Buoyancy energy storage system and method

Abstract

The present invention relates to the field of buoyancy energy storage technology, and in particular to a buoyancy energy storage system and method. The system comprises: a frame, which is arranged in water, a platform is arranged on the top of the frame, the platform is higher than the water surface, and the frame comprises a plurality of lifting units; a plurality of motor units, which are arranged on the platform, each motor unit corresponds to a lifting unit, and each motor unit comprises an electric motor, a generator and a transmission assembly; a plurality of floating units, each floating unit is arranged in a lifting unit, each floating unit comprises a floating body and a fixing assembly for fixing the floating body, and the fixing assembly is connected to the transmission assembly; a control unit, which is electrically connected to an external new energy power generation unit and the motor unit, and the control unit is used to control the output of electric energy from the new energy power generation unit to the motor corresponding to each floating unit based on the storable electric energy of each floating unit. The technical solution of the present invention can realize frequency modulation when the power fluctuation amplitude of the power grid is relatively small.

Description

Technical Field

[0001] The present invention relates to the technical field of buoyancy energy storage, and in particular to a buoyancy energy storage system and method. Background Art

[0002] Renewable energy generation suffers from significant intermittency and volatility, making it impossible to directly connect to the power grid. This makes power balancing difficult and makes wind curtailment and power rationing very common in some areas. Therefore, the storage and utilization of energy through energy storage technologies is a major research direction in the development of new energy.

[0003] Related technologies, such as patent publication number CN113669192A, disclose a marine buoyancy energy storage system. Specifically, during the energy storage phase, a buoyant ball is lowered from a surface platform to the seabed by an electric motor via a closed cable, converting excess electrical energy into the ball's buoyancy potential energy for storage. During the energy release phase, the ball rises from the seabed to the surface platform and, via the closed cable, pulls a generator to generate electricity. However, this technical solution struggles to achieve frequency modulation when grid power fluctuations are relatively small.

[0004] Therefore, there is an urgent need for a buoyancy energy storage system and method to solve the above problems. Summary of the Invention

[0005] The embodiments of the present invention describe a buoyancy energy storage system and method, which can achieve frequency modulation when the power fluctuation amplitude of the power grid is relatively small.

[0006] In a first aspect, an embodiment of the present invention provides a buoyancy energy storage system, comprising:

[0007] A frame is disposed in the water, a platform is provided on the top of the frame, the platform is above the water surface, and the frame includes a plurality of lifting units;

[0008] A plurality of motor units are arranged on the platform, each of the motor units corresponds to one of the lifting units, and each of the motor units includes an electric motor, a generator and a transmission assembly;

[0009] a plurality of floating units, each of the floating units being disposed in one of the lifting units, each of the floating units comprising a floating body and a fixing assembly for fixing the floating body, the fixing assembly being connected to the transmission assembly;

[0010] A control unit is electrically connected to the external new energy power generation unit and the motor unit. The control unit is used to control the output of electric energy from the new energy power generation unit to the motor corresponding to each of the floating units based on the storable electric energy of each of the floating units.

[0011] In a second aspect, an embodiment of the present invention provides a buoyancy energy storage method, based on the buoyancy energy storage system described in the above embodiment, the method comprising:

[0012] During the energy storage stage, the control unit controls the motor to connect with the transmission assembly, and controls the new energy power generation unit to supply power to the motor, so that the motor drives the transmission assembly to move, and drives the floating body unit to move downward along the lifting unit through the transmission assembly, thereby converting the electrical energy generated by the new energy power generation unit into the buoyancy potential energy of the floating body;

[0013] During the energy release phase, the control unit controls the connection between the generator and the transmission assembly, and the floating body with buoyancy potential energy moves upward to drive the transmission assembly to move through the fixed assembly, thereby driving the generator to generate electricity.

