Marine photovoltaic system

Abstract

The application discloses a kind of offshore photovoltaic systems in the field of offshore renewable energy technology, including the floating platform connected by multiple floating units, photovoltaic module is equipped on any floating unit, ballast tank is equipped below the floating platform, the end of ballast tank far from floating platform is fixedly connected to seabed by anchor point component, adjusting mechanism is equipped between two adjacent floating units, the adjusting mechanism includes sequentially fixedly connected first connecting piece, memory alloy component and second connecting piece, first connecting piece and second connecting piece are connected with two adjacent floating units respectively, and the phase transition temperature of memory alloy component corresponds to sea surface temperature.The adjusting mechanism of the photovoltaic system can automatically adjust rigidity according to wave frequency, reduce the phenomenon of local stress concentration of floating platform, and better adapt to the changing sea waves of sea surface, improve the ability of the photovoltaic system to resist sea waves.

Description

Technical Field

[0001] This invention relates to the field of marine renewable energy technology, and more particularly to a marine photovoltaic system. Background Technology

[0002] With the rapid development of renewable energy, the available area for onshore photovoltaic (PV) construction is shrinking, and problems such as high construction difficulty, scarcity of land resources, and rapidly increasing costs are becoming increasingly prominent. Therefore, offshore PV systems have been widely researched and applied in recent years.

[0003] Chinese patent application CN120621596A, entitled "A Floating Annular Wave-Resistant Marine Photovoltaic Structure," comprises arc-shaped wave-resistant structural units, spring connectors, photovoltaic buoys, photovoltaic modules, buoy mooring lines, mooring lines, and anchor piles. Several arc-shaped wave-resistant structural units are flexibly connected circumferentially via spring connectors to form a floating annular wave-resistant structure. Inside the annular structure, photovoltaic buoys are laid out in parallel, with photovoltaic modules fixedly installed on the surface of each buoy. This novel floating annular wave-resistant marine photovoltaic structure uses spring connectors to connect the arc-shaped wave-resistant structures into a unified annular shape, providing protection and mooring for the photovoltaic modules within the annular structure. Due to the spring connector, the structure has buffering performance in two directions. However, the complexity and randomness of wind and waves on the actual sea surface are quite large. The impact of waves is not limited to two directions. Stress concentration is very likely to occur at the connection point, i.e., the spring connector. Under such stress concentration for a long time, the connection point will suffer fatigue damage. This not only affects the stability of the platform, but also greatly shortens the service life of the platform. Moreover, the device is a ring structure. Once a connection point fails, the safety of the entire photovoltaic system will be seriously threatened, and it may even lead to the collapse of the photovoltaic system, causing huge economic losses. Summary of the Invention

[0004] To overcome the above-mentioned shortcomings of the prior art, the technical problem to be solved by the present invention is: how to improve the wave resistance of photovoltaic systems.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] The offshore photovoltaic system includes a floating platform composed of multiple floating body units. Each floating body unit is equipped with a photovoltaic module. A ballast tank is located below the floating platform. The end of the ballast tank away from the floating platform is fixedly connected to the seabed by an anchor point assembly. An adjustment mechanism is provided between two adjacent floating body units. The adjustment mechanism includes a first connector, a shape memory alloy assembly, and a second connector that are fixedly connected in sequence. The first connector and the second connector are respectively connected to two adjacent floating body units. The phase change temperature of the shape memory alloy assembly corresponds to the sea surface temperature.

[0007] Furthermore, it also includes a central processing unit located on the floating platform, to which the photovoltaic modules are electrically connected.

[0008] Furthermore, the aforementioned ballast tank includes a water pump electrically connected to the aforementioned central processing unit, the water pump being used to regulate the amount of water stored inside the ballast tank, and the aforementioned float unit is provided with a tilt angle sensor electrically connected to the central processing unit on its ring side.

[0009] Furthermore, a universal bearing is provided between the aforementioned first connector and the shape memory alloy assembly.

[0010] Furthermore, a hydraulic damper is provided between the aforementioned universal bearing and the shape memory alloy assembly, and a wave sensor is provided on the ring side of the aforementioned floating body unit. The aforementioned hydraulic damper and wave sensor are electrically connected to the aforementioned central processing unit.

[0011] Furthermore, the aforementioned floating unit is equipped with a nine-axis attitude sensor that is electrically connected to the aforementioned central processing unit.

[0012] Furthermore, the aforementioned floating unit includes a floating component with compartments filled with foamed polyethylene, and the floating component is made of glass fiber reinforced polyurethane.

