Deep sea wind wave combined power generation system based on nonlinear internal resonance principle

Abstract

This invention discloses a deep-sea wind and wave combined power generation system based on the principle of nonlinear internal resonance, belonging to the field of offshore power generation technology. The system includes a semi-submersible base, a wind power generation mechanism, and a wave energy generation device. The semi-submersible base includes three evenly distributed pontoons in a ring shape. The upper and lower ends of adjacent pontoons are fixed by horizontally placed second and third flexible connectors, respectively. The wind power generation mechanism includes a tower located at the center of the three pontoons, and an adjustable tuned mass damper is installed on the tower. A wave energy generation device is installed between the second and third flexible connectors, and the wave energy generation device includes a wave energy float. A water tank is installed inside the wave energy float. The wind causes the tower to vibrate, and energy is transferred to the wave energy float, triggering nonlinear internal resonance. The wave energy float converts the absorbed energy into electrical energy through a wave energy conversion device driven by a heave plate, and dissipates the residual kinetic energy through the water tank.

Description

Technical Field

[0001] This invention belongs to the field of offshore power generation technology, specifically relating to a deep-sea wind and wave combined power generation system based on the principle of nonlinear internal resonance. Background Technology

[0002] With increasing global emphasis on environmental protection and sustainable development, the development and utilization of renewable energy has become a global focus. Traditional fossil fuels are not only finite resources, but their use also generates greenhouse gases and other pollutants that severely damage the environment. To address climate change, reduce environmental pollution, and ensure energy security, countries are increasing investment and research efforts in renewable energy sources such as solar, wind, and hydropower. Among these renewable energy sources, ocean energy has attracted significant attention due to its enormous potential and wide distribution. Especially in deep-sea areas, wind and wave energy resources are abundant and stable, possessing immense development and utilization value.

[0003] Wind and wave energy resources in deep-sea areas are highly complementary, and combining them for joint power generation can significantly improve energy capture efficiency and system stability. A typical wind-wave combined power generation system consists of a floating platform, wind turbines, and wave energy generators. Wind turbines effectively capture wind energy and convert it into electricity, while wave energy generators generate electricity by capturing the kinetic energy of wave motion. This multi-energy complementarity not only fully utilizes ocean energy resources but also enhances the system's resilience and reduces the uncertainty associated with a single energy source. However, traditional wind-wave combined power generation systems are susceptible to vibration in harsh sea conditions, leading to equipment damage or reduced efficiency. Therefore, effective vibration reduction measures are needed to ensure the long-term stable operation of the system. To address this, a deep-sea wind-wave combined power generation system based on the principle of nonlinear internal resonance is proposed. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a deep-sea wind and wave combined power generation system based on the principle of nonlinear internal resonance, thus solving the problems in existing technologies.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] The deep-sea wind and wave combined power generation system based on the principle of nonlinear internal resonance includes a semi-submersible base, on which a wind power generation mechanism and a wave energy generation device are installed.

[0007] The semi-submersible base includes three pontoons evenly distributed in a ring; the wind power generation mechanism includes a tower located at the center of the three pontoons, and an adjustable tuned mass damper is installed on the tower; the lower end of the pontoons is fixed to the lower end of the tower by a first flexible connecting rod placed horizontally; the upper and lower ends of two adjacent pontoons are fixed by a second flexible connecting member and a third flexible connecting member placed horizontally, respectively.

[0008] A wave energy generation device is connected between the second and third flexible connectors via a support column. The wave energy generation device includes a wave energy float, a heave plate, and a wave energy conversion device; a water tank is installed inside the wave energy float.

[0009] The wind-induced vibration of the tower transfers energy to the wave energy buoy, triggering nonlinear internal resonance. The wave energy buoy converts the absorbed energy into electrical energy through the wave energy conversion device driven by the heave plate, and dissipates the residual kinetic energy through the swaying of the water tank fluid.

[0010] Furthermore, the three pontoons are arranged in an equilateral triangle on the sea surface, and the three second flexible connectors are located on the three sides of the equilateral triangle respectively.

