Energy storage system control method and energy storage system

Abstract

Disclosed in the present application are an energy storage system control method and an energy storage system. The energy storage system control method of the present application comprises: on the basis of a remaining discharge capacity of an energy storage battery pack and a total remaining discharge capacity of an energy storage system, controlling the magnitude adjustment for the output power of each energy storage inverter; performing sampling on an output voltage of the energy storage inverter, and acquiring an output voltage mode value of the energy storage inverter; and performing compensation on the output voltage of the energy storage inverter on the basis of the output voltage mode value and the output power corresponding to the energy storage inverter. Distinguished from the prior art, the control method of the present application uses an output voltage mode value as a feedback quantity to perform compensation on an output voltage of an energy storage inverter. Compared with an output voltage effective value used in the prior art, the output voltage mode value has a shorter acquisition period, and a control module can instantly acquire the output voltage mode value of the energy storage inverter to perform compensation on the output voltage of the energy storage inverter, such that the dynamic voltage response characteristic of an energy storage system is improved, thereby further improving the stability of the energy storage system.

Description

Energy storage system control method and energy storage system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 2024102267699, filed on February 28, 2024, entitled “A control method for an energy storage system and an energy storage system,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the technical field of energy storage system charging and discharging, and in particular to a control method for an energy storage system and an energy storage system. Background Art

[0004] Single-phase off-grid energy storage systems generally consist of several energy storage subsystems and loads. Each energy storage subsystem consists of batteries, a BMS (battery management system), and an energy storage inverter. When the battery discharges to the load through the energy storage inverter, the RMS output voltage of the energy storage inverter will deviate from the rated voltage due to the off-grid droop and parallel control scheme used by the energy storage system. Common inverter output voltage compensation methods use AC voltage RMS compensation control methods. However, since the AC voltage RMS value is updated once per power frequency cycle, this control method suffers from poor dynamic AC voltage response. Summary of the Invention

[0005] The present application provides a control method for an energy storage system to solve the above technical problems. The energy storage system includes multiple energy storage battery packs, multiple control modules, and multiple energy storage inverters. Each of the control modules is connected to a corresponding energy storage battery pack, and the corresponding energy storage battery pack is connected to an external load through a corresponding energy storage inverter. Each of the control modules, the corresponding energy storage battery pack, and the corresponding energy storage inverter constitute an energy storage subsystem. The energy storage system includes multiple energy storage subsystems. The control method is applied to the energy storage system, and the control method includes:

[0006] Obtaining the remaining discharge capacity of the energy storage battery group in each of the energy storage subsystems, and controlling the adjustment of the output power of the energy storage inverter corresponding to each energy storage battery group based on the obtained remaining discharge capacity of all the energy storage battery groups and the total remaining discharge capacity of the energy storage system; wherein the total remaining discharge capacity of the energy storage system is the sum of the remaining discharge capacity of all the energy storage battery groups;

[0007] In each of the energy storage subsystems, the output voltage of the corresponding energy storage inverter is sampled to obtain the output voltage modulus of the energy storage inverter; and the output voltage of the energy storage inverter is compensated based on the output voltage modulus and the output power corresponding to the energy storage inverter.

[0008] The step of sampling the output voltage of the corresponding energy storage inverter to obtain the output voltage modulus of the energy storage inverter includes:

[0009] Obtaining a first preset value and a second preset value of the output voltage based on the output voltage, and obtaining the output voltage modulus based on the first preset value and the second preset value;

[0010] The output voltage modulus is equal to the square root of the sum of the square of the first preset value and the square of the second preset value.

[0011] The product of the value obtained after Laplace transformation and the calculated first coefficient is obtained, and the second preset value is the product of the value obtained after Laplace transformation of the output voltage and the calculated second coefficient.

[0012] The first coefficient and the second coefficient are two values ​​obtained by different calculation methods of the compensation coefficient, the complex parameter and the angular velocity of the output voltage;

[0013] The compensation coefficient is the product of square root of 2 and the equivalent impedance, and the equivalent impedance is the equivalent impedance of the circuit between the energy storage inverter and the load; and the complex parameter is the complex parameter used in the Laplace transform of the output voltage.

[0014] The step of compensating the output voltage of the energy storage inverter based on the output voltage modulus and the output power corresponding to the energy storage inverter includes:

[0015] Obtaining a voltage compensation value of the energy storage inverter based on the output power and the output voltage modulus;

[0016] The output voltage of the energy storage inverter is compensated based on the voltage compensation value.

[0017] The voltage compensation value is positively correlated with the output power and negatively correlated with the output voltage modulus.

[0018] The step of controlling the output power of the energy storage inverter corresponding to each energy storage battery group based on the obtained remaining discharge power of all the energy storage battery groups and the total remaining discharge power of the energy storage system includes:

[0019] Obtaining the output power of the energy storage system;

[0020] Based on the total discharge residual power of the energy storage system and the discharge residual power of each of the energy storage battery groups, obtaining the discharge residual power weight of each of the energy storage battery groups; wherein the discharge residual power of the energy storage battery group is obtained based on the residual power of the energy storage battery group and the preset residual power;

[0021] Based on the discharge residual power weight of the energy storage battery group and the output power of the energy storage system, the output power of the energy storage inverter corresponding to each energy storage battery group is controlled to be adjusted.

[0022] The step of obtaining the output power of the energy storage system includes:

[0023] The output power of each of the energy storage inverters is obtained, and the obtained output powers of all the energy storage inverters are added together to obtain the output power of the energy storage system.

[0024] The control method further includes:

[0025] Based on the obtained remaining power of the energy storage battery pack and the preset remaining power, the remaining discharge power of each of the energy storage battery packs is obtained, and the remaining discharge power of all the energy storage battery packs is added together to obtain the total remaining discharge power of the energy storage system.

[0026] The remaining discharge capacity of the energy storage battery pack is equal to the difference between the remaining capacity of the energy storage battery pack and the preset remaining capacity.

[0027] The step of obtaining the weight of the remaining discharge capacity of each energy storage battery group based on the total remaining discharge capacity of the energy storage system and the remaining discharge capacity of each energy storage battery group includes:

[0028] Obtaining the rated power and the remaining discharge power corresponding to each of the energy storage battery packs;

[0029] The product of the remaining discharge capacity of each energy storage battery group and the corresponding rated capacity is divided by the sum of the products of the remaining discharge capacity of all the energy storage battery groups and the corresponding rated capacity to obtain the remaining discharge capacity weight of each energy storage battery.