[0013] Furthermore, the aforementioned shape memory alloy assembly includes a first mounting component, a shape memory alloy component, and a second mounting component that are fixedly arranged in sequence. The shape memory alloy component includes multiple interwoven titanium-nickel shape memory alloy wires, with both ends of any of the aforementioned titanium-nickel shape memory alloy wires being fixedly connected to the first mounting component and the second mounting component, respectively.

[0014] Furthermore, the aforementioned anchor point assembly includes a connecting plate that is connected to the bottom of the ballast tank via multiple connecting chains. The connecting plate is connected to multiple anchor chains that are laid out along its circumference, and an anchor is connected to the end of the anchor chain away from the connecting plate.

[0015] The beneficial effects of this invention are as follows: The photovoltaic system splices multiple floating units into a floating platform through multiple adjustment mechanisms, and is equipped with photovoltaic modules, ballast tanks and anchor point components. The adjustment mechanism includes a first connector, a shape memory alloy component and a second connector that are fixedly connected in sequence. The phase change temperature of the shape memory alloy component corresponds to the sea surface temperature. By utilizing the characteristic that the shape memory alloy can change its state with temperature, the adjustment mechanism can automatically adjust its stiffness according to the wave frequency, reduce the phenomenon of local stress concentration on the floating platform, and thus better adapt to the changing sea waves, thereby improving the photovoltaic system's ability to resist sea waves. Attached Figure Description

[0016] Figure 1 This is a structural view of the marine photovoltaic system of the present invention;

[0017] Figure 2 This is a structural view of the regulating mechanism in the marine photovoltaic system of the present invention;

[0018] Figure 3 This is a structural view of the floating body unit in the marine photovoltaic system of the present invention;

[0019] Figure 4 This is a system block diagram of the marine photovoltaic system of the present invention.

[0020] The components in the diagram are labeled as follows: 1-Photovoltaic module, 2-Adjustment mechanism, 3-Ballast tank, 4-Anchor, 5-Anchor chain, 6-Floating body unit, 7-First connector, 8-Second connector, 9-Shape memory alloy component, 10-Central processing unit, 11-Tilt angle sensor, 12-Universal bearing, 13-Hydraulic damper, 14-Wave sensor, 15-Nine-axis attitude sensor, 16-Floating body component, 17-Compartment, 18-Foamed polyethylene, 19-First mounting component, 20-Shape memory alloy component, 21-Second mounting component, 22-Connecting disc, 23-Connecting chain, 24-Anchor point assembly. Detailed Implementation

[0021] The invention will be further described below with reference to the accompanying drawings.

[0022] like Figures 1-4As shown, the offshore photovoltaic system includes a floating platform composed of multiple floating units 6 connected together. Each floating unit 6 is equipped with a photovoltaic module 1. A ballast tank 3 is located below the floating platform. The end of the ballast tank 3 furthest from the floating platform is fixedly connected to the seabed via an anchoring assembly 24. An adjustment mechanism 2 is provided between two adjacent floating units 6. The adjustment mechanism 2 includes a first connector 7, a shape memory alloy assembly 9, and a second connector 8, which are sequentially fixedly connected. The first connector 7 and the second connector 8 are respectively connected to two adjacent floating units 6. The phase change temperature of the shape memory alloy assembly 9 corresponds to the sea surface temperature. The temperature of seawater varies depending on geographical location, latitude, ocean currents, and seasonal changes. In winter, the surface seawater temperature typically ranges from -1.5℃ to 26℃, while in summer it ranges from 25℃ to 36.8℃. In this embodiment, the offshore photovoltaic system is located along the northern coast of the Yellow Sea. The surface water temperature along the northern coast of the Yellow Sea in winter is between 1-2℃, 2-3℃ in the central region, and 4-5℃ in the southern region, generally close to or below 5℃. Therefore, the phase change temperature of the shape memory alloy component 9 is set to 5℃. It is worth noting that personnel need to replace the adjustment mechanism 2 according to the region and season of the photovoltaic system, i.e., replace it with a shape memory alloy component 9 that has a phase change temperature adapted to the sea surface temperature. The photovoltaic component 1 is an existing structure, which can be consistent with the structure of the photovoltaic component 1 in the floating annular anti-wave marine photovoltaic structure in the Chinese patent application in the background art. For example, it includes a support frame, solar panels, a controller, and an inverter. Preferably, multiple electric cylinders are provided between the support frame and the solar panels. The electric cylinders can be used to adjust the tilt angle of the solar panels to facilitate the reception of sunlight. The preferred floating unit 6 is a regular prism, whose base can be a regular square or a regular hexagon. The base is preferably a regular hexagon with a side length of 10m, and the height of the prism is 1.5m. The float unit 6 has a first plug-in on its ring side, and the first plug-in has a first plug-in hole through it. The first connector 7 and the second connector have a second plug-in on the side near the float unit 6. The second plug-in has a second plug-in hole opposite to the first plug-in hole of the first plug-in connected to it. The first plug-in and the second plug-in can be plugged in and engaged.

