Marine comprehensive energy island power supply system based on single-line looped network and underwater caisson energy storage

Abstract

The invention provides an offshore comprehensive energy island power supply system based on single-line looped network and underwater caisson energy storage, which comprises an embedded optical fiber, the system comprises a first on-sea new energy DC / DC converter, a second on-sea new energy DC / DC converter, an (n-1) th on-sea new energy DC / DC converter, an nth on-sea new energy DC / DC converter, a first load DC / AC inverter, a second load DC / AC inverter and an (n-1) th load DC / AC inverter, wherein the first on-sea new energy DC / DC converter is in + 5G communication with a looped network power cable or a submarine power cable coaxial with a submarine power cable; the nth load DC / AC inverter, the first set of caisson energy storage, the nth set of caisson energy storage and the looped network controller. According to the invention, power supply and load power balance in the looped network is realized under the cooperation of offshore new energy DC / DC converter power generation, caisson energy storage and load inverter self-adaptive control.

Description

Technical Field

[0001] This invention belongs to the field of energy storage, specifically relating to a marine integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage. Background Technology

[0002] Currently, there is a strong push to develop deep-sea wind power, forming large-scale offshore wind power clusters. However, the instability of wind power leads to fluctuations in wind power transmission, directly impacting energy export and the development of offshore energy islands. Therefore, there is a need to further improve efficient and stable power supply and transmission measures for offshore wind power clusters. In particular, the stable, economical, and reliable energy needs of offshore energy islands and offshore oil extraction platforms are urgently required.

[0003] One of the economic advantages is that traditional wind power transmission often uses multi-core submarine cables, and the cost of construction and related materials for these cables increases with voltage levels. Furthermore, while superconducting technology is rapidly developing and its applications are becoming more widespread, the numerous lines required for traditional power supply methods pose significant challenges to the cost and maintenance of superconducting technology.

[0004] One aspect of safety is that traditional power supply uses a fixed voltage level for transmission. Due to the instability and unevenness of wind power, the transmission of wind power fluctuates. At the same time, the pressure shared by the series equipment in the system changes in real time. Therefore, considering the reliability of the system, redundancy design of the system is necessary, which increases the cost and size.

[0005] Furthermore, the current power supply for offshore oil extraction platforms is mainly generated by diesel engines or natural gas generator sets. However, this has problems such as high energy consumption, high noise, and environmental pollution. There is an urgent need to study an economical, reliable, stable, green, and stable energy alternative. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a power supply system for an integrated offshore energy island based on a single-line ring network and underwater caisson energy storage. A single power cable connects offshore renewable energy generation, an offshore working platform, and underwater caisson energy storage in series, forming a power supply system for an integrated offshore energy island that physically consists of a single-line ring network and underwater caisson energy storage. Because the offshore renewable energy generation and load within the ring network change in real time, the power supply voltage and series current within the ring network change synchronously. Therefore, the power balance between the power supply and load within the ring network is achieved through the coordinated absorption or release of power by the offshore renewable energy generation and underwater caisson energy storage, in conjunction with the adaptive control of the load inverter.

[0007] The following are the relevant definitions involved in this invention:

[0008] Marine Integrated Energy Island: A system consisting of marine new energy power generation, a single-line ring network, underwater caisson drainage energy storage, and a marine working platform;

[0009] Offshore work platforms include: seawater desalination, marine ranching, offshore oil and gas fields, big data centers, offshore hydrogen production, and offshore chemical production, serving as loads in the ring network;

[0010] Offshore new energy power generation includes: offshore wind power, wave power, offshore photovoltaic power, etc., which provide power for the ring network;

[0011] Single-line ring network: A power network that connects offshore renewable energy generation, underwater caisson drainage energy storage, and offshore working platforms in a ring through a single cable;

[0012] Submerged caisson drainage energy storage: Submerged caisson drainage energy storage is a new type of large-scale energy storage technology. Its principle is the reverse process of pumped storage. Submerged caisson drainage energy storage is anchored on the seabed around an integrated energy island at sea. During energy storage, surplus electricity from renewable energy generation is used to drain water from the caisson, absorbing surplus electricity from the ring network. During power generation, the pressure difference between the caisson and the water depth forces water into the caisson, simultaneously driving a DC turbine generator to generate power and release power to the ring network. Submerged caisson drainage energy storage plays a balancing role between power supply and load power in the ring network system.

[0013] The working principle of this invention is as follows:

[0014] Using submarine power cables with embedded optical fibers and power conductors coaxially, or submarine power cables + 5G, n offshore new energy DC / DC converters output, n platform load DC / AC inverters input, and n sets of caisson energy storage bidirectional DC / DC converters are connected in a ring through a single power cable to form a physically single-line ring network offshore integrated energy island power supply system.

[0015] By fully utilizing the controllable output of the offshore new energy DC / DC converter voltage source, and leveraging the potential energy of the caisson energy storage system based on its water volume and depth, the DC / DC input / output ports of the caisson energy storage bidirectional DC / DC converter are connected in series with the ring network to provide voltage and current to the platform loads within the ring network. The ring network controller collects and analyzes all data within the ring network in real time to obtain the ring network series current. Total platform load demand power Output power of n offshore new energy DC / DC converters Based on the power balance control strategy analysis, the ring network absorbs or releases power through the caisson energy storage bidirectional DC / DC converter to achieve power supply and load balance within the ring network.

[0016] The platform load DC / AC inverter is based on the platform load demand and the ring network series current. The platform load DC / AC inverter ensures that the input and output power of the platform load DC / AC inverter are matched through adaptive control of the input voltage.

[0017] The ring network controller or virtual power station communicates with all devices via optical fiber, forming a physically single-line ring network communication system for the integrated marine energy island. It reads data and controls the devices according to the control strategy to ensure the balance between power supply and load power within the ring network.

[0018] The loads on the offshore integrated energy island platform can include, based on their processing attributes, offshore hydrogen production, offshore chemical processing, offshore oil extraction, offshore oil refining, offshore aquaculture, and underwater data centers, etc. The power supply for the loads on the offshore integrated energy island platform is provided through the output of n platform load DC / AC inverters within the ring network.

