Energy storage off-grid parallel operation method and energy storage off-grid parallel operation system

Abstract

The invention discloses an energy storage off-grid parallel operation method and an energy storage off-grid parallel operation system, the energy storage off-grid parallel operation system comprises a signal module and a plurality of energy storage units, and each energy storage unit is correspondingly provided with a relay interlocking module; each relay interlocking module is connected with the off-grid relay and the grid-connected relay in the corresponding energy storage unit and is used for controlling mutual exclusion of the grid-connected relay and the off-grid relay in the same energy storage unit; the signal module is connected between each energy storage unit and each relay interlocking module; the energy storage off-grid parallel operation method comprises the following steps: after the signal module receives a grid-connected signal or an off-grid signal sent by any energy storage unit in the energy storage off-grid parallel operation system, all the relay interlocking modules are controlled to act at the same time so as to switch a grid-connected working mode or an off-grid working mode of the energy storage unit. According to the energy storage off-grid parallel operation method, it can be ensured that the energy storage units enter the grid-connected working mode or the off-grid working mode at the same time point.

Description

Technical Field

[0001] The present invention belongs to the technical field of off-grid and grid-connected control, and in particular relates to an energy storage off-grid and grid-connected parallel method and an energy storage off-grid and grid-connected parallel system based on the energy storage off-grid and grid-connected parallel method. Background Art

[0002] In existing off-grid parallel energy storage systems, the off-grid ports of multiple units must be connected in parallel. The on-grid to off-grid transition relies on the opening and closing of relays. Due to the large timing errors between the opening and closing of relays, it is impossible to guarantee that all units will be disconnected from the grid simultaneously. This can lead to some energy storage units being in on-grid mode while others are in off-grid mode. This means that the same off-grid parallel energy storage system can operate in both on-grid and off-grid modes simultaneously, causing system downtime and even equipment failure.

[0003] To address this issue, the currently widely used solution is to control relay logic through the energy storage system's DSP software. However, this solution has significant drawbacks. External hardware or software interference can cause software control logic failure or delays, making it impossible to effectively ensure that the entire off-grid parallel energy storage system operates in the same mode.

[0004] That is, the existing solution is to use the software inside the energy storage unit to independently control the working mode of a single energy storage system. Figure 1 As shown in the figure, taking two energy storage units as an example, each unit independently controls its corresponding grid-connected relay and off-grid relay. However, the relays of the two energy storage units cannot achieve mode synchronization. Especially when the energy storage units are in complex environments or are subject to software delays and hardware interference, the two independent energy storage units cannot guarantee that they are in the same operating mode. Inevitably, one energy storage unit operates in grid-connected mode while the other operates in off-grid mode, which inevitably leads to the risk of system downtime or explosion.

[0005] Patent application number 202111422838.6 adds an external "fourth control unit" to address the issue of insufficient load-carrying capacity when operating in parallel. Patent application number 202410540045.1 employs software to control the grid-connected system's slaves, allowing them to be controlled and monitored by the master. This represents a system software control logic solution. However, none of these patents address the issue of asynchronous switching between grid-connected and off-grid operating modes for multiple energy storage units.

[0006] Therefore, existing solutions that independently control the operating mode of individual energy storage systems still carry the risk of system downtime or explosion. Therefore, there is an urgent need for an off-grid parallel energy storage method and system that can effectively ensure that each independent energy storage unit can enter grid-connected mode simultaneously.

