Balancing method, terminal equipment, energy storage system and computer readable storage medium

Abstract

The invention is suitable for the technical field of energy storage, and provides a balancing method, terminal equipment, an energy storage system and a computer readable storage medium, and the method comprises the steps: obtaining the input number of a current control period and the input number of a previous control period; determining the switching state of the energy storage system according to the input quantity of the current control period and the input quantity of the previous control period; if the switching state of the energy storage system is a switching-out state, a target switching-out sub-module is determined according to an alternate switching-out mode, the target switching-out sub-module is controlled to be switched out from the energy storage system, and under the condition that the energy storage sub-module needs to be switched out in the current control period, the switched-out sub-module is switched out according to a balancing mode that the switched-in energy storage sub-module is switched out in turns. The average switching frequency and loss of the energy storage sub-module can be greatly reduced, so that the service life of the energy storage system is prolonged.

Description

Technical Field

[0001] The present application belongs to the field of energy storage technology, and in particular, relates to an energy storage submodule balancing method, a terminal device, an energy storage system, and a computer-readable storage medium. Background Art

[0002] Compared with traditional energy storage systems, high-voltage and large-capacity energy storage systems have stronger regulation capabilities for flexible DC transmission systems, are more suitable for the application scenarios of offshore wind power output via flexible DC, have lower system network losses, higher economic benefits, and higher operational reliability. Therefore, high-voltage and large-capacity energy storage systems have important research significance for new power systems based on new energy.

[0003] At present, high-voltage and large-capacitance energy storage systems generate high switching losses when balancing energy storage sub-modules, which affects the service life of power devices and systems. Summary of the invention

[0004] In view of the above problems, the present application provides a balancing method, a terminal device, an energy storage system and a computer-readable storage medium, which can minimize the average switching times and switching losses of the energy storage submodules while achieving balancing of the energy storage submodules, thereby extending the service life of the energy storage system.

[0005] In a first aspect, an embodiment of the present application provides a balancing method, including:

[0006] Get the input quantity of the current control cycle and the input quantity of the previous control cycle;

[0007] Determine the switching state of the energy storage system according to the input quantity of the current control cycle and the input quantity of the previous control cycle;

[0008] If the switching state of the energy storage system is a cut-out state, a target cut-out submodule is determined according to a cut-out method in turn, and the target cut-out submodule is controlled to be cut out from the energy storage system.

[0009] In an embodiment of the present application, when the energy storage sub-module needs to be switched out in the current control cycle, the average switching frequency and loss of the energy storage sub-module can be greatly reduced by switching out the already put into operation energy storage sub-module in a balanced manner, thereby increasing the service life of the energy storage system.

[0010] In some possible implementations of the first aspect, if the switching state of the energy storage system is a switching-out state, after determining a target switching-out submodule according to a switching-out method, and controlling the target switching-out submodule to be switched out of the energy storage system, the method further includes:

[0011] If the switching state of the energy storage system is the on-state, a target on-sub module is determined according to a balance priority method, and the target on-sub module is controlled to be put into the energy storage system.

[0012] In an embodiment of the present application, when the energy storage system needs to put into use an energy storage submodule, based on a balance priority approach, a target energy storage submodule that is beneficial to adjusting the balance state of the energy storage system can be put into use first, so that the energy storage system can achieve better balance.

[0013] In some possible implementations of the first aspect, if the switching state of the energy storage system is the switched-on state, determining a target switched-on submodule according to a balanced priority manner, and controlling the target switched-on submodule to be switched into the energy storage system, includes:

[0014] Sorting the target parameters of all the switched-out energy storage submodules in descending order according to their priorities to obtain a sorting result;

[0015] Determine the first |Δn| switched-out energy storage submodules of the sorting result as target input submodules, wherein Δn is the difference between the input quantity of the current control cycle and the input quantity of the previous control cycle;

[0016] The target input submodule is modulated.

[0017] In an embodiment of the present application, when the energy storage system needs to invest in energy storage sub-modules, the priority of each energy storage sub-module can be set based on the target parameters, and then the target energy storage sub-module that is beneficial to adjusting the equilibrium state of the energy storage system is preferentially invested, so that the energy storage system can achieve better balance.

[0018] In some possible implementations of the first aspect, determining the switching state of the energy storage system according to the number of inputs in the current control cycle and the number of inputs in the previous control cycle includes:

[0019] Calculate the difference between the input quantity of the current control cycle and the input quantity of the previous control cycle to obtain the submodule change amount;

[0020] If the submodule change amount is greater than 0, it is determined that the switching state of the energy storage system is the switching state;

[0021] If the submodule variation is less than 0, it is determined that the switching state of the energy storage system is a switching-out state.

[0022] In some possible implementations of the first aspect, the switching state of the energy storage system further includes an unchanged state, and the balancing method further includes:

[0023] If the switching state of the energy storage system is unchanged, the states of the energy storage submodules of the energy storage system are maintained unchanged.

[0024] In the embodiment of the present application, when the switching state of the energy storage system is unchanged, only the state of each energy storage submodule of the energy storage system is maintained unchanged, which can reduce the switching operation of the energy storage submodule and reduce the average switching frequency and loss of the energy storage submodule.

[0025] In a second aspect, an embodiment of the present application provides another balancing method, including:

[0026] Get the input quantity of the current control cycle and the input quantity of the previous control cycle;

[0027] Determine the submodule change amount and the switching state of the energy storage system according to the input quantity of the current control cycle and the input quantity of the previous control cycle;

[0028] According to the submodule variation and the switching state of the energy storage system, a target switching submodule is determined in a balanced priority manner;

[0029] If the switching times of the target switching submodule is less than the switching times threshold, a switching operation is performed on the target switching submodule.

[0030] The target switching submodule is first determined by means of priority balancing, and the switching operation is performed on the target switching submodule only when the switching times of the target switching submodule is less than the switching times threshold. The switching times of the energy storage submodule can be limited while ensuring balance, thereby reducing the average switching frequency and loss of the energy storage submodule and increasing the service life of the energy storage system.

[0031] In some possible implementations of the second aspect, when the switching state of the energy storage system is in the switched-on state, determining the target switching submodule in a balanced priority manner according to the submodule variation and the switching state of the energy storage system includes:

[0032] Sort the target parameters of all the switched-out energy storage submodules in descending order according to their priorities to obtain a sorting result;

[0033] The first |Δn| switched-out energy storage submodules in the sorting result are determined as target input submodules, wherein Δn is the difference between the input quantity in the current control cycle and the input quantity in the previous control cycle.