[0019] The caisson energy storage bidirectional DC / DC converter is the part of the "underwater caisson drainage energy storage" connected to the ring network. Its principle is the reverse process of "pumped water storage". During peak wind power generation or when there is surplus power, the DC pump in the DC pump / hydro turbine DC generator integrated machine is controlled by the caisson energy storage bidirectional DC / DC converter to discharge the water in the underwater caisson to perform the energy storage process, while simultaneously drawing air into the underwater caisson. During off-peak wind power generation or when there is a power outage, the DC pump / hydro turbine DC generator integrated machine is started by the caisson energy storage bidirectional DC / DC converter. It uses the pressure difference between the underwater caisson and the water depth to drive the hydro turbine DC generator of the DC pump / hydro turbine DC generator integrated machine to generate power and release power to the ring network, which together with the new energy power generation to supply power to the marine integrated energy island.

[0020] Because the caisson is cylindrical and the inner and outer water bodies are separated, when water enters the caisson for power generation and when water is drained for energy storage, the water inside the caisson rotates in one direction along the caisson wall through a guide pipe. This generates rotational kinetic energy to drive the DC generator that rotates the water, while simultaneously ensuring the stability of the caisson structure based on the gyro principle. Since the water inside the caisson is constantly rotating during water intake or drainage, the DC generator that rotates the water, like wind power generation or flywheel energy storage, is always in a state of power generation, ensuring undisturbed power supply to the network.

[0021] When fluctuations in renewable energy generation cause the power supply within the ring network to fall below the platform's load demand, the underwater rotating DC generator, which is always generating power, can rapidly increase its output power through a caisson energy storage bidirectional DC / DC converter, based on the ring network's rapid power support strategy. This ensures a balance between power supply and load within the ring network. Since multiple underwater caisson drainage energy storage systems exist within the ring network, the rapid power support strategy requires at least one system to be in a low-flow drainage energy storage state (i.e., the DC pump operates at its minimum power limit). When the power supply within the ring network exceeds the load demand, the caisson energy storage bidirectional DC / DC converter can rapidly increase the power of the DC pump, absorbing excess power within the ring network without disrupting the water flow.

[0022] To achieve the above objectives, the present invention adopts the following technical solution:

[0023] The offshore integrated energy island power supply system based on single-line ring network and underwater caisson energy storage includes embedded optical fiber, a ring network power cable coaxial with the submarine power cable or submarine power cable + 5G communication, the first offshore new energy DC / DC converter, the second offshore new energy DC / DC converter, the (n-1)th offshore new energy DC / DC converter, the nth offshore new energy DC / DC converter, the first load DC / AC inverter, the second load DC / AC inverter, the (n-1)th load DC / AC inverter, the nth load DC / AC inverter, the first set of caisson energy storage, the nth set of caisson energy storage and the ring network controller;

[0024] The system comprises the first offshore new energy DC / DC converter, the second offshore new energy DC / DC converter, the (n-1)th offshore new energy DC / DC converter, the nth offshore new energy DC / DC converter, the first load DC / AC inverter, the second load DC / AC inverter, the (n-1)th load DC / AC inverter, the nth load DC / AC inverter, the first set of bidirectional DC / DC converters for caisson energy storage, and the nth set of bidirectional DC / DC converters for caisson energy storage. Based on geographical distribution, the positive terminal of the first offshore new energy DC / DC converter is connected to the positive terminal of the adjacent first load DC / AC inverter via a ring network power cable; the negative terminal of the first load DC / AC inverter is connected to the negative terminal of the adjacent second offshore new energy DC / DC converter; the positive terminal of the second offshore new energy DC / DC converter is connected to the positive terminal of the adjacent second load DC / AC inverter; and the negative terminal of the second load DC / AC inverter is connected to the positive terminal of the adjacent first set of bidirectional DC / DC converters for caisson energy storage. The A-terminal of the bidirectional DC / DC converter of the first set of caisson energy storage is connected; the B-terminal of the bidirectional DC / DC converter of the first set of caisson energy storage is connected to the negative terminal of the adjacent (n-1)th offshore new energy DC / DC converter; the positive terminal of the (n-1)th offshore new energy DC / DC converter is connected to the positive terminal of the adjacent (n-1)th load DC / AC inverter; the negative terminal of the (n-1)th load DC / AC inverter is connected to the negative terminal of the adjacent nth offshore new energy DC / DC converter; the positive terminal of the nth offshore new energy DC / DC converter is connected to the positive terminal of the adjacent nth load DC / AC inverter; the negative terminal of the nth load DC / AC inverter is connected to the A-terminal of the adjacent nth set of bidirectional DC / DC converters of the caisson energy storage; the B-terminal of the bidirectional DC / DC converter of the nth set of caisson energy storage is connected to the negative terminal of the adjacent first offshore new energy DC / DC converter, forming a comprehensive offshore energy island integrating offshore new energy power generation, single-line ring network, offshore working platform, and underwater caisson drainage energy storage.

[0025] Beneficial effects:

[0026] 1. Because the supply voltage within the ring network changes dynamically with the power generation of new energy sources and the optimized output voltage and current established based on constraints, system redundancy is significantly reduced, system size is decreased, and power density is increased. Since no fixed voltage or current is required within the ring network, the input and output power of offshore new energy generation combined with underwater submerged energy storage dynamically tracks load changes, ensuring a balance between supply and load power within the ring network. Traditional power grid voltages are fixed, such as 400V, 10KV, and 35KV.

[0027] 2. Since the single-line ring network structure uses a single power cable for transmission, it greatly simplifies and reduces the corresponding costs of materials, construction, and maintenance.

[0028] 3. Since the current is the same within the ring network, the load and power supply are balanced, thus the load and power supply voltage are equal. Considering factors such as line loss, the maximum withstand voltage of the equipment, and the maximum power, an optimal voltage function model is established to improve the working efficiency within the ring network.

[0029] 4. Integrate offshore new energy power generation, single-line ring network, offshore working platform, and underwater caisson energy storage to form an integrated offshore energy island.

[0030] 5. The underwater caisson drainage energy storage rapid response mechanism ensures rapid absorption and release of power within the ring network without disturbance.

[0031] 6. The input voltage of the DC / AC inverter is adaptively controlled to match the power requirements of the output load.

[0032] 7. The innovative combination of single-line ring network and underwater caisson drainage energy storage accelerates the development of integrated offshore energy islands and has strong operability.

[0033] 8. By using a bidirectional DC / DC converter for caisson energy storage, a bridge is built between underwater caisson energy storage and the ring network for energy exchange. By absorbing or releasing power, the power supply and load power in the ring network are balanced, and surplus power is stored in the caisson.

[0034] 9. The offshore new energy DC / DC converter, load DC / AC inverter, caisson energy storage bidirectional DC / DC converter and ring network controller all adopt mature technologies.

[0035] 10. Power supply and communication adopt a ring network power cable with embedded optical fiber and a single submarine power cable coaxial, which ensures the reliability and real-time performance of power supply and communication, while greatly reducing material and installation costs.

