Energy storage system

Abstract

The invention provides an energy storage system. The energy storage system comprises an energy storage bridge arm, the energy storage bridge arm comprises a plurality of energy storage sub-modules and a plurality of sub-module controllers, and the sub-module controllers are connected with the energy storage sub-modules; the energy storage system further comprises a first network switch and a second network switch which are redundant to each other. The plurality of sub-module controllers in the energy storage bridge arm are in networking connection with the first network switch and the second network switch in a predetermined networking mode. The first main controller and the second main controller are redundant to each other, the first main controller is respectively connected with the first network switch and the second network switch, and the second main controller is respectively connected with the first network switch and the second network switch. The first master controller and the second master controller communicate with the plurality of sub-module controllers through the first network switch or the second network switch, and the first master controller and the second master controller are used for carrying out charging and discharging management on the plurality of energy storage sub-modules through the plurality of sub-module controllers.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular, to an energy storage system. Background Art

[0002] With the development of electric energy, the technology of battery energy storage system (BESS) has also gradually developed. People store electric energy in the energy storage system and use it when needed. The energy storage system can be connected to new energy power generation equipment to draw electricity from the new energy power generation equipment, or it can be connected to the power load to discharge the power load, and it can also be connected to the power grid to draw electricity from the power grid and discharge to the power grid.

[0003] At present, the communication method of high-voltage cascade energy storage system is generally carried out by optical fiber, and the communication protocol and method are all customized and developed. However, due to the huge area occupied by the energy storage system, the high voltage of the access grid, and the high requirements for the optical fiber required, the traditional communication method is very expensive and does not have the capacity expansion capability of large-scale systems. In addition, when a communication module on the communication link in the energy storage system fails, it will cause the entire system to fail, making the reliability of the entire system relatively low. Summary of the invention

[0004] The main purpose of the present application is to provide an energy storage system to at least solve the problems of poor expansion capacity and reliability of energy storage systems in the prior art.

[0005] To achieve the above-mentioned purpose, according to one aspect of the present application, there is provided an energy storage system, the energy storage system comprising an energy storage bridge arm, the energy storage bridge arm comprising a plurality of energy storage submodules and a plurality of submodule controllers, the submodule controller being connected to the energy storage submodule, the submodule controller being used to perform data acquisition and control on the energy storage submodule; the energy storage system further comprising: a first network switch and a second network switch which are mutually redundant, the plurality of submodule controllers in the energy storage bridge arm being respectively networked with the first network switch and the second network switch in a predetermined networking manner, the predetermined networking manner comprising a star networking and / or a ring networking; a first master controller and a second master controller which are mutually redundant, the first master controller being respectively connected to the first network switch and the second network switch, the second master controller being respectively connected to the first network switch and the second network switch, the first master controller and the second master controller both communicating with the plurality of submodule controllers through the first network switch or the second network switch, the first master controller and the second master controller being used to perform charge and discharge management on the plurality of energy storage submodules through the plurality of submodule controllers.

[0006] Optionally, the multiple submodule controllers in the energy storage bridge arm are divided into multiple ring network groups, and each of the ring network groups is networked and connected to the first network switch and the second network switch respectively using a ring network.

[0007] Optionally, there are 3n energy storage bridge arms in the energy storage system, where n is a positive integer, and the multiple sub-module controllers of each energy storage bridge arm are networked with the first network switch and the second network switch.

[0008] Optionally, the energy storage submodule includes a battery cluster, and the submodule controller is further used to implement a BMS (Battery Management System) function of the battery cluster.

[0009] Optionally, the energy storage submodule includes a battery cluster, a first slow start circuit, a DC filter circuit and an inverter circuit, the DC filter circuit includes a capacitor, the energy storage bridge arm also includes a second slow start circuit, the first end of the first slow start circuit is electrically connected to the first end of the battery cluster, the first end of the capacitor is electrically connected to the second end of the first slow start circuit, the second end of the capacitor is electrically connected to the second end of the battery cluster, the inverter circuit is connected in parallel at both ends of the capacitor, the inverter circuits of the multiple energy storage submodules in the energy storage bridge arm are connected in series in sequence, one end of the inverter circuit located at the first end of the series connection is electrically connected to the second slow start circuit, and the inverter circuit of the first main When the first main controller receives a black start instruction, the first main controller detects the status of the corresponding battery cluster through each sub-module controller. When it is detected that the status of all the battery clusters is normal, the first main controller controls each of the first slow start circuits to be turned on for a predetermined time through each sub-module controller to charge each of the capacitors; when all of the capacitors are charged, the first main controller controls each of the inverter circuits and each of the second slow start circuits to be turned on through each of the sub-module controllers, so that the output voltage of the energy storage sub-module rises to the target voltage value with a predetermined slope, so as to complete the black start of each of the energy storage sub-modules.

[0010] Optionally, the first main controller detects the state of the corresponding battery cluster through each of the sub-module controllers, including: the first main controller sends a first control signal to the plurality of sub-module controllers, so that the plurality of sub-module controllers detect the temperature and voltage of the corresponding battery cluster in response to the first control signal, and when the temperature is within the temperature range and the voltage is within the voltage range, determines that the state of the battery cluster is normal, and sends a first feedback signal carrying the voltage to the first main controller; the first main controller determines the predetermined time length corresponding to each of the first slow start circuits according to the voltage; the first main controller controls each of the first slow start circuits to be turned on for a predetermined time length through each of the sub-module controllers to charge each of the capacitors, including: the first main controller sends a second control signal carrying the predetermined time length to the plurality of sub-module controllers A module controller, so that the sub-module controller controls the first slow start circuit to turn on in response to the second control signal to charge the capacitor, controls the first slow start circuit to turn off when the start time reaches the predetermined time, and sends a second feedback signal to the first main controller; the first main controller controls each of the inverter circuits and each of the second slow start circuits to turn on through each of the sub-module controllers, including: the first main controller sends a third control signal to multiple sub-module controllers, so that the sub-module controller controls each of the second slow start circuits to turn on in response to the third control signal, and gradually increases the control voltage of the inverter circuit, when the control voltage reaches the voltage threshold of the inverter circuit, the inverter circuit is turned on, and after the inverter circuit is turned on, the sub-module controller controls the second slow start circuit to turn off.

