Charging control method, energy storage system and medium

Abstract

The invention relates to the technical field of energy storage, and discloses a charging control method, an energy storage system and a medium. The method is applied to a master station, and comprises the following steps: determining a target voltage range according to the current voltage of each slave station; obtaining a target charging request voltage according to the target voltage range and the current charging request voltage; the target charging request voltage is sent to an inverter, so that the target charging voltage is output to each slave station through the inverter according to the target charging request voltage, the charging current of a charging loop between the inverter and a target slave station is suppressed, and the target slave station is the slave station of which the current voltage is greater than the target charging voltage in each slave station. Thus, the charging current of the charging loop between the inverter and the slave station can be suppressed by dynamically adjusting the charging request voltage, and the small-current charging phenomenon of the charging loop between the inverter and the slave station is avoided, so that overvoltage of the slave station is avoided, the service life of the slave station is prolonged, and the performance of the slave station is improved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a charging control method, an energy storage system and a medium. Background Art

[0002] At present, in the energy storage system, the grid is connected to the battery through the inverter, and the inverter transmits the power of the grid to the battery. In the prior art, the following method is used to avoid battery overcharging: adjust the output current of the inverter to control the charging state of the battery, thereby avoiding battery overcharging. Due to the working characteristics of the inverter, the inverter will output a small current to continuously charge the battery, causing battery overvoltage, which in turn affects the battery life and performance. Summary of the invention

[0003] In view of this, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a charging control method, an energy storage system and a medium. The present invention provides the following technical solutions:

[0004] In a first aspect, the present invention provides a charging control method, which is applied to a master station, wherein the master station is electrically connected to an inverter and at least one slave station, respectively, and the inverter is also electrically connected to each of the slave stations, respectively, and the method comprises: determining a target voltage range according to a current voltage of each of the slave stations; obtaining a target charging request voltage according to the target voltage range and a current charging request voltage; sending the target charging request voltage to the inverter, so as to output the target charging voltage to each of the slave stations through the inverter according to the target charging request voltage, thereby suppressing the charging current of the charging circuit between the inverter and the target slave station, the target slave station being a slave station among the slave stations whose current voltage is greater than the target charging voltage.

[0005] In one embodiment, the method also includes: obtaining a charging request voltage range of the inverter according to the number and model of each of the slave stations, and determining a charging request minimum voltage threshold according to the charging request voltage range; obtaining a target charging request voltage according to the target voltage range and the current charging request voltage includes: determining a target voltage value according to the target voltage range; if the target voltage value is less than or equal to the charging request minimum voltage threshold, determining the target charging request voltage according to the target voltage value and the charging request minimum voltage threshold; if the target voltage value is greater than the charging request minimum voltage threshold, determining the charging request voltage according to the target voltage value, the current charging request voltage and the charging request minimum voltage threshold.

[0006] In one embodiment, determining the target charging request voltage according to the target voltage value and the charging request minimum voltage threshold includes: determining the charging request minimum voltage threshold as the target charging request voltage.

[0007] In one embodiment, the charging request voltage is determined based on the target voltage value, the current charging request voltage and the charging request minimum voltage threshold, including: if the charging request minimum voltage threshold < the target voltage value < the current charging request voltage, the target voltage value is determined as the target charging request voltage; if the charging request minimum voltage threshold < the current charging request voltage < the target voltage value, the current charging request voltage is determined as the target charging request voltage; if the current charging request voltage < the charging request minimum voltage threshold < the target voltage value, the charging request minimum voltage threshold is determined as the target charging request voltage.

[0008] In one embodiment, the target voltage range includes the current voltage of some or all of the slave stations, and determining the target voltage value based on the target voltage range includes: determining an initial voltage value based on the sorting results of the current voltages of some or all of the slave stations; and determining the target voltage value based on the initial voltage value and a preset voltage offset range of the slave station.

[0009] In one embodiment, determining the target voltage value based on the initial voltage value and the preset voltage offset range of the slave station includes: determining the target offset voltage value based on the preset voltage offset range; subtracting the target offset voltage value from the initial voltage value to obtain the target voltage value.

[0010] In one embodiment, the slave station includes a battery pack, and the battery pack includes battery cells. The charging request voltage range of the inverter is obtained according to the number and model of each of the slave stations, including: determining the operating voltage and redundant voltage range of each of the battery cells according to the model of the battery cells; determining the charging request voltage range according to the operating voltage, the redundant voltage range and the number of each of the battery cells.

[0011] In one embodiment, the method further includes: obtaining a charging request current, and if the charging request current is within a preset charging current range of the slave station, executing the step of determining the target voltage range according to the current voltage of each of the slave stations.