[0030] The output power of the energy storage inverter is the product of the discharge residual power weight of the corresponding energy storage battery group and the output power of the energy storage system.

[0031] The control method further includes:

[0032] Obtaining the remaining charge of the energy storage battery group in each of the energy storage subsystems, and based on the remaining charge weight of each energy storage battery group in the total remaining charge of the energy storage system, controlling the adjustment of the output power of the energy storage inverter corresponding to each energy storage battery group, and charging the energy storage battery group;

[0033] The total remaining charge of the energy storage system is the sum of the remaining charge of all the energy storage battery packs.

[0034] The step of obtaining the remaining charge of the energy storage battery pack in each of the energy storage subsystems includes:

[0035] Based on the acquired remaining power of each energy storage battery pack and the preset charging power, the charging remaining power of the energy storage battery pack is obtained.

[0036] The control method further includes:

[0037] Obtaining the rated power and the remaining charge power corresponding to each of the energy storage battery packs;

[0038] The product of the remaining charge capacity of each energy storage battery group and the corresponding rated capacity is divided by the sum of the products of the remaining charge capacity of all the energy storage battery groups and the corresponding rated capacity to obtain the remaining charge capacity weight of each energy storage battery group.

[0039] The output power of the energy storage inverter is the product of the remaining charge weight of the corresponding energy storage battery group and the output power of the energy storage system.

[0040] In order to solve the above technical problems, the present application also provides an energy storage system, which includes a photovoltaic power generation module and multiple energy storage subsystems, each of which includes an energy storage battery pack, an energy storage inverter and a control module, wherein the control module is connected to the corresponding energy storage inverter, the energy storage battery pack is connected to an external load through the corresponding energy storage inverter, and the photovoltaic power generation module is connected to the corresponding energy storage battery pack through the energy storage inverter. The control module performs the following steps to control the energy storage battery pack to charge and discharge:

[0041] Obtaining the remaining discharge capacity of the energy storage battery group in each of the energy storage subsystems, and controlling the adjustment of the output power of the energy storage inverter corresponding to each energy storage battery group based on the obtained remaining discharge capacity of all the energy storage battery groups and the total remaining discharge capacity of the energy storage system; wherein the total remaining discharge capacity of the energy storage system is the sum of the remaining discharge capacity of all the energy storage battery groups;

[0042] In each of the energy storage subsystems, the output voltage of the corresponding energy storage inverter is sampled to obtain the output voltage modulus of the energy storage inverter; and the output voltage of the energy storage inverter is compensated based on the output voltage modulus and the output power corresponding to the energy storage inverter.

[0043] The step of sampling the output voltage of the corresponding energy storage inverter to obtain the output voltage modulus of the energy storage inverter includes:

[0044] Obtaining a first preset value and a second preset value of the output voltage based on the output voltage, and obtaining the output voltage modulus based on the first preset value and the second preset value;

[0045] The output voltage modulus is equal to the square root of the sum of the square of the first preset value and the square of the second preset value.

[0046] The step of compensating the output voltage of the energy storage inverter based on the output voltage modulus and the output power corresponding to the energy storage inverter includes:

[0047] Obtaining a voltage compensation value of the energy storage inverter based on the output power and the output voltage modulus;

[0048] The output voltage of the energy storage inverter is compensated based on the voltage compensation value.

[0049] The step of controlling the output power of the energy storage inverter corresponding to each energy storage battery group based on the obtained remaining discharge power of all the energy storage battery groups and the total remaining discharge power of the energy storage system includes:

[0050] Obtaining the output power of the energy storage system;

[0051] Based on the total discharge residual power of the energy storage system and the discharge residual power of each of the energy storage battery groups, obtaining the discharge residual power weight of each of the energy storage battery groups; wherein the discharge residual power of the energy storage battery group is obtained based on the residual power of the energy storage battery group and the preset residual power;

[0052] Based on the discharge residual power weight of the energy storage battery group and the output power of the energy storage system, the output power of the energy storage inverter corresponding to each energy storage battery group is controlled to be adjusted.

[0053] The control method further includes:

[0054] Obtaining the remaining charge of the energy storage battery group in each of the energy storage subsystems, and based on the remaining charge weight of each energy storage battery group in the total remaining charge of the energy storage system, controlling the adjustment of the output power of the energy storage inverter corresponding to each energy storage battery group, and charging the energy storage battery group;

[0055] The total remaining charge of the energy storage system is the sum of the remaining charge of all the energy storage battery packs.

[0056] Beneficial effects of the present application: Different from the prior art, the control method of the energy storage system of the present application includes: controlling the adjustment of the output power of the energy storage inverter of each energy storage subsystem based on the remaining discharge capacity of the energy storage battery group and the total remaining discharge capacity of the energy storage system; sampling the output voltage of the energy storage inverter to obtain the output voltage modulus of the energy storage inverter; and compensating the output voltage of the energy storage inverter based on the output voltage modulus and the output power corresponding to the energy storage inverter. Different from the prior art, the control method of the present application uses the output voltage modulus as a feedback quantity to compensate for the output voltage of the energy storage inverter. Compared with the output voltage effective value used in the prior art, the output voltage modulus acquisition cycle is shorter, and the control module can instantly obtain the output voltage modulus of the energy storage inverter to compensate for the output voltage of the energy storage inverter, thereby improving the voltage dynamic response characteristics of the energy storage system and further improving the stability of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without inventive efforts. Among them:

[0058] FIG1 is a schematic diagram of the system structure of a first embodiment of an energy storage system provided by the present application;

[0059] FIG2 is a flow chart of a first embodiment of a control method provided by the present application;

[0060] FIG3 is a schematic diagram of a flow chart of a first embodiment of step S2 in FIG2 ;

[0061] FIG4 is a schematic diagram of a flow chart of a first embodiment of step S3 in FIG2 ;

[0062] FIG5 is a schematic diagram of a flow chart of a first embodiment of step S1 in FIG2 ;

[0063] FIG6 is a flow chart of a second embodiment of the control method provided in this application.

