Energy storage apparatus and design method therefor, and electronic device and storage medium

Abstract

The present application relates to the field of energy storage. Disclosed are an energy storage apparatus, a design method for the energy storage apparatus, an electronic device, and a computer-readable storage medium. The energy storage apparatus comprises: a direct-current energy storage valve, which is used for providing a direct-current voltage; and a three-phase modular multilevel converter circuit, wherein a direct-current side thereof is connected to two ends of the direct-current energy storage valve, and the three-phase modular multilevel converter circuit comprises two or more modular multilevel converter sub-modules, each modular multilevel converter sub-module being a full-bridge sub-module or a half-bridge sub-module, and the proportion of the number of full-bridge sub-modules among the two or more modular multilevel converter sub-modules being determined on the basis of a target adjustment range of the direct-current voltage. Compared with the relevant art, the energy storage apparatus, the design method for the energy storage apparatus, the electronic device, and the computer-readable storage medium which are provided in the embodiments of the present application have the advantages of reducing the design complexity of an energy storage apparatus under different voltage requirements and improving the design efficiency of an energy storage apparatus.

Description

Energy storage device and design method thereof, electronic device and storage medium CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Chinese patent application No. 2024102391709, filed on March 1, 2024, entitled “Energy storage device and design method thereof, electronic device and storage medium,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of energy storage, and in particular to an energy storage device, a design method for an energy storage device, an electronic device, and a computer-readable storage medium. Background Art

[0003] As an indispensable component of the power system, the energy storage system can provide the system with a series of inertia, frequency, voltage, reactive power and damping support. As a new type of energy storage topology, high-voltage direct-mounted energy storage can realize the design of large capacity and large voltage level. Typical topologies commonly used for high-voltage direct-mounted energy storage include MMC (Modular Multilevel Converter) type energy storage, H-bridge cascade topology and other forms. Among them, the modular multilevel converter topology has high output power quality and has received widespread attention. However, the requirements for the DC voltage of the energy storage device based on the modular multilevel converter topology are different in different application scenarios. In the related art, the battery in the energy storage device based on the modular multilevel converter topology is set in the modular multilevel converter sub-module. If you want to change the DC voltage to adapt to different application scenarios, you need to redesign the energy storage device. The design process is relatively complicated and lengthy, and the design efficiency is low. Summary of the Invention

[0004] The purpose of this application is to provide an energy storage device, a design method for an energy storage device, and a computer-readable storage medium, which can reduce the design complexity of the energy storage device under different voltage requirements and improve the design efficiency of the energy storage device.

[0005] In a first aspect, an embodiment of the present application provides an energy storage device, comprising: a DC energy storage valve, comprising energy storage modules connected in series, the energy storage modules comprising a power module and an energy storage unit, the DC energy storage valve being configured to provide a DC voltage; a three-phase modular multilevel converter circuit having a DC side connected to both ends of the DC energy storage valve, the three-phase modular multilevel converter circuit comprising two or more modular multilevel converter submodules, each of the modular multilevel converter submodules being a full-bridge submodule or a half-bridge submodule, and the proportion of the full-bridge submodules in the two or more modular multilevel converter submodules being determined based on a target regulation range of the DC voltage.

[0006] Compared with the related art, in the energy storage device provided in the embodiment of the present application, the number and proportion of full-bridge sub-modules in the three-phase modular multi-level converter circuit are determined according to the target adjustment range of the DC voltage. The target adjustment range can be flexibly set according to different actual needs. Therefore, when designing an energy storage device for different voltage requirements, it is only necessary to set full-bridge sub-modules with different numbers and proportions according to different voltage requirements, thereby reducing the design complexity of the energy storage device under different voltage requirements and improving the design efficiency of the energy storage device; in addition, compared with the half-bridge sub-module, the full-bridge sub-module has higher structural stability. Therefore, setting a full-bridge sub-module in the three-phase modular multi-level converter circuit can improve the overall stability of the energy storage device.

[0007] In an optional embodiment, the number of the three-phase modular multilevel converter circuits is N, where N is a positive integer greater than 1, and the N three-phase modular multilevel converter circuits are connected in parallel at both ends of the DC energy storage valve; the number of the full-bridge sub-modules in the N three-phase modular multilevel converter circuits has a different proportion; or, the number of the full-bridge sub-modules in M ​​of the N three-phase modular multilevel converter circuits has the same proportion, and M is a positive integer less than or equal to N. By providing N three-phase modular multilevel converter circuits, when the proportions of the full-bridge sub-modules in the N three-phase modular multilevel converter circuits are different, the circuits can simultaneously adapt to a variety of different voltage requirements, reducing the need to redesign the circuit when the voltage requirement changes. When the proportions of the full-bridge sub-modules in M ​​three-phase modular multilevel converter circuits are the same among the N three-phase modular multilevel converter circuits, the three-phase modular multilevel converter circuits with the same proportions of the full-bridge sub-modules can meet the same voltage requirement, enabling the parallel use of the M three-phase modular multilevel converter circuits and improving the fault resistance of the energy storage device.

[0008] In an optional embodiment, the three-phase modular multilevel converter circuit includes two or more modular multilevel converter bridge arms, each of which includes two or more modular multilevel converter submodules; each modular multilevel converter bridge arm includes both the full-bridge submodule and the half-bridge submodule; or some of the modular multilevel converter bridge arms include only the full-bridge submodule; or some of the modular multilevel converter bridge arms include only the half-bridge submodule. By providing a DC energy storage valve, the energy storage unit is transferred to the energy storage module of the DC energy storage valve. The number and location of the full-bridge submodules and half-bridge submodules in the modular multilevel converter bridge arm can be flexibly set according to actual voltage requirements, DC short-circuit fault isolation requirements, cost, and other factors. For example, each modular multilevel converter bridge arm can be configured to include both the full-bridge submodule and the half-bridge submodule; or some of the modular multilevel converter bridge arms include only the full-bridge submodule; or some of the modular multilevel converter bridge arms include only the half-bridge submodule, thereby increasing the scope of application.