[0007] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention. It does not necessarily belong to the prior art of the present invention. In the absence of clear evidence showing that the above content has been disclosed before the application date of the present invention, the above background technology should not be used to evaluate the novelty and creativity of the present invention. Summary of the Invention

[0008] In view of this, in order to overcome the defects of the prior art, the purpose of the present invention is to provide an energy storage off-grid parallel operation method to ensure that all energy storage units can enter the grid-connected working mode or the off-grid working mode at the same time.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions: A method for off-grid energy storage and parallel operation, wherein the off-grid energy storage and parallel operation system comprises a signal module and a plurality of energy storage units, wherein each energy storage unit is provided with a corresponding relay interlocking module; each relay interlocking module is connected to an off-grid relay and a grid-connected relay in a corresponding energy storage unit, and is used to control the grid-connected relay and the off-grid relay in the same energy storage unit to mutually exclude each other; the signal module is connected between each energy storage unit and each relay interlocking module, and is used to control the operation of the relay interlocking module according to the status of the energy storage unit; The energy storage off-grid parallel method comprises the following steps: After receiving a grid-connected or off-grid signal from any energy storage unit in the off-grid parallel energy storage system, the signal module controls all relay interlock modules to operate simultaneously to switch between grid-connected and off-grid operating modes. In the present invention, the mutual exclusion of relays in the same energy storage unit means that at the same moment, one of the grid-connected relay and the off-grid relay is disconnected and the other is closed.

[0010] According to some preferred implementation aspects of the present invention, after the signal module receives the grid-connected signal sent by any energy storage unit in the energy storage off-grid parallel system, it controls the operation of all relay interlocking modules, disconnects the off-grid relays of all energy storage units, and simultaneously closes the grid-connected relays of all energy storage units, so that all energy storage units enter the grid-connected working mode at the same time.

[0011] According to some preferred implementation aspects of the present invention, when all energy storage units in the energy storage off-grid parallel system are in the off-grid working mode, when any one of the energy storage units switches to the grid-connected working mode, the energy storage unit transmits the grid-connected signal to the signal module. After receiving the grid-connected signal, the signal module sends a grid-connected instruction to all relay interlocking modules. After receiving the grid-connected instruction, all relay interlocking modules disconnect the off-grid relay and close the grid-connected relay at the same time, so that all energy storage units enter the grid-connected working mode at the same time.

[0012] According to some preferred implementation aspects of the present invention, after the signal module receives the off-grid signal sent by any energy storage unit in the off-grid parallel energy storage system, it controls the actions of all relay interlocking modules, disconnects the grid-connected relays of all energy storage units, and simultaneously closes the off-grid relays of all energy storage units, so that all energy storage units enter the off-grid working mode at the same time.

[0013] According to some preferred implementation aspects of the present invention, when all energy storage units in the energy storage off-grid parallel system are in the grid-connected working mode, when any one of the energy storage units switches to the off-grid working mode, the energy storage unit transmits an off-grid signal to the signal module. After receiving the off-grid signal, the signal module sends an off-grid instruction to all relay interlocking modules. After receiving the off-grid instruction, all relay interlocking modules disconnect the grid-connected relay and close the off-grid relay at the same time, so that all energy storage units enter the off-grid working mode at the same time.

[0014] That is, the energy storage unit has an off-grid working mode and a grid-connected working mode: in the off-grid working mode, the off-grid relay is closed and the grid-connected relay is disconnected; in the grid-connected working mode, the grid-connected relay is closed and the off-grid relay is disconnected.

[0015] According to some preferred embodiments of the present invention, the signal module includes a signal bus and a NOR gate arranged between the signal bus and the energy storage unit, the input end of the NOR gate is connected to the energy storage unit, and the output end of the NOR gate is connected to the signal bus.

[0016] According to some preferred embodiments of the present invention, each of the energy storage units includes an energy storage module, the off-grid relay, the grid-connected relay, a grid-connected port and the relay interlock module; the energy storage module, the off-grid relay, the grid-connected relay and the grid-connected port are arranged in sequence; and the signal bus is connected between the energy storage module and the relay interlock module.