[0011] Optionally, the energy storage submodule also includes a bypass switch, and the inverter circuit is electrically connected to the second soft-start circuit through the bypass switch. When a fault of the energy storage submodule is detected, the first main controller controls the bypass switch to be disconnected through the submodule controller to bypass the faulty energy storage submodule; when the number of bypassed energy storage submodules is greater than a first set value, the first main controller controls the energy storage system to shut down.

[0012] Optionally, the first main controller collects the charge state of the energy storage sub-module through the sub-module controller, and controls the power of each energy storage sub-module according to the charge state, so that the difference in the charge state of any two energy storage sub-modules is less than a second set value; when the difference after the control of the energy storage sub-module is greater than a third set value, the first main controller controls the bypass switch to be disconnected through the sub-module controller to bypass the energy storage sub-module, and the second set value is less than the third set value.

[0013] Optionally, in the energy storage bridge arm, the adjacent submodule controllers according to the connection order of the ring networking are connected by dual links. In the event of a link failure between two submodule controllers, the first network switch switches the connection link between the two submodule controllers to another link.

[0014] Optionally, the first network switch serves as a communication path between the first main controller and each of the sub-module controllers. In the event of a failure of the first network switch, the first main controller switches the communication path to the second network switch; in the event of a failure of the first main controller, the second main controller takes over the work of the first main controller.

[0015] By applying the technical solution of the present application, a plurality of energy storage submodules and submodule controllers are arranged in the energy storage bridge arm of the energy storage system to form a modular multi-level energy storage structure. The plurality of submodule controllers are respectively connected to the first and second network switches through star and / or ring networking modes. The first and second network switches are connected to the first main controller. The first and second network switches are also connected to the second main controller. The communication connection between the mutually redundant first and second main controllers and the submodule controllers is realized through the mutually redundant first and second network switches, forming a primary and secondary redundant communication network. When some components in the primary and secondary redundant communication network fail, the redundant components can take over their functions, so that the energy storage system can still continue to operate, that is, the primary and secondary redundant communication network provides additional resources and paths to ensure the reliability and fault tolerance of the system, thereby ensuring that the communication reliability of the energy storage system is high; and the main controller of the present application is connected to the submodule controller through a network switch. Compared with the optical fiber connection mode in the prior art, the connection mode of the network switch of the present application can easily realize the expansion of the network by increasing the number of ports of the network switch, and can support large-scale system expansion, thereby ensuring that the expansion capacity of the energy storage system is strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0017] Figure 1 A schematic structural diagram of an energy storage part of an energy storage system provided in an embodiment of the present application is shown;

[0018] Figure 2 A schematic diagram of the structure of a communication part of an energy storage system provided according to an embodiment of the present application is shown;

[0019] Figure 3A schematic diagram of the structure of an energy storage part of another energy storage system provided according to an embodiment of the present application is shown;

[0020] Figure 4 A schematic structural diagram of an energy storage bridge arm provided according to an embodiment of the present application is shown;

[0021] Figure 5 A schematic structural diagram of a communication part of another energy storage system provided according to an embodiment of the present application is shown;

[0022] Figure 6 A schematic structural diagram of a communication part of another energy storage system provided according to an embodiment of the present application is shown.

[0023] The above drawings include the following reference numerals:

[0024] 10. Energy storage bridge arm; 11. Energy storage submodule; 12. Submodule controller; 13. First network switch; 14. Second network switch; 15. First main controller; 16. Second main controller; 17. Battery cluster; 18. First slow start circuit; 19. DC filter circuit; 20. Inverter circuit; 21. Capacitor; 22. Second slow start circuit; 23. Bypass switch; 24. First switch device; 25. First voltage divider device; 26. Second switch device; 27. Third switch device; 28. Second voltage divider device; 29. ​​Fourth switch device; 30. First inductor; 31. First fuse; 32. Second fuse; 33. Power grid; 34. Second inductor; 35. Third fuse. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in 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. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0028] As introduced in the background technology, the prior art has the problem of poor expansion capability and reliability of energy storage systems. To solve this technical problem, an embodiment of the present application provides an energy storage system.

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0030] The embodiment of the present application provides an energy storage system, such as Figure 1 and Figure 2 As shown, the energy storage system includes an energy storage bridge arm 10, and the energy storage bridge arm 10 includes a plurality of energy storage submodules 11 and a plurality of submodule controllers 12 (one energy storage bridge arm 10 includes Figure 1 A row of energy storage submodules 11 and Figure 2 A column of submodule controllers 12 in the energy storage submodule 11, wherein the submodule controller 12 is connected to the energy storage submodule 11, and the submodule controller 12 is used to collect data and control the energy storage submodule 11;

[0031] Specifically, the energy storage submodule 11 can be connected to the submodule controller 12 in a one-to-one correspondence, and the submodule controller 12 controls the energy storage submodule 11 in a one-to-one correspondence and collects its data; one energy storage submodule 11 can be connected to multiple submodule controllers 12, and multiple submodule controllers 12 can collaboratively control one energy storage submodule 11 and collect its data; one submodule controller 12 can be connected to multiple energy storage submodules, and one submodule controller can control multiple energy storage submodules 11 and collect their data.

[0032] The above energy storage system also includes:

[0033] A first network switch 13 and a second network switch 14 which are redundant to each other, and a plurality of the submodule controllers 12 in the energy storage bridge arm 10 are respectively networked and connected with the first network switch 13 and the second network switch 14 in a predetermined networking manner, wherein the predetermined networking manner includes a star networking and / or a ring networking;

[0034] The first main controller 15 and the second main controller 16 are redundant with each other. The first main controller 15 is connected to the first network switch 13 and the second network switch 14 respectively. The second main controller 16 is connected to the first network switch 13 and the second network switch 14 respectively. The first main controller 15 and the second main controller 16 both communicate with the plurality of sub-module controllers 12 through the first network switch 13 or the second network switch 14. The first main controller 15 and the second main controller 16 are used to manage the charging and discharging of the plurality of energy storage sub-modules 11 through the plurality of sub-module controllers 12.

