Energy storage system control method and energy storage system

Abstract

The present application provides an energy storage system control method and an energy storage system, wherein the method includes: obtaining the control mode of the energy storage system and the state of charge of each battery cluster unit; determining the total power balance formula of the energy storage system according to the control mode and the preset virtual load; and controlling each battery cluster unit to charge and discharge according to the total power balance formula and the state of charge of each battery cluster unit. The present application can dynamically adjust the charging and discharging process of each battery cluster unit under the premise of stable operation of the energy storage system. At the same time, the charging and discharging control of each battery cluster unit can be realized without calculating the difference in the state of charge between each battery cluster unit, thereby avoiding the complicated calculation of the difference in the state of charge between each battery cluster unit, reducing the consumption of computing resources and time, and improving the response speed of the energy storage system.

Description

Technical Field

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

[0002] When multiple single-phase or three-phase power conversion systems (PCS) in an energy storage system are operated in parallel off-grid, the charge states of the battery clusters corresponding to the multiple PCSs may be different. The difference may be caused by the different initial states of the battery clusters, or slight differences in the charge and discharge circuits, or other reasons. The difference in the charge state of the battery clusters corresponding to the multiple PCSs will result in a smaller available capacity of the energy storage system and low battery cluster utilization during the life cycle. The charge state balance problem when the PCSs are operated in parallel is a pain point in the industry.

[0003] The state of charge control method in the prior art usually needs to calculate the difference between the states of charge of battery clusters corresponding to multiple PCSs, so as to achieve state of charge balance.

[0004] However, this implementation requires a lot of calculations, and the stability of the energy storage system is difficult to guarantee during the state of charge balancing process. Summary of the invention

[0005] The purpose of the present application is to provide an energy storage system control method and an energy storage system in view of the above-mentioned deficiencies in the prior art, so as to solve the problem of low stability when controlling the charge state of each battery cluster of the energy storage system in the prior art.

[0006] To achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

[0007] In a first aspect, an embodiment of the present application provides an energy storage system control method, which is applied to an energy storage system, wherein the energy storage system at least includes: a plurality of battery cluster devices connected in parallel, each of the battery cluster devices includes a battery cluster unit and an energy storage converter, and the method includes:

[0008] Acquiring a control mode of the energy storage system and a state of charge of each of the battery cluster units;

[0009] Determine the total power balance formula of the energy storage system according to the control mode and the preset virtual load, wherein the virtual load is used to simulate the load in the energy storage system, and the total power balance formula is used to characterize the conditions that the actual power of each battery cluster unit and the virtual power of the virtual load should satisfy when the power of each battery cluster unit is balanced;

[0010] According to the total power balance formula and the charge state of each battery cluster unit, each battery cluster unit is controlled to be charged and discharged.

[0011] Optionally, the preset virtual load includes: a virtual load corresponding to each of the battery cluster units, and a resistance value of the virtual load corresponding to each of the battery cluster units is positively correlated with a state of charge of each of the battery cluster units.

[0012] Optionally, controlling each of the battery cluster units to charge and discharge according to the total power balance formula and the charge state of each of the battery cluster units includes:

[0013] Determining the resistance value of the virtual load corresponding to each of the battery cluster units according to the charge state of each of the battery cluster units;

[0014] Determine the actual power corresponding to each of the battery cluster units according to the total power balance formula and the resistance value of the virtual load corresponding to each of the battery cluster units;

[0015] According to the actual power corresponding to each battery cluster unit, each battery cluster unit is controlled to be charged and discharged.

[0016] Optionally, determining the resistance value of the virtual load corresponding to each of the battery cluster units according to the charge state of each of the battery cluster units includes:

[0017] Determine the maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each of the battery cluster units;

[0018] The resistance value of the virtual load corresponding to each of the battery cluster units is determined according to the maximum resistance value of the virtual load corresponding to each of the battery cluster units, the minimum resistance value of the virtual load and the charge state of each of the battery cluster units.

[0019] Optionally, the determining of the maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each of the battery cluster units includes:

[0020] Determine the total power of the current battery cluster units;

[0021] According to the total power, a maximum resistance value of a virtual load and a minimum resistance value of a virtual load corresponding to the current battery cluster unit are determined.

[0022] Optionally, the determining of the maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each of the battery cluster units includes:

[0023] Obtaining system parameters of the energy storage system;

[0024] According to the system parameters of the energy storage system, the maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each of the battery cluster units are determined.

[0025] Optionally, determining the actual power corresponding to each of the battery cluster units according to the total power balance formula and the resistance value of the virtual load corresponding to each of the battery cluster units includes:

[0026] Determining the virtual power corresponding to each of the battery cluster units according to the resistance value of the virtual load corresponding to each of the battery cluster units;

[0027] The virtual power value of each battery cluster unit is input into the total power balance formula of the energy storage system to determine the actual power corresponding to each battery cluster unit.

[0028] Optionally, controlling each of the battery cluster units to charge and discharge according to the total power balance formula and the charge state of each of the battery cluster units includes:

[0029] Determining the virtual power corresponding to each of the battery cluster units according to the charge state of each of the battery cluster units;

[0030] Determine the actual power corresponding to each of the battery cluster units according to the total power balance formula and the virtual power corresponding to each of the battery cluster units;

[0031] According to the actual power corresponding to each battery cluster unit, each battery cluster unit is controlled to be charged and discharged.

[0032] Optionally, determining the virtual power corresponding to each of the battery cluster units according to the state of charge of each of the battery cluster units includes:

[0033] Determine a virtual load maximum power value and a virtual load minimum power value corresponding to each of the battery cluster units;

[0034] The virtual power corresponding to each of the battery cluster units is determined according to the charge state of each of the battery cluster units, the maximum power value of the virtual load, and the minimum power value of the virtual load.

[0035] Optionally, the determining the maximum power value of the virtual load and the minimum power value of the virtual load corresponding to each of the battery cluster units includes:

[0036] Acquiring the actual power of each of the battery cluster units;

[0037] According to the actual power of each battery cluster unit, a virtual load maximum power value and a virtual load minimum power value corresponding to each battery cluster unit are determined.

[0038] Optionally, determining a total power balance formula of the energy storage system according to the control mode and a preset virtual load includes:

[0039] Constructing an equivalent circuit model of the energy storage system according to the control mode and the preset virtual load;

[0040] According to the equivalent circuit model, a total power balance formula of the energy storage system is determined.

[0041] Optionally, constructing an equivalent circuit model of the energy storage system according to the control mode and a preset virtual load includes:

[0042] determining an initial closed-loop control structure of the energy storage system;

[0043] Adding a preset virtual load to the initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system;

[0044] An equivalent circuit model of the energy storage system is generated according to the target closed-loop control structure.

[0045] Optionally, the initial closed-loop control structure is a first initial closed-loop control structure;

[0046] The step of adding a preset virtual load to the initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system includes:

[0047] A preset virtual load is added to both ends of the output voltage of the inverter in the first initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system.