[0014] According to the buoyancy energy storage system and method provided by the embodiments of the present invention, since the rated power emitted by a single buoyancy ball is relatively large, it cannot respond to or has a poor response effect for small power fluctuations in the power grid; while the rated power emitted by multiple floating units is relatively small, and a better frequency regulation effect can be achieved for small power fluctuations in the power grid. When the power fluctuation amplitude of the power grid is large, controlling multiple floating units for frequency regulation can also achieve the expected effect; in addition, by using the frame, the stability of each floating unit during the lifting process along the lifting unit can be guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 A schematic structural diagram of a buoyancy energy storage system according to one embodiment is shown;

[0017] Figure 2 Shown Figure 1 A schematic structural diagram of a motor unit in the buoyancy energy storage system shown;

[0018] Figure 3 Shown Figure 1 A partial enlarged view of a floating unit in the buoyancy energy storage system shown;

[0019] Figure 4 Shown Figure 1 A top view of a floating unit in the buoyancy energy storage system is shown.

[0020] Reference numerals:

[0021] 1-frame;

[0022] 11-Platform;

[0023] 12-lifting unit;

[0024] 121-limiting track;

[0025] 2-motor unit;

[0026] 21-electric motor;

[0027] 22- generator;

[0028] 23- transmission assembly;

[0029] 231-Electromagnetic clutch;

[0030] 232-gear assembly;

[0031] 233- transmission parts;

[0032] 3- floating unit;

[0033] 31-Floating body;

[0034] 32-Fixed component;

[0035] 321-limiting block;

[0036] 322-roller;

[0037] 323-fixed part;

[0038] 324-fixing parts;

[0039] 325-Fixed shell. DETAILED DESCRIPTION

[0040] The solution provided by the present invention is described below with reference to the accompanying drawings.

[0041] like Figures 1 to 4 As shown, an embodiment of the present invention provides a buoyancy energy storage system, which includes a frame 1, multiple motor units 2, multiple floating units 3 and a control unit (not shown in the figure), wherein:

[0042] The frame 1 is set in the water, and a platform 11 is set on the top of the frame 1. The platform 11 is higher than the water surface. The frame 1 includes a plurality of lifting units 12;

[0043] A plurality of motor units 2 are provided on the platform 11 , each motor unit 2 corresponds to a lifting unit 12 , and each motor unit 2 includes an electric motor 21 , a generator 22 and a transmission assembly 23 ;

[0044] Each floating unit 3 is disposed in a lifting unit 12 , and each floating unit 3 includes a floating body 31 and a fixing assembly 32 for fixing the floating body 31 , and the fixing assembly 32 is connected to the transmission assembly 23 ;

[0045] The control unit is electrically connected to an external new energy power generation unit (not shown in the figure) and the motor unit 2. The control unit is used to control the output of electric energy from the new energy power generation unit to the motor 21 corresponding to each floating unit 3 based on the storable electric energy of each floating unit 3.

[0046] In this embodiment, since the rated power emitted by a single buoyancy ball is relatively large, it cannot respond to or has a poor response effect on small power fluctuations in the power grid; while the rated power emitted by multiple floating units 3 is relatively small, and a better frequency regulation effect can be achieved for small power fluctuations in the power grid. When the power fluctuation amplitude of the power grid is large, controlling multiple floating units 3 for frequency regulation can also achieve the expected effect; in addition, by using the frame 1, the stability of each floating unit 3 during the lifting process along the lifting unit 12 can be guaranteed.

[0047] In one embodiment of the present invention, each lifting unit 12 is provided with a limiting rail 121 arranged along the vertical direction, and the fixing component 32 of each floating unit 3 is provided with a limiting block 321, which can move up and down along the limiting rail 121.

[0048] In this embodiment, by providing the limiting blocks 321 and the limiting rails 121 , the stability of each floating unit 3 during the lifting process along the lifting unit 12 can be ensured.

[0049] like Figure 4 As shown, each lifting unit 12 is provided with four limiting rails 121 arranged along the vertical direction, which is more conducive to ensuring the stability of each floating unit 3 during the lifting process along the lifting unit 12.

