Multi-machine grid-connected and off-grid control method for energy storage converter

Abstract

The invention discloses a multi-machine grid-connected and off-grid control method for energy storage converters, and relates to the field of power grid control, and the method comprises the steps: dividing m energy storage converters into n blocks according to the spatial position, setting a common energy storage converter between the same grid-connected and off-grid instruction blocks, and forming a block chain; setting a first energy storage converter and a second energy storage converter in the same block according to the spatial positions of the energy storage converters; according to the actual grid-connected and off-grid requirements and the fault state of the energy storage converter, the block division coverage range is adjusted; the energy storage converter in the block chain is adjusted to compete again to generate a new public energy storage converter; the energy storage converters in the blocks are adjusted to compete again to generate a new first energy storage converter and a new second energy storage converter; and the energy storage converter of the adjusting block part receives the grid-connected and off-grid instruction to perform grid-connected and off-grid so as to realize multi-machine grid-connected and off-grid control of a dynamic region, and the stability and efficiency of multi-machine grid-connected and off-grid instruction transfer are improved.

Description

Technical Field

[0001] This invention relates to the field of power grid control, and more particularly to a method for controlling multiple energy storage converters in parallel and off-grid operation. Background Technology

[0002] To improve the off-grid load-carrying capacity of multi-unit parallel systems, microgrids utilize multiple energy storage converters. "Multiple units" refers to multiple energy storage converters whose grid-connected ports are connected to the grid, and whose off-grid ports are connected together to supply power to the load. Under normal grid conditions, the multiple units operate in parallel, and grid power is transmitted to the off-grid port via relays on each energy storage converter's grid-connected port, supplying power to the load. Under abnormal grid conditions, the energy storage converters supply power to the load through their off-grid ports. Currently, in multi-unit parallel systems, high-speed communication is used between the master and slave units. The master unit sends its operating status, operating mode, and electrical parameters (such as voltage amplitude, phase, frequency, or power) to the slave unit via communication. The slave unit performs synchronous control based on the information sent by the master unit. However, existing multi-unit parallel systems cannot achieve dynamic multi-unit grid-connection and off-grid control according to actual needs.

[0003] Chinese patent document CN202310740240.4 discloses "A multi-machine parallel system and a grid-connected / off-grid control method." This invention involves the main unit switching from a current source to a voltage source based on the amplitude and phase of the voltage at the time of grid disconnection during grid-connection to off-grid switching. The main unit is an inverter or energy storage converter; the slave unit is also an inverter or energy storage converter. Both the main unit's grid-connected port and the slave unit's grid-connected port are used to connect to the power grid. The main unit's off-grid port and the slave unit's off-grid port are connected together to supply power to the load. The slave unit detects the amplitude and phase of the voltage at its off-grid port and switches from a current source to a voltage source based on the detected voltage amplitude and phase. However, this patent cannot achieve multi-machine grid-connected / off-grid control within a dynamic area. Summary of the Invention

[0004] This invention primarily addresses the technical problem of low efficiency in the original multi-unit parallel and off-grid control of energy storage converters within a dynamic area. It provides a method for controlling multiple energy storage converters in parallel and off-grid. Based on actual grid connection and off-grid requirements, the method dynamically defines the block positions of energy storage converters. Within each block, a first energy storage converter is competitively and dynamically designated as the master unit to coordinate with other blocks' energy storage converters. A second energy storage converter is also competitively and dynamically designated as the unit to coordinate grid connection and off-grid synchronization commands within the block. This improves the efficiency of dynamic area adjustment and multi-block grid connection and off-grid control of energy storage converters.

[0005] The above-mentioned technical problems of the present invention are mainly solved by the following technical solutions: The present invention includes S1 dividing n energy storage converters into n blocks according to their spatial location, and setting a common energy storage converter between blocks with the same grid connection and off-grid command.

[0006] S2 sets the first and second energy storage converters in the same block according to their spatial locations.

[0007] S3 adjusts the scope of block division based on actual on / off network requirements;

[0008] S4 adjusts the inter-block energy storage converters to re-compete and generate new common energy storage converters;

[0009] In the S5 adjustment block, the energy storage converters will compete again to generate a new first and second energy storage converter.

