Offshore gravity energy storage system

Abstract

The invention discloses an offshore gravity energy storage system which comprises a mounting platform and heavy objects pulled by cables, the heavy objects can move up and down in seawater relative to the mounting platform, the multiple heavy objects are arranged in the circumferential direction of the mounting platform, and the number of the heavy objects is a multiple of an even number. The two weights oppositely arranged in the radial direction of the mounting platform form a working group, at least two reel power generation mechanisms are arranged on the mounting platform, and the multiple reel power generation mechanisms are arranged in a layered mode in the vertical direction; the reel power generation mechanism comprises a rotating disc rotationally arranged on the mounting platform, a support fixedly arranged on the rotating disc and a winding roll rotationally arranged on the support. According to the invention, through the vertically layered reel power generation mechanism and the circumferentially arranged weights, the power generation and energy storage process can be continuously carried out, the energy storage efficiency is greatly improved, and after all the weights are put down to the seabed, the mounting platform can be anchored to resist extreme weather such as typhoon and the like.

Description

Technical Field

[0001] This invention relates to the field of marine gravity energy storage technology, and more specifically, to a marine gravity energy storage system. Background Technology

[0002] Offshore gravity energy storage is a cutting-edge technology that applies the principles of gravity energy storage to the marine environment. It primarily aims to address the intermittency and volatility of offshore renewable energy sources (such as offshore wind power) by improving the stability and energy efficiency of power systems through energy storage. Current technologies typically use a single heavy object for gravity energy storage, resulting in relatively low storage efficiency and total storage capacity. Furthermore, the system exhibits poor stability during extreme weather events such as typhoons. Summary of the Invention

[0003] This invention overcomes the shortcomings of existing technologies and proposes a marine gravity energy storage system with a reasonable structural design. Through the vertically layered design of the reel power generation mechanism and the circumferentially arranged weights, the power generation and energy storage processes can be carried out continuously, greatly improving energy storage efficiency and total energy storage capacity. After all the weights are lowered to the seabed, the installation platform can be anchored to resist extreme weather such as typhoons.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A marine gravity energy storage system includes an installation platform and weights traction by cables. The weights are movable up and down relative to the platform in seawater. Multiple weights are arranged circumferentially along the platform, with the number of weights being an even multiple. Two weights arranged radially opposite each other on the platform form a working group. A reel-type power generation mechanism is installed on the platform. This mechanism includes a turntable rotatably mounted on the platform, a bracket fixedly mounted on the turntable, a reel rotatably mounted on the bracket, a drive motor located on one side of the reel and capable of rotating it, and a generator located on the other side of the reel and driven by its rotation to generate electricity. The cable includes components capable of being wound around the upper half of the reel. The system includes an upper cable, a lower cable that can be wound around the lower half of the reel, and a heavy cable connected to a heavy object. The upper and lower cables are both fixed at the bottom of the reel at the beginning. When one of the upper or lower cables is unwound from the reel, the other is wound back onto the reel. The ends of the upper and lower cables away from the reel are provided with connecting parts, and the ends of the heavy cable away from the heavy object are provided with quick-release heads. The quick-release heads are detachably connected to the connecting parts. The mounting platform is equipped with an initial limit device for the heavy object near the reel and an end limit device for the heavy object away from the reel. Both the initial and end limit devices can limit the quick-release heads.

[0006] By adopting the above technical solution, the installation platform can be circular. Considering the varying depths of the seabed, the shape of the platform can be adjusted according to the specific seabed depth, such as elliptical, irregular circular, or polygonal. The cable reel is roughly positioned at the center of the platform, and the cable length is determined based on the depth of the seabed, with the length of the cable reaching the bottom at the deepest point as the design standard. During descent, the cable reel rotates, generating electricity through a generator. Pulling the cable up is achieved by a drive motor rotating the reel to wind the cable. Multiple weights, in even-numbered increments, are placed on the platform, with two weights positioned opposite each other forming a working group. After descent or pull-up of two weights in one working group, the turntable is rotated, and the quick-release head is connected to the connector to continue descent or pull-up of two weights in another working group. This allows for the completion of all weight descent and power generation during peak electricity hours, followed by pulling up of all weights during off-peak hours or when the platform needs to absorb excess power from other renewable energy sources. Taking the sinking of a heavy object as an example, during the sinking of one heavy object in a working group, after the upper cable's connector is connected to the quick-release head of the heavy object cable, the lower cable in the same working group winds onto the lower half of the reel as the heavy object sinks. Specifically, both the upper and lower cables are welded and fixed to the bottom of the reel at the starting end. The initial limiting device for the heavy object restricts its movement before sinking and after being pulled up, while the final limiting device restricts its movement after it sinks to the seabed. This is achieved by limiting the quick-release head at the end near the reel. This design significantly improves the efficiency of offshore heavy object energy storage and power generation.

[0007] Preferably, transmission gears are provided on both sides of the winding reel, the drive motor is connected to a motor coupling, the motor coupling is connected to a motor gear, and the motor gear can be directly or indirectly meshed with the transmission gear on one side of the winding reel. The generator is connected to a generator coupling, the generator coupling is connected to a generator gear, and the generator gear can be directly or indirectly meshed with the transmission gear on the other side of the winding reel.

