Energy storage system, and control method and apparatus therefor

Abstract

The present application provides an energy storage system, and a control method and apparatus therefor. In the control method for the energy storage system, for the energy storage system comprising a plurality of first sub-modules, when a second sub-module is configured into the energy storage system, the battery normalization scoring parameter of the second sub-module is acquired, and then on the basis of a preset score limit value, the second sub-module is controlled to be maintained at a configured state or the second sub-module is removed. The second sub-module is controlled on the basis of fully considering the battery capacity of the second sub-module, thereby achieving coordinated control for different sub-modules, fully testing the performance of a novel sub-module, and being conducive to the overall stable response of the system.

Description

Energy storage system and control method and device thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application 202311459943.6, filed on November 3, 2023, entitled “A storage system and its control method and device,” and the entire contents of that application are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of energy storage technology, and more specifically, to an energy storage system and a control method and device thereof. Background Art

[0004] Energy storage technology is widely used because it can improve the utilization rate of renewable energy generation, smooth active power fluctuations, and help shift peaks and valleys in power systems. Direct-mounted energy storage power conversion systems, with their modular structure and high safety, have attracted widespread attention in high-voltage, high-capacity applications. The quality of their control strategies directly impacts the performance and reliability of energy storage systems.

[0005] In actual projects, before putting an energy storage valve composed of new sub-modules into use, a single new sub-module will be added to the existing energy storage valve for performance testing. At this time, the energy storage system is composed of different types of sub-modules. The current control method mainly adopts the original control strategy for the existing sub-modules to control the new sub-module. However, the new sub-modules often differ from the existing sub-modules in capacity, voltage level, etc. Therefore, this control method cannot fully test the performance of the new sub-module, and is also not conducive to the stable response of the entire system.

[0006] Summary of the Invention

[0007] In view of the above problems, the present application provides an energy storage system and its control method and device to solve the problem that the control method in the related art cannot fully test the performance of the new sub-module, and is also not conducive to the stable response of the entire system.

[0008] In a first aspect, the present application provides a control method for an energy storage system, wherein the energy storage system includes several first submodules; the method includes: when a second submodule including a battery cell is added to the energy storage system, obtaining a battery normalization scoring parameter of the second submodule; the battery normalization scoring parameter is a comprehensive scoring value characterizing the battery operating performance; based on the battery normalization scoring parameter and a preset scoring limit, controlling the second submodule to remain in an engaged state or to remove the second submodule.

[0009] In the above implementation, for an energy storage system including several first submodules, when a second submodule is activated, the normalized battery scoring parameters of the second submodule are obtained. Then, based on preset scoring limits, the second submodule is controlled to maintain its activation or be deactivated. Control of the second submodule is achieved by fully considering its battery capacity, thereby achieving coordinated control of different submodules. This allows for thorough testing of the performance of new submodules, facilitating a stable response for the entire system.

[0010] In some embodiments, the first submodule and the second submodule are energy storage submodules with different terminal voltages and different capacities.

[0011] In the above implementation process, an optional type of the second submodule is provided, that is, a submodule that is different from the original energy storage submodule in the energy storage system in terms of terminal voltage and capacity.

[0012] In some embodiments, the battery normalization score parameter is calculated based on at least two indicators of battery state of charge, battery health, battery current inconsistency, and battery power capability, and a weight corresponding to each of the at least two indicators.

[0013] In the above implementation process, a specific method for calculating the normalized battery scoring parameters is provided.

[0014] In some embodiments, controlling the second submodule to remain in the engaged state or to remove the second submodule based on the battery normalization score parameter and the preset score limit includes: controlling the second submodule to remain in the engaged state when the battery normalization score parameter is greater than the preset score limit; and removing the second submodule when the battery normalization score parameter is not greater than the preset score limit.

[0015] In the above implementation process, a specific control strategy for the new submodule is provided, namely, a maximum available control strategy. Through this strategy, the new submodule can be maximized and put into use as much as possible to support the bus voltage.