[0009] In an optional embodiment, the number of full-bridge sub-modules in the two or more modular multilevel converter bridge arms is the same. Because the number of full-bridge sub-modules in the two or more modular multilevel converter bridge arms is the same, their control logic is also the same, allowing for unified control of the two or more modular multilevel converter bridge arms, simplifying the control process while improving control efficiency.

[0010] In an optional embodiment, there are two or more DC energy storage valves, which are connected in parallel. Multiple DC energy storage valves are connected in parallel. While maintaining the energy storage capacity of the energy storage device and the total number of battery modules used is the same, the number of energy storage modules in each DC energy storage valve is set according to the actual voltage level requirements of the energy storage device. Alternatively, while ensuring that the actual voltage level of the energy storage device remains unchanged, the number of DC energy storage valves can be set according to the actual energy storage capacity requirements, thereby expanding the application range of the energy storage device.

[0011] In a second aspect, an embodiment of the present application provides a design method for an energy storage device, which is used to design an energy storage device as described above. The design method for the energy storage device includes: obtaining a target adjustment range of the DC voltage of the energy storage device, the target adjustment range including a lower voltage limit and an upper voltage limit; determining the proportion of the number of full-bridge sub-modules of the three-phase modular multi-level converter circuit in the energy storage device based on the voltage ratio of the lower voltage limit to the upper voltage limit; and determining the number of energy storage modules in the DC energy storage valve based on the upper voltage limit.

[0012] Compared with related technologies, in the design method for an energy storage device provided in the embodiments of the present application, different voltage requirements correspond to different target regulation ranges. When designing the energy storage device for different target regulation ranges, the number and proportion of full-bridge sub-modules of the three-phase modular multi-level converter circuit in the energy storage device is directly determined based on the voltage ratio between the lower voltage limit and the upper voltage limit in the target regulation range. This eliminates the need to change the overall structure of the energy storage device, thereby reducing the design complexity of the energy storage device under different voltage requirements and improving the design efficiency of the energy storage device.

[0013] In an optional embodiment, determining the quantity ratio of full-bridge submodules in the three-phase modular multilevel converter circuit of the energy storage device based on the voltage ratio between the lower voltage limit and the upper voltage limit includes: providing a preset correspondence list, the preset correspondence list including a one-to-one correspondence between two or more preset voltage ratios and two or more preset quantity ratios; and determining the quantity ratio of the full-bridge submodules based on the preset correspondence list and the voltage ratios. For different target adjustment ranges, determining the quantity ratio of the full-bridge submodules via a table lookup eliminates the need for complex data or model training, reduces costs, and improves the efficiency of determining the quantity ratio.

[0014] In an optional embodiment, determining the number of energy storage modules in the DC energy storage valve based on the voltage upper limit includes: obtaining a submodule voltage of the energy storage module; and determining the number of energy storage modules in each DC energy storage valve in the energy storage device based on the voltage upper limit and the submodule voltage. Determining the number of energy storage modules in each DC energy storage valve based on the voltage upper limit and the submodule voltage can reduce the occurrence of situations where the DC voltage of the energy storage device cannot meet the voltage upper limit requirement.

[0015] In an optional embodiment, the energy storage device design method further includes determining the capacitance value of a submodule capacitor in the energy storage module based on the submodule voltage. The capacitance value of the submodule capacitor is determined based on the voltage level of the energy storage device and the proportion of full-bridge submodules corresponding to actual usage, so that the capacitance value of the submodule capacitor better meets actual needs and better controls costs while ensuring the safety of the submodule capacitor.

[0016] In an optional embodiment, the energy storage device design method further includes: obtaining a target energy storage capacity of the energy storage device; determining the number of energy storage units in each energy storage module in parallel based on the target energy storage capacity and the number of energy storage modules in each DC energy storage valve; or determining the number of DC energy storage valves in parallel based on the target energy storage capacity and the number of energy storage modules in each DC energy storage valve. By determining the number of battery modules in parallel or the number of DC energy storage valves in parallel in each energy storage module based on the target energy storage capacity, the battery modules can be flexibly designed according to the target energy storage capacity while maintaining the voltage level of the energy storage device unchanged.

[0017] In a third aspect, an embodiment of the present application provides an electronic device comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the design method of the energy storage device as described above.

[0018] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium storing a computer program, wherein the computer program is executed by a processor to implement the aforementioned method for designing an energy storage device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can also be obtained based on these drawings.

[0020] FIG1 is a schematic structural diagram of a modular multilevel converter topology provided in an embodiment of the present application;

[0021] FIG2 is a schematic diagram of the circuit structure of a half-bridge submodule provided in an embodiment of the present application;

[0022] FIG3 is a schematic diagram of the circuit structure of the full-bridge submodule provided in an embodiment of the present application;

[0023] FIG4 is a schematic diagram of a circuit structure in which an energy storage unit is provided in a half-bridge submodule in the related art;

[0024] FIG5 is a schematic diagram of a circuit structure in which an energy storage unit is provided in a full-bridge submodule in the related art;

[0025] FIG6 is a schematic structural diagram of an energy storage device provided in an embodiment of the present application;

[0026] FIG7 is a schematic structural diagram of an energy storage device provided in another embodiment of the present application;

[0027] FIG8 is a schematic structural diagram of an energy storage module in some embodiments of the present application;

[0028] FIG9 is a schematic diagram of a circuit structure of a connection between a half-bridge submodule and an energy storage unit in some embodiments of the present application;

[0029] FIG10 is a schematic diagram of a circuit structure of a connection between a full-bridge submodule and an energy storage unit in some embodiments of the present application;

[0030] FIG11 is a flow chart of a method for designing an energy storage device according to an embodiment of the present application;

[0031] FIG12 is a graph showing a function of the ratio of the number of full-bridge submodules and the voltage ratio in the design method of an energy storage device provided by one embodiment of the present application;

[0032] FIG13 is a schematic diagram of a flow chart of determining the number of energy storage modules in a DC energy storage valve according to a voltage upper limit in a design method for an energy storage device provided by an embodiment of the present application;

[0033] FIG14 is a flow chart of a method for designing an energy storage device according to another embodiment of the present application;

[0034] FIG15 is a flow chart of a method for designing an energy storage device according to another embodiment of the present application;

[0035] FIG16 is a schematic structural diagram of an electronic device provided in another embodiment of the present application. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described in detail below with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the application as claimed, but is merely representative of selected embodiments of the present application.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0039] In addition, the terms "first", "second", etc., if used, are merely used to distinguish and describe, and should not be understood as indicating or implying relative importance.