[0008] By adopting the above technical solution, during the process of lowering a heavy object to generate electricity, the generator coupling is connected to the generator, while the motor coupling is disconnected from the drive motor, thus achieving torque transmission only at the generator end; similarly, during the process of pulling a heavy object to store energy, the generator coupling is disconnected from the generator, while the motor coupling is connected to the drive motor, thus achieving torque transmission only at the drive motor end.

[0009] Preferably, the connecting part is inserted into the quick-release head to achieve a detachable connection with the quick-release head, or the connecting part is screwed into the quick-release head to achieve a detachable connection with the quick-release head.

[0010] By adopting the above technical solution, the connecting part and the quick-release head can be detachably fixed by means of direct insertion or threaded connection, making connection and disassembly quick and convenient.

[0011] Preferably, both the initial weight limiting device and the final weight limiting device include a limiting seat, an insertion port on the limiting seat, a passage on the limiting seat that allows the quick-release head to pass through, and a plug that can be inserted into the insertion port and reduces the passage area of ​​the passage. The plug has a limiting port that can be positioned opposite to the passage.

[0012] By adopting the above technical solution, when the insert is not inserted, both the quick-release head and the connecting part can pass through the through port, while when the insert is inserted, the quick-release head is blocked and limited by the limiting port.

[0013] Preferably, at least one set of cable support devices is provided on the installation platform between the initial limit device and the final limit device of the heavy object. Each set of cable support devices includes two cable support units. Each cable support unit includes a movable support base, a lifting cylinder on the support base, a guide slide at the end of the lifting cylinder that can guide the cable, and a position sensor on the support base.

[0014] By adopting the above technical solution, each cable support unit can provide auxiliary support for the cable and the weight. The purpose of setting two cable support units is to prevent the connector and / or quick-release head from colliding and interfering with the guide slide, thus affecting the normal guidance of the cable. The position sensor can detect the position of the connector or quick-release head. When the connector and / or quick-release head is about to pass, one of the lifting cylinders is controlled to descend and the other lifting cylinder is controlled to rise. When the connector or quick-release head is between the two lifting cylinders, the descending lifting cylinder is controlled to rise and the rising lifting cylinder is controlled to descend, so that the connector or quick-release head can pass through the guide slide without contacting it. After the connector or quick-release head has passed smoothly, the two lifting cylinders are controlled to be at approximately the same height to guide the cable smoothly.

[0015] Preferably, the installation platform is provided with a cable pulling device, which includes a movable pulling base, a pulling cylinder provided on the pulling base and capable of being raised and lowered, and a pulling head provided at the end of the pulling cylinder. The pulling head is provided with a receiving groove for accommodating the cable, and the pulling head can abut against the connecting part and drive the connecting part to move.

[0016] By adopting the above technical solution, after one of the heavy objects in the working group is pulled up, the upper or lower half of the cable on the other side of the reel will be unwound. At this time, by placing the cable at the connection part in the receiving groove, and by using the traction base to drive the connection part and the cable to move closer to the end limit device of the heavy object, the upper or lower half of the cable can be connected to the cable of the heavy object at this location.

[0017] Preferably, at least two reel-type power generation mechanisms are provided, and multiple reel-type power generation mechanisms are arranged in layers in the vertical direction so that the power generation or energy storage process can be carried out continuously.

[0018] By adopting the above technical solution, taking two reel power generation mechanisms arranged vertically as an example, by setting up two reel power generation mechanisms, cable tangling can be avoided. When the turntable corresponding to the upper or lower reel power generation mechanism rotates, and the quick-release head and connecting part are disassembled or assembled, or when the quick-release head is limited by the plug block, the reel of the other reel power generation mechanism can be wound or unwound simultaneously. This avoids the time wasted when one reel power generation mechanism is rotating or stopped, and allows the process of heavy objects sinking to generate electricity and pulling up to store energy to be carried out continuously, thus improving efficiency.

[0019] Preferably, the turntable is provided with a pulley frame, and pulleys are rotatably mounted on the pulley frame, with the upper and lower half cables passing through the lower surface of the pulleys.

[0020] By adopting the above technical solution, the upper and lower half cables are fixed at the bottom of the winding reel at the starting end. The upper and lower half cables are wound or unwound from the bottom of the winding reel, which serves as a guide for the upper and lower half cables.

[0021] Preferably, the initial and final positions of the weight are both located in the seawater, and the final position of the weight is located on the seabed.

[0022] By adopting the above technical solution, the buoyancy changes when the heavy objects enter and leave the water are avoided, so that the power generation process is not affected by fluctuations and the power generation is more stable. After all the heavy objects are lowered to the seabed, the installation platform can be anchored to resist extreme weather such as typhoons. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a specific embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram illustrating the structure of the reel-type power generation mechanism according to a specific embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram illustrating the connection structure of the quick-release head and the connecting part according to a specific embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram illustrating the structure of the final limiting device for heavy objects according to a specific embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram illustrating the structure of the cable support device according to a specific embodiment of the present invention;

[0028] Figure 6 This is a schematic diagram illustrating the initial state of a heavy object sinking to generate electricity when there are two reel power generation mechanisms, according to a specific embodiment of the present invention.

