SOC equalization control method and apparatus for energy storage system

Abstract

Provided are an SOC equalization control method and apparatus for an energy storage system. The energy storage system comprises a battery module, a DC / AC conversion module and a transformer module, wherein the battery module comprises several battery charging and discharging units connected in a cascaded manner; the battery module is connected to the DC / AC conversion module; the DC / AC conversion module is connected to the transformer module; and the transformer module is connected to a power grid. The method comprises: calculating the SOC values of battery charging and discharging units at the beginning of each control period; determining the period type of the control period, wherein the period type comprises a charging control period and a discharging control period; performing group division on the battery charging and discharging units on the basis of the period type and the SOC values, so as to obtain a grouping result; and on the basis of the grouping result, controlling the battery charging and discharging units to access an energy storage system, so as to perform charging or discharging.

Description

Energy storage system SOC balance control method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims the priority of Chinese patent application with application number 2024100287429 and application date January 5, 2024. The entire contents of the Chinese patent application are hereby incorporated into this application by reference. Technical Field

[0003] The present disclosure relates to the technical field of power system energy storage technology, and in particular to a SOC balancing control method and device for an energy storage system. Background Art

[0004] In the field of renewable energy generation, energy sources such as wind and solar power are characterized by intermittent generation and high volatility, which can easily lead to unstable power output. Cascaded battery energy storage systems can effectively solve this problem. They enable controlled storage and release of energy. As the voltage and capacity of energy storage power stations increase, cascaded battery energy storage systems have gained widespread application.

[0005] The battery's state of charge (SOC) is a key parameter describing the battery's current state. It is defined as the ratio of the battery's current remaining capacity to its fully charged capacity. Unbalanced SOC control in cascaded battery energy storage systems can shorten the system's lifespan and reduce its efficiency. Battery lifespan is crucial to the system's future success. Therefore, balanced SOC control is a crucial measure for extending battery life and improving energy storage system utilization, and is a core and essential function of energy storage systems. Summary of the Invention

[0006] The first objective of the present disclosure is to propose a SOC balancing control method for an energy storage system to achieve balanced control of the SOC of each battery in the energy storage system, improve the charging and discharging efficiency of the energy storage system, and extend the service life of the energy storage system.

[0007] The second objective of the present disclosure is to provide an SOC balancing control device for an energy storage system.

[0008] A third objective of the present disclosure is to provide an electronic device.

[0009] A fourth object of the present disclosure is to provide a non-transitory computer-readable storage medium.

[0010] A fifth object of the present disclosure is to provide a computer program product.

[0011] A sixth object of the present disclosure is to provide a computer program.

[0012] To achieve the above objectives, a first embodiment of the present disclosure provides a method for SOC balancing control of an energy storage system. The energy storage system includes a battery module, a DC / AC conversion module, and a transformer module. The battery module includes a plurality of battery charging and discharging units connected in cascade. The battery module is connected to the DC / AC conversion module, the DC / AC conversion module is connected to the transformer module, and the transformer module is connected to a power grid. The method includes:

[0013] At the beginning of each control cycle, calculating the SOC value of each battery charging and discharging unit;

[0014] Determining a cycle type of the control cycle, where the cycle type includes a charge control cycle and a discharge control cycle;

[0015] Dividing the battery charging and discharging units into groups based on the cycle type and the SOC value to obtain a grouping result;

[0016] Based on the grouping result, the battery charging and discharging unit is controlled to connect to the energy storage system for charging or discharging.

[0017] In some embodiments, the grouping of the battery charging and discharging units based on the cycle type and the SOC value to obtain grouping results includes:

[0018] In response to the cycle type being the charging control cycle, obtaining a preset first threshold and a second threshold, and dividing the battery charging and discharging units into groups based on the first threshold and the second threshold to obtain a first grouping result;

[0019] In response to the cycle type being the discharge control cycle, obtaining a preset third threshold and a fourth threshold, and dividing the battery charging and discharging units into groups based on the third threshold and the fourth threshold to obtain a second grouping result;

[0020] The groups include an access system unit group and a bypass unit group.

