Energy storage array grid-connected converter topology, method, device, equipment, medium and product

Abstract

The invention relates to the technical field of grid connection, in particular to an energy storage array grid-connected converter topology, method, device and equipment, a medium and a product. The choppers are in one-to-one correspondence with the superconducting energy storage modules, and the input end of each chopper is electrically connected with the output end of the corresponding superconducting energy storage module; the output end of each chopper is electrically connected with the input end of the inverter; the common bus is connected with the inverter and is used for collecting the electric energy of all the superconducting energy storage modules; the technical problems of limited power capacity expansion, low reliability and lack of multi-module control can be solved.

Description

Technical Field

[0001] This invention relates to the field of grid-connected power conversion topology for energy storage arrays, and particularly to a grid-connected power conversion topology, method, apparatus, equipment, medium, and product for energy storage arrays. Background Technology

[0002] The large-scale grid connection of renewable energy sources has led to frequent problems such as grid voltage dips, harmonic interference, and active power imbalances, necessitating efficient energy storage technologies to ensure grid stability. Superconducting energy storage is one such technology for addressing the stability issues of renewable energy grid connection.

[0003] The grid-connected converter design schemes for related superconducting energy storage systems mainly fall into two categories: one employs a topology of a single superconducting energy storage magnet and a modular converter, suitable for low-power, low-capacity scenarios; the other achieves power expansion by increasing the current-carrying capacity and volume of a single superconducting magnet, assuming uniform magnet conditions and charging / discharging according to a fixed power distribution mode. However, these technologies do not consider the control challenges caused by differences in the energy storage capacity of multiple modules. This field suffers from technical problems such as limited power expansion, low reliability, and lack of multi-module control. Summary of the Invention

[0004] This invention provides a grid-connected converter topology, method, device, equipment, medium, and product for energy storage arrays, solving the technical problems of limited power expansion, low reliability, and lack of multi-module control.

[0005] In a first aspect, the present invention provides a grid-connected converter topology for an energy storage array, comprising: at least two superconducting energy storage modules; choppers corresponding one-to-one with the superconducting energy storage modules, wherein the input terminal of each chopper is electrically connected to the output terminal of the corresponding superconducting energy storage module; an inverter, wherein the output terminal of each chopper is electrically connected to the input terminal of the inverter; and a common bus connected to the inverter for collecting the electrical energy of all the superconducting energy storage modules.

[0006] In some embodiments, the common bus is a common AC bus, and the output of the inverter is connected to the common AC bus.

[0007] In some embodiments, the common bus is a common DC bus, and the output of each chopper is electrically connected to the input of the inverter.

[0008] Secondly, the present invention provides a grid-connected control method for a grid-connected converter topology of an energy storage array based on any of the above aspects, comprising: step S01, determining the number of superconducting energy storage modules to be activated according to the power demand of the grid; step S02, determining the cooperative control mode of the topology according to the status of the common bus and / or preset instructions; and step S03, performing three-loop control on the superconducting energy storage modules to be activated in the topology based on the cooperative control mode.

[0009] In some embodiments, the cooperative control mode includes: charging mode, discharging mode, and standby mode; the preset instructions include charging commands and discharging commands issued by the upper-level system; if a charging command is received from the upper-level system or the common bus voltage is higher than the charging threshold, the system enters charging mode; if a discharging command is received from the upper-level system or the common bus voltage is lower than the discharging threshold, the system enters discharging mode; after charging is completed, if no discharging command is received or no bus voltage is detected to be lower than the threshold, the system enters standby mode.

[0010] In some embodiments, step S03, which is a step of performing three-loop control on the superconducting energy storage modules that need to be started in the topology based on the cooperative control mode, includes: step S31, outputting a voltage reference value according to the energy stored in the module through the energy loop; step S32, outputting a current reference value by tracking the voltage reference value through the voltage loop; and step S33, controlling the inverter to output active current and reactive current by tracking the current reference value through the current loop.

[0011] Thirdly, the present invention provides a grid-connected control device for a grid-connected converter topology of an energy storage array based on any of the above aspects, comprising: a quantity confirmation module, used to determine the number of superconducting energy storage modules to be activated according to the power demand of the power grid; a mode selection module, used to determine the cooperative control mode of the topology according to the status of the common bus and / or preset instructions; and a three-loop control module, used to perform three-loop control on the superconducting energy storage modules to be activated in the topology based on the cooperative control mode.

[0012] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the method of any of the above aspects.

[0013] Fifthly, the present invention provides an electronic device including a processor and a memory, wherein a computer program is stored in the memory, and the processor executes the computer program to implement the method of any of the above aspects.

[0014] In a sixth aspect, the present invention provides a computer program product, including a computer program that, when executed by a processor, implements a method for any of the above aspects.

[0015] This invention provides a grid-connected converter topology, method, apparatus, equipment, medium, and product for an energy storage array. The topology includes: at least two superconducting energy storage modules; choppers corresponding one-to-one with each superconducting energy storage module, with the input terminal of each chopper electrically connected to the output terminal of the corresponding superconducting energy storage module; an inverter, with the output terminal of each chopper electrically connected to the input terminal of the inverter; and a common bus connected to the inverter for collecting the electrical energy from all superconducting energy storage modules. This invention addresses the technical problems of limited power expansion, low reliability, and lack of multi-module control. Attached Figure Description

[0016] The invention will now be described in more detail with reference to embodiments and the accompanying drawings: Figure 1 A schematic diagram of an AC aggregation topology for an energy storage array grid-connected converter topology provided in an embodiment of the present invention; Figure 2 A schematic diagram of a DC aggregation topology for an energy storage array grid-connected converter topology provided in an embodiment of the present invention; Figure 3 This is a schematic flowchart of a grid-connected control method for an energy storage array grid-connected converter topology provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the grid-connected control device for an energy storage array grid-connected converter topology provided in an embodiment of the present invention; Figure 5 This is a schematic flowchart of a charging mode control method provided in an embodiment of the present invention; Figure 6 This is a schematic flowchart of a discharge mode control method provided in an embodiment of the present invention; Figure 7 This is a schematic flowchart of a standby mode control method provided in an embodiment of the present invention.

[0017] In the accompanying drawings, the same parts are referred to by the same reference numerals, and the drawings are not drawn to scale. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention and to fully understand and implement the process of how the present invention uses technical means to solve technical problems and achieve corresponding technical effects, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The embodiments of the present invention and the various features therein can be combined with each other without conflict, and the resulting technical solutions are all within the protection scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0019] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0020] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0021] The large-scale grid connection of renewable energy sources has led to frequent problems such as grid voltage dips, harmonic interference, and active power imbalances, necessitating efficient energy storage technologies to ensure grid stability. Superconducting energy storage is one such technology for addressing the stability issues of new energy grid connection. The grid-connected converter design schemes for related superconducting energy storage systems mainly fall into two categories: one employs a topology of a single superconducting energy storage magnet and a modular converter, suitable for low-power, low-capacity scenarios; the other achieves power expansion by increasing the current-carrying capacity and volume of a single superconducting magnet, assuming uniform magnet conditions and charging / discharging according to a fixed power distribution mode. However, these technologies do not consider the control challenges caused by differences in the energy storage capacity of multiple modules. Technical problems in this field include limited power expansion, low reliability, and a lack of multi-module control.

[0022] To address the aforementioned technical problems of limited power expansion, low reliability, and lack of multi-module control, this invention proposes a grid-connected converter topology, method, device, equipment, medium, and product for energy storage arrays. The implementation details of this invention are described below. The following content is only for ease of understanding and is not essential for implementing this solution.

[0023] Example One In this embodiment, a grid-connected converter topology for an energy storage array is provided, comprising: at least two superconducting energy storage modules; choppers corresponding one-to-one with the superconducting energy storage modules, with the input terminal of each chopper electrically connected to the output terminal of the corresponding superconducting energy storage module; an inverter, with the output terminal of each chopper electrically connected to the input terminal of the inverter; and a common bus connected to the inverter for collecting the electrical energy from all the superconducting energy storage modules.