[0035] Specifically, the first main controller 15 and the second main controller 16 can communicate with the multiple sub-module controllers 12 through the first network switch 13 respectively; the first main controller 15 and the second main controller 16 can also communicate with the multiple sub-module controllers 12 through the second network switch 14 respectively.

[0036] Through the above embodiments, a plurality of energy storage submodules and submodule controllers are arranged in the energy storage bridge arm of the energy storage system to form a modular multi-level energy storage structure. The plurality of submodule controllers are respectively connected to the first and second network switches through star and / or ring networking modes. The first and second network switches are connected to the first main controller. The first and second network switches are also connected to the second main controller. The communication connection between the mutually redundant first and second main controllers and the submodule controllers is realized through the mutually redundant first and second network switches, forming a primary and secondary redundant communication network. When some components in the primary and secondary redundant communication network fail, the redundant components can take over their functions, so that the energy storage system can still continue to operate, that is, the primary and secondary redundant communication network provides additional resources and paths to ensure the reliability and fault tolerance of the system, thereby ensuring that the communication reliability of the energy storage system is high; and the main controller and the submodule controller of the present application are connected through a network switch. Compared with the optical fiber connection mode in the prior art, the connection mode of the network switch of the present application can easily realize the expansion of the network by increasing the number of ports of the network switch, and can support large-scale system expansion, thereby ensuring that the expansion capacity of the energy storage system is strong.

[0037] In the present application, the communication medium between the first main controller, the second main controller, the first network switch, the second network switch and the submodule controller can be optical fiber or network cable. Since the high-voltage cascade energy storage system is generally arranged in a centralized manner, the communication medium can be considered to be a network cable.

[0038] In the specific application process, when the number of submodule controllers in the energy storage bridge arm is large, the above-mentioned ring networking method can be used; when the number of submodule controllers in the energy storage bridge arm is small, the above-mentioned star networking method can be used. In addition, multiple submodule controllers in one of the above energy storage bridge arms can form a ring network with the first network switch through a ring networking method, and at the same time form a ring network with the second network switch; multiple submodule controllers in one of the above energy storage bridge arms can also form multiple ring networks with the first network switch through a ring networking method, and at the same time form multiple ring networks with the second network switch.

[0039] The first main controller performs point-to-point communication with all the submodule controllers through the first network switch or the second network switch. Similarly, the second main controller performs point-to-point communication with all the submodule controllers through the first network switch or the second network switch.

[0040] In an optional embodiment, the multiple submodule controllers in the energy storage bridge arm are divided into multiple ring network groups, and each of the ring network groups is networked with the first network switch and the second network switch respectively by ring networking. In this embodiment, multiple submodule controllers in an energy storage bridge arm constitute multiple ring network groups, and multiple submodule controllers in each ring network group are networked with the network switch by ring networking to form a ring network. When a submodule controller in a ring network fails, it does not affect the operation of submodule controllers in other ring networks, thereby further improving the reliability of the energy storage system, and can be applied to scenarios with a large number of submodule controllers in an energy storage bridge arm.

[0041] Specifically, when the number of the above-mentioned sub-module controllers in an energy storage bridge arm is greater than 15, the sub-module controllers in the energy storage bridge arm can be divided into multiple ring network groups; when the number of the above-mentioned sub-module controllers in an energy storage bridge arm is less than or equal to 15, the sub-module controllers in the energy storage bridge arm may not be grouped.

[0042] Alternatively, if Figure 2As shown, there are 3n energy storage bridge arms 10 in the energy storage system, where n is a positive integer, and the multiple submodule controllers 12 of each energy storage bridge arm 10 are networked and connected to the first network switch 13 and the second network switch 14. In the present application, the energy storage system has a multi-phase energy storage bridge arm, and the submodule controllers of each phase of the energy storage bridge arm are connected to each other using a primary and standby redundant communication network, which can further ensure that the communication reliability and stability of the energy storage system are high.

[0043] In a specific embodiment, Figure 3 As shown, n=3, corresponding to the three-phase electricity of the grid 33. The three-phase energy storage bridge arm can be connected in a △ shape or a Y shape and directly connected to the high-voltage grid. When the modulation wave has a lower frequency, the current harmonics on the grid side can be greatly reduced, thereby reducing the volume of the filter element.

[0044] Figure 3 The schematic diagram of the structure of the energy storage submodule of a three-phase energy storage bridge arm according to the present application is shown exemplarily. It should be noted that: Figure 3 Only the specific structure of one energy storage submodule 11 is shown (see Figure 3 The specific structure of the other energy storage submodules 11 is the same as the specific structure of the energy storage submodule 11 shown.

[0045] like Figure 1 and Figure 3 As shown, the energy storage submodules 11 located at the connection tails in each energy storage bridge arm are connected together.

[0046] According to other embodiments of the present application, Figure 3 and Figure 4 As shown, the energy storage submodule 11 includes a battery cluster 17, and the submodule controller 12 is also used to implement the BMS function of the battery cluster 17. That is, the present application integrates the BMS function into the submodule controller, so that each submodule controller controls the corresponding energy storage submodule to implement the BMS function, without providing an independent BMS system for the energy storage system.

[0047] Specifically, when executing the BMS function, the sub-module controller obtains the functional information of the corresponding energy storage sub-module, the above functional information includes SOC, SOH and fault status, and sends it to the first main controller or the second main controller. The first main controller or the second main controller sends a control instruction to each sub-module controller based on the functional information to connect the corresponding energy storage sub-module to the energy storage system or cut it out of the energy storage system, thereby realizing balanced control of the energy storage sub-module.