[0036] 11. The ring network controller, together with the virtual power station, controls and manages the source, grid, load, and storage within the ring network to ensure a balance between power supply and load within the ring network. Attached Figure Description

[0037] Figure 1A schematic diagram of the offshore integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage according to the present invention;

[0038] Figure 2 Schematic diagram of the marine new energy DC / DC converter of this invention;

[0039] Figure 3 Schematic diagram of the load DC / AC inverter of this invention;

[0040] Figure 4 A schematic diagram of the caisson energy storage bidirectional DC / DC converter of the present invention.

[0041] The attached diagram is labeled as follows: 1. Ring network power cable; 2. First offshore new energy DC / DC converter; 3. Second offshore new energy DC / DC converter; 4. (n-1)th offshore new energy DC / DC converter; 5. Nth offshore new energy DC / DC converter; 6. First load DC / AC inverter; 7. Second load DC / AC inverter; 8. (n-1)th load DC / AC inverter; 9. Nth load DC / AC inverter; 10. First set of caisson energy storage; 11. Nth set of caisson energy storage; 12. Ring network controller; 13. Embedded optical fiber; 14. Offshore wind and wave energy generation unit. 15. DC / DC converter; 16. DC / DC sub-controller; 17. DC / DC converter input terminal; 18. DC / DC converter positive output terminal; 19. DC / DC converter negative output terminal; 20. DC / DC converter short-circuit switch; 21. DC / AC inverter; 22. Offshore platform load; 23. DC / AC sub-controller; 24. DC positive input terminal of DC / AC inverter; 25. DC negative input terminal; 26. AC output terminal; 27. Current direction; 28. Next device of DC / AC inverter; 29. ​​Previous device of DC / AC inverter; 20. Short circuit of DC / AC inverter. 30. Switch; 31. Energy storage module; 32. Previous device of DC / DC converter; 33. Next device of DC / DC converter; 34. Underwater caisson drainage energy storage device; 35. DC pump / turbine DC generator; 36. Water-body rotating DC generator; 37. Water storage caisson; 38. Caisson energy storage sub-controller; 39. Caisson energy storage bidirectional DC / DC converter; 40. Ring network; 41. Power supply input interface; 42. Pump power output terminal; 43. B connection terminal of bidirectional input / output interface; 44. A connection terminal of bidirectional input / output interface; 45. Previous adjacent device of caisson energy storage bidirectional DC / DC converter. 46. ​​The next adjacent device of the caisson energy storage bidirectional DC / DC converter; 47. Terminal A of the first set of caisson energy storage 10 bidirectional DC / DC converter; 48. Terminal B of the first set of caisson energy storage 10 bidirectional DC / DC converter; 49. Terminal A of the nth set of caisson energy storage 11 bidirectional DC / DC converter; 50. Terminal B of the nth set of caisson energy storage 11 bidirectional DC / DC converter; 51. DC output terminal of the water body rotating DC generator; 52. Output terminal of the water turbine DC generator in the DC pump / turbine DC generator integrated machine; 53. DC power input terminal of the DC pump in the DC pump / turbine DC generator integrated machine. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0043] like Figure 1 and Figure 2 As shown, the marine integrated energy island power supply system based on single-line ring network and underwater caisson energy storage of the present invention includes an embedded optical fiber 13, which is coaxial with the ring network power cable 1 or submarine power cable + 5G communication, a first marine new energy DC / DC converter 2, a second marine new energy DC / DC converter 3, an (n-1)th marine new energy DC / DC converter 4, an nth marine new energy DC / DC converter 5, a first load DC / AC inverter 6, a second load DC / AC inverter 7, an (n-1)th load DC / AC inverter 8, an nth load DC / AC inverter 9, a first set of caisson energy storage 10, an nth set of caisson energy storage 11, and a ring network controller 12.

[0044] Among them, the first offshore new energy DC / DC converter 2, the second offshore new energy DC / DC converter 3, the (n-1)th offshore new energy DC / DC converter 4, the nth offshore new energy DC / DC converter 5, the first load DC / AC inverter 6, the second load DC / AC inverter 7, the (n-1)th load DC / AC inverter 8, the nth load DC / AC inverter 9, the bidirectional DC / DC converter of the first set of caisson energy storage 10, and the bidirectional DC / DC converter of the nth set of caisson energy storage 11. The DC converters, based on geographical distribution, are connected via a ring network power cable 1. The positive terminal of the first offshore new energy DC / DC converter 2 is connected to the positive terminal of the adjacent first load DC / AC inverter 6; the negative terminal of the first load DC / AC inverter 6 is connected to the negative terminal of the adjacent second offshore new energy DC / DC converter 3; the positive terminal of the second offshore new energy DC / DC converter 3 is connected to the positive terminal of the adjacent second load DC / AC inverter 7; and the negative terminal of the second load DC / AC inverter 7 is connected to the adjacent first set of caisson storage... The first set of caisson energy storage 10 bidirectional DC / DC converters is connected to terminal A 47; terminal B 48 of the first set of caisson energy storage 10 bidirectional DC / DC converters is connected to the negative terminal of the adjacent (n-1)th offshore new energy DC / DC converter 4; the positive terminal of the (n-1)th offshore new energy DC / DC converter 4 is connected to the positive terminal of the adjacent (n-1)th load DC / AC inverter 8; the negative terminal of the (n-1)th load DC / AC inverter 8 is connected to the negative terminal of the adjacent nth offshore new energy DC / DC converter 5; the nth offshore new energy DC / DC converter... The positive terminal of DC converter 5 is connected to the positive terminal of the adjacent nth load DC / AC inverter 9; the negative terminal of the nth load DC / AC inverter 9 is connected to the A terminal 49 of the bidirectional DC / DC converter of the adjacent nth set of caisson energy storage 11; the B terminal 50 of the bidirectional DC / DC converter of the nth set of caisson energy storage 11 is connected to the negative terminal of the adjacent first offshore new energy DC / DC converter 2, forming an integrated offshore energy island that combines offshore new energy power generation, single-line ring network, offshore working platform, and underwater caisson drainage energy storage.

[0045] The ring network controller 12 is connected via fiber optic cables embedded in power cables to the sub-controllers embedded in the first offshore new energy DC / DC converter 2, the second offshore new energy DC / DC converter 3, the (n-1)th offshore new energy DC / DC converter 4, the nth offshore new energy DC / DC converter 5, the first load DC / AC inverter 6, the second load DC / AC inverter 7, the (n-1)th load DC / AC inverter 8, the nth load DC / AC inverter 9, the bidirectional DC / DC converter of the first set of caisson energy storage 10, and the bidirectional DC / DC converter of the nth set of caisson energy storage 11, respectively, to monitor all equipment in real time.