[0012] In a second aspect, the present invention provides a charging and storage energy system, the system comprising: a master station, an inverter and at least one slave station; the master station is electrically connected to the inverter and each of the slave stations respectively; the inverter is also electrically connected to each of the slave stations respectively; the master station is used to determine a target voltage range according to the current voltage of each of the slave stations; obtain a target charging request voltage according to the target voltage range and the current charging request voltage; send a target charging request voltage to the inverter, so as to output the target charging voltage to each of the slave stations through the inverter according to the target charging request voltage, thereby suppressing the charging current of the charging circuit between the inverter and the target slave station, the target slave station being a slave station among the slave stations whose current voltage is greater than the target charging voltage.

[0013] In a third aspect, the present invention provides a computer storage medium storing a computer program, wherein when the computer program is executed on a processor, the charging control method described in the first aspect is implemented.

[0014] The charging control method, energy storage system and medium provided by the present invention determine the target voltage range according to the current voltage of each slave station; obtain the target charging request voltage according to the target voltage range and the current charging request voltage; send the target charging request voltage to the inverter, so that the inverter outputs the target charging voltage to each slave station according to the target charging request voltage, and suppresses the charging current of the charging circuit between the inverter and the target slave station, and the target slave station is a slave station among the slave stations whose current voltage is greater than the target charging voltage. In this way, the charging current of the charging circuit between the inverter and the slave station can be suppressed by dynamically adjusting the charging request voltage, thereby avoiding the small current charging phenomenon of the charging circuit between the inverter and the slave station, thereby avoiding overvoltage of the slave station and improving the life and performance of the slave station. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be regarded as limiting the scope of protection of the present application. For ordinary technicians in this field, other related drawings can also be obtained based on these drawings without creative work.

[0016] Figure 1 A schematic diagram of the structure of an energy storage system provided by an embodiment of the present invention is shown;

[0017] Figure 2 A schematic diagram of a flow chart of a charging control method provided by an embodiment of the present invention is shown;

[0018] Figure 3 A schematic diagram of a flow chart of step S200 of the charging control method provided by an embodiment of the present invention is shown;

[0019] Figure 4 A schematic diagram of a flow chart of step S201 of the charging control method provided by an embodiment of the present invention is shown;

[0020] Figure 5 A flow chart of step S2012 of the charging control method provided in an embodiment of the present invention is shown.

[0021] Description of main components symbols:

[0022] 100-master station; 200-inverter; 300-slave station; 301-target slave station. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0024] The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0025] Hereinafter, the terms "including", "having" and their cognates, which may be used in various embodiments of the present application, are intended only to indicate specific features, numbers, steps, operations, elements, components, or combinations of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing items or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations of the foregoing items.

[0026] Furthermore, the terms “first”, “second”, “third”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0027] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as those generally understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meanings as the contextual meanings in the relevant technical field and will not be interpreted as having idealized meanings or overly formal meanings unless clearly defined in the various embodiments of the present application.

[0028] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0029] The charging control method provided in this application is applicable to any energy storage charging scenario using an inverter, for example, it can be applied to an energy storage system including an inverter. The energy storage system includes a master station, an inverter, and at least one slave station, wherein the master station can be a Battery Management System (BMS), and the slave station can be a battery pack. By adopting the charging control method provided in this implementation, overvoltage can be avoided when the inverter charges the slave station, thereby improving the life and performance of the slave station.

[0030] Generally speaking, an inverter is an AC / DC power conversion device. In an energy storage system, the inverter is connected between the power grid and the battery pack. The inverter is used to realize the bidirectional flow of electric energy between the power grid and the battery pack. The power grid charges the battery pack through the inverter. When the battery pack is fully charged, the battery management system determines that the charging request current is 0 based on the current charging status of the battery. At this time, the charging request current sent by the battery management system to the inverter is 0. In actual applications, due to the working characteristics of the inverter and other reasons, the inverter cannot accurately adjust the output current to 0, and there is always a small current output to the battery, resulting in continuous charging of the battery pack. If this situation lasts too long, it will cause the battery pack to be over-voltage, thereby affecting the life and performance of the battery pack, and even causing the charge and discharge circuit controlled by the contactor to be disconnected, resulting in system downtime and serious safety accidents. The following is combined with Figure 1-Figure 5 , the charging control method provided in this application is illustrated by way of example.

[0031] See also Figure 1 , Figure 1 : is a structural diagram of the energy storage system provided in this embodiment, and the energy storage system includes a master station 100, an inverter 200 and at least one slave station 300. Among them, the master station 100 is electrically connected to the inverter 200 and at least one slave station 300 respectively, and the inverter 200 is also electrically connected to each slave station 300 respectively. The master station 100 is a device that performs data aggregation in the energy storage system and can communicate with the inverter 200. For example, the master station 100 can be a BMS. The slave station 300 is a device that stores energy in the energy storage system. For example, the slave station 300 can be a battery pack, and the battery pack has multiple cells, which is not limited here.

