: The spring pendulum float wave energy generation device can be installed on a platform or crossbeam to achieve integrated installation of the device.

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