A method of controlling an energy storage system

Abstract

This application provides a control method for an energy storage system, comprising: determining the state parameters corresponding to each individual battery cell; determining a multi-dimensional control factor corresponding to each individual battery cell based on different state dimensions indicated by the state parameters at preset calculation cycles; sorting multiple individual batteries cells according to the charge / discharge state of the energy storage system and the multi-dimensional control factor; determining the output demand voltage corresponding to the energy storage system based on the peak reference voltage and AC frequency corresponding to the energy storage system; and controlling the access state of each individual battery cell in the next AC cycle by applying the nearest level approximation method based on the sorting result, the output demand voltage, and the maximum supply voltage corresponding to each individual battery cell in the next AC cycle. This application controls the energy storage units connected to the charge / discharge circuit of the energy storage system and their access time through multi-dimensional control factors calculated from multiple dimensions, thereby achieving full utilization of the energy of the energy storage units.

Description

Technical Field

[0001] This application relates to the field of dynamic reconfigurable battery energy storage control technology, and in particular to an energy storage system control method. Background Technology

[0002] Dynamically reconfigurable battery energy storage technology based on energy digitization changes the fixed series-parallel connection method of batteries in traditional energy storage systems. By connecting a control unit in parallel on the battery side to control the time when the battery is connected to the charging and discharging circuit, the battery energy is made "fully utilized" and the battery safety is guaranteed. It fundamentally solves the safety and economic problems of energy storage systems. Dynamically reconfigurable battery energy storage technology accepts inconsistencies in battery production and composition, and ensures full utilization of battery energy by optimizing battery use.

[0003] Currently, the battery optimization algorithms for dynamically reconfigurable battery energy storage technology based on energy digitization are relatively simple, generally based on parameters such as battery state of charge and battery voltage. However, due to the inconsistency of individual cells, the state of charge, health, energy state, temperature, and other state parameters of individual cells will vary greatly during use. Even when the energy storage system accepts batteries of different types, capacities, manufacturers, and batches, the access control of each individual cell in the energy storage system unit is only based on basic parameters such as battery state of charge and battery voltage. These methods cannot effectively distinguish and control the characteristics of different batteries, and cannot make full use of the energy of all batteries, resulting in limited overall performance of the energy storage system. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide at least one energy storage system control method, which controls the energy storage units connected to the charging and discharging circuit of the energy storage system and their connection time by using multi-dimensional control factors calculated from multiple dimensions, so as to achieve full utilization of the energy of the energy storage units.

[0005] This application mainly includes the following aspects:

[0006] In a first aspect, embodiments of this application provide an energy storage system including multiple energy storage units and an energy storage controller. Each energy storage unit includes a single battery cell. A method is applied to the energy storage controller, comprising: determining state parameters corresponding to each single battery cell; determining a multi-dimensional control factor corresponding to each single battery cell based on different state dimensions indicated by the state parameters at preset calculation cycles; sorting the multiple single batteries cells according to the charge / discharge state of the energy storage system and the multi-dimensional control factor; determining the output demand voltage of the energy storage system according to the peak reference voltage and AC frequency corresponding to the energy storage system; and controlling the access state of each single battery cell in the next AC cycle by applying the nearest-level approximation method based on the sorting result, the output demand voltage, and the maximum supply voltage of each single battery cell in the next AC cycle.

[0007] In one possible implementation, the state parameters include state of charge, state of health, state of energy, state of power, and battery temperature. The multidimensional control factors are determined as follows: based on the state parameters corresponding to each individual cell, a state of health consistency control factor, a state of energy consistency control factor, a state of power consistency control factor, a temperature control factor, and a temperature consistency control factor are determined for each individual cell; the state of health consistency control factor, state of energy consistency control factor, state of power consistency control factor, temperature control factor, and temperature consistency control factor are weighted and calculated to determine the multidimensional control factors corresponding to each individual cell.

[0008] In one possible implementation, the health state consistency control factor is determined by: determining the maximum health state value corresponding to all individual cells in the energy storage system; calculating the relative difference in health state between the health state corresponding to the individual cell and the maximum health state value; and determining the square of the relative difference in health state as the health state consistency control factor.

[0009] In one possible implementation, the energy state consistency control factor is determined by: using the state of charge, state of health, and rated energy of the individual cells to determine the available energy of each individual cell; and calculating the energy state consistency control factor from the perspective of battery energy state based on the available energy of the individual cells and the charge / discharge state of the energy storage system.

[0010] In one possible implementation, the available energy includes rechargeable energy, wherein the energy state consistency control factor is determined by: if the charge / discharge state is the charging state, then determining the rechargeable energy corresponding to a single cell and the maximum rechargeable energy corresponding to all single cells based on the state of charge, state of health, and rated energy; calculating the relative difference in rechargeable energy between the rechargeable energy corresponding to a single cell and the maximum rechargeable energy; and determining the square of the relative difference in rechargeable energy as the energy state consistency control factor.

[0011] In one possible implementation, the available energy includes releasable energy, wherein the energy state consistency control factor is determined as follows: if the charge / discharge state corresponding to the energy storage system is the discharge state, then the releasable energy corresponding to a single cell and the maximum releasable energy corresponding to all single cells are determined according to the state of charge, state of health, and rated energy; the relative difference in releasable energy between the releasable energy corresponding to a single cell and the maximum releasable energy is calculated; and the square of the relative difference in releasable energy is determined as the energy state consistency control factor.

[0012] In one possible implementation, the power state consistency control factor is determined by: determining the maximum power state value corresponding to all individual cells; calculating the relative power state difference between the power state corresponding to each individual cell and the maximum power state value; and determining the power state consistency control factor by squaring the relative power state difference.

[0013] In one possible implementation, the temperature consistency control factor for a single cell is calculated as follows: the temperature control factor for a single cell is determined based on the battery temperature and the relationship function between the battery temperature and the temperature control factor.

[0014] In one possible implementation, when the battery temperature corresponding to a single cell is greater than or equal to the maximum battery application temperature or less than or equal to the minimum battery application temperature, the temperature control factor is 1; when the battery temperature corresponding to a single cell is at the optimal battery application temperature, the temperature control factor is 0. The relationship function is determined by constructing a relationship function through linear interpolation based on the minimum battery application temperature, the maximum battery application temperature, and the temperature control factor corresponding to the optimal battery temperature.