[0017] According to some preferred embodiments of the present invention, the energy storage module has an off-grid state corresponding to the off-grid operating mode of the energy storage unit and a grid-connected state corresponding to the grid-connected operating mode of the energy storage unit. When the signal bus sends an off-grid instruction to all relay interlock modules, it also sends a corresponding off-grid instruction to all energy storage modules, and all energy storage modules simultaneously switch to the off-grid state. Similarly, when the signal bus sends a grid-connected instruction to all relay interlock modules, it also sends a corresponding grid-connected instruction to all energy storage modules, and all energy storage modules simultaneously switch to the grid-connected state.

[0018] According to some preferred implementation aspects of the present invention, the relay interlock module includes a first control circuit for controlling the off-grid relay and a second control circuit for controlling the grid-connected relay, and both the first control circuit and the second control circuit are connected to a signal bus.

[0019] According to some preferred implementation aspects of the present invention, a NOT gate is provided on the second control circuit to control the off-grid relay and the grid-connected relay to be mutually exclusive.

[0020] According to some preferred implementation aspects of the present invention, the off-grid relay is arranged close to the energy storage module, and the grid-connected relay is arranged close to the grid-connected port, that is, the energy storage module, the off-grid relay, the grid-connected relay, and the grid-connected port are arranged in sequence.

[0021] According to some preferred embodiments of the present invention, the energy storage off-grid parallel system includes an off-grid port connected between an off-grid relay and a grid-connected relay of each energy storage unit. The grid-connected port is used to connect to the AC grid, and the off-grid port is used to connect to a load.

[0022] The present invention also provides an energy storage off-grid parallel system based on the above energy storage off-grid parallel method.

[0023] Due to the adoption of the above technical solution, compared with the prior art, the benefits of the present invention are as follows: the energy storage off-grid parallel method of the present invention sets a relay interlocking module corresponding to each energy storage unit, so that the off-grid relay and the grid-connected relay in each energy storage unit are mutually exclusive, and at the same time, a signal module connected to the signals of each energy storage unit and each relay interlocking module is set, which is used to receive the signal of any energy storage unit and can send instructions to all relay interlocking modules at the same time, thereby ensuring that the energy storage units enter the grid-connected working mode or the off-grid working mode at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 It is a structural diagram of a parallel system in the prior art; Figure 2 This is a structural diagram of an off-grid parallel energy storage system in a preferred embodiment of the present invention; the dotted arrows in the figure indicate the direction of current flow; In the accompanying drawings, the reference numerals include: energy storage module-1, signal module-2, signal bus-21, NOR gate-22, relay interlock module-3, first control circuit-31, second control circuit-32, NOR gate-33, off-grid relay-41, grid-connected relay-42, grid-connected port-51, off-grid port-52. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0027] like Figure 2 As shown, the energy storage off-grid parallel system of the present invention includes a signal module 2, multiple energy storage units and an off-grid port 52. Each energy storage unit includes an energy storage module 1, an off-grid relay 41, a grid-connected relay 42, a grid-connected port 51 and a relay interlocking module 3. The off-grid relay 41 is arranged close to the energy storage module 1, and the grid-connected relay 42 is arranged close to the grid-connected port 51, that is, the energy storage module 1, the off-grid relay 41, the grid-connected relay 42 and the grid-connected port 51 are arranged in sequence. The off-grid port 52 is connected between the off-grid relay 41 and the grid-connected relay 42 of each energy storage unit. The grid-connected port 51 is used to connect to the AC power grid, and the off-grid port 52 is used to connect to the load. Through the signal module 2 and the relay interlocking module 3, the energy storage off-grid parallel system of the present invention can realize the synchronous action of the relays of multiple energy storage units, and then control all energy storage units to enter the grid-connected working mode or the off-grid working mode at the same time.

[0028] Each relay interlock module 3 is connected to the off-grid relay 41 and grid-connected relay 42 in the corresponding energy storage unit, controlling the mutual exclusion of the grid-connected relay 42 and off-grid relay 41 in the same energy storage unit. In the present invention, mutual exclusion of relays in the same energy storage unit means that at the same moment, one of the grid-connected relay 42 and off-grid relay 41 is disconnected and the other is closed. A signal module 2 is connected between each energy storage unit and each relay interlock module 3.