[0046] like Figure 2 and Figure 3As shown, the first offshore new energy DC / DC converter 2, the second offshore new energy DC / DC converter 3, the (n-1)th offshore new energy DC / DC converter 4, and the nth offshore new energy DC / DC converter 5 all include an offshore wind and wave power generation unit 14, a DC / DC converter 15, and a DC / DC sub-controller 16. The input terminal 17 of the DC / DC converter has a maximum power point tracking (MPPT) function, which is connected to the output terminal of the offshore wind and wave power generation unit 14. Based on the characteristics of offshore wind power generation, the maximum power of offshore wind power generation is obtained through the MPPT function. The positive output terminal 18 and the negative output terminal 19 of the DC / DC converter are DC voltage source output terminals. Through the ring network power cable 1 and according to the current direction 27 from negative to positive, the positive output terminal 18 of the DC / DC converter is connected to the positive terminal of the next device 33 of the DC / DC converter according to the device type, such as load type. The negative output terminal 19 of the DC / DC converter is connected to the positive terminal of the previous device 32 of the DC / DC converter according to the device type, such as power supply type, and is connected to the ring network.

[0047] Among them, the equipment types are divided into power supply type and load type. The DC / DC converter 15 is the power supply end and is of the power supply type. The positive output terminal 18 and the negative output terminal 19 of the DC / DC converter are connected in series in the ring network from negative to positive according to the current direction 27 in the ring network through the ring network power cable 1.

[0048] The DC / AC inverter 21 is a load-type absorber of ring network energy. Its positive DC input terminal 24 and negative DC input terminal 25 are connected in series in the ring network via the ring network power cable 1, following the current direction 27 within the ring network from negative to positive. That is, the input voltage between the positive DC input terminal 24 and the negative DC input terminal 25 of the DC / AC inverter is negative.

[0049] Under the control of the DC / DC sub-controller 16, the DC / DC converter 15 is based on the output power of the offshore wind and wave power generation unit 14 and the ring network series current obtained according to the mathematical model algorithm. By adjusting the voltage between the positive output terminal 18 and the negative output terminal 19 of the DC / DC converter Control the offshore new energy DC / DC converter to provide power to the ring network.

[0050] A short-circuit switch 20 is installed between the positive output terminal 18 and the negative output terminal 19 of the DC / DC converter. When the input reaches the lower power limit... In the event of a fault, short-circuit switch 20 will short-circuit the positive output terminal 18 of the DC / DC converter with the negative output terminal 19 of the DC / DC converter. To ensure smooth connection of the ring network, the DC / DC sub-controller 16 monitors all sensor data of the offshore new energy DC / DC converter in real time and maintains communication with the ring network controller 12 via fiber optic cable 13. The DC / DC sub-controller 16 analyzes the collected data and the data obtained from the ring network controller 12, and controls the offshore new energy DC / DC converter in real time according to the control strategy of the offshore new energy DC / DC converter. The data is uploaded to the ring network controller 12. Within the ring network, the first offshore new energy DC / DC converter 2, the second offshore new energy DC / DC converter 3, the (n-1)th offshore new energy DC / DC converter 4, and the nth offshore new energy DC / DC converter 5 are connected in series according to the offshore wind power distribution. These converters supply power to the offshore working platform load through the first load DC / AC inverter 6, the second load DC / AC inverter 7, the (n-1)th load DC / AC inverter 8, and the nth load DC / AC inverter 9.

[0051] like Figure 3 As shown, the first load DC / AC inverter 6, the second load DC / AC inverter 7, the (n-1)th load DC / AC inverter 8, and the nth load DC / AC inverter 9 all include a DC / AC inverter 21, an offshore platform load 22, a DC / AC sub-controller 23, and an AC output terminal 26; wherein the DC positive input terminal 24 and the DC negative input terminal 25 of the DC / AC inverter have input voltages. The adjustment function is similar to the voltage regulation function of maximum power point tracking (MPPT); the DC / AC sub-controller 23 adjusts the power based on the offshore platform load 22. With DC / AC inverter 21 efficiency The ratio is equal to the power at the negative input of DC. and the series current of the ring network Determine the voltage between the positive DC input terminal 24 and the negative DC input terminal 25 of the DC / AC inverter. The DC power within the ring network 40 is converted into AC power via DC / AC inverter 21 through DC / AC inverter 21, and then supplied to the offshore platform load 22 via AC output terminal 26. .

[0052] The offshore platform includes functions such as offshore hydrogen production, offshore chemical industry, offshore oil extraction, offshore oil production, and offshore aquaculture. It is powered by n load DC / AC inverters within the ring network.

[0053] The DC positive input terminal 24 and the DC negative input terminal 25 of the DC / AC inverter are connected in series through the ring network power cable 1 in opposite directions from negative to positive according to the current direction 27. That is, the voltage at the DC input terminal of the DC / AC inverter... The voltage is negative, so the positive DC input terminal 24 and the negative DC input terminal 25 of the DC / AC inverter are connected to the ring network. Based on the offshore platform load of 22 power With DC / AC inverter 21 efficiency The ratio is equal to the power at the negative input of the DC circuit. Series current with ring network Under the control of the DC / AC sub-controller 23, the voltage between the positive DC input terminal 24 and the negative DC input terminal 25 of the DC / AC inverter is regulated. To obtain optimal power input and ensure the power supply for the offshore platform load 22.

[0054] The DC positive input terminal 24 and the DC negative input terminal 25 of the DC / AC inverter are connected in series from negative to positive in opposite directions according to the current direction 27 via the ring network power cable 1. Depending on the equipment type, if the next device 28 of the DC / AC inverter is a power supply type device of the offshore new energy DC / DC converter, the DC negative input terminal 25 of the DC / AC inverter is connected to the negative terminal of the offshore new energy DC / DC converter; if the next device 28 of the DC / AC inverter is a load type device of the DC / AC inverter, the DC negative input terminal 25 of the DC / AC inverter is connected to the positive terminal of the DC / AC inverter of one device 28.

[0055] The DC positive input terminal 24 of the DC / AC inverter is also connected via the ring network power cable 1 in the opposite direction from negative to positive according to the current direction 27. If the upstream device 29 of the DC / AC inverter is a power supply type device of the offshore new energy DC / DC converter, the DC positive input terminal 24 of the DC / AC inverter is connected to the positive terminal of the offshore new energy DC / DC converter; if the upstream device 29 of the DC / AC inverter is a load type device of the DC / AC inverter, the DC positive input terminal 24 of the DC / AC inverter is connected to the negative terminal of the DC / AC inverter of the upstream device 29.