[0023] During assembly, the floating body units 6 are first manufactured, and then adjacent floating body units 6 are connected. The first connector is inserted into the corresponding second connector, and after insertion, bolts and nuts are used for fixing. The bolt preload is preferably controlled within 50KN to ensure the reliability and flexibility of the connection. After the multiple floating body units 6 are assembled, the floating platform is initially installed. Subsequently, multiple photovoltaic modules 1, ballast tanks 3, and anchor point components 24 are installed accordingly. After installation, it is placed at sea and fixed with anchor point components 24, and the marine photovoltaic system begins to work. When the seawater temperature is below or close to 5℃, the shape memory alloy component 9 is in a low-temperature soft state, in the martensitic phase, and has superelasticity, allowing the hinge to undergo large recoverable deformation under stress, macroscopically exhibiting low stiffness and high flexibility. At this time, the adjustment mechanism 2 can swing freely like the stem of seaweed (it is more free and flexible than the traditional fixed direction). Through a wide range of reciprocating motion, it converts the kinetic energy of the waves into the elastic potential energy of the material and dissipates it, thereby consuming the energy of the waves to a certain extent and playing a good role in wave resistance. The wave energy consumed can effectively reduce the impact damage of the waves on the adjustment mechanism 2 and extend its service life. When high-frequency waves (usually accompanied by impact loads) strike, the internal friction heat generated by the periodic deformation of the shape memory alloy component 9 will cause its temperature to rise instantaneously. Once the temperature exceeds its phase transformation temperature (such as 5°C set in this embodiment), the alloy will transform from the martensitic phase to the austenitic phase. The austenitic phase has extremely high strength and stiffness. Macroscopically, the overall rigidity of the flexible adjustment mechanism 2 is significantly enhanced, thereby locking the connection structure between the floating body units 6 and providing strong impact resistance.

[0024] This offshore photovoltaic system connects multiple floating units 6 via adjustment mechanisms 2, each equipped with shape memory alloy components 9. Damage to a single floating unit 6 will not cause the entire photovoltaic system to collapse and cease operation. Furthermore, the shape memory alloy components 9 utilize their phase transition temperature to achieve two different states, allowing the adjustment mechanisms 2 to automatically adjust stiffness according to wave frequency. In the soft state, they efficiently dissipate energy; in the hard state, they enhance the structure's impact resistance. This further optimizes the load response strategy under different wave conditions, improving the photovoltaic system's wave resistance in complex sea conditions, reducing stress concentration, and lowering the probability of damage. Simulation analysis shows that compared to traditional rigid platforms, the adjustment mechanism 2 of this invention can reduce peak wave loads by 35%. This means that under the same extreme sea conditions, the wave impact force on this photovoltaic system is significantly reduced, greatly improving the structural safety and stability. It can operate stably under harsh conditions with wave heights greater than 10 meters, while the maximum wave resistance of traditional rigid platforms is typically only for wave heights of 6 meters or less.

[0025] The system also includes a central processing unit 10 mounted on a floating platform, to which the aforementioned photovoltaic module 1 is electrically connected. The central processing unit 10 is the core of the computer system's computation and control; it is a very large-scale integrated circuit responsible for interpreting computer instructions, processing software data, and executing various computational tasks. The photovoltaic module is electrically connected to the central processing unit 10; that is, the solar panel, controller, inverter, and multiple electric cylinders positioned between the support frame and the solar panel are all electrically connected to the central processing unit 10. In this design, the central processing unit 10 can collect relevant information about the photovoltaic module 1 at any time. If the photovoltaic module 1 is damaged, it can be quickly repaired. Furthermore, the central processing unit 10 can control the lifting and lowering of multiple electric cylinders to change the tilt angle of the solar panel, thereby facilitating solar energy absorption.