[0034] In the embodiment of the present application, considering the equilibrium state of the energy storage system, after determining the above-mentioned sorting result, the energy storage submodules at the front of the sorting are put into the energy storage system, which can adjust the equilibrium state of the energy storage system more quickly. Therefore, the first |Δn| cut-out energy storage submodules in the sorting result are determined as the target submodules to be put into use, which can achieve system equilibrium more quickly.

[0035] In some possible implementations of the second aspect, when the switching state of the energy storage system is a cut-out state, determining a target switching submodule in a balanced priority manner according to the submodule variation and the switching state of the energy storage system includes:

[0036] Sort the target parameters of all the energy storage submodules that have been put into use in descending order according to their priorities to obtain the sorting result;

[0037] The last |Δn| put-in-service energy storage submodules of the sorting result are determined as target cut-out submodules, wherein Δn is the difference between the put-in-service quantity in the current control cycle and the put-in-service quantity in the previous control cycle.

[0038] In the embodiment of the present application, considering the equilibrium state of the energy storage system, after determining the above-mentioned sorting result, the energy storage submodules that have been put into use at the back of the sorting are cut out from the energy storage system, which can adjust the equilibrium state of the energy storage system more quickly. Therefore, the last |Δn| energy storage submodules in the sorting result are determined as the target cut-out submodules, which can achieve system equilibrium more quickly.

[0039] In some possible implementations of the second aspect, after determining the target switching submodule according to the submodule variation and the switching state of the energy storage system in a balanced priority manner, the method further includes:

[0040] If the switching times of the target switching submodule is greater than or equal to the switching times threshold, the target switching submodule is kept in a switched-out state, and the target switching submodule is controlled to exit the switching queue.

[0041] In the embodiment of the present application, since the switching times of the target switching submodule is greater than the switching times threshold, if the switching operation is continued, it may cause damage to the energy storage submodule. Therefore, after determining that the switching times of the target switching submodule is greater than or equal to the switching times threshold, it is necessary to control the target switching submodule to exit the switching queue, so that the energy storage valve controller will not sort the target switching submodule when sorting the energy storage submodules, that is, the sorting result obtained in this way will not include the above-mentioned target switching submodule, so that the judgment steps for the same energy storage submodule that has exceeded the switching times threshold can be reduced, and the loss of computing resources of the controller can be reduced.

[0042] In some possible implementations of the second aspect, if the switching number of the target switching submodule is greater than or equal to the switching number threshold, keeping the target switching submodule in a switched-out state and controlling the target switching submodule to exit a switching queue includes:

[0043] The target switching submodule is kept in a switched-out state within the thermal stabilization time, and the target switching submodule is controlled to exit the switching queue.

[0044] In an embodiment of the present application, in order to reduce the possibility of damage to the energy storage submodule, the above-mentioned keeping the target switching submodule in a switched-out state and controlling the target switching submodule to exit the switching queue can specifically be keeping the target switching submodule in a switched-out state within a thermal stabilization time and controlling the target switching submodule to exit the switching queue.

[0045] In some possible implementations of the second aspect, after if the switching number of the target switching submodule is greater than or equal to the switching number threshold, keeping the target switching submodule in a switched-out state and controlling the target switching submodule to exit a switching queue, the method further includes:

[0046] The target switching submodule is re-determined according to the updated sorting result.

[0047] In the embodiment of the present application, after the energy storage submodules exceeding the switching number threshold are withdrawn from the switching queue, an updated sorting result can be obtained, so that Δn energy storage submodules can be determined as target switching submodules according to the updated sorting result.

[0048] In some possible implementations of the second aspect, the balancing method further includes:

[0049] When the next calculation cycle starts, the switching times of each energy storage submodule in the energy storage system are reset, and the ranking results of each energy storage submodule in the energy storage system are reacquired.

[0050] In the embodiment of the present application, at the beginning of the next calculation cycle, all energy storage sub-modules are put back into order, and the switching times of each energy storage sub-module in the energy storage system are reset, so that each energy storage sub-module in the energy storage system can be switched again according to the balancing demand, and the switching times of the energy storage sub-modules in the energy storage system can be ensured not to exceed the switching times threshold, thereby protecting the energy storage sub-modules. While achieving balancing, the loss of the energy storage sub-modules is controlled within an acceptable range, thereby extending the service life of the energy storage system.

[0051] In some possible implementations of the second aspect, the balancing method further includes:

[0052] The switching times threshold is determined according to a transient thermal resistance curve and a steady-state junction temperature upper limit of a power device of the energy storage submodule.

[0053] In a third aspect, an embodiment of the present application provides a terminal 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, it implements the balancing method as described in the first aspect or any optional aspect of the first aspect, or the balancing method as described in the second aspect or any optional aspect of the second aspect.

[0054] In a fourth aspect, an embodiment of the present application provides an energy storage system, which includes a plurality of energy storage sub-modules and a terminal device as described in the third aspect.

[0055] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the balancing method as described in the first aspect or any optional manner of the first aspect or the balancing method as described in the second aspect or any optional manner of the second aspect is implemented.

[0056] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0058] Figure 1 A schematic diagram of the architecture of the MMC type energy storage system provided in the embodiment of the present application;

[0059] Figure 2 A schematic diagram of the architecture of a cascade energy storage system provided in an embodiment of the present application;

[0060] Figure 3 A schematic diagram of the architecture of a DC direct-mounted energy storage system provided in an embodiment of the present application;

[0061] Figure 4 A schematic diagram of the structure of a half-bridge power module of an energy storage system provided in an embodiment of the present application;

[0062] Figure 5A schematic diagram of the structure of a full-bridge power module of an energy storage system provided in an embodiment of the present application;

[0063] Figure 6 A schematic diagram of the implementation flow of the balancing method provided in the embodiment of the present application;

[0064] Figure 7 A schematic diagram of the implementation flow of the balancing method provided in other embodiments of the present application;

[0065] Figure 8 A schematic diagram of the implementation flow of S14 in the equalization method provided in other embodiments of the present application;

[0066] Fig. 9 A schematic diagram of the implementation flow of the balancing method provided in other embodiments of the present application;

[0067] Fig.10 A schematic diagram of the implementation flow of S23 in the equalization method provided in some embodiments of the present application;

[0068] Fig.11 A schematic diagram of the implementation flow of S23 in the balancing method provided in other embodiments of the present application;

[0069] Fig.12 A schematic diagram of the implementation flow of the balancing method provided in other embodiments of the present application;

[0070] Fig.13 A schematic diagram of the structure of an equalizing device provided in some embodiments of the present application;

[0071] Fig.14 A schematic diagram of the structure of a terminal device provided for some embodiments of the present application. DETAILED DESCRIPTION

[0072] The following embodiments of the technical solution of the present application will be described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0073] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field 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" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0074] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0075] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0076] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0077] 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).