[0056] Considering the fluctuations in offshore wind power generation and load, an energy storage module 31 is installed between the DC positive input terminal 24 and the DC negative input terminal 25 of the DC / AC inverter. The energy storage module 31's ability to absorb or release power helps to mitigate the input voltage fluctuations. Rapid changes.

[0057] Considering the load power Zero or fault, i.e. When short-circuiting the input terminal, the ring network is ensured to be connected smoothly. Similarly, a short-circuit switch 30 is installed between the DC positive input terminal 24 and the DC negative input terminal 25 of the DC / AC inverter.

[0058] The DC / AC sub-controller 23 monitors the load DC / AC inverter 21 in real time and maintains communication with the ring network controller 12 via fiber optic cable 13. Based on the collected data and data analysis obtained from the ring network controller 12, the DC / AC sub-controller 23 controls the load DC / AC inverter 21 in real time according to the load DC / AC inverter control strategy, and uploads the data to the ring network controller 12. The loads within the ring network 40 are connected in series via the first load DC / AC inverter 6, the second load DC / AC inverter 7, the (n-1)th load DC / AC inverter 8, and the nth load DC / AC inverter 9, converting DC power into AC power to provide electricity to the offshore platform load 22.

[0059] like Figure 4 As shown, the caisson energy storage bidirectional DC / DC converter 39 is a device connecting the underwater caisson drainage energy storage device 34 to the ring network 40, and exchanges energy with the ring network 40. The caisson energy storage bidirectional DC / DC converter 39 includes: a bidirectional input / output interface A connection terminal 44 and a bidirectional input / output interface B connection terminal 43, a power supply input interface 41, and a water pump power output terminal 42. The A connection terminal 44 of the bidirectional input / output interface of the caisson energy storage bidirectional DC / DC converter 39 is connected in series with one end of an adjacent device 45 of the caisson energy storage bidirectional DC / DC converter in the ring network via the ring network power cable 1; the B connection terminal 43 of the bidirectional input / output interface is connected in series with one end of the next adjacent device 46 of the caisson energy storage bidirectional DC / DC converter in the ring network 40 via the ring network power cable 1; thus, the caisson energy storage bidirectional DC / DC converter 39 absorbs or releases power to the ring network 40 through the A connection terminal 44 and the B connection terminal 43 of the bidirectional input / output interface. That is, when absorbing power, the input voltage of the A connection terminal 44 and the B connection terminal 43 of the bidirectional input / output interface of the caisson energy storage bidirectional DC / DC converter 39 is negative; when releasing power, the output voltage of the A connection terminal 44 and the B connection terminal 43 of the bidirectional input / output interface of the caisson energy storage bidirectional DC / DC converter 39 is positive.

[0060] Among them, the underwater caisson drainage energy storage device 34 is anchored on the seabed of the integrated energy island at sea, and includes: water storage caisson 37, DC water pump / water turbine DC generator integrated machine 35, water body rotating DC generator 36, caisson energy storage bidirectional DC / DC converter 39 and caisson energy storage sub-controller 38.

[0061] The water storage caisson 37 is a sealed cylindrical structure, vertically anchored to the seabed of the integrated energy island at sea. An impeller mechanism is coaxially mounted inside the caisson 37, driving a water-based rotary DC generator 36 to generate electricity. The DC output terminal 51 of the water-based rotary DC generator is connected to the power input interface 41 of the caisson energy storage bidirectional DC / DC converter 39. Simultaneously, the power input interface 41 is connected to the output terminal 52 of the turbine DC generator in the integrated DC pump / turbine generator 35. The DC power generated by the water-based rotary DC generator 36 and the turbine DC generator in the integrated DC pump / turbine generator 35 is transmitted to the ring network 40 via the A connection terminal 43 and the B connection terminal 44 of the bidirectional input / output interface of the caisson energy storage bidirectional DC / DC converter, providing power support for the ring network 40.

[0062] The DC pump power input terminal 53 of the DC pump / hydro turbine DC generator is connected to the pump power output terminal 42 of the caisson energy storage bidirectional DC / DC converter 39. Under the control of the caisson energy storage sub-controller 38, according to the caisson energy storage strategy, the excess power of the ring network 40 is absorbed through the A connection terminal 43 and the B connection terminal 44 of the bidirectional input / output interface of the caisson energy storage bidirectional DC / DC converter 39, so as to achieve load and power supply balance.

[0063] The integrated DC pump / hydro turbine DC generator 35 is installed at the bottom of the water storage caisson 37. The water storage caisson 37 is the carrier of energy storage capacity, and its energy storage capacity is related to the potential energy of the water depth and its internal volume. The deeper the water, the greater the potential energy, and the larger the volume, the greater the water volume it can hold, thus resulting in a larger energy storage capacity. By utilizing the large linearly adjustable power range of the DC pump and hydro turbine DC generator in the water-rotating DC generator 36 and the integrated DC pump / hydro turbine DC generator 35, the continuity of power absorption or release from the bidirectional DC / DC converter 39 of the caisson energy storage to the ring network 40 is ensured, reducing the power fluctuation of the ring network 40.

[0064] Among them, the principle of the underwater caisson drainage energy storage device 34 is the reverse process of "pumped water storage". When the sum of the power generation of the first offshore new energy DC / DC converter 2, the second offshore new energy DC / DC converter 3, the (n-1)th offshore new energy DC / DC converter 4, and the nth offshore new energy DC / DC converter 5 within the ring network 40 The power demand is greater than the sum of the power requirements of the first load DC / AC inverter (6), the second load DC / AC inverter (7), the (n-1)th load DC / AC inverter (8), and the nth load DC / AC inverter (9). ,Right now Excess power is generated. At this time, the caisson energy storage sub-controller 38, based on the data provided by the ring network controller 12, uses the A connection terminal 43 and the B connection terminal 44 of the bidirectional input / output interface of the caisson energy storage bidirectional DC / DC converter 39 to control the DC water pump in the DC water pump / hydro turbine DC generator integrated machine 35 to discharge the water in the water storage caisson 37, absorb the excess power in the ring network 40 to perform the energy storage process, and at the same time draw the atmosphere into the water storage caisson 37.