[0064] Reference numerals: energy storage system 1; energy storage battery pack 11; control module 12; energy storage inverter 13; photovoltaic power generation module 14; load 2. DETAILED DESCRIPTION

[0065] The following describes the embodiments of the present application in detail with reference to the accompanying drawings.

[0066] In the following description, for the purpose of explanation rather than limitation, specific details such as specific system structures, interfaces, and technologies are provided to facilitate a thorough understanding of the present application.

[0067] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0068] The term "and / or" in this application is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent three situations: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the objects associated before and after are in an "or" relationship. In addition, "many" in this article means two or more than two. In addition, the term "at least one" in this article means any combination of at least two of any one or more of a plurality of, for example, including at least one of A, B, and C, can mean including any one or more elements selected from the set consisting of A, B, and C. In addition, the terms "first", "second", and "third" in this application are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated.

[0069] Please refer to Figure 1, which is a system structure diagram of the first embodiment of the energy storage system provided in this application. The energy storage system 1 includes multiple energy storage battery groups 11, multiple control modules 12 and multiple energy storage inverters 13. Each control module 12 is connected to the corresponding energy storage battery group 11, and the energy storage battery group 11 is connected to the external load 2 through the corresponding energy storage inverter 13. Among them, the energy storage battery group 11 and its corresponding control module 12 and energy storage inverter 13 constitute an energy storage subsystem, that is, the energy storage system 1 includes multiple energy storage subsystems. Then, the control module 12 can control the energy storage battery group 11 in each energy storage subsystem to discharge to the external load 2 through the corresponding energy storage inverter 13. The energy storage inverter 13 is used to convert the direct current output by the energy storage battery group 11 into alternating current to power the load 2.

[0070] Among them, the energy storage battery group 11 in each energy storage subsystem may include one energy storage battery or multiple energy storage batteries. When only one energy storage battery is included, the energy storage battery is discharged through the corresponding energy storage inverter 13; when multiple energy storage batteries are included, multiple energy storage batteries are discharged through the same energy storage inverter 13.

[0071] Existing energy storage systems typically employ an off-grid droop and parallel control scheme, specifically including the following steps: 1. Voltage and active power droop; 2. Frequency and active power droop; 3. Virtual reactance; 4. AC voltage amplitude compensation; 5. AC voltage DC component control; 6. AC instantaneous voltage control closed loop; 7. Inductor current control closed loop; 8. Energy storage inverter AC voltage amplitude control closed loop. Load 2 can be a variety of household appliances.

[0072] In step 1, when the energy storage battery pack is connected to the load via the energy storage inverter, the droop control process causes the effective value of the AC voltage output by the energy storage inverter to deviate from the rated voltage (the rated voltage can be the nominal voltage for normal load operation, such as 220V or 380V). Furthermore, in step 3, according to Ohm's law, the output current of the energy storage inverter will produce a virtual voltage drop across the virtual reactance, which also causes the effective value of the AC voltage output by the energy storage inverter to deviate from the rated voltage. Therefore, in step 4, the AC voltage amplitude output by the energy storage inverter needs to be compensated.

[0073] In the prior art, the feedback value for compensating the output voltage of the energy storage inverter is the effective value of the output voltage of the energy storage inverter. To obtain the effective value of the output voltage of the energy storage inverter, it is necessary to collect the output voltage of the energy storage inverter within one cycle and obtain the effective value after calculation. The cycle for obtaining the effective value of the output voltage is long, and the dynamic response of the voltage control is slow.

[0074] Please refer to Figure 2, which is a flow chart of the first embodiment of the control method provided by this application. The control method provided by this embodiment of the application is applied to the energy storage system 1, and specifically includes the following steps:

[0075] S1: Obtain the remaining discharge capacity of each energy storage battery group 11, and based on the obtained remaining discharge capacity of all energy storage battery groups 11 and the total remaining discharge capacity of the energy storage system 1, control the adjustment of the output power of the energy storage inverter 13 corresponding to each energy storage battery group 11.

[0076] In this embodiment, the control module 12 may first obtain the current remaining discharge capacity of each energy storage battery group 11, and add up the remaining discharge capacities of all energy storage battery groups 11. The sum of the remaining discharge capacities of all energy storage battery groups 11 obtained is the total remaining discharge capacity of the energy storage system 1. Based on the remaining discharge capacity of the energy storage battery groups 11 and the total remaining discharge capacity of the energy storage system 1, the control module 12 may obtain the weight of the remaining discharge capacity of each energy storage battery group 11 in the total remaining discharge capacity of the energy storage system 1, and control the output power of the energy storage inverter 13 corresponding to each energy storage battery group 11. The energy storage battery group 11 discharges to the load 2 through the energy storage inverter 13. The energy storage inverter 13 is used to convert the DC voltage output by the energy storage battery group 11 into an AC voltage to power the load 2.

[0077] S2: Sampling the output voltage of the energy storage inverter 13 to obtain the output voltage modulus of the energy storage inverter 13 .

[0078] Furthermore, in each energy storage subsystem, the corresponding control module 12 can also be connected to the energy storage inverter 13 to sample the output voltage of the energy storage inverter 13, and then obtain the output voltage modulus of the energy storage inverter 13 based on the output voltage of the energy storage inverter 13.

[0079] Among them, the output voltage modulus of the energy storage inverter 13 does not need to be collected for one cycle of the output voltage of the energy storage inverter 13, which has better immediacy and can quickly respond to the output voltage of the energy storage inverter 13, thereby improving the voltage dynamic response characteristics of the control method provided in this embodiment.

[0080] S3: Based on the output voltage modulus and the output power corresponding to the energy storage inverter 13 , the output voltage of the energy storage inverter 13 is compensated.

[0081] In step S2, after the control module 12 obtains the output voltage modulus of the energy storage inverter 13, it can use the output voltage modulus as a feedback quantity and compensate the output voltage of the energy storage inverter 13 based on the output voltage modulus, so that the output voltage of the energy storage inverter 13 is stabilized near the rated voltage value, thereby improving the stability of the energy storage system 1.