[0078] 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. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which 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 referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0079] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0080] Energy storage refers to the process of storing energy through a medium or device and releasing it when needed. Compared with traditional energy storage systems, high-voltage and large-capacity energy storage systems have stronger regulation capabilities for flexible DC transmission systems, are more suitable for application scenarios of offshore wind power output via flexible DC, have lower system network losses, higher economic benefits, and higher operational reliability.

[0081] High-voltage, large-capacity energy storage systems include, but are not limited to, modular multilevel converter (MMC) energy storage systems, cascade energy storage systems, and DC direct-mounted energy storage systems.

[0082] For example, see Figures 1 to 3 , which are schematic architecture diagrams of MMC type energy storage system, cascade energy storage system and DC direct-mounted energy storage system respectively.

[0083] like Figures 1 to 3 It can be seen that the above-mentioned high-voltage and large-capacity energy storage system 1 may include a plurality of energy storage submodules SM, for example Figure 1 The MMC type energy storage system 11 includes 6*N energy storage submodules SM ( Figure 1 In the figure, they are represented as 6 groups SM1 to SMN), and Figure 2 The cascade energy storage system 12 includes 3*N energy storage submodules SM ( Figure 2 In the figure, they are represented as 3 groups SM1~SMN), and Figure 3 The DC direct-mounted energy storage system 13 includes N energy storage submodules SM ( Figure 3 are represented as SM1~SMN respectively).

[0084] The energy storage submodule SM includes a power module 20 and a battery module 30 .

[0085] The power module 20 may be implemented as follows: Figure 4 The half-bridge power module shown in FIG. 1 , the corresponding energy storage submodule SM is a half-bridge energy storage submodule; the power module 20 may also be a half-bridge power storage submodule. Figure 5 The full-bridge power module shown in FIG. 1 , then the corresponding energy storage module SM is a full-bridge energy storage submodule.

[0086] The battery module 30 may be a single-branch series-connected battery module or a multi-branch series-parallel-connected battery module.

[0087] Wherein, N is an integer greater than or equal to 1.

[0088] In order to further improve the system power and capacity of high-voltage and large-capacity energy storage systems, this can be achieved by adding cascaded energy storage sub-modules. How to achieve balance between multiple energy storage sub-modules is an important issue in the application of energy storage systems.

[0089] In energy storage systems, the balance of energy storage submodules is usually achieved through phase-shifted pulse width modulation (PSPWM). However, in the case of cascading multiple energy storage submodules in the energy storage system, the control algorithm design of the PSPWM modulation strategy becomes more complicated and will also cause greater losses. At present, the balance of multiple cascaded energy storage submodules is achieved by the nearest level modulation (NLM) modulation strategy. The NLM modulation strategy can reduce the switching frequency and achieve dynamic balance of multiple energy storage submodules.

[0090] However, since the modulation process of the high-voltage and large-capacity energy storage system will generate high-frequency modulation signals (such as modulation signals with a frequency of more than 100Hz) to the energy storage system or a single energy storage submodule, it will cause frequent switching of the energy storage submodule, affecting the service life of the power device and the system. That is, the above-mentioned balancing methods cannot be directly applied to high-voltage and large-capacity energy storage systems, and it is now urgent to provide a balancing method that can reduce the average switching frequency of the submodule.

[0091] Based on the above considerations, in order to solve the problem that high switching losses will be generated when balancing the energy storage sub-modules in the high-voltage and large-capacitance energy storage system, affecting the service life of the power devices and the system, the embodiment of the present application proposes a balancing method. When the energy storage sub-module needs to be cut out in the current control cycle, the balancing method of cutting out the already put into use energy storage sub-modules in turn can greatly reduce the average switching frequency and loss of the energy storage sub-module, thereby improving the service life of the energy storage system.

[0092] The balancing method provided in the embodiment of the present application can be applied to the above energy storage system, and specifically the balancing method provided in the embodiment of the present application can be executed by the energy storage valve controller of the energy storage system. The above energy storage system 1 includes at least two energy storage submodules SM, which are connected in series.

[0093] See also Figure 6 , Figure 6 The following is a schematic implementation flow chart of an equalization method provided in some embodiments of the present application. Figure 6 As shown, the above-mentioned equalization method may include S11-S13, which are described in detail as follows:

[0094] S11: Obtain the input quantity of the current control cycle and the input quantity of the previous control cycle.

[0095] In an embodiment of the present application, in each control cycle, the energy storage valve controller determines the number of energy storage sub-modules that need to be invested in the energy storage system in the current control cycle based on the reference voltage of the energy storage system and the capacitor voltage of each energy storage sub-module, that is, the investment number of the current control cycle mentioned above.

[0096] In a specific application, the input quantity of the current control cycle can be determined according to the reference voltage of the current cycle and the average capacitor voltage of each energy storage submodule.

[0097] Specifically, the input quantity n of the current control cycle can be expressed as: n=round(U ref / U c ), where U ref is the reference voltage of the current control cycle, U c is the average capacitor voltage of each energy storage submodule. round() is the rounding function.

[0098] In a specific application, the reference voltage of the current control cycle can be obtained by an inner and outer loop proportional-integral regulation algorithm.

[0099] In a specific application, the average capacitor voltage of each energy storage submodule can be obtained by acquiring the capacitor voltage of each energy storage submodule in the energy storage system and then calculating it through an average value function.

[0100] In specific applications, the energy storage valve controller calculates the input quantity corresponding to each control cycle in each control cycle, and can record the input quantity of each control cycle calculated by it, or record the input quantity of the most recent control cycles. After the current control cycle starts, the input quantity of the current control cycle can be calculated based on the reference voltage of the current cycle and the average capacitor voltage of each energy storage sub-module, and the input quantity of the previous control cycle can be obtained.

[0101] S12: Determine the switching state of the energy storage system according to the number of inputs in the current control cycle and the number of inputs in the previous control cycle.

[0102] In a specific application, the switching state may include an on state and a off state.