[0015] In one possible implementation, the temperature consistency control factor for a single cell is calculated using the following formula: calculate the average temperature of all single cells; calculate the relative temperature difference between the cell temperature and the average temperature of all single cells; and determine the square of the relative temperature difference as the temperature consistency control factor for the single cell.

[0016] In one possible implementation, the multidimensional control factor is determined using the following formula:

[0017] K=k1×kbh+k2×kbe+k3×kbp+k4×kbtem+k5×kbtem_ave

[0018] In this formula, k1 represents the first given weight corresponding to the health state consistency control factor kbh, k2 represents the second given weight corresponding to the energy state consistency control factor kbe, k3 represents the third given weight corresponding to the power state consistency control factor kbp, k4 represents the fourth given weight corresponding to the temperature control factor kbtem, and k5 represents the fifth given weight corresponding to the temperature consistency control factor kbtem_ave. k1+k2+k3+k4+k5=1.

[0019] In one possible implementation, the method further includes: determining whether there is redundant design in the individual cells of the energy storage system; if there is redundant design in the energy storage system, then all individual cells in the energy storage system are identified as candidate individual cells; if there is no redundant design in the energy storage system, then the difference between the multidimensional control factor corresponding to each individual cell and the minimum multidimensional control factor corresponding to each individual cell is calculated; for each individual cell, the difference value corresponding to the individual cell is compared with a preset control factor limit; if the difference value corresponding to the individual cell is greater than the preset control factor limit, then the individual cell is identified as an unusable cell and bypassed; if the difference value corresponding to the individual cell is less than or equal to the preset control factor limit, then the individual cell is identified as a candidate individual cell; within a preset calculation cycle, based on the sorting results, the output demand voltage, and the maximum supply voltage corresponding to each candidate individual cell in the next AC cycle, the nearest level approximation method is applied to determine the operation mode of each candidate individual cell in the next AC cycle.

[0020] In one possible implementation, the AC cycle includes an output voltage rise phase, wherein the operation mode of each individual cell during the output voltage rise phase is determined by: for each moment of the output voltage rise phase: determining the individual cell sequence and the corresponding connected voltage at that moment, the individual cell sequence including multiple individual cells arranged according to a sorting result, the connected voltage being the sum of the maximum supply voltages corresponding to the connected individual cells; comparing the output demand voltage with the connected voltage at that moment to determine the comparison result; and selecting, based on the comparison result, the individual cell sequence, and the maximum supply voltage corresponding to each individual cell, the individual cell that performs the target conduction operation at that moment from the individual cell sequence.

[0021] In one possible implementation, the output voltage rising phase includes a forward output voltage rising phase and a reverse output voltage rising phase. The conduction action includes a forward conduction action corresponding to the forward output voltage rising phase and a reverse conduction action corresponding to the reverse output voltage rising phase. The method further includes: for the forward output voltage rising phase, the target conduction action is a forward conduction action; for the reverse output voltage rising phase, the target conduction action is a reverse conduction action.

[0022] In one possible implementation, the individual battery that performs the target conduction action at each moment during the output voltage rise phase is determined as follows: if the output demand voltage is greater than or equal to the total connected voltage at that moment, then a single battery is selected sequentially from the unconnected individual batteries in the individual battery sequence, and the selected individual battery is the single battery with the smallest multidimensional control factor among the unconnected individual batteries; the selected individual battery is determined as the connected battery that performs the target conduction action at that moment, and the connection status of the selected individual battery is updated to connected; if the output demand voltage is less than the total connected voltage, then it is determined that no battery connection is performed at that moment.

[0023] In one possible implementation, the AC cycle further includes an output voltage drop phase, wherein the action mode of each individual cell in the output voltage drop phase of the next AC cycle is determined by: determining a battery access sequence, which includes multiple access cells sorted in ascending order according to a multidimensional control factor; performing a battery cut-off determination process on the battery access sequence for each moment of the output voltage drop phase; and determining the action mode corresponding to the multiple access cells based on the battery cut-off processing result at each moment.

[0024] 1. In one possible implementation, the battery cut-off determination process includes: summing the maximum supply voltages of the remaining access batteries in the battery access sequence (excluding the battery to be operated), determining the summation result, wherein the battery to be operated is the access battery located at the end of the battery access sequence; comparing the summation result with the output demand voltage corresponding to that moment; if the summation result is less than or equal to the output demand voltage corresponding to that moment, determining that the target bypass action is to be performed on the battery to be operated at that moment; deleting the battery to be operated from the battery access sequence; if the summation result is greater than the output demand voltage corresponding to that moment, returning to execute the battery cut-off determination process for the next moment.

[0025] In one possible implementation, the output voltage drop phase includes a forward output voltage drop phase and a reverse output voltage drop phase. The conduction action includes a forward bypass action corresponding to the forward output voltage drop phase and a reverse bypass action corresponding to the reverse output voltage drop phase. The method further includes: for the forward output voltage drop phase, the target bypass action is a forward bypass action; for the reverse output voltage drop phase, the target bypass action is a reverse bypass action.

[0026] This application provides an energy storage system control method, comprising: determining the state parameters corresponding to each individual battery cell; determining a multi-dimensional control factor corresponding to each individual battery cell based on the different state dimensions indicated by the state parameters corresponding to the individual battery cell at preset calculation cycles; sorting multiple individual batteries cells according to the charge / discharge state of the energy storage system and the multi-dimensional control factor; determining the output demand voltage corresponding to the energy storage system according to the peak reference voltage and AC frequency corresponding to the energy storage system; and controlling the access state of each individual battery cell in the next AC cycle by applying the nearest level approximation method based on the sorting result, the output demand voltage, and the maximum supply voltage corresponding to each individual battery cell in the next AC cycle.

[0027] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic diagram of the structure of an energy storage system provided in an embodiment of this application is shown;

[0030] Figure 2 A flowchart of an energy storage system control method provided in an embodiment of this application is shown;

[0031] Figure 3 A flowchart illustrating a method for determining multidimensional control factors according to an embodiment of this application is shown;

[0032] Figure 4 This illustration shows a schematic diagram of a multidimensional control factor determination factor provided in an embodiment of this application;

[0033] Figure 5This illustration shows a schematic diagram of the relationship function between battery temperature and temperature control factor provided in an embodiment of this application;

[0034] Figure 6 This illustration shows a schematic diagram of the output demand voltage of an energy storage system according to an embodiment of this application;

[0035] Figure 7 This paper shows a functional block diagram of a control device for an energy storage system provided in an embodiment of this application;

[0036] Figure 8 A schematic diagram of the structure of an electronic device provided in an embodiment of this application is shown. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the drawings in this application are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of this application. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0038] Furthermore, the described embodiments are merely some, not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0039] Dynamically reconfigurable battery energy storage technology based on energy digitization changes the fixed series-parallel connection method of batteries in traditional energy storage systems. By connecting a control unit in parallel on the battery side to control the time when the battery is connected to the charging and discharging circuit, the battery energy is made "fully utilized" and the battery safety is guaranteed. It fundamentally solves the safety and economic problems of energy storage systems. Dynamically reconfigurable battery energy storage technology accepts inconsistencies in battery production and composition, and ensures full utilization of battery energy by optimizing battery use.