[0082] Specifically, this embodiment proposes a voltage drop compensation method based on the active power tracking of the energy storage inverter 13. The active current output by the energy storage inverter 13 can be calculated through the active power and output voltage modulus output by the energy storage inverter 13. The active current is multiplied by the virtual reactance generated in step 3 of the off-grid droop parallel control method, and this product is superimposed on the AC voltage modulus control loop to compensate for the voltage drop caused by the active current on the virtual reactance.

[0083] In actual applications, the energy storage inverter 13 includes capacitors and inductors. Therefore, in the process of converting the DC voltage of the energy storage battery group 11 into AC voltage, the energy storage inverter 13 will generate active power and reactive power. The control module 12 obtains the real-time active power output by the energy storage inverter 13 based on the real-time output voltage of the energy storage inverter 13. The output power of the energy storage inverter 13 described here and below is the real-time active power output by the energy storage inverter 13.

[0084] In summary, unlike the prior art, the control method of the present application uses the output voltage modulus as a feedback quantity to compensate for the output voltage of the energy storage inverter 13. Compared with the output voltage effective value, the output voltage modulus acquisition cycle is shorter. The control module 12 can instantly obtain the output voltage modulus of the energy storage inverter 13 to compensate for the output voltage of the energy storage inverter 13, thereby improving the voltage dynamic response characteristics of the control method and further improving the stability of the energy storage system 1.

[0085] At the same time, the output power of the corresponding energy storage inverter 13 is adjusted based on the discharge residual power weight of each energy storage battery group 11. This avoids the situation in current energy storage systems where each energy storage inverter operates at the same output power, resulting in energy storage battery groups with different residual powers discharging the load at the same power, causing some energy storage battery groups to over-discharge while others to incompletely discharge, thereby shortening the lifespan of the energy storage battery groups. The control module 12 controls the output power of the energy storage inverter 13 corresponding to the energy storage battery group 11 based on the discharge residual power of the energy storage battery group 11 and the total discharge residual power of the energy storage system 1, ensuring that multiple energy storage battery groups 11 in the energy storage system 1 can discharge simultaneously during the discharge process, thereby ensuring the service life of the energy storage battery groups 11 in the energy storage system 1.

[0086] Please refer to Figure 3, which is a flow chart of the first embodiment of step S2 in Figure 2. In step S2, the output voltage of the energy storage inverter 13 is sampled, and the specific steps of obtaining the output voltage modulus of the energy storage inverter 13 include:

[0087] S31: Obtaining a first preset value and a second preset value of the output voltage based on the output voltage.

[0088] The first preset value is the product of the value obtained after Laplace transform of the output voltage and the calculated first coefficient. The first coefficient is a value obtained by calculating the compensation coefficient, the complex parameter used in the Laplace transform of the output voltage, and the angular velocity of the output voltage. Specifically, the first preset value can be expressed as:

[0089] Where k is the compensation coefficient ( Z vicis the equivalent impedance of the circuit between the energy storage inverter 13 and the load 2); s is the complex parameter in the Laplace transform, ω is the angular velocity of the output voltage, and Vac(s) is the output voltage.

[0090] The second preset value is the product of the Laplace transformed value of the output voltage and the second coefficient. The second coefficient is a value obtained by calculating the compensation coefficient, the complex parameter used in the Laplace transform of the output voltage, and the angular velocity of the output voltage. Specifically, the second preset value can be expressed as:

[0091] Where k is the compensation coefficient; s is the complex parameter in the Laplace transform, ω is the angular velocity of the output voltage, and Vac(s) is the output voltage.

[0092] Since the output voltage of the energy storage inverter 13 is an AC voltage, in one embodiment, the first preset value D(s) and the second preset value Q(s) can be considered as a pair of orthogonal quantities output after the output voltage Vac(s) is processed by a second-order generalized integrator.

[0093] S32: Obtain an output voltage modulus based on the first preset value and the second preset value.

[0094] Furthermore, after obtaining the first preset value D(s) and the second preset value Q(s) in step S31, the control module 12 may calculate the output voltage modulus of the energy storage inverter 13. Specifically, the output voltage modulus of the energy storage inverter 13 is equal to the square root of the sum of the square value of the first preset value D(s) and the square value of the second preset value Q(s). This can be expressed as:

[0095] Wherein, Vac_amp(s) is the output voltage modulus, D(s) is the first preset value, and Q(s) is the second preset value.

[0096] In summary, based on the output voltage of the energy storage inverter 13, the first preset value and the second preset value of the orthogonal quantity are obtained, and based on the first preset value and the second preset value, the output voltage modulus of the energy storage inverter 13 is obtained. There is no need to collect the output voltage of the energy storage inverter 13 for one cycle, and the output voltage modulus acquisition cycle is short. The control module 12 can compensate for the output voltage of the energy storage inverter 13 based on the quickly obtained output voltage modulus, thereby improving the voltage dynamic response characteristics of the control method.

[0097] Further, please refer to Figure 4, which is a flow chart of the first embodiment of step S3 in Figure 2. In step S3, the specific steps of compensating the output voltage of the energy storage inverter 13 based on the output voltage modulus and output power include:

[0098] S41: Based on the output power and the voltage output modulus, a voltage compensation value of the energy storage inverter 13 is obtained.

[0099] In this embodiment, the voltage compensation value may be positively correlated with the output power of the energy storage inverter 13 and negatively correlated with the output voltage modulus. Specifically, the voltage compensation value may be expressed by formula (4):

[0100] Wherein, Vac_amp_comp(s) is the voltage compensation value, P is the real-time active power output by the energy storage inverter 13, k is the compensation coefficient, and Vac_amp(s) is the output voltage modulus.

[0101] Furthermore, the control module 12 can compensate the output voltage of the energy storage inverter 13 according to the output power and output voltage modulus of the energy storage inverter 13 , thereby improving the stability of the energy storage system 1 .

[0102] S42: Compensate the output voltage of the energy storage inverter 13 according to the voltage compensation value.

[0103] In step S41, after the control module 12 obtains the voltage compensation value of the energy storage inverter 13 based on the output power and output voltage modulus of the energy storage inverter 13, it can compensate the output voltage of the energy storage inverter 13 according to the voltage compensation value, so that the output voltage of the energy storage inverter 13 is stabilized near the rated voltage value, thereby improving the stability of the energy storage system 1.