[0040] It should be noted that, in the absence of conflict, the features in the embodiments of this application can be combined with each other.

[0041] With the increasing prevalence of distributed renewable energy grid-connected power generation, the proportion of distributed generation capacity in the overall power system will continue to grow. However, various distributed generation technologies, such as wind and solar power, are intermittent energy sources, severely affected by climate and environmental factors, and their output power is unstable and not fully controllable. In this environment, the deployment of large-scale distributed grid-connected devices will significantly improve the power quality, stability, and safe operation of the power system. The connection of distributed generation systems to the grid requires the configuration of energy storage systems of a certain capacity to ensure the continuity and reliability of their power supply. Typical topologies for high-voltage direct-mounted energy storage include MMC (Modular Multilevel Converter) energy storage and H-bridge cascade topologies. The modular multilevel converter topology, with its high output power quality, has attracted widespread attention.

[0042] Please refer to Figure 1. As shown in Figure 1, the modular multilevel converter topology provided in an embodiment of the present application is composed of six bridge arms, each of which has a large number of submodules (SM) connected in series. The main components of the submodule are high-voltage DC capacitors, semiconductor switching devices, and diodes. Typical submodule structures include full-bridge and half-bridge structures. The submodule with a half-bridge structure is usually called a half-bridge submodule, and the submodule with a full-bridge structure is usually called a full-bridge submodule.

[0043] Please refer to Figure 2, which is a schematic diagram of the circuit structure of the half-bridge submodule provided in an embodiment of the present application. As shown in Figure 2, the half-bridge submodule includes: a first insulated gate transistor T1, a second insulated gate transistor T2, a first diode D1, a second diode D2, and a submodule capacitor C. Among them, the emitter of the first insulated gate transistor T1 is connected to the input end of the first diode D1, and the collector of the first insulated gate transistor T1 is connected to the output end of the first diode D1; the emitter of the second insulated gate transistor T2 is connected to the input end of the second diode D2, and the collector of the second insulated gate transistor T2 is connected to the output end of the second diode D2; the submodule capacitor C is connected between the collector of the first insulated gate transistor T1 and the emitter of the second insulated gate transistor T2; a first connection terminal A is provided between the emitter of the first insulated gate transistor T1 and the collector of the second insulated gate transistor T2; and a second connection terminal B is provided at the emitter of the second insulated gate transistor T2.

[0044] Please refer to Figure 3, which is a schematic diagram of the circuit structure of the full-bridge submodule provided in an embodiment of the present application. As shown in Figure 3, the full-bridge submodule includes: a third insulated gate transistor T3, a fourth insulated gate transistor T4, a fifth insulated gate transistor T5, a sixth insulated gate transistor T6, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6 and a submodule capacitor C; the emitter of the third insulated gate transistor T3 is connected to the input end of the third diode D3, and the collector of the third insulated gate transistor T3 is connected to the output end of the third diode D3; the emitter of the fourth insulated gate transistor T4 is connected to the input end of the fourth diode D4, and the collector of the fourth insulated gate transistor T4 is connected to the output end of the fourth diode D4; the emitter of the fifth insulated gate transistor T5 is connected to the input end of the fifth diode D5, and the collector of the fifth insulated gate transistor T5 is connected to the output end of the third diode D3; The output end of the fifth diode D5 is connected; the emitter of the sixth insulated gate transistor T6 is connected to the input end of the sixth diode D6, and the collector of the sixth insulated gate transistor T6 is connected to the output end of the sixth diode D6; the sub-module capacitor C is connected between the collector of the third insulated gate transistor T3 and the emitter of the fourth insulated gate transistor T4, the collector of the fifth insulated gate transistor T5 is connected to the collector of the third insulated gate transistor T3, and the emitter of the sixth insulated gate transistor T6 is connected to the emitter of the fourth insulated gate transistor T4; a first connection terminal A is provided between the emitter of the third insulated gate transistor T3 and the collector of the fourth insulated gate transistor T4, and a second connection terminal B is provided between the emitter of the fifth insulated gate transistor T5 and the collector of the sixth insulated gate transistor T6.

[0045] In the related art, please refer to Figures 4 and 5. Figure 4 shows a schematic diagram of the circuit structure of the energy storage unit provided in the half-bridge submodule in the related art, and Figure 5 shows a schematic diagram of the circuit structure of the energy storage unit provided in the full-bridge submodule in the related art. Because the energy storage unit of this modular multi-level converter-type energy storage device is included in each submodule of the modular multi-level converter, if the demand for DC voltage changes during application, if the DC voltage is to be changed to adapt to different application scenarios, the energy storage device needs to be redesigned, which results in a complex and lengthy design process and low design efficiency.

[0046] To solve the above technical problems, the embodiments of the present application provide an energy storage device, a design method for an energy storage device, and a computer-readable storage medium. A DC energy storage valve is provided in the energy storage device to provide a DC voltage, and a three-phase modular multilevel converter circuit is provided to be connected to the DC energy storage valve. The modular multilevel converter submodule in the three-phase modular multilevel converter circuit is a full-bridge submodule or a half-bridge submodule. At the same time, the number and proportion of full-bridge submodules in two or more modular multilevel converter submodules can be determined according to the target adjustment range of the DC voltage. The target adjustment range can be flexibly set according to different actual needs. Therefore, when designing an energy storage device for different voltage requirements, it is only necessary to set different numbers and proportions of full-bridge submodules according to different voltage requirements, thereby reducing the design complexity of the energy storage device under different voltage requirements and improving the design efficiency of the energy storage device.