[0024] With the large-scale grid connection of renewable energy sources such as wind and solar power, the power grid's demand for energy storage systems continues to grow. Related technologies rely on single or large superconducting magnets, which are limited by the magnets' current-carrying and voltage-resistance properties, making expansion difficult and presenting a single point of failure; once the magnet or the corresponding current transformer fails, the entire system fails. Simultaneously, the flexibility of energy transmission and grid connection adaptation is insufficient, making it difficult to meet the grid demands in different scenarios, leading to the need to construct efficient, reliable, and scalable grid-connected topologies. The technical problem this embodiment aims to solve is how to construct an array topology with flexible expansion capabilities and dispersed fault risks to achieve bidirectional energy transmission and grid connection adaptation.

[0025] In this embodiment, the topology includes at least two superconducting energy storage modules, corresponding choppers, inverters, and a common bus. The superconducting energy storage modules are made of superconducting materials, exhibiting zero resistance in a superconducting state, enabling efficient energy storage and featuring fast charging / discharging speeds and high energy density. The choppers are bidirectional half-bridge DC-DC topologies, serving as DC-DC power conversion devices capable of bidirectional energy transfer and used to regulate voltage and current. Each chopper input is connected to the output of its corresponding superconducting energy storage module. The inverters employ a modular multilevel topology, composed of multiple sub-modules connected in series. They convert AC and DC power, adapting to grid parameters. Their input is connected to the chopper output, and their output is connected to the common bus, which collects the energy from all modules and connects them to the grid.

[0026] The technical solution in this embodiment employs a combined topology of multiple superconducting energy storage modules with corresponding choppers, inverters, and a common bus. The multi-module design allows for flexible addition or removal of modules according to grid needs without topology reconstruction, overcoming the power and capacity limitations of a single magnet and adapting to different scenarios from small microgrids to large power grids. The array structure disperses fault risks; if a single module fails, the remaining modules can continue to operate normally, preventing overall system failure and improving reliability. Simultaneously, the bidirectional chopper ensures bidirectional energy transmission, the modular multilevel inverter ensures grid-connected power quality, and the common bus enables efficient energy aggregation.

[0027] Example Two Figure 1 A schematic diagram of an AC aggregation topology for an energy storage array grid-connected converter topology provided in an embodiment of the present invention is shown below. Figure 1 As shown, based on the above embodiment, the common bus is a common AC bus, and the output terminal of the inverter is connected to the common AC bus.

[0028] The technical problem this embodiment aims to solve is how to achieve an AC aggregation topology that adapts to distributed inverter scenarios. In some energy storage applications, such as distributed renewable energy grid-connected systems, each energy storage module needs to independently complete power conversion before aggregation and grid connection to improve system flexibility and fault tolerance.

[0029] In this embodiment, based on the topology of Embodiment 1, the common bus is a common AC bus, and the inverter output is directly connected to this bus. Each superconducting energy storage module is first connected to a corresponding bidirectional half-bridge DC-DC chopper. The chopper regulates the module's charging and discharging current to achieve bidirectional energy transfer. The chopper output is connected to modular multilevel inverters, which convert the DC power output from each module into AC power, adapting to the grid frequency and voltage. All inverter outputs are connected to the common AC bus, which collects the dispersed AC power and directly connects to the grid. The inverter processes of each module are independent, and they receive centralized control signals from the upper-level system via a bus.

[0030] The technical solution in this embodiment sets the common bus as a common AC bus, allowing each superconducting energy storage module to complete power conversion via an independent chopper and inverter before the energy is collected, thus adapting to distributed inverter scenarios. The distributed inverter design allows each module to independently adjust its power conversion parameters, enabling the upper-level system to better control the charging and discharging state of individual modules, improving system control flexibility. When a module or its inverter fails, it can be quickly isolated from the common AC bus without affecting the operation of other modules, further enhancing the system's fault tolerance.

[0031] Example Three Figure 2 This is a schematic diagram of a DC aggregation topology for an energy storage array grid-connected converter topology provided in an embodiment of the present invention. (See diagram below.) Figure 2 As shown, based on the above embodiment, the common bus is a common DC bus, and the output terminal of each chopper and the input terminal of the inverter are electrically connected to the common DC bus.

[0032] The technical problem this embodiment aims to solve is how to realize a DC aggregation topology to adapt to centralized inverter scenarios. In application scenarios such as large-scale energy storage power stations, it is necessary to centrally manage and convert the energy of a large number of energy storage modules in order to reduce equipment costs and simplify the control system.

[0033] In this embodiment, based on the basic topology of Embodiment 1, the common bus is a common DC bus, and the output of each chopper and the input of the inverter are electrically connected to this bus. Each superconducting energy storage module is connected to a bidirectional half-bridge DC-DC chopper. The chopper adjusts the DC power output from each module to a voltage level suitable for the common DC bus before directly connecting it to the common DC bus, thus achieving centralized collection of DC energy from all modules. The common DC bus acts as an energy hub, uniformly transmitting the collected DC power to the modular multilevel inverter. This inverter centrally performs DC-to-AC conversion and, after adapting to grid parameters, achieves grid connection. Control signals from all modules are connected to the upper-level system via a bus, enabling coordinated control of module charging / discharging and inverter operation.

[0034] The technical solution in this embodiment achieves centralized energy collection from multiple modules using a common DC bus, followed by unified inversion via a single inverter, thus adapting to centralized inverter scenarios. The centralized inverter design significantly reduces the number of inverters required, lowering equipment procurement and maintenance costs. It also reduces harmonic sources, facilitating harmonic mitigation through a single inverter and improving grid-connected power quality. The common DC bus simplifies the system's wiring structure and reduces floor space, making it particularly suitable for scenarios requiring centralized management, such as large-scale energy storage power stations. Furthermore, the DC collection method shortens the energy transmission path, reducing conversion losses. Combined with the voltage regulation function of the bidirectional chopper, it maintains stable bus voltage, ensuring efficient transmission and centralized conversion of energy from multiple modules, thereby improving the system's economy and reliability.

[0035] Example Four Figure 3 This is a flowchart illustrating a grid-connected converter topology and method for an energy storage array provided in an embodiment of this application, as shown below. Figure 3 As shown, in the technical solution of this embodiment, a grid-connected control method for a grid-connected converter topology of an energy storage array based on any of the above embodiments is provided, including: step S01, determining the number of superconducting energy storage modules to be started according to the power demand of the grid; step S02, determining the cooperative control mode of the topology according to the status of the common bus and / or preset instructions; step S03, performing three-loop control on the superconducting energy storage modules to be started in the topology based on the cooperative control mode.

[0036] The technical problem this embodiment aims to solve is how to perform grid-connected control of an energy storage array grid-connected converter topology. While multi-module superconducting energy storage array topologies solve the problems of capacity expansion and reliability, they also bring complex control challenges. Existing control strategies are mostly designed for single-module systems and cannot adapt to the needs of multi-module collaborative operation, easily leading to problems such as mismatch between the number of modules started and grid demand, chaotic switching of operating modes, and poor power quality control. For example, when grid demand fluctuates, it is impossible to determine the number of modules to start, resulting in power excess or deficiency; the lack of a unified mode switching logic leads to chaotic module operating states, affecting grid-connected stability. Therefore, there is a problem in the field of efficient grid-connected control technology for multi-module array topologies.

[0037] In this embodiment, the control method includes three steps. Step S01: Determine the number of modules to be started based on the power demand of the power grid. Based on the rated power of a single superconducting energy storage module, calculate the number of modules required to meet the grid demand, ensuring that power supply matches demand. Step S02: Determine the collaborative control mode. The system monitors the voltage status of the common bus in real time and / or receives preset instructions from the upper-level system. Combining both, it determines the appropriate mode and switches between modes. Step S03: Implement three-loop control. Each started module uses this control framework. The outer energy loop outputs a voltage reference value based on the stored energy, the middle voltage loop tracks this value and outputs a current reference value, and the inner current loop controls the inverter to output active / reactive current. Module control is achieved through hierarchical linkage.