[0032] See also Figure 2 , Figure 2 is a flow chart of a charging control method provided in this embodiment, which can be applied to Figure 1 The energy storage system shown in the figure comprises steps S100 to S300. Figure 1-Figure 2Provide explanation.

[0033] Step S100 , determining a target voltage range according to the current voltage of each slave station 300 .

[0034] It is understood that the inverter 200 is also electrically connected to the mains end, and when the inverter 200 is in a charging state, the inverter 200 charges the slave station 300 based on the alternating current provided by the mains end. When the inverter 200 is in a discharging state, the inverter 200 provides electrical energy to the power-consuming device based on the direct current provided by the slave station 300, wherein the power-consuming device can be a household appliance. The master station 100 is provided with a power state (State of Power, SOP) algorithm, and a suitable charging request current is determined according to the state parameters of the slave station 300 by the SOP algorithm, wherein the state parameters of the slave station 300 include the current voltage, temperature and battery capacity, etc. The master station 100 sends a charging request current to the inverter 200, and the inverter 200 outputs the corresponding charging current to the slave station 300 according to the charging request current. It is understood that, ideally, the value of the charging current output by the inverter 200 to the slave station 300 is the same as the value of the charging request current. In actual situations, due to the performance characteristics and regulation accuracy of the inverter, there are some deviations between the value of the charging current output by the inverter 200 to the slave station 300 and the value of the charging request current. For example, ideally, when the charging request current is 0, the output current of the inverter is also 0, and the inverter 200 stops charging each slave station 300. In practice, due to the influence of the electrical characteristics and regulation accuracy of the inverter 200, when the charging request current is 0, the inverter 200 cannot achieve that the output current is also 0. Therefore, relying solely on the charging request current being 0, it is impossible to ensure that the charging current of the charging circuit between the inverter and the slave station is 0. This embodiment proposes to suppress the small current of the charging circuit between the inverter 200 and the slave station 300 from the aspect of adjusting the magnitude relationship between the current voltage of the slave station 300 and the output voltage of the inverter 200.

[0035] In this embodiment, each slave station 300 sends its current voltage to the master station 100, and the master station 100 receives the current voltage sent by each slave station 300, and determines the target voltage range by integrating all the current voltages. The voltage value in the target voltage range is all or part of the current voltage. In addition, the target voltage range can be a voltage range determined according to the key characteristic values ​​in all current voltages, wherein the key characteristic values ​​may include the maximum value, the second largest value, and the minimum value of all current voltages. Exemplarily, when the master station 100 is a BMS and the slave station 300 is a battery pack, the battery pack sends its current voltage to the BMS, and the BMS determines the target voltage range based on all the current voltages received. For example, the BMS can determine all the current voltages as the target voltage range, or determine part of the current voltage as the target voltage range. The BMS can also determine the maximum and minimum values ​​of all current voltages, and determine the target voltage range based on the maximum and minimum values ​​of the current voltages.

[0036] It can be understood that when the inverter 200 charges the slave station 300, the current voltage of the slave station 300 will change accordingly with the change in power. Generally speaking, the higher the power, the greater the voltage of the slave station 300. In this embodiment, the target voltage range is determined by the master station 100 according to the current voltage of each slave station 300, and the charging request voltage for sending to the inverter 200 can be further determined according to the target voltage range, and then the inverter 200 adjusts the charging voltage output to the slave station 300 according to the corresponding charging request voltage.

[0037] Step S200, obtaining a target charging request voltage according to a target voltage range and a current charging request voltage.

[0038] It can be understood that after the current charging request voltage is determined by the SOP algorithm, the master station 100 sends the current charging request voltage to the inverter 200, and the inverter 200 outputs the corresponding charging voltage to the slave station 300 according to the current charging request voltage. It can be understood that, ideally, the value of the charging voltage output by the inverter 200 to the slave station 300 is the same as the value of the current charging request voltage. In actual situations, due to the performance characteristics, adjustment accuracy, etc. of the inverter 200, there are some deviations between the value of the charging voltage output by the inverter 200 to the slave station 300 and the value of the charging request voltage. In order to suppress the small current in the charging circuit between the inverter 200 and the slave station 300, the charging voltage output by the inverter 200 to the slave station 300 needs to be lower than the current voltage of the slave station 300. In order to make the charging voltage output by the inverter 200 to the slave station 300 lower than the current voltage of the slave station 300, it is necessary to dynamically adjust the charging request voltage. That is to say, the master station 100 needs to dynamically adjust the charging request voltage sent to the inverter 200 next time in combination with the target voltage range and the current charging request voltage, and follow the principle of only decreasing and not increasing during the adjustment process.