[0048] In some other optional embodiments, Figure 3 and Figure 4As shown, the energy storage submodule 11 includes a battery cluster 17, a first slow start circuit 18, a DC filter circuit 19 and an inverter circuit 20. The DC filter circuit 19 includes a capacitor 21. The energy storage bridge arm 10 also includes a second slow start circuit 22. The first end of the first slow start circuit 18 is electrically connected to the first end of the battery cluster 17. The first end of the capacitor 21 is electrically connected to the second end of the first slow start circuit 18. The second end of the capacitor 21 is electrically connected to the second end of the battery cluster 17. The inverter circuit 20 is connected in parallel to both ends of the capacitor 21. The inverter circuits 20 of the multiple energy storage submodules 11 in the energy storage bridge arm 10 are connected in series in sequence, and one end of the inverter circuit 20 located at the first end of the series connection is electrically connected to the second slow start circuit 22.

[0049] In the present application, the first slow start circuit and the second slow start circuit are used to realize the slow start function, specifically, the first slow start circuit is used to control the DC current and voltage in the circuit to gradually increase. The second slow start circuit is used to control the AC current and voltage in the circuit to gradually increase.

[0050] The DC filter circuit is used to remove AC components and noise from DC signals and improve the purity and stability of the DC power supply.

[0051] like Figure 3 and Figure 4 As shown, the battery cluster 17 is composed of a number of cells connected in series and in parallel, and also includes a voltage and current collector and a temperature collector. The inverter circuit 20 can be a half-bridge inverter circuit, or can be a Figure 3 and Figure 4 The full-bridge (H-bridge) inverter circuit shown in Figure 1 is shown in Figure 2. Figure 4 As shown, the inverter circuit includes four switching tubes T1-T4 and four diodes D1-D4, wherein the diodes D1-D4 are respectively connected in parallel at both ends of the switching tubes T1-T4, the anode of the diode is electrically connected to the output end of the switching tube, and the cathode of the diode is electrically connected to the input end of the switching tube. The output end of the switching tube T1 is electrically connected to the input end of the switching tube T2 as the first end of the inverter circuit; the output end of the switching tube T3 is electrically connected to the input end of the switching tube T4 as the second end of the inverter circuit; the input end of the switching tube T1 is electrically connected to the input end of the switching tube T3, and is electrically connected to one end of the capacitor 21; the output end of the switching tube T2 is electrically connected to the output end of the switching tube T4, and is electrically connected to the other end of the capacitor 21. The submodule controller 12 implements the PCS (Power Conversion System) function of the energy storage submodule through the above-mentioned inverter circuit 20. When executing the PCS function, the first main controller 15 or the second main controller 16 is used to control each energy storage submodule through each submodule controller 12 to achieve the fitting of the AC sinusoidal waveform, thereby realizing the conversion between DC and AC.

[0052] In this embodiment, the default Figure 2 The first main controller 15 is the main machine of the two main controllers, and the second main controller 16 is the backup machine of the two main controllers. When the main machine is in normal working state, based on the above structure, when the first main controller 15 receives a black start instruction, the first main controller 15 detects the state of the corresponding battery cluster 17 through the sub-module controllers 12. When it is detected that the states of all the battery clusters 17 are normal, the first main controller 15 controls the first slow start circuits 18 to be turned on for a predetermined time through the sub-module controllers 12 to charge the capacitors 21. When all the capacitors 21 are fully charged, the first main controller 15 controls the inverter circuits 20 and the second slow start circuits 22 to be turned on through the sub-module controllers 12, so that the output voltage of the energy storage sub-module 11 rises to the target voltage value at a predetermined slope to complete the black start of the energy storage sub-module 11.

[0053] In the above embodiment, when the first main controller receives the black start instruction, it will detect the status of the battery cluster through the sub-module controller to ensure that all battery clusters are in normal status; then, the first slow start circuit is controlled to start, and the capacitors in the DC filter circuit are charged; when all capacitors are charged, the inverter circuit and the second slow start circuit are controlled to start, so that the output voltage of the energy storage sub-module rises to the target voltage value at a predetermined slope, and the black start of the energy storage sub-module is completed. This design improves the reliability and stability of the energy storage system, reduces the risk during the startup process, and realizes efficient management and control of the energy storage sub-module.

[0054] In some embodiments, the first main controller 15 performs status detection on the corresponding battery cluster 17 through each of the submodule controllers 12, including: the first main controller 15 sends a first control signal to the plurality of submodule controllers 12, so that the plurality of submodule controllers 12 detect the temperature and voltage of the corresponding battery cluster 17 in response to the first control signal, and when the temperature is within the temperature range and the voltage is within the voltage range, it is determined that the status of the battery cluster 17 is normal, and a first feedback signal carrying the voltage is sent to the first main controller 15. The first main controller 15 automatically sends a control signal to the submodule controller 12 to realize automatic detection of the temperature and voltage of the battery cluster 17; after detecting that the status of the battery cluster 17 is normal, the submodule controller 12 sends a feedback signal carrying voltage information to the first main controller 15, ensuring real-time update of the status information.

[0055] In some embodiments, the first main controller 15 determines the predetermined time corresponding to each of the first slow start circuits 18 according to the voltage. The first main controller 15 determines the start time of each of the first slow start circuits 18 according to the voltage of the battery cluster 17, which helps optimize energy management and ensures that the capacitor 21 is charged at an appropriate rate.

[0056] In some embodiments, the first main controller 15 controls each of the first slow start circuits 18 to be turned on for a predetermined time through each of the sub-module controllers 12 to charge each of the capacitors 21, including: the first main controller 15 sends a second control signal carrying the predetermined time to the plurality of sub-module controllers 12, so that the sub-module controllers 12 control the first slow start circuit 18 to be turned on in response to the second control signal to charge the capacitor 21, and control the first slow start circuit 18 to be turned off when the turn-on time reaches the predetermined time, and send a second feedback signal to the first main controller 15. The first main controller 15 controls the sub-module controller 12 to turn on the first slow start circuit 18 to charge the capacitor 21 and turn it off after the predetermined time is reached by sending the second control signal, which helps to prevent overcharging.