[0065] When the offshore wind and wave power generation unit 14 is in a low power generation period or when there is a power outage, the caisson energy storage sub-controller 38 controls the turbine DC generator in the DC pump / turbine DC generator integrated machine 35 according to the data provided by the ring network controller 12. It uses the pressure difference between the water storage caisson 37 and the water depth to force water into the water storage caisson 37, and at the same time drives the turbine DC generator in the DC pump / turbine DC generator integrated machine 35 to do work and generate electricity. The electricity is supplied to the offshore integrated energy island through the ring network 40 via the caisson energy storage bidirectional DC / DC converter 39.

[0066] Because the water storage caisson 37 has a cylindrical structure, separating the inner and outer water bodies, when water is introduced into the caisson 37 for power generation and when water is discharged for energy storage, the water flow is through the guide pipes installed along the inner wall of the caisson 37. This controls the water body inside the caisson 37 to rotate in one direction. On the one hand, this generates rotational kinetic energy to drive the DC generator 36 to generate electricity; on the other hand, it ensures the structural stability of the caisson 37 based on the principle of gyroscopes. Since the kinetic energy of the water in the caisson 37 during the water intake or drainage process always keeps the water body inside the caisson 37 rotating in one direction, the DC generator 36, like wind power generation or flywheel energy storage, is always in a power generation state. The purpose is to quickly balance and suppress short-term fluctuations in power supply and load power within the ring network. When one or more offshore wind or wave power generation units 14 generate electricity or the offshore platform load 22 experiences short-term fluctuations, causing a change in the power balance between the power supply and load within the ring network 40, the ring network controller 12 controls the water-based rotating DC generator 36 to rapidly increase or decrease its output power through one or more sets of caisson energy storage sub-controllers 38, and releases power to the ring network 40 rapidly and without disturbance through the caisson energy storage bidirectional DC / DC converter 39 via bidirectional input / output interface A connection terminal 43 and B connection terminal 44, ensuring the stability of the power balance between the power supply and load within the ring network 40.

[0067] Since there are multiple underwater caisson drainage energy storage devices 34 in the ring network 40, when the power supply and load power in the ring network 40 are in a stable balance, under the requirements of the ring network's rapid power support strategy, there is always one underwater caisson drainage energy storage device 34 in a low-flow drainage energy storage state. That is, the DC pump in the DC pump / hydro turbine DC generator integrated machine 35 operates at the minimum limit power to avoid consuming power supply. When the power supply within the ring network 40 exceeds the load demand trend, and it is impossible to quickly reduce the output power of the water-rotating DC generator 36 to balance the load demand through one or more sets of caisson energy storage sub-controllers 38, the ring network controller 12 controls the caisson energy storage bidirectional DC / DC converter 39 through one or more sets of caisson energy storage sub-controllers 38 via the A connection terminal 43 and the B connection terminal 44 of the bidirectional input / output interface to obtain the excess power in the ring network that exceeds the load demand without disturbance. After being converted by the caisson energy storage bidirectional DC / DC converter 39, it is transmitted through the DC water pump power input terminal 53 in the DC water pump / water turbine DC generator integrated machine to quickly increase the power of the DC water pump and increase the water flow to quickly absorb the excess power within the ring network 40.

[0068] In each set of caisson energy storage bidirectional DC / DC converters 39, the input and output power through the A connection terminal 43 and the B connection terminal 44 of the bidirectional input and output interface is the sum of the power generated by the water-rotating DC generator 36 and the integrated DC pump / turbine DC generator 35. The output power is: the output power of the turbine DC generator + the water-rotating DC generator is positive, releasing power into the ring network 40; the input power is: the water-rotating DC generator - the power demanded by the DC pump. When the power demanded by the DC pump is greater than that of the water-rotating DC generator, the input and output power through the A connection terminal 43 and the B connection terminal 44 of the bidirectional input and output interface is negative, absorbing power into the ring network 40.

[0069] In summary, in the offshore integrated energy island power supply system with single-line ring network and underwater caisson energy storage, based on the ring network balance control strategy, the ring network controller monitors and coordinates the control of n offshore new energy DC / DC converters, n load DC / AC inverters, and n sets of caisson energy storage at 12 o'clock to achieve disturbance-free balance and optimal matching between power supply and load power, and maximize the utilization of new energy.

[0070] Considering the relationship between the pressure bearing capacity, stability, economy and energy storage capacity configuration of the caisson structure, multiple sets of "underwater caisson drainage energy storage" configurations should be adopted in a certain scale of marine integrated energy island ring network.

Claims

1. A marine integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage, characterized in that, Includes embedded optical fiber, a ring network power cable coaxial with the submarine power cable or submarine power cable + 5G communication, the first marine new energy DC / DC converter, the second marine new energy DC / DC converter, the (n-1)th marine new energy DC / DC converter, the nth marine new energy DC / DC converter, the first load DC / AC inverter, the second load DC / AC inverter, the (n-1)th load DC / AC inverter, the nth load DC / AC inverter, the first set of caisson energy storage, the nth set of caisson energy storage and the ring network controller; The system comprises the first offshore new energy DC / DC converter, the second offshore new energy DC / DC converter, the (n-1)th offshore new energy DC / DC converter, the nth offshore new energy DC / DC converter, the first load DC / AC inverter, the second load DC / AC inverter, the (n-1)th load DC / AC inverter, the nth load DC / AC inverter, the first set of bidirectional DC / DC converters for caisson energy storage, and the nth set of bidirectional DC / DC converters for caisson energy storage. Based on geographical distribution, the positive terminal of the first offshore new energy DC / DC converter is connected to the positive terminal of the adjacent first load DC / AC inverter via a ring network power cable; the negative terminal of the first load DC / AC inverter is connected to the negative terminal of the adjacent second offshore new energy DC / DC converter; the positive terminal of the second offshore new energy DC / DC converter is connected to the positive terminal of the adjacent second load DC / AC inverter; and the negative terminal of the second load DC / AC inverter is connected to the positive terminal of the adjacent first set of bidirectional DC / DC converters for caisson energy storage. The A-terminal of the bidirectional DC / DC converter of the first set of caisson energy storage is connected; the B-terminal of the bidirectional DC / DC converter of the first set of caisson energy storage is connected to the negative terminal of the adjacent (n-1)th offshore new energy DC / DC converter; the positive terminal of the (n-1)th offshore new energy DC / DC converter is connected to the positive terminal of the adjacent (n-1)th load DC / AC inverter; the negative terminal of the (n-1)th load DC / AC inverter is connected to the negative terminal of the adjacent nth offshore new energy DC / DC converter; the positive terminal of the nth offshore new energy DC / DC converter is connected to the positive terminal of the adjacent nth load DC / AC inverter; the negative terminal of the nth load DC / AC inverter is connected to the A-terminal of the adjacent nth set of bidirectional DC / DC converters of the caisson energy storage; the B-terminal of the bidirectional DC / DC converter of the nth set of caisson energy storage is connected to the negative terminal of the adjacent first offshore new energy DC / DC converter, forming a comprehensive offshore energy island integrating offshore new energy power generation, single-line ring network, offshore working platform, and underwater caisson drainage energy storage.