[0011] Furthermore, a power conversion nacelle is fixed to the upper end of the tower, and a hub is rotatably connected to the power conversion nacelle. The central axis of the hub is arranged horizontally, and three blades are fixed on the circumferential wall of the hub in a circumferentially evenly distributed manner. The power conversion nacelle is used to convert the mechanical energy generated by the rotation of the blades into electrical energy.

[0012] Furthermore, the adjustable tuned mass damper is installed on the top of the tower via a connector to absorb the vibration energy of the tower caused by wind.

[0013] Furthermore, the water tank is divided vertically into an upper water tank, an intermediate water tank, and a lower water tank.

[0014] Furthermore, the condition for the nonlinear internal resonance is:

[0015] 2ω1=ω2

[0016] Wherein, ω1 is the first-order bending mode frequency of the tower, and ω2 is the heave mode frequency of the float. By adjusting the mass of the adjustable tuned mass damper, the first-order bending mode frequency ω1 of the tower can be obtained, and the heave mode frequency ω2 of the float can be changed by changing the wave energy and the added mass energy of the float through water injection and drainage.

[0017] Furthermore, the formula for calculating the first-order bending mode frequency ω1 of the tower is:

[0018]

[0019] In the formula, EI is the bending stiffness of the tower, and L is the height of the tower (m). 塔筒For the equivalent mass of the tower itself, m TMD The equivalent mass of the adjustable tuned mass damper.

[0020] Furthermore, the first flexible connector, the second flexible connector, and the third flexible connector are all made of carbon fiber reinforced polymer material.

[0021] Furthermore, the tower adopts a tapered steel tube structure.

[0022] The beneficial effects of this invention are:

[0023] 1. Through a nonlinear internal resonance-based directional energy transfer mechanism, the vibration energy of the wind turbine tower is efficiently transferred to the wave energy device, where it is preferentially dissipated by its damping system. Compared with traditional rigid connections or passive damping schemes, this significantly reduces the vibration amplitude at the top of the tower.

[0024] 2. The reduction in vibration amplitude directly reduces the number of alternating stress cycles in the structure, significantly reduces the fatigue damage rate at the connection between the tower and the platform, and extends the overall lifespan of the system.

[0025] 3. Vibration reduction is achieved through the structure's own dynamic characteristics, without relying on active actuators or external power supply devices, thus saving energy costs;

[0026] 4. The hydraulic system of the wave energy device operates in a "dissipation priority, power generation secondary" mode, ensuring the vibration reduction target while almost maintaining the original wave energy power generation efficiency.

[0027] 5. This design method can be extended to other marine renewable energy combinations simply by adjusting the frequency matching ratio and the nonlinear energy transfer path. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the overall structure of the wind and wave combined power generation system of the present invention;

[0030] Figure 2 This is a schematic diagram of the wind and wave combined power generation system of the present invention from another perspective;

[0031] Figure 3 This is a schematic diagram of the float structure of the present invention;

[0032] Figure 4 This is a schematic diagram of the tower structure of the present invention;

[0033] In the diagram: 1-Semi-submersible base, 2-Wave energy buoy, 3-Wind power generation mechanism; 11-Float, 12-First flexible connector, 13-Second flexible connector, 14-Third flexible connector; 21-Water tank, 211-Upper water tank, 212-Middle water tank, 213-Lower water tank; 31-Tower, 32-Power conversion nacelle, 33-Hub, 34-Blade, 311-Connector, 312-Adjustable tuned mass damper. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] like Figure 1 and Figure 2 As shown, the deep-sea wind and wave combined power generation system based on the nonlinear internal resonance principle includes a semi-submersible base 1, on which a wind power generation mechanism 3 and a wave energy generation device are installed to convert wind energy and wave energy into electrical energy respectively.

[0036] The semi-submersible base 1 includes three pontoons 11 evenly distributed in a ring. The upper ends of two adjacent pontoons 11 are fixedly connected by a horizontally placed second flexible connector 13, and the lower ends of two adjacent pontoons 11 are fixedly connected by a horizontally placed third flexible connector 14.