[0021] In some embodiments, the first threshold is smaller than the second threshold, and the grouping of the battery charging and discharging units based on the first threshold and the second threshold to obtain a first grouping result includes:

[0022] dividing the m battery charging and discharging units whose SOC values ​​are less than the first threshold into the access system unit group;

[0023] The n battery charge and discharge units whose SOC values ​​are greater than or equal to the first threshold and less than the second threshold are divided into the bypass unit group.

[0024] In some embodiments, the third threshold is greater than the fourth threshold, and the grouping of the battery charging and discharging units based on the third threshold and the fourth threshold to obtain a second grouping result includes:

[0025] dividing the m battery charging and discharging units whose SOC values ​​are greater than the third threshold into the access system unit group;

[0026] The n battery charge and discharge units whose SOC values ​​are less than or equal to the third threshold and greater than the fourth threshold are divided into the bypass unit group.

[0027] In some embodiments, controlling the battery charging and discharging unit to connect to the energy storage system for charging or discharging based on the grouping result includes:

[0028] Connecting the m battery charging and discharging units in the access system unit group to the energy storage system for charging or discharging;

[0029] The n battery charging and discharging units in the bypass unit group are placed in a bypass state through a charging and discharging switch.

[0030] In some embodiments, the value range of m is:

[0031] Among them, d min Indicates the minimum available duty cycle of the battery charge and discharge unit, d max Indicates the maximum available duty cycle of the battery charge and discharge unit, U cell-max Indicates the maximum allowable voltage value of the battery charging and discharging unit, U cell-min Indicates the minimum allowable voltage value of the battery charging and discharging unit, U dc Indicates the DC bus voltage value at the output end of the battery module. m is an integer value.

[0032] In some embodiments, the method further comprises:

[0033] Based on the number of the battery charge and discharge units connected to the energy storage system and the SOC value of each of the battery charge and discharge units, a modulation voltage of the battery charge and discharge units connected to the energy storage system is obtained.

[0034] In some embodiments, obtaining the modulation voltage of the battery charge and discharge unit connected to the energy storage system based on the number of the battery charge and discharge units connected to the energy storage system and the SOC value of each of the battery charge and discharge units includes:

[0035] Determining an average SOC value based on the SOC value of each of the battery charging and discharging units connected to the energy storage system;

[0036] Based on the number of the battery charge and discharge units connected to the energy storage system and the average SOC value, a modulation voltage of the battery charge and discharge units included in the energy storage system is calculated.

[0037] In some embodiments, the modulation voltage is calculated as follows:

[0038] Modulation voltage

[0039] Among them, u i is the modulation voltage of the i-th battery charge and discharge unit, SOC i is the SOC value of the i-th battery charging and discharging unit, is the average SOC value of all battery charging and discharging units connected to the energy storage system, m is the number of battery charging and discharging units connected to the energy storage system in the current control cycle, s represents the charging or discharging state, s is positive when it represents charging, and s is negative when it represents discharging, u m Indicates the total modulation voltage of the battery module.

[0040] To achieve the above objectives, a second embodiment of the present disclosure provides an energy storage system SOC balancing control device, the energy storage system comprising a battery module, a DC / AC conversion module, and a transformer module. The battery module comprises a plurality of cascade-connected battery charging and discharging units, the battery module being connected to the DC / AC conversion module, the DC / AC conversion module being connected to the transformer module, and the transformer module being connected to a power grid. The device comprises an SOC value calculation module, a cycle determination module, a battery charging and discharging unit grouping module, and a charging and discharging control module.

[0041] The SOC value calculation module is used to calculate the SOC value of each battery charging and discharging unit at the beginning of each control cycle;

[0042] The cycle determination module is used to determine the cycle type of the control cycle, and the cycle type includes a charging control cycle and a discharging control cycle;

[0043] The battery charge and discharge unit grouping module is used to group the battery charge and discharge units based on the cycle type and the SOC value to obtain a grouping result;

[0044] The charge and discharge control module is used to control the battery charge and discharge unit to connect to the energy storage system for charging or discharging based on the grouping result.