[0047] It is understandable that the energy storage device, energy storage device design method, and computer-readable storage medium disclosed in the embodiments of the present application can be applied to various forms of electric energy storage scenarios, including but not limited to electric vehicle charging stations, wind power stations, solar power stations, etc.

[0048] Referring to FIG6 , an embodiment of the present application provides an energy storage device 100, which includes a DC energy storage valve 101 and a three-phase modular multilevel converter circuit 102 connected to both ends of the DC energy storage valve 101. The DC energy storage valve 101 includes an energy storage module 103 connected in series, which includes a power module 1031 and an energy storage unit 1032. The three-phase modular multilevel converter circuit 102 includes two or more modular multilevel converter submodules 108, each of which is a full-bridge submodule or a half-bridge submodule. The proportion of full-bridge submodules in the two or more modular multilevel converter submodules 108 is determined based on the target regulation range of the DC voltage.

[0049] The target adjustment range is a range of DC voltages pre-set based on actual needs. Energy storage devices in related technologies experience significant damage when operating under conditions where the DC voltage is lower than their upper voltage limit, making them difficult to operate stably for a long period of time. The energy storage device provided in the embodiments of the present application, by configuring at least some of the modular multilevel converter submodules 108 as full-bridge submodules, can improve the stability of the energy storage device when operating under conditions where the DC voltage is lower than its upper voltage limit. Furthermore, different ratios of full-bridge submodules can achieve different levels of step-down operation. Determining the ratio of full-bridge submodules based on the target DC voltage adjustment range can better meet actual application needs.

[0050] Specifically, as shown in FIG6 , the DC energy storage valve 101 includes two or more energy storage modules 103 , each of which includes a power module 1031 and an energy storage unit 1032 . The power module 1031 is a half-bridge submodule as shown in FIG2 or a full-bridge submodule as shown in FIG3 . As shown in FIG2 and FIG3 , the power module 1031 includes a first connection terminal A, a second connection terminal B, and a submodule capacitor C. In the DC energy storage valve 101 , the two or more energy storage modules 103 are interconnected. For example, the first connection terminal A of the previous energy storage module 103 may be connected to the second connection terminal B of the next energy storage module 103 . The two or more energy storage modules 103 are sequentially connected to form the energy storage module 103 . In each energy storage module 103 , the positive and negative electrodes of the energy storage unit 1032 are respectively connected to the two ends of the submodule capacitor C. The DC port of each modular multilevel converter bridge arm 107 is respectively connected to the first connection terminal A or the second connection terminal B at the two ends of the DC energy storage valve 101 . That is, the DC ports of some modular multilevel converter bridge arms 107 are connected to the first connection terminals A at both ends of the DC energy storage valve 101 , and the DC ports of another part of the modular multilevel converter bridge arms 107 are connected to the second connection terminals B at both ends of the DC energy storage valve 101 .

[0051] In some embodiments of the present application, the energy storage unit is a multi-battery structure composed of two or more connected batteries, each of which may include two or more battery cells. The battery cells can convert the electrical energy of the external power supply into chemical energy or other forms of energy for storage when the external power supply is charged, and convert the stored chemical energy or other forms of energy into electrical energy for output to the external appliance when the external power supply is connected.

[0052] In some embodiments of the present application, as shown in FIG6 , the DC energy storage valve 101 may further include an isolation switch 104, a starting resistor 105, an energy storage device reactor 106, and other structures. The isolation switch 104 is used to connect and / or disconnect the DC energy storage valve 101 from the external circuit, the starting resistor 105 is used to perform a partial energy storage function at the beginning of charging, and transfer the stored energy to the energy storage module 103 during the subsequent charging process, and the energy storage device reactor 106 is used to protect the DC energy storage valve 101.

[0053] By providing a DC energy storage valve and placing the battery sub-module in the DC energy storage valve to achieve energy storage, compared to the structure of placing the battery module in the bridge arm of the modular multi-level converter in the related art, placing the battery sub-module in the DC energy storage valve can improve the integration of the energy storage system and increase the utilization rate of the battery module at the same time. Therefore, under the condition of the same energy storage capacity, the energy storage device provided by the embodiment of the present application has fewer batteries.

[0054] In some embodiments of the present application, the power modules in two or more energy storage modules are all half-bridge sub-modules.

[0055] It is understandable that the power modules in two or more energy storage modules are all half-bridge submodules, which is only an example of maximizing cost savings in some embodiments of the present application. In some other embodiments of the present application, it is also possible to select the power modules in some energy storage modules as full-bridge submodules based on the requirements for the steady-state value of the voltage level of the energy storage device of the energy storage module, or to select the power modules in all energy storage modules as full-bridge submodules or other structures. The voltage level of the energy storage device is the main line voltage of the energy storage device. In the embodiment of the present application, the voltage level of the energy storage device is equal to the sum of the voltages of the individual energy storage modules in the DC energy storage valve.

[0056] Compared with full-bridge submodules, half-bridge submodules have lower costs. Setting the power modules in two or more energy storage modules to be half-bridge submodules can effectively reduce the cost of the energy storage device.

[0057] Compared with related art, in the energy storage device provided in the embodiment of the present application, the number and proportion of full-bridge submodules in all modular multilevel converter submodules 108 in the three-phase modular multilevel converter circuit are determined according to the target adjustment range of the DC voltage. The target adjustment range can be flexibly set according to different actual needs. Therefore, when designing the energy storage device for different voltage requirements, it is only necessary to set different numbers and proportions of full-bridge submodules according to the different voltage requirements, thereby reducing the design complexity of the energy storage device under different voltage requirements and improving the design efficiency of the energy storage device.