[0038] The technical solution of this embodiment achieves efficient management and control of the grid-connected converter topology of the energy storage array through a three-step control method: determining the number of modules to be started, selecting the control mode, and implementing three-loop control. Step S01 ensures that the number of modules started matches the power demand of the grid, avoiding power waste or insufficiency. Step S02 realizes intelligent switching of control modes, ensuring stable operation of the system under different operating conditions, such as automatically entering charging mode when the bus voltage is higher than the threshold and entering discharging mode when it is lower than the threshold. The three-loop control hierarchy in step S03 achieves global energy management through the energy loop, stabilizes the bus voltage through the voltage loop, and ensures grid-connected power quality through the current loop, effectively suppressing harmonic interference, improving grid voltage stability, and comprehensively solving the technical problems of grid-connected control of multi-module arrays.

[0039] Example Five Figure 5 This is a schematic flowchart of a charging mode control method provided in an embodiment of the present invention; Figure 6 This is a schematic flowchart of a discharge mode control method provided in an embodiment of the present invention; Figure 7 This is a schematic flowchart illustrating a standby mode control method provided in an embodiment of the present invention. Figure 5 , Figure 6 ,Figure 7 As shown, based on the above embodiments, the collaborative control mode includes: charging mode, discharging mode, and standby mode; the preset commands include charging commands and discharging commands issued by the upper-level system; if a charging command is received from the upper-level system or the common bus voltage is higher than the charging threshold, the system enters charging mode; if a discharging command is received from the upper-level system or the common bus voltage is lower than the discharging threshold, the system enters discharging mode; after charging is completed, if no discharging command is received or no bus voltage is detected to be lower than the threshold, the system enters standby mode.

[0040] During operation, multi-module superconducting energy storage arrays need to dynamically switch operating modes based on factors such as grid conditions and their own energy storage status to achieve efficient energy management and stable grid support. The technical problem this embodiment aims to solve is how to determine the cooperative control mode of the topology.

[0041] In this embodiment, the coordinated control mode includes three modes: charging, discharging, and standby, and defines the mode triggering conditions and switching logic. The charging mode is triggered by receiving a charging command from the upper-level system or detecting that the common bus voltage is higher than the charging threshold; meeting either condition initiates the switch to this mode. The discharging mode is triggered by receiving a discharging command from the upper-level system or detecting that the common bus voltage is lower than the discharging threshold; similarly, meeting either condition initiates the switch. The standby mode is triggered after charging is complete, and automatically enters this mode when the system has not received a discharging command and has not detected that the bus voltage is lower than the threshold. The switching of the three modes is based on a dual judgment logic of command and status, ensuring that the mode switching matches the grid demand and system status.

[0042] The technical solution of this embodiment determines the topology operation mode by defining three cooperative control modes and a dual triggering logic for commands and states. The dual triggering mechanism of the charging mode responds to the grid's active charging scheduling commands and automatically absorbs excess power from the bus. For example, when a sudden increase in photovoltaic output leads to a rise in bus voltage, the system can automatically enter charging mode to store energy. The design of the discharging mode ensures that when the grid needs power support, the system can respond promptly to commands or voltage anomaly signals and quickly release energy, such as automatically discharging to compensate for grid voltage dips. The standby mode maintains the module state when the system is idle, ensuring a timely response to demand through balanced power and supplementary charging.

[0043] Example Six Based on the above embodiments, step S03, which is a three-loop control step for the superconducting energy storage modules that need to be started in the topology based on the cooperative control mode, includes: step S31, outputting a voltage reference value according to the energy stored in the module through the energy loop; step S32, outputting a current reference value by tracking the voltage reference value through the voltage loop; and step S33, controlling the inverter to output active current and reactive current by tracking the current reference value through the current loop.

[0044] When multi-module superconducting energy storage arrays are connected to the grid, they must simultaneously meet the requirements of energy distribution and high-quality grid power. Existing dual-loop control strategies lack comprehensive energy management, focusing only on voltage and current regulation. This can easily lead to energy imbalance among modules and makes it difficult to ensure power quality control under different operating conditions. For example, when there are significant differences in the energy levels of multiple modules, control solely through voltage and current loops can result in abnormal voltage in modules with low energy levels. Furthermore, current regulation may introduce harmonics, affecting grid stability. There is a technical challenge in this field to achieve both energy management and power quality assurance through hierarchical control.

[0045] In this embodiment, the three-loop control achieves control through hierarchical linkage. Step S31: The energy loop, based on instructions from the upper-level system and the actual stored energy of each superconducting energy storage module (calculated through current detection), formulates a personalized energy management strategy and outputs the corresponding voltage reference value to ensure energy allocation matches the module state. Step S32: The voltage loop tracks the voltage reference value output by the energy loop in real time, stabilizes the DC bus voltage through closed-loop control to prevent voltage fluctuations from affecting module operation, and simultaneously outputs a current reference value. Step S33: The current loop tracks the current reference value output by the voltage loop, controls the modular multilevel inverter to output active and reactive currents that meet grid requirements, and suppresses harmonic interference.

[0046] The technical solution in this embodiment achieves the dual goals of energy management and grid-connected power quality assurance through hierarchical linkage control of the energy loop, voltage loop, and current loop. The energy loop addresses the issue of power imbalance among multiple modules. For example, in charging mode, it outputs different voltage reference values ​​based on the current differences of each module, achieving power balance through weighted power allocation. The voltage loop stabilizes the DC bus voltage, providing a stable operating environment for each module and preventing charging and discharging anomalies caused by voltage fluctuations. The current loop controls the inverter output current, ensuring that active and reactive power are delivered on demand, effectively reducing grid-connected harmonic content and improving grid voltage stability and frequency compliance. This hierarchical control logic enables the system to achieve both micro-level current and voltage regulation and macro-level energy coordination, meeting the stringent requirements of the power grid for energy management and power quality of energy storage systems.

[0047] Example Seven Figure 4This is a schematic diagram of the structure of an energy storage array grid-connected converter topology and device provided in an embodiment of this application, as shown below. Figure 4 As shown, in the technical solution of this embodiment, a grid-connected control device for a grid-connected converter topology of an energy storage array based on any of the above embodiments is provided, including: a quantity confirmation module, used to determine the number of superconducting energy storage modules that need to be started according to the power demand of the grid; a mode selection module, used to determine the cooperative control mode of the topology according to the status of the common bus and / or preset instructions; and a three-loop control module, used to perform three-loop control on the superconducting energy storage modules that need to be started in the topology based on the cooperative control mode.

[0048] Other technical features of this embodiment correspond to those of the above embodiments, and will not be repeated here.

[0049] Example Eight In the technical solution of this embodiment, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, it implements the method of any of the above embodiments.

[0050] In the technical solution of this embodiment, an electronic device is provided, including a processor and a memory. The memory stores a computer program, and the processor executes the computer program to implement the method of any of the above embodiments.

[0051] In the technical solution of this embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the method of any of the above embodiments.

[0052] The processor may include, but is not limited to, one or more processors or microprocessors. Each processor may be implemented as an Application Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Digital Signal Processing Device (DSPD), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), controller, microcontroller, microprocessor, or other electronic component, for performing the methods in the above embodiments. The computer-readable storage medium may be implemented by any type of volatile or non-volatile storage device or a combination thereof, and may include, but is not limited to, random access memory (RAM), read-only memory (ROM), flash memory, EPROM memory, EEPROM memory, registers, computer storage media (e.g., hard disk, floppy disk, solid-state drive, removable disk, CD-ROM, DVD-ROM, Blu-ray disc, etc.).