[0050] In one embodiment of the present invention, the fixing assembly 32 of each floating unit 3 is provided with a roller 322, which contacts the limiting rail 121. This arrangement can effectively prevent each floating unit 3 from being "stuck" during the lifting process along the lifting unit 12.

[0051] In one embodiment of the present invention, the transmission assembly 23 includes an electromagnetic clutch 231, a gear assembly 232 meshing with the electromagnetic clutch 231, and a transmission member 233 connected to the gear assembly 232, and the transmission member 233 is connected to the fixed assembly 32;

[0052] During the energy storage phase, the control unit controls the motor 21 to connect with the electromagnetic clutch 231;

[0053] During the energy discharging stage, the control unit controls the generator 22 to connect with the electromagnetic clutch 231 .

[0054] In this embodiment, the electromagnetic clutch 231 is provided to achieve smooth switching between energy storage and energy release.

[0055] In one embodiment of the present invention, the transmission member 233 is a chain or a wire rope (not shown);

[0056] When the transmission member 233 is a chain, the fixing assembly 32 is provided with a fixing portion 323, which is a vertically penetrating structure. A fixing member 324 for passing the chain is provided in the fixing portion 323, and the transmission member 233 and the fixing portion 323 are fixed by the fixing member 324.

[0057] In this embodiment, by setting the transmission member 233 as a chain, the chain structure can be used to facilitate fixation with the fixing component 32, specifically, the fixing member 324 is passed through the transmission member 233 located in the fixing part 323 to achieve fixation of the two.

[0058] In some embodiments, the fixing member 324 may be a bolt.

[0059] In one embodiment of the present invention, the fixing assembly 32 includes a fixing shell 325, which is provided with internal threads (not shown). The floating body 31 is provided with external threads (not shown). The floating body 31 and the fixing shell 325 are fixed together by the threads. This arrangement helps ensure the stability of the fixing between the floating body 31 and the fixing shell 325, thereby effectively preventing the floating body 31 and the fixing shell 325 from separating when the buoyancy increases.

[0060] In some embodiments, in order to facilitate the installation of the fixing assembly 32 and the floating body 31 , the fixing shell 325 may be configured as a split structure, for example, consisting of two half shells fastened by bolts.

[0061] In one embodiment of the present invention, both the upper end surface and the lower end surface of the floating body 31 are tapered surfaces. This configuration can reduce the resistance during the lifting and lowering process of the floating body 31, thereby saving energy consumption.

[0062] In one embodiment of the present invention, the frame 1 is a steel frame structure that has undergone marine anti-corrosion and anti-fouling treatment. This configuration effectively ensures the service life of the frame 1. The embodiment of the present invention does not further describe the marine anti-corrosion and anti-fouling treatment, as it is well known to those skilled in the art.

[0063] In one embodiment of the present invention, the new energy power generation unit is a solar power generation unit, a wind power generation unit or an ocean power generation unit, which is not specifically limited in this embodiment of the present invention.

[0064] In one embodiment of the present invention, the float 31 is a hollow structure filled with a gas having a density no greater than that of air. Among all the floats 31, there are at least two types of floats 31 filled with gases of different densities. Each float unit 3 has two states of minimum and maximum buoyancy potential energy, and the storable electrical energy of each float unit 3 is equal to the maximum buoyancy potential energy of the float unit 3.

[0065] The control unit is configured to perform the following operations when controlling the new energy generation unit to output electric energy to the motor 21 corresponding to each floating unit 3 based on the storable electric energy of each floating unit 3:

[0066] When the output power of the new energy power generation unit is greater than the sum of the storable power of all the floating units 3, the output power of the new energy power generation unit to the motor 21 corresponding to each floating unit 3 is determined as the storable power of the current floating unit 3;

[0067] When the output electric energy of the new energy power generation unit is not greater than the sum of the storable electric energy of all the floating units 3, the following are executed: all the floating units 3 with the same storable electric energy are divided into a floating unit set; the proportion of the total storable electric energy of each floating unit set to the total storable electric energy of all the floating unit sets is determined; the output electric energy of the new energy power generation unit is distributed to each floating unit set according to the proportion of each floating unit set; for each floating unit set, the electric energy allocated to the current floating unit set is distributed to each floating unit 3 in the floating unit set in turn; wherein the electric energy allocated to the floating unit 3 is storable electric energy, and the excess electric energy that cannot meet the requirement that the electric energy allocated to the floating unit 3 is storable electric energy is discarded.