[0040] Currently, the battery optimization algorithms for dynamically reconfigurable battery energy storage technology based on energy digitization are relatively simple, generally based on parameters such as battery state of charge and battery voltage. However, due to the inconsistency of individual cells, the state of charge, health, energy state, temperature, and other state parameters of individual cells will vary greatly during use. Even when the energy storage system accepts batteries of different types, capacities, manufacturers, and batches, it can only control the access of each individual cell in the energy storage system unit based on basic parameters such as battery state of charge and battery voltage, which cannot make full use of the energy of all batteries.

[0041] Based on this, this application provides an energy storage system control method. By using multi-dimensional control factors calculated from multiple dimensions, the method controls the energy storage units connected to the charging and discharging circuit of the energy storage system and their connection time, thereby achieving full utilization of the energy of the energy storage units. Specifically, the method is as follows:

[0042] Please see Figure 1 , Figure 1 A schematic diagram of the structure of an energy storage system provided in an embodiment of this application is shown. Figure 1 The diagram illustrates a three-phase energy storage system. Each phase of the three-phase energy storage system (including phase A, phase B, and phase C) includes multiple energy storage units and an energy storage controller (not shown in the diagram). Each energy storage unit includes at least one single battery cell, and each energy storage unit is connected to a corresponding control module. The control module can be an H-bridge circuit, and all control modules are connected to the energy storage controller.

[0043] Please see Figure 2 , Figure 2 A flowchart illustrating a control method for an energy storage system provided in an embodiment of this application is shown. Figure 2 As shown in the embodiments of this application, the method provided is applied to an energy storage controller and includes the following steps:

[0044] S100. Determine the state parameters corresponding to each individual cell.

[0045] S200. Every preset calculation cycle, for each individual cell, determine the multi-dimensional control factor corresponding to that individual cell based on the different state dimensions indicated by the state parameters corresponding to that individual cell.

[0046] S300 sorts multiple individual cells according to the charge / discharge state of the energy storage system and multi-dimensional control factors.

[0047] S400. Determine the required output voltage of the energy storage system based on the peak reference voltage and AC frequency corresponding to the energy storage system.

[0048] S500: Based on the sorting results, the output required voltage, and the maximum supply voltage of each individual cell in the next AC cycle, the nearest level approximation method is applied to control the connection status of each individual cell in the next AC cycle.

[0049] In step S100, this application collects the corresponding operating data of each individual battery in the energy storage system through the control module corresponding to each individual battery. The operating data includes, but is not limited to, at least one of the following: battery voltage, battery current, and battery temperature. Further, according to the type of the individual battery, the corresponding state estimation algorithm is selected to calculate the operating data of the individual battery to determine the state parameters of the individual battery. The state parameters include the state of charge (SOC), state of health (SOH), state of energy (SOE), state of power (SOP), and battery temperature (T).

[0050] In step S200, the state parameters indicate different state dimensions. Specifically, these different state dimensions include state of charge, state of health, state of energy, state of power, battery temperature, and average battery temperature. Please refer to [link to relevant documentation]. Figure 3 , Figure 3 This diagram illustrates a method for determining multidimensional control factors according to an embodiment of this application. Figure 3 As shown, this application calculates the multidimensional control factor for each individual cell from five perspectives: State of Health (SOH), State of Charge (SOC), State of Energy (SOE), State of Power (SOP), Battery Temperature (T), and Battery Average Temperature (Tave). The multidimensional control factor describes the consistency of the individual cell in the dimensions of State of Charge, State of Health, State of Energy, State of Power, Battery Temperature, and Battery Average Temperature. For each individual cell, the smaller the multidimensional control factor, the better the consistency between the individual cell and other individual cells in the energy storage system, and the lower the difference.

[0051] In step S300, since the multidimensional control factor reflects the consistency between a single cell and other single cells in the energy storage system, this application can use the multidimensional control factor to sort multiple single cells from small to large to determine the sequence of single cells that can reflect the consistency.

[0052] In step S400, the peak reference voltage V corresponding to the energy storage system can be calculated using a preset power control algorithm. rms And the AC frequency Freq, further, the corresponding output voltage requirement of the energy storage system. Where w = 2πFreq, and t represents the time period. Indicates phase, initial phase

[0053] In step S500, the nearest battery approximation method is used, combined with the sorting results, the output demand voltage, and the pre-obtained maximum supply voltage of each individual battery in the next AC cycle, to determine the on / off control mode of each individual battery in the next AC cycle.

[0054] In steps S100 to S500, this application provides an energy storage system control method, which mainly calculates the multi-dimensional control factor corresponding to each individual battery from the perspectives of the state of health (SOH), state of energy (SOE), state of power (SOP), state of charge (SOC), battery temperature (T), and average battery temperature (Tave) of the individual battery. Based on the multi-dimensional control factor, the method of connecting the individual battery to the charging and discharging circuit of the energy storage system is controlled, thereby realizing the full utilization of the energy of each individual battery.

[0055] In a preferred embodiment, please refer to Figure 4 , Figure 4 A flowchart illustrating a method for determining multidimensional control factors according to an embodiment of this application is shown. Figure 4 As shown, step S200 includes:

[0056] S2001. Based on the state parameters corresponding to each individual cell, determine the health state consistency control factor, energy state consistency control factor, power state consistency control factor, temperature control factor, and temperature consistency control factor corresponding to each individual cell.

[0057] S2002, Perform weighted calculations on the health state consistency control factor, energy state consistency control factor, power state consistency control factor, temperature control factor, and temperature consistency control factor to determine the multidimensional control factor corresponding to each individual cell.

