Networking type photovoltaic energy storage collaborative control method and system based on low-voltage alternating coupling

Abstract

This invention discloses a method and system for coordinated control of grid-connected photovoltaic (PV) and energy storage based on low-voltage AC coupling. The system includes at least one grid-connected PV inverter, with its DC side connected to a PV array and its AC side connected to a low-voltage AC bus; at least one grid-connected energy storage converter, with its DC side connected to an energy storage battery and its AC side connected to the low-voltage AC bus; an AC coupling transformer, with its low-voltage side connected to the low-voltage AC bus and its high-voltage side connected to a medium-voltage distribution network or load; and a central coordinating controller, which collects first parameters from the low-voltage AC bus and second parameters from the energy storage battery in real time, and issues corresponding control commands based on the target control strategy determined by the first and second parameters. This invention achieves deep synergy and complementary advantages between grid-connected PV and energy storage through AC coupling and central coordinating control, improving system robustness and adaptability while reducing energy storage capacity requirements and costs.

Description

Technical Field

[0001] This invention relates to the fields of new energy power generation and smart grid technology, and in particular to a method, system and storage medium for coordinated control of grid-type photovoltaic energy storage based on low-voltage AC coupling. Background Technology

[0002] With the high proportion of renewable energy sources, such as photovoltaics and wind power, being integrated into the power grid, the power system's electronic characteristics are becoming increasingly prominent. Traditional grid-forming inverters rely on grid voltage and frequency as synchronization signals, and their "following" characteristic makes the system lack proactive support capabilities during grid disturbances. Furthermore, when the penetration rate of renewable energy is extremely high, system inertia decreases, voltage / frequency stability deteriorates, and in severe cases, may trigger cascading failures. However, grid-forming converters can autonomously establish and maintain AC bus voltage and frequency through internal control algorithms, simulating the inertia of synchronous generators and the primary frequency and voltage regulation characteristics, providing the necessary voltage and frequency support to the grid. Therefore, grid-forming technology is key to solving these problems.

[0003] In related technologies, the application of grid-based technology is mainly concentrated in energy storage systems. However, relying solely on grid-based energy storage requires large-capacity storage batteries, resulting in high investment costs. Furthermore, the energy source is singular; during peak solar power generation periods, if the storage is already fully charged, the grid-based energy storage still needs to consume its own energy to maintain the mains, failing to prioritize the use of readily available renewable energy generation. Alternatively, attempts have been made to convert solar inverters to grid-based operation, but the intermittent and fluctuating nature of solar power generation makes standalone grid-based systems unreliable, failing to operate during rapid changes in sunlight or at night. Therefore, how to deeply integrate and synergize grid-based solar power and grid-based energy storage to reduce dependence on storage capacity while providing more stable, economical, and intelligent grid-based capabilities is an urgent problem to be solved. Summary of the Invention

[0004] The present invention proposes a collaborative control method, system and storage medium for grid-type photovoltaic energy storage based on low-voltage AC coupling, in order to solve one of the technical problems of high cost and insufficient reliability of grid-type photovoltaic energy storage in related technologies.

[0005] To achieve the above objectives, this invention proposes a grid-type photovoltaic energy storage collaborative control system based on low-voltage AC coupling, comprising:

[0006] At least one grid-type photovoltaic inverter, wherein the DC side of the grid-type photovoltaic inverter is connected to the photovoltaic array and the AC side is connected to the low-voltage AC bus; At least one grid-type energy storage converter, wherein the DC side of the grid-type energy storage converter is connected to the energy storage battery, and the AC side is connected to the low-voltage AC bus; An AC coupling transformer, wherein the low-voltage side of the AC coupling transformer is connected to the low-voltage AC bus, and the high-voltage side is connected to the medium-voltage distribution network or the load; The central coordinating controller is connected to the grid-type photovoltaic inverter and the grid-type energy storage converter through a communication network. The central coordinating controller collects the first parameter of the low-voltage AC bus and the second parameter of the energy storage battery in real time, and determines the target control strategy based on the first parameter and the second parameter through a preset coordinating control strategy. Based on the target control strategy, the central coordinating controller issues corresponding control commands to the grid-type photovoltaic inverter and the grid-type energy storage converter.