[0016] In some embodiments, controlling the second submodule to remain in the engaged state or to remove the second submodule according to the battery normalization score parameter and the preset score limit includes: when the battery normalization score parameter is greater than the preset score limit, controlling the second submodule to remain in the engaged state or to remove the second submodule at a set frequency.

[0017] In the above implementation process, another specific control strategy for the new sub-module is provided, namely the fixed frequency control strategy. Through this strategy, the new sub-module is put into operation and cut off according to the set frequency, thereby better meeting the operation requirements of the actual energy storage valve project.

[0018] In some embodiments, the method further includes: obtaining dynamic performance of the second submodule at different frequencies and a response of the energy storage system.

[0019] In the above implementation process, under the fixed frequency control strategy, the new sub-module will be put into operation and removed at a specific frequency. Therefore, the dynamic performance of the new sub-module at various frequencies can be fully tested. At the same time, the response of the system when the new sub-module is put into operation and removed at different frequencies can also be tested, thereby providing convenient conditions for the improvement of the energy storage system.

[0020] In some embodiments, controlling the second submodule to remain in the on-state or to remove the second submodule based on the battery normalization score parameter and a preset score limit includes: executing a charging strategy when an initial charging current of the second submodule is greater than a charging threshold; under the charging strategy, if the real-time charging current is not greater than the charging threshold, removing the second submodule; if the real-time charging current is greater than the charging threshold, executing a discharging strategy when the battery normalization score parameter is less than or equal to the preset score limit; and controlling the second submodule to remain in the on-state when the battery normalization score parameter is greater than the preset score limit; executing a discharging strategy when the initial discharge current of the second submodule is greater than the discharge threshold; under the discharge strategy, if the real-time discharge current is not greater than the discharge threshold, removing the second submodule; if the real-time discharge current is greater than the discharge threshold, executing a charging strategy when the battery normalization score parameter is less than or equal to the preset score limit; and controlling the second submodule to remain in the on-state when the battery normalization score parameter is greater than the preset score limit.

[0021] In the above implementation process, another specific control strategy is provided for the new sub-module, namely the SOX full-operating condition control strategy. Through this strategy, the new sub-module can operate in the full scoring section of SOX, providing further convenient conditions for testing the battery performance of the new sub-module.

[0022] In some embodiments, the method further includes: after controlling the second submodule to remain in an on-state, calculating the required number of the first submodule to be put into operation according to the real-time voltage of the second submodule and the average value of the capacitor voltage of the first submodule.

[0023] In the above implementation process, when a new sub-module is put into use, the number of existing sub-modules to be put into use is calculated based on the real-time voltage of the new sub-module and the average capacitor voltage of the existing sub-modules, so as to control the switching of the existing sub-modules, thereby minimizing the voltage fluctuation caused by switching the new sub-module with a larger port voltage.

[0024] In some embodiments, the calculation of the required number of inputs of the first submodule based on the real-time voltage of the second submodule and the average value of the capacitor voltage of the first submodule includes: dividing the difference obtained by subtracting the real-time voltage of the second submodule from the DC voltage modulation wave by the average value of the capacitor voltage of the first submodule to obtain the required number of inputs of the first submodule.

[0025] In the above implementation process, a specific method is provided for calculating the number of existing sub-modules that should be put into use when a new sub-module is put into use.

[0026] In a second aspect, the present application provides a control device for an energy storage system, wherein the energy storage system includes several first submodules; the device includes: an acquisition module for acquiring a battery normalization scoring parameter of the second submodule when a second submodule including a battery cell is added to the energy storage system; the battery normalization scoring parameter is a comprehensive scoring value characterizing the battery operating performance; and a control module for controlling the second submodule to remain in an engaged state or to remove the second submodule based on the battery normalization scoring parameter and a preset scoring limit.

[0027] In a third aspect, the present application provides an electronic device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the method described in any one of the first aspects are implemented.

[0028] In a fourth aspect, the present application provides an energy storage system, comprising an energy storage unit and a control unit; the control unit adopts the electronic device as described in the third aspect.