[0053] Computer-readable storage media may also store at least one computer-executable program / instruction, such as computer-readable instructions. Computer-readable storage media include, but are not limited to, volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and / or cache memory. Computer-readable storage media may include, for example, read-only memory (ROM), hard disk, flash memory, etc. For example, a non-transitory computer-readable storage medium may be connected to a computing device such as a computer, and then, when the computing device executes the computer-readable instructions stored on the computer-readable storage medium, the various methods described above can be performed.

[0054] In addition, the computer device may also include (but is not limited to) a data bus, an input / output (I / O) bus, a display, and input / output devices (e.g., a keyboard, mouse, speakers, etc.). The processor can communicate with external devices via the I / O bus through a wired or wireless network. In one embodiment, the at least one computer-executable instruction may also be compiled into or comprise a software product / computer program product, wherein one or more computer-executable instructions, when executed by the processor, perform the steps of the various functions and / or methods in the embodiments described herein.

[0055] Example Nine Based on the above embodiments, this embodiment provides an application example.

[0056] This application example belongs to the field of superconducting energy storage technology, specifically involving the converter topology design and operation control methods for superconducting energy storage systems connected to the power grid. Currently, the large-scale grid connection of renewable energy sources such as wind and solar power has optimized the energy structure of the power system. However, due to their randomness and instability, problems such as grid voltage dips, harmonic interference, and active power imbalances frequently occur, necessitating efficient energy storage technologies to ensure grid stability. Superconducting energy storage, with its advantages of fast response speed, high energy density, and high charging and discharging efficiency, can flexibly manage grid faults and provide transient active power support, becoming one of the core technologies for solving the stability problem of new energy grid connection.

[0057] Currently, the grid-connected converter design schemes of existing superconducting energy storage systems are mainly divided into two categories: one is to adopt a topology structure of "single superconducting energy storage magnet + modular converter", which stores energy through a single magnet and connects directly to the grid through the converter, and is suitable for low-power and small-capacity scenarios; Secondly, power capacity is increased by expanding the current-carrying capacity and volume of a single superconducting magnet. The converter control strategy adopts a dual-loop control of "voltage loop + current loop," assuming that the magnet states are consistent and charging and discharging are performed according to a fixed power distribution mode. Neither of these two approaches involves the coordinated control of multiple superconducting energy storage modules, and both rely on a single magnet or a large magnet to achieve the energy storage function.

[0058] The existing technology has three major flaws, as follows: First, power and capacity expansion is limited: due to the limitations of the superconducting magnet's own current carrying capacity, voltage resistance, and spatial size, the power and capacity of a single magnet or a large magnet are difficult to exceed the upper limit, which cannot meet the grid's demand for large-capacity energy storage. Second, the system has low reliability and short lifespan: the “single magnet / large magnet” design has a single point of failure. If the magnet or the corresponding strain gauge fails, the entire energy storage system will be decommissioned. In addition, frequent charging and discharging can easily lead to the accumulation of differences in magnet characteristics, further shortening the system lifespan. Third, the lack of coordinated control leads to poor safety: the existing control strategy assumes that all magnets are in the same state and charge and discharge according to the average power. However, in actual operation, due to differences in their own power consumption and accumulated errors over time, the amount of electricity stored in the magnets will inevitably be different. Continuing to distribute according to the average power will cause the voltage of the magnet with low electricity to rise abnormally, reducing the safety and reliability of the superconducting magnets, and even causing failure.

[0059] This solution aims to address three core challenges of existing superconducting energy storage systems: overcoming the power / capacity limitations of a single magnet to enable flexible expansion of the system's power and capacity; eliminating the risk of single points of failure, improving system reliability, and extending overall service life; and resolving control challenges caused by differences in the energy storage capacity of multiple modules, achieving energy balance through intelligent collaborative control, and ensuring safe system operation.

[0060] This solution utilizes a "superconducting energy storage multi-module parallel array topology (including magnet unit, chopper, inverter, and common bus) + three-loop control (energy loop, voltage loop, and current loop) + multi-mode coordinated charging and discharging strategy" to achieve flexible expansion of the energy storage system's power / capacity, eliminate single fault points, balance the power of multiple modules, and ensure grid connection stability and system safety.

[0061] This solution consists of two parts: topology design and operation control methods.

[0062] (1) Topology design ①Core components: Superconducting energy storage magnet modules (SEMS): The quantity is N (N≥2, which can be expanded according to needs), used to store electrical energy, and each module operates independently; Superconducting energy storage chopper DC-DC: It corresponds one-to-one with each magnet module and adopts a bidirectional half-bridge DC-DC topology to realize bidirectional energy transfer between the magnet module and the bus. Superconducting energy storage inverter: It adopts a modular multilevel converter topology to realize the conversion of DC power to AC power and adapt to the grid frequency and voltage; Common busbar: divided into common AC busbar ( Figure 1 ) and common DC bus ( Figure 2 In the AC converged topology, the magnet module is directly connected to the common AC bus and grid via a chopper and inverter; in the DC converged topology, the magnet module is first connected to the common DC bus via a chopper, and then connected to the grid via an inverter.

[0063] ②Connection relationship: The output of each superconducting energy storage magnet module is connected to the input of the corresponding chopper. The chopper output is connected to the common AC bus or the common DC bus according to the topology type (AC / DC convergence). The common AC bus is directly connected to the grid, while the common DC bus needs to be converted by an inverter before being connected to the grid. The control signals of all modules are connected to the upper-level control system through the bus to achieve centralized and coordinated control.

[0064] ③Work method: After the upper-level system issues a charge and discharge command, the chopper adjusts the charge and discharge current of the magnet module, the inverter adjusts the power and phase of the grid-connected power, and the common bus realizes the energy collection of multiple modules and grid connection, finally completing the complete process of "magnet energy storage - energy conversion - grid interaction".

[0065] (2) Operation control method The control method is based on "three-loop control and with multi-mode coordination as the core", as detailed below: ① Basic control framework: Three-loop control (each module uses this independently): Outer loop (energy loop): Based on the superior command and the energy stored in the module, formulate energy management strategies and output voltage reference values; Middle loop (voltage loop): Track the voltage reference value output by the energy loop, stabilize the DC bus voltage, and output current reference values; Inner loop (current loop): Track the current reference value output by the voltage loop, control the active / reactive current output by the inverter, and ensure grid-connected power quality.

[0066] ② Method for determining the number of modules: First, determine the number of modules that need to be activated based on the power demand of the power grid, as shown in the following expression:

[0067]

[0068] In the formula, Power required by the power grid; This refers to the rated power of the superconducting energy storage module; To determine the number of superconducting energy storage modules to be loaded at startup.

[0069] ③ Sub-mode collaborative control strategy: The specific control strategy for the superconducting energy storage module array is as follows: 1) Charging mode: When the superconducting energy storage array receives a charging command (preset instruction) from the upper-level system or detects that the bus voltage is higher than the charging threshold, the superconducting energy storage converter will detect the current of each superconducting magnet, according to the expression:

[0070] and expressions:

[0071] in: Indicates the first The instantaneous power of each energy storage magnet module, Indicates the first The voltage of each energy storage magnet module Indicates the first The current of each energy storage magnet module Indicates the first The energy stored in each energy storage magnet module Indicates the first The inductance of an energy storage magnet module, Represents the first in the energy storage array One energy storage magnet , This indicates the total number of energy storage magnet arrays. Indicates the charging and discharging time.

[0072] If the current of each energy storage magnet is the same, it means that the current charge of each energy storage magnet is the same. In this case, the energy storage converter of each energy storage magnet will charge the energy storage magnet to the rated current according to the rated power, that is, the fully charged state. Otherwise, if the current of each magnet is detected to be different, it means that the current charge of each energy storage magnet is different. According to the actual charge of each energy storage magnet, the system weightedly allocates the charging power to each energy storage magnet, so that the charge of each energy storage magnet is quickly balanced and synchronously charged to the rated current to complete the charging.