[0045] To achieve the above-mentioned objectives, the third embodiment of the present disclosure proposes an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the energy storage system SOC balancing control method proposed in the first embodiment of the present disclosure is implemented.

[0046] To achieve the above-mentioned purpose, the fourth embodiment of the present disclosure proposes a non-temporary computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the energy storage system SOC balancing control method proposed in the first embodiment of the present disclosure is implemented.

[0047] To achieve the above-mentioned purpose, the fifth embodiment of the present disclosure proposes a computer program product. When the instruction processor in the computer program product is executed, the energy storage system SOC balancing control method proposed in the first embodiment of the present disclosure is executed.

[0048] To achieve the above-mentioned purpose, the sixth embodiment of the present disclosure proposes a computer program, which includes computer program code. When the computer program code is run on a computer, the computer executes the energy storage system SOC balancing control method proposed in the first embodiment of the present disclosure.

[0049] The present disclosure provides a method and device for SOC balancing control of an energy storage system. The method groups battery charge and discharge units in a battery module of the energy storage system according to their SOC values, and controls the battery charge and discharge units connected to the energy storage system based on the grouping results. Furthermore, the method modulates the distribution of voltages to each battery charge and discharge unit connected to the energy storage system according to its respective SOC value, thereby achieving balanced control of each battery charge and discharge unit in the energy storage system, improving the charge and discharge efficiency of the battery modules of the energy storage system, extending the service life of the battery charge and discharge units, and enhancing the reliability of the operation of the energy storage system.

[0050] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The above and / or additional aspects and advantages of the present disclosure will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0052] FIG1 is a schematic diagram of the circuit structure of an energy storage system in a SOC balancing control method of an energy storage system according to an embodiment of the present disclosure.

[0053] FIG2 is a schematic diagram of the circuit structure of a battery module in a SOC balancing control method for an energy storage system according to an embodiment of the present disclosure.

[0054] FIG3 is a flow chart of a method for SOC balancing control of an energy storage system according to an embodiment of the present disclosure.

[0055] FIG4 is a flow chart of steps S201 - S202 in a method for SOC balancing control of an energy storage system according to an embodiment of the present disclosure.

[0056] FIG5 is a module diagram of an SOC balancing control device for an energy storage system according to an embodiment of the present disclosure.

[0057] Description of the accompanying symbols: 1. SOC value calculation module; 2. Cycle judgment module; 3. Battery charging and discharging unit grouping module; 4. Charging and discharging control module. DETAILED DESCRIPTION

[0058] The following describes in detail embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0059] A method and device for SOC balancing control of an energy storage system according to an embodiment of the present disclosure will be described below with reference to the accompanying drawings.

[0060] Figure 1 shows a schematic diagram of the circuit structure of an energy storage system applied in an embodiment of the present disclosure. As shown in Figure 1, the energy storage system includes a battery module, a DC / AC conversion module and a transformer module. The battery module includes a plurality of battery charging and discharging units connected in cascade. The battery module is connected to the DC / AC conversion module, the DC / AC conversion module is connected to the transformer module, and the transformer module is connected to the power grid.

[0061] FIG2 shows a schematic diagram of the circuit structure of the battery module in the embodiment of the present disclosure. In the battery module, each battery charge and discharge unit includes a battery cell, an energy storage capacitor, and an H-bridge converter topology composed of switch tubes S1, S2, S3, and S4. In the embodiment of the present disclosure, an H-bridge converter topology is used as an example for illustration. Converter topologies such as a half-bridge topology and a full-bridge topology may also be used, which are not limited here. Among them, the battery cell can be connected to the converter through a controllable charge and discharge switch, or the battery charge and discharge unit can be connected to the energy storage system through a controllable charge and discharge switch. In the embodiment of the present disclosure, connecting the battery charge and discharge unit to the energy storage system through the charge and discharge switch can be regarded as the battery charge and discharge unit being connected to the energy storage system for charging or discharging; if the charge and discharge switch is disconnected, it is regarded as bypassing the corresponding battery charge and discharge unit.