[0039] Step S300 , sending a target charging request voltage to the inverter 200 , so that the inverter 200 outputs a target charging voltage to each slave station 300 according to the target charging request voltage, thereby suppressing the charging current of the charging circuit between the inverter 200 and the target slave station 301 .

[0040] It can be understood that, for the inverter 200, the charging request voltage sent by the master station 100 to the inverter 200 is the maximum value of the charging voltage provided by the inverter 200 to the slave station 300. At the same time, the inverter 200 will monitor the charging voltage provided to the slave station 300 in real time. When the provided charging voltage is higher than the charging request voltage, the inverter 200 generates a serious overvoltage alarm for the slave station 300, resulting in a serious system failure.

[0041] In this embodiment, the target slave station 301 is a slave station whose current voltage is greater than the target charging voltage among the slave stations. There may be a slave station whose current voltage is greater than or equal to the target charging voltage among the slave stations 300, and there may also be a slave station whose current voltage is less than the target charging voltage among the slave stations 300. It can be understood that due to the existence of the potential difference, for the slave station whose current voltage is greater than or equal to the target charging voltage (i.e., the target slave station 301), the target charging voltage output by the inverter 200 is less than the current voltage of the target slave station 301, thereby suppressing the charging current of the charging circuit between the inverter 200 and the target slave station 301, and the current between the inverter 200 and the target slave station 301 becomes 0, so that the inverter 200 will not charge the target slave station 301, avoid overvoltage of the target slave station 301, and protect the performance of the target slave station 301. Correspondingly, due to the existence of the potential difference, for the slave stations whose current voltage is less than the target charging voltage (i.e., the remaining slave stations except the target slave station 301 among all the slave stations), the target charging voltage output by the inverter 200 is greater than the current voltage of the remaining slave stations, so that there is a charging current in the charging circuit between the inverter 200 and the remaining slave stations, and the charging current is a small current, and the inverter 200 charges the remaining slave stations with a small current. It can be understood that the number of target slave stations 301 can be at least two, which is determined by the number of slave stations whose current voltage is greater than or equal to the target charging voltage. The charging control method can continuously execute steps S100-S300 in a loop, dynamically adjust the charging request voltage, realize the automatic following of the target charging request voltage and the target voltage value, and then perform overvoltage protection on each slave station to avoid the loss of the slave station.

[0042] It is further explained that when the target charging voltage output by the inverter 200 to the slave station is lower than the current voltage of the corresponding slave station, the corresponding slave station (i.e., the target slave station 301) will stop obtaining electrical energy from the inverter 200, thereby enabling the inverter 200 to stop charging the target slave station 301, and suppressing the charging current of the charging circuit between the inverter 200 and the target slave station 301 until the current of the charging circuit between the inverter and the slave station becomes 0.

[0043] It can be understood that when the master station 100 sends a charging request voltage to the inverter 200, in order to prevent the inverter 200 from outputting a target charging voltage that is too low to the slave station 300 according to the charging request voltage, which may cause an overvoltage fault on the energy storage side of the inverter 200, a charging request voltage range for the inverter 200 needs to be set. When the charging request voltage sent by the master station 100 to the inverter 200 is within the charging request voltage range, the target charging voltage output by the inverter 200 to the slave station 300 according to the charging request voltage will not be too low, and the inverter 200 will not have an overvoltage fault on the energy storage side. A voltage value can be selected from the charging request voltage range as the charging request minimum voltage value of the inverter 200, and the minimum output voltage of the inverter 200 is limited by the charging request minimum voltage value. For example, the minimum output voltage of the inverter 200 is greater than or equal to the charging request minimum voltage value.

[0044] Combined with the above analysis, when the charging request current is 0, in order to suppress the charging current between the inverter 200 and each slave station 300, the master station 100 can determine the target charging request voltage according to the charging request voltage range and the target voltage range, and send the target charging request voltage to the inverter 200. The inverter 200 outputs the corresponding target charging voltage to the slave station 300 according to the target charging request voltage, and based on the relationship between the target charging voltage and the current voltage of the slave station 300, the target slave station 301 is determined from each slave station 300 to suppress the charging current of the charging circuit between the inverter 200 and the target slave station 301.

[0045] In this embodiment, the charging control method further includes: acquiring a charging request voltage range of the inverter according to the number and model of each slave station, and determining a charging request minimum voltage threshold according to the charging request voltage range.

[0046] Exemplarily, the master station 100 obtains the charging request voltage range of the inverter 200 according to the number and model of each slave station 300, and determines the minimum value in the charging request voltage range as the charging request minimum voltage threshold.

[0047] It can be understood that when the slave station 300 is a battery pack, and the battery pack includes battery cells, the method also includes: determining the operating voltage and redundant voltage range of each battery cell according to the model of the battery cell; determining the charging request voltage range according to the operating voltage, redundant voltage range and the number of each battery cell.