[0029] In a fifth aspect, the present application provides a computer-readable storage medium having instructions stored thereon. When the instructions are executed on a computer, the computer is caused to execute the method as described in any one of the first aspects.

[0030] In a sixth aspect, the present application provides a computer program product, which, when running on a computer, enables the computer to execute the method as described in any one of the first aspects.

[0031] Other features and advantages disclosed in the present application will be described in the following description, or some features and advantages can be inferred or determined without doubt from the description, or can be learned by implementing the above-mentioned technology disclosed in the present application.

[0032] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0034] FIG1 is a schematic diagram of adding a single new submodule to an existing DC energy storage valve test according to some embodiments of the present application;

[0035] FIG2 is a flow chart of a method for controlling an energy storage system provided in some embodiments of the present application;

[0036] FIG3 is a schematic diagram of a process for maximizing available control strategies provided in some embodiments of the present application;

[0037] FIG4 is a schematic diagram of a process of a fixed frequency control strategy provided in some embodiments of the present application;

[0038] FIG5 is a schematic diagram of a process of a SOX full-operating-condition control strategy provided by some embodiments of the present application;

[0039]

[0040] FIG6 is a block diagram of a control device for an energy storage system provided in some embodiments of the present application;

[0041] FIG7 is a structural block diagram of an electronic device provided in some embodiments of the present application. DETAILED DESCRIPTION

[0042] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0044] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0045] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present 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.

[0046] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0047] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0048] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0049] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0050] Currently, direct-mounted energy storage power variation systems have received widespread attention in high-voltage and large-capacity applications. In actual projects, before putting into operation an energy storage valve composed of new submodules, a single new submodule will be added to the existing energy storage valve for performance testing, as shown in Figure 1. Figure 1 is a schematic diagram of a test of a single new submodule added to an existing DC energy storage valve. The DC energy storage valve includes several existing submodules 11. After the new submodule 12 is put into operation, the energy storage system is composed of different types of submodules. The current control method mainly uses the original control strategy for the existing submodule to control the new submodule. However, the new submodule and the existing submodule often have differences in capacity, voltage level, etc. Therefore, this control method cannot fully test the performance of the new submodule, and is also not conducive to the overall stable response of the system.

[0051] To address the above technical issues, an embodiment of the present application provides a control method for an energy storage system. When a second submodule is deployed in the energy storage system, the method obtains the normalized battery scoring parameters of the second submodule and then controls the switching of the second submodule based on preset scoring limits. By adding a control strategy for the second submodule, coordinated control of different submodules is achieved, enabling comprehensive testing of the performance of the new submodule and facilitating a stable response for the entire system.

[0052] Next, the embodiments of the present application are introduced:

[0053] As shown in Figure 2, Figure 2 is a flow chart of a control method for an energy storage system provided in an embodiment of the present application. The energy storage system here can have an energy storage structure based on a DC direct-connect topology. The energy storage system includes a plurality of first submodules, which can be half-bridge energy storage submodules or full-bridge energy storage submodules.

[0054] The method comprises:

[0055] Step 201: When a second submodule including a battery cell is added to the energy storage system, obtain a battery normalization scoring parameter of the second submodule; the battery normalization scoring parameter is a comprehensive scoring value representing the battery operating performance;

[0056] The second submodule mentioned in this step is an energy storage submodule including a battery cell. Each energy storage submodule can include a power module portion consisting of a half-bridge or full-bridge structured power electronic device, a module grading capacitor, and a grading resistor, a battery starting resistance circuit portion, a battery module (consisting of several battery cells), and a bypass switch. In some embodiments, the first submodule and the second submodule are energy storage submodules with different local terminal voltages and different capacities. In other words, the second submodule can be an energy storage submodule that is different from the original first submodule in the energy storage system in terms of terminal voltage and capacity. It can be considered a new submodule, and accordingly, the first submodule can also be called an existing submodule. Optionally, the terminal voltage of the second submodule is higher than the terminal voltage of the first submodule; the capacity of the second submodule is greater than the capacity of the first submodule. In other words, the second submodule has a higher nominal port voltage and a larger battery capacity than the first submodule. Therefore, the second submodule can be a submodule suitable for higher voltage level projects, which can promote the development of energy storage systems towards high voltage and large capacity.