[0058] In some embodiments of the present application, the number of three-phase modular multilevel converter circuits is N, where N is a positive integer greater than 1, and the N three-phase modular multilevel converter circuits are connected in parallel at both ends of the DC energy storage valve; the number of the full-bridge sub-modules in the two or more three-phase modular multilevel converter circuits is different; or, the number of the full-bridge sub-modules in the two or more three-phase modular multilevel converter circuits is the same.

[0059] Specifically, as shown in Figure 7, the DC energy storage valve can be connected to two three-phase modular multilevel converter circuits, each of which has its own independent three-phase port. Depending on the usage scenario, the three-phase ports of the two three-phase modular multilevel converter circuits can be used for independent charging and discharging.

[0060] It will be understood that FIG7 is merely an example of some embodiments of the present application in which two three-phase modular multilevel converter circuits are provided. In some other embodiments of the present application, three or even more three-phase modular multilevel converter circuits may be provided, and the specific configuration may be based on actual needs.

[0061] Furthermore, in an embodiment in which two or more three-phase modular multilevel converter circuits are provided, the proportions of the number of full-bridge sub-modules in all three-phase modular multilevel converter circuits may be different, or the proportions of the number of full-bridge sub-modules in all three-phase modular multilevel converter circuits may be the same, or the proportions of the number of full-bridge sub-modules in some three-phase modular multilevel converter circuits may be the same, and the proportions of the number of full-bridge sub-modules in some three-phase modular multilevel converter circuits may be different. The specific configuration may be made according to actual needs.

[0062] N three-phase modular multilevel converter circuits are provided. When the proportions of the full-bridge sub-modules in all the N three-phase modular multilevel converter circuits are different, a variety of different voltage requirements can be simultaneously adapted, reducing the need to redesign the circuit when the voltage requirement changes. When the proportions of the full-bridge sub-modules in M ​​three-phase modular multilevel converter circuits are the same among the N three-phase modular multilevel converter circuits, that is, when the proportions of the full-bridge sub-modules in all or part of the three-phase modular multilevel converter circuits are the same, the three-phase modular multilevel converter circuits with the same proportions of the full-bridge sub-modules can meet the same voltage requirement, thereby enabling the interchangeable use of the M three-phase modular multilevel converter circuits and improving the fault resistance of the energy storage device.

[0063] In some embodiments of the present application, the three-phase modular multilevel converter circuit includes two or more modular multilevel converter bridge arms, each of the modular multilevel converter bridge arms includes two or more modular multilevel converter sub-modules; each of the modular multilevel converter bridge arms includes the full-bridge sub-module and the half-bridge sub-module; or some of the modular multilevel converter bridge arms only include the full-bridge sub-module; or some of the modular multilevel converter bridge arms only include the half-bridge sub-module.

[0064] Specifically, the three-phase modular multilevel converter circuit includes two or more modular multilevel converter bridge arms 107. As shown in FIG6 , the three-phase modular multilevel converter circuit 102 may be, for example, a modular multilevel converter circuit with a three-phase six-bridge-arm structure, including two or more modular multilevel converter bridge arms 107. Each modular multilevel converter bridge arm 107 includes a DC port K and a three-phase port (the three ports U, V, and W in FIG6 together constitute a three-phase port). The DC port of each modular multilevel converter bridge arm 107 is respectively connected to the DC energy storage valve 101.

[0065] In some embodiments of the present application, as shown in FIG6 , each modular multilevel converter bridge arm 107 of the three-phase modular multilevel converter circuit 102 is provided with two or more modular multilevel converter submodules 108 , wherein each modular multilevel converter submodule 108 can be a full-bridge submodule or a half-bridge submodule. In an actual energy storage device, the modular multilevel converter submodules 108 on the modular multilevel converter bridge arms 107 can be configured such that each modular multilevel converter bridge arm 107 includes both a full-bridge submodule and a half-bridge submodule; or some modular multilevel converter bridge arms 107 include only full-bridge submodules; or some modular multilevel converter bridge arms 107 include only half-bridge submodules. That is, in different embodiments of the present application, the number and location of the half-bridge submodules and the full-bridge submodules on the modular multilevel converter bridge arms 107 can be flexibly configured based on actual requirements such as voltage requirements, DC short-circuit fault isolation requirements, and cost requirements. Specifically, the ratio of the number of full-bridge sub-modules in the two or more modular multi-level converter sub-modules 108 is determined according to the target adjustment range of the DC voltage.

[0066] Since the energy storage unit 1032 is transferred to the energy storage module 103 of the DC energy storage valve 101, the number and arrangement positions of the full-bridge sub-modules and half-bridge sub-modules in each modular multilevel converter bridge arm 107 can be flexibly arranged according to actual voltage requirements, DC short-circuit fault isolation requirements, cost, and other factors. For example, it can be arranged that each modular multilevel converter bridge arm includes a full-bridge sub-module and a half-bridge sub-module; or some modular multilevel converter bridge arms include only full-bridge sub-modules; or some modular multilevel converter bridge arms include only half-bridge sub-modules, thereby improving the scope of application.

[0067] In some embodiments of the present application, the number of the full-bridge sub-modules in two or more modular multi-level converter bridge arms is the same.

[0068] Specifically, each modular multilevel converter bridge arm is provided with a full-bridge sub-module. In each modular multilevel converter bridge arm, the ratio of the number of full-bridge sub-modules to the number of all sub-modules is the proportion of the number of full-bridge sub-modules in the modular multilevel converter bridge arm.

[0069] Furthermore, in some other embodiments of the present application, the proportion of the number of the full-bridge sub-modules in some modular multilevel converter bridge arms in all modular multilevel converter bridge arms may be the same, and the proportion of the number of the full-bridge sub-modules in some modular multilevel converter bridge arms may be different.

[0070] Furthermore, in some other embodiments of the present application, the proportion of the number of full-bridge sub-modules in each modular multilevel converter bridge arm in different three-phase modular multilevel converter circuits may also be the same.