[0048] Exemplarily, the master station 100 determines that the working voltage of the battery cell is 3.2V according to the model of the battery cell. If there are 16 battery cells connected in series in a battery pack, the total working voltage of the battery pack is 51.2V. When the battery cell is working, the actual voltage will fluctuate slightly compared to the working voltage. The fluctuation value is called the redundant voltage range. The redundant voltage range is determined according to the model of the battery cell. For a large-capacity battery cell, the voltage value in the redundant voltage range can be set to be relatively large, and for a small-capacity battery cell, the voltage value in the redundant voltage range can be set to be relatively small. For example, for a small-capacity battery cell, the redundant voltage range can be set to 0-0.2V, and the charging request voltage range is 51.0V-51.4V.

[0049] It is understood that the multiple cells of the battery pack can be connected in series, and the model and quantity of the cells of each battery pack can be the same. When the model and data of the cells of the battery pack are the same, the charging request voltage range of the inverter can be determined according to the model and quantity of the cells of one of the battery packs.

[0050] See also Figure 3 , step S200 includes: step S201-step S203, which are described in detail below.

[0051] Step S201, determining a target voltage value according to a target voltage range.

[0052] In this embodiment, the current voltages in the target voltage range may be sorted, and a current voltage may be determined as an initial voltage value according to the sorting result, and the target voltage value may be determined in combination with the initial voltage value.

[0053] See also Figure 4 , step S201 includes:

[0054] Step S2011 , determining an initial voltage value according to the sorting result of the current voltages of some or all slave stations 300 .

[0055] Exemplarily, the target voltage range includes the current voltages of some or all slave stations 300 , and the current voltages corresponding to the slave stations 300 are compared to determine the maximum voltage value of all the current voltages, and the maximum voltage value is used as the initial voltage value.

[0056] Step S2012 , determining a target voltage value according to the initial voltage value and a preset voltage offset range of the slave station 300 .

[0057] It can be understood that there is an offset between the actual output voltage of the slave station 300 and the detected current voltage, and the preset voltage offset range represents the voltage offset range between the actual output voltage of the slave station 300 and the detected current voltage, and the preset voltage offset range is related to the rated voltage of the slave station 300. For example, when the rated voltage of the slave station 300 is 48V, the preset voltage offset range is 1-500mV, and when the rated voltage of the slave station 300 is 400V, the preset voltage offset range is 0.1-2V, which is not limited here. Therefore, the target voltage value determined according to the initial voltage value and the preset voltage offset range can be more consistent with the actual voltage situation of the slave station 300.

[0058] See also Figure 5 , step S2012 includes:

[0059] Step S20121, determining a target offset voltage value according to a preset voltage offset range.

[0060] For example, if the rated voltage of the slave station 300 is 48V, the preset voltage offset range is 1-500mV, and the master station 100 determines 500mV as the target offset voltage value from 1-500mV.

[0061] Step S20122, subtract the target offset voltage value from the initial voltage value to obtain the target voltage value.

[0062] Exemplarily, the preset voltage offset is a positive value, such as 500mV. It can be understood that since the target voltage value is obtained by subtracting the target offset voltage value from the initial voltage value, the target voltage value will be smaller than the current voltage of some slave stations 300. For example, when the maximum voltage value among the current voltages of all slave stations 300 is used as the initial voltage value, the corresponding target voltage value is obtained by subtracting the target offset voltage value from the maximum voltage value. In other embodiments, the second largest voltage value among the current voltages of all slave stations 300 can also be used as the initial voltage value, and the target offset voltage value is subtracted from the second largest voltage value to obtain the target voltage value. Alternatively, the median of the voltage value can also be used as the initial voltage value, and the target offset voltage value is subtracted from the median of the voltage value to obtain the target voltage value. In this way, the target voltage value can be determined in a variety of ways, which can be more in line with the actual voltage situation of the slave station 300.

[0063] It can be understood that when the charging request current is 0, in order to suppress the current of the charging current between the inverter and each slave station, and to avoid the target charging voltage output by the inverter to the slave station according to the charging request voltage being too small, which causes an overvoltage fault on the energy storage side of the inverter, the master station 100 needs to ensure that the target charging request voltage is greater than or equal to the charging request minimum voltage threshold, and needs to ensure that the target charging request voltage is less than the target voltage value. Therefore, the master station 100 needs to compare the magnitude relationship between the current charging request voltage, the target voltage value and the charging request minimum voltage threshold, and dynamically adjust the charging request voltage according to the magnitude relationship. When analyzing the magnitude relationship between the current charging request voltage, the target voltage value and the charging request minimum voltage threshold, it can be divided into two situations. The first is the situation where the target voltage value is less than or equal to the charging request minimum voltage threshold, and step S202 is performed. The second is the situation where the target voltage value is greater than the charging request minimum voltage threshold, and step S203 is performed.