[0057] In some embodiments, the first main controller 15 controls each of the inverter circuits 20 and each of the second slow start circuits 22 to start through each of the sub-module controllers 12, including: the first main controller 15 sends a third control signal to the plurality of sub-module controllers 12, so that the sub-module controllers 12 control each of the second slow start circuits 22 to start in response to the third control signal, and gradually increase the control voltage of the inverter circuit 20, and when the control voltage reaches the voltage threshold of the inverter circuit 20, the inverter circuit 20 is turned on, and after the inverter circuit 20 is turned on, the sub-module controller 12 controls the second slow start circuit 22 to turn off. The first main controller 15 controls the sub-module controller 12 to gradually increase the control voltage of the inverter circuit 20 through the third control signal until the voltage threshold is reached, so as to achieve smooth startup of the inverter circuit and reduce the current impact during startup.

[0058] During the entire black start process, the first master controller flexibly controls the submodule controllers based on real-time feedback and preset parameters, improving the responsiveness and flexibility of the system. By accurately controlling the charging and starting process, overcharging and overdischarging of the battery cluster can be reduced, thereby extending the service life of the battery cluster. By optimizing the charging and starting process, energy waste can be reduced and the efficiency of the entire battery management system can be improved. The system reduces the need for manual intervention through automatic detection and control, thereby reducing maintenance costs and operational complexity.

[0059] In addition, the first main controller determines that the states of all the battery clusters are normal when receiving all the first feedback signals, and determines that the charging of all the capacitors is complete when receiving all the second feedback signals.

[0060] In an actual design process, the circuit structure of the first slow start circuit may be the same as the circuit structure of the second slow start circuit; the circuit structure of the first slow start circuit may also be different from the circuit structure of the second slow start circuit.

[0061] In some embodiments, Figure 2 As shown, the first slow start circuit 18 comprises:

[0062] a first switch device 24, wherein the first end of the first switch device 24 is the first end of the first slow start circuit 18, that is, the first end of the first switch device 24 is electrically connected to the first end of the battery cluster 17, and the second end of the first switch device 24 is the second end of the first slow start circuit 18, that is, the second end of the first switch device 24 is electrically connected to the first end of the capacitor 21;

[0063] A first voltage divider device 25, wherein a first end of the first voltage divider device 25 is electrically connected to a first end of the first switch device 24, that is, a first end of the first voltage divider device 25 is electrically connected to a first end of the battery cluster 17;

[0064] The second switch device 26, the first end of the second switch device 26 is electrically connected to the second end of the first voltage divider device 25, and the second end of the second switch device 26 is electrically connected to the second end of the first switch device 24, that is, the second switch device 26 is connected in series with the first voltage divider device 25 and then connected in parallel at both ends of the first switch device 24.

[0065] In the above embodiment, when the above-mentioned first slow-start circuit is not turned on, the above-mentioned first switch device is closed and the above-mentioned second switch device is opened; when it is necessary to control the above-mentioned first slow-start circuit to be turned on, the above-mentioned first switch device is opened and the above-mentioned second switch device is closed, so that the first voltage divider device is connected between the capacitor and the battery cluster, thereby realizing the slow-start function; when it is necessary to control the first slow-start circuit to be turned off, it is realized by closing the above-mentioned first switch device and disconnecting the above-mentioned second switch device, that is, the above-mentioned first switch device short-circuits the above-mentioned first voltage divider device to turn off the slow-start function of the first slow-start circuit.

[0066] Those skilled in the art can select any suitable switch type as the first switch device and the second switch device, for example, select transistors such as MOS or triodes as the first switch device and the second switch device. For another example, select a single-pole double-throw switch as the combination structure of the first switch device and the second switch device. The first voltage divider device can be any suitable device that can play a voltage divider role, such as a resistor, an inductor, or a series-parallel combination of a resistor and an inductor.

[0067] In some embodiments, Figure 2 As shown, the second slow start circuit 22 comprises:

[0068] A third switch device 27, wherein a first end of the third switch device 27 is electrically connected to one end of the inverter circuit 20, and a second end of the third switch device 27 is electrically connected to the power grid 33;

[0069] A second voltage divider device 28, wherein a first end of the second voltage divider device 28 is electrically connected to a first end of the third switch device 27;

[0070] The fourth switch device 29, the first end of the fourth switch device 29 is electrically connected to the second end of the second voltage divider device 28, and the second end of the fourth switch device 29 is electrically connected to the second end of the third switch device 27, that is, the fourth switch device 29 is connected in series with the second voltage divider device 28 and then connected in parallel at both ends of the third switch device 27.

[0071] In the above embodiment, when the second slow-start circuit is not turned on, the third switch device is closed and the fourth switch device is opened; when it is necessary to control the second slow-start circuit to be turned on, the third switch device is opened and the fourth switch device is closed, so that the second voltage divider device is connected between the inverter circuit and the power grid, thereby realizing the slow-start function; when it is necessary to control the second slow-start circuit to be turned off, the third switch device is closed and the fourth switch device is opened, that is, the second voltage divider device is short-circuited by the third switch device to turn off the slow-start function of the second slow-start circuit.

[0072] Those skilled in the art can select any suitable switch type as the third switch device and the fourth switch device, for example, select transistors such as MOS or triodes as the third switch device and the fourth switch device. For another example, select a single-pole double-throw switch as the combination structure of the third switch device and the fourth switch device. The second voltage divider device can be any suitable device that can play a voltage divider role, such as a resistor, an inductor, or a series-parallel combination of a resistor and an inductor.

[0073] In some embodiments, Figure 2As shown, the DC filter circuit 19 further includes a first inductor 30, and the energy storage submodule 11 further includes: a first fuse 31, through which the first switch device 24 is electrically connected to the first end of the battery cluster 17; and a second fuse 32, through which the second end of the capacitor 21 is electrically connected to the second end of the battery cluster 17 in sequence through the first inductor 30 and the second fuse 32. By providing the first fuse and the second fuse, when an abnormality occurs in the circuit, the fuse can disconnect the circuit in time to protect key components such as the battery cluster and the capacitor, avoid damage caused by abnormal conditions such as overcurrent and overvoltage, and improve the safety of the system; in addition, by providing the first inductor, the filtering performance of the DC filter circuit can be further optimized, the ripple current on the DC side can be reduced, the damage to components such as the battery cluster and the capacitor can be reduced, and the overall stability and reliability of the system can be improved.