[0062] FIG3 is a flow chart of a method for SOC balancing control of an energy storage system according to an embodiment of the present disclosure. As shown in FIG3 , the method includes the following steps:

[0063] S101. At the beginning of each control cycle, calculate the SOC value of each battery charging and discharging unit;

[0064] S102, determining a cycle type of a control cycle, where the cycle type includes a charging control cycle and a discharging control cycle;

[0065] S103, dividing the battery charging and discharging units into groups based on the cycle type and the SOC value to obtain a grouping result;

[0066] S104: Based on the grouping result, control the battery charging and discharging unit to connect to the energy storage system for charging or discharging.

[0067] Among them, step S101, at the beginning of each control cycle, calculates the SOC value of each battery charge and discharge unit. In the embodiment of the present disclosure, the control cycle refers to the charging control cycle or the discharging control cycle of the energy storage system. At the beginning of each predetermined control cycle, the relevant parameters of the battery charge and discharge unit are collected, and the SOC value of the battery body in each battery charge and discharge unit is calculated. The calculation method commonly used in the field of SOC value can be used, such as voltage method, discharge test method and ampere-hour measurement method, etc. The calculated SOC values ​​are recorded as SOC1, SOC2, ..., SOC N And sort the SOC values ​​according to size.

[0068] Step S102: Determine the cycle type of the control cycle. In the embodiment of the present disclosure, the current of the energy storage system can be collected and the direction of the current can be used to determine whether it is a charging control cycle or a discharging control cycle.

[0069] Step S103 divides the battery charging and discharging units into groups based on the cycle type and SOC value, obtaining grouping results. In the disclosed embodiment, the battery charging and discharging unit groups include a system-connected unit group and a bypass unit group. The system-connected unit group is a unit group that is ready to be connected to the energy storage system for charging and discharging, and the bypass unit group is a standby unit group that is temporarily not connected to the energy storage system.

[0070] Specifically, the grouping of battery charging and discharging units needs to be carried out according to different cycle types. The embodiment of the present disclosure sets different division schemes for different control cycles, wherein a first threshold and a second threshold are set for the charging control cycle, so as to divide the battery charging and discharging units into groups based on the first threshold and the second threshold, and obtain a first grouping result; a third threshold and a fourth threshold are set for the discharging control cycle, so as to divide the battery charging and discharging units into groups based on the third threshold and the fourth threshold, and obtain a second grouping result.

[0071] Among them, the first threshold, the second threshold, the third threshold, and the fourth threshold are set according to the charging and discharging needs of the energy storage system, and the first threshold is less than the second threshold, the third threshold is greater than the fourth threshold, the second threshold can be 100%, and the fourth threshold can be 0.

[0072] More specifically, if the cycle type of the current control cycle is a charging control cycle, m battery charge and discharge units with SOC values ​​less than a first threshold among all current battery charge and discharge units are divided into the access system unit group, and n battery charge and discharge units with SOC values ​​greater than or equal to the first threshold and less than a second threshold are divided into the bypass unit group.

[0073] More specifically, if the cycle type of the current control cycle is a discharge control cycle, m battery charge and discharge units whose SOC values ​​are greater than the third threshold among all current battery charge and discharge units are divided into the access system unit group, and n battery charge and discharge units whose SOC values ​​are less than or equal to the first threshold and greater than the fourth threshold are divided into the bypass unit group.

[0074] Specifically, in order to further improve the conversion efficiency, the number of battery charging and discharging units connected to the energy storage system is limited by the duty cycle of the battery charging and discharging units and the terminal voltage of the battery cells. In the embodiment of the present disclosure, the value range of m is set to:

[0075] Among them, d min Indicates the minimum available duty cycle of the battery charge and discharge unit, d max Indicates the maximum available duty cycle of the battery charge and discharge unit, U cell-max Indicates the maximum allowable voltage value of the battery charging and discharging unit, U cell-min Indicates the minimum allowable voltage value of the battery charging and discharging unit, U dc Indicates the DC bus voltage value at the output end of the battery module. m is an integer value.