[0103] In specific applications, the energy storage valve controller can first calculate the difference between the input quantity of the current control cycle and the input quantity of the previous control cycle, determine the difference as the submodule change amount, and then determine the switching state of the energy storage system according to the submodule change amount. That is, if the submodule change amount is greater than 0, the switching state of the energy storage system is determined to be the input state; if the submodule change amount is less than 0, the switching state of the energy storage system is determined to be the cut-out state.

[0104] Specifically, Δn = n k -nk-1 ; Among them, Δn is the submodule change, n k is the input quantity of the current control cycle, n k-1 is the input quantity of the previous control period.

[0105] In some embodiments of the present application, the energy storage valve controller can also directly determine the size of the input quantity of the current control cycle and the input quantity of the previous control cycle to determine the switching state of the energy storage system. That is, if the input quantity of the current control cycle is greater than the input quantity of the previous control cycle, the switching state of the energy storage system is determined to be the input state; if the input quantity of the current control cycle is less than the input quantity of the previous control cycle, the switching state of the energy storage system is determined to be the cut-out state.

[0106] In the embodiment of the present application, if the switching state of the energy storage system is the switched-on state, it indicates that in the current control cycle, it is necessary to select an energy storage submodule from an unswitched energy storage submodule and put it into the energy storage system; if the switching state of the energy storage system is the switched-off state, it indicates that in the current control cycle, it is necessary to select and switch out an energy storage submodule that has been put into the energy storage system from the energy storage system.

[0107] S13: If the switching state of the energy storage system is a cut-out state, a target cut-out submodule is determined according to a cut-out method in turn, and the target cut-out submodule is controlled to be cut out from the energy storage system.

[0108] In the embodiment of the present application, the above-mentioned method of switching out in turns refers to determining the energy storage sub-modules that have been put into use in the energy storage system as target switching-out sub-modules in turn.

[0109] Exemplarily, assume that the energy storage system includes 6 energy storage sub-modules, among which the energy storage sub-modules that have been put into operation include {a first energy storage sub-module SM1, a second energy storage sub-module SM2, a third energy storage sub-module SM3, and a fourth energy storage sub-module SM4}. If Δn is determined to be -1, it means that an energy storage sub-module needs to be cut out in the current control cycle. Assuming that the fourth energy storage sub-module SM4 has been cut out in the last two rounds, the fourth energy storage sub-module SM4 is put into operation in the last control cycle (that is, the fourth energy storage sub-module has been turned once). Here, the third energy storage sub-module SM3 will be determined as the target cut-out sub-module, and the energy storage valve controller will control the third energy storage sub-module SM3 to be cut out.

[0110] In the embodiment of the present application, the above-mentioned control of cutting out the target cut-out submodule from the energy storage system may be that the energy storage valve controller modulates the target cut-out submodule based on a modulation strategy.

[0111] Specifically, the above-mentioned modulation strategies include but are not limited to specific harmonic elimination step wave (selective harmonic elimination pulse width modulation, SHESM) modulation strategy, nearest level approximation modulation strategy, space vector control strategy, carrier disposition pulse width modulation (carrier disposition pulse width modulation) modulation strategy, carrier phase-shift PWM modulation (carrier phase-shift pulse width modulation) modulation strategy, etc.

[0112] In the embodiment of the present application, when the energy storage submodule needs to be switched out in the current control cycle, the average switching frequency and loss of the energy storage submodule can be greatly reduced, thereby improving the service life of the energy storage system.

[0113] See also Figure 7 In one embodiment of the present application, the above-mentioned equalization method further includes the following steps:

[0114] S14: If the switching state of the energy storage system is the on-state, a target on-submodule is determined according to a balance priority method, and the target on-submodule is controlled to be put into the energy storage system.

[0115] In the embodiment of the present application, the above-mentioned determination of the target input submodule according to the balanced priority method can be specifically determined based on the priority of each energy storage submodule. In a specific application, the priority of each energy storage submodule can be determined according to the charge and discharge state of the energy storage system and the target parameter value of each energy storage submodule.

[0116] In the embodiment of the present application, the target parameter refers to a parameter that can reflect the working state of the energy storage submodule, and is a parameter considered when the energy storage system performs balancing, that is, the energy storage valve controller of the energy storage system performs system balancing based on the target parameter.

[0117] In a specific application, the above target parameters may include but are not limited to the state of charge (SOC) of the battery module of the energy storage submodule, the normalized parameters of the energy storage submodule, and the capacitor voltage of the energy storage submodule.

[0118] It should be noted that the normalized parameters of the energy storage submodule mentioned in the embodiment of the present application refer to parameters that can reflect the normalization degree of the energy storage submodule. The above normalized parameters can be determined by parameters such as the state of charge of the battery module of the energy storage submodule, the state of health (SOH) of the energy storage submodule, and the maximum power (SOP) of the battery module of the energy storage submodule during charging and discharging.

[0119] In specific applications, when the energy storage system is balanced and adjusted, the parameter to be selected as the target parameter can be determined according to the actual application scenario. For example, for traditional flexible direct current transmission scenarios, the capacitor voltage of the energy storage submodule can be selected as the target parameter; for application scenarios with a greater impact on the battery status, the SOC of the battery module of the energy storage submodule can be selected as the target parameter or the normalized parameter of the energy storage submodule can be selected as the target parameter.

[0120] Based on this, see Figure 8 , the above S14 may include the following steps:

[0121] S141: Sorting the target parameters of all energy storage submodules in descending order according to their priorities to obtain a sorting result.

[0122] In an embodiment of the present application, the priority of the energy storage submodule can be specifically determined according to the charge and discharge state of the energy storage system and the type of target parameter. Exemplarily, assuming that the charge and discharge state of the energy storage system is the charging state, when the target parameter is a normalized parameter, the higher the normalized parameter, the higher the priority of the energy storage submodule; when the target parameter is SOC, the lower the SOC, the higher the priority of the energy storage submodule; when the target parameter is the capacitor voltage of the energy storage submodule, the lower the capacitor voltage, the higher the priority of the energy storage submodule. Assuming that the charge and discharge state of the energy storage system is the discharge state, when the target parameter is a normalized parameter, the higher the normalized parameter, the higher the priority of the energy storage submodule; when the target parameter is SOC, the higher the SOC, the higher the priority of the energy storage submodule; when the target parameter is the capacitor voltage, the higher the capacitor voltage, the higher the priority of the energy storage submodule.

[0123] After determining the priority of each energy storage submodule, the priorities of the energy storage submodules are sorted in descending order, and the sorting result of the energy storage submodules in the current control cycle can be obtained.