[0074] In the present application, the LC frequency-doubling current suppression circuit structure is formed by connecting a capacitor and a first inductor in series, which can further suppress or reduce the frequency-doubling signal in the circuit, thereby improving the performance and stability of the circuit, and reducing electromagnetic interference and improving the safety of the circuit.

[0075] In addition, if Figure 2 As shown, the energy storage bridge arm 10 further includes: a third fuse 35, the second end of the third switch device 27 is used to be electrically connected to the power grid 33 through the third fuse 35; a second inductor 34, the first end of the third switch device 27 is electrically connected to one end of the inverter circuit 20 located at the first position in series through the second inductor 34. As an overload protection device, the third fuse can automatically disconnect the circuit when the current rises abnormally, protect the circuit from damage, and avoid equipment damage caused by overload. The addition of the second inductor helps to smooth current fluctuations, reduce the impact of transient current on the circuit, and improve the stability and reliability of the circuit.

[0076] like Figure 4 As shown, the submodule controller 12 is further used to perform bypass control on the energy storage submodule 11 through the bypass switch 23 in the energy storage submodule 11, and to perform power control on the energy storage submodule 11 through the inverter circuit 20 in the energy storage submodule 11, and to perform submodule protection on the energy storage submodule 11 through the DC filter circuit 19, the first fuse 31 and the second fuse 32 in the energy storage submodule 11, and to perform voltage and current acquisition on the energy storage submodule 11 through the voltage and current collector in the battery cluster 17, and to perform soft start control on the energy storage submodule 11 through the first soft start circuit 18 in the energy storage submodule 11, and to control the battery cluster 17 in the energy storage submodule 11 to realize the BMS function.

[0077] In the present application, the black start of the energy storage system requires a UPS (Uninterruptible Power Supply) to supply power to the first main controller and each sub-module controller. The first main controller receives an external black start instruction, and the black start process is executed according to the steps of establishing the DC voltage of the battery cluster, slow starting of the submodule DC, and slow starting of the power module voltage; wherein, in the step of establishing the DC voltage of the battery cluster, the submodule controller performs a power-on self-test on the battery cluster under it, and feeds back the voltage information to the first main controller after the voltage and temperature of the battery cluster are normal, and when all submodule controllers feed back normal, it is determined that the battery side of the system has the conditions for starting; in the step of slow starting of the submodule DC, the first main controller controls all submodule controllers to charge the capacitor through the first slow starting circuit and then removes the slow starting resistor (i.e., the first voltage divider device described below), at which point it is determined that the energy storage submodule has the conditions for starting; in the step of slow starting of the power module voltage, the first main controller controls the inverter circuits of all submodule controllers and the second slow starting circuit to realize the AC voltage slow starting conversion control, and the control realizes that the overall output voltage of the system rises according to the fixed voltage time slope according to the voltage slope control, and the process is completed after the voltage reaches the target value, at which point the system black start is completed.

[0078] It should be noted that, when the working state of the first main controller as the host is abnormal, the second main controller as the backup takes over the work of the first main controller and executes the black start process.

[0079] Alternatively, if Figure 3 and Figure 4 As shown, the energy storage submodule 11 further includes a bypass switch 23, and the inverter circuit 20 is electrically connected to the second slow start circuit 22 through the bypass switch 23. When the energy storage submodule 11 fails, the first main controller 15 controls the bypass switch 23 to be disconnected through the submodule controller 12 to bypass the failed energy storage submodule 11; when the number of bypassed energy storage submodules 11 is greater than the first set value, the first main controller 15 controls the energy storage system to shut down. In this embodiment, by setting a bypass switch, when the energy storage submodule fails, the submodule controller controls the bypass switch to be disconnected to bypass the failed energy storage submodule and realize the normal operation of the system, further ensuring the high operation stability and reliability of the energy storage system. Through the design of the bypass switch, the system can flexibly handle the failure of a single or multiple modules according to the actual operation conditions without having to shut down the entire system for comprehensive maintenance. When the number of bypassed energy storage submodules exceeds the first set value, the first master controller will control the energy storage system to shut down to prevent the system from causing greater safety risks due to too many faulty modules. In addition, this solution allows maintenance and replacement of some faulty energy storage submodules without completely shutting down the energy storage system, reducing system downtime and improving system availability and maintenance efficiency.

[0080] It should be noted that the initial state of the bypass switch is the closed state. When the corresponding energy storage submodule fails, the state of the bypass switch changes from the closed state to the open state. Figure 2 The first main controller 15 is the master of the two main controllers, and the second main controller 16 is the backup of the two main controllers, and the control process is performed when the master is in normal working condition. When the second main controller 16 is the master of the two main controllers and the first main controller 15 is the backup of the two main controllers, the control process only needs to swap the control priorities of the first main controller 15 and the second main controller 16, and other processes remain unchanged, which will not be repeated in this application.

[0081] According to some further optional schemes of the present application, the first main controller collects the charge state of the energy storage submodule through the submodule controller, and controls the power of each energy storage submodule according to the charge state, so that the difference between the charge states of any two energy storage submodules is less than a second set value; when the difference after the control of the energy storage submodule is greater than a third set value, the first main controller controls the bypass switch to be disconnected through the submodule controller to bypass the energy storage submodule, and the second set value is less than the third set value.

[0082] In the above embodiment, through the coordinated work of the first main controller and the sub-module controller, active balancing control of the charge state of the energy storage sub-module is achieved, ensuring that the charge state difference between the multiple energy storage sub-modules is within a safe range, avoiding safety hazards caused by excessive charge state difference. Specifically, when the charge state difference exceeds the third set value, the first main controller will control the bypass switch to disconnect through the sub-module controller to bypass the energy storage sub-module, thereby achieving rapid balancing control, further ensuring the safe and stable operation of the system, improving the reliability and safety of the energy storage system, reducing maintenance costs, and extending the service life of the energy storage sub-module.