[0073] 2) Discharge mode: When the superconducting energy storage array receives a discharge command (preset instruction) from the upper-level system or detects that the bus voltage is lower than the charging threshold, the superconducting energy storage converter will detect the current of each superconducting magnet, according to the expression:

[0074] and expressions:

[0075] The current of each energy storage magnet in the array is detected. If the current of each energy storage magnet is the same, it means that the energy storage magnets have the same charge, and each superconducting magnet discharges at the same power until discharge is complete. However, in reality, due to the differences between each magnet, there will inevitably be differences in charge during charging and discharging. If the discharge is still carried out in the same power manner, the voltage of the energy storage magnet with lower charge will increase, reducing the safety and reliability of the superconducting magnet. This invention proposes the following control method when the discharge mode current of the energy storage magnets is different: Assuming that the current of each magnet is different, it means that the current stored energy of each magnet is different, and the maximum current I among all energy storage magnets in the array is calculated. max and minimum current I min After the difference is calculated, it is then compared with the rated current I. rate If the result of the division is greater than or equal to the set value T up (The T) up T low The value represents the upper and lower limits of the energy storage magnet fault threshold, respectively. If the current of one of the energy storage magnets is too low, the array cannot complete the discharge operation normally, a system fault is reported, and the system is shut down for maintenance. max and minimum current I min After the difference is calculated, it is then compared with the rated current I. rate The result of the division calculation is within the set value T.up and T low The difference indicates that the current of one of the energy storage magnets is slightly lower than that of the other energy storage magnets in the system. In order to meet the system's discharge requirements, the energy storage unit array adopts derating operation, and the energy storage converter allocates the discharge power according to the actual amount of electricity until the discharge is completed.

[0076] (3) Standby mode: After charging is complete, the energy storage module enters standby mode unless a discharge command (preset instruction) is received or the bus voltage is detected to be below a threshold. In standby mode, the current of each energy storage magnet is checked for consistency. If they are not identical, power is weighted according to the actual stored energy of each superconducting magnet to ensure rapid, balanced, and synchronous charging to the rated current. If the current of each superconducting magnet is found to be identical, it is determined whether the current value is less than the rated current. If it is less than the rated current, each magnet is charged to the rated current at the rated power and maintained thereafter.

[0077] This application example has the following beneficial technical effects: 1) Flexible expansion and strong adaptability: The number of superconducting magnet modules can be increased or decreased according to the power / capacity requirements of the power grid without reconfiguring the topology, adapting to different scenarios from small microgrids to large power grids; 2) High reliability and extended lifespan: The array design disperses the risk of failure. The failure of a single module does not affect the operation of the overall system. The modular structure facilitates the repair / replacement of the failed module, and the overall system lifespan is extended by more than 30%. 3) Intelligent control and high safety: By using current detection and weighted power distribution, the system solves the problem of power difference between multiple modules, avoids abnormal magnet voltage, and improves the safety of system operation; at the same time, the three-loop control ensures the quality of grid-connected power and reduces interference to the power grid. 4) Excellent economic efficiency and low marginal cost: By using multiple low-power modules instead of a single high-power module, the mass production cost of the modules is lower than the cost of customizing large magnets, and expansion only requires the addition of standardized modules, significantly reducing marginal costs. The key to this application example is: 1) Key topology: The bidirectional energy transmission capability of the bidirectional half-bridge DC-DC chopper ensures flexible charging and discharging of the magnet module; the topology design of the modular multilevel inverter ensures grid-connected power quality; 2) Key control strategies: Hierarchical linkage of three-loop control (energy loop-voltage loop-current loop) to achieve precise control; current detection and weighted power allocation algorithms in different modes to solve the power balance problem.

[0078] Furthermore, in this application example, the superconducting energy storage magnet module, made of superconducting materials, has zero resistance in its superconducting state, enabling efficient energy storage and featuring fast charging and discharging speeds and high energy density. The bidirectional half-bridge DC-DC chopper, a DC-DC power conversion device, includes two half-bridge switching circuits, enabling bidirectional energy transfer from input to output and vice versa, used for voltage and current regulation. The modular multilevel inverter, composed of multiple sub-modules (such as half-bridge sub-modules) connected in series, allows control of the output voltage level through sub-module switching, offering advantages such as low output harmonics and high withstand voltage ratings, making it suitable for medium and high voltage power grids.

[0079] Based on the above, this invention discloses a topology and operation control method for a superconducting energy storage multi-module array grid-connected converter. The superconducting energy storage multi-module parallel array includes superconducting energy storage magnet units, a superconducting energy storage chopper, a superconducting energy storage inverter, and a common AC bus or a common DC bus. The superconducting energy storage magnet units are connected to the common AC bus for grid connection via the superconducting energy storage chopper and the superconducting energy storage inverter, or they are connected to the common DC bus via the superconducting energy storage chopper and then connected to the grid via the superconducting energy storage inverter. This invention can expand the power and capacity of the superconducting energy storage system according to the application scenario; the array design not only reduces the risk of system decommissioning due to a single point of failure, but also facilitates maintenance, repair, or replacement of faulty modules, thereby extending the service life of the overall system.

[0080] This invention provides a superconducting energy storage multi-module array grid-connected converter topology. The superconducting energy storage multi-module parallel array system includes superconducting energy storage magnet modules, superconducting energy storage choppers, superconducting energy storage inverters, and a common AC bus. Each energy storage magnet module is connected to the common AC bus through a superconducting energy storage chopper and a superconducting energy storage inverter. This invention provides a multi-module array grid-connected converter topology for a superconducting energy storage system. The superconducting energy storage multi-module parallel array system includes a superconducting energy storage magnet module, a superconducting energy storage chopper, a superconducting energy storage inverter, and a common DC bus. The energy storage magnet units are collected to the common DC bus via the superconducting energy storage chopper and then connected to the grid via the superconducting energy storage inverter. This invention provides a superconducting energy storage multi-module array grid-connected converter, whose operation control method is as follows: After receiving the charging and discharging command from the upper-level system, the energy storage converter of each energy storage magnet unit judges the overall status of the magnet array according to the system-level diagnosis. The judged status includes the energy storage of each magnet unit, the charging and discharging control system status, the ambient temperature status, and the AC / DC bus status. Under the condition that the status is met, the energy storage magnet array realizes charging and discharging control according to the charging and discharging command of the upper level or realizes automatic charging and discharging control by detecting the AC bus voltage. A single superconducting energy storage module adopts a three-loop control method for charging and discharging control: the outer loop is the energy loop, which realizes the energy management function; the middle loop is the voltage loop, which is used to stabilize the DC bus voltage; and the inner loop is the current loop, which is used to enable the inverter to output the active and reactive current given by the outer loop.

[0081] This invention provides an operation control method for a superconducting energy storage system, wherein the specific steps for determining which superconducting energy storage module needs to be activated to meet grid power demand include: The number of superconducting energy storage magnet modules that need to be activated to meet the power demand of the power grid is determined by a judgment expression, which is as follows:

[0082]

[0083] In the formula, Power required by the power grid; This refers to the rated power of a single superconducting energy storage module; To determine the number of superconducting energy storage modules to be loaded.

[0084] This invention provides an operation control method for a superconducting energy storage system, wherein the specific control methods for the charging, discharging, and standby modes of the plurality of superconducting energy storage modules include: (1) Charging mode: When the superconducting energy storage array receives a charging command from the upper-level system or detects that the bus voltage is higher than the charging threshold, the superconducting energy storage converter will detect the current of each superconducting magnet, according to the expression:

[0085] and expression

[0086] in: Indicates the first The instantaneous power of each energy storage magnet module, Indicates the first The voltage of each energy storage magnet module Indicates the first The current of each energy storage magnet module Indicates the first The energy stored in each energy storage magnet module Indicates the first The inductance of an energy storage magnet module, Represents the first in the energy storage array One energy storage magnet , This indicates the total number of energy storage magnet arrays. Indicates the charging and discharging time.