[0029] Specifically, the signal module 2 in the present invention includes a signal bus 21 and a NOR gate 22 disposed between the signal bus 21 and the energy storage unit. The input of the NOR gate 22 is connected to the energy storage module 1, and the output of the NOR gate 22 is connected to the signal bus 21. Simultaneously, the signal bus 21 is connected between the energy storage module 1 and the relay interlock module 3, and is configured to simultaneously receive signals from each independent energy storage unit and send system instructions to each independent relay interlock module 3 and energy storage module 1. The relay interlock module 3 receives the instructions and operates, achieving hardware synchronous switching. The energy storage module 1 receives the instructions and switches its state, achieving software signal synchronization.

[0030] The energy storage unit has an off-grid working mode and a grid-connected working mode: in the off-grid working mode, the off-grid relay 41 is closed and the grid-connected relay 42 is disconnected; in the grid-connected working mode, the grid-connected relay 42 is closed and the off-grid relay 41 is disconnected. The energy storage module 1 has an off-grid state corresponding to the off-grid working mode of the energy storage unit and a grid-connected state corresponding to the grid-connected working mode of the energy storage unit. When the signal bus 21 sends an off-grid instruction to all relay interlock modules 3, it also sends a corresponding off-grid instruction to all energy storage modules 1, and all energy storage modules 1 switch to the off-grid state at the same time. Similarly, when the signal bus 21 sends a grid-connected instruction to all relay interlock modules 3, it also sends a corresponding grid-connected instruction to all energy storage modules 1, and all energy storage modules 1 switch to the grid-connected state at the same time.

[0031] That is, in addition to being connected via NOR gate 22, signal bus 21 and energy storage module 1 of the present invention also require a direct connection between the two, allowing energy storage module 1 to directly receive feedback instructions from signal bus 21. After receiving the signal from energy storage module 1 via NOR gate 22, signal bus 21 simultaneously issues instructions to relay interlock module 3 and energy storage module 1. Relay interlock module 3 receives the instructions to control relay operation to achieve hardware synchronization switching, while energy storage module 1 receives the instructions to control its state switching to achieve software signal synchronization.

[0032] The relay interlock module 3 includes a first control circuit 31 for controlling the off-grid relay 41 and a second control circuit 32 for controlling the grid-connected relay 42. Both the first control circuit 31 and the second control circuit 32 are connected to the signal bus 21 and are used to control the opening and closing of the grid-connected relay 42 and the off-grid relay 41. The second control circuit 32 is provided with a NOT gate 33 to control the mutual exclusion of the off-grid relay 41 and the grid-connected relay 42, that is, to ensure that only one of them is closed at a time and the other is open.

[0033] An energy storage off-grid parallel method based on the above energy storage off-grid parallel system of the present invention comprises the following steps: After receiving the grid-connected signal or off-grid signal sent by any energy storage unit in the energy storage off-grid parallel system, the signal module 2 controls all the relay interlock modules 3 to operate simultaneously to switch the grid-connected working mode or off-grid working mode of the energy storage unit.

[0034] In some embodiments, after the signal module 2 receives the grid-connected signal sent by any energy storage unit in the energy storage off-grid parallel system, it controls all relay interlocking modules 3 to operate, disconnect the off-grid relays 41 of all energy storage units, and simultaneously close the grid-connected relays 42 of all energy storage units, so that all energy storage units enter the grid-connected working mode at the same time.

[0035] Specifically, when all energy storage units in the energy storage off-grid parallel system are in the off-grid working mode, when any one of the energy storage units switches to the grid-connected working mode, the energy storage unit transmits the grid-connected signal to the signal module 2. After receiving the grid-connected signal, the signal module 2 sends a grid-connected instruction to all relay interlocking modules 3. After all relay interlocking modules 3 receive the grid-connected instruction, they disconnect the off-grid relay 41 and close the grid-connected relay 42 at the same time, so that all energy storage units enter the grid-connected working mode at the same time.