[0083] In some embodiments, Figure 5As shown, in the energy storage bridge arm, the adjacent submodule controllers 12 are connected by dual links according to the connection sequence of the ring networking. When one link between the two submodule controllers 12 fails, the first network switch 13 switches the connection link between the two submodule controllers 12 to another link. In this embodiment, according to the connection sequence of the ring networking, the connection mode between two adjacent submodule controllers is set to dual link connection. When one of the links fails, the first network switch can quickly switch the connection link between the two submodule controllers to another link, thereby ensuring that the communication between the submodule controllers is not affected and maintaining the continuous operation of the entire system. This can not only further improve the communication reliability and stability of the system, but also enhance the fault tolerance of the system, reduce the system downtime caused by link failure, and improve the overall work efficiency.

[0084] It should be noted that the above process is the default Figure 5 The first network switch 13 is the host of the two network switches, and the second network switch 14 is the backup of the two network switches, and the control process is performed when the host is in normal working condition. For the control process in which the second network switch 14 is the host of the two network switches and the first network switch 13 is the backup of the two network switches, it is only necessary to swap the control priorities of the first network switch 13 and the second network switch 14, and other processes remain unchanged, which will not be described in detail in this application.

[0085] In some embodiments, Figure 5 As shown, each of the above submodule controllers 12 includes 4 communication ports. In the same energy storage bridge arm, according to the above connection sequence, multiple submodule controllers 12 form a double ring network (i.e., the above dual link connection mode) in a hand-in-hand manner and are connected to the first network switch 13 and the second network switch 14. According to the above connection sequence, one port of the submodule controller 12 located at the connection head and the connection tail is connected to the first network switch 13, and the other port is connected to the second network switch 14.

[0086] In addition, when there are many sub-module controllers in a storage bridge arm, the multiple sub-module controllers can be divided into multiple ring network groups, each ring network group includes multiple sub-module controllers, each of the ring network groups adopts ring networking for networking connection, and the multiple sub-module controllers in each of the ring network groups are connected in the order of the ring networking, and the adjacent sub-module controllers are connected by dual links to form multiple dual ring networks.

[0087] In some other embodiments, Figure 3As shown, each of the above submodule controllers 12 includes 3 communication ports. In the same energy storage bridge arm, according to the above connection sequence, multiple submodule controllers 12 form a single ring network connected to the first network switch 13 and the second network switch 14. According to the above connection sequence, one port of the submodule controller 12 located at the connection head and the connection tail is connected to the first network switch 13, and the other port is connected to the second network switch 14.

[0088] In some other embodiments, Figure 6 As shown, each of the above-mentioned sub-module controllers 12 includes two communication ports. In each energy storage bridge arm, one end of each sub-module controller 12 is connected to the first network switch 13, and the other end is connected to the second network switch 14. The first network switch 13 and the second network switch 14 are used to realize the networking of multiple sub-module controllers 12 in one energy storage bridge arm.

[0089] Specifically, the first network switch serves as a communication path between the first main controller and each of the sub-module controllers. In the event of a failure of the first network switch, the first main controller switches the communication path to the second network switch; in the event of a failure of the first main controller, the second main controller takes over the work of the first main controller. The present application achieves high reliability of communication by setting a master-slave main controller and a master-slave network switch. When the first network switch fails, the first main controller can automatically switch to communicate with the second network switch to ensure the continuity of communication. In addition, if the first main controller fails, the second main controller can take over its work, thereby ensuring the stable operation of the entire network system. This design improves the fault tolerance of the system, reduces the risk of system paralysis due to single point failures, and enhances the stability and reliability of the network system.

[0090] Optionally, both the first network switch and the second network switch are RSTP (Rapid Spanning Tree Protocol) ring network switches. That is to say, both the first network switch and the second network switch have RSTP ring network communication function. By using two RSTP ring network switches, the network can quickly switch to another when one switch fails, thereby reducing the risk of network interruption and further improving the reliability of the communication network. The design of RSTP allows for rapid reconfiguration when the network topology changes, which means that the network can be restored within seconds. RSTP is able to detect and prevent loops in the network, which can prevent data packets from circulating infinitely in the network, causing network congestion and performance degradation. RSTP can dynamically select the best path to direct traffic from one switch to another, thereby optimizing network performance. In short, by setting up redundant RSTP ring network switches, a relatively safe, reliable and efficient communication network environment is provided for the energy storage system.

[0091] The communication protocol of the first network switch and the network switch adopts IEC61850 SV / GOOSE, and the submodule controller synchronizes the trigger signal and compensates according to the fixed delay of the ring network GOOSE communication. Among them, in the IEC61850 standard, SV and GOOSE are two sub-protocols used for real-time communication and data transmission, which respectively stand for Sampled Values ​​and Generic Object Oriented Substation Event.

[0092] Specifically, when a single communication node fails in the ring network of the sub-module controller, the ring network RSTP function switches the ring network into two single-chain networks; when a sub-module controller communication fails, the bypass switch is controlled by the main controller hardware IO to bypass the sub-module controller; when a single sub-module controller detects a hardware failure or a battery cluster failure inside the energy storage sub-module, the main controller removes the bypass of the energy storage sub-module.

[0093] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order than here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0094] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0095] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0096] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0097] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0098] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0099] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0100] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0101] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0102] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0103] In the present application, a plurality of energy storage submodules and submodule controllers are arranged in the energy storage bridge arm of the energy storage system to form a modular multi-level energy storage structure. The plurality of submodule controllers are respectively connected to the first and second network switches through star and / or ring networking modes. The first and second network switches are connected to the first main controller. The first and second network switches are also connected to the second main controller. The communication connection between the mutually redundant first and second main controllers and the submodule controllers is realized through the mutually redundant first and second network switches, forming a primary and secondary redundant communication network. When some components in the primary and secondary redundant communication network fail, the redundant components can take over their functions, so that the energy storage system can still continue to operate, that is, the primary and secondary redundant communication network provides additional resources and paths to ensure the reliability and fault tolerance of the system, thereby ensuring that the communication reliability of the energy storage system is high; and the main controller and the submodule controllers of the present application are connected through a network switch. Compared with the optical fiber connection mode in the prior art, the connection mode of the network switch of the present application can easily realize the expansion of the network by increasing the number of ports of the network switch, and can support large-scale system expansion, thereby ensuring that the expansion capacity of the energy storage system is strong.