[0071] The number of full-bridge sub-modules in two or more modular multilevel converter bridge arms is the same, so their control logic is also the same, so that the two or more modular multilevel converter bridge arms can be controlled uniformly, simplifying the control process while improving control efficiency.

[0072] In some embodiments of the present application, the number of DC energy storage valves in the energy storage device is two or more, and the two or more DC energy storage valves are connected in parallel.

[0073] The number of energy storage modules in two or more DC energy storage valves may be equal or different, and may be flexibly set according to the actual voltage level requirements of the energy storage device.

[0074] Two or more DC energy storage valves are connected in parallel, that is, two or more first connection ends at both ends of the two or more DC energy storage valves are connected to the same point, and two or more second connection ends at both ends of the two or more DC energy storage valves are connected to the same point.

[0075] Two or more DC energy storage valves are connected in parallel. While keeping the energy storage capacity of the energy storage device unchanged and the total number of battery modules used equal, the number of energy storage modules in each DC energy storage valve is set according to the actual voltage level requirements of the energy storage device.

[0076] In some embodiments of the present application, please refer to Figure 8, which is a structural schematic diagram of the energy storage module in some embodiments of the present application. As shown in Figure 8, each energy storage module can also include two or more energy storage units, and the two or more energy storage units are connected in parallel.

[0077] As shown in FIG8 , two or more energy storage units may be connected in parallel by connecting two or more positive electrodes of the two or more energy storage units to one end of the submodule capacitor, and connecting two or more negative electrodes of the two or more energy storage units to the other end of the submodule capacitor.

[0078] Two or more battery modules are connected in parallel. While keeping the energy storage capacity of the energy storage device unchanged and the total number of energy storage units used equal, the number of energy storage units in each energy storage module is set according to the actual voltage level requirements of the energy storage device; or while ensuring that the actual voltage level of the energy storage device remains unchanged, the energy storage units in each energy storage module can be set according to the energy storage capacity requirements at the time, thereby improving the actual application range of the energy storage device.

[0079] Further, please refer to Figure 9, which shows a schematic diagram of the circuit structure of the connection between the half-bridge sub-module and the energy storage unit in some embodiments of the present application. As shown in Figure 9, the positive and negative electrodes of the energy storage unit 1032 are connected to the two ends of the sub-module capacitor C in the half-bridge sub-module.

[0080] Only the first insulated gate transistor T1 , the second insulated gate transistor T2 , the first diode D1 , the second diode D2 and the submodule capacitor C are provided in the half-bridge submodule, which can effectively reduce the manufacturing cost of the power module.

[0081] In some embodiments of the present application, please refer to FIG3 , which is a schematic diagram of the circuit structure of a full-bridge submodule. As shown in FIG3 , the full-bridge submodule includes: a third insulated gate transistor T3, a fourth insulated gate transistor T4, a fifth insulated gate transistor T5, a sixth insulated gate transistor T6, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, and a submodule capacitor C. The specific connection relationship can be referred to the detailed description of FIG3 above and will not be repeated here.

[0082] Further, please refer to Figure 10, which shows a schematic diagram of the circuit structure of the connection between the full-bridge submodule and the energy storage unit in some embodiments of the present application. As shown in Figure 10, the positive and negative electrodes of the energy storage unit 1032 are connected to the two ends of the submodule capacitor C in the full-bridge submodule.

[0083] A third insulated gate transistor T3, a fourth insulated gate transistor T4, a fifth insulated gate transistor T5, a sixth insulated gate transistor T6, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6 and a submodule capacitor C are provided in the full-bridge submodule, which can achieve a better isolation effect for branch short-circuit faults.

[0084] Furthermore, in the energy storage device provided in the embodiment of the present application, regardless of whether the power module is configured as a half-bridge submodule or a full-bridge submodule, the power module can flexibly adjust the access state of each energy storage module in the overall circuit of the DC energy storage valve according to actual needs, thereby achieving constant current / constant voltage control.

[0085] The present application also provides a method for designing an energy storage device, which is used to configure an energy storage device having a structure as in the above-mentioned embodiment. As shown in FIG11 , the method for designing an energy storage device includes:

[0086] Step S101: obtaining a target regulation range of a DC voltage of an energy storage device, where the target regulation range includes a lower voltage limit and an upper voltage limit.

[0087] Step S102: determining a ratio of the number of full-bridge submodules of the three-phase modular multi-level converter circuit in the energy storage device according to a voltage ratio between a lower voltage limit and an upper voltage limit.

[0088] Step S103: determining the number of energy storage modules in the DC energy storage valve according to the voltage upper limit.

[0089] It will be understood that the energy storage device in the energy storage device design method provided in this embodiment is the energy storage device provided in the aforementioned embodiment. The energy storage device design method provided in this embodiment is used to determine other parameters of the energy storage device based on the requirements of the energy storage device. Specifically, after determining the target adjustment range of the energy storage device based on actual requirements, the number ratio of full-bridge sub-modules of the three-phase modular multi-level converter circuit in the energy storage device is determined based on the voltage ratio of the voltage lower limit to the voltage upper limit in the target adjustment range. The design of the energy storage device can be completed by setting a corresponding number of full-bridge sub-modules based on the number ratio.

[0090] Compared with related technologies, in the design method for an energy storage device provided in the embodiments of the present application, corresponding target adjustment ranges can be pre-set for different voltage requirements. When designing the energy storage device for different target adjustment ranges, the number and proportion of full-bridge sub-modules of the three-phase modular multi-level converter circuit in the energy storage device are directly determined based on the voltage ratio between the lower voltage limit and the upper voltage limit in the target adjustment range. This eliminates the need to change the overall structure of the energy storage device, thereby reducing the design complexity of the energy storage device under different voltage requirements and improving the design efficiency of the energy storage device.