[0064] Step S202 : if the target voltage value is less than or equal to the minimum charging request voltage threshold, then determining the target charging request voltage according to the target voltage value and the minimum charging request voltage threshold.

[0065] In this embodiment, if the target voltage value is less than or equal to the charging request minimum voltage threshold, the charging request minimum voltage threshold is determined as the target charging request voltage.

[0066] It can be understood that when the target voltage value is less than or equal to the minimum voltage threshold of the charging request, the master station 100 determines the minimum voltage threshold of the charging request as the target charging request voltage. On the one hand, it can ensure that the target charging voltage output by the inverter 200 to the slave station 300 will be less than the current voltage of some slave stations 300 (these slave stations 300 are the target slave stations 301), and can suppress the charging current of the charging circuit between the inverter 200 and the target slave station 301 until the charging current of the charging circuit between the inverter 200 and the target slave station 301 becomes 0. On the other hand, it ensures that the target charging voltage output by the inverter 200 to other slave stations 300 will not be too small, and will not cause an overvoltage fault on the energy storage side of the inverter 200.

[0067] Step S203: if the target voltage value is greater than the charging request minimum voltage threshold, determining the charging request voltage according to the target voltage value, the current charging request voltage and the charging request minimum voltage threshold.

[0068] When the target voltage value is greater than the minimum charging request voltage threshold, the target charging request voltage needs to be dynamically adjusted in combination with the current charging request voltage determined by the SOP algorithm. Therefore, it is also necessary to further dynamically adjust the charging request voltage in combination with the current charging request voltage, the minimum charging request voltage threshold and the target voltage value.

[0069] In one embodiment, dynamically adjusting the charging request voltage according to the current charging request voltage, the target voltage value and the charging request minimum voltage threshold includes:

[0070] If the charging request minimum voltage threshold < the target voltage value < the current charging request voltage, the target voltage value is determined as the target charging request voltage;

[0071] If the charging request minimum voltage threshold value is less than the current charging request voltage and less than the target voltage value, the current charging request voltage is determined as the target charging request voltage;

[0072] If the current charging request voltage is less than the charging request minimum voltage threshold value and less than the target voltage value, the charging request minimum voltage threshold value is determined as the target charging request voltage.

[0073] In this embodiment, if the current charging request voltage determined by the SOP algorithm is greater than the target voltage value, the charging voltage provided by the inverter 200 to the slave station 300 may be greater than the current voltage of all slave stations 300, resulting in the inability to suppress the charging current of the charging circuit between the inverter 200 and the slave station 300 from becoming 0. Therefore, it is necessary to lower the charging voltage provided by the inverter 200 to the slave station 300, that is, by lowering the charging request voltage sent by the master station 100 to the inverter 200, so as to achieve the purpose of lowering the charging voltage provided by the inverter 200 to the slave station 300.

[0074] Specifically, the target voltage value is determined as the target charging request voltage, and the inverter 200 provides the target charging voltage to the slave station 300 according to the target charging request voltage. At this time, the target charging voltage is close to the target charging request voltage. For example, if the target charging request voltage is 5V, the target charging voltage output by the inverter 200 may be 5.01V or 4.98V. It can be understood that, ideally, the target charging voltage provided by the inverter 200 to the slave station 300 is equal to the target charging request voltage. However, due to the electrical characteristics of the inverter 200, in actual situations, there is a slight gap between the target charging voltage and the charging request voltage. It can be understood that since the target charging voltage is less than the current voltage of some slave stations (i.e., the target slave station 301), the charging current of the charging circuit between the inverter 200 and the target slave station 301 will be suppressed until the charging current of the charging circuit between the inverter 200 and the target slave station 301 becomes 0. For other slave stations, if their current voltage is lower than the target charging voltage, the inverter 200 will still charge the remaining slave stations 300 until the current voltage of the remaining slave stations 300 increases to be higher than the target charging voltage and the inverter 200 stops charging them.

[0075] In this embodiment, if the current charging request voltage determined by the SOP algorithm is less than the target voltage value, the charging voltage provided by the inverter 200 to the slave station 300 according to the current charging request voltage may be lower than the current voltage of some slave stations (i.e., the target slave station 301), thereby suppressing the charging current of the charging circuit between the inverter 200 and the target slave station 301. At this time, the current charging request voltage is determined as the target charging request voltage. At this time, the master station 100 allows the inverter 200 to still provide the corresponding charging voltage to the slave station 300 according to the current charging request voltage, and the inverter 200 does not need to be adjusted.