2. The offshore integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage as described in claim 1, characterized in that, The ring network controller is connected via fiber optic cables embedded in the power cables to the sub-controllers embedded in the first, second, n-1, and nth offshore new energy DC / DC converters, the first, second, n-1, and nth load DC / AC inverters, the first, second, n-1, and nth load DC / AC inverters, the first set of bidirectional DC / DC converters for caisson energy storage, and the nth set of bidirectional DC / DC converters for caisson energy storage, thereby monitoring all equipment in real time.

3. The offshore integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage as described in claim 1, characterized in that, The first, second, (n-1), and nth offshore new energy DC / DC converters all include offshore wind and wave power generation units, DC / DC converters, and DC / DC sub-controllers. The DC / DC converter input has a maximum power point tracking (MPPT) function, connected to the output of the offshore wind and wave power generation unit. Based on the characteristics of offshore wind power generation, the maximum power of offshore wind power generation is obtained through the MPPT function. The positive and negative outputs of the DC / DC converter are DC voltage source outputs. Through a ring network power cable and following the current direction from negative to positive, the positive output of the DC / DC converter is connected to the positive terminal of the next device in the ring network, depending on the device type (e.g., load type), while the negative output is connected to the positive terminal of the previous device in the ring network, depending on the device type (e.g., power supply type).

4. The offshore integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage as described in claim 1, characterized in that, The equipment types are divided into power supply type and load type. The DC / DC converter is a power supply type, and its positive and negative output terminals are connected in series in the ring network through a ring network power cable, in the same direction from negative to positive according to the current direction in the ring network. The DC / AC inverter is a load type that absorbs energy from the ring network. Its DC positive and DC negative input terminals are connected in series in the ring network through a ring network power cable, in the opposite direction from negative to positive according to the current direction in the ring network.

5. The offshore integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage as described in claim 1, characterized in that, Under the control of the DC / DC sub-controller, the DC / DC converter operates based on the output power of the offshore wind and wave power generation units and the ring network series current obtained from a mathematical model algorithm. By adjusting the voltage between the positive output terminal and the negative output terminal of the DC / DC converter Control the offshore new energy DC / DC converter to provide power to the ring network; A short-circuit switch is installed between the positive and negative output terminals of the DC / DC converter. When the input reaches the lower power limit... In the event of a fault, the short-circuit switch trips, short-circuiting the positive output terminal of the DC / DC converter to the negative output terminal. To ensure smooth connection of the ring network, the DC / DC sub-controller monitors all sensor data of the offshore new energy DC / DC converter in real time and maintains communication with the ring network controller via optical fiber. The DC / DC sub-controller analyzes the data collected from the ring network controller and controls the offshore new energy DC / DC converter in real time according to the control strategy of the offshore new energy DC / DC converter. The data is then uploaded to the ring network controller. Within the ring network, the first, second, n-1, and nth offshore new energy DC / DC converters, connected in series according to the offshore wind power distribution, supply power to the offshore working platform load through the first, second, n-1, and nth load DC / AC inverters.

6. The offshore integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage as described in claim 1, characterized in that, The first load DC / AC inverter, the second load DC / AC inverter, the (n-1)th load DC / AC inverter, and the nth load DC / AC inverter all include a DC / AC inverter, an offshore platform load, a DC / AC sub-controller, and an AC output terminal; wherein, the positive DC input terminal and the negative DC input terminal of the DC / AC inverter have input voltages. Adjustment function; DC / AC sub-controller adjusts power based on offshore platform load. DC / AC inverter efficiency The ratio is equal to the power at the negative input of DC. and the series current of the ring network Determine the voltage between the positive DC input terminal and the negative DC input terminal of the DC / AC inverter. The DC power within the ring network is converted into AC power via the DC positive input terminal and the DC negative input terminal of the DC / AC inverter, and then supplied to the offshore platform load through the AC output terminal. .

7. The offshore integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage as described in claim 1, characterized in that, The positive DC input terminal and the negative DC input terminal of the DC / AC inverter are connected in series through a ring network power cable in opposite directions (from negative to positive) according to the current direction. This means the voltage across the DC input terminal of the DC / AC inverter... The voltage is negative, connecting the positive DC input terminal and the negative DC input terminal of the DC / AC inverter to the ring network; the voltage between the positive DC input terminal and the negative DC input terminal of the DC / AC inverter. Based on the load power of the offshore platform DC / AC inverter efficiency The ratio is equal to the power at the negative input of the DC circuit. Series current with ring network Under the control of the DC / AC sub-controller, the voltage between the positive DC input terminal and the negative DC input terminal of the DC / AC inverter is adjusted. To obtain optimal power input and ensure power supply for offshore platform loads.

8. The offshore integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage as described in claim 1, characterized in that, The positive DC input terminal and the negative DC input terminal of the DC / AC inverter are connected in series through a ring network power cable in the opposite direction of the current from negative to positive. Depending on the equipment type, such as the DC / AC inverter, the next equipment is the marine new energy DC / DC converter power supply equipment, and the negative DC input terminal of the DC / AC inverter is connected to the negative terminal of the marine new energy DC / DC converter. Furthermore, the positive DC input terminal of the DC / AC inverter is connected via a ring network power cable in the opposite direction of the current, from negative to positive. For example, if the upstream device of the DC / AC inverter is a power supply type device of a marine new energy DC / DC converter, the positive DC input terminal of the DC / AC inverter is connected to the positive terminal of the marine new energy DC / DC converter; if the upstream device of the DC / AC inverter is a load type device of a DC / AC inverter, the positive DC input terminal of the DC / AC inverter is connected to the negative terminal of the DC / AC inverter of the upstream device. Considering the fluctuations in offshore wind power generation and load, an energy storage module is installed between the positive DC input terminal and the negative DC input terminal of the DC / AC inverter. This utilizes the energy storage module's ability to absorb or release power, thus mitigating the input voltage fluctuations. Rapid changes; Considering the load power Zero or fault, i.e. When short-circuiting the input terminal, ensure a smooth connection of the ring network. Similarly, a short-circuit switch is installed between the positive DC input terminal and the negative DC input terminal of the DC / AC inverter.