[0057] In addition, in actual applications, when a certain energy storage submodule in the energy storage system fails and is then repaired and re-added to the energy storage system, if there are differences in terminal voltage, capacity, etc. between the energy storage submodule and other submodules in the energy storage system, then the energy storage submodule can also be considered as the second submodule, and the other submodules in the energy storage system are the first submodules.

[0058] In this embodiment, when the second submodule is added to the energy storage system, the battery normalization score parameter of the second submodule can be obtained to control the switching of the second submodule. The battery normalization score parameter, which can be denoted as SOX, is a comprehensive score value that characterizes the battery's operating performance. In other words, the higher the SOX value of the second submodule, the more suitable the second submodule is for deployment. In some embodiments, the battery normalization score parameter can be calculated based on at least two indicators of battery state of charge, battery health, battery current inconsistency, and battery power capability, as well as the weight corresponding to each of the at least two indicators. These indicators are all important indicators that affect battery performance, and they can all be calculated through corresponding algorithms or models. For example, the battery state of charge (SOC) can be calculated based on the ampere-hour integration method or the Kalman filter algorithm; the battery health (SOH) can be calculated by the SOH estimation model, which generally calculates the battery internal resistance based on the current and voltage, and then evaluates the current battery health status based on the internal resistance of the corresponding state; the battery current inconsistency can be obtained by dividing the difference between the maximum current and the minimum current by the average current; the battery power capacity is affected by the battery temperature and the battery current, and there is a corresponding relationship. Therefore, a calculation model that characterizes the corresponding relationship between the battery power capacity and the battery temperature and the battery current can be established through testing. When implemented, the calculation model is used to calculate the battery power capacity of the second submodule based on the real-time battery temperature and the real-time battery current. The weight corresponding to each indicator can be determined according to the importance of each indicator in the high-voltage, large-capacity energy storage system. Of course, in other embodiments, the battery normalization scoring parameter can also be calculated based on other indicators, such as battery voltage, battery temperature, etc.

[0059] Step 202: Control the second submodule to remain in the active state or to remove the second submodule according to the battery normalization score parameter and a preset score limit.

[0060] The preset score limit mentioned in this step can be a pre-set SOX lower limit value, which can be set by testing the response fluctuation of the energy storage system after putting submodules with different SOX values ​​into the energy storage system in the experiment, and combining it with the needs of the specific scenario. When the battery normalization score parameter of any submodule, that is, the SOX value, drops to the SOX lower limit value, it indicates that the submodule is not suitable for being put into the energy storage system. Therefore, according to the battery normalization score parameter of the second submodule and the preset score limit value, the second submodule is controlled to remain in the put-in state or to be cut off, so as to realize the control of the second submodule on the basis of fully considering the battery capacity of the second submodule, while for the control of the first submodule, the original control strategy can still be maintained, so as to realize coordinated control of different submodules.

[0061] In view of the different performance test requirements of the new sub-modules, the control strategy of the new sub-modules can be further subdivided as follows:

[0062] In some embodiments, this step may include: controlling the second submodule to remain in operation when the battery normalization score parameter is greater than a preset score limit; and removing the second submodule when the battery normalization score parameter is not greater than the preset score limit. This is a control strategy for maximizing available control. When the SOX value of the new submodule is greater than the SOX lower limit, the new submodule is kept in operation. Conversely, when the SOX value of the new submodule is less than or equal to the SOX lower limit, the new submodule is removed. This maximizes the utilization of the new submodule, allowing it to be put into operation as much as possible to support the bus voltage. Furthermore, in this strategy, the new submodule is put into operation for a long time, allowing its charge and discharge performance to be fully tested.