[0048] Optionally, the initial closed-loop control structure is a second initial closed-loop control structure;

[0049] The step of adding a preset virtual load to the initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system includes:

[0050] A preset virtual load is added across the voltage in the second initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system.

[0051] In a second aspect, another embodiment of the present application provides an energy storage system, the energy storage system comprising: a plurality of battery cluster devices connected in parallel and a control device, the control device being used to execute the energy storage system control method described in the first aspect.

[0052] The beneficial effects of the present application are as follows: by acquiring the control mode of the energy storage system and the state of charge of each battery cluster unit, and determining the total power balance formula of the energy storage system according to the control mode and the preset virtual load, it is possible to control the charging and discharging of each battery cluster unit according to the total power balance formula and the state of charge of each battery cluster unit, so that the charging and discharging process of each battery cluster unit can be dynamically adjusted under the premise of stable operation of the energy storage system, and at the same time, the charging and discharging control of each battery cluster unit can be realized without calculating the difference in the state of charge between each battery cluster unit, thereby avoiding the complicated calculation of the difference in the state of charge between each battery cluster unit, reducing the consumption of computing resources and time, and improving the response speed of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0054] Figure 1 A schematic diagram of the structure of an energy storage system provided in an embodiment of the present application;

[0055] Figure 2 A schematic diagram of a flow chart of an energy storage system control method provided in an embodiment of the present application;

[0056] Figure 3 A schematic diagram of a flow chart for controlling each battery cluster unit to charge and discharge in the energy storage system control method provided in an embodiment of the present application;

[0057] Figure 4 A schematic diagram of a flow chart for determining the resistance value of a virtual load corresponding to each battery cluster unit in the energy storage system control method provided in an embodiment of the present application;

[0058] Figure 5 A schematic diagram of a flow chart for determining the maximum resistance value of a virtual load and the minimum resistance value of a virtual load corresponding to each battery cluster unit in the energy storage system control method provided in an embodiment of the present application;

[0059] Figure 6 Another schematic diagram of a flow chart for determining the maximum resistance value of a virtual load and the minimum resistance value of a virtual load corresponding to each battery cluster unit in the energy storage system control method provided in an embodiment of the present application;

[0060] Figure 7 Another schematic diagram of a flow chart of controlling each battery cluster unit to charge and discharge in the energy storage system control method provided in an embodiment of the present application;

[0061] Figure 8 A schematic diagram of a process for determining the virtual power corresponding to each battery cluster unit in the energy storage system control method provided in an embodiment of the present application;

[0062] Fig. 9 A schematic diagram of a flow chart for determining a virtual load maximum power value and a virtual load minimum power value corresponding to each battery cluster unit in the energy storage system control method provided in an embodiment of the present application;

[0063] Fig.10 A schematic diagram of a flow chart for determining a total power balance formula of an energy storage system in an energy storage system control method provided in an embodiment of the present application;

[0064] Fig.11 A schematic diagram of a flow chart for constructing an equivalent circuit model of an energy storage system in the energy storage system control method provided in an embodiment of the present application;

[0065] Fig.12 A schematic diagram of a first initial closed-loop control structure in an energy storage system control method provided in an embodiment of the present application;

[0066] Fig.13 A first schematic diagram of a target closed-loop control structure in an energy storage system control method provided in an embodiment of the present application;

[0067] Fig.14 A structural schematic diagram of an equivalent circuit model of an energy storage system in an energy storage system control method provided in an embodiment of the present application;

[0068] Fig.15 Another structural schematic diagram of an equivalent circuit model of an energy storage system in the energy storage system control method provided in an embodiment of the present application;

[0069] Fig.16 A second schematic diagram of a target closed-loop control structure in the energy storage system control method provided in an embodiment of the present application;

[0070] Fig.17 A third schematic diagram of a target closed-loop control structure in the energy storage system control method provided in an embodiment of the present application;

[0071] Fig.18 Another structural schematic diagram of an equivalent circuit model of an energy storage system in the energy storage system control method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0072] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of explanation and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn in real proportion. The flowchart used in this application shows the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowchart can be implemented out of sequence, and the steps without logical context can be reversed in order or implemented simultaneously. In addition, those skilled in the art can add one or more other operations to the flowchart under the guidance of the content of the present application, or remove one or more operations from the flowchart.

[0073] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0074] It should be noted that the term "comprising" will be used in the embodiments of the present application to indicate the existence of the features declared thereafter, but does not exclude the addition of other features.

[0075] The state of charge control method in the prior art usually needs to calculate the difference between the state of charge of the battery clusters corresponding to multiple PCSs, so as to achieve the state of charge balance. However, this implementation method requires a lot of calculations, and during the state of charge balance process, the stability of the energy storage system is difficult to ensure.

[0076] Based on the above problems, an embodiment of the present application proposes a method for controlling an energy storage system. The method obtains the control mode of the energy storage system and the state of charge of each battery cluster unit, and determines the total power balance formula of the energy storage system according to the control mode and a preset virtual load. Thus, the charging and discharging of each battery cluster unit can be controlled according to the total power balance formula and the state of charge of each battery cluster unit. The stability of the energy storage system can be ensured when each battery cluster unit is charged and discharged. At the same time, the charging and discharging control of the energy storage system can be realized without calculating the difference in the state of charge between each battery cluster unit, thereby avoiding a complicated state of charge (SOC) calculation process, reducing the consumption of computing resources and time, and improving the response speed of the energy storage system.

[0077] First, an energy storage system involved in the energy storage system control method provided in an embodiment of the present application is exemplarily described.

[0078] Figure 1 A schematic diagram of a structure of an energy storage system provided in an embodiment of the present application, referring to Figure 1 As shown, the energy storage system provided by the embodiment of the present application includes at least: a plurality of battery cluster devices connected in parallel, each battery cluster device includes a battery cluster unit and an energy storage converter. After the battery cluster unit is connected in series with the energy storage converter, it is connected to the bus to charge and discharge to the grid, or discharge to the load.

[0079] Optionally, an energy storage converter is used to realize energy conversion and bidirectional flow between the battery cluster unit and the power grid or load.

[0080] Optionally, the energy storage system also includes a battery management system (BMS) to monitor the operating status of each battery in each battery cluster unit to ensure safe and reliable operation of the energy storage system.

[0081] Optionally, the energy storage system also includes an energy management system (EMS) for interacting with the PCS and the BMS to execute the energy storage system control method provided in the embodiment of the present application to control the charging and discharging of each battery cluster unit.

[0082] It can be understood that before charging and discharging each battery cluster unit, the steps of the energy storage system control method provided in the embodiment of the present application can be executed to control each battery cluster unit to charge and discharge in a balanced manner. It is also possible that during the charging and discharging process of each battery cluster unit, the steps of the energy storage system control method provided in the embodiment of the present application can be executed to adjust the charging and discharging process of each battery cluster unit within an adjustment cycle, and after the current adjustment cycle ends, each battery cluster unit is controlled to charge and discharge in a balanced manner.