[0104] Further, please refer to Figure 5, which is a flow chart of the first embodiment of step S1 in Figure 2. Since the energy storage system 1 includes multiple energy storage subsystems, each energy storage subsystem includes an energy storage battery group 11. When the control module 12 controls the energy storage battery group 11 to discharge to the load 2, the multiple energy storage battery groups 11 will discharge simultaneously, and the rated power and remaining power of each energy storage battery group 11 may be different. Therefore, in step S1, based on the remaining discharge power of the energy storage battery group 11 and the total remaining discharge power of the energy storage system 1, the adjustment of the output power of the energy storage inverter 13 corresponding to each energy storage battery group 11 specifically includes the following steps:

[0105] S51: Obtain the output power of the energy storage system 1.

[0106] The output power of the energy storage system 1 may be obtained by obtaining the output power of each of the energy storage inverters 13 , and adding the obtained output powers of all the energy storage inverters 13 to obtain the output power of the energy storage system 1 .

[0107] In this embodiment, all control modules 12 in the energy storage system 1 can obtain the output power of the corresponding energy storage inverter 13, and thus one of the control modules 12 can receive the output power of all energy storage inverters 13 in the energy storage system 1. The output power of all energy storage inverters 13 obtained is added together to obtain the output power of the energy storage system 1. As described above, each control module 12 and its corresponding energy storage battery pack 11 and energy storage inverter 13 constitute an energy storage subsystem. The output power of the energy storage inverter 13 is also the output power of the energy storage subsystem. Thus, the output power of the energy storage system 1 can be the sum of the output power of all energy storage subsystems in the energy storage system 1. That is, the sum of the output power of all energy storage inverters 13 is the output power of the energy storage system 1.

[0108] In other embodiments, the energy storage system 1 may further include a control unit, which is connected to all the control modules 12. After the control module 12 obtains the output power of the corresponding energy storage inverter 13, the output power of the corresponding energy storage inverter 13 can be transmitted to the control unit. The control unit receives the output power of the energy storage inverter 13 transmitted from all the control modules 12, and adds the output power of all the energy storage inverters 13 to obtain the output power of the energy storage system 1.

[0109] S52 : Based on the total discharge residual capacity of the energy storage system 1 and the discharge residual capacity of each energy storage battery group 11 , obtain the discharge residual capacity weight of each energy storage battery group 11 .

[0110] Among them, the control module 12 can first obtain the discharge residual power of each energy storage battery group 11 based on the remaining power of the energy storage battery group 11 and the preset remaining power, and add up the discharge residual power of all the energy storage battery groups 11 to obtain the total discharge residual power of the energy storage system 1.

[0111] The preset remaining power may be the lower discharge limit of the energy storage battery pack 11, such as 10% of the rated power of the energy storage battery pack 11, or 5% of the rated power. When the energy storage battery pack 11 is discharged to the preset remaining power, the control module 12 may control the energy storage battery pack 11 to stop discharging, thereby preventing the energy storage battery pack 11 from completely discharging its stored power, thereby damaging the energy storage battery pack 11 and shortening its service life.

[0112] Furthermore, since the rated capacity and remaining capacity of each energy storage battery group 11 may be different, each control module 12 can obtain the remaining capacity and preset remaining capacity of the corresponding energy storage battery group 11, and based on the remaining capacity and preset remaining capacity of the energy storage battery group 11, obtain the discharge remaining capacity of each energy storage battery group 11 (the discharge remaining capacity of the energy storage battery group 11 is the difference between the remaining capacity of the energy storage battery group 11 and the preset remaining capacity). Then, the control module 12 can add up the discharge remaining capacity of all energy storage battery groups 11 to obtain the total discharge remaining capacity of the energy storage system 1. Among them, since the energy storage system 1 is powered by the discharge of the energy storage battery group 11 to supply power to the load 2, the sum of the discharge remaining capacity of all energy storage battery groups 11 in the energy storage system 1 is the discharge remaining capacity of the energy storage system 1.

[0113] Then, the control module 12 can obtain the rated power and the remaining discharge power of the corresponding energy storage battery group 11, divide the product of the remaining discharge power of each energy storage battery group 11 and the corresponding rated power by the sum of the products of the remaining discharge power of all energy storage battery groups 11 and the corresponding rated power, and obtain the remaining discharge power weight of each energy storage battery group 11.

[0114] S53 : Based on the discharge residual power weight of the energy storage battery group 11 and the output power of the energy storage system 1 , control the adjustment of the output power of the energy storage inverter 13 corresponding to each energy storage battery group 11 .

[0115] Furthermore, the control module 12 may obtain the output power corresponding to each energy storage battery group 11 based on the remaining discharge power weight of each energy storage battery group 11 in the energy storage system 1 and the output power of the energy storage system 1 obtained in step S53. Specifically, the output power of each energy storage inverter 13 may be the product of the remaining discharge power weight of each energy storage battery group 11 and the output power of the energy storage system 1, which may be expressed as the following formula:

[0116] Among them, P sum is the total active power output by all energy storage inverters 13 in the energy storage system 1; P ref_i is the output power corresponding to the i-th energy storage battery group 11 (i is an integer, 1≤i≤n); Q i is the rated capacity of the i-th energy storage battery pack 11 (i is an integer, 1≤i≤n); SOC i is the remaining capacity of the i-th energy storage battery pack 11; SOC lowerlimit It is the preset remaining power of the energy storage battery pack 11.

[0117] Then, each control module 12 can control the corresponding energy storage inverter 13 to output at the calculated output power based on the calculation result, so that the energy storage battery group 11 discharges the load 2. Among them, since the weight of the discharge residual power of each energy storage battery group 11 in the energy storage system 1 will be different based on its own discharge residual power, the output power of the energy storage inverter 13 obtained based on the discharge residual power weight will also be different. The output power of the energy storage inverter 13 corresponding to the energy storage battery group 11 with a large discharge residual power weight will be relatively large, while the output power of the energy storage inverter 13 corresponding to the energy storage battery group 11 with a small discharge residual power weight will be relatively small. Then, the control module 12 can control the discharge of the energy storage battery group 11 based on the discharge residual power of the energy storage battery group 11, avoiding the situation in the prior art where all energy storage batteries are discharged at the same output power, but the energy storage batteries with a small discharge residual power are exhausted faster, which shortens the life of the energy storage batteries.