[0036] More specifically, when all energy storage units in the off-grid parallel energy storage system are in the off-grid working mode and all energy storage modules 1 are in the off-grid state, when any one of the energy storage units switches to the grid-connected working mode, the corresponding energy storage module 1 switches to the grid-connected state. The energy storage module 1 transmits the grid-connected signal to the signal bus 21 through the NOR gate 22 of the signal module 2. After receiving the grid-connected signal, the signal bus 21 sends a grid-connected instruction to all relay interlocking modules 3 and all energy storage modules 1. After receiving the grid-connected instruction, all relay interlocking modules 3 disconnect the off-grid relay 41 and close the grid-connected relay 42 at the same time, realizing hardware synchronous switching; at the same time, all energy storage modules 1 switch to the grid-connected state at the same time after receiving the grid-connected instruction, realizing software signal synchronization, and thus realizing that all energy storage units enter the grid-connected working mode at the same time.

[0037] In other embodiments, after the signal module 2 receives the off-grid signal sent by any energy storage unit in the energy storage off-grid parallel system, it controls all the relay interlocking modules 3 to operate, disconnects the grid-connected relays 42 of all energy storage units, and simultaneously closes the off-grid relays 41 of all energy storage units, so that all energy storage units enter the off-grid working mode at the same time.

[0038] Specifically, when all energy storage units in the energy storage off-grid parallel system are in the grid-connected working mode, when any one of the energy storage units switches to the off-grid working mode, the energy storage unit transmits the off-grid signal to the signal module 2. After receiving the off-grid signal, the signal module 2 sends an off-grid instruction to all relay interlocking modules 3. After all relay interlocking modules 3 receive the off-grid instruction, they disconnect the grid-connected relay 42 and close the off-grid relay 41 at the same time, so that all energy storage units enter the off-grid working mode at the same time.

[0039] More specifically, when all energy storage units in the off-grid parallel energy storage system are in the grid-connected working mode and all energy storage modules 1 are in the grid-connected state, when any one of the energy storage units switches to the off-grid working mode, the corresponding energy storage module 1 switches to the off-grid state. The energy storage module 1 transmits the off-grid signal to the signal bus 21 through the NOR gate 22 of the signal module 2. After receiving the off-grid signal, the signal bus 21 sends an off-grid instruction to all relay interlocking modules 3 and all energy storage modules 1. After receiving the off-grid instruction, all relay interlocking modules 3 disconnect the grid-connected relay 42 and close the off-grid relay 41 at the same time, realizing hardware synchronous switching; at the same time, all energy storage modules 1 switch to the off-grid state at the same time after receiving the off-grid instruction, realizing software signal synchronization, and thus realizing that all energy storage units enter the off-grid working mode at the same time.

[0040] Example 1: Figure 2 As shown, the energy storage off-grid parallel system of this embodiment includes a signal module 2, multiple energy storage units, and an off-grid port 52. Each energy storage unit includes an energy storage module 1, an off-grid relay 41, a grid-connected relay 42, a grid-connected port 51, and a relay interlock module 3. The off-grid relay 41 is located near the energy storage module 1, and the grid-connected relay 42 is located near the grid-connected port 51. That is, the energy storage module 1, the off-grid relay 41, the grid-connected relay 42, and the grid-connected port 51 are located in this order. The off-grid port 52 is connected between the off-grid relay 41 and the grid-connected relay 42 of each energy storage unit. The grid-connected port 51 is used to connect to the AC grid, and the off-grid port 52 is used to connect to the load.