[0029] Figure 7 This is a schematic diagram illustrating the initial state of energy storage by pulling up a heavy object when there are two reel power generation mechanisms, according to a specific embodiment of the present invention.

[0030] Figure 8 This is a schematic diagram illustrating the state of the cable traction device during traction in a specific embodiment of the present invention;

[0031] Figure 9 This is a schematic diagram illustrating the structure of two reel-type power generation mechanisms in a specific embodiment of the present invention;

[0032] Figure 10 This is a schematic diagram illustrating the structure of the cable pulling device according to a specific embodiment of the present invention;

[0033] Figure 11 This is a schematic diagram illustrating the initial position of the weight in a specific embodiment of the present invention.

[0034] In the diagram: 1. Installation platform; 2. Cable; 21. Upper cable; 22. Lower cable; 23. Heavy cable; 24. Connecting part; 25. Quick-release head; 3. Heavy object; 4. Reel generator mechanism; 41. Turntable; 411. Pulley frame; 412. Pulley; 42. Bracket; 43. Reel; 44. Drive motor; 45. Generator; 46. Transmission gear; 47. Motor coupling; 48. Motor gear; 49. Generator coupling; 50. 5. Initial limit device for heavy objects; 6. Final limit device for heavy objects; 61. Limit seat; 62. Insertion port; 63. Pass-through port; 64. Insert block; 65. Limit port; 7. Cable support device; 71. Cable support unit; 72. Support base; 73. Lifting cylinder; 74. Guide slide; 75. Position sensor; 8. Cable traction device; 81. Traction base; 82. Traction cylinder; 83. Traction head; 84. Receiving slot. Detailed Implementation

[0035] The technical solutions in this embodiment 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.

[0036] It should be noted that in the description of this invention, all directional indications (such as up, down, forward, backward, etc.) are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0037] Furthermore, in this invention, the use of terms such as "first," "second," etc., is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. In the description of this invention, "a number" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0039] like Figure 1-11As shown, a marine gravity energy storage system includes an installation platform 1 and a weight 3 pulled by a cable 2. The weight 3 can move up and down in seawater relative to the installation platform 1. Multiple weights 3 are arranged around the circumference of the installation platform 1, and the number of weights 3 is a multiple of an even number. Two weights 3 arranged radially opposite each other on the installation platform 1 form a working group. A reel power generation mechanism 4 is installed on the installation platform 1. The reel power generation mechanism 4 includes a turntable 41 rotatably mounted on the installation platform 1, a bracket 42 fixedly mounted on the turntable 41, a reel 43 rotatably mounted on the bracket 42, a drive motor 44 located on one side of the reel 43 and capable of driving the reel 43 to rotate, and a generator 45 located on the other side of the reel 43 and driven by the rotation of the reel 43 to generate electricity. The cable 2 includes an upper cable 2 that can be wound around the upper half of the reel 43. 1. The lower half cable 22, which can be wound around the lower half of the winding reel 43, and the heavy object cable 23 connected to the heavy object 3, are both fixed at the bottom of the winding reel 43 at the starting end of the upper half cable 21 and the lower half cable 22. When one of the upper half cable 21 and the lower half cable 22 is unwound by the winding reel 43, the other half will be wound into the winding reel 43. The upper half cable 21 and the lower half cable 22 are provided with a connecting part 24 at the end away from the winding reel 43. The heavy object cable 23 is provided with a quick-release head 25 at the end away from the heavy object 3. The quick-release head 25 is detachably connected to the connecting part 24. The mounting platform 1 is provided with a heavy object initial limit device 5 near the winding reel 43 and a heavy object final limit device 6 away from the winding reel 43. Both the heavy object initial limit device 5 and the heavy object final limit device 6 can limit the quick-release head 25.

[0040] By adopting the above technical solution, the installation platform 1 can be circular. Considering the varying depths of the seabed, the shape of the installation platform 1 can be adjusted according to the specific seabed depth, such as elliptical, irregular circular, or polygonal. The cable reel 43 is approximately positioned at the center of the installation platform 1, and the length of the cable 2 is also set according to the different seabed depths, with the length of the weight 3 touching the bottom at the deepest point as the design standard. During the sinking process of the weight 3, the cable reel 43 is rotated, which in turn generates electricity through the generator 45. The upward pulling of the weight 3 is achieved by the drive motor 44 rotating the cable reel 43 to wind the cable 2. By setting multiple weights 3 in even-numbered increments, and with two weights 3 positioned opposite each other on the installation platform 1 forming a working group, after completing the sinking or pulling action of two weights 3 in one working group, the turntable 41 is rotated, and the quick-release head 25 is connected to the connecting part 24 to continue the sinking or lifting action of two weights 3 in another working group. The system can generate electricity by sinking all the heavy objects 3 during peak power periods, and then pull them up during off-peak periods or when it needs to absorb the power curtailed from other renewable energy sources. Taking the sinking of heavy object 3 as an example, in one working group, during the sinking of one heavy object 3, the connecting part 24 of the upper cable 21 is connected to the quick-release head 25 of the heavy object cable 23. As the heavy object 3 sinks, the lower cable 22 in the same working group is wound around the lower half of the reel 43. Specifically, the upper cable 21 and the lower cable 22 are both welded and fixed to the bottom of the reel 43 at the starting end. The initial limiting device 5 limits the heavy object 3 before sinking and after being pulled up, while the final limiting device 6 limits the heavy object 3 after it sinks to the seabed. Specifically, the quick-release head 25 is used to limit and fix the heavy object 3 near the reel 43. This setup significantly improves the efficiency of energy storage and power generation for heavy marine vessels.