[0037] The three pontoons 11 are arranged in an equilateral triangle on the sea surface, and the three second flexible connectors 13 are located on the three sides of the equilateral triangle respectively. The wind power generation mechanism 3 is located at the center of the three pontoons 11, which can improve the stability of the semi-submersible base 1.

[0038] The wind power generation mechanism 3 includes a tower 31, which is located at the center of three floats 11. The three floats 11 are evenly distributed in a ring around the central axis of the tower 31. A power conversion nacelle 32 is fixed at the upper end of the tower 31. A hub 33 is rotatably connected to the power conversion nacelle 32. The central axis of the hub 33 is horizontally arranged. Three blades 34 are fixed on the peripheral wall of the hub 33 and are evenly distributed in a circumferential direction. The power conversion nacelle 32 is used to convert the mechanical energy generated by the rotation of the blades 34 into electrical energy. The blades 34 are driven to rotate by the wind at sea, and the mechanical energy generated by the rotation of the blades 34 is converted into electrical energy through the power conversion nacelle 32. The power conversion nacelle 32 is connected to an offshore substation.

[0039] In this embodiment, the end of the first flexible connector 12 away from the float 11 is fixed to the tower 31;

[0040] like Figure 4 As shown, an adjustable tuned mass damper 312 is provided inside the tower 31. The adjustable tuned mass damper 32 is installed on the top of the tower 31 by means of a suspension and a connector 311, and is located near the rotation axis of the blade 34, so as to absorb the vibration energy of the tower 31 caused by wind to the maximum extent.

[0041] A wave energy generation device is provided between the second flexible connector 13 and the third flexible connector 14, and is uniformly fixed between the second flexible connector 13 and the third flexible connector 14 by support columns; the wave energy generation device is used to generate electricity by the semi-submersible base 1 floating up and down.

[0042] The first flexible connector 12, the second flexible connector 13 and the third flexible connector 14 flexibly connect the wind power generation mechanism 3 and the wave energy generation device to achieve physical coupling and form a multi-degree-of-freedom vibration system.

[0043] The wave energy power generation device includes a wave energy float 2, a heave plate, and a wave energy conversion device. The wave energy float is a device that floats on the water surface and captures wave energy through the up-and-down movement of the waves. The heave plate is a special type of float that effectively absorbs wave energy through vertical oscillation. The kinetic energy of these devices is converted into electrical energy by the wave energy conversion device (such as a generator).

[0044] like Figure 3 As shown, the wave energy float 2 is equipped with a water tank 21. The water tank 21 is divided into an upper water tank 211, a middle water tank 212 and a lower water tank 213 along the vertical direction. By filling and draining water, the added mass of the wave energy float 2 is changed, thereby changing the float heave mode frequency ω2 of the wave energy float 2.

[0045] In this embodiment, the first flexible connector 12, the second flexible connector 13, and the third flexible connector 14 are all made of composite materials with high elastic modulus but excellent flexibility, such as carbon fiber reinforced polymer, to ensure that they maintain sufficient strength while withstanding large deformations; in this embodiment, the tower 31 adopts a tapered steel pipe structure.

[0046] The mass of the adjustable tuned mass damper 312 should be selected based on the total mass of the tower 31 and the vibration mode to be controlled; the selection process is as follows:

[0047] 1) Simplify the tower 31 into a cantilever beam model with a concentrated mass at the top, and obtain the formula for the first bending mode frequency ω1 of the tower 31;

[0048]

[0049] In the formula, EI is the bending stiffness of the tower, and L is the height of the tower (m). 塔筒For the equivalent mass of the tower itself, m TMD The equivalent mass of the adjustable tuned mass damper 312 is given; by presetting the mass of the adjustable tuned mass damper 312, the natural frequency (first-order bending mode frequency) ω1 of the tower can be obtained.

[0050] 2) By adjusting the mass of the adjustable tuned mass damper 312, the first bending mode frequency ω1 of the tower and the heave mode frequency ω2 of the float are made to satisfy the nonlinear internal resonance condition 2ω1=ω2.