[0068] In this embodiment, in order to better achieve frequency regulation when the power grid fluctuation amplitude is relatively small, it can be considered to fill different floats 31 with gases of different densities, so that there are at least two floats 31 filled with gases of different densities among all floats 31. In this way, when the output power of the new energy power generation unit is not greater than the sum of the storable power of all float units 3, the above-mentioned power distribution strategy can be used to further improve the frequency regulation effect when the power grid fluctuation amplitude is relatively small.

[0069] In one embodiment of the present invention, each lifting unit 12 is provided with a locking device (not shown in the figure), which is used to suspend the floating unit 3 at the current position;

[0070] Each floating unit 3 has two states of minimum and maximum buoyancy potential energy. The storable electrical energy of each floating unit 3 is greater than the minimum buoyancy potential energy and less than or equal to the maximum buoyancy potential energy.

[0071] In this embodiment, by providing a locking device, the floating unit 3 can be suspended at any position between the position of minimum buoyancy potential energy and the position of maximum buoyancy potential energy, thereby further improving the frequency regulation effect when the power grid power fluctuation amplitude is relatively small.

[0072] In some embodiments, the locking device may be a rack and pinion structure. This structure has the following characteristics: it can move normally in one direction (e.g., downward), but cannot move in the opposite direction (e.g., upward). To achieve the opposite direction of movement, the restriction of the relevant structure must be released, so that normal movement in the opposite direction can be achieved. The specific structure of the locking device is not limited in this embodiment of the present invention.

[0073] In one embodiment of the present invention, the control unit is configured to perform the following operations when controlling the new energy generation unit to output electric energy to the motor 21 corresponding to each floating unit 3 based on the storable electric energy of each floating unit 3:

[0074] When the output power of the new energy power generation unit is greater than the sum of the storable power of all the floating units 3, the output power of the new energy power generation unit to the motor 21 corresponding to each floating unit 3 is determined as the storable power of the current floating unit 3;

[0075] When the output electric energy of the new energy power generation unit is not greater than the sum of the storable electric energy of all the floating units 3, the following are executed: all the floating units 3 with the same storable electric energy are divided into a floating unit set; the proportion of the total storable electric energy of each floating unit set to the total storable electric energy of all the floating unit sets is determined; the output electric energy of the new energy power generation unit is distributed to each floating unit set according to the proportion of each floating unit set; for each floating unit set, the electric energy allocated to the current floating unit set is distributed to each floating unit 3 in the floating unit set in turn; wherein, the floating unit 3 whose allocated electric energy is storable electric energy is in the maximum buoyancy potential energy state, and the floating unit 3 whose allocated electric energy is less than the storable electric energy is between the minimum buoyancy potential energy state and the maximum buoyancy potential energy state.

[0076] In this embodiment, to better achieve frequency regulation when grid power fluctuations are relatively small, a locking device can be installed on each lifting unit 12. This allows the aforementioned energy distribution strategy to further enhance the frequency regulation effect during periods of relatively small grid power fluctuations, provided the output power of the new energy generation unit is no greater than the sum of the storable power of all floating units 3. Furthermore, compared to a solution in which at least two of the floating units 31 are filled with gases of different densities, this solution eliminates the need to discard excess energy that cannot be allocated to the floating units 3 as storable energy, thereby reducing energy waste.