[0087] If the current of each energy storage magnet is the same, it means that the current charge of each energy storage magnet is the same. In this case, the energy storage converter of each energy storage magnet will charge it to its rated current according to its rated power, i.e., fully charged. Otherwise, if the current of each magnet is detected to be different, it means that the current charge of each energy storage magnet is different. Based on the actual charge of each energy storage magnet, the system weightedly allocates charging power to each energy storage magnet, so that the charge of each energy storage magnet is quickly balanced and synchronously charged to the rated current, completing the charging process. The weighted allocation of charging power according to the actual stored energy is solved by a proportional allocation algorithm with "energy gap" as the weight. The calculation expression is as follows:

[0088] in: This indicates that calculations need to be performed on the first... The charging power of each energy storage magnet module Indicates the first The rated energy storage capacity of each energy storage magnet module, Indicates the first The actual energy stored in each energy storage magnet module This indicates the total charging power that the array needs to allocate. Represents the first in the energy storage array One energy storage magnet , This indicates the total number of energy storage magnet arrays.

[0089] (2) Discharge mode: When the superconducting energy storage array receives a discharge command from the upper-level system or detects that the bus voltage is lower than the charging threshold, the superconducting energy storage converter will detect the current of each superconducting magnet, according to the expression:

[0090] and expression

[0091] The current of each energy storage magnet in the array is detected. If the current of each energy storage magnet is the same, it means that the energy storage magnets have the same charge, and each superconducting magnet discharges at the same power until discharge is complete. However, in reality, due to the inherent differences between each magnet, there will inevitably be differences in charge during charging and discharging. If the discharge is still performed at the same power, the voltage of the energy storage magnet with lower charge will increase, reducing the safety and reliability of the superconducting magnet. This invention proposes a control method for situations where the discharge mode current of the energy storage magnets is different: assuming that the current of each magnet is different, it means that the current stored energy of each magnet is different, and the maximum current value among all energy storage magnets in the array is calculated. I max and minimum current I min After calculating the difference, compare it with the rated current. I rate If the result of the division is greater than or equal to the set value T up (the aforementioned) T up , T low The value is a set threshold, representing the upper and lower limits of the energy storage magnet fault threshold, respectively. If the current of one of the energy storage magnets is too low, the array cannot complete the discharge operation normally, a system fault is reported, and the system is shut down for maintenance. I max and minimum current I min After calculating the difference, compare it with the rated current. I rate The result of the division calculation is within the set value. T up and T low The discrepancy indicates that the current of one energy storage magnet is slightly lower than that of the others in the system. To meet the system's discharge requirements, the energy storage unit array operates under derating conditions, and the energy storage converter allocates discharge power according to the actual amount of electricity supplied, until discharge is complete. This weighted allocation of discharge power based on the actual amount of electricity supplied is achieved using a proportional allocation algorithm with the "energy gap" as the weight. The calculation expression is as follows:

[0092] in: This indicates that calculations need to be performed on the first... The discharge power of each energy storage magnet module Indicates the first The rated energy storage capacity of each energy storage magnet module, Indicates the first The actual energy stored in each energy storage magnet module This indicates the total discharge power that the array needs to allocate. Represents the first in the energy storage array One energy storage magnet , This indicates the total number of energy storage magnet arrays.

[0093] (3) Standby mode: After charging is complete, the energy storage module enters standby mode when no discharge command is received or the bus voltage is not detected to be below the threshold. In standby mode, it checks if the current of each energy storage magnet is the same. If not, power is weighted according to the actual stored energy of each superconducting magnet to quickly equalize and synchronously charge each magnet to its rated current. If the current of each superconducting magnet is the same, it checks if the current value is less than the rated current. If it is less than the rated current, each magnet is charged to its rated current at the rated power and maintained thereafter. When the current of each energy storage magnet is not the same, the charging power is weighted according to the actual stored energy using a proportional allocation algorithm with "energy gap" as the weight. The calculation expression is as follows:

[0094] in: This indicates that calculations need to be performed on the first... The charging power of each energy storage magnet module Indicates the first The rated energy storage capacity of each energy storage magnet module, Indicates the first The actual energy stored in each energy storage magnet module This indicates the total charging power that the array needs to allocate. Represents the first in the energy storage array One energy storage magnet , This indicates the total number of energy storage magnet arrays.

[0095] This invention belongs to the field of superconducting energy storage technology, and particularly relates to an operation control method and system for a superconducting energy storage system.

[0096] The rapid development of renewable energy is leading to a high proportion of renewable energy power generation gradually replacing traditional thermal power generation, thus optimizing the energy source structure of the power system and ultimately achieving a green and sustainable power system. However, the large-scale grid connection of renewable energy sources such as wind and solar power also brings problems such as randomness and instability. Therefore, ensuring the stability of the power grid while vigorously developing new energy power systems is an urgent problem to be solved in the power energy sector. Superconducting energy storage can flexibly manage voltage dips and harmonics in the power grid, or provide transient high-power active power support. When the power grid experiences transient voltage drops or surges, or transient active power imbalances, energy can be extracted from superconducting inductors, converted into AC by inverters, and output flexibly adjustable active or reactive power to the grid, thereby ensuring the transient voltage stability and active power balance of the power grid.

[0097] In existing grid-connected converter designs for superconducting energy storage systems, a single superconducting energy storage magnet and a modular converter topology are generally used. However, collaborative control methods for multiple superconducting energy storage modules have not yet been addressed. Due to limitations in the current-carrying capacity and withstand voltage of superconducting magnets, as well as space constraints, the power and capacity of a single superconducting energy storage module are difficult to increase. To meet both energy storage and power requirements, superconducting energy storage needs to employ arrays composed of multiple energy storage magnet modules. However, due to accumulated time errors and differences in individual power consumption, the stored capacity of each superconducting energy storage magnet may vary slightly during charging and discharging. Furthermore, a failure in one set of energy storage magnets in the array can cause the entire superconducting energy storage array to malfunction. Assuming that each magnet in the array has the same charging and discharging parameters will present problems. In actual operating conditions, frequent charging and discharging will inevitably lead to inconsistencies in the states of each magnet. If charging and discharging are performed in a way that distributes power evenly, the superconducting energy storage array cannot reach its optimal dynamic performance. Over time, this will lead to greater and greater differences in the characteristics of each energy storage magnet in the superconducting energy storage array, affecting the lifespan of the superconducting energy storage array.

[0098] The purpose of this invention is to overcome the shortcomings of existing superconducting energy storage systems, such as the difficulty in increasing power and energy, and the problems of power distribution and coordinated control of superconducting energy storage arrays. Based on feedback data, the invention determines the status of each set of magnets in the array in the three states of superconducting energy storage operation: charging state, discharging state, and holding state, and reasonably adjusts the control method so that each set of magnets can achieve optimal dynamic performance and power balance while completing the system command actions.

[0099] The technical solution of the present invention is as follows: A multi-module array grid-connected converter topology for a superconducting energy storage system is disclosed. The superconducting energy storage multi-unit module parallel array system includes superconducting energy storage magnet units, superconducting energy storage converters, and a common AC bus or a common DC bus. The energy storage magnet units are connected to the common AC bus or common DC bus via the superconducting energy storage converters. After receiving charge / discharge commands from the upper-level system via a bus, the energy storage converter of each magnet unit determines the overall status of the magnet array based on system-level diagnostics. The determined status includes the energy storage of each magnet unit, the status of the charge / discharge control system, the ambient temperature, and the AC / DC bus status. Under the condition that the status is satisfied, the energy storage magnet array implements charge / discharge control according to the charge / discharge command from the upper level or achieves automatic charge / discharge control by detecting the bus voltage. A single superconducting energy storage module uses a three-loop control method for charge / discharge control: the outer loop is the energy loop, realizing energy management functions; the middle loop is the voltage loop, used to stabilize the DC bus voltage; and the inner loop is the current loop, used to enable the inverter to output the active and reactive current given by the outer loop.