[0026] The aforementioned ballast tank 3 includes a water pump electrically connected to the aforementioned central processing unit 10. This water pump is used to regulate the water volume inside the ballast tank 3. The aforementioned buoyancy unit 6 has a tilt angle sensor 11 electrically connected to the central processing unit 10 on its ring side. The tilt angle sensor 11 (also known as an inclinometer or tilt sensor) is an electronic device used to measure the tilt angle of an object relative to a horizontal plane (or the direction of gravity) and convert the change in tilt angle into an electrical signal (such as voltage, current, digital signal, etc.) for output. The tilt angle sensor 11 can be a vibration-type tilt sensor. The ballast tank 3 includes a sealed shell, with a ballast water tank at the bottom of the sealed shell. The ballast water tank is connected to an electric pump, which is connected to a water supply pipe. The sealed shell has a water inlet, and the inlet of the water supply pipe is connected to the water inlet. A valve is located near the inlet end of the water supply pipe. Both the valve and the electric pump are electrically connected to the central processing unit 10. Before entering the seawater, the photoelectric system first injects seawater or heavy materials (such as steel shot) into the ballast water tank through the water supply pipe, ensuring that the system's center of gravity is more than 30% lower than its center of buoyancy. The central processing unit 10 receives the tilt angle of the floating body unit 6 via the tilt angle sensor 11. The central processing unit 10 integrates this tilt angle information to obtain the tilt angle of the floating platform. When the tilt angle of the floating platform is greater than 20 degrees, the central processing unit 10 controls the electric pump of the ballast tank 3 to pump in additional pressurized water, generating a restoring torque that can correct the tilt angle to below 3 degrees within 5 seconds. This design reduces reliance on complex anchor point components 24 such as multiple anchor chains 5, lowers the construction cost of the anchor point components 24, and improves the adaptability of the photovoltaic system under different sea states and seabed conditions, thus enhancing the economy and practicality of the offshore photovoltaic system to a certain extent.

[0027] A universal bearing 12 is provided between the first connecting member 7 and the shape memory alloy assembly 9. The universal bearing 12 is a mechanical structure that uses a spherical connection to achieve power transmission between different axes. The installation of the universal bearing 12 can increase the flexibility between the floating body units 6 to a certain extent.

[0028] A hydraulic damper 13 is provided between the universal bearing 12 and the shape memory alloy component 9. A wave sensor 14 is provided on the ring side of the floating body unit 6. The hydraulic damper 13 and the wave sensor 14 are electrically connected to the central processing unit 10. The central processing unit 10 collects wave frequency information transmitted from the wave sensor 14 in real time. When the wave frequency is low and below the first preset value, the central processing unit 10 issues a command to put the damper in a soft state. At this time, the relative movement between the floating body units 6 is more flexible, which can better absorb wave energy, just like seaweed swaying and consuming energy naturally in seawater. When the wave frequency is high and above the second preset value, it indicates that a large impact may occur. The central processing unit 10 controls the damper to switch to a hard state to enhance the rigidity of the structure and resist the impact of the waves.

[0029] The aforementioned floating body unit 6 is equipped with a nine-axis attitude sensor 15 on its ring side, which is electrically connected to the aforementioned central processing unit 10. The nine-axis attitude sensor 15 is a high-performance three-dimensional motion attitude measurement system based on MEMS technology. It consists of a three-axis accelerometer, a three-axis gyroscope, and a three-axis magnetometer (or electronic compass). Through an embedded low-power ARM processor and special data fusion technology, it outputs high-precision three-dimensional attitude and orientation data in real time. This design allows the central processing unit 10 to better understand the attitude of the floating body unit 6.

[0030] The aforementioned floating unit 6 includes a floating component 16 with a compartment 17 filled with foamed polyethylene 18. The floating component 16 is made of glass fiber reinforced polyurethane. The density of the glass fiber reinforced polyurethane material is less than or equal to 0.6 g / cm³, exhibiting good buoyancy performance. Simultaneously, its tensile strength is greater than or equal to 80 MPa, ensuring the structural strength of the floating body under complex sea conditions. The compartment 17 inside the floating component 16 enhances its structural stability, while the foamed polyethylene 18 further improves its buoyancy and impact resistance.