[0007] The grid-connected photovoltaic energy storage coordinated control method based on low-voltage AC coupling in this invention embodiment may also have the following additional technical features: In one embodiment of the present invention, the first parameter includes photovoltaic power generation and the second parameter includes state of charge; the step of determining the target control strategy based on the first parameter and the second parameter through a preset cooperative control strategy includes: When the photovoltaic power generation is greater than the first threshold and the state of charge is greater than the second threshold, the determined target control strategy is to set the grid-type photovoltaic inverter as the main grid-type unit and the grid-type energy storage converter as the slave grid-type unit. When the photovoltaic power generation is less than the third threshold or the state of charge is less than the fourth threshold, the determined target control strategy is to switch the grid-type energy storage converter to the main grid unit and the grid-type photovoltaic inverter to the slave grid unit or power-limited operation.

[0008] In one embodiment of the present invention, the method further includes: maintaining the original operating mode when the photovoltaic power generation is between the third threshold and the first threshold.

[0009] In one embodiment of the present invention, the method further includes: determining the virtual inertia constant of the grid-type photovoltaic inverter based on a virtual inertia adaptive algorithm of available photovoltaic power, wherein when the available photovoltaic power is large, the corresponding virtual inertia constant is increased; when the available photovoltaic power decreases, the virtual inertia constant is automatically decreased.

[0010] In one embodiment of the present invention, it further includes: The adjusted virtual synchronous generator parameters are determined based on the real-time state of charge. The adjusted virtual synchronous generator parameters are substituted into the control loop to monitor changes in grid parameters in real time and make dynamic corrections. When the state of charge returns to the normal range and the power grid operates stably, the virtual synchronous generator parameters are reset to their initial values.

[0011] In one embodiment of the present invention, the step of dynamically adjusting the virtual synchronous generator parameters according to the real-time state of charge and grid demand includes: If the real-time state of charge is in the high state of charge range, then increase the virtual inertia, simultaneously increase the damping coefficient, increase the frequency regulation coefficient, and keep the voltage support coefficient unchanged. If the real-time state of charge is in the low state of charge range, then the voltage support coefficient is increased, the virtual inertia is decreased to the minimum value, the frequency adjustment coefficient is decreased, and the damping coefficient is decreased to the minimum value.

[0012] In one embodiment of the present invention, the central coordination controller is further configured to: when a fault exit of the current main network unit is detected, immediately force a switch to another unit as the main network unit and issue an alarm message.

[0013] To achieve the above objectives, another aspect of the present invention proposes a method for coordinated control of grid-connected photovoltaic energy storage based on low-voltage AC coupling, comprising: Real-time acquisition of the first parameter of the low-voltage AC bus and the second parameter of the energy storage battery; The target control strategy is determined based on the first parameter and the second parameter through a preset collaborative control strategy. Based on the target control strategy, corresponding control commands are issued to the grid-type photovoltaic inverter and the grid-type energy storage converter.

[0014] Another object of the present invention is to provide an electronic device comprising: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the aforementioned method.

[0015] Another object of the present invention is to provide a computer storage medium, wherein the computer storage medium stores computer-executable instructions; the computer-executable instructions, when executed by a processor, cause the computer to perform the aforementioned method.

[0016] This invention discloses a method, system, and storage medium for coordinated control of grid-type photovoltaic energy storage based on low-voltage AC coupling. The system comprises at least one grid-type photovoltaic inverter, with its DC side connected to a photovoltaic array and its AC side connected to a low-voltage AC bus; at least one grid-type energy storage converter, with its DC side connected to an energy storage battery and its AC side connected to the low-voltage AC bus; an AC coupling transformer, with its low-voltage side connected to the low-voltage AC bus and its high-voltage side connected to a medium-voltage distribution network or load; and a central coordination controller, connected to both the grid-type photovoltaic inverter and the grid-type energy storage converter via a communication network. The central coordination controller collects first parameters from the low-voltage AC bus and second parameters from the energy storage battery in real time, and determines a target control strategy based on the first and second parameters using a preset coordinated control strategy. Based on the target control strategy, the central coordination controller issues corresponding control commands to the grid-type photovoltaic inverter and the grid-type energy storage converter. This invention achieves deep synergy and complementary advantages between grid-connected photovoltaics and energy storage through AC coupling and central collaborative control, which improves system robustness and adaptability while reducing energy storage capacity requirements and costs.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the structure of a grid-type photovoltaic energy storage collaborative control system based on low-voltage AC coupling according to an embodiment of the present invention; Figure 2 This is a schematic flowchart of a grid-type photovoltaic energy storage collaborative control method based on low-voltage AC coupling according to an embodiment of the present invention. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] The following describes, with reference to the accompanying drawings, a method and system for coordinated control of grid-type photovoltaic energy storage based on low-voltage AC coupling, according to embodiments of the present invention.