[0118] In the embodiment of the present application, the control module 12 controls the output power of each energy storage battery pack 11 based on the remaining discharge capacity of each energy storage battery pack 11, so that all energy storage battery packs 11 in the energy storage system 1 can reach the preset remaining capacity at substantially the same time, thus avoiding the situation where some energy storage battery packs 11 are exhausted while others have remaining capacity. This improves the stability of the energy storage system 1, ensures the service life of the energy storage battery packs 11, and enhances the load capacity of the energy storage system 1.

[0119] In other embodiments, please continue to refer to Figures 1 and 6. Figure 6 is a flow chart of the second embodiment of the control method provided by the present application. The energy storage system 1 provided by the present application also includes a photovoltaic power generation module 14, which is connected to the energy storage battery group 11 through the energy storage inverter 13. The photovoltaic power generation module 14 is used to generate current, and the energy storage inverter 13 converts the alternating current into direct current to charge the energy storage battery group 11 and replenish the power in the energy storage battery group 11. Specifically, the control method provided by the present application also includes the following steps:

[0120] S61: Obtain the remaining charge of the energy storage battery group 11 in each energy storage subsystem, and based on the remaining charge weight of the energy storage battery group 11 in the total remaining charge of the energy storage system 1, control the adjustment of the output power of the energy storage inverter 13 corresponding to each energy storage battery group 11 to charge the energy storage battery group 11.

[0121] As previously mentioned, during the discharge phase of the energy storage battery pack 11, if the energy storage battery pack 11 is completely discharged, the service life of the energy storage battery pack 11 will be shortened. Similarly, during the charging phase of the energy storage battery pack 11, if the energy storage battery pack 11 is completely charged, the chemical reaction within the energy storage battery pack 11 will become more active, accelerating the aging of the energy storage battery pack 11. Therefore, in this embodiment, a preset charging capacity is also provided. The preset charging capacity can be 90% of the rated capacity of the energy storage battery pack 11, for example. When the energy storage battery pack 11 reaches 90% of the rated capacity, charging of the energy storage battery pack 11 is stopped or the charging speed of the energy storage battery pack 11 is slowed down.

[0122] Among them, the control module 12 can obtain the remaining power and the preset charging power of the energy storage battery group 11, and then obtain the remaining charging power of the energy storage battery group 11. At the same time, the control module 12 can also calculate the remaining charging power weight of each energy storage battery group 11 in the remaining charging power of the energy storage system 1 (the total remaining charging power of the energy storage system 1 is the sum of the remaining charging power of multiple energy storage battery groups 11), and control the output power of the energy storage inverter 13 corresponding to the energy storage battery group 11 based on the remaining charging power weight of each energy storage battery group 11, so that the photovoltaic power generation module 14 charges the energy storage battery group 11, so that all the energy storage battery groups 11 in the energy storage system 1 can reach the preset charging power at the same time, avoiding the situation where some energy storage battery groups 11 are in a fully charged state for a long time while some energy storage battery groups 11 are not fully charged for a long time, thereby improving the practicality of the control method.

[0123] The control module 12 may first obtain the rated capacity and remaining charge capacity corresponding to each energy storage battery group 11, and then divide the product of the remaining charge capacity of each energy storage battery group 11 and the corresponding rated capacity by the sum of the products of the remaining charge capacity and the corresponding rated capacity of all energy storage battery groups 11 to obtain the remaining charge capacity weight of each energy storage battery group. The output power of the energy storage inverter 13 may be the product of the remaining charge capacity weight of the corresponding energy storage battery group 11 and the output power of the energy storage system 1.

[0124] Specifically, when the control module 12 controls the photovoltaic power generation module 14 to charge each energy storage battery group 11, the output power of the energy storage inverter 13 corresponding to the energy storage battery group 11 can be expressed as:

[0125] Among them, P sum is the total active power output by all energy storage inverters 13 in the energy storage system 1; P ref_i is the output power corresponding to the i-th energy storage battery group 11 (i is an integer, 1≤i≤n); Q iis the rated capacity of the i-th energy storage battery pack 11 (i is an integer, 1≤i≤n); SOC i is the remaining capacity of the i-th energy storage battery pack 11; SOC upperlimit It is the preset charging capacity of the energy storage battery pack 11.

[0126] In summary, the control method provided in the embodiment of the present application obtains the output voltage modulus of the energy storage inverter 13 based on the output voltage and output power of the energy storage inverter 13. There is no need to collect the output voltage of the energy storage inverter 13 for one cycle. The output voltage modulus acquisition cycle is short. The control module 12 can compensate for the output voltage of the energy storage inverter 13 based on the quickly obtained output voltage modulus, thereby improving the voltage dynamic response characteristics of the control method.

[0127] At the same time, the control module 12 can obtain the weight of the discharge residual power of each energy storage battery group 11 in the total discharge residual power of the energy storage system 1 based on the residual power of the corresponding energy storage battery group 11 and the preset residual power, and control the adjustment of the output power of the energy storage inverter 13 corresponding to each energy storage battery group 11 based on the weight, so that the energy storage battery group 11 discharges the load 2, ensuring that multiple energy storage battery groups 11 can reach the preset residual power at the same time, thereby enhancing the load capacity of the energy storage system 1.

[0128] Furthermore, the control module 12 can also control the adjustment of the output power of the corresponding energy storage inverter 13 based on the weight of the remaining charge of the corresponding energy storage battery group 11 in the total remaining charge of the energy storage system 1, so as to charge the energy storage battery group 11 and make multiple energy storage battery groups 11 in the energy storage system 1 fully charged at the same time, thereby improving the practicality of the control method.