[0063] In some embodiments, this step may include: when the battery normalization score parameter does not exceed the preset score limit, controlling the second submodule to remain in the on-state or cutting off the second submodule at a set frequency. This is a control strategy for implementing fixed frequency control. When the SOX of the new submodule is greater than the SOX lower limit, the power electronic switching device of the new submodule is input with a set frequency of on and off pulses, so that the new submodule is put into operation and cut off at the set frequency. In this way, it can better meet the operational requirements of the actual project of the energy storage valve. In this strategy, the control method of the present application may also include: obtaining the dynamic performance of the second submodule at different frequencies and the response of the energy storage system. That is, under the fixed frequency control strategy, the new submodule will be put into operation and cut off at a specific frequency, so that the dynamic performance of the new submodule at each frequency can be fully tested, such as loss, junction temperature fluctuation, thermal effect, peak voltage and current, etc. At the same time, the response of the system when the new submodule is switched on and off at different frequencies can also be tested, thereby providing convenient conditions for improving the energy storage system.

[0064] In some embodiments, this step may include: executing a charging strategy when the initial charging current of the second submodule is greater than a charging threshold value; under the charging strategy, if the real-time charging current is not greater than the charging threshold value, cutting off the second submodule; if the real-time charging current is greater than the charging threshold value, executing a discharging strategy when the battery normalization scoring parameter is less than or equal to a preset scoring limit; and controlling the second submodule to remain in an engaged state when the battery normalization scoring parameter is greater than the preset scoring limit; executing a discharging strategy when the initial discharge current of the second submodule is greater than the discharge threshold value; under the discharge strategy, if the real-time discharge current is not greater than the discharge threshold value, cutting off the second submodule; and if the real-time discharge current is greater than the discharge threshold value, executing a charging strategy when the battery normalization scoring parameter is less than or equal to the preset scoring limit; and controlling the second submodule to remain in an engaged state when the battery normalization scoring parameter is greater than the preset scoring limit. This is a control strategy for achieving full-condition SOX control. Due to the larger capacity of the new submodule, its SOX value changes more slowly than that of the existing submodule. Therefore, when the SOX value of the existing submodule drops to the limit, the SOX value of the new submodule often has some margin left. Therefore, a full-condition SOX control strategy is designed. First, the initial charge and discharge state of the current submodule is determined based on whether the charge and discharge currents are greater than a pre-set current threshold. The strategy then locks into one state: charging or discharging. For example, when the initial charge current of the new submodule exceeds the charge threshold, the system determines the initial state of the new submodule as charging and locks the charge strategy. When the subsequent real-time charge current exceeds the charge threshold, the new submodule is engaged. When the subsequent real-time charge current is less than or equal to the charge threshold, the new submodule is disengaged. This cycle continues until the SOX value of the new submodule drops to the lower SOX limit. At this point, the strategy switches to the discharge strategy and locks into place, repeating the cycle. This allows the new submodule to operate within the full SOX range, providing further convenient conditions for testing the battery performance of the new submodule.

[0065] Of course, in addition to the three specific control strategies mentioned above, different control strategies can also be set according to other performance test requirements of the new sub-module, and this application does not impose any restrictions on this.

[0066] Furthermore, in some embodiments, the control method of the present application may further include: after controlling the second submodule to remain in the active state, calculating the required number of first submodules to be active based on the real-time voltage of the second submodule and the average capacitor voltage of the first submodule. In other words, when a new submodule is active, the number of existing submodules to be active is calculated based on the real-time voltage of the new submodule and the average capacitor voltage of the existing submodules, thereby controlling the switching of the existing submodules and minimizing voltage fluctuations caused by switching in new submodules with higher port voltages.

[0067] Furthermore, the aforementioned calculation of the required number of first submodules to be deployed based on the real-time voltage of the second submodule and the average capacitor voltage of the first submodule can include: dividing the difference obtained by subtracting the real-time voltage of the second submodule from the DC voltage modulation wave by the average capacitor voltage of the first submodule to obtain the required number of first submodules to be deployed. In other words, the number of existing submodules to be deployed = (DC voltage modulation wave - real-time voltage of the new submodule) / average capacitor voltage of the existing submodule. In this way, the number of existing submodules that should be deployed when the new submodule is deployed can be quickly calculated.