[0076] In this embodiment, in order to avoid overvoltage of the energy storage terminal voltage of the inverter 200, the target charging voltage output by the inverter 200 to the slave station 300 cannot be lower than the minimum voltage threshold of the charging request. Therefore, when the current charging request voltage is less than the minimum voltage threshold of the charging request, the current charging request needs to be adjusted to the minimum voltage threshold of the charging request. Specifically, the minimum voltage threshold of the charging request is determined as the target charging request voltage, and the inverter 200 provides the slave station 300 with a target charging voltage according to the minimum voltage threshold of the charging request. The target charging voltage is less than the current voltage of some slave stations (i.e., the target slave station 301), thereby suppressing the charging current of the charging circuit between the inverter 200 and the target slave station 301, and avoiding overvoltage of the target slave station 301. At this time, for the remaining slave stations whose current voltage is less than the target charging voltage, due to the existence of the small current charging phenomenon, the inverter 200 will still charge them. However, as the power of the remaining slave stations increases, the current voltage of the remaining slave stations will also gradually increase until their current voltage is greater than the target charging voltage, and the inverter 200 will stop charging the remaining slave stations.

[0077] In one embodiment, the charging control method further includes: obtaining a charging request current, and if the charging request current is within a preset charging current range of the slave station, executing a step of determining a target voltage range according to a current voltage of each slave station.

[0078] It can be understood that when the current charging request current determined by the SOP algorithm is within the preset charging current range, the step of determining the target voltage range according to the current voltage of each slave station is executed, that is, entering steps S100-S300, that is, starting the process of dynamically adjusting the charging request voltage, suppressing the charging current of the charging circuit between the inverter 200 and the slave station 300, so as to achieve the inverter 200 to stop charging some or all of the slave stations, and avoid overvoltage of some or all of the slave stations 300. It can be understood that when the charging request current is not within the preset charging current range, the step of determining the target voltage range according to the current voltage of each slave station is not executed, and the master station 100 sends a normal charging request voltage to the inverter 200, wherein the normal charging request voltage is determined by the SOP algorithm.

[0079] Exemplarily, the preset charging current range may be a current interval or a current value. For example, if the preset charging current range is 0-10mA, when the charging request current is 0, the step of determining the target voltage range according to the current voltage of each slave station is performed; when the charging request current is 11mA, the master station 100 sends a normal charging request voltage to the inverter 200. For another example, if the preset charging current range is 0, if the charging request current is 0, the step of determining the target voltage range according to the current voltage of each slave station is performed; if the charging request current is 10mV, the master station 100 sends a normal charging request voltage to the inverter 200.

[0080] In this way, the SOP algorithm control is performed in combination with the charging request current and the charging request voltage, and the charging request voltage is rationally controlled comprehensively to suppress the charging current of the charging circuit between the inverter 200 and part or all of the slave stations 300, thereby avoiding overvoltage of part or all of the slave stations 300.

[0081] In this embodiment, the master station 100 can be a BMS, the slave station 300 can be a battery pack, and the BMS, the battery pack and the inverter can constitute a home energy storage system. When the BMS adopts the charging control method, the charging current of the charging circuit between the inverter 200 and the battery pack can be suppressed, thereby avoiding overvoltage of the battery pack and disconnection of the charging circuit between the inverter 200 and the battery pack, ensuring that the home energy storage system will not shut down due to disconnection of the charging circuit between the inverter 200 and the battery pack, and ensuring the normal operation of the home energy storage system. The control process of the BMS adopting the charging control method will not affect the normal operation of the BMS, and it is convenient to adapt to BMSs of more manufacturers. Whether the charging and discharging circuit of the BMS adopts a contactor structure or a field effect tube structure, it can be adapted, thereby improving the adaptability of the BMS. The charging control method has no special requirements for the BMS and the inverter 200, will not affect the current SOP strategy of the BMS, and will not be affected by the different charging and discharging circuits of the BMS. It has strong adaptability to the inverter 200. The inverter 200 has two modes during the charging process: 1. When the charging request current is 0, it automatically switches to the discharge state; 2. When the charging request current is 0, it does not automatically switch to the discharge state. The inverters in these two modes can be adapted to the charging control method provided in this embodiment. The battery pack is allowed to discharge immediately after being fully charged, and the battery pack is also allowed to be fully charged and stored for a long time after being fully charged. The battery pack can be a lithium battery pack to better protect the lithium battery and prevent it from being in a high voltage state for a long time, which delays the battery life.

[0082] The charging control method provided in this embodiment determines the target voltage range according to the current voltage of each slave station 300; obtains the target charging request voltage according to the target voltage range and the current charging request voltage; sends the target charging request voltage to the inverter 200, so that the inverter 200 outputs the target charging voltage to each slave station 300 according to the target charging request voltage, and suppresses the charging current of the charging circuit between the inverter 200 and the target slave station 301. In this way, the charging current of the charging circuit between the inverter and the slave station can be suppressed by dynamically adjusting the charging request voltage, thereby avoiding the small current charging phenomenon of the charging circuit between the inverter 200 and the slave station 300, thereby avoiding overvoltage of the slave station 300 and improving the life and performance of the slave station 300.