[0104] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An energy storage system, characterized in that: The energy storage system includes an energy storage bridge arm, the energy storage bridge arm includes a plurality of energy storage submodules and a plurality of submodule controllers, the submodule controller is connected to the energy storage submodule, and the submodule controller is used to collect data and control the energy storage submodule; The energy storage system further comprises: A first network switch and a second network switch which are redundant with each other, wherein the plurality of submodule controllers in the energy storage bridge arm are respectively networked and connected with the first network switch and the second network switch in a predetermined networking manner, wherein the predetermined networking manner includes a star networking and / or a ring networking; A first main controller and a second main controller are redundant with each other, the first main controller is connected to the first network switch and the second network switch respectively, the second main controller is connected to the first network switch and the second network switch respectively, the first main controller and the second main controller both communicate with the plurality of sub-module controllers through the first network switch or the second network switch, and the first main controller and the second main controller are used to manage the charging and discharging of the plurality of energy storage sub-modules through the plurality of sub-module controllers.

2. The energy storage system according to claim 1, characterized in that: The multiple submodule controllers in the energy storage bridge arm are divided into multiple ring network groups, and each of the ring network groups is networked and connected to the first network switch and the second network switch respectively using a ring network.

3. The energy storage system according to claim 1, characterized in that: There are 3n energy storage bridge arms in the energy storage system, where n is a positive integer, and the multiple sub-module controllers of each energy storage bridge arm are networked with the first network switch and the second network switch.

4. The energy storage system according to claim 1, characterized in that: The energy storage submodule includes a battery cluster, and the submodule controller is also used to implement the BMS function of the battery cluster.

5. The energy storage system according to claim 1, characterized in that: The energy storage submodule includes a battery cluster, a first slow start circuit, a DC filter circuit and an inverter circuit. The DC filter circuit includes a capacitor. The energy storage bridge arm also includes a second slow start circuit. The first end of the first slow start circuit is electrically connected to the first end of the battery cluster. The first end of the capacitor is electrically connected to the second end of the first slow start circuit. The second end of the capacitor is electrically connected to the second end of the battery cluster. The inverter circuit is connected in parallel at both ends of the capacitor. The inverter circuits of the multiple energy storage submodules in the energy storage bridge arm are connected in series in sequence. One end of the inverter circuit at the first end of the series connection is electrically connected to the second slow start circuit. When the first main controller receives a black start instruction, the first main controller detects the status of the corresponding battery cluster through each submodule controller, and when it is detected that the status of all the battery clusters is normal, the first main controller controls each of the first slow start circuits to be turned on for a predetermined time through each of the submodule controllers to charge each of the capacitors; When all the capacitors are charged, the first main controller controls each of the inverter circuits and each of the second slow-start circuits to start through each of the sub-module controllers, so that the output voltage of the energy storage sub-module rises to a target voltage value at a predetermined slope, thereby completing the black start of each of the energy storage sub-modules.

6. The energy storage system according to claim 5, characterized in that: The first main controller detects the state of the corresponding battery cluster through each of the submodule controllers, including: the first main controller sends a first control signal to the plurality of submodule controllers, so that the plurality of submodule controllers detect the temperature and voltage of the corresponding battery cluster in response to the first control signal, and when the temperature is within the temperature range and the voltage is within the voltage range, determines that the state of the battery cluster is normal, and sends a first feedback signal carrying the voltage to the first main controller; The first main controller determines the predetermined time length corresponding to each of the first slow start circuits according to the voltage; The first main controller controls each of the first slow start circuits to be turned on for a predetermined time through each of the sub-module controllers to charge each of the capacitors, including: the first main controller sends a second control signal carrying the predetermined time to the plurality of sub-module controllers, so that the sub-module controller controls the first slow start circuit to be turned on in response to the second control signal to charge the capacitor, controls the first slow start circuit to be turned off when the turn-on time reaches the predetermined time, and sends a second feedback signal to the first main controller; The first main controller controls each of the inverter circuits and each of the second slow-start circuits to start up through each of the sub-module controllers, including: the first main controller sends a third control signal to the plurality of sub-module controllers, so that the sub-module controller controls each of the second slow-start circuits to start up in response to the third control signal, and gradually increases the control voltage of the inverter circuit, and when the control voltage reaches a voltage threshold of the inverter circuit, the inverter circuit is turned on, and after the inverter circuit is turned on, the sub-module controller controls the second slow-start circuit to turn off.

7. The energy storage system according to claim 5, characterized in that: The energy storage submodule further includes a bypass switch, the inverter circuit is electrically connected to the second slow start circuit via the bypass switch, and when a fault of the energy storage submodule is detected, the first main controller controls the bypass switch to be disconnected via the submodule controller to bypass the faulty energy storage submodule; When the number of the bypassed energy storage submodules is greater than a first set value, the first main controller controls the energy storage system to shut down.

8. The energy storage system according to claim 7, characterized in that: The first main controller collects the charge state of the energy storage submodule through the submodule controller, and controls the power of each energy storage submodule according to the charge state, so that the difference in the charge state of any two energy storage submodules is less than a second set value; when the difference after the control of the energy storage submodule is greater than a third set value, the first main controller controls the bypass switch to be disconnected through the submodule controller to bypass the energy storage submodule, and the second set value is less than the third set value.

9. The energy storage system according to any one of claims 1 to 8, characterized in that: In the energy storage bridge arm, the adjacent submodule controllers according to the connection order of the ring networking are connected by dual links. In the event of a link failure between two submodule controllers, the first network switch switches the connection link between the two submodule controllers to another link.

10. The energy storage system according to any one of claims 1 to 8, characterized in that: The first network switch serves as a communication path between the first main controller and each of the sub-module controllers. In the event of a failure of the first network switch, the first main controller switches the communication path to the second network switch; in the event of a failure of the first main controller, the second main controller takes over the work of the first main controller.

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