[0010] The S6 adjustment block section's energy storage converter is again connected to and disconnected from the grid to achieve dynamic multi-machine grid connection and disconnection control in the region.

[0011] Preferably, after each of the plurality of public energy storage converters completes consensus on a block and adds the block to the blockchain, each of the plurality of public energy storage converters sends a disconnection instruction carrying the block to the first energy storage converter of the corresponding block.

[0012] Preferably, if the first energy storage converter in any of the n blocks receives a grid connection / disconnection instruction, it transmits the grid connection / disconnection instruction to the block it is in and stores it in the blockchain, and sends grid connection / disconnection instructions to adjacent blocks in the same blockchain.

[0013] Preferably, in step S4, the energy storage converters in any block of the adjusted blockchain generate a public energy storage converter through dynamic competition. The blockchain contains at least one public energy storage converter, and the public energy storage converter in any blockchain sends a disconnection command to the corresponding block.

[0014] Preferably, in step S5, any one of the blocks in the adjusted blocks generates a primary energy storage converter through dynamic competition. The other energy storage converters in the block besides the primary energy storage converter are secondary energy storage converters. The primary energy storage converter in the block is the first energy storage converter, and the secondary energy storage converter in the block is the second energy storage converter. The first energy storage converter in any block sends a grid disconnection command to the corresponding energy storage converter.

[0015] Preferably, the energy storage converter has a node table, which includes the node location information of energy storage converters in the same block. If any first energy storage converter in the n blocks receives a grid connection / disconnection instruction, it stores the block carried by the grid connection / disconnection instruction to the blockchain and sends grid connection / disconnection instructions to adjacent energy storage converters in the same block. The energy storage converter in any block performs the following operations: if the received grid connection / disconnection instruction comes from a corresponding public grid connection / disconnection instruction, it adds its own node identifier to the grid connection / disconnection instruction and updates the grid connection / disconnection instruction; it sends the updated grid connection / disconnection instruction to the energy storage converter identified by each node identifier in the node list.

[0016] Preferably, if the grid connection / disconnection command received by the energy storage converter comes from the first energy storage converter in the same block, the node identifier carried by the grid connection / disconnection command is determined as the target node identifier; the grid connection / disconnection command is updated by adding its own node identifier to the grid connection / disconnection command.

[0017] Preferably, each energy storage converter in any block of the n blocks synchronizes its blockchain status with other adjacent energy storage converters in the same block at preset intervals. The blockchain status includes its own node identifier and the block identifier of the latest block in the blockchain. Any energy storage converter in each of the n blocks determines the blockchain status received from adjacent energy storage converters as the target blockchain status. If no blockchain status is received within a preset time period, the energy storage converter is judged to be faulty.

[0018] Preferably, if the energy storage converter failure is a first energy storage converter failure, then the blocks containing the failed first energy storage converter will elect a new first energy storage converter. The energy storage converters in the blocks containing the new first energy storage converter will synchronize their blockchain state to the new first energy storage converter. If the energy storage converter failure is a public energy storage converter failure, then the energy storage converters in the blockchain containing the failed public energy storage converter will elect a new public energy storage converter. The energy storage converters in the blockchain containing the new public energy storage converter will synchronize their blockchain state to the new public energy storage converter.

[0019] Preferably, in step S1, the same blockchain includes a first block and a second block, with the first block linked to the second block. If the original first block fails, the second block in the blockchain containing the original first block will compete to generate a new first block.

[0020] The beneficial effects of this invention are as follows: In this invention, the public energy storage converter corresponds to a corresponding energy storage converter block. The first energy storage converter is the energy storage converter that communicates with the corresponding public energy storage converter. The public energy storage converter only needs to send a grid connection / disconnection command carrying the block to the first energy storage converter in the corresponding energy storage converter block to achieve synchronization of each energy storage converter in the corresponding energy storage converter block with respect to that block, thereby reducing the pressure on the public energy storage converter and improving the block consensus efficiency. Operators only need to issue a grid connection / disconnection command to the public energy storage converter in the first block of the blockchain. The public energy storage converter in the first block will share the command with the first energy storage converters in other blocks to achieve rapid grid connection / disconnection, improving the efficiency of energy storage converter deployment for different regional needs. Furthermore, when the region is divided or the existing energy storage converter fails, the free election of energy storage converters in the block or blockchain can always ensure that the multi-machine parallel and off-grid commands can always be responded to, thus improving the stability and efficiency of the multi-machine parallel and off-grid command mobilization. Attached Figure Description

[0021] Figure 1 This is a flowchart of a multi-machine parallel and off-grid control method according to the present invention.

