Micro-grid environment flow battery system and control method thereof

Abstract

The invention discloses a micro-grid environment flow battery system and a control method thereof, and belongs to the technical field of micro-grid energy storage. The system comprises a photovoltaic power generation unit, a light storage inverter, a DC confluence unit, a flow battery, an AC confluence unit, a BMS control system and an electric load. The power part of the flow battery adopts a design of connecting multiple electric pile modules in parallel, the electric pile modules can be freely switched, the electric pile modules can be mutually standby, the redundancy is improved, the output voltage of the whole system is the same as the voltage of a single electric pile module, the phenomenon that part of the electric pile modules in the system cannot operate after faults occur is solved, and the robustness of the system is enhanced; when the power of the electricity load changes, the number of the electric piles in operation can be flexibly allocated according to the real-time value of the load power, the electric piles can be automatically put in and put out according to the actual power, the electricity demand of the load is responded in real time, the overall energy consumption is minimized, and resources are saved to the maximum extent.

Description

Technical Field

[0001] This invention belongs to the field of microgrid technology, specifically relating to a control method for a flow battery system in a microgrid environment. Background Technology

[0002] With the rapid development of the energy storage industry, long-term energy storage technology based on the all-vanadium redox flow battery (AVL) technology route is gaining increasing popularity. In microgrid applications, the commonly used solution is photovoltaic modules + photovoltaic-energy storage inverter + AVL. In existing AVL designs, most employ a series connection of multiple independent individual batteries. This means the AVL consists of a stack, electrolyte, and circulation pump, forming an independent system. This approach relies on each battery being in normal working order, and regardless of the power output of the solar energy or load, each battery must operate simultaneously, increasing losses and hindering coordinated operation. Due to individual battery differences, there are State of Charge (SOC) differences between batteries in the series system, requiring additional equalization circuits. Furthermore, the SOC difference between batteries must be within acceptable limits; otherwise, the "weakest link" effect becomes more pronounced, limiting the overall performance of the AVL. Additionally, if one battery in the series fails, the entire system must be shut down for repair, with no backup available, negatively impacting overall system stability. Summary of the Invention

[0003] To address the aforementioned problems in existing technologies, this invention proposes a flow battery system and its control method for microgrid environments. In this system, the flow battery employs a multi-stack parallel design, ensuring safety and reliability. It automatically disconnects from faulty stacks, and the output voltage of the entire system is identical to that of a single stack module. This solves the problem of the system failing to operate when some stack modules malfunction, enhancing the system's robustness. Furthermore, it can flexibly allocate the number of operating stacks based on real-time detected load power, automatically engaging and disengaging according to actual power demand, responding to load power requirements in real time, minimizing overall energy consumption, and maximizing resource savings.

[0004] The technical solution of the present invention is as follows:

[0005] A microgrid environment flow battery system includes photovoltaic modules, a photovoltaic-storage inverter, an AC combiner unit, a DC combiner unit, and a flow battery;

[0006] The PV port of the photovoltaic module is connected to the PV port of the photovoltaic-storage inverter for photovoltaic power generation; the number of the photovoltaic module and the photovoltaic-storage inverter are the same and they correspond one-to-one.

[0007] All the AC ports of the photovoltaic-storage inverters are connected to the AC combiner unit to power the equipment load and the flow battery control system.

[0008] The DC ports of all photovoltaic-storage inverters are connected to the DC combiner unit to power the flow batteries;

[0009] The flow battery is provided in multiple groups, and the multiple groups of the flow battery are connected in parallel with the DC combiner unit;

[0010] Each flow battery group consists of several stacks connected in parallel. All stacks within the same flow battery share a single positive and negative electrolyte. By increasing or decreasing the number of stacks within the flow battery, a dynamic balance is maintained between the various flow batteries.

[0011] According to some embodiments of this application, a microgrid environment flow battery system is provided, wherein the flow battery is provided in two groups, which can serve as backups for each other. Each group of flow batteries consists of nine stacks connected in parallel, and each stack is provided with a corresponding circulation pump, which can be independently switched on and off.

[0012] According to some embodiments of this application, in a microgrid environment flow battery system, multiple sets of flow batteries have their DC ports connected to a DC bus, and the DC bus is connected in parallel with the DC combiner unit via a cable.

[0013] According to some embodiments of this application, in a microgrid environment flow battery system, the grid interfaces of all photovoltaic-storage inverters are connected to the grid when there is a large power grid.