[0129] The present application also provides an energy storage system 1. Please continue to refer to Figure 1. The energy storage system 1 includes multiple energy storage subsystems and a photovoltaic power generation module 14. The energy storage subsystem includes an energy storage battery group 11, a control module 12, and an energy storage inverter 13. The control module 12 is connected to the corresponding energy storage inverter 13. The energy storage battery group 11 is connected to the load 2 through the corresponding energy storage inverter 13. The photovoltaic power generation module 14 is connected to the corresponding energy storage battery group 11 through the energy storage inverter 13. Then, the control module 12 performs the following steps to control the energy storage battery group 11 to charge and discharge:

[0130] Obtaining the remaining discharge capacity of the energy storage battery group 11 in each energy storage subsystem, and controlling the adjustment of the output power of the energy storage inverter 13 corresponding to each energy storage battery group 11 based on the obtained remaining discharge capacity of all energy storage battery groups 11 and the total remaining discharge capacity of the energy storage system 1; wherein the total remaining discharge capacity of the energy storage system 1 is the sum of the remaining discharge capacity of all energy storage battery groups 11;

[0131] In each energy storage subsystem, the output voltage of the corresponding energy storage inverter 13 is sampled to obtain the output voltage modulus of the energy storage inverter 13; based on the output voltage modulus and the output power corresponding to the energy storage inverter 13, the output voltage of the energy storage inverter 13 is compensated.

[0132] The step of sampling the output voltage of the corresponding energy storage inverter 13 to obtain the output voltage modulus of the energy storage inverter 13 includes:

[0133] Obtaining a first preset value and a second preset value of the output voltage based on the output voltage, and obtaining an output voltage modulus based on the first preset value and the second preset value;

[0134] The output voltage modulus is equal to the square root of the sum of the square of the first preset value and the square of the second preset value.

[0135] The step of compensating the output voltage of the energy storage inverter 13 based on the output voltage modulus and the output power corresponding to the energy storage inverter 13 includes:

[0136] Based on the output power and the output voltage modulus, a voltage compensation value of the energy storage inverter 13 is obtained;

[0137] Based on the voltage compensation value, the output voltage of the energy storage inverter 13 is compensated.

[0138] The step of adjusting the output power of the energy storage inverter 13 corresponding to each energy storage battery group 11 based on the obtained remaining discharge power of all energy storage battery groups 11 and the total remaining discharge power of the energy storage system 1 includes:

[0139] Obtaining the output power of the energy storage system 1;

[0140] Based on the total discharge residual power of the energy storage system 1 and the discharge residual power of each energy storage battery group 11, the discharge residual power weight of each energy storage battery group 11 is obtained; wherein the discharge residual power of the energy storage battery group 11 is obtained based on the residual power of the energy storage battery group 11 and the preset residual power;

[0141] Based on the discharge residual power weight of the energy storage battery group 11 and the output power of the energy storage system 1 , the output power of the energy storage inverter 13 corresponding to each energy storage battery group 11 is controlled to be adjusted.

[0142] The control method further includes:

[0143] Obtaining the remaining charge of the energy storage battery group 11 in each energy storage subsystem, and based on the remaining charge weight of each energy storage battery group 11 in the total remaining charge of the energy storage system 1, controlling the adjustment of the output power of the energy storage inverter 13 corresponding to each energy storage battery group 11, and charging the energy storage battery group 11;

[0144] The total remaining charge capacity of the energy storage system 1 is the sum of the remaining charge capacities of all the energy storage battery packs 11 .

[0145] The specific steps and operations can be found in the control method embodiment described above and will not be described in detail here.

[0146] In other embodiments, the photovoltaic power generation module 14 may also be connected to the load 2 to directly generate current to power the load 2 .

[0147] The above description is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A control method for an energy storage system, characterized in that: The energy storage system includes multiple energy storage battery packs, multiple control modules, and multiple energy storage inverters. Each control module is connected to a corresponding energy storage battery pack, and the corresponding energy storage battery pack is connected to an external load through the corresponding energy storage inverter. Each control module, the corresponding energy storage battery pack, and the corresponding energy storage inverter constitute an energy storage subsystem. The energy storage system includes multiple energy storage subsystems. The control method is applied to the energy storage system, and the control method includes: Obtaining the remaining discharge capacity of the energy storage battery group in each of the energy storage subsystems, and controlling the adjustment of the output power of the energy storage inverter corresponding to each energy storage battery group based on the obtained remaining discharge capacity of all the energy storage battery groups and the total remaining discharge capacity of the energy storage system; wherein the total remaining discharge capacity of the energy storage system is the sum of the remaining discharge capacity of all the energy storage battery groups; In each of the energy storage subsystems, the output voltage of the corresponding energy storage inverter is sampled to obtain the output voltage modulus of the energy storage inverter; and the output voltage of the energy storage inverter is compensated based on the output voltage modulus and the output power corresponding to the energy storage inverter.

2. The control method according to claim 1, characterized in that: The step of sampling the output voltage of the corresponding energy storage inverter to obtain the output voltage modulus of the energy storage inverter includes: Obtaining a first preset value and a second preset value of the output voltage based on the output voltage, and obtaining the output voltage modulus based on the first preset value and the second preset value; The output voltage modulus is equal to the square root of the sum of the square of the first preset value and the square of the second preset value.

3. The control method according to claim 2, characterized in that: The first preset value is the product of a value obtained by Laplace transforming the output voltage and a calculated first coefficient, and the second preset value is the product of a value obtained by Laplace transforming the output voltage and a calculated second coefficient; The first coefficient and the second coefficient are two values ​​obtained by different calculation methods of the compensation coefficient, the complex parameter and the angular velocity of the output voltage; The compensation coefficient is the product of square root of 2 and the equivalent impedance, and the equivalent impedance is the equivalent impedance of the circuit between the energy storage inverter and the load; and the complex parameter is the complex parameter used in the Laplace transform of the output voltage.

4. The control method according to claim 1, wherein: The step of compensating the output voltage of the energy storage inverter based on the output voltage modulus and the output power corresponding to the energy storage inverter includes: Obtaining a voltage compensation value of the energy storage inverter based on the output power and the output voltage modulus; The output voltage of the energy storage inverter is compensated based on the voltage compensation value.

5. The control method according to claim 4, characterized in that: The voltage compensation value is positively correlated with the output power and negatively correlated with the output voltage modulus.

6. The control method according to claim 1, characterized in that: The step of controlling the output power of the energy storage inverter corresponding to each energy storage battery group based on the obtained remaining discharge power of all the energy storage battery groups and the total remaining discharge power of the energy storage system includes: Obtaining the output power of the energy storage system; Based on the total discharge residual power of the energy storage system and the discharge residual power of each of the energy storage battery groups, obtaining the discharge residual power weight of each of the energy storage battery groups; wherein the discharge residual power of the energy storage battery group is obtained based on the residual power of the energy storage battery group and the preset residual power; Based on the discharge residual power weight of the energy storage battery group and the output power of the energy storage system, the output power of the energy storage inverter corresponding to each energy storage battery group is controlled to be adjusted.