[0100] A superconducting energy storage system uses choppers and inverters to connect several sets of superconducting energy storage magnet modules to the power grid. The method is characterized by: determining the number of superconducting energy storage modules that need to be loaded to meet the power demand of the power grid and loading the determined superconducting energy storage modules. Furthermore, the specific steps for determining the superconducting energy storage module that needs to be activated to meet the power demand of the power grid include: The number of superconducting energy storage modules that need to be activated to meet the power demand of the power grid is determined by the following expression:

[0101]

[0102] In the formula, Power required by the power grid; This refers to the rated power of the superconducting energy storage module; To determine the number of superconducting energy storage modules to be loaded at startup.

[0103] The specific control strategy for the superconducting energy storage module array is as follows: (1) Charging mode: When the superconducting energy storage array receives a charging command from the upper-level system or detects that the bus voltage is higher than the charging threshold, the superconducting energy storage converter will detect the current of each superconducting magnet, according to the expression:

[0104] and expression

[0105] in: Indicates the first The instantaneous power of each energy storage magnet module, Indicates the first The voltage of each energy storage magnet module Indicates the first The current of each energy storage magnet module Indicates the first The energy stored in each energy storage magnet module Indicates the first The inductance of an energy storage magnet module, Represents the first in the energy storage array One energy storage magnet , This indicates the total number of energy storage magnet arrays. Indicates the charging and discharging time.

[0106] If the current of each energy storage magnet is the same, it means that the current charge of each energy storage magnet is the same. In this case, the energy storage converter of each energy storage magnet will charge it to its rated current according to its rated power, i.e., fully charged. Otherwise, if the current of each magnet is detected to be different, it means that the current charge of each energy storage magnet is different. Based on the actual charge of each energy storage magnet, the system weightedly allocates charging power to each energy storage magnet, so that the charge of each energy storage magnet is quickly balanced and synchronously charged to the rated current, completing the charging process. The weighted allocation of charging power according to the actual stored energy is solved by a proportional allocation algorithm with "energy gap" as the weight. The calculation expression is as follows:

[0107] in: This indicates that calculations need to be performed on the first... The charging power of each energy storage magnet module Indicates the first The rated energy storage capacity of each energy storage magnet module, Indicates the first The actual energy stored in each energy storage magnet module This indicates the total charging power that the array needs to allocate. Represents the first in the energy storage array One energy storage magnet , This indicates the total number of energy storage magnet arrays.

[0108] (2) Discharge mode: When the superconducting energy storage array receives a discharge command from the upper-level system or detects that the bus voltage is lower than the charging threshold, the superconducting energy storage converter will detect the current of each superconducting magnet, according to the expression:

[0109] and expression

[0110] The current of each energy storage magnet in the array is detected. If the current of each energy storage magnet is the same, it means that the energy storage magnets have the same charge, and each superconducting magnet discharges at the same power until discharge is complete. However, in reality, due to the inherent differences between each magnet, there will inevitably be differences in charge during charging and discharging. If the discharge is still performed at the same power, the voltage of the energy storage magnet with lower charge will increase, reducing the safety and reliability of the superconducting magnet. This invention proposes a control method for situations where the discharge mode current of the energy storage magnets is different: assuming that the current of each magnet is different, it means that the current stored energy of each magnet is different, and the maximum current value among all energy storage magnets in the array is calculated. I max and minimum current I min After calculating the difference, compare it with the rated current. I rate If the result of the division is greater than or equal to the set value T up (the aforementioned) T up , T low The value represents the upper and lower limits of the energy storage magnet fault threshold, respectively. If the current of one of the energy storage magnets is too low, the array cannot complete the discharge operation normally, a system fault is reported, and the system is shut down for maintenance. I max and minimum current I min After calculating the difference, compare it with the rated current. I rate The result of the division calculation is within the set value. T up and T low The discrepancy indicates that the current of one energy storage magnet is slightly lower than that of the others in the system. To meet the system's discharge requirements, the energy storage unit array operates under derating conditions, and the energy storage converter allocates discharge power according to the actual amount of electricity supplied, until discharge is complete. This weighted allocation of discharge power based on the actual amount of electricity supplied is achieved using a proportional allocation algorithm with the "energy gap" as the weight. The calculation expression is as follows:

[0111] in: This indicates that calculations need to be performed on the first... The discharge power of each energy storage magnet module Indicates the first The rated energy storage capacity of each energy storage magnet module, Indicates the first The actual energy stored in each energy storage magnet module This indicates the total discharge power that the array needs to allocate. Represents the first in the energy storage array One energy storage magnet , This indicates the total number of energy storage magnet arrays.

[0112] (3) Standby mode: After charging is complete, the energy storage module enters standby mode when no discharge command is received or the bus voltage is not detected to be below the threshold. In standby mode, it checks if the current of each energy storage magnet is the same. If not, power is weighted according to the actual stored energy of each superconducting magnet to quickly equalize and synchronously charge each magnet to its rated current. If the current of each superconducting magnet is the same, it checks if the current value is less than the rated current. If it is less than the rated current, each magnet is charged to its rated current at the rated power and maintained thereafter. When the current of each energy storage magnet is not the same, the charging power is weighted according to the actual stored energy using a proportional allocation algorithm with "energy gap" as the weight. The calculation expression is as follows:

[0113] in: This indicates that calculations need to be performed on the first... The charging power of each energy storage magnet module Indicates the first The rated energy storage capacity of each energy storage magnet module, Indicates the first The actual energy stored in each energy storage magnet module This indicates the total charging power that the array needs to allocate. Represents the first in the energy storage array One energy storage magnet , This indicates the total number of energy storage magnet arrays.

[0114] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention abandons the idea of ​​expanding capacity using a single large superconducting energy storage magnet, and proposes a solution of multiple superconducting energy storage magnet module arrays. Through modular unit combination and intelligent collaborative control, it improves the flexibility of the energy storage system, reduces the marginal cost of the energy storage system, and improves economic efficiency. 2. This invention allows for the expansion of energy storage power and capacity according to different energy storage scenarios. The array design disperses risks, reducing the risk of catastrophic failure due to a single point of failure. The modular design facilitates maintenance, repair, or replacement of individual units without decommissioning the entire system, thereby extending the overall system lifespan. Based on the array arrangement, the energy storage unit achieves high efficiency and good safety through centralized control.

[0115] 3. This invention proposes a charging and discharging strategy for the energy storage magnet array under different current conditions by acquiring the state of the energy storage magnet itself and the state of other energy storage magnets in the array. It realizes the reasonable allocation of the power shared by each energy storage magnet and makes timely adjustments through algorithms to ensure the balance of the power of each energy storage magnet in the array, effectively improving the safety of the system.

[0116] The present invention provides a grid-connected converter AC collection topology for a superconducting energy storage system, as shown below. Figure 1 Several sets of superconducting energy storage modules in the superconducting energy storage system are connected to the grid using choppers and inverters; the start-up load determination module is used to determine which superconducting energy storage modules need to be started to meet the power demand of the grid. Furthermore, the specific steps for determining the superconducting energy storage module that needs to be activated to meet the power demand of the power grid include: The number of superconducting energy storage modules required to be activated to meet the power demand of the power grid is determined by a judgment expression, thereby completing the determination of the superconducting energy storage modules. The judgment expression is as follows:

[0117]

[0118] In the formula, Power required by the power grid; This refers to the rated power of the synchronous machine when it operates in its high-efficiency range. To determine the number of synchronization modules to load at startup.

[0119] The superconducting energy storage array charging mode control strategy is as follows: When the superconducting energy storage array receives a charging command from the upper-level system or detects that the bus voltage is higher than the charging threshold, the superconducting energy storage converter will detect the current of each superconducting magnet, according to the expression:

[0120] and expression

[0121] in: Indicates the first The instantaneous power of each energy storage magnet module, Indicates the first The voltage of each energy storage magnet module Indicates the first The current of each energy storage magnet module Indicates the first The energy stored in each energy storage magnet module Indicates the first The inductance of an energy storage magnet module, Represents the first in the energy storage array One energy storage magnet , This indicates the total number of energy storage magnet arrays. Indicates the charging and discharging time.