[0083] The energy storage system control method provided in the embodiments of the present application is described in detail below in combination with multiple embodiments.

[0084] Figure 2 A schematic diagram of a flow chart of the energy storage system control method provided in the embodiment of the present application, referring to Figure 2 As shown, the method is applied to a control device in the above energy storage system, such as the above EMS, and the method includes:

[0085] S201 : Acquire a control mode of an energy storage system and a state of charge of each battery cluster unit.

[0086] It can be understood that when controlling the charging and discharging of each battery cluster unit in the energy storage system, the control mode of the energy storage system and the charge state of each battery cluster unit are first obtained, so that based on the control mode and the charge state of each battery cluster unit, each battery cluster unit can be controlled to charge and discharge in the most stable manner to ensure the stability and reliability of the energy storage system.

[0087] Among them, the control mode of the energy storage system refers to the strategy used by the energy storage converter to control the energy storage system to work. Specifically, the control mode of the energy storage system includes the control method of the energy storage converter based on the current loop, such as: master-slave control method, average current control method, distributed logic control method with communication lines, droop control method and virtual synchronous machine control method.

[0088] The state of charge (SOC) refers to the ratio of the electric energy stored in each battery cluster unit at the current moment to the electric energy that can be stored when it is fully charged, reflecting the remaining capacity and available time of the battery cluster.

[0089] S202. Determine a total power balance formula of the energy storage system according to the control mode and the preset virtual load.

[0090] Optionally, after determining the control mode of the energy storage system, a virtual load of a preset size is added to the energy storage system based on the control mode of the energy storage system, and an equivalent circuit model of the energy storage system is determined according to the energy storage system after the virtual load is added, so as to obtain a total power balance formula of the energy storage system by calculating the virtual power corresponding to the virtual load in the equivalent circuit model and the actual power corresponding to each battery cluster unit.

[0091] Optionally, after determining the control mode of the energy storage system, a virtual load of a preset size is added to the energy storage system based on the control mode of the energy storage system, and the virtual power corresponding to the virtual load and the actual power corresponding to each battery cluster unit are input into a power balance equation pre-constructed based on the energy conservation principle of the energy storage system, so that the total power balance formula of the energy storage system can be obtained by solving the power balance equation.

[0092] Optionally, different virtual loads can be added to different locations of the energy storage system according to different control modes. For example, when the control mode of the energy storage system is the average current control mode, a virtual load connected in series or in parallel with each battery cluster unit can be added to each battery cluster unit in the energy storage system. When the control mode of the energy storage system is a distributed logic control mode with a communication line, a virtual load connected in series or in parallel with the load can be added to the energy storage system according to the charge state of each battery cluster unit in the energy storage system.

[0093] The virtual load is used to simulate the load in the energy storage system. The virtual load may include one load or multiple loads corresponding to each battery cluster unit. The total load power balance formula corresponding to each battery cluster unit is used to characterize the actual power of each battery cluster unit and the virtual power of the virtual load when the power of each battery cluster unit is balanced.

[0094] Specifically, power balance refers to a balance state achieved between the actual power output or input of each battery cluster unit and the virtual power output or input of the virtual load under the control mode of the energy storage system, which enables the energy storage system to operate stably.

[0095] S203 , controlling each battery cluster unit to charge and discharge according to the total power balance formula and the charge state of each battery cluster unit.

[0096] Optionally, after obtaining the total power balance formula, the size of the virtual load can be adjusted according to the charge state of each battery cluster unit, and the actual power of each battery cluster unit can be determined according to the charge state of each battery cluster unit, so that the actual power of each battery cluster unit can be adjusted according to the size of the virtual load, the actual power of each battery cluster unit and the total power balance formula, thereby controlling the charging and discharging of each battery cluster unit.

[0097] Optionally, after obtaining the total power balance formula, the actual power of each battery cluster unit can be determined according to the charge state of each battery cluster unit, and the virtual power of the virtual load can be adjusted according to the actual power of each battery cluster unit, thereby adjusting the actual power of each battery cluster unit based on the total power balance formula and the virtual power of the virtual load, thereby realizing the control of charging and discharging of each battery cluster unit.

[0098] Optionally, after obtaining the total power balance formula, the actual power of each battery cluster unit can be determined according to the charge state of each battery cluster unit, so as to adjust the actual power of each battery cluster unit according to the preset virtual load, the actual power of each battery cluster unit and the total power balance formula, so as to control the charging and discharging of each battery cluster unit.

[0099] Exemplarily, the resistance of the virtual load can be adjusted according to the state of charge of each battery cluster unit, and the actual power of each battery cluster unit can be determined according to the state of charge of each battery cluster unit. Therefore, according to the resistance of the virtual load, the actual power of each battery cluster unit and the total power balance formula, the actual power of each battery cluster unit can be adjusted, thereby controlling the charging and discharging of each battery cluster unit.

[0100] Exemplarily, the power size of the virtual load can be adjusted according to the charge state of each battery cluster unit, and the actual power of each battery cluster unit can be determined according to the charge state of each battery cluster unit. Therefore, according to the power size of the virtual load, the actual power of each battery cluster unit and the total power balance formula, the actual power of each battery cluster unit can be adjusted to control the charging and discharging of each battery cluster unit.

[0101] In this embodiment, by acquiring the control mode of the energy storage system and the state of charge of each battery cluster unit, and determining the total power balance formula of the energy storage system according to the control mode and the preset virtual load, it is possible to control the charging and discharging of each battery cluster unit according to the total power balance formula and the state of charge of each battery cluster unit, so that the charging and discharging process of each battery cluster unit can be dynamically adjusted under the premise of stable operation of the energy storage system. At the same time, the charging and discharging control of each battery cluster unit can be achieved without calculating the difference in the state of charge between each battery cluster unit, thereby avoiding the complicated calculation of the difference in the state of charge between each battery cluster unit, reducing the consumption of computing resources and time, and improving the response speed of the energy storage system.

[0102] In a possible implementation, the preset virtual load includes: a virtual load corresponding to each battery cluster unit, and a resistance value of the virtual load corresponding to each battery cluster unit is positively correlated with a state of charge of each battery cluster unit.

[0103] Optionally, when the control mode of the energy storage system is any one of a master-slave control mode, an average current control mode, a distributed logic control mode with a communication line, a droop control mode, and a virtual synchronous machine control mode, the preset virtual load includes the virtual load corresponding to each battery cluster unit.

[0104] Among them, when the control mode of the energy storage system is any one of the master-slave control mode, the average current control mode, the distributed logic control mode with a communication line, the droop control mode and the virtual synchronous machine control mode, the resistance value of the virtual load corresponding to each battery cluster unit is positively correlated with the charge state of each battery cluster unit, that is, the resistance value of the virtual load corresponding to each battery cluster unit can be adjusted according to the charge state of each battery cluster unit. When the charge state of each battery cluster unit increases, the resistance value of the virtual load corresponding to each battery cluster unit is increased, so that the actual power output or input of each battery cluster unit and the virtual power output or input of the virtual load can reach a balanced state of stable operation of the energy storage system more quickly.