[0014] According to some embodiments of this application, in a microgrid environment flow battery system, the number of photovoltaic modules is determined based on the following method:

[0015] The total power of all electrical loads on site is counted, the power consumption of the electrical loads in 1 hour is calculated, and the total power consumption required for three consecutive days without sunlight under extreme conditions is calculated based on the power consumption in 1 hour, and then the battery capacity is matched.

[0016] Based on the geographical location and the average annual sunshine duration and intensity of the area, the shortest annual sunshine duration is selected. The battery charging power is calculated as (8h load power consumption + battery capacity) / shortest sunshine duration. The number of photovoltaic modules is calculated as (total charging power - load power) / power of a single photovoltaic panel.

[0017] A control method for a microgrid-environmental flow battery system employs a flow battery control system and an energy management system. The flow battery control system is integrated within the flow battery, real-time monitoring parameters such as stack voltage, current, electrolyte flow rate, temperature, and SOC (state of charge). Based on voltage, current, and feedback flow rate, it adjusts the pump speed to control the electrolyte flow rate, maintaining optimal reaction efficiency. The energy management system, located in the energy management cabinet, primarily collects battery parameter status feedback from the flow battery control system, parameters and status of the photovoltaic-storage inverter, and makes overall control decisions. The control method includes:

[0018] S1: Upon initial system commissioning, the photovoltaic-storage inverter converts the DC power provided by the photovoltaic modules into AC power, supplying it to the load and battery control system; the energy management system issues a start-up command, controlling each battery to start any stack and its corresponding circulation pump; the flow battery control system updates the battery's SOC data, forming a set of... The data is arranged in ascending order of the SOC value of each battery. For the total number of flow batteries, the energy management system will divide by the lowest SOC (i.e., Other fuel cells besides the one in question are out of service.

[0019] S2: Obtain the total photovoltaic charging power of all photovoltaic modules and schedule the operation of the stacks according to the first stack scheduling strategy. This involves comparing the total photovoltaic charging power with the total charging power of the currently deployed stacks. When the total photovoltaic charging power exceeds the upper limit of the current deployed stack's total charging power, the energy management system controls the battery to be deployed to more stacks; conversely, when the total photovoltaic charging power is significantly lower than the upper limit of the current deployed stack's total charging power, the energy management system controls the battery to be removed from some stacks. Specifically:

[0020] Let the battery that continues to operate in step S1 be the first operating battery, and its total number of battery stacks be... Each stack has a rated charging power or rated discharging power of [number] units. (Unit: kW), the current total photovoltaic charging power is (Unit: kW), the current number of fuel cell stacks in operation is: , ;

[0021] To avoid frequent actions around the threshold, a hysteresis control is implemented, where the thresholds for engagement and disengagement are different. This involves setting two threshold coefficients: the engagement threshold coefficient and the disengagement threshold coefficient. and exit threshold coefficient ,and ;

[0022] When the input conditions are met: and At that time, the currently operating battery is put into a battery stack. Increase by 1; after a switching interval S (unit: s), repeatedly determine whether the current total photovoltaic charging power and the current total charging power of the put-in stack meet the put-in conditions;

[0023] When the exit conditions are met: and At that time, the currently operating battery deploys one stack. Reduce by 1; after a switching interval S (unit: s), repeatedly check whether the current total photovoltaic charging power and the current total charging power of the fuel cell stack meet the exit conditions.

[0024] S3: As the SOC of the first operating battery increases during charging, the SOC difference between this battery and the other non-operating batteries gradually increases. The SOC value of the first operating battery is then compared with... Comparing the two, if the absolute value of the difference is greater than 20, then the rotation is initiated. Charge the corresponding battery; the battery rotation steps are as follows: First start The corresponding battery stack and its corresponding circulation pump are then stopped, and the first operating battery stack and its corresponding circulation pump are then put into operation. Each battery stack and its corresponding circulation pump are used in a cycle until all stacks of the first operating battery have ceased operation, completing the switchover; then... The corresponding battery, namely the second operating battery, is put into or taken out of the stack according to the first stack scheduling strategy in step S2, and the number of stacks is matched and switched.

[0025] The SOC value of the second running battery and Compare and complete the process described above. After charging and matching the corresponding battery, and then charging and matching the remaining batteries in order of increasing SOC value from step S1, respectively, calculate... The SOC values ​​of each battery are used to form a new set of data arranged from smallest to largest. Then according to arrive The batteries are charged and the stack is matched sequentially in sequence. This process is repeated until the SOC value of all batteries is greater than 95%, at which point the total charging power of the photovoltaic inverter is limited to 5kW.