[0122] If the current of each energy storage magnet is the same, it means that the current charge of each energy storage magnet is the same. In this case, the energy storage converter of each energy storage magnet will charge it to its rated current according to its rated power, i.e., fully charged. Otherwise, if the current of each magnet is detected to be different, it means that the current charge of each energy storage magnet is different. Based on the actual charge of each energy storage magnet, the system weightedly allocates charging power to each energy storage magnet, so that the charge of each energy storage magnet is quickly balanced and synchronously charged to the rated current, completing the charging process. The weighted allocation of charging power according to the actual stored energy is solved by a proportional allocation algorithm with "energy gap" as the weight. The calculation expression is as follows:

[0123] in: This indicates that calculations need to be performed on the first... The charging power of each energy storage magnet module Indicates the first The rated energy storage capacity of each energy storage magnet module, Indicates the first The actual energy stored in each energy storage magnet module This indicates the total charging power that the array needs to allocate. Represents the first in the energy storage array One energy storage magnet , This indicates the total number of energy storage magnets in the array. State Two: Discharge Mode. When the superconducting energy storage array receives a discharge command from the upper-level system or detects that the bus voltage is below the charging threshold, the superconducting energy storage converter will detect the current of each superconducting magnet, according to the expression:

[0124] and expression

[0125] The current of each energy storage magnet in the array is detected. If the current of each energy storage magnet is the same, it means that the energy storage magnets have the same charge, and each superconducting magnet discharges at the same power until discharge is complete. However, in reality, due to the inherent differences between each magnet, there will inevitably be differences in charge during charging and discharging. If the discharge is still performed at the same power, the voltage of the energy storage magnet with lower charge will increase, reducing the safety and reliability of the superconducting magnet. This invention proposes a control method for situations where the discharge mode current of the energy storage magnets is different: assuming that the current of each magnet is different, it means that the current stored energy of each magnet is different, and the maximum current value among all energy storage magnets in the array is calculated. I max and minimum current I min After calculating the difference, compare it with the rated current. I rate If the result of the division is greater than or equal to the set value T up (the aforementioned) T up , T low The value is a set threshold, representing the upper and lower limits of the energy storage magnet fault threshold, respectively. If the current of one of the energy storage magnets is too low, the array cannot complete the discharge operation normally, a system fault is reported, and the system is shut down for maintenance. I max and minimum current I min After calculating the difference, compare it with the rated current. I rate The result of the division calculation is within the set value. T up and T low The discrepancy indicates that the current of one energy storage magnet is slightly lower than that of the others in the system. To meet the system's discharge requirements, the energy storage unit array operates under derating conditions, and the energy storage converter allocates discharge power according to the actual amount of electricity supplied, until discharge is complete. This weighted allocation of discharge power based on the actual amount of electricity supplied is achieved using a proportional allocation algorithm with the "energy gap" as the weight. The calculation expression is as follows:

[0126] in: This indicates that calculations need to be performed on the first... The discharge power of each energy storage magnet module Indicates the first The rated energy storage capacity of each energy storage magnet module, Indicates the first The actual energy stored in each energy storage magnet module This indicates the total discharge power that the array needs to allocate. Represents the first in the energy storage array One energy storage magnet , This indicates the total number of energy storage magnet arrays.

[0127] State 3: Standby Mode. After charging is complete, the energy storage module enters standby mode when no discharge command is received or the bus voltage is detected to be below the threshold. Upon entering standby mode, it checks if the current of each energy storage magnet is the same. If not, power is weighted according to the actual stored energy of each superconducting magnet to quickly equalize and synchronously charge each magnet to its rated current. If the current of each superconducting magnet is the same, it checks if the current value is less than the rated current. If it is less than the rated current, each magnet is charged to its rated current at the rated power and maintained thereafter. When the current of each energy storage magnet is not the same, the charging power is weighted according to the actual stored energy using a proportional allocation algorithm with "energy gap" as the weight. The calculation expression is:

[0128] in: This indicates that calculations need to be performed on the first... The charging power of each energy storage magnet module Indicates the first The rated energy storage capacity of each energy storage magnet module, Indicates the first The actual energy stored in each energy storage magnet module This indicates the total charging power that the array needs to allocate. Represents the first in the energy storage array One energy storage magnet , This indicates the total number of energy storage magnet arrays.

[0129] The grid-connected converter DC collection topology of the superconducting energy storage system of the present invention is as follows: Figure 2 In the superconducting energy storage system, several sets of superconducting energy storage modules are first collected by DC power through multiple choppers and then connected to the grid through an inverter; the control strategy in charging, discharging and standby modes is the same as in Example 1.

[0130] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

[0131] In the embodiments provided by this invention, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0132] It should be noted that, in this invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element limited by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0133] While the embodiments disclosed in this invention are as described above, the above content is merely for the purpose of facilitating understanding of this invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope disclosed in this invention; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A grid-tied variable topology for energy storage arrays, comprising: The superconducting energy storage module comprises: at least two superconducting energy storage modules; a chopper corresponding to each superconducting energy storage module, the input end of each chopper being electrically connected to the output end of the corresponding superconducting energy storage module; an inverter, the output end of each chopper being electrically connected to the input end of the inverter; a common bus connected to the inverter, for collecting the electric energy of all superconducting energy storage modules.

2. The topology of claim 1, wherein, The common bus is a common AC bus, and the output end of the inverter is connected to the common AC bus.

3. The topology of claim 1, wherein, The common bus is a common DC bus, and the output end of each chopper and the input end of the inverter are electrically connected to the common DC bus.

4. A grid-connected control method of a grid-connected inverter topology based on the energy storage array of any one of claims 1 to 3, characterized in that, The method comprises: Step S01, determining the number of superconducting energy storage modules that need to be started according to the grid demand power; Step S02, determining the cooperative control mode of the topology according to the state of the common bus and / or a preset instruction; Step S03, performing three-loop control on the superconducting energy storage modules that need to be started in the topology based on the cooperative control mode.

5. The method of claim 4, wherein, The cooperative control mode comprises: a charging mode, a discharging mode, and a standby mode; and the preset instruction comprises a charging command issued by a superior system and a discharging command issued by the superior system. If a charging command is received from the superior system or the voltage of the common bus is higher than a charging threshold, the charging mode is entered. If a discharging command is received from the superior system or the voltage of the common bus is lower than a discharging threshold, the discharging mode is entered. After charging is completed, if no discharging command is received or the voltage of the common bus is not detected to be lower than the threshold, the standby mode is entered.

6. The method of claim 4, wherein, The step S03 of performing three-loop control on the superconducting energy storage modules that need to be started in the topology based on the cooperative control mode comprises: Step S31, outputting a voltage reference value according to the energy storage amount of the module through an energy loop; Step S32, outputting a current reference value by tracking the voltage reference value through a voltage loop; Step S33, controlling the active current and the reactive current output by the inverter by tracking the current reference value through a current loop.

7. A grid-tie control device based on the grid-tie topology of the energy storage array of any one of claims 1 to 3, characterized in that, The method comprises: a number confirmation module configured to determine the number of superconducting energy storage modules that need to be started according to the grid demand power; a mode selection module configured to determine the cooperative control mode of the topology according to the state of the common bus and / or a preset instruction; a three-loop control module configured to perform three-loop control on the superconducting energy storage modules that need to be started in the topology based on the cooperative control mode.

8. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the method of any one of claims 4 to 6.

9. An electronic device comprising a processor and a memory, characterized in that The computer program is stored on the memory and executed by the processor to implement the method of any one of claims 4 to 6.

10. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to implement the method of any one of claims 4 to 6.

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