[0022] Figure 1 This is a schematic diagram of the structure of a grid-type photovoltaic energy storage collaborative control system based on low-voltage AC coupling according to an embodiment of the present invention, as shown below. Figure 1 As shown, the system may include: At least one grid-type photovoltaic inverter, with the DC side of the grid-type photovoltaic inverter connected to the photovoltaic array and the AC side connected to the low-voltage AC bus; At least one grid-type energy storage converter, with the DC side of the grid-type energy storage converter connected to the energy storage battery and the AC side connected to the low-voltage AC bus; An AC coupling transformer is a transformer whose low-voltage side is connected to a low-voltage AC bus, and whose high-voltage side is connected to a medium-voltage distribution network or load. The central coordinating controller is connected to the grid-type photovoltaic inverter and the grid-type energy storage converter through a communication network. The central coordinating controller collects the first parameter of the low-voltage AC bus and the second parameter of the energy storage battery in real time. Based on the first and second parameters, it determines the target control strategy through a preset coordinating control strategy and issues corresponding control commands to the grid-type photovoltaic inverter and the grid-type energy storage converter based on the target control strategy.

[0023] Further, in one embodiment of the present invention, the first parameter may include photovoltaic power generation and the second parameter may include state of charge (SOC). In one embodiment of the present invention, the method for determining a target control strategy based on the first and second parameters using a preset collaborative control strategy may include: when the photovoltaic power generation is greater than a first threshold and the SOC is greater than a second threshold, the determined target control strategy is to set the grid-connected photovoltaic inverter as the master grid-connected unit and the grid-connected energy storage converter as the slave grid-connected unit; when the photovoltaic power generation is less than a third threshold or the SOC is less than a fourth threshold, the determined target control strategy is to switch the grid-connected energy storage converter to the master grid-connected unit and the grid-connected photovoltaic inverter to the slave grid-connected unit or operate with power limitation. Furthermore, in one embodiment of the present invention, the first threshold may be 60% of the rated power, the second threshold may be 50% of the rated SOC, the third threshold may be 30% of the rated power, and the fourth threshold may be 20% of the rated SOC.

[0024] In one embodiment of the present invention, the system further includes: when the photovoltaic power generation is between the third threshold and the first threshold, maintaining the original operating mode to form a hysteresis loop and prevent frequent switching.

[0025] In one embodiment of the present invention, if the grid-connected photovoltaic inverter is the main grid-connected unit, the virtual inertia constant of the grid-connected photovoltaic inverter can be determined based on the virtual inertia adaptive algorithm of available photovoltaic power. Specifically, when the available photovoltaic power is large, the corresponding virtual inertia constant is increased; when the available photovoltaic power decreases, the virtual inertia constant is automatically decreased. In another embodiment of the present invention, the virtual inertia adaptive algorithm of available photovoltaic power can be performed through linear mapping. That is, the real-time available photovoltaic power is used as input, and a virtual inertia constant that continuously changes with power is output through a preset mapping rule.