[0026] S4: When the total power of photovoltaic charging is insufficient to maintain the load, the photovoltaic inverter automatically switches the charging batteries to a discharging state to supplement the lack of power, and switches to a discharge control strategy, as follows:

[0027] Will Sorting the SOC values ​​of the individual batteries from smallest to largest First of all The corresponding number The running battery begins discharging; the power of all current loads is acquired, and the battery stacks are scheduled according to the second battery stack scheduling strategy. This involves comparing the load power with the total discharge power of the currently running batteries. When the load power exceeds the upper limit of the total discharge power of the currently deployed battery stacks, the energy management system controls the deployment of more battery stacks; when the load power is lower than the upper limit of the total discharge power of the currently deployed battery stacks, the energy management system controls the removal of some battery stacks. Specifically:

[0028] When the input conditions are met: , This indicates the load power; currently, the operating battery is connected to one battery stack. Increase by 1; after a switching interval S (unit: s), repeatedly check whether the current load power and the total discharge power of the currently engaged stack meet the engagement conditions;

[0029] When the conditions for throwing are met: Currently, the operating battery deploys one stack. Reduce by 1; after a switching interval S (unit: s), repeatedly check whether the current load power and the total discharge power of the currently engaged stack meet the exit conditions.

[0030] S5: With the first During battery discharge, the SOC decreases, the first The SOC value of the running battery and The difference gradually increases, and when the absolute value of the SOC difference between the two is greater than 30, then it switches to The corresponding number Run the battery to discharge; the battery rotation steps are as follows: first start the first Running a battery stack and its corresponding circulation pump, then stopping the first one. A battery stack and its corresponding circulation pump are running, and then the second... A battery stack and its corresponding circulation pump operate in a cycle until the [number]th [time / phase / etc.]. All battery stacks in operation have been deactivated, and the switchover is complete; then, for the... The operating battery is put into or taken out of the stack according to the second stack scheduling strategy in step S4, and the number of stacks is matched and switched.

[0031] The first The SOC value of the running battery and Compare and complete the process described above. The corresponding number Battery discharge and stack matching, according to from arrive After discharging and matching the remaining batteries in sequence, calculate... The SOC values ​​of each battery are used to form a new set of data arranged from smallest to largest. Then according to arrive Discharge all batteries in sequence, repeating this process until the SOC value of all batteries is below 10%, then cut off the load power supply, leaving only the system to consume its own power until the next charge.

[0032] The beneficial effects of this invention are as follows: This invention provides a flow battery system for microgrid environments. The flow battery adopts a multi-stack parallel design, which is safe and reliable, automatically disconnects from faulty stacks, and the output voltage of the entire system is the same as the voltage of a single stack module. This solves the problem of the system being unable to operate after the failure of some modules within the system, enhancing the system's robustness. The system voltage being the same as the voltage of a single stack means that low-rated photovoltaic-storage inverters can be used, making it easier to couple and match with commonly used low-voltage systems (such as DC buses). The control system monitors the load power in real time and flexibly allocates the number of operating stacks according to the load power, automatically putting them into operation based on the actual power demand, responding to the load's power demand in real time, minimizing overall energy consumption, maximizing resource savings, and using non-operating stacks as backups. If one stack in the system fails (e.g., internal short circuit, severe leakage), in the parallel configuration, it will be "clamped" to a low voltage by other healthy stacks, thus automatically shutting down the system. The entire system will not completely shut down and can still be replaced by other normal modules. It enables self-sufficiency in electricity in various microgrid environments, such as oil fields in the desert and domestic electricity consumption on isolated islands. The surplus electricity supports grid-connected electricity sales, ensuring sufficient energy while reducing electricity costs, increasing electricity sales revenue, and improving power supply reliability. In a microgrid, it can serve as both a primary and backup power source. In areas without a main grid, it can support regional power supply. In areas with a main grid, it can support off-grid operation of the microgrid in the event of a main grid failure. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the microgrid environment energy storage system in the embodiment.

[0034] Figure 2 This is a control flowchart of the microgrid environment energy storage system in the embodiment. Detailed Implementation

[0035] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way. Unless otherwise specified, the experimental methods used in the embodiments are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0036] like Figure 1 As shown, this embodiment of the invention provides a microgrid environment flow battery system, including photovoltaic modules, a photovoltaic-storage inverter, an AC bus, a DC bus, and a flow battery;

[0037] The PV port of the photovoltaic module is connected to the PV port of the photovoltaic-storage inverter for photovoltaic power generation; the number of the photovoltaic module and the photovoltaic-storage inverter are the same and they correspond one-to-one.