[0076] Step S104: Based on the grouping results, the battery charge and discharge units are controlled to connect to the energy storage system for charging or discharging. After determining the access system unit group and the bypass unit group, the m battery charge and discharge units in the access system unit group are connected to the energy storage system for charging or discharging, and the n battery charge and discharge units in the bypass unit group are placed in a bypass state using the charge and discharge switches.

[0077] While the SOC of the energy storage system is controlled according to the above embodiment, the SOC of the battery cells in the battery charging and discharging units connected to the energy storage system still vary. Therefore, it is necessary to determine the DC side battery current based on the difference between the SOC value of each battery charging and discharging unit and the average value, thereby further achieving balanced SOC control.

[0078] In another embodiment of the present disclosure, the above method further includes: obtaining the modulation voltage of the battery charge and discharge unit connected to the energy storage system based on the number of the battery charge and discharge units connected to the energy storage system and the SOC value of each of the battery charge and discharge units.

[0079] When the battery capacity is a constant, the change in the battery cell within a predetermined time is proportional to the current. Therefore, the modulation voltage of each cell can be distributed according to the difference between the SOC value of each battery charging and discharging unit connected to the energy storage system and the average value to achieve switching control of each battery charging and discharging unit.

[0080] Specifically, referring to FIG4 , the method of obtaining the modulation voltage of the battery charge and discharge unit connected to the energy storage system based on the number of the battery charge and discharge units connected to the energy storage system and the SOC value of each of the battery charge and discharge units specifically includes the following steps:

[0081] S201, determining an average SOC value based on the SOC value of each battery charging and discharging unit connected to the energy storage system;

[0082] S202: Calculate a modulation voltage of the battery charging and discharging unit in the energy storage system based on the number of the battery charging and discharging units connected to the energy storage system and the average SOC value.

[0083] The calculation formula for setting the modulation voltage in the embodiment of the present disclosure is as follows:

[0084] Modulation voltage

[0085] Among them, u i is the modulation voltage of the i-th battery charge and discharge unit, SOC i is the SOC value of the i-th battery charging and discharging unit, is the average SOC value of all battery charging and discharging units connected to the energy storage system, m is the number of battery charging and discharging units connected to the energy storage system in the current control cycle, s represents the charging or discharging state, s is positive when it represents charging, and s is negative when it represents discharging, u m Indicates the total modulation voltage of the battery module.

[0086] In summary, the technical solution provided by the embodiments of the present disclosure groups the battery charge and discharge units in the battery modules of the energy storage system according to their SOC values, and controls the battery charge and discharge units connected to the energy storage system based on the grouping results. Furthermore, for each battery charge and discharge unit connected to the energy storage system, the modulation voltage is distributed according to its respective SOC value, thereby achieving balanced control of each battery charge and discharge unit in the energy storage system, improving the charge and discharge efficiency of the battery modules of the energy storage system, extending the service life of the battery charge and discharge units, and improving the reliability of the operation of the energy storage system.

[0087] In order to implement the above embodiments, the present disclosure also proposes an SOC balancing control device for an energy storage system.

[0088] FIG5 is a schematic structural diagram of an energy storage system SOC balancing control device provided by an embodiment of the present disclosure.

[0089] As shown in Figure 5, the device includes an SOC value calculation module, a cycle judgment module, a battery charge and discharge unit grouping module and a charge and discharge control module; the SOC value calculation module is used to calculate the SOC value of each battery charge and discharge unit at the beginning of each control cycle; the cycle judgment module is used to determine the cycle type of the control cycle, which includes a charging control cycle and a discharging control cycle; the battery charge and discharge unit grouping module is used to group the battery charge and discharge units based on the cycle type and SOC value to obtain a grouping result; the charge and discharge control module is used to control the battery charge and discharge units to connect to the energy storage system for charging or discharging based on the grouping result.

[0090] In order to implement the above embodiments, the present disclosure further proposes an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the energy storage system SOC balancing control method proposed in the above embodiments of the present disclosure is implemented.

[0091] In order to implement the above embodiments, the present disclosure further proposes a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the energy storage system SOC balancing control method proposed in the above embodiments of the present disclosure.