[0041] Each relay interlock module 3 is connected to the off-grid relay 41 and the grid-connected relay 42 in the corresponding energy storage unit, and is used to control the mutual exclusion of the grid-connected relay 42 and the off-grid relay 41 in the same energy storage unit. The signal module 2 is signal-connected to each energy storage unit and each relay interlock module 3. Specifically, the signal module 2 includes a signal bus 21 and a NOR gate 22 arranged between the signal bus 21 and the energy storage module 1. The input end of the NOR gate 22 is connected to the energy storage module 1, and the output end of the NOR gate 22 is connected to the signal bus 21. The signal bus 21 is connected between the energy storage module 1 and the relay interlock module 3, and is used to simultaneously receive the signal of each independent energy storage unit and send system instructions to each independent relay interlock module 3 and energy storage module 1. The relay interlock module 3 receives the instruction and acts to realize hardware synchronous switching. The energy storage module 1 receives the instruction and switches the state to realize software signal synchronization.

[0042] The relay interlock module 3 in this embodiment includes a first control circuit 31 for controlling an off-grid relay 41 and a second control circuit 32 for controlling a grid-connected relay 42. Both the first control circuit 31 and the second control circuit 32 are connected to the signal bus 21 and are used to control the opening and closing of the grid-connected relay 42 and the off-grid relay 41. The second control circuit 32 is provided with a NOT gate 33 to control the mutual exclusion of the off-grid relay 41 and the grid-connected relay 42, that is, to ensure that only one of them is closed at a time and the other is open.

[0043] Example 2: This example provides an off-grid energy storage parallel method based on the above-mentioned off-grid energy storage parallel system, so as to achieve synchronous switching of all energy storage units from an off-grid operating mode to a grid-connected operating mode, including the following steps: When any energy storage unit in the energy storage off-grid parallel system switches to the grid-connected working mode, the energy storage unit transmits the grid-connected signal to the signal module 2. After receiving the grid-connected signal, the signal module 2 sends the grid-connected instruction to all relay interlocking modules 3. After all relay interlocking modules 3 receive the grid-connected instruction, they disconnect the off-grid relay 41 and close the grid-connected relay 42 at the same time, so that all energy storage units enter the grid-connected working mode at the same time.

[0044] Based on the component structure of the energy storage off-grid parallel system in Example 1, the energy storage off-grid parallel method for switching from an off-grid operating mode to a grid-connected operating mode in this embodiment specifically includes the following steps: When all energy storage units in the off-grid parallel energy storage system are in off-grid working mode and all energy storage modules 1 are in off-grid state, when any energy storage unit switches to the grid-connected working mode, the corresponding energy storage module 1 switches to the grid-connected state. The energy storage module 1 transmits the grid-connected signal to the signal bus 21 through the NOR gate 22 of the signal module 2. After receiving the grid-connected signal, the signal bus 21 sends a grid-connected instruction to all relay interlocking modules 3 and all energy storage modules 1. After receiving the grid-connected instruction, all relay interlocking modules 3 control the off-grid relay 41 and the grid-connected relay 42 to be mutually exclusive through the NOR gate 33 on the first control circuit 31 and the second control circuit 32, that is, the off-grid relay 41 is disconnected and the grid-connected relay 42 is closed at the same time, realizing hardware synchronous switching; at the same time, all energy storage modules 1 switch to the grid-connected state at the same time after receiving the grid-connected instruction, realizing software signal synchronization, and thus realizing that all energy storage units enter the grid-connected working mode at the same time.

[0045] Example 3: This example provides an off-grid energy storage parallel method based on the above-mentioned off-grid energy storage parallel system, which enables the energy storage unit to switch from a grid-connected working mode to an off-grid working mode, including the following steps: When any energy storage unit in the energy storage off-grid parallel system switches to the off-grid working mode, the energy storage unit transmits the off-grid signal to the signal module 2. After receiving the off-grid signal, the signal module 2 sends an off-grid instruction to all relay interlocking modules 3. After all relay interlocking modules 3 receive the off-grid instruction, they disconnect the grid-connected relay 42 and close the off-grid relay 41 at the same time, so that all energy storage units enter the off-grid working mode at the same time.