[0031] The aforementioned shape memory alloy component 9 includes a first mounting member 19, a shape memory alloy component 20, and a second mounting member 21, which are sequentially fixedly arranged. The shape memory alloy component 20 includes multiple interwoven titanium-nickel shape memory alloy wires, with both ends of any of the aforementioned titanium-nickel shape memory alloy wires fixedly connected to the first mounting member 19 and the second mounting member 21, respectively. Titanium-nickel shape memory alloy wire is a shape memory alloy composed of nickel and titanium, possessing a unique shape memory effect, superelasticity, and corrosion resistance. Weaving it together and placing it between the first mounting member 19 and the second mounting member 21 provides it with excellent ductility and toughness, reducing the risk of damage after its rigidity is increased.

[0032] The aforementioned anchor assembly 24 includes a connecting plate 22 connected to the bottom of the ballast tank 3 via multiple connecting chains 23. The connecting plate 22 is connected to multiple anchor chains 5 arranged circumferentially thereon, with an anchor 4 connected to the end of each anchor chain 5 furthest from the connecting plate 22. The connection plate 22 can increase the number of anchor chains 5 to a certain extent, improving the stability of the photovoltaic system and preventing waves from blowing it away from the installation area.

[0033] In summary, this application proposes a marine photovoltaic system. Compared to traditional rigid platforms that rely on material strength to rigidly resist wind and waves, or those using elastic connections in a single direction, both of these methods are prone to stress concentration at connection points due to the often complex sea conditions, making the floating platform susceptible to damage from wave impacts. The adjustment mechanism 2 of this invention allows for deflection in any direction between the floating body units 6, effectively dispersing wave loads and resulting in better resistance to wind and waves for the photovoltaic system, thus extending the overall lifespan of the floating platform.

Claims

1. A marine photovoltaic system, comprising a floating platform composed of multiple floating units (6) connected together, wherein each floating unit (6) is equipped with a photovoltaic module (1), and a ballast tank (3) is provided below the floating platform, wherein the end of the ballast tank (3) away from the floating platform is fixedly connected to the seabed by an anchor point assembly (24), characterized in that: An adjustment mechanism (2) is provided between two adjacent floating bodies (6). The adjustment mechanism (2) includes a first connector (7), a shape memory alloy component (9), and a second connector (8) that are fixedly connected in sequence. The first connector (7) and the second connector (8) are respectively connected to two adjacent floating bodies (6). The phase change temperature of the shape memory alloy component (9) corresponds to the sea surface temperature.

2. The offshore photovoltaic system as described in claim 1, characterized in that: It also includes a central processing unit (10) located on the floating platform, and the photovoltaic module (1) is electrically connected to the central processing unit (10).

3. The offshore photovoltaic system as described in claim 2, characterized in that: The ballast tank (3) includes a water pump electrically connected to the central processing unit (10), the water pump being used to adjust the amount of water stored inside the ballast tank (3), and the float unit (6) is provided with a tilt angle sensor (11) electrically connected to the central processing unit (10) on its circumferential side.

4. The offshore photovoltaic system as described in claim 2, characterized in that: A universal bearing (12) is provided between the first connector (7) and the shape memory alloy assembly (9).

5. The offshore photovoltaic system as described in claim 4, characterized in that: A hydraulic damper (13) is provided between the universal bearing (12) and the shape memory alloy assembly (9), and a wave sensor (14) is provided on the circumferential side of the floating body unit (6). The hydraulic damper (13) and the wave sensor (14) are both electrically connected to the central processing unit (10).

6. The marine photovoltaic system as described in claim 2, characterized in that: The floating body unit (6) is provided with a nine-axis attitude sensor (15) on its ring side, which is electrically connected to the central processing unit (10).

7. The offshore photovoltaic system as described in claim 1, characterized in that: The float unit (6) includes a float component (16) having a compartment (17) filled with foamed polyethylene (18), and the float component (16) being made of glass fiber reinforced polyurethane.

8. The offshore photovoltaic system as described in any one of claims 1-7, characterized in that: The memory alloy component (9) includes a first mounting component (19), a memory alloy component (20), and a second mounting component (21) that are fixedly arranged in sequence. The memory alloy component (20) includes multiple interwoven titanium-nickel memory alloy wires, and the two ends of any of the titanium-nickel memory alloy wires are fixedly connected to the first mounting component (19) and the second mounting component (21) respectively.

9. The offshore photovoltaic system as described in claim 8, characterized in that: The anchor point assembly (24) includes a connecting plate (22) connected to the bottom of the ballast tank (3) via multiple connecting chains (23). The connecting plate (22) is connected to multiple anchor chains (5) arranged along its circumference. An anchor (4) is connected to one end of the anchor chain (5) away from the connecting plate (22).

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