[0022] Figure 2 This is a flowchart of an energy storage converter selection process according to the present invention. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0024] Example: This example describes a multi-unit parallel-to-off-grid control method for energy storage converters, such as... Figure 1 and Figure 2 As shown, S1 divides m energy storage converters into n blocks according to their spatial location, and sets up common energy storage converters among blocks with the same on-grid and off-grid instructions to form a blockchain;

[0025] S2 sets the first and second energy storage converters in the same block according to their spatial locations.

[0026] S3 adjusts the scope of block division based on actual grid connection and off-grid requirements and the fault status of energy storage converters.

[0027] S4 adjusts the energy storage converters in the blockchain to re-compete and generate new public energy storage converters.

[0028] In the S5 adjustment block, the energy storage converters will compete again to generate a new first and second energy storage converter.

[0029] The S6 adjustment block section's energy storage converter receives and disconnects from the grid, enabling dynamic multi-machine grid connection and disconnection control in the region.

[0030] In the above scheme, each public energy storage converter adds its managed block to the blockchain after completing a scan. The first energy storage converter is the energy storage converter in the same energy storage converter block that communicates with the corresponding public energy storage converter. Only one first energy storage converter exists in the same energy storage converter block. The public energy storage converter sends a grid connection / disconnection command carrying the block to the first energy storage converter in the corresponding energy storage converter block. The grid connection / disconnection command instructs the energy storage converter that receives the command to store the block carried in the command. In this embodiment, the message type of the grid connection / disconnection command is not limited.

[0031] In the above technical solution, several blocks constitute a blockchain. Any public energy storage converter in the blockchain can send a grid connection / disconnection command carrying the block to the corresponding energy storage converter block, so that the corresponding energy storage converter block can obtain the grid connection / disconnection command sharing of the block, thereby ensuring the consistency of command execution by each node in the blockchain. Therefore, the first energy storage converter in any energy storage converter block can store the parameter information of that block. Moreover, any public energy storage converter only needs to send the grid connection / disconnection command to the first energy storage converter in the corresponding energy storage converter block, instead of sending it to every energy storage converter in the corresponding energy storage converter block, thus reducing the pressure on each public energy storage converter. Therefore, before any public energy storage converter sends the grid connection / disconnection command carrying the block to the first energy storage converter in the corresponding energy storage converter block, a first energy storage converter is elected in any energy storage converter block. The first energy storage converter is used to communicate with the corresponding common energy storage converter for grid connection / disconnection commands. That is, the first energy storage converter is the master energy storage converter, and the other energy storage converters in the energy storage converter block besides the master energy storage converter are slave energy storage converters. Therefore, any slave energy storage converter in any energy storage converter block is the second energy storage converter. In other words, an energy storage converter block contains one master energy storage converter and at least one slave energy storage converter.

[0032] In the above technical solution, after any energy storage converter block elects a first energy storage converter, the first energy storage converter in this block can send a grid disconnect command to the corresponding public energy storage converter. The grid disconnect command indicates the primary energy storage converter in the block to which the energy storage converter sending the command has completed its election. The energy storage converter sending the grid disconnect command is the first energy storage converter in its block that communicates with the corresponding public energy storage converter. After the corresponding public energy storage converter adds the block to the blockchain, it can send a grid disconnect command to the first energy storage converter in that block, thus ensuring that the corresponding public energy storage converter can control the energy storage converters in the block. Furthermore, any energy storage converter block can elect a first energy storage converter through a dynamic election process. In this way, when the first energy storage converter elected by the existing energy storage converter block fails, a new first energy storage converter will be elected to ensure that there is always a first energy storage converter in an energy storage converter block communicating with the corresponding public energy storage converter, thereby improving the activity of the energy storage converter block.