[0058] In step S2002, the multidimensional control factor is determined using the following formula:

[0059] K=k1×kbh+k2×kbe+k3×kbp+k4×kbtem+k5×kbtem_ave

[0060] In this formula, k1 represents the first given weight corresponding to the health state consistency control factor kbh, k2 represents the second given weight corresponding to the energy state consistency control factor kbe, k3 represents the third given weight corresponding to the power state consistency control factor kbp, k4 represents the fourth given weight corresponding to the temperature control factor kbtem, and k5 represents the fifth given weight corresponding to the temperature consistency control factor kbtem_ave. k1+k2+k3+k4+k5=1.

[0061] In a preferred embodiment, in step S2001, the health status consistency control factor is determined in the following manner:

[0062] Determine the maximum health state value for all individual cells in the energy storage system, calculate the relative health state difference between the health state value of each individual cell and the maximum health state value, and determine the square of the relative health state difference as the health state consistency control factor.

[0063] In one specific embodiment, the on / off control method of a single battery is considered from the perspective of battery health status. The principle followed is to prioritize the use of single batteries with higher health status (SOH) to enhance the consistency of battery health status. Therefore, the maximum health status value (SOHmax) corresponding to all single batteries is first determined. Then, the relative difference between the health status SOH of a single battery and the maximum health status value (SOHmax) is calculated. The square of the relative difference is determined as the health status consistency factor (kbh) of the single battery. The smaller the health status consistency factor (kbh), the higher the priority of the single battery.

[0064] In one specific embodiment, in step S2001, the health state consistency factor kbh corresponding to a single cell is determined by the following formula:

[0065] kbh = [(SOH - SOHmax) / SOHmax] 2

[0066] In a preferred embodiment, in step S2001, the energy state consistency control factor is determined in the following manner:

[0067] By utilizing the state of charge, state of health, and rated energy of individual cells, the available energy of individual cells is determined. Based on the available energy of individual cells and the charge / discharge state of the energy storage system, the energy state consistency control factor is calculated from the perspective of battery energy state.

[0068] Preferably, the available energy includes rechargeable energy, wherein the energy state consistency control factor is determined as follows: if the charge / discharge state is the charging state, then based on the state of charge, state of health, and rated energy, the rechargeable energy SOEch corresponding to a single cell and the maximum rechargeable energy corresponding to all single cells are determined respectively; the relative difference of rechargeable energy between the rechargeable energy corresponding to a single cell and the maximum rechargeable energy SOEch_max is calculated; and the square of the relative difference of rechargeable energy is determined as the energy state consistency control factor.

[0069] Specifically, the energy state consistency control factor kbe is calculated using the following formula:

[0070] kbe=[(SOEch-SOEch_max) / SOEch_max] 2

[0071] In a preferred embodiment, the available energy includes releasable energy, wherein the energy state consistency control factor is determined as follows: if the charge / discharge state corresponding to the energy storage system is the discharge state, then based on the state of charge, state of health, and rated energy, the releasable energy SOEdis corresponding to a single cell and the maximum releasable energy SOEdis_max corresponding to all single cells are determined respectively. The relative difference of releasable energy between the releasable energy corresponding to a single cell and the maximum releasable energy is calculated, and the square of the relative difference of releasable energy is determined as the energy state consistency control factor.

[0072] If the energy storage system is in a discharge state, the energy state consistency control factor kbe is calculated using the following formula:

[0073] kbe=[(SOEdis-SOEdis_max) / SOEdis_max] 2

[0074] In one specific embodiment, the on / off control method of a single battery is considered from the perspective of battery energy state dimension. The principle followed is: during charging, single batteries with larger rechargeable energy are given priority; during discharging, single batteries with larger rechargeable energy are given priority; and during discharging, single batteries with larger dischargeable energy are given priority. Therefore, when calculating the energy state consistency control factor corresponding to a single battery, it is necessary to first determine the charge / discharge state corresponding to the energy storage system. Then, based on the state of charge (SOC), state of health (SOH), and rated energy (E0) corresponding to the single battery, the rechargeable energy (SOEch) and dischargeable energy (SOEdis) corresponding to the single battery are calculated. Wherein, rechargeable energy (SOEch) = (1-SOC) × SOH × E0, and dischargeable energy (SOEdis) = SOC × SOH × E0. Furthermore, from the rechargeable energy and dischargeable energy corresponding to multiple single batteries, the maximum rechargeable energy (SOEch_max) and the maximum dischargeable energy (SOEdis_max) are determined.

[0075] In one example, the energy state consistency control factor can also be determined using the following formula:

[0076] kbe=FS×[(SOEch-SOEch_max) / SOEch_max] 2 +(1-FS)

[0077] ×[(SOEdis-SOEdis_max) / SOEdis_max] 2

[0078] In this formula, kbe represents the energy state consistency control factor, FS represents the charge / discharge state of the energy storage system, FS=1 indicates that the energy storage system is in a charging state, and FS=0 indicates that the energy storage system is in a discharging state.

[0079] Specifically, the smaller the energy state consistency control factor kbe, the higher the call priority of the corresponding battery cell.

[0080] In a preferred embodiment, in step S2001, the power state consistency control factor is determined in the following manner:

[0081] Determine the maximum power state value for all individual cells, calculate the relative power state difference between the power state value for each individual cell and the maximum power state value, and determine the power state consistency control factor by squared the relative power state difference.

[0082] Specifically, considering the priority of individual battery usage from the perspective of battery power state dimension, the principle followed is: prioritize the use of individual batteries with higher power state of operation (SOP). Therefore, first determine the maximum power state of operation (SOPmax) corresponding to all individual batteries. Then, calculate the relative power state difference between the power state of operation (SOP) of the individual battery and the maximum power state of operation (SOPmax). The relative power state difference is determined as the power state consistency factor (kbp) of the individual battery. The smaller the power state consistency factor (kbp), the higher the usage priority of the individual battery.

[0083] In one specific embodiment, the power state consistency factor (kbp) corresponding to a single cell is determined by the following formula:

[0084] kbp = [(SOP - SOPmax) / SOPmax] 2

[0085] In step S2001, the temperature consistency control factor corresponding to a single cell is calculated in the following way: the temperature control factor corresponding to a single cell is determined based on the battery temperature and the relationship function between the battery temperature and the temperature control factor.

[0086] The determination of the temperature control factor kbtem starts from the battery temperature dimension. First, a relationship function between the battery temperature and the temperature control factor is established. Preferably, the relationship function is determined in the following way:

[0087] A relationship function is constructed using linear interpolation based on the minimum operating temperature, maximum operating temperature, and temperature control factor corresponding to the optimal operating temperature of the battery.