[0068] In an embodiment of the present application, for an energy storage system comprising several first submodules, when a second submodule is put into operation, the normalized battery scoring parameters of the second submodule are obtained. Then, based on preset scoring limits, the second submodule is controlled to maintain its operation or be removed. Control of the second submodule is achieved by fully considering the battery capacity of the second submodule, thereby achieving coordinated control of different submodules. This allows for thorough testing of the performance of new submodules, facilitating a stable response for the entire system.

[0069] In order to explain the solution of this application in more detail, a specific embodiment is introduced below:

[0070] In this embodiment, a single new submodule is added to the existing energy storage valve for performance testing. The existing energy storage valve originally contains several existing submodules, wherein the port voltage of the new submodule is 2.5kV, which is higher than the port voltage of the existing submodule of 1.5kV. Therefore, for the convenience of distinction, the new submodule is referred to as the 2.5kV submodule and the existing submodule is referred to as the 1.5kV submodule. Before the 2.5kV submodule is added, the control strategy of the energy storage valve for the 1.5kV submodule is to determine the number of battery modules that should be put into the system in the current control cycle based on the reference voltage and the average capacitance voltage of the submodule, and then determine the specific submodules to be balanced by the system in the current control cycle and switch them on and off in combination with the number of submodules required to be put into the previous cycle. Taking into account that after the addition of the 2.5kV submodule, the existing energy storage valve is composed of different types of submodules. Therefore, this embodiment provides a coordinated control strategy for different submodules based on a high-voltage, large-capacity energy storage system, so that the performance of the new submodule can be fully tested and the bus voltage fluctuation is within a safe range. This embodiment is divided into the following two parts:

[0071] Part 1 is to classify the control strategies of new submodules into three types based on the different performance test requirements of new submodules, namely, maximum available control strategy, fixed frequency control strategy and SOX full-operating condition control strategy; among them:

[0072] The process of maximizing the available control strategies is shown in Figure 3. The process includes:

[0073] S301: Determine whether the SOX value of the 2.5kV submodule is less than or equal to the SOX lower limit value. If yes, execute S302; otherwise, execute S303.

[0074] S302, remove the 2.5kV submodule;

[0075] S303. Put the 2.5kV submodule into operation.

[0076] The process of the fixed frequency control strategy is shown in Figure 4. The process includes:

[0077] S401. Set the switching frequency of the 2.5kV submodule to x Hz; where x represents a certain value;

[0078] S402: Determine whether the SOX value of the 2.5kV submodule is less than or equal to the SOX lower limit value. If yes, execute S403; otherwise, execute S404.

[0079] S403, remove the 2.5kV submodule;

[0080] S404. Switch the 2.5 kV submodule at a frequency of x Hz.

[0081] The process of the SOX full-condition control strategy is shown in Figure 5. The process includes:

[0082] S501, determine whether the initial state of the 2.5kV submodule is charging, if yes, execute S502, otherwise execute S503;

[0083] S502: Determine whether the initial charging current of the 2.5 kV submodule is greater than the charging threshold value. If yes, execute S504; otherwise, execute S512.

[0084] S503: Determine whether the initial discharge current of the 2.5 kV submodule is greater than the discharge threshold value. If yes, execute S509; otherwise, execute S512.

[0085] S504, enter charging strategy;

[0086] S505: Determine whether the real-time charging current of the 2.5 kV submodule is greater than the charging threshold value. If yes, execute S506; otherwise, execute S507.

[0087] S506: Determine whether the SOX value of the 2.5kV submodule in the charging state is less than or equal to the SOX lower limit value. If yes, execute S509; otherwise, execute S508.

[0088] S507, remove the 2.5kV submodule;

[0089] S508, put into operation 2.5kV submodule;

[0090] S509, entering the discharge strategy;

[0091] S510: Determine whether the real-time discharge current of the 2.5 kV submodule is greater than the discharge threshold value. If so, execute S511; otherwise, execute S507.

[0092] S511, determine whether the SOX value of the 2.5kV submodule in the discharge state is less than or equal to the SOX lower limit value. If yes, execute S504; otherwise, execute S508;

[0093] S512: Control the 2.5kV submodule to maintain its original state.