[0033] In the above technical solution, the steps for dynamically electing the master energy storage converter in any energy storage converter block within any energy storage converter blockchain are as follows: After the overall startup of an energy storage converter block, each energy storage converter in at least one energy storage converter in this block shares and disconnects from the network with other energy storage converters in the same block; the overall startup of an energy storage converter block means that each energy storage converter in all energy storage converters in this block starts up, that is, each energy storage converter begins to enter the working state; at least one energy storage converter is the energy storage converter in this block that wants to apply to become the first energy storage converter after the overall startup of this energy storage converter block; the node identifier of any energy storage converter is used to uniquely identify this energy storage converter. Since a block of energy storage converters may not contain a primary energy storage converter after its overall startup (i.e., no primary energy storage converter communicating with the corresponding public energy storage converter), the corresponding public energy storage converter, after adding the block to the blockchain, cannot send a disconnection command carrying the block to any energy storage converter in that block. Therefore, an energy storage converter needs to apply to become the primary energy storage converter of this block. During the primary energy storage converter election process, the block receives election messages from other energy storage converters within a preset first time period. This first preset time period can be pre-set and can be set relatively large to ensure that any energy storage converter can receive the election message carrying its own node identifier, shared by each of the other energy storage converters. After sharing the election message, at least one energy storage converter can receive election messages from other energy storage converters to determine which other energy storage converters in this energy storage converter block want to apply to become the main energy storage converter. Any one of the at least one energy storage converter compares its own node identifier with the node identifier carried in the election messages shared by other energy storage converters received within a first preset time period to determine whether it has been elected as the main energy storage converter.

[0034] In the above technical solution, the preset election conditions are used to determine whether a device can be elected as the main energy storage converter. The preset election conditions can be set in advance and can be configured by technicians according to usage requirements. In this embodiment, the preset election conditions can be: the energy storage converter with the smallest node identifier in the energy storage converter block is elected as the main energy storage converter; the energy storage converter with the largest node identifier in the energy storage converter block is elected as the main energy storage converter. If any energy storage converter determines that it has been elected as the first energy storage converter, it resets the preset duration and sends an election message to other energy storage converters in the same energy storage converter block; if it determines that it cannot be elected as the main energy storage converter, it terminates the application to become the main energy storage converter. The reset duration can be preset and can be set to a relatively short duration to ensure that the primary energy storage converter continuously sends election messages to other energy storage converters in the same energy storage converter block. This ensures that the other energy storage converters in the same block always know which energy storage converter is the primary converter. The election message indicates that the energy storage converter sending the election message has been elected as the primary energy storage converter in its block, and also indicates that the energy storage converter receiving the election message is a slave energy storage converter in its block. If any energy storage converter determines that it has been elected as the primary energy storage converter, it sends an election message to the other energy storage converters in the same block to notify them that it has been elected as the primary energy storage converter. At this time, the other energy storage converters in the same block are slave energy storage converters. If it determines that it cannot be elected as the primary energy storage converter, it will end the application process, meaning it will no longer share election information and will withdraw from the primary energy storage converter election. This process ensures that the first energy storage converter for a given energy storage converter block is elected after the block is fully operational.

[0035] In the above technical solution, the campaign message can carry the node identifier of the energy storage converter. If any slave energy storage converter in the energy storage converter block receives an election message, it can compare its own node identifier with the node identifier carried in the election message to determine whether the energy storage converter identified by the node identifier carried in the election message can continue to be elected as the master energy storage converter. If the slave energy storage converter determines that the energy storage converter identified by the node identifier carried in the election message cannot continue to be elected as the master energy storage converter, it sends a request message carrying its own node identifier to the current master energy storage converter. After receiving the request message from the slave energy storage converter, the current master energy storage converter compares its own node identifier with the node identifier carried in the request message to determine whether it can continue to be elected as the master energy storage converter. If the current master energy storage converter determines that it cannot continue to be elected as the master energy storage converter, it sends a confirmation message to the slave energy storage converter. After receiving the confirmation message, the slave energy storage converter determines that it has been elected as the master energy storage converter and shares the election message with other energy storage converters in this energy storage converter block. This request message can be used in the process of applying to become a primary energy storage converter or a public energy storage converter from an energy storage converter.