[0026] For example, in one embodiment of the present invention, if the available photovoltaic power is less than or equal to the power threshold, the virtual inertia constant is automatically reduced to the minimum virtual inertia constant; if the available photovoltaic power is greater than or equal to (1 - power threshold), the virtual inertia constant is automatically increased to the maximum virtual inertia constant; if the power threshold is less than the available photovoltaic power and less than (1 - power threshold), adjustments are made using a mapping formula, where the mapping formula is J_adaptive = J_min + (J_max - J_min) × (P_norm - P_thr) / (1 - 2 × P_thr), where J_adaptive is the virtual inertia constant, J_min is the minimum virtual inertia constant, J_max is the maximum virtual inertia constant, P_norm is the available photovoltaic power, and P_thr is the power threshold.

[0027] In one embodiment of the present invention, if the grid-type energy storage converter is the main grid-connecting unit, the adjusted virtual synchronous generator parameters can be determined according to the real-time state of charge; the adjusted virtual synchronous generator parameters are substituted into the control loop to monitor the changes in grid parameters in real time and make dynamic corrections; when the state of charge returns to the normal range and the grid operation is stable, the virtual synchronous generator parameters are reset to the initial value.

[0028] In one embodiment of the present invention, the method for dynamically adjusting the parameters of a virtual synchronous generator according to the real-time state of charge and grid demand may include: if the real-time state of charge is in the high state of charge range, increasing the virtual inertia, simultaneously increasing the damping coefficient, increasing the frequency regulation coefficient, and maintaining the voltage support coefficient unchanged; if the real-time state of charge is in the low state of charge range, increasing the voltage support coefficient, decreasing the virtual inertia to the minimum value, decreasing the frequency regulation coefficient, and decreasing the damping coefficient to the minimum value.

[0029] In one embodiment of the present invention, if the real-time state of charge (SOC) ≥ SOC_high, the real-time state of charge is determined to be in the high state of charge range; if SOC_low < SOC < SOC_high, the real-time state of charge is determined to be in the normal SOC range; if SOC ≤ SOC_low, the real-time state of charge is determined to be in the low state of charge range. In one embodiment of the present invention, SOC_low can be 20% of the rated state of charge, and SOC_high can be 80% of the rated state of charge.

[0030] In one embodiment of the present invention, if the real-time state of charge is in the high state of charge range, the virtual inertia is increased, the damping coefficient is increased simultaneously, the frequency regulation coefficient is adjusted upwards, and the voltage support coefficient remains unchanged. Specifically, in one embodiment of the present invention, the virtual inertia J can be adjusted from the initial value J0 to the maximum value J_max, and the adjustment range is positively correlated with the SOC. The virtual inertia J can be determined by a preset formula, which is J=J0+(J_max-J0)×(SOC-SOC_high) / (100%-SOC_high), where J0 is the initial value of the virtual inertia; the damping coefficient D is simultaneously adjusted upwards to D_max (e.g., 15~20 N·m·s / rad), which, together with the increase of J, suppresses frequency oscillation and avoids system response lag due to excessive inertia; the voltage support coefficient Kv remains at the initial value Kv0 to ensure basic voltage support capability and is not adjusted preferentially; the frequency regulation coefficient Kf is adjusted upwards to Kf_max (e.g., 10~12) to improve frequency regulation sensitivity, quickly respond to grid frequency deviation, and strengthen the frequency support effect.

[0031] In one embodiment of the present invention, if the real-time state of charge is in the low state of charge range, the voltage support coefficient is increased, the virtual inertia is decreased to a minimum value, the frequency regulation coefficient is decreased, and the damping coefficient is decreased to a minimum value. Specifically, in one embodiment of the present invention, the voltage support coefficient Kv is increased from the initial value Kv0 to Kv_max (e.g., 8~10) to improve voltage regulation sensitivity, quickly respond to grid voltage deviations, and prioritize maintaining grid connection point voltage stability; the virtual inertia J can be decreased to a minimum value J_min (e.g., 0.5~1s) to reduce energy consumption caused by inertial response and avoid excessive discharge of stored energy; the frequency regulation coefficient Kf is decreased to Kf_min (e.g., 4~6) to reduce the frequency regulation depth; and the damping coefficient D is decreased to D_min (e.g., 5~8 N·m·s / rad), which, together with the decrease in Kf, reduces energy fluctuations during frequency regulation.