[0046] Based on the component structure of the energy storage off-grid parallel system in Example 1, the energy storage off-grid parallel method for switching from a grid-connected working mode to an off-grid working mode in this embodiment specifically includes the following steps: When all energy storage units in the off-grid parallel energy storage system are in the grid-connected working mode and all energy storage modules 1 are in the grid-connected state, when any energy storage unit switches to the off-grid working mode, the corresponding energy storage module 1 switches to the off-grid state. The energy storage module 1 transmits the off-grid signal to the signal bus 21 through the OR gate 22 of the signal module 2. After receiving the off-grid signal, the signal bus 21 sends an off-grid instruction to all relay interlocking modules 3 and all energy storage modules 1. After receiving the off-grid instruction, all relay interlocking modules 3 control the off-grid relay 41 and the grid-connected relay 42 to be mutually exclusive through the NOT gate 33 on the first control circuit 31 and the second control circuit 32, that is, disconnect the grid-connected relay 42 and close the off-grid relay 41 at the same time, realizing hardware synchronous switching; at the same time, all energy storage modules 1 switch to the off-grid state at the same time after receiving the off-grid instruction, realizing software signal synchronization, and thus realizing that all energy storage units enter the off-grid working mode at the same time.

[0047] The energy storage off-grid parallel method of the present invention sets a relay interlocking module 3 corresponding to each energy storage unit, so that the off-grid relay 41 and the grid-connected relay 42 in each energy storage unit are mutually exclusive. At the same time, a signal module 2 is set that is signal-connected to each energy storage unit and each relay interlocking module 3. After the signal module 2 receives the grid-connected signal or the off-grid signal sent by any energy storage unit in the energy storage off-grid parallel system, it controls the action of all the relay interlocking modules 3 to switch between the grid-connected working mode and the off-grid working mode, thereby ensuring that all the energy storage units enter the grid-connected working mode or the off-grid working mode at the same time. Specifically, after the signal module 2 receives a grid-connected signal sent by any energy storage unit in the off-grid parallel energy storage system, it controls all relay interlock modules 3 to operate, disconnecting the off-grid relays 41 of all energy storage units and simultaneously closing the grid-connected relays 42 of all energy storage units, thereby enabling all energy storage units to enter the grid-connected working mode at the same time; or, after the signal module 2 receives an off-grid signal sent by any energy storage unit in the off-grid parallel energy storage system, it controls all relay interlock modules 3 to operate, disconnecting the grid-connected relays 42 of all energy storage units and simultaneously closing the off-grid relays 41 of all energy storage units, thereby enabling all energy storage units to enter the off-grid working mode at the same time. While the relay interlock module 3 receives the instruction and operates, the energy storage module 1 also receives the instruction from the signal module 2 to switch the state, thereby simultaneously achieving software and hardware switching.

[0048] The above-described embodiments, prepared by the methods of the present invention, are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent variations or modifications made in accordance with the spirit and substance of the present invention are intended to be encompassed within the scope of protection of the present invention.

Claims

1. A method for off-grid parallel operation of energy storage, characterized in that: The energy storage off-grid parallel system includes a signal module and multiple energy storage units, each of which is provided with a corresponding relay interlocking module; each relay interlocking module is connected to the off-grid relay and the grid-connected relay in the corresponding energy storage unit, and is used to control the mutual exclusion of the grid-connected relay and the off-grid relay in the same energy storage unit; the signal module is connected between each energy storage unit and each relay interlocking module; The energy storage off-grid parallel method comprises the following steps: After receiving the grid-connected signal or off-grid signal sent by any energy storage unit in the energy storage off-grid parallel system, the signal module controls all relay interlock modules to operate simultaneously to switch the grid-connected working mode or off-grid working mode of the energy storage unit.