[0041] The winding reel 43 has transmission gears 46 on both sides. The drive motor 44 is connected to a motor coupling 47, which in turn is connected to a motor gear 48. The motor gear 48 can directly or indirectly mesh with the transmission gear 46 on one side of the winding reel 43. The generator 45 is connected to a generator coupling 49, which is connected to a generator gear 50. The generator gear 50 can directly or indirectly mesh with the transmission gear 46 on the other side of the winding reel 43. During the process of lowering the heavy object 3 to generate electricity, the generator coupling 49 is connected to the generator 45, while the motor coupling 47 is disconnected from the drive motor 44, thus achieving torque transmission only at the generator 45 end. Similarly, during the process of pulling the heavy object 3 up to store energy, the generator coupling 49 is disconnected from the generator 45, while the motor coupling 47 is connected to the drive motor 44, thus achieving torque transmission only at the drive motor 44 end.

[0042] The connecting part 24 is inserted into the quick-release head 25 to achieve a detachable connection with the quick-release head 25, or the connecting part 24 is screwed into the quick-release head 25 to achieve a detachable connection with the quick-release head 25. The connecting part 24 and the quick-release head 25 can be detachably and securely connected by a straight insertion or a threaded connection, making connection and disassembly quick and convenient.

[0043] Furthermore, both the initial weight limiting device 5 and the final weight limiting device 6 include a limiting seat 61, an insertion port 62 provided on the limiting seat 61, a passage port 63 provided on the limiting seat 61 that allows the quick-release head 25 to pass through, and a plug 64 that can be inserted into the insertion port 62 and reduces the passage area of ​​the passage port 63. The plug 64 is provided with a limiting port 65 that can be arranged opposite to the passage port 63. When the plug 64 is not inserted, both the quick-release head 25 and the connecting part 24 can pass through the passage port 63, while when the plug 64 is inserted, the quick-release head 25 is blocked and limited by the limiting port 65.

[0044] Furthermore, at least one set of cable support devices 7 is provided on the installation platform 1 between the initial limit device 5 and the final limit device 6 of the heavy object. Each set of cable support devices 7 includes two cable support units 71. Each cable support unit 71 includes a movable support base 72, a lifting cylinder 73 on the support base 72, a guide slide 74 at the end of the lifting cylinder 73 that can guide the cable 2, and a position sensor 75 on the support base 72. Each cable support unit 71 can provide auxiliary support for the cable 2 and the weight 3. The purpose of setting two cable support units 71 is to prevent the connecting part 24 and / or quick-release head 25 from colliding and interfering with the guide slide 74, thus affecting the normal guidance of the cable 2. The position sensor 75 can detect the position of the connecting part 24 or quick-release head 25. When the connecting part 24 and / or quick-release head 25 is about to pass, one of the lifting cylinders 73 is controlled to descend and the other lifting cylinder 73 is controlled to rise. When the connecting part 24 or quick-release head 25 is between the two lifting cylinders 73, the descending lifting cylinder 73 is controlled to rise and the rising lifting cylinder 73 is controlled to descend, so that the connecting part 24 or quick-release head 25 can pass through the guide slide 74 without contacting it. After the connecting part 24 or quick-release head 25 has passed smoothly, the two lifting cylinders 73 are controlled to be at approximately the same height to guide the cable 2 smoothly.

[0045] Additionally, a cable traction device 8 is provided on the installation platform 1. The cable traction device 8 includes a movably mounted traction base 81, a traction cylinder 82 mounted on the traction base 81 and capable of being raised and lowered, and a traction head 83 located at the end of the traction cylinder 82. The traction head 83 is provided with a receiving groove 84 for accommodating the cable 2. The traction head 83 can abut against the connecting part 24 and drive the connecting part 24 to move. After one of the heavy objects 3 in the working group is pulled up, the upper half of the cable 21 or the lower half of the cable 22 located on the side of another heavy object 3 on the winding reel 43 will be unwound. At this time, by placing the cable 2 at the connecting part 24 into the receiving groove 84, and by driving the connecting part 24 and the cable 2 closer to the end limit device 6 of the heavy object through the traction base 81, the upper half of the cable 21 or the lower half of the cable 22 is connected to the cable 23 of the heavy object at this location.