[0105] Among them, when the control mode of the energy storage system is any one of the droop control mode and the virtual synchronous machine control mode, the virtual power of the virtual load corresponding to each battery cluster unit is negatively correlated with the charge state of each battery cluster unit, that is, the power size of the virtual load corresponding to each battery cluster unit can also be adjusted according to the charge state of each battery cluster unit. When the charge state of each battery cluster unit increases, the virtual power of the virtual load corresponding to each battery cluster unit is reduced, so that the actual power output or input of each battery cluster unit and the virtual power output or input of the virtual load can reach a balanced state of stable operation of the energy storage system more quickly.

[0106] That is to say, when controlling the charging and discharging of the energy storage system, different adjustment strategies can be adopted for the virtual load of the energy storage system according to the different control modes of the energy storage system, so that the actual power output or input of each battery cluster unit and the virtual power output or input of the virtual load can reach a balanced state for stable operation of the energy storage system more quickly.

[0107] Specifically, for the master-slave control method, the average current control method, and the distributed logic control method with a communication line, the resistance value of the virtual load corresponding to each battery cluster unit can be adjusted according to the charge state of each battery cluster unit. For the droop control method and the virtual synchronous machine control method, not only can the resistance value of the virtual load corresponding to each battery cluster unit be adjusted according to the charge state of each battery cluster unit, but the power of the virtual load corresponding to each battery cluster unit can also be adjusted according to the charge state of each battery cluster unit.

[0108] The following is an exemplary description of the process of adjusting the resistance of the virtual load corresponding to each battery cluster unit according to the charge state of each battery cluster unit, thereby controlling the charging and discharging of each battery cluster unit.

[0109] In a possible implementation, a process of controlling each battery cluster unit to charge and discharge according to the total power balance formula and the charge state of each battery cluster unit is exemplarily described. Figure 3 A schematic diagram of a flow chart of controlling each battery cluster unit to charge and discharge in the energy storage system control method provided in the embodiment of the present application, referring to Figure 3 As shown, the above S203 includes:

[0110] S301 : Determine the resistance value of the virtual load corresponding to each battery cluster unit according to the charge state of each battery cluster unit.

[0111] Optionally, the resistance value of the virtual load corresponding to each battery cluster unit may be obtained according to the state of charge of each battery cluster unit and a pre-stored mapping relationship between the state of charge and the resistance value of the virtual load.

[0112] Optionally, the resistance value of the virtual load corresponding to each battery cluster unit may be calculated according to the charge state of each battery cluster unit.

[0113] The resistance value of the virtual load corresponding to each battery cluster unit is used to indicate the size of the virtual load corresponding to each battery cluster unit when the virtual load includes the virtual load corresponding to each battery cluster unit.

[0114] S302 : Determine the actual power corresponding to each battery cluster unit according to the total power balance formula and the resistance value of the virtual load corresponding to each battery cluster unit.

[0115] Optionally, after the resistance value of the virtual load corresponding to each battery cluster unit is obtained, the actual power corresponding to each battery cluster unit may be calculated according to the total power balance formula and the resistance value of the virtual load corresponding to each battery cluster unit.

[0116] The actual power corresponding to each battery cluster unit is used to indicate the power actually output or actually consumed by each battery cluster unit in the current working state.

[0117] Exemplarily, the resistance value of the virtual load corresponding to each battery cluster unit may be input into the total power balance formula to calculate the actual power corresponding to each battery cluster unit.

[0118] S303 , controlling each battery cluster unit to charge and discharge according to the actual power corresponding to each battery cluster unit.

[0119] Optionally, after the actual power corresponding to each battery cluster unit is obtained, each battery cluster unit may be controlled to charge and discharge at a corresponding charge and discharge rate according to the actual power corresponding to each battery cluster unit.

[0120] Exemplarily, the actual power corresponding to each battery cluster unit is used as the charge and discharge power allocated to each battery cluster unit, and each battery cluster unit is controlled to perform charge and discharge.

[0121] The resistance value of the virtual load corresponding to each battery cluster unit is determined by the charge state of each battery cluster unit, and the actual power corresponding to each battery cluster unit is determined by the total power balance formula and the resistance value of the virtual load corresponding to each battery cluster unit. Thus, the actual power corresponding to each battery cluster unit is used to control the charging and discharging of each battery cluster unit. The charging and discharging process of each battery cluster unit in an energy storage system where an energy storage converter based on a current loop control method is located can be smoothly controlled, and at the same time, the stability of the energy storage system can be improved.

[0122] In one possible implementation, Figure 4 A schematic diagram of a flow chart for determining the resistance value of the virtual load corresponding to each battery cluster unit in the energy storage system control method provided in an embodiment of the present application, referring to Figure 4As shown, when the above S301 determines the resistance value of the virtual load corresponding to each battery cluster unit according to the charge state of each battery cluster unit, it can be performed according to the following steps, including:

[0123] S401 : Determine a maximum resistance value of a virtual load and a minimum resistance value of a virtual load corresponding to each battery cluster unit.

[0124] Optionally, the maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to the battery cluster unit may be determined first. The maximum resistance value of the virtual load is used to indicate the resistance value of the virtual load when the virtual load is close to a full load state, and the minimum resistance value of the virtual load is used to indicate the resistance value of the virtual load when the virtual load is close to an unloaded state. The maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each battery cluster unit may be the same or different.

[0125] For example, the maximum resistance of the virtual load can be determined according to the performance and attribute information of the energy storage system. And the minimum resistance of the dummy load , as the maximum resistance of the virtual load corresponding to each battery cluster unit And the minimum resistance of the dummy load .

[0126] S402 , determining the resistance value of the virtual load corresponding to each battery cluster unit according to the maximum resistance value and the minimum resistance value of the virtual load corresponding to each battery cluster unit and the charge state of each battery cluster unit.

[0127] Optionally, after obtaining the maximum resistance of the virtual load And the minimum resistance of the dummy load After that, the maximum resistance of the virtual load corresponding to each battery cluster unit can be , Minimum resistance of virtual load and the state of charge of each battery cluster unit , and calculate the resistance value of the virtual load corresponding to each battery cluster unit.

[0128] For example, the resistance value of the virtual load corresponding to each battery cluster unit can be calculated by referring to the following formula (1): :

[0129] (1)

[0130] in, is the state of charge of each battery cluster unit, is the minimum resistance of the virtual load of each battery cluster unit, is the maximum resistance of the virtual load of each battery cluster unit.

[0131] By determining the maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each battery cluster unit, and determining the resistance value of the virtual load corresponding to each battery cluster unit through the maximum resistance value of the virtual load, the minimum resistance value of the virtual load and the charge state of each battery cluster unit, it is possible to set a suitable virtual load resistance value for each battery cluster unit, thereby achieving balanced charging and discharging between each battery cluster unit, helping to avoid damage to certain battery cluster units due to excessive charging and discharging, while ensuring the performance and stability of the entire energy storage system.