[0094] Part two is a coordinated control strategy, which combines the original control strategy with the new sub-module control strategy. Depending on whether the new sub-module is put into use, the number of existing sub-modules that should be put into use is calculated separately, so as to minimize the voltage fluctuations caused by the new sub-module with a larger port voltage. Specifically, when the new sub-module is not put into use, the original control strategy is maintained; when the new sub-module is put into use, the DC voltage modulation wave is subtracted from the real-time voltage of the new sub-module, and then divided by the average capacitor voltage of the existing sub-module to calculate the number of existing sub-modules put into use, and then the new sub-module control strategy is adopted according to the different test requirements of the new sub-module.

[0095] Corresponding to the embodiments of the aforementioned method, the present application also provides embodiments of a control device for an energy storage system and a terminal used therein:

[0096] As shown in FIG6 , FIG6 is a block diagram of a control device for an energy storage system provided in an embodiment of the present application. The energy storage system includes several first submodules; the device includes:

[0097] An acquisition module 61 is configured to acquire a battery normalization scoring parameter of a second submodule including a battery cell when the energy storage system is added with the second submodule; the battery normalization scoring parameter is a comprehensive scoring value representing the battery operating performance;

[0098] The control module 62 is configured to control the second submodule to remain in an active state or to disconnect the second submodule according to the battery normalization score parameter and a preset score limit.

[0099] The implementation process of the functions and effects of each module in the above-mentioned device is specifically described in the implementation process of the corresponding steps in the above-mentioned method, and will not be repeated here.

[0100] The present application also provides an electronic device. Please refer to Figure 7, which is a structural block diagram of an electronic device provided in an embodiment of the present application. The electronic device may include a processor 710, a communication interface 720, a memory 730, and at least one communication bus 740. Among them, the communication bus 740 is used to realize direct connection and communication between these components. Among them, the communication interface 720 of the electronic device in the embodiment of the present application is used to communicate signaling or data with other node devices. The processor 710 can be an integrated circuit chip with signal processing capabilities.

[0101] The processor 710 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application. The processor 710 can be a microprocessor, or it can be any conventional processor.

[0102] The memory 730 may be, but is not limited to, a random access memory (RAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), etc. The memory 730 stores computer-readable instructions. When the processor 710 executes the computer-readable instructions, the electronic device may perform the steps of the method embodiment of FIG. 1 .

[0103] Optionally, the electronic device may further include a storage controller and an input / output unit.

[0104] The memory 730, storage controller, processor 710, peripheral interface, and input / output units are electrically connected to each other directly or indirectly to enable data transmission or interaction. For example, these components can be electrically connected to each other via one or more communication buses 740. The processor 710 is used to execute executable modules stored in the memory 730, such as software function modules or computer programs included in the electronic device.

[0105] The input and output unit is used to provide users with the ability to create tasks and to create optional time periods or preset execution times for the tasks to enable interaction between the user and the server. The input and output unit can be, but is not limited to, a mouse and a keyboard.

[0106] It is understood that the structure shown in Figure 7 is merely illustrative, and the electronic device may include more or fewer components than shown in Figure 7, or have a configuration different from that shown in Figure 7. Each component shown in Figure 7 may be implemented using hardware, software, or a combination thereof.

[0107] An embodiment of the present application provides an energy storage system, which includes an energy storage unit and a control unit; the control unit adopts an electronic device as shown in Figure 7.

[0108] An embodiment of the present application further provides a storage medium having instructions stored thereon. When the instructions are run on a computer, the computer program is executed by a processor to implement the method described in the method embodiment. To avoid repetition, details are not given here.

[0109] The present application also provides a computer program product, which, when running on a computer, enables the computer to execute the method described in the method embodiment.

[0110] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions and operations of the devices, methods and computer program products according to the multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0111] In addition, the functional modules in each embodiment of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0112] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0113] The foregoing is merely an embodiment of the present application and is not intended to limit the scope of protection of the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included within the scope of protection of the present application. It should be noted that similar reference numerals and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined or explained in subsequent figures.