[0046] Preferably, two reel-type power generation mechanisms 4 are provided, arranged vertically. By providing two reel-type power generation mechanisms 4, the cable 2 can be prevented from getting tangled. When the turntable 41 corresponding to the upper or lower reel-type power generation mechanism 4 rotates, the quick-release head 25 and the connecting part 24 are disassembled or assembled, and the quick-release head 25 is limited by the plug block 64, the reel 43 of the other reel-type power generation mechanism 4 can be wound or unwound simultaneously. This avoids the time wasted when one reel-type power generation mechanism 4 is rotating or stopped, allowing the process of the weight 3 sinking to generate electricity and pulling up to store energy to proceed continuously, thus improving efficiency.

[0047] Furthermore, a pulley frame 411 is provided on the turntable 41, and a pulley 412 is rotatably mounted on the pulley frame 411. The upper half cable 21 and the lower half cable 22 pass through the lower surface of the pulley 412. With this arrangement, the starting ends of the upper half cable 21 and the lower half cable 22 are both fixed at the bottom of the winding reel 43. The upper half cable 21 and the lower half cable 22 are both wound or unwound from the bottom of the winding reel 43, which serves as a guide for the upper half cable 21 and the lower half cable 22.

[0048] Furthermore, the initial and final positions of the weight 3 are both in the seawater, while the final position of the weight 3 is on the seabed. This avoids changes in buoyancy when the weight 3 enters and leaves the water, ensuring that the power generation process is not affected by fluctuations and that the power generation is more stable. After all the weights 3 are lowered to the seabed, the installation platform can be anchored to resist extreme weather such as typhoons.

[0049] In this invention, when there is only one reel-type power generation mechanism 4, during the power generation process of the weight 3 sinking, the power generation is achieved by... Figure 1 Taking 20 heavy objects 3 as an example, firstly, the upper half cable 21 and the lower half cable 22 are connected to the corresponding heavy object cable 23. At this time, the heavy object cable 23 is limited by the initial limit device 5 of the heavy object through the quick-release head 25. Then, the plug 64 of the initial limit device 5 of the heavy object on the side of the upper half cable 21 is pulled out, so that the heavy object cable 23 and the connected upper half cable 21 sink into the seawater under the gravity of the heavy object 3 to generate electricity. At this time, as the reel 43 rotates, the lower half cable 22 piled on the installation platform 1 will be wound on the reel 43. Theoretically, the weight of the heavy object cable 23 between the initial limit device 5 and the final limit device 6 is equal to the depth of the seabed, and theoretically, the length of the lower half cable 22 piled on the installation platform 1 is equal to the depth of the seabed, usually not exceeding 200. The nearshore area at a depth of meters serves as the location of the installation platform 1. When the weight 3 sinks to the seabed, the quick-release head 25 and the connecting part 24 will move to approximately the position of the weight end limit device 6. At this time, the connecting part 24 and the quick-release head 25 are disassembled, and the lower half cable 22 is already wound on the reel 43. Then, the corresponding weight 3 at the lower half cable 22 is sunk to generate electricity. At this time, the upper half cable 21 on the installation platform 1 will be wound on the reel 43. After the weight 3 sinks to the bottom, similarly, the quick-release head 25 and the connecting part 24 are disassembled, and the quick-release head 25 is limited by the weight end limit device 6, thereby fixing the weight 3 that has sunk to the seabed. Then, by rotating the turntable 41 by 18 degrees each time, the two weights 3 in other working groups can be sunk to generate electricity in sequence. The difference between setting up two reel power generation mechanisms 4 and setting up one reel power generation mechanism 4 is that it can perform continuous power generation or energy storage operations, and there will be no time wastage due to the rotation of the reel 41, the disassembly and assembly of the quick-release head 25 and the connecting part 24, and the limiting of the quick-release head 25 by the insert block 64. Specifically, with Figure 6Taking 20 weights 3 as an example, the rotation angle of both the upper and lower turntables 41 is 36 degrees. Furthermore, the height of the initial weight limit device 5 and the final weight limit device 6 corresponding to the lower winding reel 43 will be slightly lower. After the last weight 3 is lowered onto each of the upper and lower turntables 41, there is no need to disassemble the quick-release head 25 and the connecting part 24 at the position of the final weight limit device 6; the quick-release head 25 and the connecting part 24 can be directly limited by the final weight limit device 6.

[0050] Taking the setup of two reel-type power generation mechanisms 4 as an example, during the energy storage process of the weight 3 pulling up the energy storage, see... Figure 7 In the initial state of energy storage for lifting weight 3, the drive motor 44 winds up the reel 43, causing the upper half of the cable 21 to be wound up, thus lifting weight 3. The lower half of the cable 22 is unwound, and the cable traction device 8 pulls the lower half of the cable 22 to the weight's final limit device 6. After completing energy storage for lifting one weight 3 in the same work group on the upper turntable 41, or during the process of energy storage for lifting weight 3 on the upper turntable 41, the lifting operation for another weight 3 in the lower turntable 41 is then performed. The upper half of the cable 21 and the weight cable 23 of the upper turntable 41 are detached and separated. The quick-release head 25 of the weight cable 23 is limited by the initial weight limit device 5. At this time, the upper turntable 41 is connected to the quick-release head 25 at the connection part 24 of the final weight limit device 6. The other weight 3 in the upper turntable 41 is then wound up and pulled up. It can be understood that after completing the pulling up of the two weights 3 in their respective working groups, the upper and lower turntables 41 rotate 36 degrees each time until all weights 3 are pulled up. By setting up the upper and lower turntables 41, the power generation and energy storage process is made continuous, without any additional time waste.