[0091] In some embodiments of the present application, determining the quantity ratio of the full-bridge sub-modules of the three-phase modular multi-level converter circuit in the energy storage device according to the voltage ratio of the voltage lower limit to the voltage upper limit in step S102 can specifically be: providing a preset corresponding list, the preset corresponding list including a one-to-one correspondence between two or more preset voltage ratios and two or more preset quantity ratios; and determining the quantity ratio of the full-bridge sub-modules according to the preset corresponding list and the voltage ratio.

[0092] Specifically, the preset corresponding list is a list formed by pre-stored one-to-one correspondence between preset voltage ratios and elements and quantity ratios. Specifically, it can be shown in the following table, including:

[0093] It is understandable that the above table only illustrates some of the corresponding relationships and does not constitute a limitation. In actual application, more corresponding relationships may be set.

[0094] It can be understood that determining the proportion of the number of full-bridge sub-modules based on the preset corresponding list and voltage ratio is only an example in some embodiments of the present application. In some other embodiments of the present application, other schemes such as determining the proportion of the number of full-bridge sub-modules based on the function image and voltage ratio as shown in Figure 12 can also be used.

[0095] For different target adjustment ranges, the quantity ratio of the full-bridge sub-modules is determined by a table lookup method, without the need for complex data or model training. This is low-cost and can also improve the efficiency of determining the quantity ratio.

[0096] In some embodiments of the present application, as shown in FIG13 , determining the number of energy storage modules in the DC energy storage valve according to the voltage upper limit in step S103 may specifically include:

[0097] Step S201: Obtain the submodule voltage of the energy storage module.

[0098] Step S202: determining the number of energy storage modules in each DC energy storage valve in the energy storage device according to the voltage upper limit and the submodule voltage.

[0099] Specifically, a single energy storage unit includes two or more batteries, and a single battery includes two or more cells. The battery parameters of the energy storage unit include the number of batteries in the energy storage unit, the number of cells in each battery, the cell capacity of each cell, the nominal operating voltage of the cell, and the minimum operating voltage of the cell. The submodule voltage of the energy storage unit can be obtained by multiplying the number of batteries in the energy storage unit, the number of cells in each battery, and the minimum operating voltage of each cell. For example, taking a single energy storage unit including 12 batteries, a single battery including 52 cells in series, and a nominal operating voltage of a single cell of 3.2V and a minimum operating voltage of 2.8V as an example, the submodule voltage of the energy storage unit is 52×12×2.8V=1747.2V.

[0100] Determining the number of energy storage modules in each DC energy storage valve in the energy storage device based on the upper voltage limit and the submodule voltage can specifically be done by rounding the quotient of the upper voltage limit and the submodule voltage of the energy storage unit as the number of energy storage modules in each DC energy storage valve. For example, if the upper voltage limit of the energy storage device is ±20 kV, the number of energy storage modules in each DC energy storage valve is 20 kV × 2 ÷ 1747.2 V = 22.89, which is rounded to 23, indicating that each DC energy storage valve has 23 energy storage modules.

[0101] Determining the number of energy storage modules in each DC energy storage valve based on the voltage upper limit and the submodule voltage can reduce the occurrence of situations where the DC voltage of the energy storage device cannot meet the voltage upper limit requirement.

[0102] In some embodiments of the present application, as shown in FIG14 , the design method of the energy storage device may specifically include:

[0103] Step S101: obtaining a target regulation range of a DC voltage of an energy storage device, where the target regulation range includes a lower voltage limit and an upper voltage limit.

[0104] Step S102: determining a ratio of the number of full-bridge submodules of the three-phase modular multi-level converter circuit in the energy storage device according to a voltage ratio between a lower voltage limit and an upper voltage limit.

[0105] Step S103: obtaining the submodule voltage of the energy storage unit, and determining the number of energy storage modules in each DC energy storage valve in the energy storage device according to the voltage upper limit and the submodule voltage.

[0106] Step S104: determining the capacitance value of the submodule capacitor in the energy storage module according to the submodule voltage.

[0107] Specifically, determining the capacitance value of the submodule capacitor according to the voltage level of the energy storage device and the proportion of the number of full-bridge submodules in step S104 may be: finally determining the capacitance value of the submodule capacitor based on the determined submodule voltage, investment cost and other factors.

[0108] The capacitance value of the submodule capacitor is determined according to the voltage level of the energy storage device and the proportion of the number of full-bridge submodules corresponding to actual usage, so that the capacitance value of the submodule capacitor is more in line with actual needs and the cost is better controlled under the premise of ensuring the safety of the submodule capacitor.

[0109] In some embodiments of the present application, as shown in FIG15 , the design method of the energy storage device may specifically include:

[0110] Step S101: obtaining a target adjustment range of a DC voltage of an energy storage device, where the target adjustment range includes a lower voltage limit and an upper voltage limit.

[0111] Step S102: determining a ratio of the number of full-bridge submodules of the three-phase modular multi-level converter circuit in the energy storage device according to a voltage ratio between a lower voltage limit and an upper voltage limit.

[0112] Step S103: obtaining the submodule voltage of the energy storage unit, and determining the number of energy storage modules in each DC energy storage valve in the energy storage device according to the voltage upper limit and the submodule voltage.

[0113] Step S104: determining the capacitance value of the submodule capacitor in the energy storage module according to the submodule voltage.

[0114] Step S105: Obtain a target energy storage capacity of the energy storage device, and determine the number of energy storage units in each energy storage module connected in parallel based on the target energy storage capacity and the number of energy storage modules in each DC energy storage valve; alternatively, determine the number of DC energy storage valves connected in parallel based on the target energy storage capacity and the number of energy storage modules in each DC energy storage valve.

[0115] The rounded value of the quotient of the target energy storage capacity, the number of energy storage modules in each DC energy storage valve, and the energy storage capacity of each energy storage unit can be used as the number of energy storage units connected in parallel in each energy storage module or the number of DC energy storage valves connected in parallel. For example, if the number of energy storage modules in each DC energy storage valve is 23, the target energy storage capacity is 90 MWh, a single energy storage unit includes 12 batteries, a single battery includes 52 cells connected in series, and the cell capacity of a single cell is 280 Ah, then the rounded value of (90 MWh ÷ 23) ÷ (52 × 12 × 3.2 V × 280 Ah × 23) = 6.998, which is 7, can be used as the number of energy storage units connected in parallel in each energy storage module or the number of DC energy storage valves connected in parallel.