2. The energy storage off-grid parallel method according to claim 1, characterized in that: After receiving the grid-connected signal sent by any energy storage unit in the energy storage off-grid parallel system, the signal module controls the operation of all relay interlocking modules, disconnects the off-grid relays of all energy storage units, and simultaneously closes the grid-connected relays of all energy storage units, so that all energy storage units enter the grid-connected working mode at the same time.

3. The energy storage off-grid parallel method according to claim 1 or 2, characterized in that: When all energy storage units in the energy storage off-grid parallel system are in the off-grid working mode, when any one of the energy storage units switches to the grid-connected working mode, the energy storage unit transmits the grid-connected signal to the signal module. After receiving the grid-connected signal, the signal module sends a grid-connected instruction to all relay interlocking modules. After receiving the grid-connected instruction, all relay interlocking modules disconnect the off-grid relay and close the grid-connected relay at the same time, so that all energy storage units enter the grid-connected working mode at the same time.

4. The energy storage off-grid parallel method according to claim 1, characterized in that: After receiving the off-grid signal sent by any energy storage unit in the off-grid parallel energy storage system, the signal module controls the actions of all relay interlock modules, disconnects the grid-connected relays of all energy storage units, and simultaneously closes the off-grid relays of all energy storage units, so that all energy storage units enter the off-grid working mode at the same time.

5. The energy storage off-grid parallel method according to claim 1 or 4, characterized in that: When all energy storage units in the energy storage off-grid parallel system are in the grid-connected working mode, when any one of the energy storage units switches to the off-grid working mode, the energy storage unit transmits an off-grid signal to the signal module. After receiving the off-grid signal, the signal module sends an off-grid instruction to all relay interlocking modules. After receiving the off-grid instruction, all relay interlocking modules disconnect the grid-connected relay and close the off-grid relay at the same time, so that all energy storage units enter the off-grid working mode at the same time.

6. The energy storage off-grid parallel method according to claim 1, characterized in that: The signal module includes a signal bus and a NOR gate arranged between the signal bus and the energy storage unit, the input end of the NOR gate is connected to the energy storage unit, and the output end of the NOR gate is connected to the signal bus.

7. The energy storage off-grid parallel method according to claim 6, characterized in that: Each of the energy storage units includes an energy storage module, the off-grid relay, the grid-connected relay, a grid-connected port and the relay interlocking module; the signal bus is connected between the energy storage module and the relay interlocking module.

8. The energy storage off-grid parallel method according to claim 6, characterized in that: The relay interlock module includes a first control circuit for controlling the off-grid relay and a second control circuit for controlling the grid-connected relay, and both the first control circuit and the second control circuit are connected to a signal bus.

9. The energy storage off-grid parallel method according to claim 8, characterized in that: The second control circuit is provided with a NOT gate.

10. The energy storage off-grid parallel method according to claim 7, characterized in that: The energy storage module has an off-grid state corresponding to the off-grid working mode of the energy storage unit and a grid-connected state corresponding to the grid-connected working mode of the energy storage unit; when the signal bus sends an off-grid instruction to all relay interlocking modules, it also sends a corresponding off-grid instruction to all energy storage modules, and all energy storage modules switch to the off-grid state at the same time; when the signal bus sends a grid-connected instruction to all relay interlocking modules, it also sends a corresponding grid-connected instruction to all energy storage modules, and all energy storage modules switch to the grid-connected state at the same time.

11. The energy storage off-grid parallel method according to claim 7, characterized in that: The off-grid relay is arranged close to the energy storage module, and the grid-connected relay is arranged close to the grid-connected port.

12. The energy storage off-grid parallel method according to claim 7, characterized in that: The energy storage off-grid parallel system includes an off-grid port, which is connected between the off-grid relay and the grid-connected relay of each energy storage unit.

13. An off-grid energy storage parallel system based on the off-grid energy storage parallel method according to any one of claims 1 to 12.

Images