[0114] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

[0115] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

Claims

1. A control method for an energy storage system, wherein the energy storage system comprises a plurality of first submodules; the method comprises: In the case where a second submodule including a battery cell is added to the energy storage system, obtaining a battery normalization score parameter of the second submodule; The battery normalization scoring parameter is a comprehensive scoring value that characterizes the battery operating performance; According to the battery normalized scoring parameter and a preset scoring limit, the second submodule is controlled to remain in an engaged state or to be removed.

2. The method according to claim 1, wherein: The first submodule and the second submodule are energy storage submodules with different terminal voltages and different capacities.

3. The method according to claim 1 or 2, wherein: The battery normalization scoring parameter is calculated based on at least two indicators of battery state of charge, battery health, battery current inconsistency, and battery power capability, and a weight corresponding to each of the at least two indicators.

4. The method according to any one of claims 1 to 3, wherein: The controlling the second submodule to maintain the input state or to remove the second submodule according to the battery normalization score parameter and the preset score limit value includes: When the battery normalization score parameter is greater than a preset score limit, controlling the second submodule to remain in an engaged state; When the battery normalized score parameter is not greater than a preset score limit, the second submodule is cut off.

5. The method according to any one of claims 1 to 3, wherein: The controlling the second submodule to maintain the input state or to remove the second submodule according to the battery normalization score parameter and the preset score limit value includes: When the battery normalization score parameter is greater than a preset score limit, the second submodule is controlled to remain in the activated state or to be removed at a set frequency.

6. The method according to claim 5, wherein: The method further comprises: The dynamic performance of the second submodule at different frequencies and the response of the energy storage system are obtained.

7. The method according to any one of claims 1 to 3, wherein: The controlling the second submodule to maintain the input state or to remove the second submodule according to the battery normalization score parameter and the preset score limit value includes: In the case where the initial charging current of the second submodule is greater than the charging threshold value, a charging strategy is executed; under the charging strategy, if the real-time charging current is not greater than the charging threshold value, the second submodule is removed; if the real-time charging current is greater than the charging threshold value, a discharging strategy is executed when the battery normalization scoring parameter is less than or equal to a preset scoring limit value; and when the battery normalization scoring parameter is greater than the preset scoring limit value, the second submodule is controlled to remain in an engaged state; When the initial discharge current of the second submodule is greater than the discharge threshold value, the discharge strategy is executed; under the discharge strategy, if the real-time discharge current is not greater than the discharge threshold value, the second submodule is cut off; if the real-time discharge current is greater than the discharge threshold value, when the battery normalization score parameter is less than or equal to the preset score limit value, the charging strategy is executed; when the battery normalization score parameter is greater than the preset score limit value, the second submodule is controlled to remain in the engaged state.

8. The method according to any one of claims 1 to 7, wherein: The method further comprises: After controlling the second submodule to maintain the input state, the input requirement quantity of the first submodule is calculated according to the real-time voltage of the second submodule and the average value of the capacitor voltage of the first submodule.

9. The method according to claim 8, wherein: The step of calculating the required input quantity of the first submodule according to the real-time voltage of the second submodule and the average value of the capacitor voltage of the first submodule includes: The difference obtained by subtracting the real-time voltage of the second submodule from the DC voltage modulation wave is divided by the average value of the capacitor voltage of the first submodule to obtain the required input quantity of the first submodule.

10. A control device for an energy storage system, the energy storage system comprising a plurality of first submodules; the device comprising: An acquisition module, configured to acquire a battery normalization score parameter of a second submodule when a second submodule including a battery cell is added to the energy storage system; The battery normalization scoring parameter is a comprehensive scoring value that characterizes the battery operating performance; The control module is used to control the second submodule to maintain the input state or cut off the second submodule according to the battery normalization score parameter and the preset score limit.

11. A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the method according to any one of claims 1 to 9.

12. An electronic device comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 9 is implemented.

13. An energy storage system, comprising an energy storage unit and a control unit; the control unit adopts the electronic device as claimed in claim 12.

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