[0077] In addition, an embodiment of the present invention further provides a buoyancy energy storage method. Based on the buoyancy energy storage system mentioned in the above embodiment, the method includes:

[0078] During the energy storage stage, the control unit controls the connection between the motor 21 and the transmission assembly 23, and controls the new energy power generation unit to supply power to the motor 21, so that the motor 21 drives the transmission assembly 23 to move, and drives the floating unit 3 to move downward along the lifting unit 12 through the transmission assembly 23, thereby converting the electrical energy generated by the new energy power generation unit into the buoyancy potential energy of the floating body 31;

[0079] During the energy release phase, the control unit controls the connection between the generator 22 and the transmission assembly 23, and the float 31 with buoyancy potential energy moves upward to drive the transmission assembly 23 to move through the fixing assembly 32, thereby driving the generator 22 to generate electricity.

[0080] It is understandable that the buoyancy energy storage method provided in this embodiment and the buoyancy energy storage system provided in the above embodiment are based on the same inventive concept, and therefore both have the same beneficial effects, which will not be described in detail here.

[0081] It should be noted that, in this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A buoyancy energy storage system, characterized in that: include: A frame (1) is disposed in water, a platform (11) is provided on the top of the frame (1), the platform (11) is above the water surface, and the frame (1) includes a plurality of lifting units (12); A plurality of motor units (2) are arranged on the platform (11), each motor unit (2) corresponds to one lifting unit (12), and each motor unit (2) includes an electric motor (21), a generator (22), and a transmission assembly (23); A plurality of floating body units (3), each of the floating body units (3) being disposed in one of the lifting units (12), each of the floating body units (3) comprising a floating body (31) and a fixing assembly (32) for fixing the floating body (31), the fixing assembly (32) being connected to the transmission assembly (23); a control unit electrically connected to an external new energy power generation unit and the motor unit (2), the control unit being used to control the output of electric energy from the new energy power generation unit to the motor (21) corresponding to each of the floating units (3) based on the storable electric energy of each of the floating units (3); The floating body (31) is a hollow structure, and the floating body (31) is filled with a gas having a density not greater than that of air; among all the floating bodies (31), there are at least two floating bodies (31) filled with gases of different densities; each of the floating body units (3) has two states of minimum and maximum buoyancy potential energy, and the storable electrical energy of each of the floating body units (3) is equal to the maximum buoyancy potential energy of the floating body unit (3); The control unit is used to perform the following operations when controlling the output of electric energy from the new energy generation unit to the motor (21) corresponding to each of the floating units (3) based on the storable electric energy of each of the floating units (3): When the output electric energy of the new energy power generation unit is greater than the sum of the storable electric energy of all the floating units (3), the output electric energy of the new energy power generation unit to the motor (21) corresponding to each of the floating units (3) is determined as the storable electric energy of the current floating unit (3); When the output electric energy of the new energy power generation unit is not greater than the sum of the storable electric energy of all the floating units (3), the following steps are performed: dividing all the floating units (3) with the same storable electric energy into a floating unit set; determining the proportion of the total storable electric energy of each floating unit set to the total storable electric energy of all the floating unit sets; allocating the output electric energy of the new energy power generation unit to each floating unit set according to the proportion of each floating unit set; for each floating unit set, allocating the electric energy allocated to the current floating unit set to each floating unit (3) in the floating unit set in turn; wherein the electric energy allocated to the floating unit (3) is storable electric energy, and the excess electric energy that cannot satisfy the requirement that the electric energy allocated to the floating unit (3) is storable electric energy is discarded; Each lifting unit (12) is provided with a locking device, and the locking device is used to suspend the floating unit (3) at a current position; Each of the floating units (3) has two states of minimum and maximum buoyancy potential energy, and the storable electrical energy of each of the floating units (3) is greater than the minimum buoyancy potential energy and less than or equal to the maximum buoyancy potential energy; The control unit is used to perform the following operations when controlling the output of electric energy from the new energy generation unit to the motor (21) corresponding to each of the floating units (3) based on the storable electric energy of each of the floating units (3): When the output electric energy of the new energy power generation unit is greater than the sum of the storable electric energy of all the floating units (3), the output electric energy of the new energy power generation unit to the motor (21) corresponding to each of the floating units (3) is determined as the storable electric energy of the current floating unit (3); When the output electric energy of the new energy power generation unit is not greater than the sum of the storable electric energy of all the floating units (3), the following steps are performed: dividing all the floating units (3) with the same storable electric energy into a floating unit set; determining the proportion of the total storable electric energy of each floating unit set to the total storable electric energy of all the floating unit sets; allocating the output electric energy of the new energy power generation unit to each floating unit set according to the proportion of each floating unit set; for each floating unit set, allocating the electric energy allocated to the current floating unit set to each floating unit (3) in the floating unit set in turn; wherein the floating unit (3) whose allocated electric energy is the storable electric energy is in the maximum buoyancy potential energy state, and the floating unit (3) whose allocated electric energy is less than the storable electric energy is in between the minimum buoyancy potential energy state and the maximum buoyancy potential energy state.