9. The offshore integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage as described in claim 1, characterized in that, The DC / AC sub-controller monitors the load DC / AC inverters in real time and maintains communication with the ring network controller via fiber optic cable. Based on the collected data and data analysis obtained from the ring network controller, the DC / AC sub-controller controls the load DC / AC inverters in real time according to the load DC / AC inverter control strategy, and uploads the data to the ring network controller. The loads within the ring network are connected in series by the first load DC / AC inverter 6, the second load DC / AC inverter, the (n-1)th load DC / AC inverter, and the nth load DC / AC inverter, which converts DC power into AC power to provide electricity for the offshore platform loads.

10. The offshore integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage as described in claim 1, characterized in that, The aforementioned caisson energy storage bidirectional DC / DC converter is an underwater caisson drainage energy storage and ring network connection device, exchanging energy with the ring network. The caisson energy storage bidirectional DC / DC converter includes an A-terminal and a B-terminal bidirectional input / output interface, a power input interface, and a water pump power output terminal. The A-terminal of the bidirectional input / output interface of the caisson energy storage bidirectional DC / DC converter is connected in series with one end of an adjacent device on the caisson energy storage bidirectional DC / DC converter within the ring network via a ring network power cable. The B-terminal of the bidirectional input / output interface is connected to the ring network via a ring network power cable. The caisson energy storage bidirectional DC / DC converter is connected in series with one end of the next adjacent device. Thus, the caisson energy storage bidirectional DC / DC converter absorbs or releases power to the ring network through the A and B connections of the bidirectional input / output interface. That is, when absorbing power, the input voltage of the A and B connections of the bidirectional input / output interface of the caisson energy storage bidirectional DC / DC converter is negative; when releasing power, the output voltage of the A and B connections of the bidirectional input / output interface of the caisson energy storage bidirectional DC / DC converter is positive.

11. The offshore integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage as described in claim 1, characterized in that, The underwater caisson drainage energy storage is anchored on the seabed of the integrated energy island at sea, and includes: a water storage caisson, a DC water pump / hydro turbine DC generator, a water-body rotating DC generator, a caisson energy storage bidirectional DC / DC converter, and a caisson energy storage sub-controller; The water storage caisson is a sealed cylindrical structure, vertically anchored to the seabed of the integrated energy island at sea. An impeller mechanism is coaxially installed inside the caisson to drive a water-based rotary DC generator to generate electricity. The DC output terminal of the water-based rotary DC generator is connected to the power input interface of the caisson's bidirectional DC / DC converter, and the power input interface is also connected to the output terminal of the turbine DC generator in the integrated DC pump / turbine generator. The DC power generated by the water-based rotary DC generator and the turbine DC generator in the integrated DC pump / turbine generator is transmitted to the ring network through the A and B connection terminals of the bidirectional input / output interface of the caisson's bidirectional DC / DC converter to support the ring network power. The DC pump power input terminal of the DC pump / hydro turbine DC generator is connected to the pump power output terminal of the caisson energy storage bidirectional DC / DC converter. Under the control of the caisson energy storage sub-controller, according to the caisson energy storage strategy, the excess power of the ring network is absorbed through the A connection terminal and the B connection terminal of the bidirectional input / output interface of the caisson energy storage bidirectional DC / DC converter, so as to achieve load and power supply balance.

12. The offshore integrated energy island power supply system based on a single-line ring network and underwater caisson energy storage as described in claim 1, characterized in that, The DC pump / hydro turbine DC generator integrated unit is installed at the bottom of the water storage caisson. The water storage caisson is the carrier of energy storage capacity. Its energy storage capacity is related to the potential energy of the water depth and the internal volume. The deeper the water, the greater the potential energy and the larger the volume, the greater the water volume it can carry, and thus the greater the energy storage capacity. By utilizing the characteristics of the DC pump and hydro turbine DC generator in the water-rotating DC generator integrated unit, which have a large linearly adjustable power range, the continuity of the bidirectional DC / DC converter of the caisson energy storage for the absorption or release of power to the ring network is ensured, and the fluctuation of the ring network power is reduced. The sum of the power generation of the first, second, (n-1)th, and nth offshore renewable energy DC / DC converters within the ring network The power demand is greater than the sum of the power demands of the first load DC / AC inverter, the second load DC / AC inverter, the (n-1)th load DC / AC inverter, and the nth load DC / AC inverter. ,Right now When excess power is generated, the sub-controller of the caisson energy storage, based on the data provided by the ring network controller, uses the A connection terminal and the B connection terminal of the bidirectional input / output interface of the bidirectional DC / DC converter of the caisson energy storage to control the DC water pump in the DC water pump / hydro turbine DC generator integrated machine to discharge the water in the caisson storage tank, absorb the excess power in the ring network to perform the energy storage process, and at the same time draw the atmosphere into the caisson storage tank. When the offshore wind and wave power generation units are in a low-power period or when there is a power outage, the caisson energy storage sub-controller controls the turbine DC generator in the DC pump / turbine DC generator integrated unit based on the data provided by the ring network controller. It uses the pressure difference between the water storage caisson and the water depth to force water into the water storage caisson, and at the same time drives the turbine DC generator in the DC pump / turbine DC generator integrated unit to do work and generate electricity. The electricity is then supplied to the offshore integrated energy island through the ring network via the caisson energy storage bidirectional DC / DC converter. When one or more offshore wind or wave power generation units generate electricity or the load of the offshore platform experiences short-term fluctuations, causing a change in the power balance between the power supply and load within the ring network, the ring network controller, based on the ring network's rapid support power control strategy, controls the water-based rotating DC generator to rapidly increase or decrease its output power through one or more sets of caisson energy storage sub-controllers. It also rapidly and seamlessly increases or decreases the power output of the caisson energy storage bidirectional DC / DC converter through bidirectional input / output interfaces A and B, ensuring a stable power balance between the power supply and load within the ring network. Specifically, the input and output power of each set of caisson energy storage bidirectional DC / DC converters through the A and B connections of the bidirectional input / output interface is the sum of the power generated by the water-rotating DC generator and the integrated DC pump / turbine DC generator. The output power is: the output power of the turbine DC generator + the water-rotating DC generator is positive, releasing power into the ring network; the input power is: the water-rotating DC generator - the power demanded by the DC pump. When the power demanded by the DC pump is greater than that of the water-rotating DC generator, the input and output power of the A and B connections of the bidirectional input / output interface is negative, absorbing power into the ring network.

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