[0132] In a possible implementation, taking any one of the battery cluster units as the current battery cluster unit as an example, the process of determining the maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each battery cluster unit is exemplarily described. Figure 5 A schematic diagram of a flow chart for determining the maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each battery cluster unit in the energy storage system control method provided in the embodiment of the present application, referring to Figure 5 As shown, the above S401 includes:

[0133] S501 : Determine the total power of the current battery cluster units.

[0134] Optionally, the total power Ptotal of the current battery cluster unit can be determined, wherein the total power Ptotal of the current battery cluster unit can be understood as the total power of the energy storage converter corresponding to the current battery cluster unit, which is charged and discharged at the previous moment before the current adjustment cycle. Exemplarily, it can be the sum of the virtual power of the virtual load corresponding to the current battery cluster unit and the actual power of the current battery cluster unit.

[0135] S502: Determine the maximum resistance value and the minimum resistance value of the virtual load corresponding to the current battery cluster unit according to the total power.

[0136] Optionally, after the total power Ptotal is obtained, the maximum resistance of the virtual load corresponding to each battery cluster unit can be calculated according to the total power Ptotal. And the minimum resistance of the dummy load .

[0137] For example, when The maximum resistance of the virtual load can be calculated by referring to the following formulas (2)-(3): And the minimum resistance of the dummy load :

[0138] (2)

[0139] (3)

[0140] in, . as well as All are positive integers.

[0141] For example, when When , the maximum resistance of the virtual load can be obtained by referring to the following formula (4): And the minimum resistance of the dummy load :

[0142] (4)

[0143] The maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each battery cluster unit are determined by the total power of each battery cluster unit, so that the maximum resistance value and the minimum resistance value of the virtual load can change with the state of the energy storage system, thereby achieving balanced charging and discharging between each battery cluster unit more quickly and avoiding large differences in actual power between each battery cluster unit.

[0144] In one possible implementation, Figure 6 Another flow chart of determining the maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each battery cluster unit in the energy storage system control method provided in the embodiment of the present application, referring to Figure 6 As shown, the above S401 determines the maximum resistance value and the minimum resistance value of the virtual load corresponding to each battery cluster unit, including:

[0145] S601. Obtain system parameters of the energy storage system.

[0146] Among them, the system parameters of the energy storage system may include battery discharge rate, energy conversion efficiency, cycle life, energy capacity, power capacity, depth of discharge (DOD), energy density and specific energy, etc.

[0147] S602 : Determine the maximum resistance value and the minimum resistance value of the virtual load corresponding to each battery cluster unit according to the system parameters of the energy storage system.

[0148] Optionally, the maximum virtual load resistance and the minimum virtual load resistance corresponding to each battery cluster unit may be obtained according to a pre-stored mapping relationship between system parameters of the energy storage system and the maximum virtual load resistance and the minimum virtual load resistance corresponding to each battery cluster unit.

[0149] In a possible implementation, the above S302 determines the actual power corresponding to each battery cluster unit according to the total power balance formula and the resistance value of the virtual load corresponding to each battery cluster unit, including:

[0150] The virtual power corresponding to each battery cluster unit is determined according to the resistance value of the virtual load corresponding to each battery cluster unit.

[0151] Optionally, the virtual power corresponding to each battery cluster unit can be calculated according to the resistance value of the virtual load corresponding to each battery cluster unit. .

[0152] The virtual power value of each battery cluster unit is input into the total power balance formula of the energy storage system to determine the actual power corresponding to each battery cluster unit.

[0153] Optionally, the virtual power corresponding to each battery cluster unit is obtained Input the total power balance formula of the energy storage system and calculate the actual power corresponding to each battery cluster unit.

[0154] The above is an exemplary description of the process of controlling the charging and discharging of each battery cluster unit by adjusting the resistance of the virtual load corresponding to each battery cluster unit through the charge state of each battery cluster unit. The following is an exemplary description of the process of controlling the charging and discharging of each battery cluster unit by adjusting the power of the virtual load corresponding to each battery cluster unit through the charge state of each battery cluster unit.

[0155] In one possible implementation, Figure 7 Another schematic diagram of a flow chart of controlling each battery cluster unit to charge and discharge in the energy storage system control method provided in the embodiment of the present application, referring to Figure 7 As shown, the above S203 controls each battery cluster unit to charge and discharge according to the total power balance formula and the charge state of each battery cluster unit, including:

[0156] S701 : Determine the virtual power corresponding to each battery cluster unit according to the charge state of each battery cluster unit.

[0157] Optionally, the virtual power corresponding to each battery cluster unit may be obtained according to a mapping relationship between the state of charge of each battery cluster unit and the state of charge of each battery cluster unit and the virtual power.

[0158] Optionally, the virtual power corresponding to each battery cluster unit may also be calculated according to the charge state of each battery cluster unit.

[0159] S702: Determine the actual power corresponding to each battery cluster unit according to the total power balance formula and the virtual power corresponding to each battery cluster unit.

[0160] Optionally, after the virtual power corresponding to each battery cluster unit is obtained, the actual power corresponding to each battery cluster unit may be calculated according to the total power balance formula and the virtual power corresponding to each battery cluster unit.

[0161] The actual power corresponding to each battery cluster unit is used to indicate the power actually output or actually consumed by each battery cluster unit in the current working state.

[0162] Exemplarily, the virtual power corresponding to each battery cluster unit may be input into a total power balance formula to calculate the actual power corresponding to each battery cluster unit.

[0163] S703 , controlling each battery cluster unit to charge and discharge according to the actual power corresponding to each battery cluster unit.

[0164] Optionally, after the actual power corresponding to each battery cluster unit is obtained, each battery cluster unit may be controlled to charge and discharge at a corresponding charge and discharge rate according to the actual power corresponding to each battery cluster unit.

[0165] Exemplarily, the actual power corresponding to each battery cluster unit is used as the charge and discharge power allocated to each battery cluster unit, and each battery cluster unit is controlled to perform charge and discharge.

[0166] The virtual power corresponding to each battery cluster unit is determined by the charge state of each battery cluster unit, and the actual power corresponding to each battery cluster unit is determined by the total power balance formula and the virtual power corresponding to each battery cluster unit. Therefore, the charging and discharging of each battery cluster unit is controlled according to the actual power corresponding to each battery cluster unit. The charging and discharging of each battery cluster unit can be directly controlled by the power of the virtual load, avoiding indirect adjustment of the power of the virtual load by the resistance value of the virtual load. The charging and discharging process of each battery cluster unit in the energy storage system where the energy storage converter of the droop control mode and the virtual synchronous machine control mode is located can be smoothly controlled.

[0167] In one possible implementation, Figure 8 A schematic diagram of a flow chart for determining the virtual power corresponding to each battery cluster unit in the energy storage system control method provided in an embodiment of the present application, referring to Figure 8 As shown, the above S701 determines the virtual power corresponding to each battery cluster unit according to the charge state of each battery cluster unit, including:

[0168] S801: Determine a virtual load maximum power value and a virtual load minimum power value corresponding to each battery cluster unit.