[0092] In order to implement the above embodiments, the present disclosure further proposes a computer program product. When an instruction processor in the computer program product is executed, the energy storage system SOC balancing control method proposed in the above embodiments of the present disclosure is executed.

[0093] In order to implement the above embodiments, the present disclosure further proposes a computer program, which includes computer program code. When the computer program code runs on a computer, it enables the computer to execute the energy storage system SOC balancing control method proposed in the above embodiments of the present disclosure.

[0094] It should be noted that the above explanation of the embodiment of the energy storage system SOC balancing control method is also applicable to the energy storage system SOC balancing control device, electronic device, non-temporary computer-readable storage medium, computer program product and computer program of the embodiment of the present disclosure, and will not be repeated here.

[0095] The collection, storage, use, processing, transmission, provision and disclosure of user personal information involved in this disclosure are in compliance with relevant laws and regulations and do not violate public order and good morals.

[0096] It is important to note that personal information collected from users should be used for legitimate and reasonable purposes and should not be shared or sold beyond these legitimate uses. Furthermore, such collection / sharing should be conducted only after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign an agreement / authorization that includes the relevant user information before using the feature. Furthermore, any necessary steps must be taken to safeguard and secure access to such personal information and ensure that others with access to personal information comply with its privacy policy and procedures.

[0097] This disclosure contemplates providing implementations that allow users to selectively block the use or access of personal information data. Specifically, this disclosure contemplates providing hardware and / or software to prevent or block access to such personal information data. Risks can be minimized by limiting data collection and deleting data once it is no longer needed. Furthermore, where applicable, such personal information can be de-identified to protect user privacy.

[0098] In the descriptions of the aforementioned embodiments, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are mutually inconsistent.

[0099] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0100] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present disclosure includes additional implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present disclosure belong.

[0101] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0102] It should be understood that various parts of the present disclosure can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0103] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0104] In addition, the functional units in the various embodiments of the present disclosure may be integrated into a single processing module, or each unit may exist physically separately, or two or more units may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or in the form of software functional modules. If the integrated modules are implemented in the form of software functional modules and sold or used as independent products, they may also be stored in a computer-readable storage medium.

[0105] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. A person of ordinary skill in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A method for SOC balancing control of an energy storage system, wherein, The energy storage system includes a battery module, a DC / AC conversion module, and a transformer module. The battery module includes a plurality of cascaded battery charge and discharge units. The battery module is connected to the DC / AC conversion module, the DC / AC conversion module is connected to the transformer module, and the transformer module is connected to the power grid. The method includes: At the beginning of each control period, calculate the SOC value of each of the battery charge and discharge units; Determine the period type of the control period, where the period type includes a charging control period and a discharging control period; Based on the period type and the SOC value, group the battery charge and discharge units to obtain a grouping result; Control the battery charge and discharge units to access the energy storage system for charging or discharging based on the grouping result.

2. The SOC balancing control method for the energy storage system according to claim 1, wherein, The grouping the battery charge and discharge units based on the period type and the SOC value to obtain a grouping result includes: In response to the period type being the charging control period, obtain a preset first threshold and a second threshold, and group the battery charge and discharge units based on the first threshold and the second threshold to obtain a first grouping result; In response to the period type being the discharging control period, obtain a preset third threshold and a fourth threshold, and group the battery charge and discharge units based on the third threshold and the fourth threshold to obtain a second grouping result; Wherein, the groups include an access system unit group and a bypass unit group.

3. The SOC balancing control method for the energy storage system according to claim 2, wherein, The first threshold is less than the second threshold. The grouping the battery charge and discharge units based on the first threshold and the second threshold to obtain a first grouping result includes: Group m of the battery charge and discharge units with an SOC value less than the first threshold into the access system unit group; Group n of the battery charge and discharge units with an SOC value greater than or equal to the first threshold and less than the second threshold into the bypass unit group.