[0124] S142: Determine the first |Δn| switched-out energy storage sub-modules in the sorting result as target input sub-modules.

[0125] In the embodiment of the present application, considering the equilibrium state of the energy storage system, after determining the above sorting result, the energy storage submodules at the front of the sorting are put into the energy storage system, which can adjust the equilibrium state of the energy storage system more quickly. Therefore, the first |Δn| cut-out energy storage submodules in the sorting result are determined as the target put-in submodules.

[0126] Exemplarily, assume that the energy storage system includes 8 energy storage sub-modules, among which the energy storage sub-modules that have been put into operation include {first energy storage sub-module SM1, second energy storage sub-module SM2, third energy storage sub-module SM3, fourth energy storage sub-module SM4}. If Δn is determined to be 1, it means that one energy storage sub-module needs to be put into operation in the current control cycle. Assuming that the remaining 4 energy storage sub-modules are sorted according to priority, the sorting results obtained are {fifth energy storage sub-module SM5, sixth energy storage sub-module SM6, seventh energy storage sub-module SM7, eighth energy storage sub-module SM8}, then the fifth energy storage sub-module SM5 can be determined as the target sub-module to be put into operation.

[0127] S143: Modulate the target input submodule.

[0128] In the embodiment of the present application, the above-mentioned modulation of the target input submodule from the energy storage system may be performed by the energy storage valve controller using a modulation strategy to modulate the target input submodule.

[0129] Specifically, the above-mentioned modulation strategies include but are not limited to specific harmonic elimination step wave (selective harmonic elimination pulse width modulation, SHESM) modulation strategy, nearest level approximation modulation strategy, space vector control strategy, carrier disposition pulse width modulation (carrier disposition pulse width modulation) modulation strategy, carrier phase-shift PWM modulation (carrier phase-shift pulse width modulation) modulation strategy, etc.

[0130] In an embodiment of the present application, when the energy storage system needs to invest in energy storage sub-modules, the priority of each energy storage sub-module can be set based on the target parameters, and then the target energy storage sub-module that is beneficial to adjusting the equilibrium state of the energy storage system is preferentially invested, so that the energy storage system can achieve better balance.

[0131] In an embodiment of the present application, if the switching state of the energy storage system is unchanged, the state of each energy storage sub-module of the energy storage system is maintained unchanged.

[0132] In a specific application, the states of the above-mentioned energy storage sub-modules include an engaged state and a non-engaged state. Maintaining the states of the above-mentioned energy storage sub-modules of the energy storage system unchanged means that for the energy storage sub-modules in the engaged state, the engaged state is maintained; for the energy storage sub-modules in the non-engaged state, the non-engaged state is maintained.

[0133] In the embodiment of the present application, when the switching state of the energy storage system is unchanged, only the state of each energy storage submodule of the energy storage system is maintained unchanged, which can reduce the switching operation of the energy storage submodule and reduce the average switching frequency and loss of the energy storage submodule.

[0134] See also Fig. 9 In an embodiment of the present application, different from the above embodiments, a balancing method provided in the embodiment of the present application may include the following steps:

[0135] S21: Obtain the input quantity of the current control cycle and the input quantity of the previous control cycle.

[0136] S22: Determine the submodule change amount and the switching state of the energy storage system according to the number of input modules in the current control cycle and the number of input modules in the previous control cycle.

[0137] For the relevant contents of steps S21 to S22, reference may be made to the description of steps S11 to S12, which will not be elaborated here.

[0138] S23: According to the submodule variation and the switching state of the energy storage system, a target switching submodule is determined in a balanced priority manner.

[0139] In the embodiment of the present application, the switching state of the energy storage system includes an on-state and a off-state, and the target switching submodule includes a target on-submodule and a target off-submodule.

[0140] In a specific application, if the submodule variation is greater than 0, the switching state of the energy storage system is determined to be the switched-on state; if the submodule variation is less than 0, the switching state of the energy storage system is determined to be the switched-off state.

[0141] In a specific application, if the submodule change amount is equal to 0, it is determined that the switching state of the energy storage system is a unchanged state.

[0142] In a specific application, if the switching state of the energy storage system is the switched-on state, the target switched-on submodule can be determined according to the submodule variation and the descending order sorting result of the priority of each energy storage submodule.

[0143] See also Fig.10 In one embodiment of the present application, when the switching state of the energy storage system is the switched-on state, the above S23 may include the following steps:

[0144] S231: Sort the target parameters of all energy storage submodules in descending order according to their priorities to obtain a sorting result;.

[0145] S232: Determine the first |Δn| switched-out energy storage sub-modules in the sorting result as target input sub-modules.

[0146] The contents of the above S231 to S232 can be found in the description of S141 to S142 and will not be elaborated here.

[0147] Considering the equilibrium state of the energy storage system, after determining the above sorting results, the energy storage submodules at the front of the sorting are put into the energy storage system, which can adjust the equilibrium state of the energy storage system more quickly. Therefore, the first |Δn| cut-out energy storage submodules in the sorting results are determined as the target submodules to achieve system equilibrium more quickly.

[0148] In a specific application, if the switching state of the energy storage system is a cut-out state, the target cut-out submodule can be determined according to the descending sorting result of the submodule variation and the priority of each energy storage submodule.

[0149] See also Fig.11 In one embodiment of the present application, when the switching state of the energy storage system is the cut-out state, the above S23 may include the following steps:

[0150] S233: Sort the target parameters of all energy storage submodules in descending order according to their priorities to obtain a sorting result;.

[0151] The content of the above S233 can be found in the description of S141 and will not be elaborated here.

[0152] S234: Determine the last |Δn| put-in-use energy storage sub-modules in the sorting result as target cut-out sub-modules.

[0153] In the embodiment of the present application, considering the equilibrium state of the energy storage system, after determining the above-mentioned sorting result, the energy storage submodules at the back of the sorting are cut out from the energy storage system, which can adjust the equilibrium state of the energy storage system more quickly. Therefore, the last |Δn| put-in-place energy storage submodules in the sorting result are determined as the target cut-out submodules, which can achieve system equilibrium more quickly.

[0154] Exemplarily, assume that the energy storage system includes 8 energy storage sub-modules, among which the energy storage sub-modules that have been put into operation include {first energy storage sub-module SM1, second energy storage sub-module SM2, third energy storage sub-module SM3, fourth energy storage sub-module SM4}, if Δn is determined to be 1, and the sorting result of the 4 energy storage sub-modules that have been put into operation is {first energy storage sub-module SM1, second energy storage sub-module SM2, third energy storage sub-module SM3, fourth energy storage sub-module SM4}, then the above-mentioned fourth energy storage sub-module SM4 can be determined as the target cut-out sub-module.