[0116] The number of energy storage units in each energy storage module connected in parallel or the number of DC energy storage valves connected in parallel is determined according to the target energy storage capacity. The energy storage units can be flexibly designed according to the target energy storage capacity while maintaining the voltage level of the energy storage device unchanged.

[0117] An embodiment of the present application also relates to an electronic device, as shown in Figure 16, comprising: at least one processor 201; and a memory 202 communicatively connected to the at least one processor 201; wherein the memory 202 stores instructions that can be executed by the at least one processor 201, and the instructions are executed by the at least one processor 201 so that the at least one processor 301 can execute the design method of the energy storage device in the above-mentioned embodiments.

[0118] The memory and processor are connected using a bus, which can include any number of interconnected buses and bridges. The bus connects various circuits of one, two, or more processors and memories. The bus can also connect various other circuits such as peripherals, voltage regulators, and power management circuits. These are all well known in the art and are therefore not described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single component or two or more components, such as two or more receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over a wireless medium via an antenna. Furthermore, the antenna receives data and transmits it to the processor.

[0119] The processor is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory can be used to store data used by the processor when performing operations.

[0120] The present application also relates to a computer-readable storage medium storing a computer program, which implements the above method embodiment when executed by a processor.

[0121] That is, those skilled in the art will understand that all or part of the steps in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a program, which is stored in a storage medium and includes a number of instructions for causing a device (which can be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps in the various embodiments of the present application. The aforementioned storage medium includes: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, etc., various media that can store program code.

[0122] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. An energy storage device, characterized in that: include: A DC energy storage valve, comprising energy storage modules connected in series, the energy storage modules comprising a power module and an energy storage unit, the DC energy storage valve being used to provide a DC voltage; The DC side is connected to a three-phase modular multilevel converter circuit at both ends of the DC energy storage valve. The three-phase modular multilevel converter circuit includes two or more modular multilevel converter submodules, each of the modular multilevel converter submodules is a full-bridge submodule or a half-bridge submodule, and the proportion of the full-bridge submodules in the two or more modular multilevel converter submodules is determined according to the target adjustment range of the DC voltage.

2. The energy storage device according to claim 1, characterized in that The number of the three-phase modular multilevel converter circuits is N, where N is a positive integer greater than 1, and the N three-phase modular multilevel converter circuits are connected in parallel at both ends of the DC energy storage valve; The proportions of the full-bridge sub-modules in the N three-phase modular multi-level converter circuits are different; Alternatively, the number of the full-bridge sub-modules of the M three-phase modular multi-level converter circuits in the N three-phase modular multi-level converter circuits is the same, and M is a positive integer less than or equal to N.

3. The energy storage device according to claim 1, characterized in that The three-phase modular multilevel converter circuit includes two or more modular multilevel converter bridge arms, and each modular multilevel converter bridge arm includes two or more modular multilevel converter sub-modules; Each of the modular multilevel converter bridge arms includes the full-bridge submodule and the half-bridge submodule; or some of the modular multilevel converter bridge arms only include the full-bridge submodule; or some of the modular multilevel converter bridge arms only include the half-bridge submodule.

4. The energy storage device according to claim 3, characterized in that The number of the full-bridge sub-modules in the two or more modular multi-level converter bridge arms is the same.

5. The energy storage device according to claim 1, characterized in that The number of the DC energy storage valves is two or more, and the two or more DC energy storage valves are connected in parallel.

6. A design method for an energy storage device, characterized in that: For designing an energy storage device according to any one of claims 1 to 5, the design method of the energy storage device comprising: Obtaining a target adjustment range of the DC voltage of the energy storage device, the target adjustment range including a voltage lower limit and a voltage upper limit; Determining a ratio of the number of full-bridge submodules of the three-phase modular multi-level converter circuit in the energy storage device according to a voltage ratio of the voltage lower limit to the voltage upper limit; The number of the energy storage modules in the DC energy storage valve is determined according to the voltage upper limit.

7. The design method of the energy storage device according to claim 6, characterized in that: The determining, based on the voltage ratio of the voltage lower limit to the voltage upper limit, of the proportion of the number of full-bridge submodules of the three-phase modular multilevel converter circuit in the energy storage device includes: Providing a preset correspondence list, the preset correspondence list including a one-to-one correspondence between two or more preset voltage ratios and two or more preset quantity proportions; The quantity ratio of the full-bridge sub-modules is determined according to the preset corresponding list and the voltage ratio.

8. The design method of the energy storage device according to claim 6, characterized in that: Determining the number of the energy storage modules in the DC energy storage valve according to the voltage upper limit includes: Obtaining a submodule voltage of the energy storage module; The number of energy storage modules in each DC energy storage valve in the energy storage device is determined according to the voltage upper limit and the submodule voltage.

9. The design method of the energy storage device according to claim 8, characterized in that: The design method of the energy storage device also includes: The capacitance value of the submodule capacitor in the energy storage module is determined according to the submodule voltage.

10. The design method of the energy storage device according to claim 8, characterized in that: The design method of the energy storage device also includes: Obtaining a target energy storage capacity of the energy storage device; Determining the number of energy storage units in each energy storage module connected in parallel according to the target energy storage capacity and the number of energy storage modules in each DC energy storage valve; or The number of the DC energy storage valves connected in parallel is determined according to the target energy storage capacity and the number of energy storage modules in each DC energy storage valve.

11. An electronic device, characterized in that: include: at least one processor; and, a memory communicatively coupled to the at least one processor; The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the design method of the energy storage device according to any one of claims 6 to 10.

12. A computer-readable storage medium storing a computer program, characterized in that: The computer program is executed by a processor to implement the method for designing an energy storage device according to any one of claims 6 to 10.

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