[0169] Optionally, the maximum power value of the virtual load corresponding to each battery cluster unit can be determined separately. And the minimum power value of the virtual load Among them, the maximum power value of the virtual load is Used to indicate the power value of the virtual load when the virtual load is close to full load state, the minimum power value of the virtual load It is used to indicate the power value of the virtual load when the virtual load is close to the no-load state. Among them, the maximum power value of the virtual load between each battery cluster unit and the minimum power value of the virtual load Can be the same or different.

[0170] S802 : Determine the virtual power corresponding to each battery cluster unit according to the state of charge of each battery cluster unit, the maximum power value of the virtual load, and the minimum power value of the virtual load.

[0171] Optionally, after obtaining the maximum power value of the virtual load corresponding to each battery cluster unit And the minimum power value of the virtual load After that, the maximum power value of the virtual load corresponding to each battery cluster unit can be And the minimum power value of the virtual load and the state of charge of each battery cluster , respectively calculate the virtual power corresponding to each battery cluster unit .

[0172] For example, the resistance value of the virtual load corresponding to each battery cluster unit can be calculated by referring to the following formula (5): :

[0173] (5)

[0174] in, is the state of charge of each battery cluster unit, is the minimum power value of the virtual load corresponding to each battery cluster unit, is the maximum power value of the virtual load corresponding to each battery cluster unit.

[0175] By determining the maximum power value of the virtual load and the minimum power value of the virtual load corresponding to each battery cluster unit, and determining the virtual power corresponding to each battery cluster unit through the charge state of each battery cluster unit, the maximum power value of the virtual load and the minimum power value of the virtual load, a suitable virtual load power value can be set for each battery cluster unit, so that when the virtual load is small, the virtual power of the virtual load is also small, and when the virtual load is large, the virtual power of the virtual load is also large, thereby achieving balanced charging and discharging between each battery cluster unit, helping to avoid damage to some battery cluster units due to excessive charging and discharging, and ensuring the performance and stability of the entire energy storage system.

[0176] In a possible implementation, taking any one of the battery cluster units as the current battery cluster unit as an example, the process of determining the maximum power value of the virtual load and the minimum power value of the virtual load corresponding to each battery cluster unit is exemplarily described. Fig. 9A schematic diagram of a flow chart for determining the maximum power value of the virtual load and the minimum power value of the virtual load corresponding to each battery cluster unit in the energy storage system control method provided in the embodiment of the present application, referring to Fig. 9 As shown, the above S801 includes:

[0177] S901: Acquire the actual power of each battery cluster unit.

[0178] Optionally, obtain the actual power of the current battery cluster unit , where the actual power of the current battery cluster unit is It can be understood as the power value of the current battery cluster unit when charging and discharging at the previous moment.

[0179] S902: Determine a virtual load maximum power value and a virtual load minimum power value corresponding to each battery cluster unit according to the actual power of each battery cluster unit.

[0180] Optionally, the actual power of the current battery cluster unit can be , calculate the maximum power value of the virtual load corresponding to each battery cluster unit And the minimum power value of the virtual load .

[0181] For example, the minimum power value of the virtual load can be calculated using the following formula (6): :

[0182] (6)

[0183] For example, the maximum power value of the virtual load can be calculated using the following formula (7): :

[0184] (7)

[0185] in, is the actual power of the current battery cluster unit, as well as is a pre-set impact factor. .

[0186] The above is an exemplary description of the process of controlling the charging and discharging of each battery cluster unit according to the total power balance formula and the charge state of each battery cluster unit. The following is an exemplary description of determining the total power balance formula of the energy storage system according to the control mode and the preset virtual load.

[0187] In one possible implementation, Fig.10 A schematic diagram of a flow chart for determining the total power balance formula of the energy storage system in the energy storage system control method provided in the embodiment of the present application, referring to Fig.10As shown, in the above S202, according to the control mode and the preset virtual load, the total power balance formula of the energy storage system is determined, including:

[0188] S1001. Construct an equivalent circuit model of the energy storage system according to the control mode and the preset virtual load.

[0189] Optionally, since multiple battery cluster devices are connected in parallel in the energy storage system, when determining the total power balance formula of the energy storage system, one battery cluster device in the energy storage system can be taken as an example, and a virtual load can be added to the position corresponding to the battery cluster device in the energy storage system, so that an equivalent circuit model corresponding to a battery cluster device in the energy storage system can be constructed based on the energy storage system after the virtual load is added.

[0190] Optionally, after obtaining an equivalent circuit model corresponding to a battery cluster device in the energy storage system, equivalent circuit models corresponding to multiple battery cluster devices may be connected in parallel to obtain an equivalent circuit model of the energy storage system.

[0191] S1002. Determine a total power balance formula for the energy storage system based on the equivalent circuit model.

[0192] Optionally, the equivalent circuit model may be mathematically expressed based on the operating objectives of the energy storage system during charging and discharging, thereby obtaining a total power balance formula for the energy storage system.

[0193] For example, the operation target of the energy storage system during charging and discharging may be to evenly distribute power among multiple battery cluster devices. The total power balance formula of the energy storage system may refer to the following formula (8):

[0194] (8)

[0195] in, is the virtual power of the virtual load corresponding to the Nth battery cluster device, is the actual power of the Nth battery cluster device, where N is a positive integer.

[0196] Through the control mode of the energy storage system and the preset virtual load, an equivalent circuit model of the energy storage system is constructed, and based on the equivalent circuit model, the total power balance formula of the energy storage system is determined. The actual power of each battery cluster unit and the conditions that the virtual power of the virtual load should meet when the power of each battery cluster unit is balanced are characterized, which helps to ensure balanced power distribution among the battery cluster units and prevent overcharging or over-discharging of some units, thereby improving the performance and stability of the entire energy storage system.

[0197] In one possible implementation, Fig.11A schematic diagram of a flow chart for constructing an equivalent circuit model of an energy storage system in the energy storage system control method provided in an embodiment of the present application, referring to Fig.11 As shown, the above S1001 constructs an equivalent circuit model of the energy storage system according to the control mode and the preset virtual load, including:

[0198] S1101. Determine an initial closed-loop control structure of an energy storage system.

[0199] Optionally, the initial closed-loop control structure of the energy storage system may be determined according to the control mode of the energy storage system, taking a battery cluster device in the energy storage system as an example.

[0200] The initial closed-loop control structure of the energy storage system can be understood as the basic strategy of the energy storage converter to control the energy storage system to work. For example, the initial closed-loop control structure can be a dual closed-loop control structure of voltage outer loop and current inner loop.

[0201] S1102: Add a preset virtual load to the initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system.

[0202] Optionally, according to different control modes of the energy storage system, a preset virtual load is added to the initial closed-loop control structure to obtain a target closed-loop control structure corresponding to the energy storage system.