[0036] In the above technical solution, if each energy storage converter in any energy storage converter block receives a grid connection / disconnection command, it stores the block carried by the grid connection / disconnection command to the blockchain and sends grid connection / disconnection commands to adjacent energy storage converters in the same energy storage converter block. Each energy storage converter can store the block carried by the grid connection / disconnection command to its own blockchain. If the first energy storage converter in any energy storage converter block receives the grid connection / disconnection command sent by the corresponding public energy storage converter, the first energy storage converter can store the block carried by the grid connection / disconnection command to its own blockchain and send grid connection / disconnection commands to adjacent energy storage converters in the same energy storage converter block. Subsequently, upon receiving a grid connection / disconnection command from the first energy storage converter within the same energy storage converter block, any energy storage converter adjacent to the first energy storage converter can store the block carried in the grid connection / disconnection command to its own blockchain and send grid connection / disconnection commands to adjacent energy storage converters within the same energy storage converter block. This process continues, with each energy storage converter within the same energy storage converter block storing the block carried in the grid connection / disconnection command to its own blockchain and sending grid connection / disconnection commands to adjacent energy storage converters within the same energy storage converter block. Furthermore, each energy storage converter within any given energy storage converter block has a node list, which includes the node identifiers of adjacent energy storage converters within the same energy storage converter block.

[0037] In the above technical solution, any public energy storage converter corresponding to an energy storage converter block can generate a check message during the block consensus process. The public energy storage converter can also send this check message to the first energy storage converter in the corresponding energy storage converter block. This check message is used to instruct the energy storage converter to check whether the blocks stored in its own blockchain are correct. The public energy storage converter can generate a check message and send it to the first energy storage converter in the corresponding energy storage converter block in the following two situations: First, after completing consensus on a block, adding the block to the blockchain, and sending a disconnection command carrying the block to the first energy storage converter in the corresponding energy storage converter block, the public energy storage converter can then send the check message to the first energy storage converter in the corresponding energy storage converter block. The first target block identifier carried in this check message is the block identifier of this block. In the above process, before the public energy storage converter sends a grid connection / disconnection command carrying the block to the first energy storage converter in the corresponding energy storage converter block, it sends a check message for that block to the first energy storage converter in the corresponding energy storage converter block. This ensures that each energy storage converter in the corresponding energy storage converter block receives the check message corresponding to that block after storing it, guaranteeing that each energy storage converter can check each block stored in its own blockchain, thereby ensuring the correctness of the blocks stored in its own blockchain. Secondly, after the public energy storage converter completes consensus on a block, adds the block to the blockchain, and sends a grid connection / disconnection command carrying the block to the first energy storage converter in the corresponding energy storage converter block, if the block is executing the corresponding command, the public energy storage converter can then send a check message for that block to the first energy storage converter in the corresponding energy storage converter block. If this block is not being executed, the public energy storage converter may not send a check message for this block to the first energy storage converter in the corresponding energy storage converter block, and may selectively enter the block or blockchain election to elect a new first energy storage converter area or public energy storage converter area. Among the blocks that have completed the check, the block adjacent to multiple blocks is selected as the first block, and the remaining blocks are selected as the second block.

[0038] In the above technical solution, any energy storage converter may be unable to receive blocks for an extended period due to network congestion or network partitioning, thus preventing it from synchronizing with the blocks. In this case, every fourth preset time interval, any energy storage converter sends its blockchain status to adjacent energy storage converters within the same energy storage converter block. This blockchain status includes its own node identifier and the block identifier of the latest block in its blockchain. Any energy storage converter within each energy storage converter block determines the received blockchain status from its adjacent energy storage converters as the target blockchain status. If no block is received within the preset time interval, and the block identifier of the latest block in its own blockchain is less than the block identifier in the target blockchain status, it retrieves a block from the blockchain of the target energy storage converter identified by the node identifier in the target blockchain status, whose block identifier is greater than the block identifier of the latest block in its own blockchain, and stores the retrieved block in its own blockchain. The preset duration can be set in advance, and can also be set by technicians according to requirements. The blockchain state of any energy storage converter represents the status of the latest block stored in its own blockchain. The target blockchain state is the blockchain state received by an energy storage converter from its neighboring energy storage converters. If an energy storage converter has multiple neighboring energy storage converters, then this energy storage converter can receive multiple target blockchain states.