4. The SOC equalization control method for the energy storage system according to claim 2, wherein, The third threshold is greater than the fourth threshold. The grouping the battery charge and discharge units based on the third threshold and the fourth threshold to obtain a second grouping result includes: Group m of the battery charge and discharge units with an SOC value greater than the third threshold into the access system unit group; Group n of the battery charge and discharge units with an SOC value less than or equal to the third threshold and greater than the fourth threshold into the bypass unit group.

5. The SOC balancing control method for the energy storage system according to claim 3 or 4, wherein The controlling the battery charge and discharge units to access the energy storage system for charging or discharging based on the grouping result includes: Connect m of the battery charge and discharge units in the access system unit group to the energy storage system for charging or discharging; Place n of the battery charge and discharge units in the bypass unit group in a bypass state through a charge and discharge switch.

6. The SOC balancing control method for the energy storage system according to claim 5, wherein The value range of m is as follows: Among them, d min represents the minimum available duty cycle of the battery charge and discharge unit, d max represents the maximum available duty cycle of the battery charge and discharge unit, U cell-max represents the maximum allowable voltage value of the battery charge and discharge unit, U cell-min represents the minimum allowable voltage value of the battery charge and discharge unit, U dc represents the DC bus voltage value at the output end of the battery module, and m takes an integer value.

7. The method for SOC balancing control of the energy storage system according to any one of claims 1 to 6 further includes: Based on the number of the battery charge and discharge units connected to the energy storage system and the SOC value of each of the battery charge and discharge units, obtain the modulation voltage of the battery charge and discharge units connected to the energy storage system.

8. The SOC equalization control method for the energy storage system according to claim 7, wherein, Obtaining the modulation voltage of the battery charge and discharge units connected to the energy storage system based on the number of the battery charge and discharge units connected to the energy storage system and the SOC value of each of the battery charge and discharge units includes: Determining the average SOC value based on the SOC value of each of the battery charge and discharge units connected to the energy storage system Calculating the modulation voltage of the battery charge and discharge units included in the energy storage system based on the number of the battery charge and discharge units connected to the energy storage system and the average SOC value.

9. The SOC equalization control method for the energy storage system according to claim 8, wherein, The calculation formula of the modulation voltage is as follows: where u i is the modulation voltage of the i-th battery charge and discharge unit, and SOC i is the SOC value of the i-th battery charge and discharge unit, is the average SOC value of all battery charge and discharge units in the energy storage system, m is the number of battery charge and discharge units connected to the energy storage system in the current control period, s represents the charge or discharge state, s is positive for charging and s is negative for discharging, u m represents the total modulation voltage of the battery module.

10. An SOC balancing control device for an energy storage system, wherein, The energy storage system includes a battery module, a DC / AC conversion module, and a transformer module. The battery module includes a plurality of cascaded battery charge and discharge units. The battery module is connected to the DC / AC conversion module. The DC / AC conversion module is connected to the transformer module. The transformer module is connected to the power grid. The device includes an SOC value calculation module, a period determination module, a battery charge and discharge unit grouping module, and a charge and discharge control module; The SOC value calculation module is configured to calculate the SOC value of each of the battery charge and discharge units at the start of each control period; The period determination module is configured to determine the period type of the control period, and the period type includes a charge control period and a discharge control period; The battery charge and discharge unit grouping module is configured to group the battery charge and discharge units based on the period type and the SOC value to obtain a grouping result; The charge and discharge control module is configured to control the battery charge and discharge units to be connected to the energy storage system for charging or discharging based on the grouping result.

11. An electronic device, comprising: At least one processor; And A memory communicatively connected to the at least one processor; wherein, The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the energy storage system SOC balancing control method according to any one of claims 1-9.

12. A non-transitory computer-readable storage medium storing computer instructions, wherein, The computer instructions are used to cause the computer to execute the energy storage system SOC balancing control method according to any one of claims 1-9.

13. A computer program product, comprising a computer program, where the computer program, when executed by a processor, implements the energy storage system SOC balancing control method according to any one of claims 1-9.

14. A computer program, the computer program comprising computer program code, where when the computer program code runs on a computer, it causes the computer to execute the energy storage system SOC balancing control method according to any one of claims 1-9.

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