[0051] In this invention, the physical relationships in the energy storage and power generation process of a single heavy object and the derivation of the overall system's power generation are as follows:

[0052] 1. Force analysis of the heavy object:

[0053] In this system, assuming the weight is a sphere, the sphere experiences four forces as it falls, as follows: gravity G, flow resistance F... 阻 buoyancy F 浮 Tension F 拉 ;

[0054] After the sphere is fully submerged in water, its weight and buoyancy remain unchanged. Flow resistance is related to the descent speed, while the pulling force is equal to the magnitude of the remaining net force, but in the opposite direction. The specific formula is as follows:

[0055] Flow resistance F 阻 Calculation formula:

[0056] ρ: fluid density, kg / m³ 3 ;

[0057] v: velocity of the falling object, m / s;

[0058] C d : Drag coefficient (drag factor, dimensionless, related to Re);

[0059] A: Maximum cross-sectional area of ​​the sphere in the direction of its fall, in meters. 2 ;

[0060] Reynolds number Re is calculated using the following formula:

[0061] d: Diameter of the sphere, in meters;

[0062] μ: hydrodynamic viscosity, kg / m³ -1 s -1 ;

[0063] If no tension is applied, will the ball continue to accelerate as it falls? That is, will the ball's final velocity, v, be the same? t It will approach infinity, for which the following calculations are made:

[0064] If the tension is set to 0, then: G=F 阻 +F 浮 Then it can be simplified to:

[0065] g is the acceleration due to gravity, taken as 9.81 m / s². 2 ;ρ 球 Density of a sphere, kg / m³ 3 ;

[0066] From this formula, we can see that the terminal velocity v of the falling sphere is... t With ρ 球 It is positively correlated with the sphere diameter d and with the drag coefficient C. d It is negatively correlated with fluid density ρ.

[0067] For example: A 100-ton sphere has a density of 3000 kg / m³. 3 The density of seawater is taken as 1025 kg / m³. 3 Assuming the ambient temperature is 20℃, the dynamic viscosity of seawater μ is taken as 1.05 × 10⁻⁶. -3 kgm -1 s -1 Then the terminal speed v t The calculated value is approximately 22.4 m / s.

[0068] Therefore, the maximum speed of a 100-ton sphere at this sphere density is 22.4 m / s, after which it stops accelerating and becomes uniform in motion. Thus, it can be known that the sphere's falling speed varies between 0 and 22.4 m / s.

[0069] 2. Calculation and analysis of the theoretical cycle efficiency of the system:

[0070] If we compare offshore gravity energy storage systems to pumped-storage systems, we can determine their system efficiency as follows:

[0071] Ignoring rope friction and generator / motor efficiency losses, and ensuring uniform motion, considering only the effect of flow resistance, we have:

[0072] When a heavy object falls to generate electricity, it is considered that all the pulling force applied to the heavy object is converted into the input force that pulls the power generation equipment, i.e., electromagnetic damping F. 阻磁 Then we have: F 阻磁 =GF 浮 -F 阻 When the weight is rising and storing energy, the flow resistance is opposite, and the pulling force is F. 拉 =GF 浮 +F 阻 .

[0073] The total power output during the descent phase of power generation is W. 出 Then we have: W 出= F 阻磁 ×H

[0074] The total internal work input during the rising energy storage phase is W 入 Then we have: W 入= F 拉 ×H

[0075] That is, the ideal cycle efficiency of the system is:

[0076] Assuming the rising and falling speeds are constant, this formula can be used to represent the system efficiency. Taking a 100-ton sphere as an example, calculations show that the system is most efficient when the sphere moves at low speed. As the speed increases, the flow resistance increases quadratically, which has a significant impact on the system efficiency.

[0077] Falling speed m / s Flow resistance N Ideal cycle efficiency of the system % 0.1 12.8 99.996 1 1410 99.56 10 141000 64.2 22.4 564000 6.8

[0078] When the upward and downward velocities are not uniform, the ideal cycle efficiency of the system is as follows:

[0079] Among them, let ,set up As can be seen from the formula, even when the system is in non-uniform motion, the above conclusion remains unchanged, that is: the system is most efficient when the sphere is moving at a low speed.

[0080] 3. Initial acceleration motion analysis of the weight:

[0081] The previous calculations assumed uniform motion throughout the entire trajectory. However, considering the actual situation, there will be an acceleration time and acceleration distance. Let the target's descent velocity be V, and the acceleration distance be S. Then:

[0082] That is, the target speed V is positively correlated with the acceleration stroke S. The smaller the target speed, the smaller the acceleration stroke. Assuming the target speed V is 0.5 m / s, the acceleration stroke is 0.02 m, which can be almost ignored in engineering.

[0083] In the current system, the target speed can be locked by adjusting the magnitude of the electromagnetic damping on the generator, which is mainly divided into the following three stages.