[0203] S1103. Generate an equivalent circuit model of the energy storage system according to the target closed-loop control structure.

[0204] Optionally, after the target closed-loop control structure is obtained, an equivalent circuit model corresponding to a battery cluster device in the energy storage system may be generated based on the corresponding relationship between the target closed-loop control structure and the equivalent circuit model.

[0205] Optionally, after obtaining an equivalent circuit model corresponding to a battery cluster device in the energy storage system, equivalent circuit models corresponding to multiple battery cluster devices may be connected in parallel to obtain an equivalent circuit model of the energy storage system.

[0206] In a possible implementation, the initial closed-loop control structure is a first initial closed-loop control structure, and the above S1102 adds a preset virtual load to the initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system, including:

[0207] In the first initial closed-loop control structure, a preset virtual load is added to both ends of the output voltage of the inverter to obtain a target closed-loop control structure of the energy storage system.

[0208] For example, Fig.12 This is a schematic diagram of the first initial closed-loop control structure in the energy storage system control method provided in the embodiment of the present application, referring to Fig.12As shown, when the control mode of the energy storage system is any one of the master-slave control mode, the average current control mode, the distributed logic control mode with communication lines, the droop control mode and the virtual synchronous machine control mode, the first initial closed-loop control structure can be a dual closed-loop control structure using a voltage outer loop and a current inner loop, wherein u ref is the voltage loop given signal, PI is the proportional integral controller, Gcur(s) is the current closed loop, i Lref is the given signal of the current loop, i L is the inductor current, i o is the output current, s represents the response of the system to the time derivative of the input signal, C f is the capacitance value of the filter capacitor, v c is the output of the voltage controller.

[0209] For example, Fig.13 A first schematic diagram of a target closed-loop control structure in the energy storage system control method provided in an embodiment of the present application, referring to Fig.13 As shown, in Fig.12 On this basis, preset virtual loads are added at both ends of the output voltage of the inverter, that is, a signal is derived from the output capacitor voltage, and this voltage signal is divided by a virtual load Rv, and the virtual current signal of the virtual load Rv is subtracted from the given signal of the current loop. Since the speed of the current inner loop is very fast compared to the voltage outer loop, the closed-loop gain of the current loop can be made approximately equal to 1.

[0210] Among them, u ref is the voltage loop given signal, PI is the proportional integral controller, Gcur(s) is the current closed loop, I lref is the given signal of the current loop, i L is the actual output inductor current, s represents the system response to the time derivative of the input signal, C f is the capacitance value of the filter capacitor, v c is the output of the voltage controller, R v is the resistance of the virtual load. total By U ref Total power emitted, P virtual is the virtual power consumed by the virtual load Rv, P real It is the real power output by the energy storage converter. Taking the output direction as the positive direction, it can be determined that: .

[0211] For example, on this basis, by executing the above step S1103, an equivalent circuit model corresponding to a battery cluster device in the energy storage system can be obtained as follows: Fig.14 As shown, Fig.14A schematic diagram of an equivalent circuit model of an energy storage system in an energy storage system control method provided in an embodiment of the present application, wherein u ref is the voltage given signal, Z eq is the sum of the equivalent line impedance obtained by the control loop and the real line impedance, i LT for u ref The total current delivered, i v is the virtual current flowing through the virtual load Rv, i L is the actual output inductor current, i LT for i lref ,i o is the output current, C f is the filter capacitor, i c is the capacitor current, Z load is the real line impedance. total By u ref Total power emitted, P virtual is the virtual power consumed by the virtual load Rv, P real It is the energy storage converter that emits real power.

[0212] For example, taking two battery cluster devices connected in parallel as an example, the equivalent circuit model corresponding to the energy storage system can be obtained as follows: Fig.15 As shown, Fig.15 Another structural schematic diagram of an equivalent circuit model of an energy storage system in an energy storage system control method provided in an embodiment of the present application, wherein u ref1 is the voltage given signal of the first battery cluster device, u ref2 is the voltage given signal of the second battery cluster device, i LT1 for u ref1 The total current delivered, i LT2 for u ref2 The total current delivered, i v1 is the virtual current flowing through the virtual load Rv1, i v2 is the virtual current flowing through the virtual load Rv2, i L1、 i L2 is the actual output inductor current, C f is the filter capacitor, i c is the capacitor current, Z load is the real line impedance, Z eq It is the sum of the equivalent line impedance obtained by the control loop and the real line impedance. total1 is the total power generated by the first battery cluster device, P total2 is the total power generated by the second battery cluster device, P virtual1 is composed of a dummy load R v1 Virtual power consumed, P virtual2 is composed of a dummy load R v2Virtual power consumed, P real1 is the real power generated by the energy storage converter of the first battery cluster device, P real2 It is the energy storage converter of the second battery cluster device that generates real power.

[0213] In a possible implementation, the initial closed-loop control structure is a second initial closed-loop control structure, and the above S1102 adds a preset virtual load to the initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system, including:

[0214] A preset virtual load is added across the voltage in the second initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system.

[0215] For example, Fig.16 This is a second schematic diagram of the target closed-loop control structure in the energy storage system control method provided in the embodiment of the present application. When the control mode of the energy storage system is the droop control mode, taking a battery cluster device in the energy storage system as an example, the equivalent voltage U ref Add preset virtual loads at both ends of the target closed-loop control structure as follows Fig.16 shown.

[0216] Among them, Uref is the voltage given signal, P is the active power, Q is the reactive power, Pref is the active rated value, Qref is the reactive rated value, P virtual is the virtual power consumed by the virtual load Rv, P real is the real power output by the energy storage converter, K p is the active power droop coefficient, K Q is the reactive droop coefficient, E* is the internal potential amplitude, Ui is the voltage parameter, ω* is the angular frequency, s represents the response of the system to the time derivative of the input signal, and θ is the impedance angle.

[0217] For example, Fig.17 This is a third schematic diagram of the target closed-loop control structure in the energy storage system control method provided in the embodiment of the present application. When the control mode of the energy storage system is the virtual synchronous machine control mode, taking a battery cluster device in the energy storage system as an example, the equivalent voltage U ref Add preset virtual loads at both ends of the target closed-loop control structure as follows Fig.17 shown.

[0218] Among them, Pm is the debugging instruction, Uref is the voltage given signal, P is the active power, Q is the reactive power, Qref is the reactive rated value, P virtual is the virtual power consumed by the virtual load Rv, P real is the real power output by the energy storage converter, K Qis the droop coefficient, E* is the internal potential amplitude, Ud_ref is the voltage parameter, ω* is the angular frequency, s represents the response of the system to the time derivative of the input signal, θ is the impedance angle, Js is the moment of inertia, and D is the damping coefficient.