[0039] In the above technical solution, if the target energy storage converter is the energy storage converter identified by the node identifier in the target blockchain state whose block identifier among multiple target blockchain states received by this energy storage converter is greater than the block identifier of the latest block in the blockchain of this energy storage converter, and each energy storage converter in each energy storage converter block sends its blockchain state to other adjacent energy storage converters in the same energy storage converter block at preset intervals, then each energy storage converter can know the status of the latest block stored in the blockchain of its adjacent energy storage converters. If an energy storage converter does not receive a block within a preset time period, it means that the converter has not received blocks for a long time. The converter can then check if any of the multiple target blockchain states has a block identifier larger than the latest block identifier in its own blockchain. If any of the target blockchain states has a block identifier larger than the latest block identifier in its own blockchain, the converter can retrieve the block from the blockchain of the target converter identified by the node identifier of that target blockchain state. This retrieved block is then stored in its own blockchain to synchronize any unstored blocks. If the block identifier in each of the multiple target blockchain states is less than or equal to the latest block identifier in its own blockchain, the converter continues to wait to receive blocks. By using the above method, if an energy storage converter does not receive instructions for a long time, the relevant instructions can be obtained directly from the blockchain of the adjacent target energy storage converter, thereby saving system resources and saving block synchronization time, thus improving block synchronization efficiency.

[0040] In the above technical solution, a new energy storage converter may be added to any energy storage converter block. This new energy storage converter may not yet have any blocks stored. Therefore, the new energy storage converter can synchronize all blocks stored in the blockchains of other energy storage converters in its block. The new energy storage converter can execute the steps described above to obtain all instructions from the target energy storage converter, thereby synchronizing the blocks stored in the blockchains of other energy storage converters in its block. When any energy storage converter in each block discovers that its own blockchain is missing some blocks, it actively obtains all the missing blocks from the target energy storage converter, synchronizing all the missing blocks, thus saving system resources and improving block synchronization efficiency. Any blockchain comprises multiple public energy storage converters and several energy storage converter blocks. Each public energy storage converter corresponds to a specific energy storage converter block, and each energy storage converter block includes a first energy storage converter and at least one second energy storage converter. The first energy storage converter communicates with the corresponding public energy storage converter. The public energy storage converter only needs to send a connection / disconnection command carrying the block to the first energy storage converter in the corresponding energy storage converter block to achieve synchronization of each energy storage converter in that block with respect to the block. This reduces the pressure on the public energy storage converter and thus improves the block consensus efficiency. Therefore, in actual multi-unit grid connection and disconnection control of multiple energy storage converters, operators only need to issue grid connection and disconnection commands to the public energy storage converter in the first block of the blockchain. The public energy storage converter in the first block will share this command with the first energy storage converters in other blocks to achieve rapid grid connection and disconnection, improving the efficiency of energy storage converter deployment for different regional needs. Furthermore, when regional divisions or existing energy storage converters fail, the free election of energy storage converters within blocks or the blockchain ensures that multi-unit grid connection and disconnection commands are always responded to, improving the stability and efficiency of multi-unit grid connection and disconnection command deployment.

Claims

1. A method for controlling multiple parallel-to-off-grid energy storage converters, characterized in that, include S1 divides m energy storage converters into n blocks according to their spatial location, and sets up common energy storage converters among blocks with the same grid connection and off-grid instructions to form a blockchain; S2 sets the first and second energy storage converters in the same block according to their spatial locations. S3 adjusts the scope of block division based on actual grid connection and off-grid requirements and the fault status of energy storage converters. S4 adjusts the energy storage converters in the blockchain to re-compete and generate new public energy storage converters. In the S5 adjustment block, the energy storage converters will compete again to generate a new first and second energy storage converter. The S6 adjustment block section's energy storage converter receives and disconnects from the grid, enabling dynamic multi-machine grid connection and disconnection control in the region.