[0032] Furthermore, in one embodiment of the present invention, after obtaining the adjusted virtual synchronous generator parameters through the above steps, namely the virtual inertia J, damping coefficient D, voltage support coefficient Kv, and frequency regulation coefficient Kf, the adjusted virtual synchronous generator parameters are substituted into the VSG swing equation and voltage control loop to monitor the changes in grid frequency and voltage in real time and determine the adjustment effect. Specifically, in one embodiment of the present invention, if the frequency still drops when at a high SOC or the voltage still deviates significantly when at a low SOC, the corresponding VSG parameters are finely adjusted (the magnitude does not exceed 10%) until the grid parameters tend to stabilize.

[0033] Furthermore, in one embodiment of the present invention, when the state of charge returns to the normal range and the power grid operates stably, the parameters of the virtual synchronous generator can be reset to their initial values.

[0034] Furthermore, in one embodiment of the present invention, the aforementioned central coordination controller can also be used to: immediately force a switch to another unit as the main network unit when a fault exit is detected in the current main network unit, and issue an alarm message.

[0035] In one embodiment of the present invention, an AC coupling transformer can be used to boost the low-voltage side power to a medium-voltage level to meet the requirements of grid connection or long-distance transmission; and when the system draws power from a medium-voltage distribution network, the transformer can step down the medium voltage to a low voltage to provide power for local loads or energy storage batteries.

[0036] In one embodiment of the present invention, through the above-mentioned coordinated control, the system can be mainly responsible for grid construction by photovoltaics when there is sufficient photovoltaic power during the day, while energy storage is in a "standby" and "maintenance" state; at night or on cloudy or rainy days, energy storage can seamlessly take over to ensure continuous power supply to local loads in off-grid or weak grid conditions, so that the entire system presents itself to the outside world as a highly reliable virtual power plant with friendly grid connection characteristics.

[0037] This invention relates to a low-voltage AC-coupled grid-type photovoltaic energy storage collaborative control system, comprising at least one grid-type photovoltaic inverter, with its DC side connected to a photovoltaic array and its AC side connected to a low-voltage AC bus; at least one grid-type energy storage converter, with its DC side connected to an energy storage battery and its AC side connected to the low-voltage AC bus; an AC coupling transformer, with its low-voltage side connected to the low-voltage AC bus and its high-voltage side connected to a medium-voltage distribution network or load; and a central collaborative controller, connected to both the grid-type photovoltaic inverter and the grid-type energy storage converter via a communication network. The central collaborative controller collects first parameters of the low-voltage AC bus and second parameters of the energy storage battery in real time, and determines a target control strategy based on the first and second parameters using a preset collaborative control strategy. Based on the target control strategy, the central collaborative controller issues corresponding control commands to the grid-type photovoltaic inverter and the grid-type energy storage converter. This invention achieves deep synergy and complementary advantages between grid-connected photovoltaics and energy storage through AC coupling and central collaborative control, which improves system robustness and adaptability while reducing energy storage capacity requirements and costs.

[0038] To achieve the above embodiments, such as Figure 2 As shown in the figure, this embodiment also provides a flowchart of a grid-type photovoltaic energy storage collaborative control method based on low-voltage AC coupling. The method may include the following steps: Step 201: Real-time acquisition of the first parameters of the low-voltage AC bus and the second parameters of the energy storage battery; Step 202: Determine the target control strategy based on the first parameter and the second parameter using a preset collaborative control strategy; Step 203: Based on the target control strategy, issue corresponding control commands to the grid-type photovoltaic inverter and the grid-type energy storage converter.

[0039] In one embodiment of the present invention, the relevant descriptions of steps 201 to 203 can be found in the detailed descriptions in the above embodiments, and will not be repeated in this embodiment.

[0040] According to an embodiment of the present invention, a grid-type photovoltaic energy storage collaborative control method based on low-voltage AC coupling acquires first parameters of the low-voltage AC bus and second parameters of the energy storage battery in real time; determines a target control strategy based on the first and second parameters through a preset collaborative control strategy; and issues corresponding control commands to the grid-type photovoltaic inverter and the grid-type energy storage converter based on the target control strategy. This invention achieves deep synergy and complementary advantages between grid-type photovoltaic and energy storage through AC coupling and central collaborative control, improving system robustness and adaptability while reducing energy storage capacity requirements and costs.