[0219] For example, on this basis, by executing the above step S1103, an equivalent circuit model corresponding to the energy storage system can be obtained as follows: Fig.18 As shown, Fig.18 Another structural schematic diagram of an equivalent circuit model of an energy storage system in the energy storage system control method provided in an embodiment of the present application, wherein u ref1 is the voltage given signal of the first battery cluster device, u ref2 is the voltage given signal of the second battery cluster device, i total1 for u ref1 The total current delivered, i total2 for u ref2 The total current delivered, i v1 is the virtual current flowing through the virtual load Rv1, i v2 is the virtual current flowing through the virtual load Rv2, i o1 is the output current of the energy storage converter of the first battery cluster device, i o2 is the output current of the energy storage converter of the second battery cluster device, Z load is the real line impedance, Z eq It is the sum of the equivalent line impedance obtained by the control loop and the real line impedance. total1 is the total power generated by the first battery cluster device, P total2 is the total power generated by the second battery cluster device, P virtual1 is composed of a dummy load R v1 Virtual power consumed, P virtual2 is composed of a dummy load R v2 Virtual power consumed, P real1 is the real power generated by the energy storage converter of the first battery cluster device, P real2 It is the energy storage converter of the second battery cluster device that generates real power.

[0220] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the system and device described above can refer to the corresponding process in the method embodiment, and will not be repeated in this application. In the several embodiments provided in this application, it should be understood that the disclosed system, device and method can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0221] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or part of the technical solution that contributes to the prior art or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, RandomAccess Memory), disk or optical disk and other media that can store program code.

[0222] The above are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application.

Claims

1. A method for controlling an energy storage system, characterized in that: Applied to an energy storage system, the energy storage system at least comprises: a plurality of battery cluster devices connected in parallel, each of the battery cluster devices comprises a battery cluster unit and an energy storage converter, the method comprises: Acquiring a control mode of the energy storage system and a state of charge of each of the battery cluster units; According to the control mode and the preset virtual load, a total power balance formula of the energy storage system is determined, the virtual load is used to simulate the load in the energy storage system, the total power balance formula is used to characterize the conditions that the actual power of each battery cluster unit and the virtual power of the virtual load should satisfy when the power of each battery cluster unit is balanced, the preset virtual load is added based on the control mode of the energy storage system, and the preset virtual load includes: a virtual load corresponding to each battery cluster unit, and the resistance value of the virtual load corresponding to each battery cluster unit is positively correlated with the charge state of each battery cluster unit; According to the total power balance formula and the charge state of each battery cluster unit, each battery cluster unit is controlled to be charged and discharged.

2. The energy storage system control method according to claim 1, characterized in that: The controlling each of the battery cluster units to charge and discharge according to the total power balance formula and the charge state of each of the battery cluster units comprises: Determining the resistance value of the virtual load corresponding to each of the battery cluster units according to the charge state of each of the battery cluster units; Determine the actual power corresponding to each of the battery cluster units according to the total power balance formula and the resistance value of the virtual load corresponding to each of the battery cluster units; According to the actual power corresponding to each battery cluster unit, each battery cluster unit is controlled to be charged and discharged.

3. The energy storage system control method according to claim 2, characterized in that: The step of determining the resistance of the virtual load corresponding to each of the battery cluster units according to the charge state of each of the battery cluster units includes: Determine the maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each of the battery cluster units; The resistance value of the virtual load corresponding to each of the battery cluster units is determined according to the maximum resistance value of the virtual load corresponding to each of the battery cluster units, the minimum resistance value of the virtual load and the charge state of each of the battery cluster units.

4. The energy storage system control method according to claim 3, characterized in that: The determining of the maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each of the battery cluster units includes: Determine the total power of the current battery cluster units; According to the total power, a maximum resistance value of a virtual load and a minimum resistance value of a virtual load corresponding to the current battery cluster unit are determined.

5. The energy storage system control method according to claim 3, characterized in that: The determining of the maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each of the battery cluster units includes: Obtaining system parameters of the energy storage system; According to the system parameters of the energy storage system, the maximum resistance value of the virtual load and the minimum resistance value of the virtual load corresponding to each of the battery cluster units are determined.

6. The energy storage system control method according to claim 2, characterized in that: The determining the actual power corresponding to each of the battery cluster units according to the total power balance formula and the resistance value of the virtual load corresponding to each of the battery cluster units includes: Determining the virtual power corresponding to each of the battery cluster units according to the resistance value of the virtual load corresponding to each of the battery cluster units; The virtual power value of each battery cluster unit is input into the total power balance formula of the energy storage system to determine the actual power corresponding to each battery cluster unit.

7. The energy storage system control method according to claim 1, characterized in that: The controlling each of the battery cluster units to charge and discharge according to the total power balance formula and the charge state of each of the battery cluster units comprises: Determining the virtual power corresponding to each of the battery cluster units according to the charge state of each of the battery cluster units; Determine the actual power corresponding to each of the battery cluster units according to the total power balance formula and the virtual power corresponding to each of the battery cluster units; According to the actual power corresponding to each battery cluster unit, each battery cluster unit is controlled to be charged and discharged.

8. The energy storage system control method according to claim 7, characterized in that: The step of determining the virtual power corresponding to each of the battery cluster units according to the state of charge of each of the battery cluster units includes: Determine a virtual load maximum power value and a virtual load minimum power value corresponding to each of the battery cluster units; The virtual power corresponding to each of the battery cluster units is determined according to the charge state of each of the battery cluster units, the maximum power value of the virtual load, and the minimum power value of the virtual load.

9. The energy storage system control method according to claim 8, characterized in that: The determining of the virtual load maximum power value and the virtual load minimum power value corresponding to each of the battery cluster units includes: Acquiring the actual power of each of the battery cluster units; According to the actual power of each battery cluster unit, a virtual load maximum power value and a virtual load minimum power value corresponding to each battery cluster unit are determined.

10. The energy storage system control method according to claim 1, characterized in that: Determining the total power balance formula of the energy storage system according to the control mode and the preset virtual load includes: Constructing an equivalent circuit model of the energy storage system according to the control mode and the preset virtual load; According to the equivalent circuit model, a total power balance formula of the energy storage system is determined.

11. The energy storage system control method according to claim 10, characterized in that: The step of constructing an equivalent circuit model of the energy storage system according to the control mode and the preset virtual load includes: determining an initial closed-loop control structure of the energy storage system; Adding a preset virtual load to the initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system; An equivalent circuit model of the energy storage system is generated according to the target closed-loop control structure.

12. The energy storage system control method according to claim 11, characterized in that: The initial closed-loop control structure is a first initial closed-loop control structure; The step of adding a preset virtual load to the initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system includes: A preset virtual load is added to both ends of the output voltage of the inverter in the first initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system.

13. The energy storage system control method according to claim 11, characterized in that: The initial closed-loop control structure is a second initial closed-loop control structure; The step of adding a preset virtual load to the initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system includes: A preset virtual load is added across the voltage in the second initial closed-loop control structure to obtain a target closed-loop control structure of the energy storage system.

14. An energy storage system, characterized in that: include: A plurality of battery cluster devices connected in parallel and a control device, wherein the control device is used to execute the energy storage system control method according to any one of claims 1 to 13.

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