2. The method for multi-unit parallel-off-grid control of energy storage converters according to claim 1, characterized in that, After each of the plurality of public energy storage converters completes consensus on a block and adds the block to the blockchain, each of the plurality of public energy storage converters sends a disconnection instruction carrying the block to the first energy storage converter of the corresponding block.

3. The method for multi-unit parallel-off-grid control of energy storage converters according to claim 2, characterized in that, If the first energy storage converter in any of the n blocks receives a grid connection / disconnection instruction, it will transmit the grid connection / disconnection instruction to the block it is in and store it in the blockchain, and send grid connection / disconnection instructions to adjacent blocks in the same blockchain.

4. The multi-unit parallel-off-grid control method for energy storage converters according to claim 2, characterized in that, In step S4, the energy storage converters in any block of the adjusted blockchain generate a public energy storage converter through dynamic competition. The blockchain contains at least one public energy storage converter, and the public energy storage converter in any blockchain sends a disconnection command to the corresponding block.

5. A multi-unit parallel-off-grid control method for energy storage converters according to claim 4, characterized in that, In step S5, any one of the adjusted blocks generates a primary energy storage converter through dynamic competition. Other energy storage converters in the block besides the primary energy storage converter are secondary energy storage converters. The primary energy storage converter in the block is the first energy storage converter, and the secondary energy storage converter in the block is the second energy storage converter. The first energy storage converter in any block sends a grid disconnection command to the corresponding energy storage converter.

6. The method for multi-unit parallel-off-grid control of energy storage converters according to claim 1, characterized in that, The energy storage converter has a node table, which includes the node location information of energy storage converters in the same block. If any first energy storage converter in the n blocks receives a grid connection / disconnection instruction, it stores the block carried by the grid connection / disconnection instruction to the blockchain and sends grid connection / disconnection instructions to adjacent energy storage converters in the same block. The energy storage converter in any block performs the following operations: if the received grid connection / disconnection instruction comes from the corresponding public grid connection / disconnection instruction, it adds its own node identifier to the grid connection / disconnection instruction and updates the grid connection / disconnection instruction; it sends the updated grid connection / disconnection instruction to the energy storage converter identified by each node identifier in the node list.

7. A multi-unit parallel-off-grid control method for energy storage converters according to claim 6, characterized in that, If the grid connection / offline command received by the energy storage converter comes from the first energy storage converter in the same block, the node identifier carried by the grid connection / offline command will be determined as the target node identifier. Add its own node identifier to the disconnect / disconnect command to update the disconnect / disconnect command.

8. A multi-unit parallel-off-grid control method for energy storage converters according to claim 4, characterized in that, Each energy storage converter in any of the n blocks synchronizes its blockchain status with other adjacent energy storage converters in the same block at preset time intervals. The blockchain status includes its own node identifier and the block identifier of the latest block in the blockchain. Any energy storage converter in each of the n blocks determines the blockchain status received from adjacent energy storage converters as the target blockchain status. If no blockchain status is received within the preset time, the energy storage converter is judged to be faulty.

9. A multi-unit parallel-off-grid control method for energy storage converters according to claim 7, characterized in that, If the energy storage converter failure is a first energy storage converter failure, then the blocks containing the failed first energy storage converter will elect a new first energy storage converter. The energy storage converters in the blocks containing the new first energy storage converter will synchronize their blockchain state to the new first energy storage converter. If the energy storage converter failure is a public energy storage converter failure, then the energy storage converters in the blockchain containing the failed public energy storage converter will elect a new public energy storage converter. The energy storage converters in the blockchain containing the new public energy storage converter will synchronize their blockchain state to the new public energy storage converter.

10. A multi-unit parallel-off-grid control method for energy storage converters according to claim 8, characterized in that, In step S1, the same blockchain includes a first block and a second block. The first block is connected to the second block. If the original first block fails, the second block in the blockchain containing the original first block will compete to generate a new first block.

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