[0083] The energy storage system provided by the embodiment of the present invention can implement the steps of the charging control method described in the above embodiment to achieve the corresponding technical effects. To avoid repetition, they are not described here.

[0084] The present application also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the charging control method provided in the above embodiment is implemented. The computer-readable storage medium may include, but is not limited to, various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0085] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or the flow diagram, and the combination of boxes in the structure diagram and / or the flow diagram, can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0086] In addition, the functional modules or units in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0087] If the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions for an electronic device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0088] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A charging control method, characterized in that: Applied to a master station, the master station is electrically connected to an inverter and at least one slave station respectively, and the inverter is also electrically connected to each of the slave stations respectively, and the method includes: Determining a target voltage range according to a current voltage of each of the slave stations; Acquire a target charging request voltage according to the target voltage range and a current charging request voltage; The target charging request voltage is sent to the inverter so that the inverter outputs the target charging voltage to each of the slave stations according to the target charging request voltage, thereby suppressing the charging current of the charging circuit between the inverter and the target slave station, wherein the target slave station is a slave station among the slave stations whose current voltage is greater than the target charging voltage.

2. The charging control method according to claim 1, characterized in that: The method further comprises: Acquire a charging request voltage range of the inverter according to the number and model of each of the slave stations, and determine a charging request minimum voltage threshold according to the charging request voltage range; The obtaining the target charging request voltage according to the target voltage range and the current charging request voltage includes: Determining a target voltage value according to the target voltage range; If the target voltage value is less than or equal to the charging request minimum voltage threshold, determining the target charging request voltage according to the target voltage value and the charging request minimum voltage threshold; If the target voltage value is greater than the charging request minimum voltage threshold, the charging request voltage is determined according to the target voltage value, the current charging request voltage and the charging request minimum voltage threshold.

3. The charging control method according to claim 2, characterized in that: The determining the target charging request voltage according to the target voltage value and the charging request minimum voltage threshold comprises: The charging request minimum voltage threshold is determined as the target charging request voltage.

4. The charging control method according to claim 2, characterized in that: The step of determining the charging request voltage according to the target voltage value, the current charging request voltage and the charging request minimum voltage threshold comprises: If the charging request minimum voltage threshold value is less than the target voltage value and less than the current charging request voltage, the target voltage value is determined as the target charging request voltage; If the charging request minimum voltage threshold value is less than the current charging request voltage and less than the target voltage value, the current charging request voltage is determined as the target charging request voltage; If the current charging request voltage is less than the charging request minimum voltage threshold value and less than the target voltage value, the charging request minimum voltage threshold value is determined as the target charging request voltage.

5. The charging control method according to claim 2, characterized in that: The target voltage range includes a part or all of the current voltages of the slave stations, and determining the target voltage value according to the target voltage range includes: Determining an initial voltage value according to the sorting result of the current voltages of some or all of the slave stations; The target voltage value is determined according to the initial voltage value and a preset voltage offset range of the slave station.

6. The charging control method according to claim 5, characterized in that: The determining the target voltage value according to the initial voltage value and a preset voltage offset range of the slave station includes: Determining a target offset voltage value according to the preset voltage offset range; The target voltage value is obtained by subtracting the target offset voltage value from the initial voltage value.

7. The charging control method according to claim 2, characterized in that: The slave station includes a battery pack, and the battery pack includes battery cells. The step of obtaining the charging request voltage range of the inverter according to the number and model of each of the slave stations includes: Determine the operating voltage and redundant voltage range of each battery cell according to the model of the battery cell; The charging request voltage range is determined according to the operating voltage, the redundant voltage range and the number of each of the battery cells.

8. The charging control method according to any one of claims 1 to 7, characterized in that: The method further comprises: A charging request current is obtained, and if the charging request current is within a preset charging current range of the slave station, the step of determining a target voltage range according to a current voltage of each of the slave stations is performed.

9. An energy storage system, characterized in that: The system comprises: a master station, an inverter and at least one slave station; the master station is electrically connected to the inverter and each of the slave stations respectively; the inverter is also electrically connected to each of the slave stations respectively; The master station is used to determine a target voltage range according to the current voltage of each of the slave stations; obtain a target charging request voltage according to the target voltage range and the current charging request voltage; send the target charging request voltage to the inverter, so as to output the target charging voltage to each of the slave stations through the inverter according to the target charging request voltage, thereby suppressing the charging current of the charging circuit between the inverter and the target slave station, and the target slave station is a slave station among the slave stations whose current voltage is greater than the target charging voltage.

10. A computer storage medium, characterized in that: The device stores a computer program, which, when executed on a processor, implements the charging control method according to any one of claims 1 to 8.

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