[0088] For details, please refer to Figure 5 , Figure 5This diagram illustrates a relationship function between battery temperature and temperature control factor according to an embodiment of this application. Figure 5 As shown, when the battery temperature is greater than the given upper limit of battery temperature, or when the battery temperature is less than the given lower limit of battery temperature, the temperature control factor kbtem = 1. The given upper limit of battery temperature is the maximum battery application temperature TMAX, and the given lower limit of battery temperature is the minimum battery application temperature TMIN. The optimal battery application temperature is between the maximum and minimum battery application temperatures. When the battery temperature of a single cell is at the optimal battery application temperature T0, the temperature control factor is 0. The optimal battery application temperature is between the maximum and minimum battery application temperatures. Figure 5 In addition to the optimal battery application temperature, maximum battery application temperature, and minimum battery application temperature, other temperatures within the range of maximum and minimum battery application temperatures are obtained by linear interpolation to obtain the corresponding temperature control factor. In this application, the smaller the temperature control factor kbtem, the higher the priority of the single cell.

[0089] In step S2001, the temperature uniformity control factor corresponding to a single cell is calculated using the following formula:

[0090] Calculate the average temperature of all individual cells, calculate the relative temperature difference between the battery temperature and the average temperature of all individual cells, and determine the square of the relative temperature difference as the temperature consistency control factor for the individual cells.

[0091] Because the self-discharge and degradation coefficients of individual batteries differ at different temperatures, in order to ensure the consistency of all batteries, the priority of individual battery usage is considered from the perspective of average temperature. The principle followed is to operate all individual batteries at the same temperature as much as possible. Therefore, the average temperature T_ave corresponding to all individual batteries is first calculated. Then, the third difference between the battery temperature T of the individual battery and the average temperature T_ave is calculated. The third difference is determined as the temperature consistency control factor kbtem_ave corresponding to the individual battery. The smaller the temperature consistency control factor kbtem_ave, the higher the usage priority of the individual battery.

[0092] Preferably, the temperature uniformity control factor for a single cell is calculated using the following formula:

[0093] kbtem_ave = [(T-T_ave) / T_ave] 2

[0094] return Figure 2In steps S100 to S500, considering the potential redundancy design of energy storage units in the energy storage system, the method further includes:

[0095] To determine whether there is redundant design in the individual cells of the energy storage system, if there is redundant design, all individual cells in the energy storage system are identified as candidate individual cells. If there is no redundant design, the difference between the multidimensional control factor corresponding to each individual cell and the minimum multidimensional control factor corresponding to each individual cell is calculated. For each individual cell, the difference value corresponding to the individual cell is compared with the preset control factor limit. If the difference value corresponding to the individual cell is greater than the preset control factor limit, the individual cell is identified as an unusable cell and bypassed. If the difference value corresponding to the individual cell is less than or equal to the preset control factor limit, the individual cell is identified as a candidate individual cell.

[0096] Within a preset calculation cycle, based on the sorting results, the output required voltage, and the maximum supply voltage of each candidate cell in the next AC cycle, the nearest level approximation method is applied to control the operation mode of each candidate cell in the next AC cycle.

[0097] In one specific embodiment, when there is a redundant design of individual batteries in the energy storage system, it means that only some energy storage units in the energy storage system need to be connected to the charging and discharging circuit of the energy storage system at the same time to meet the peak reference voltage of the energy storage system. At this time, all individual batteries in the energy storage system are determined as candidate individual batteries, and steps S200 to S500 are executed once every preset calculation cycle.

[0098] In another specific embodiment, when there is no redundancy design in the individual batteries of the energy storage system, it means that all energy storage units in the energy storage system need to be connected to the charging and discharging circuit of the energy storage system at the same time in order to meet the peak reference voltage of the energy storage system. At this time, when some energy storage units fail or there are energy storage units with large differences, it is necessary to bypass the abnormal energy storage units, that is, the use of individual batteries with failure or large differences is not considered.

[0099] Therefore, in this application, every preset calculation cycle, it is necessary to screen the individual cells in the energy storage system and bypass the individual cells that have faults or large differences in multidimensional control factors so that they do not participate in the charging and discharging of the energy storage system in the next AC cycle.

[0100] Specifically, the difference value K_var between the multidimensional control factor corresponding to a single cell and the minimum multidimensional control factor corresponding to all single cells is calculated. For each single cell, the larger the difference value K_var, the greater the difference between the single cell and other single cells. When the K_var of the single cell is greater than the preset control factor limit Kvar_limit, it indicates that the single cell is an unusable cell, that is, the single cell is not suitable for participating in the charging and discharging of the next AC cycle. In this case, the single cell is bypassed directly, and only single cells with a difference value less than or equal to the preset control factor limit are identified as candidate single cells. Steps S200 to S500 are executed once every preset calculation cycle.

[0101] In a preferred embodiment, the operating mode of each individual cell during the output voltage rise phase of the next AC cycle is determined by the following method:

[0102] A sequence of individual cells is determined, which includes multiple individual cells arranged according to the sorting result. For each moment during the output voltage rise phase: the connected voltage corresponding to that moment is determined, which is the sum of the maximum supply voltages corresponding to the connected individual cells. The output demand voltage is compared with the connected voltage corresponding to that moment, and the comparison result is determined. Based on the comparison result, the individual cell sequence, and the maximum supply voltage corresponding to each individual cell, the individual cell that performs the target conduction action at that moment is selected from the individual cell sequence.

[0103] For preferred options, please refer to [link / reference]. Figure 6 , Figure 6 A schematic diagram illustrating the output voltage requirement of an energy storage system according to an embodiment of this application is shown. Figure 6 As shown, the output demand voltage of the energy storage system is a sinusoidal voltage. The output voltage rise phase includes a forward rise phase (Part I) and a reverse rise phase (Part III). The conduction action includes a forward conduction action corresponding to the forward rise phase and a reverse conduction action corresponding to the reverse rise phase. The method further includes:

[0104] During the positive rising phase of the output voltage, the target conduction action is a forward conduction action; during the reverse rising phase of the output voltage, the target conduction action is a reverse conduction action.