2. The buoyancy energy storage system according to claim 1, characterized in that: Each lifting unit (12) is provided with a limiting rail (121) arranged in a vertical direction, and each fixing assembly (32) of the floating unit (3) is provided with a limiting block (321), and the limiting block (321) can move up and down along the limiting rail (121).

3. The buoyancy energy storage system according to claim 2, characterized in that: The fixing assembly (32) of each floating unit (3) is provided with a roller (322), and the roller (322) is in contact with the limiting track (121).

4. The buoyancy energy storage system according to claim 1, characterized in that: The transmission assembly (23) comprises an electromagnetic clutch (231), a gear assembly (232) meshing with the electromagnetic clutch (231), and a transmission member (233) connected to the gear assembly (232), wherein the transmission member (233) is connected to the fixed assembly (32); During the energy storage phase, the control unit controls the motor (21) and the electromagnetic clutch (231) to connect; During the energy release phase, the control unit controls the generator (22) and the electromagnetic clutch (231) to be connected.

5. The buoyancy energy storage system according to claim 4, characterized in that: The transmission member (233) is a chain or a steel wire rope; When the transmission member (233) is a chain, the fixing assembly (32) is provided with a fixing portion (323), the fixing portion (323) is a vertically penetrating structure, and a fixing member (324) for passing through the chain is provided in the fixing portion (323), and the transmission member (233) and the fixing portion (323) are fixed by the fixing member (324).

6. The buoyancy energy storage system according to claim 1, characterized in that: The fixing assembly (32) includes a fixing shell (325), the fixing shell (325) is provided with an internal thread, the floating body (31) is provided with an external thread, and the floating body (31) and the fixing shell (325) are fixed by the thread; and / or, The upper end surface and the lower end surface of the floating body (31) are both conical surfaces; and / or, The frame (1) is a steel frame structure, and the steel frame structure is a steel frame structure that has been treated with marine anti-corrosion and anti-fouling treatment; and / or, The new energy power generation unit is a solar power generation unit, a wind power generation unit or an ocean power generation unit.

7. A buoyancy energy storage method, characterized in that: Based on the buoyancy energy storage system according to any one of claims 1 to 6, the method comprises: During the energy storage phase, the control unit controls the motor (21) to connect with the transmission assembly (23), and controls the new energy generation unit to supply power to the motor (21), so that the motor (21) drives the transmission assembly (23) to move, and drives the floating body unit (3) to move downward along the lifting unit (12) through the transmission assembly (23), thereby converting the electrical energy generated by the new energy generation unit into the buoyancy potential energy of the floating body (31); During the energy release phase, the control unit controls the connection between the generator (22) and the transmission assembly (23), and the floating body (31) with buoyancy potential energy moves upward to drive the transmission assembly (23) to move through the fixed assembly (32), thereby driving the generator (22) to generate electricity.

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