[0038] All the AC ports of the photovoltaic-storage inverters are connected to the AC bus to power the equipment load and the flow battery control system.

[0039] All photovoltaic-storage inverters have their DC ports connected to the DC bus to power the flow batteries.

[0040] All photovoltaic and energy storage inverters' grid interfaces are connected to the power grid when a large power grid is available.

[0041] The flow battery is provided in two groups, and the DC ports of the two groups of flow batteries are connected to the DC bus. The DC bus and the DC busbar are connected in parallel via a cable.

[0042] Each flow battery consists of nine stacks connected in parallel, with each stack having its own circulation pump that can be switched on and off independently. All stacks within the same flow battery share the same positive and negative electrolyte. By increasing or decreasing the number of stacks within the flow battery, a dynamic balance is maintained between the various flow batteries.

[0043] like Figure 2 As shown, the control method for the above-mentioned microgrid environment flow battery system includes the following steps:

[0044] S1: When the system is first put into operation, the photovoltaic inverter converts the DC power provided by the photovoltaic modules into AC power, which is then supplied to the load and the battery control system. The energy management system issues a start command to control the start of any one of the two battery stacks and the corresponding circulation pump. The flow battery control system updates the SOC values ​​of the two batteries to 5% and 15% respectively, and the energy management system shuts down the stack with an SOC value of 15%.

[0045] S2: Assume the battery continuing to operate in step S1 is the first operating battery, with a total of 9 battery stacks, each stack having a rated charging power of 10 kW, a switching interval S set to 30 seconds, and an input threshold coefficient. It is 0.9.

[0046] The first operating battery meets the conditions for commissioning when it currently has one stack and a total photovoltaic charging power of 15 kW. One photovoltaic stack is put into operation; after a 30-second interval, when the total photovoltaic charging power reaches 25 kW, the operation conditions are met. That is, another photovoltaic stack is added; after a 30-second interval, when the total photovoltaic charging power becomes 35 kW, the conditions for commissioning are met. That is, another photovoltaic stack is put into operation; after a 30-second interval, when the total photovoltaic charging power becomes 46 kW, the operation conditions are met. That is, another photovoltaic stack is added; after a 30-second interval, when the total photovoltaic charging power becomes 55 kW, the conditions for commissioning are met. That is, another photovoltaic stack is put into operation; after a 30-second interval, when the total photovoltaic charging power becomes 64 kW, the operation conditions are met. That is, another fuel cell stack is added; after a 30-second interval, when the total photovoltaic charging power becomes 60 kW, There was no action at this time.

[0047] At this point, the SOC of the first operating battery is calculated to be 20%, while the SOC of the non-operating battery is 15%, which does not meet the battery switching conditions. Therefore, charging of the first operating battery continues. The total photovoltaic charging power remains at 60 kW. After a period of time, the total photovoltaic charging power changes from 60 kW to 52 kW. Let's define a threshold coefficient for exiting the battery switch. The value is 0.8, and the current number of fuel cell stacks in operation is 7, which meets the commissioning conditions. That is, by deploying one fuel cell stack, the number of operating fuel cell stacks becomes 6; after a 30-second interval, the total photovoltaic charging power becomes 50 kW. There was no action at this time.

[0048] The SOC of the first operating battery is calculated to be 35.01%, and the SOC of the non-operating battery is 15%, which meets the battery switching conditions. The switching is then performed to switch to another battery, namely the second operating battery, for charging. The second operating battery is then put into or removed from the battery stack according to the same stack scheduling strategy, and the number of battery stacks is matched and switched.

[0049] Then, calculate the SOC value of each battery separately, and charge and match the two batteries in order of increasing SOC value. Repeat this process until the SOC value of both batteries is greater than 95%, at which point the total charging power of the photovoltaic inverter is limited to 5kW.

[0050] S3: When the total photovoltaic charging power is 0, which is insufficient to maintain the load, the photovoltaic inverter automatically switches the charging battery to a discharging state to supplement the lack of power, and switches to a discharge control strategy, as follows:

[0051] The SOC values ​​of the two batteries are calculated to be 95% and 98%, respectively. First, the battery with an SOC of 98% is discharged. The current number of operating battery stacks for this battery is 2, and the load power is 15kW. When the load power increases to 25kW, the conditions for activation are met. This means that another fuel cell stack is put into operation; after a 30-second interval, the current status is checked again, and if there is no change, no action is taken; after 1 hour, the load power changes to 18kW, meeting the commissioning conditions. One battery stack is decommissioned; after a 30-second interval, it is determined that the current state has not changed; the SOC value of the battery at this time is calculated to be 62%, which meets the battery switching condition, so it is switched to another battery for discharge; then, the other battery is put into or dropped into the battery stack according to the same battery stack scheduling strategy, and the number of battery stacks is matched and switched.