[0051] The wind-induced tower vibration energy is transferred to the wave energy float 2 through the nonlinear coupling term of the flexible hinge, triggering a 2:1 internal resonance; the wave energy float 2 converts the absorbed energy into electrical energy through the large-scale movement of the heave plate to drive the wave energy conversion device, and at the same time dissipates the residual kinetic energy through the fluid sloshing of the water tank 21.

[0052] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0053] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A deep-sea wind and wave combined power generation system based on the principle of nonlinear internal resonance, characterized in that, It includes a semi-submersible base (1), on which a wind power generation mechanism (3) and a wave power generation device are installed; The semi-submersible base (1) includes three pontoons (11) evenly distributed in a ring; the wind power generation mechanism (3) includes a tower (31) located at the center of the three pontoons (11), and an adjustable tuned mass damper (312) is provided on the tower (31); the lower end of the pontoon (11) is fixed to the lower end of the tower (31) by a horizontally placed first flexible connector (12); the upper and lower ends of two adjacent pontoons (11) are fixed by a horizontally placed second flexible connector (13) and a third flexible connector (14), respectively. A wave energy power generation device is connected between the second flexible connector (13) and the third flexible connector (14) via a support column. The wave energy power generation device includes a wave energy float (2), a heave plate, and a wave energy conversion device. A water tank (21) is installed inside the wave energy float (2). The wind-induced tower (31) vibrates, and the energy is transferred to the wave energy float (2), triggering nonlinear internal resonance; the wave energy float (2) converts the absorbed energy into electrical energy through the wave energy conversion device driven by the heave plate, and dissipates the residual kinetic energy through the fluid swaying of the water tank (21); The condition for the nonlinear internal resonance is: 2 = in, The first bending mode frequency of the tower is given. The first-order bending mode frequency of the tower can be obtained by adjusting the mass of the adjustable tuned mass damper (312). By changing the wave energy of the float through water injection and drainage (2), the added mass energy of the float can be used to change the heave mode frequency of the float. ; First-order bending mode frequency of the tower The formula for calculation is: In the formula, EI is the bending stiffness of the tower, and L is the height of the tower. For the tower's own equivalent mass, The equivalent mass of the adjustable tuned mass damper (312).

2. The deep-sea wind and wave combined power generation system based on the nonlinear internal resonance principle according to claim 1, characterized in that, Three pontoons (11) are arranged in an equilateral triangle on the sea surface, and three second flexible connectors (13) are located on the three sides of the equilateral triangle respectively.

3. The deep-sea wind and wave combined power generation system based on the nonlinear internal resonance principle according to claim 1, characterized in that, The upper end of the tower (31) is fixed with a power conversion nacelle (32), and a hub (33) is rotatably connected to the power conversion nacelle (32). The central axis of the hub (33) is arranged horizontally, and three blades (34) are fixed on the circumferential wall of the hub (33). The power conversion nacelle (32) is used to convert the mechanical energy generated by the rotation of the blades (34) into electrical energy.

4. The deep-sea wind and wave combined power generation system based on the nonlinear internal resonance principle according to claim 1, characterized in that, The adjustable tuned mass damper (312) is installed on the top of the tower (31) via a connector (311) to absorb the vibration energy of the tower (31) caused by wind.

5. The deep-sea wind and wave combined power generation system based on the nonlinear internal resonance principle according to claim 1, characterized in that, The water tank (21) is divided vertically into an upper water tank (211), an intermediate water tank (212), and a lower water tank (213).

6. The deep-sea wind and wave combined power generation system based on the nonlinear internal resonance principle according to claim 2, characterized in that, The first flexible connector (12), the second flexible connector (13), and the third flexible connector (14) are all made of carbon fiber reinforced polymer material.

7. The deep-sea wind and wave combined power generation system based on the nonlinear internal resonance principle according to claim 1, characterized in that, The tower (31) adopts a tapered steel pipe structure.

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