[0155] S24: If the switching times of the target switching submodule is less than the switching times threshold, a switching operation is performed on the target switching submodule.

[0156] In a specific application, the switching times threshold may be determined based on a transient thermal resistance curve and a steady-state junction temperature upper limit of a power device of the energy storage submodule.

[0157] In specific applications, simulation can be performed based on the transient thermal resistance curve and equivalent thermal model of the power device in the energy storage submodule to obtain the relationship between the switching number threshold and the upper limit of the steady-state junction temperature. The service life is related to temperature. After considering the service life and margin of the device, the switching number threshold can be determined. For example, the service life requires at least 35 years of operation. After considering the margin, the service life is determined to be 40 years. Based on the above 40-year life defect, the upper limit of the steady-state junction temperature can be obtained, and the switching number threshold can be further reversed through simulation.

[0158] It should be noted that the pause thermal resistance curve and the upper limit of steady-state junction temperature of the above-mentioned power devices are fixed parameters of the devices. By referring to the factory description documents of the devices, it can be known that the pause thermal resistance curve and the upper limit of steady-state junction temperature of power devices of the same specification produced by the same manufacturer are consistent.

[0159] In a specific application, the energy storage valve controller can obtain the switching times of the target switching submodule in the current control cycle (i.e., the sum of the switching times of the target switching submodule in the current control cycle), and then determine whether the switching times of the above target switching submodule is less than the switching times threshold. If the switching times of the target switching submodule is less than the switching times threshold, it means that the switching times of the target switching submodule in the current control cycle is still within an acceptable range. Therefore, the switching operation of the target switching submodule can continue.

[0160] In a specific application, if the target switching submodule determined in S23 is the target input submodule, and the switching times of the target input submodule is less than the switching times threshold, the energy storage valve controller may modulate the target input submodule.

[0161] In a specific application, the specific description of the energy storage valve controller modulating the target input submodule can be found in the relevant description of S143, which will not be elaborated here.

[0162] In a specific application, if the target switching submodule determined in S23 is a target switching-out submodule, and the switching times of the target switching-out submodule is less than the switching times threshold, the energy storage valve controller may modulate the target switching-out submodule.

[0163] In a specific application, for a specific description of the energy storage valve controller modulating the target cut-out submodule, reference may be made to the relevant description of S13, which will not be elaborated herein.

[0164] In the embodiment of the present application, the target switching submodule is first determined by means of priority balancing, and the switching operation is performed on the target switching submodule only when the switching times of the target switching submodule is less than the switching times threshold. The switching times of the energy storage submodule can be limited while ensuring balance, thereby reducing the average switching frequency and loss of the energy storage submodule and increasing the service life of the energy storage system.

[0165] See also Fig.12 Based on this, in an embodiment of the present application, the above-mentioned equalization method may further include the following steps:

[0166] S25: If the switching times of the target switching submodule is greater than or equal to the switching times threshold, the target switching submodule is kept in a switched-out state, and the target switching submodule is controlled to exit the switching queue.

[0167] In a specific application, controlling the target switching submodule to exit the switching queue means that the target energy storage submodule exits the energy storage submodule for priority sorting.

[0168] Exemplarily, assume that the energy storage system includes 8 energy storage sub-modules, among which the energy storage sub-modules that have been put into operation include {first energy storage sub-module SM1, second energy storage sub-module SM2, third energy storage sub-module SM3, fourth energy storage sub-module SM4}. If the current control cycle requires the investment of one energy storage sub-module, assume that the remaining 4 energy storage sub-modules are sorted according to priority and the sorting results obtained are {fifth energy storage sub-module SM5, sixth energy storage sub-module SM6, seventh energy storage sub-module SM7, eighth energy storage sub-module SM8}, then the fifth energy storage sub-module SM5 can be determined as the target investment sub-module. If the switching times of the fifth energy storage sub-module SM5 is greater than or equal to the switching times threshold, the controller will delete the fifth energy storage sub-module SM5 from the sorting results {fifth energy storage sub-module SM5, sixth energy storage sub-module SM6, seventh energy storage sub-module SM7, eighth energy storage sub-module SM8}, and the remaining sorting results are {sixth energy storage sub-module SM6, seventh energy storage sub-module SM7, eighth energy storage sub-module SM8}.

[0169] In an embodiment of the present application, in order to reduce the possibility of damage to the energy storage submodule, the above-mentioned keeping the target switching submodule in a switched-out state and controlling the target switching submodule to exit the switching queue can specifically be keeping the target switching submodule in a switched-out state within a thermal stabilization time and controlling the target switching submodule to exit the switching queue.

[0170] In the embodiment of the present application, since the switching times of the target switching submodule is greater than the switching times threshold, if the switching operation continues to be performed, it may cause damage to the energy storage submodule. Therefore, after determining that the switching times of the target switching submodule is greater than or equal to the switching times threshold, it is necessary to control the target switching submodule to exit the switching queue, so that the energy storage valve controller will not sort the target switching submodule when sorting the energy storage submodules, that is, the sorting result obtained in this way will not include the above-mentioned target switching submodule, so that the judgment steps for the same energy storage submodule that has exceeded the switching times threshold can be reduced, and the loss of computing resources of the controller can be reduced.

[0171] In an embodiment of the present application, after the above S25, the following steps may be further included:

[0172] The target switching submodule is re-determined according to the updated sorting result.

[0173] In the embodiment of the present application, after the energy storage submodules exceeding the switching number threshold are withdrawn from the switching queue, an updated sorting result can be obtained, so that Δn energy storage submodules can be determined as target switching submodules according to the updated sorting result.

[0174] In an embodiment of the present application, the above-mentioned equalization method may further include the following steps:

[0175] When the next calculation cycle starts, the switching times of each energy storage submodule in the energy storage system are reset, and the ranking results of each energy storage submodule in the energy storage system are reacquired.

[0176] In the embodiment of the present application, the above calculation period can be set according to the thermal stabilization time of the power devices of each energy storage sub-module.

[0177] In the embodiment of the present application, the calculation cycle is greater than the control cycle, that is, the calculation cycle may be an integer multiple of the control cycle, that is, one calculation cycle may include multiple control cycles.

[0178] For example, the calculation period may be 1 second, and the control period may be 50 seconds. μs .