[0105] In a preferred embodiment, the individual cell that performs the target turn-on action at each moment during the output voltage rise phase is determined by the following method:

[0106] If the output demand voltage is greater than or equal to the total voltage already connected at that moment, then a single cell is selected from the unconnected single cells in the single cell sequence. The selected single cell is the single cell with the smallest multidimensional control factor among the unconnected single cells. The selected single cell is determined as the connected battery to perform the target conduction action at that moment, and the connection status of the selected single cell is updated to connected. If the output demand voltage is less than the total voltage already connected, then it is determined that no battery connection will be performed at that moment.

[0107] In one specific embodiment, the single-cell sequence includes multiple single-cells arranged in ascending order. Taking Part I, the stage where the output voltage is rising, as an example, the target conduction action is a forward conduction action. For each time t corresponding to Part I, the required output voltage V at that time is determined. t and connected to the total voltage V P Assume V at this time P =0, then V t >V P Then, the first cell in the cell sequence, Bat1, is selected as the access cell to perform forward conduction at time t, and the access voltage V is updated. P =V pre1 V pre1 This indicates the maximum supply voltage corresponding to the single cell Bat1. Then, comparisons and judgments are continued, and V is... t With V P =V pre1 Compare, if V t >V P =V pre1 Next, select the next single cell, Bat2, as the connected cell to perform the forward conduction operation. Similarly, update the total voltage V. P =V pre1 +V pre2 V pre2 This indicates the maximum supply voltage corresponding to a single battery cell, Bat2, and so on.

[0108] If there exists a V corresponding to time t t <V P If the output voltage requirement of the energy storage system is met, then it is determined that the battery will not be connected at this moment, and the next step V is executed. t+1 The corresponding connected battery is determined and processed.

[0109] Using the above method, the number of connected batteries k corresponding to Part I, the positive rise stage of the output demand voltage in the next AC cycle, can be determined. Among the multiple individual batteries, the individual batteries other than the k connected batteries are determined as bypass batteries, and their corresponding number is Nk, where N is the total number of individual batteries in the single-phase bridge arm of the energy storage system.

[0110] Furthermore, the k access batteries corresponding to the positive rising part Part I can be sorted according to the multidimensional control factor from smallest to largest and the access time corresponding to each access battery, to determine the first access order of the k access batteries in the positive rising part Part I of the next AC cycle. Assuming that at time t1 of the positive rising part Part I of the next AC cycle, the corresponding access batteries include Bat1 and Bat2, and at time t2 of the positive rising part Part I of the next AC cycle, the corresponding access batteries include Bat3, then the access batteries corresponding to time t1 and time t2 are sorted according to the multidimensional control factor from smallest to largest, and the result is (Bat1, Bat2, Bat3). Then, combined with the access time corresponding to each battery, the first access order is determined to be (Bat1, Bat2, Bat3).

[0111] During the output voltage rise phase of the next AC cycle, multiple connected batteries can be controlled to sequentially perform the corresponding target conduction actions according to the first connection sequence (Bat1, Bat2, Bat3) and the connection time corresponding to each connected battery.

[0112] In another specific embodiment, for the output voltage reverse rising phase corresponding to the next AC cycle, the method for determining the corresponding connected battery and its connection time is similar to that for the output voltage forward rising phase. The difference is that, based on the determined first connection sequence and the connection time corresponding to each connected battery, the target conduction action performed on each connected battery in the reverse rising phase of the next AC cycle is changed to a reverse conduction action.

[0113] In a preferred embodiment, the AC cycle further includes an output voltage drop phase, wherein the operation mode of each individual cell in the output voltage drop phase of the next AC cycle is determined by the following method:

[0114] A battery access sequence is determined, which includes multiple access batteries sorted from smallest to largest according to multidimensional control factors. For each moment in the output voltage drop phase, a battery cut-off determination process is performed on the battery access sequence. Based on the battery cut-off process result at each moment, the action mode corresponding to the multiple access batteries is determined.

[0115] Preferably, the battery cut-off determination process includes: summing the maximum supply voltages of the remaining connected batteries in the battery access sequence (excluding the battery to be operated), determining the summation result, where the battery to be operated is the connected battery located at the end of the battery access sequence; comparing the summation result with the output demand voltage corresponding to that moment; if the summation result is less than or equal to the output demand voltage corresponding to that moment, determining that the battery to be operated should be subjected to a target bypass action at that moment; removing the battery to be operated from the battery access sequence; if the summation result is greater than the output demand voltage corresponding to that moment, returning to execute the battery cut-off determination process for the next moment.

[0116] Preferably, the output demand voltage decrease phase includes a forward output demand voltage decrease phase Part II and a reverse output demand voltage decrease phase Part IV. The bypass action includes a forward bypass action corresponding to the forward output voltage decrease phase and a reverse bypass action corresponding to the reverse output voltage decrease phase. The method further includes: for the forward output voltage decrease phase, the target bypass action is a forward bypass action; for the reverse output voltage decrease phase, the target bypass action is a reverse bypass action.

[0117] In one specific embodiment, taking Part II, the positive decreasing portion of the output voltage corresponding to the next AC cycle, as an example, for each time t corresponding to Part II, a battery disconnection determination process is performed: for the battery access sequence, the disconnection order and disconnection time of the accessed batteries are determined, and the specific execution method is as follows:

[0118] The maximum supply voltages of the first k-1 individual cells in the battery access sequence are summed to obtain... V_pre(i) represents the maximum supply voltage corresponding to the i-th single cell in the battery access sequence, and the output demand voltage V of the energy storage system at time t. t and If a comparison is made, The k-th individual cell is then identified as the cut-off battery, and time t is defined as the cut-off time of the cut-off battery in the positive downward part II. The k-th individual cell is then removed from the battery access sequence. The next cut-off battery corresponding to time t is then determined. Specifically, for determining the next cut-off battery, the maximum supply voltages corresponding to k-2 individual cells are summed to obtain... like Then the (k-2)th single cell is identified as the cut-off cell, and so on.

[0119] If there exists a time t corresponding to At this point, the battery to be operated on is abandoned as the battery to be cut off, and the battery cut-off determination process corresponding to this moment is stopped. The next moment V is then executed. t+1 The corresponding battery disconnection procedure is determined.

[0120] Using the above method, the battery to be cut off during Part II of the positive voltage drop phase can be determined, as well as the cut-off time for each battery.

[0121] Furthermore, according to the multidimensional control factors from smallest to largest and the cut-off time corresponding to each cut-off battery, the cut-off batteries corresponding to Part II of the positive voltage drop phase are sorted to determine the second access order of the cut-off batteries in Part II of the positive voltage drop phase.