7. The control method according to claim 6, characterized in that: The step of obtaining the output power of the energy storage system includes: The output power of each of the energy storage inverters is obtained, and the obtained output powers of all the energy storage inverters are added together to obtain the output power of the energy storage system.

8. The control method according to claim 6, characterized in that: The control method further includes: Based on the acquired remaining power of the energy storage battery pack and the preset remaining power, the discharge remaining power of each of the energy storage battery packs is obtained, and the discharge remaining power of all the energy storage battery packs is added together to obtain the total discharge remaining power of the energy storage system.

9. The control method according to claim 8, characterized in that: The remaining discharge capacity of the energy storage battery pack is equal to the difference between the remaining capacity of the energy storage battery pack and the preset remaining capacity.

10. The control method according to claim 6, characterized in that: The step of obtaining the weight of the remaining discharge capacity of each energy storage battery group based on the total remaining discharge capacity of the energy storage system and the remaining discharge capacity of each energy storage battery group includes: Obtaining the rated power and the remaining discharge power corresponding to each of the energy storage battery packs; The product of the remaining discharge capacity of each energy storage battery group and the corresponding rated capacity is divided by the sum of the products of the remaining discharge capacity of all the energy storage battery groups and the corresponding rated capacity to obtain the remaining discharge capacity weight of each energy storage battery group.

11. The control method according to claim 10, characterized in that: The output power of the energy storage inverter is the product of the discharge residual power weight of the corresponding energy storage battery group and the output power of the energy storage system.

12. The control method according to claim 1, characterized in that: The control method further includes: Obtaining the remaining charge of the energy storage battery group in each of the energy storage subsystems, and based on the remaining charge weight of each energy storage battery group in the total remaining charge of the energy storage system, controlling the adjustment of the output power of the energy storage inverter corresponding to each energy storage battery group, and charging the energy storage battery group; The total remaining charge of the energy storage system is the sum of the remaining charge of all the energy storage battery packs.

13. The control method according to claim 12, characterized in that: The step of obtaining the remaining charge of the energy storage battery pack in each of the energy storage subsystems includes: Based on the acquired remaining power of each energy storage battery pack and the preset charging power, the charging remaining power of the energy storage battery pack is obtained.

14. The control method according to claim 12, characterized in that: The control method further includes: Obtaining the rated power and the remaining charge power corresponding to each of the energy storage battery packs; The product of the remaining charge capacity of each energy storage battery group and the corresponding rated capacity is divided by the sum of the products of the remaining charge capacity of all the energy storage battery groups and the corresponding rated capacity to obtain the remaining charge capacity weight of each energy storage battery group.

15. The control method according to claim 14, characterized in that: The output power of the energy storage inverter is the product of the remaining charge weight of the corresponding energy storage battery group and the output power of the energy storage system.

16. An energy storage system, characterized in that: The energy storage system includes a photovoltaic power generation module and multiple energy storage subsystems. Each of the energy storage subsystems includes an energy storage battery pack, an energy storage inverter, and a control module. The control module is connected to the corresponding energy storage inverter. The energy storage battery pack is connected to an external load through the corresponding energy storage inverter. The photovoltaic power generation module is connected to the corresponding energy storage battery pack through the energy storage inverter. The control module performs the following steps to control the energy storage battery pack to charge and discharge: Obtaining the remaining discharge capacity of the energy storage battery group in each of the energy storage subsystems, and controlling the adjustment of the output power of the energy storage inverter corresponding to each energy storage battery group based on the obtained remaining discharge capacity of all the energy storage battery groups and the total remaining discharge capacity of the energy storage system; wherein the total remaining discharge capacity of the energy storage system is the sum of the remaining discharge capacity of all the energy storage battery groups; In each of the energy storage subsystems, the output voltage of the corresponding energy storage inverter is sampled to obtain the output voltage modulus of the energy storage inverter; and the output voltage of the energy storage inverter is compensated based on the output voltage modulus and the output power corresponding to the energy storage inverter.

17. The energy storage system according to claim 16, characterized in that: The step of sampling the output voltage of the corresponding energy storage inverter to obtain the output voltage modulus of the energy storage inverter includes: Obtaining a first preset value and a second preset value of the output voltage based on the output voltage, and obtaining the output voltage modulus based on the first preset value and the second preset value; The output voltage modulus is equal to the square root of the sum of the square of the first preset value and the square of the second preset value.

18. The energy storage system according to claim 16, characterized in that: The step of compensating the output voltage of the energy storage inverter based on the output voltage modulus and the output power corresponding to the energy storage inverter includes: Obtaining a voltage compensation value of the energy storage inverter based on the output power and the output voltage modulus; The output voltage of the energy storage inverter is compensated based on the voltage compensation value.

19. The energy storage system according to claim 16, characterized in that: The step of controlling the output power of the energy storage inverter corresponding to each energy storage battery group based on the obtained remaining discharge power of all the energy storage battery groups and the total remaining discharge power of the energy storage system includes: Obtaining the output power of the energy storage system; Based on the total discharge residual power of the energy storage system and the discharge residual power of each of the energy storage battery groups, obtaining the discharge residual power weight of each of the energy storage battery groups; wherein the discharge residual power of the energy storage battery group is obtained based on the residual power of the energy storage battery group and the preset residual power; Based on the discharge residual power weight of the energy storage battery group and the output power of the energy storage system, the output power of the energy storage inverter corresponding to each energy storage battery group is controlled to be adjusted.

20. The energy storage system according to claim 16, characterized in that: The control method further includes: Obtaining the remaining charge of the energy storage battery group in each of the energy storage subsystems, and based on the remaining charge weight of each energy storage battery group in the total remaining charge of the energy storage system, controlling the adjustment of the output power of the energy storage inverter corresponding to each energy storage battery group, and charging the energy storage battery group; The total remaining charge of the energy storage system is the sum of the remaining charge of all the energy storage battery packs.

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