[0084] Accelerating the grid connection segment: Allow the heavy object to fall naturally, reaching the target speed under its own combined force;

[0085] Uniform speed power generation section: The current at the generator is connected to the grid, and electromagnetic damping is used to make the electromagnetic damping F 阻磁 The magnitude is equal to the magnitude of the current net force on the object;

[0086] Deceleration and stopping section: Increase the electromagnetic damping of the generator so that the resultant force of the weight is upward, and finally the weight comes to a smooth stop on the seabed.

[0087] The acceleration is as follows:

[0088] Among them, electromagnetic damping F 阻磁 When the value is 0, it represents the weight falling naturally, and the generator is idling without generating electricity; after the generator generates electricity and is connected to the grid, the electromagnetic damping is as follows:

[0089] F 阻磁 =G 净 -F 阻 .

[0090] 4. Power generation analysis of offshore gravity energy storage systems:

[0091] Electromagnetic damping is F 阻磁 =G 净 -F 阻 That is, the pulling force on the weight in the system is entirely converted into electromagnetic damping F to overcome the generator's power generation. 阻磁 Considering the kinetic energy recovery during system shutdown, we have:

[0092] System single-time output electrical energy W出 =Electrical energy output from the constant-speed power generation section + kinetic energy recovery from the deceleration and shutdown section

[0093]

[0094]

[0095] Taking a 100-ton load as an example, when the descent speed is ≤2m / s, the kinetic energy accounts for less than 0.04% of the output electrical energy, which can be ignored. When the total stroke is 200m, the acceleration stroke S≤0.31m, accounting for less than 0.16% of the total stroke, which can also be ignored.

[0096] The generator is a conventional permanent magnet generator, with a typical mechanical efficiency of 95-97%, the reducer efficiency of 92-98%, and the motor efficiency of 95-98%. Considering mechanical efficiency losses and neglecting rope friction, the actual efficiencies are as follows:

[0097]

[0098] Assuming the efficiency of the reducer, motor, and generator are all 95%, then:

[0099]

[0100] Assuming the profit efficiency η is the sum of the peak electricity generation price and the off-peak electricity consumption price, then the profit efficiency η is calculated as the ratio of peak electricity generation price to off-peak electricity consumption price. 利 Then we have:

[0101]

[0102] The ratio of peak electricity price to off-peak electricity price for domestic industrial and commercial users is generally 3-4 times, with a value of 3.5 times. Substituting this into the above formula, we can see that:

[0103]

[0104] 5. Reel radius R, reduction ratio i, electromagnetic damping F 阻磁 Power generation P and power generation W 电 Analysis:

[0105] If the pulling force on the weight is entirely converted into electromagnetic damping, then the torque T of the pulling force on the reel is... 卷 All of this is converted into the input torque to the generator: T 卷= F 阻磁 ×R.

[0106] When the descent speed remains constant, the larger the value of R, the slower the reel rotates, and the greater the torque T on the reel. 卷The larger the value of R, the larger the required reduction ratio i of the reducer (i.e., the larger the reduction ratio i, the higher the speed increase and the faster the generator speed). This requires an increase in the number of transmission stages in the reducer. More stages result in lower mechanical efficiency, higher cost, and more potential failure points. Conversely, the smaller the value of R, the lower the requirements for the reducer's torque and reduction ratio, resulting in lower cost and higher efficiency.

[0107] The input torque of the generator is then:

[0108]

[0109] The descent speed V of the sphere and the generator speed n 发( The relationship between r / min is:

[0110] It can be seen that once the descent speed is constant, the generator speed is constant, thus making it suitable for permanent magnet synchronous generators.

[0111] The generator's input power P (kW) is:

[0112] 9550 is the conversion constant, specifically:

[0113] Considering the mechanical efficiency η of the generator 发 Then the actual power generation P 实 :

[0114]

[0115] Fall time t 坠 For: t 坠 =S 总 / V

[0116] Final output electrical energy W 电 (kWh) is:

[0117]

[0118] The above formula analysis shows that the final power generation is not directly related to the generator's rotational speed, but only to its mechanical efficiency. Specifically, the impact on generator mechanical efficiency means that the generator's load rate needs to be near its rated load rate; both excessively high and excessively low load rates will reduce the generator's mechanical efficiency. The general formula for load rate is as follows:

[0119] Load rate = Actual output power / Rated motor power

[0120] Actual output power refers to the electrical power output by the generator. Therefore, the optimal choice between using a few high-power generators and using many low-power generators depends on which option has the optimal load rate. If the rated power of a single high-power generator is within 1.25-1.67 times the estimated actual power output, then using a single high-power generator is the optimal solution. For example, with a 100-ton load and a descent speed of 1 m / s, the final power output would be approximately 575 kW. In this case, selecting a single generator with a rated power of 718.75-960.25 kW would be the optimal solution.

[0121] In this system, N 重 Taking a heavy object as an example, the final total power generation W 总 Then it is:

[0122]

[0123] From the formula for the final output power generation above, it can be seen that the speed of descent V mainly affects the power generation by a faster descent rate. In other words, a slow descent does not affect the final power generation; on the contrary, it can increase it. The overall power generation of the system is only related to the number of weights; the more weights, the more power generation. Because this system involves continuous power generation or storage, compared to traditional systems where the next weight must stop before the next weight can begin its energy storage or generation process, there is no wasted time during the energy storage or generation process. This results in a higher power generation per unit time compared to traditional systems. In other words, the actual power generation P of a single weight in this system is higher. 实 This refers to the actual power generation of the entire system.