[0122] According to the second access sequence and the corresponding cut-off time for each cut-off battery, a forward bypass operation is performed on each cut-off battery.

[0123] In another specific embodiment, for the output voltage reverse drop phase corresponding to the next AC cycle, the method for determining the corresponding disconnected battery and its disconnection time and disconnection sequence is similar to that for the output voltage forward drop phase. The difference is that, according to the determined second access sequence and the disconnection time corresponding to each disconnected battery, a reverse bypass action needs to be performed on each disconnected battery during the output voltage reverse drop phase.

[0124] Compared with existing technologies, the beneficial effects of this technical solution are as follows:

[0125] 1. Improve battery energy utilization: This invention sorts and controls the access status of energy storage units through multi-dimensional control factors, which can more accurately match the needs of the energy storage system, thereby improving the utilization rate of battery energy.

[0126] 2. Enhanced battery consistency management: By considering multiple dimensions such as battery state of charge, state of health, state of energy, and temperature, this invention can better manage the consistency issues of batteries of different types, capacities, manufacturers, and batches.

[0127] 3. Extend battery life: By optimizing the connection status and time of each individual battery cell, this invention can reduce overcharging and over-discharging of the battery, thereby extending the battery life.

[0128] 4. Improved system stability and reliability: The control method of the present invention can dynamically adjust the battery connection according to the real-time status of the energy storage system, thereby improving the stability and reliability of the energy storage system.

[0129] 5. Strong adaptability: The method of the present invention is not only applicable to a single type of battery energy storage system, but also adaptable to energy storage systems with multiple battery combinations, and has strong adaptability and flexibility.

[0130] Based on the same application concept, this application also provides a control device for an energy storage system corresponding to the energy storage system control method provided in the above embodiments. Since the principle of the device in this application is similar to the energy storage system control method in the above embodiments of this application, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be described again.

[0131] Please see Figure 7 , Figure 7 This diagram illustrates the functional block diagram of a control device for an energy storage system according to an embodiment of this application. Figure 7 As shown, the energy storage system includes multiple energy storage units and an energy storage controller. Each energy storage unit includes a single battery cell. The method is applied to the energy storage controller, and the device includes:

[0132] The first determining module 600 is used to determine the state parameters corresponding to each individual battery cell;

[0133] The second determining module 610 is used to determine the multi-dimensional control factor corresponding to each individual cell at every preset calculation cycle, based on the different state dimensions indicated by the state parameters corresponding to the individual cell.

[0134] The sorting module 620 is used to sort multiple individual cells according to the charge and discharge state of the energy storage system and multi-dimensional control factors.

[0135] The third determining module 630 is used to determine the output demand voltage of the energy storage system based on the peak reference voltage and AC frequency of the energy storage system.

[0136] The control module 640 is used to control the connection status of each individual cell in the next AC cycle based on the sorting results, the output demand voltage, and the maximum supply voltage of each individual cell in the next AC cycle, by applying the nearest level approximation method.

[0137] Based on the same application concept, please refer to Figure 8 , Figure 8 This diagram illustrates the structure of an electronic device according to an embodiment of this application. The electronic device 700 includes a processor 710, a memory 720, and a bus 730. The memory 720 stores machine-readable instructions executable by the processor 710. When the electronic device 700 is running, the processor 710 and the memory 720 communicate via the bus 730. The machine-readable instructions are executed by the processor 710 to perform the steps of any of the energy storage system control methods provided in the above embodiments.

[0138] Based on the same concept, this application also provides a computer-readable storage medium storing a computer program, which, when run by a processor, executes the steps of the energy storage system control method provided in the above embodiments.

[0139] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems and devices described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division; in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the displayed or discussed mutual coupling or direct coupling or communication connection may be through some communication interfaces; the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms.

[0140] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0141] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0142] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0143] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A control method for an energy storage system, characterized in that, The energy storage system includes multiple energy storage units and an energy storage controller. Each energy storage unit includes a single battery cell, and the method is applied to the energy storage controller. The method includes: Determine the state parameters corresponding to each individual cell; Every preset calculation cycle, for each individual cell, the multidimensional control factor corresponding to that individual cell is determined based on the different state dimensions indicated by the state parameters corresponding to that individual cell. Multiple individual cells are sorted according to the charge / discharge state of the energy storage system and multi-dimensional control factors; The output required voltage of the energy storage system is determined based on the peak reference voltage and AC frequency corresponding to the energy storage system. Based on the sorting results, the output required voltage, and the maximum supply voltage of each individual cell in the next AC cycle, the nearest level approximation method is applied to control the connection status of each individual cell in the next AC cycle.

2. The method according to claim 1, characterized in that, The state parameters include state of charge, state of health, state of energy, state of power, and battery temperature. The multidimensional control factor is determined in the following manner: Based on the state parameters corresponding to each individual cell, determine the health state consistency control factor, energy state consistency control factor, power state consistency control factor, temperature control factor, and temperature consistency control factor corresponding to each individual cell. The health status consistency control factor, energy status consistency control factor, power status consistency control factor, temperature control factor, and temperature consistency control factor are weighted and calculated to determine the multidimensional control factor for each individual cell.

3. The method according to claim 2, characterized in that, The health status consistency control factor is determined in the following ways: Determine the maximum health status value for all individual cells in the energy storage system; Calculate the relative difference in health status between the health status of a single cell and the maximum health status value; The square of the relative difference in health status is determined as the health status consistency control factor.

4. The method according to claim 2, characterized in that, The energy state consistency control factor is determined in the following manner: The available energy of a single cell is determined by using the state of charge, the state of health, and the rated energy of the single cell. Based on the available energy of a single battery cell and the charge / discharge state of the energy storage system, an energy state consistency control factor is calculated from the perspective of battery energy state.

5. The method according to claim 4, characterized in that, The available energy includes rechargeable energy. The energy state consistency control factor is determined in the following manner: If the charging / discharging state is the charging state, then based on the state of charge, the health state, and the rated energy, the rechargeable energy corresponding to a single cell and the maximum rechargeable energy corresponding to all single cells are determined respectively. Calculate the relative difference in rechargeable energy between the rechargeable energy of a single battery cell and its maximum rechargeable energy value; The square of the relative difference in rechargeable energy is determined as the energy state consistency control factor.