[0179] It can be seen from the above that at the beginning of the next calculation cycle, all energy storage sub-modules are put back into order, and the switching times of each energy storage sub-module in the energy storage system are reset, so that each energy storage sub-module in the energy storage system can be switched again according to the balancing demand, and the switching times of the energy storage sub-modules in the energy storage system can be ensured not to exceed the switching times threshold, thereby protecting the energy storage sub-modules. While achieving balancing, the loss of the energy storage sub-modules is controlled within an acceptable range, thereby extending the service life of the energy storage system.

[0180] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0181] like Fig.13 As shown, another embodiment of the present application further provides an equalization device 13 , which includes: an acquisition module 131 , a determination module 132 and a rotation switching module 133 .

[0182] The acquisition module 131 is used to acquire the input quantity of the current control cycle and the input quantity of the previous control cycle.

[0183] The determination module 132 is used to determine the switching state of the energy storage system according to the input quantity of the current control cycle and the input quantity of the previous control cycle.

[0184] The rotation switching module 133 is used to determine the target switching submodule according to the rotation switching mode if the switching state of the energy storage system is the switching state, and control the target switching submodule to be switched out from the energy storage system.

[0185] In an embodiment of the present application, the balancing device 13 further includes a balancing input module.

[0186] The balanced input module is used to determine the target input submodule according to the balanced priority method if the switching state of the energy storage system is the input state, and control the target input submodule to be input into the energy storage system.

[0187] In one embodiment of the present application, the balanced input module includes a sorting unit, a first determining unit and a first modulating unit.

[0188] The sorting unit is used to sort the target parameters of all energy storage submodules in descending order according to their priorities to obtain a sorting result.

[0189] The first determination unit is used to determine the first |Δn| switched-out energy storage submodules of the sorting result as target input submodules, wherein Δn is the difference between the input quantity of the current control cycle and the input quantity of the previous control cycle.

[0190] The first modulation unit is used to modulate the target input submodule.

[0191] In an embodiment of the present application, the determination module 132 includes a calculation unit and a state determination unit.

[0192] The calculation unit is used to calculate the difference between the input quantity of the current control cycle and the input quantity of the previous control cycle to obtain the submodule change amount.

[0193] The state determination unit is used to determine that the switching state of the energy storage system is an input state if the submodule change amount is greater than 0; and to determine that the switching state of the energy storage system is a cut-out state if the submodule change amount is less than 0.

[0194] In one embodiment of the application, the balancing device 13 further includes a maintaining module, and the maintaining module is used to maintain the state of each energy storage sub-module of the energy storage system unchanged if the switching state of the energy storage system is unchanged.

[0195] In an embodiment of the present application, the above-mentioned balancing device 13 further includes a target switching determination module and an execution module. Among them:

[0196] The target switching determination module is used to determine the target switching submodule according to the submodule variation and the switching state of the energy storage system in a balanced priority manner.

[0197] The execution module is used to execute a switching operation on the target switching submodule if the switching times of the target switching submodule is less than the switching times threshold.

[0198] In one embodiment of the present application, the balancing device 13 further includes an exit module.

[0199] The exit module is used to keep the target switching submodule in a switched-out state and control the target switching submodule to exit the switching queue if the switching times of the target switching submodule is greater than or equal to the switching times threshold.

[0200] In an embodiment of the present application, the exit module is specifically used to maintain the switched-out state of the target switching submodule within the thermal stabilization time, and control the target switching submodule to exit the switching queue.

[0201] In one embodiment of the present application, the target switching determination module includes a sorting unit, a balanced input determination unit and a balanced switching determination unit.

[0202] The sorting unit is used to sort the target parameters of all energy storage submodules in descending order according to their priorities to obtain a sorting result.

[0203] The balanced input determination unit is used to determine the first |Δn| switched-out energy storage submodules of the sorting result as target input submodules, wherein Δn is the difference between the input quantity of the current control cycle and the input quantity of the previous control cycle.

[0204] The balanced switching determination unit is used to determine the last |Δn| put-in-service energy storage submodules of the sorting result as target switching-out submodules, wherein Δn is the difference between the put-in-service quantity in the current control cycle and the put-in-service quantity in the previous control cycle.

[0205] In an embodiment of the present application, the target switching determination module is further configured to re-determine the target switching sub-module according to the updated sorting result.

[0206] In an embodiment of the present application, the equalization device 13 further includes a reset module.

[0207] The reset module is used to reset the switching times of each energy storage submodule in the energy storage system and re-acquire the ranking results of each energy storage submodule in the energy storage system when the next calculation cycle starts.

[0208] In an embodiment of the present application, the above-mentioned balancing device 13 may further include a switching times determining module.

[0209] The switching times determination module is used to determine the switching times threshold value according to the transient thermal resistance curve and the upper limit of the steady-state junction temperature of the power device of the energy storage submodule.

[0210] Another embodiment of the present application further provides a terminal device, which may be a storage valve controller. The terminal device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the program to implement the balancing method of any of the above-mentioned embodiments.

[0211] For example, Fig.14 Schematic diagram of a terminal device provided by an embodiment of the present application. Fig.14 As shown, the terminal device 14 provided in this embodiment includes: a processor 140, a memory 141, and a computer program 142 stored in the memory 141 and executable on the processor 140. When the processor 140 executes the computer program 142, the steps in the above-mentioned various equalization method embodiments are implemented, for example Figure 6 S11 to S13 shown.

[0212] Exemplarily, the computer program 142 may be divided into one or more modules / units, which are stored in the memory 141 and executed by the processor 140 to complete the present application. The one or more modules / units may be a series of computer program instruction segments that can complete specific functions, and the instruction segments are used to describe the execution process of the computer program 142 in the terminal device 14. For example, the computer program 142 may be divided into multiple units, and the specific functions of each unit may be described in detail in the following table. Fig.14 The relevant descriptions in the corresponding embodiments are not repeated here.

[0213] The terminal device may include, but is not limited to, a processor 140 and a memory 141. Those skilled in the art will appreciate that Fig.14 It is only an example of the terminal device 14 and does not constitute a limitation of the terminal device 14. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the terminal device may also include input and output devices, network access devices, buses, etc.

[0214] The processor 140 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0215] The memory 141 may be an internal storage unit of the terminal device 14, such as a hard disk or memory of the terminal device 11. The memory 141 may also be an external storage device of the terminal device 14, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the terminal device 21. Further, the memory 141 may also include both an internal storage unit and an external storage device of the terminal device 14. The memory 141 is used to store the computer program and other programs and data required by the terminal device. The memory 141 may also be used to temporarily store data that has been output or is to be output.