[0041] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A grid-type photovoltaic energy storage collaborative control system based on low-voltage AC coupling, characterized in that, include: At least one grid-type photovoltaic inverter, wherein the DC side of the grid-type photovoltaic inverter is connected to the photovoltaic array and the AC side is connected to the low-voltage AC bus; At least one grid-type energy storage converter, wherein the DC side of the grid-type energy storage converter is connected to the energy storage battery, and the AC side is connected to the low-voltage AC bus; An AC coupling transformer, wherein the low-voltage side of the AC coupling transformer is connected to the low-voltage AC bus, and the high-voltage side is connected to the medium-voltage distribution network or the load; The central coordinating controller is connected to the grid-type photovoltaic inverter and the grid-type energy storage converter through a communication network. The central coordinating controller collects the first parameter of the low-voltage AC bus and the second parameter of the energy storage battery in real time, and determines the target control strategy based on the first parameter and the second parameter through a preset coordinating control strategy. Based on the target control strategy, the central coordinating controller issues corresponding control commands to the grid-type photovoltaic inverter and the grid-type energy storage converter.

2. The system according to claim 1, characterized in that, The first parameter includes photovoltaic power generation and the second parameter includes state of charge; the step of determining the target control strategy based on the first parameter and the second parameter through a preset collaborative control strategy includes: When the photovoltaic power generation is greater than the first threshold and the state of charge is greater than the second threshold, the determined target control strategy is to set the grid-type photovoltaic inverter as the main grid-type unit and the grid-type energy storage converter as the slave grid-type unit. When the photovoltaic power generation is less than the third threshold or the state of charge is less than the fourth threshold, the determined target control strategy is to switch the grid-type energy storage converter to the main grid unit and the grid-type photovoltaic inverter to the slave grid unit or power-limited operation.

3. The system according to claim 2, characterized in that, Also includes: When the photovoltaic power generation is between the third threshold and the first threshold, the original operating mode is maintained.

4. The system according to claim 3, characterized in that, Also includes: The virtual inertia constant of the grid-type photovoltaic inverter is determined based on the virtual inertia adaptive algorithm of available photovoltaic power. When the available photovoltaic power is large, the corresponding virtual inertia constant is increased; when the available photovoltaic power decreases, the virtual inertia constant is automatically decreased.

5. The system according to claim 3, characterized in that, Also includes: The adjusted virtual synchronous generator parameters are determined based on the real-time state of charge. The adjusted virtual synchronous generator parameters are substituted into the control loop to monitor changes in grid parameters in real time and make dynamic corrections. When the state of charge returns to the normal range and the power grid operates stably, the virtual synchronous generator parameters are reset to their initial values.

6. The system according to claim 5, characterized in that, The process of determining the adjusted virtual synchronous generator parameters based on the real-time state of charge includes: If the real-time state of charge is in the high state of charge range, then increase the virtual inertia, simultaneously increase the damping coefficient, increase the frequency regulation coefficient, and keep the voltage support coefficient unchanged. If the real-time state of charge is in the low state of charge range, then the voltage support coefficient is increased, the virtual inertia is decreased to the minimum value, the frequency adjustment coefficient is decreased, and the damping coefficient is decreased to the minimum value.

7. The system according to claim 1, characterized in that, The central coordination controller is also used to: immediately force a switch to another unit as the main network unit when the current main network unit is detected to have failed and exited, and issue an alarm message.

8. A method for coordinated control of grid-type photovoltaic energy storage based on low-voltage AC coupling, characterized in that, include: Real-time acquisition of the first parameter of the low-voltage AC bus and the second parameter of the energy storage battery; The target control strategy is determined based on the first parameter and the second parameter through a preset collaborative control strategy. Based on the target control strategy, corresponding control commands are issued to the grid-type photovoltaic inverter and the grid-type energy storage converter.

9. An electronic device, comprising: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method of claim 8.

10. A computer storage medium, wherein, The computer storage medium stores computer-executable instructions; when executed by a processor, the computer-executable instructions can implement the method as described in claim 8.

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