[0124] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A marine gravity energy storage system, comprising an installation platform (1) and a weight (3) traction-driven by a cable (2), the weight (3) being capable of moving up and down relative to the installation platform (1) in seawater, characterized in that, Multiple weights (3) are arranged around the circumference of the mounting platform (1). The number of weights (3) is an even multiple. Two weights (3) arranged opposite each other in the radial direction of the mounting platform (1) form a working group. A reel generator mechanism (4) is provided on the mounting platform (1). The reel generator mechanism (4) includes a turntable (41) rotatably mounted on the mounting platform (1), a bracket (42) fixedly mounted on the turntable (41), a reel (43) rotatably mounted on the bracket (42), a drive motor (44) located on one side of the reel (43) and capable of driving the reel (43) to rotate, and a generator (45) located on the other side of the reel (43) and driven by the rotation of the reel (43) to generate electricity. The cable (2) includes an upper half cable (21) that can be wound around the upper half of the reel (43), a lower half cable (22) that can be wound around the lower half of the reel (43), and a cable that is connected to the weights (3). The heavy cable (23) is connected to the upper half cable (21) and the lower half cable (22) are both fixed at the bottom of the reel (43) at the starting end of the reel (43). When one of the upper half cable (21) and the lower half cable (22) is unwound by the reel (43), the other will be wound into the reel (43). The ends of the upper half cable (21) and the lower half cable (22) away from the reel (43) are provided with connecting parts (2). 4) A quick-release head (25) is provided at the end of the heavy object cable (23) away from the heavy object (3). The quick-release head (25) is detachably connected to the connecting part (24). The installation platform (1) is provided with a heavy object initial limit device (5) near the winding reel (43) and a heavy object final limit device (6) away from the winding reel (43). Both the heavy object initial limit device (5) and the heavy object final limit device (6) can limit the quick-release head (25).

2. The offshore gravity energy storage system according to claim 1, characterized in that, Both sides of the winding reel (43) are provided with transmission gears (46). The drive motor (44) is connected to a motor coupling (47). The motor coupling (47) is connected to a motor gear (48). The motor gear (48) can be directly or indirectly meshed with the transmission gear (46) on one side of the winding reel (43). The generator (45) is connected to a generator coupling (49). The generator coupling (49) is connected to a generator gear (50). The generator gear (50) can be directly or indirectly meshed with the transmission gear (46) on the other side of the winding reel (43).

3. The offshore gravity energy storage system according to claim 2, characterized in that, The connecting part (24) is inserted into the quick-release head (25) to achieve a detachable connection with the quick-release head (25), or the connecting part (24) is screwed into the quick-release head (25) to achieve a detachable connection with the quick-release head (25).

4. The offshore gravity energy storage system according to claim 3, characterized in that, Both the initial weight limiting device (5) and the final weight limiting device (6) include a limiting seat (61), an insertion port (62) provided on the limiting seat (61), a passage port (63) provided on the limiting seat (61) that allows the quick-release head (25) to pass through, and a plug (64) that can be inserted into the insertion port (62) and reduces the passage area of ​​the passage port (63). The plug (64) is provided with a limiting port (65) that can be arranged opposite to the passage port (63).

5. A marine gravity energy storage system according to claim 1, 2, 3, or 4, characterized in that, At least one set of cable support devices (7) is provided on the installation platform (1) between the initial limit device (5) and the final limit device (6) of the heavy object. Each set of cable support devices (7) includes two cable support units (71). Each cable support unit (71) includes a movable support base (72), a lifting cylinder (73) on the support base (72), a guide slide (74) at the end of the lifting cylinder (73) that can guide the cable (2), and a position sensor (75) on the support base (72).

6. A marine gravity energy storage system according to claim 5, characterized in that, The installation platform (1) is equipped with a cable traction device (8). The cable traction device (8) includes a movably traction base (81), a traction cylinder (82) mounted on the traction base (81) and capable of being raised and lowered, and a traction head (83) located at the end of the traction cylinder (82). The traction head (83) is provided with a receiving groove (84) for accommodating the cable (2). The traction head (83) can abut against the connecting part (24) and drive the connecting part (24) to move.

7. A marine gravity energy storage system according to claim 6, characterized in that, At least two reel power generation mechanisms (4) are provided, and multiple reel power generation mechanisms (4) are arranged in layers in the vertical direction so that the power generation or energy storage process can be carried out continuously.

8. A marine gravity energy storage system according to claim 7, characterized in that, A pulley frame (411) is provided on the turntable (41), and a pulley (412) is rotatably provided on the pulley frame (411). The upper half cable (21) and the lower half cable (22) pass through the lower surface of the pulley (412).

9. A marine gravity energy storage system according to claim 1, characterized in that, The initial and final positions of the weight (3) are both in the seawater.

10. A marine gravity energy storage system according to claim 9, characterized in that, The final position of the weight (3) is located on the seabed, which can anchor the installation platform (1) in extreme weather.

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