[0216] The terminal device provided in the embodiment of the present application and the method provided in the embodiment of the present application are based on the same inventive concept and have the same beneficial effects as the method adopted, operated or implemented by them.

[0217] Another embodiment of the present application provides an energy storage system, including the terminal device provided in the above embodiment. The energy storage system may also include an energy storage submodule, and the above terminal device executes the balancing method provided in the embodiment of the present application to achieve balancing of the energy storage submodule.

[0218] The embodiment of the present application further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the balancing method in the above method embodiment can be implemented.

[0219] Examples of computer-readable storage media may include, but are not limited to, optical disks, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory, or other optical or magnetic storage media, which are not listed here one by one.

[0220] The embodiment of the present application provides a computer program product. When the computer program product runs on a terminal device, the terminal device can implement the above-mentioned balancing method when executing the computer program product.

[0221] The computer-readable storage medium and computer program product provided in the embodiments of the present application are based on the same inventive concept as the method provided in the embodiments of the present application, and have the same beneficial effects as the method adopted, run or implemented by them.

[0222] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the terminal device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0223] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0224] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0225] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A balancing method, characterized in that: include: Get the input quantity of the current control cycle and the input quantity of the previous control cycle; Determine the switching state of the energy storage system according to the input quantity of the current control cycle and the input quantity of the previous control cycle; If the switching state of the energy storage system is a cut-out state, a target cut-out submodule is determined according to a cut-out method in turn, and the target cut-out submodule is controlled to be cut out from the energy storage system.

2. The equalization method according to claim 1, characterized in that: If the switching state of the energy storage system is the switching-out state, then after determining the target switching-out submodule according to the switching-out mode in turn, and controlling the target switching-out submodule to be switched out from the energy storage system, the method further includes: If the switching state of the energy storage system is the on-state, a target on-sub module is determined according to a balance priority method, and the target on-sub module is controlled to be put into the energy storage system.

3. The equalization method according to claim 2, characterized in that: If the switching state of the energy storage system is the input state, a target input submodule is determined according to a balanced priority method, and the target input submodule is controlled to be input into the energy storage system, including: Sorting the target parameters of all energy storage submodules in descending order according to their priorities to obtain a sorting result; Determine the first |Δn| energy storage submodules of the sorting result as target input submodules, where Δn is the difference between the input quantity of the current control cycle and the input quantity of the previous control cycle; The target input submodule is modulated.

4. The equalization method according to claim 2 or 3, characterized in that: The determining the switching state of the energy storage system according to the input quantity of the current control cycle and the input quantity of the previous control cycle includes: Calculate the difference between the input quantity of the current control cycle and the input quantity of the previous control cycle to obtain the submodule change amount; If the submodule change amount is greater than 0, determining that the switching state of the energy storage system is the switched-on state; If the submodule variation is less than 0, it is determined that the switching state of the energy storage system is a switching-out state.

5. The equalization method according to any one of claims 1 to 4, characterized in that: The switching state of the energy storage system also includes an unchanged state, and the balancing method further includes: If the switching state of the energy storage system is unchanged, the states of the energy storage submodules of the energy storage system are maintained unchanged.

6. A balancing method, characterized in that: include: Get the input quantity of the current control cycle and the input quantity of the previous control cycle; Determine the submodule change amount and the switching state of the energy storage system according to the input quantity of the current control cycle and the input quantity of the previous control cycle; According to the submodule variation and the switching state of the energy storage system, a target switching submodule is determined in a balanced priority manner; If the switching times of the target switching submodule is less than the switching times threshold, a switching operation is performed on the target switching submodule.

7. The equalization method according to claim 6, characterized in that: When the switching state of the energy storage system is in the on state, determining the target switching submodule in a balanced priority manner according to the submodule variation and the switching state of the energy storage system includes: Sorting the target parameters of all the switched-out energy storage submodules in descending order according to their priorities to obtain a sorting result; The first |Δn| switched-out energy storage submodules in the sorting result are determined as target input submodules, wherein Δn is the difference between the input quantity in the current control cycle and the input quantity in the previous control cycle.

8. The equalization method according to claim 6, characterized in that: When the switching state of the energy storage system is the cut-out state, determining the target switching submodule in a balanced priority manner according to the submodule variation and the switching state of the energy storage system includes: Sorting the target parameters of all the energy storage submodules that have been put into use in descending order according to their priorities to obtain a sorting result; The last |Δn| put-in-service energy storage submodules of the sorting result are determined as target cut-out submodules, wherein Δn is the difference between the put-in-service quantity in the current control cycle and the put-in-service quantity in the previous control cycle.

9. The equalization method according to any one of claims 6 to 8, characterized in that: After determining the target switching submodule according to the balance priority method based on the submodule variation and the switching state of the energy storage system, the method further includes: If the switching times of the target switching submodule is greater than or equal to the switching times threshold, the target switching submodule is kept in a switched-out state, and the target switching submodule is controlled to exit the switching queue.

10. The equalization method according to claim 9, characterized in that: If the switching times of the target switching submodule is greater than or equal to the switching times threshold, the target switching submodule is kept in a switched-out state, and the target switching submodule is controlled to exit the switching queue, including: The target switching submodule is kept in a switched-out state within the thermal stabilization time, and the target switching submodule is controlled to exit the switching queue.

11. The equalization method according to claim 9 or 10, characterized in that: After the target switching submodule is kept in a switched-out state if the switching number of the target switching submodule is greater than or equal to the switching number threshold, and the target switching submodule is controlled to exit the switching queue, the method further includes: The target switching submodule is re-determined according to the updated sorting result.

12. The equalization method according to any one of claims 6 to 11, characterized in that: The balancing method further comprises: When the next calculation cycle starts, the switching times of each energy storage submodule in the energy storage system are reset, and the ranking results of each energy storage submodule in the energy storage system are reacquired.

13. The equalization method according to any one of claims 6 to 12, characterized in that: The balancing method further comprises: The switching times threshold is determined according to a transient thermal resistance curve and a steady-state junction temperature upper limit of a power device of the energy storage submodule.

14. A terminal device, characterized in that: The invention comprises 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 equalization method according to any one of claims 1 to 5 or the equalization method according to any one of claims 6 to 13 is implemented.

15. An energy storage system, characterized in that: It comprises a plurality of energy storage submodules and the terminal device as claimed in claim 14.

16. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the equalization method according to any one of claims 1 to 5 or the equalization method according to any one of claims 6 to 13 is implemented.

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