6. The method according to claim 4, characterized in that, The available energy includes releaseable energy. The energy state consistency control factor is determined in the following manner: If the energy storage system is in a discharge state, then the energy that can be discharged for a single cell and the maximum energy that can be discharged for all single cells are determined according to the state of charge, the health state and the rated energy. Calculate the relative difference in energy release between the energy release capacity of a single cell and the maximum energy release capacity; The square of the relative difference in the releaseable energy is determined as the energy state consistency control factor.

7. The method according to claim 2, characterized in that, The power state consistency control factor is determined in the following manner: Determine the maximum power state value for all individual cells; Calculate the relative power state difference between the power state corresponding to each individual cell and the maximum power state value; The power state consistency control factor is determined by the square of the relative difference in power state.

8. The method according to claim 2, characterized in that, The temperature uniformity control factor for a single cell is calculated using the following method: Based on the battery temperature and the relationship function between battery temperature and temperature control factor, the temperature control factor corresponding to a single cell is determined.

9. The method according to claim 8, characterized in that, When the temperature of a single battery cell is greater than or equal to the maximum operating temperature or less than or equal to the minimum operating temperature, the temperature control factor is 1. When the temperature of a single battery cell is at its optimal operating temperature, the temperature control factor is 0. The relational function is determined in the following manner: The relationship function is constructed by linear interpolation based on the minimum battery application temperature, the maximum battery application temperature, and the temperature control factor corresponding to the optimal battery temperature.

10. The method according to claim 2, characterized in that, The temperature uniformity control factor for a single cell is calculated using the following formula: Calculate the average temperature corresponding to all individual cells; Calculate the relative temperature difference between the battery temperature and the average temperature of all individual cells; The square of the relative temperature difference is determined as the temperature consistency control factor for the individual cell.

11. The method according to claim 2, characterized in that, The multidimensional control factor is determined using the following formula: K=k1×kbh+k2×kbe+k3×kbp+k4×kbtem+k5×kbtem_ave In this formula, k1 represents the first given weight corresponding to the health state consistency control factor kbh, k2 represents the second given weight corresponding to the energy state consistency control factor kbe, k3 represents the third given weight corresponding to the power state consistency control factor kbp, k4 represents the fourth given weight corresponding to the temperature control factor kbtem, and k5 represents the fifth given weight corresponding to the temperature consistency control factor kbtem_ave. k1+k2+k3+k4+k5=1.

12. The method according to claim 1, characterized in that, The method further includes: Determine whether there is redundancy in the individual battery cells of the energy storage system; If there is a redundant design in the energy storage system, then all individual cells in the energy storage system will be identified as candidate individual cells. If there is no redundant design in the energy storage system, the difference between the multidimensional control factor corresponding to each individual cell and the minimum multidimensional control factor corresponding to each individual cell is calculated. For each individual battery cell, the difference value corresponding to that individual battery cell is compared with a preset control factor limit. If the difference value corresponding to that individual battery cell is greater than the preset control factor limit, then that individual battery cell is determined to be an unusable battery and is bypassed. If the difference value corresponding to the single cell is less than or equal to the preset control factor limit, then the single cell is determined as a candidate single cell. Within a preset calculation cycle, based on the sorting results, the output required voltage, and the maximum supply voltage of each candidate cell in the next AC cycle, the nearest level approximation method is applied to determine the operation mode of each candidate cell in the next AC cycle.

13. The method according to claim 1, characterized in that, The AC cycle includes the output voltage rise phase. The operation mode of each individual battery cell during the output voltage rise phase is determined in the following way: For each moment of the output voltage rise phase: Determine the sequence of individual cells and the corresponding connected voltage at that moment. The sequence of individual cells includes multiple individual cells arranged according to the sorting result. The connected voltage is the sum of the maximum supply voltages corresponding to the connected individual cells. The required output voltage is compared with the current connected voltage at that moment, and the comparison result is determined. Based on the comparison results, the individual cell sequence, and the maximum supply voltage corresponding to each individual cell, the individual cell that performs the target conduction action at that moment is selected from the individual cell sequence.

14. The method according to claim 13, characterized in that, The output voltage rise phase includes a forward output voltage rise phase and a reverse output voltage rise phase. The conduction action includes a forward conduction action corresponding to the forward output voltage rise phase and a reverse conduction action corresponding to the reverse output voltage rise phase. The method further includes: During the positive rising phase of the output voltage, the target conduction action is a positive conduction action; During the reverse rising phase of the output voltage, the target conduction action is a reverse conduction action.

15. The method according to claim 13, characterized in that, The individual cell that performs the target conduction action at each moment during the output voltage rise phase is determined in the following way: If the required output voltage is greater than or equal to the total voltage already connected at that moment, then a single cell is selected from the unconnected single cells in the single cell sequence in sequence. The selected single cell is the single cell with the smallest multidimensional control factor among the unconnected single cells. The selected individual battery is identified as the access battery that performs the target conduction action at this moment, and the access status of the selected individual battery is updated to "accessed". If the required output voltage is less than the total voltage already connected, then it is determined that the battery will not be connected at that moment.

16. The method according to claim 13, characterized in that, The AC cycle also includes an output voltage drop phase. The operating mode of each individual cell during the output voltage drop phase of the next AC cycle is determined in the following way: Determine the battery access sequence, which includes multiple access batteries sorted in ascending order according to a multidimensional control factor; For each moment of the output voltage drop phase, a battery cut-off determination process is performed on the battery access sequence; The action mode corresponding to the multiple connected batteries is determined by the battery disconnection processing result at each time moment.

17. The method according to claim 16, characterized in that, The battery disconnection process includes: The maximum supply voltages of the remaining connected batteries in the battery access sequence, excluding the battery to be activated, are summed to determine the summation result. The battery to be activated is the connected battery located at the end of the battery access sequence. Compare the summation result with the output demand voltage corresponding to that moment; If the summation result is less than or equal to the output demand voltage at that moment, then it is determined that a target bypass action will be performed on the battery to be operated at that moment. Remove the battery to be operated from the battery access sequence; If the summation result is greater than the output demand voltage at that moment, then return to execute the battery cut-off determination process for the next moment.

18. The method according to claim 17, characterized in that, The output voltage drop phase includes a forward output voltage drop phase and a reverse output voltage drop phase. The bypass operation includes a forward bypass operation corresponding to the forward output voltage drop phase and a reverse bypass operation corresponding to the reverse output voltage drop phase. The method further includes: During the positive decreasing phase of the output voltage, the target bypass action is a positive bypass action; During the reverse voltage drop phase, the target bypass action is a reverse bypass action.

Images