[0052] Calculate the SOC value of each battery separately, and then discharge the two batteries in descending order of SOC value. Repeat this process until the SOC value of both batteries is below 10%. Then disconnect the load power supply and only retain the system's own power consumption until the next charging.

[0053] Although the above embodiments have described the technical solutions of the present invention in detail, they are only some preferred embodiments and not all embodiments of the present invention. Other embodiments obtained through non-creative effort based on these embodiments without departing from the spirit and principles of the present invention, as well as any modifications, equivalent substitutions, or improvements thereof, are all within the protection scope of the claims of the present invention.

Claims

1. A microgrid-environmental flow battery system, characterized in that, This includes photovoltaic modules, photovoltaic-energy storage inverters, AC combiner units, DC combiner units, and flow batteries; The photovoltaic-storage inverter is connected to the photovoltaic module, the AC combiner unit, and the DC combiner unit, respectively. The AC combiner unit is connected to the load and the flow battery control system; The flow battery is provided in multiple groups, and the multiple groups of the flow battery are connected in parallel with the DC combiner unit; Each flow battery group consists of several stacks connected in parallel. All stacks within the same flow battery share a single positive and negative electrolyte. By increasing or decreasing the number of stacks within the flow battery, a dynamic balance is maintained between the various flow batteries.

2. The microgrid environment flow battery system according to claim 1, characterized in that, The flow battery is configured in two groups, each group consisting of nine stacks connected in parallel. Each stack is equipped with a corresponding circulation pump, which can be independently switched on and off.

3. The microgrid environment flow battery system according to claim 1, characterized in that, Multiple sets of the flow batteries have their DC ports connected to a DC bus, and the DC bus is connected in parallel with the DC combiner unit via a cable.

4. The microgrid environment flow battery system according to claim 1, characterized in that, The number of photovoltaic modules and photovoltaic-storage inverters is the same; the grid interfaces of all photovoltaic-storage inverters are connected to the grid when there is a large power grid.

5. A microgrid environment flow battery system according to claim 1, characterized in that, The number of photovoltaic modules is obtained based on the following method: The total power of all electrical loads on site is counted, the power consumption of the electrical loads in 1 hour is calculated, and the total power consumption required for three consecutive days without sunlight under extreme conditions is calculated based on the power consumption in 1 hour, and then the battery capacity is matched. Based on the geographical location and the average annual sunshine duration and intensity of the area, the shortest annual sunshine duration is selected. The battery charging power is calculated as (8h load power consumption + battery capacity) / shortest sunshine duration. The number of photovoltaic modules is calculated as (total charging power - load power) / power of a single photovoltaic panel.

6. A control method for a microgrid-environmental flow battery system as described in any one of claims 1 to 5, characterized in that, Control is achieved using a flow battery control system and an energy management system, and the control method includes: S1: Upon initial system commissioning, the photovoltaic-storage inverter converts the DC power provided by the photovoltaic modules into AC power, supplying it to the load and battery control system; the energy management system issues a start-up command, controlling each battery to start any stack and its corresponding circulation pump; the flow battery control system updates the battery's SOC data, forming a set of... The data is arranged in ascending order of the SOC value of each battery. The total number of flow batteries, the energy management system will Fuel cells other than the corresponding fuel cell stacks are shut down; S2: Obtain the total photovoltaic charging power of all photovoltaic modules and schedule them according to the first stack scheduling strategy. The corresponding battery, namely the stack in the first operating battery, operates by comparing the total photovoltaic charging power with the total charging power of the currently invested battery. When the total photovoltaic charging power exceeds the upper limit of the total charging power of the stack in the currently invested battery, the energy management system controls the battery to invest more stacks; when the total photovoltaic charging power is lower than the upper limit of the total charging power of the stack in the currently invested battery, the energy management system controls the battery to withdraw some stacks. S3: Combine the SOC value of the first running battery with... Comparing the two, if the absolute value of the difference is greater than 20, then the rotation is initiated. Charge the corresponding battery; once the switch is complete, then... The corresponding battery, namely the second operating battery, is put into or taken out of the stack according to the first stack scheduling strategy in step S2, and the number of stacks is matched and switched. The SOC value of the second running battery and Compare, complete After charging and matching the corresponding battery, and then charging and matching the remaining batteries in order of increasing SOC value from step S1, respectively, calculate... The SOC value of each battery is determined, and then all batteries are charged and matched in order of increasing SOC value. This process is repeated until the SOC value of all batteries is greater than 95%, at which point the total charging power of the photovoltaic inverter is limited to 5kW. S4: When the total power of photovoltaic charging is insufficient to maintain the load, the photovoltaic inverter automatically switches the charging batteries to a discharging state to supplement the lack of power, and simultaneously switches to a discharge control strategy: Sorting the SOC values ​​of the individual batteries from smallest to largest First of all The corresponding number The battery begins discharging; the power of all current loads is acquired, and the second stack scheduling strategy is used to schedule the first stack. The operation of the battery stack involves comparing the load power with the total discharge power of the currently operating battery. When the load power exceeds the upper limit of the total discharge power of the currently deployed battery stack, the energy management system controls the battery to deploy more stacks; when the load power is lower than the upper limit of the total discharge power of the currently deployed battery stack, the energy management system controls the battery to remove some stacks. S5: The first The SOC value of the running battery and The comparison is performed, and when the absolute value of the difference in SOC between the two is greater than 30, then the system rotates to the next system. The corresponding number Run the battery to discharge; then, for the first The operating battery is put into or taken out of the stack according to the second stack scheduling strategy in step S4, and the number of stacks is matched and switched. The first The SOC value of the running battery and Compare and complete The corresponding number Battery discharge and stack matching, according to from arrive After discharging and matching the remaining batteries in sequence, calculate... The SOC value of each battery is determined, and then all batteries are discharged sequentially in descending order of SOC value. This process is repeated until the SOC value of all batteries is below 10%. At this point, the load power supply is cut off, and only the system itself consumes power until the next charging.

7. The control method for a microgrid environment flow battery system according to claim 6, characterized in that, The specific scheduling strategy for the first fuel cell stack is as follows: Assume the total number of battery stacks is Each stack has a rated charging power or rated discharging power of [number] units. Unit: kW; Current total photovoltaic charging power is Unit: kW; Number of fuel cell stacks currently in operation: , ; To avoid frequent actions around the threshold, a hysteresis control is implemented, where the thresholds for engagement and disengagement are different. This involves setting two threshold coefficients: the engagement threshold coefficient and the disengagement threshold coefficient. and exit threshold coefficient ,and ; When the input conditions are met: and At that time, the currently operating battery is put into a battery stack. Add 1; after the switching interval S, repeatedly check whether the current total photovoltaic charging power and the current total charging power of the battery stack meet the charging conditions; When the exit conditions are met: and At that time, the currently operating battery deploys one stack. Reduce by 1; after the switching interval S, repeatedly check whether the current total photovoltaic charging power and the current total charging power of the fuel cell stack meet the exit conditions.

8. The control method for a microgrid environment flow battery system according to claim 7, characterized in that, The second stack scheduling strategy is as follows: When the input conditions are met: , This indicates the load power; currently, the operating battery is connected to one battery stack. Add 1; after the switching interval S, repeatedly check whether the current load power and the total discharge power of the currently engaged stack meet the engagement conditions; When the conditions for throwing are met: Currently, the operating battery deploys one stack. Reduce by 1; after the switching interval S, repeatedly check whether the current load power and the total discharge power of the currently engaged stack meet the exit conditions.

9. The control method for a microgrid environment flow battery system according to claim 6, characterized in that, In step S3, the battery is switched to The steps for the corresponding battery are as follows: First, start the engine. The corresponding battery stack and its corresponding circulation pump are then stopped, and the first operating battery stack and its corresponding circulation pump are then put into operation. A corresponding battery stack and its corresponding circulation pump are used, and this process is repeated until all battery stacks of the first operating battery have exited operation, and the switching is complete.

10. The control method for a microgrid environment flow battery system according to claim 6, characterized in that, In step S5, the battery is switched to the first... The steps to run the battery are as follows: First, start the... Running a battery stack and its corresponding circulation pump, then stopping the first one. A battery stack and its corresponding circulation pump are running, and then the second... A battery stack and its corresponding circulation pump operate in a cycle until the [number]th [time / phase / etc.]. All battery stacks that were in operation have been deactivated, and the switchover is complete.

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