Battery charging and discharging control method and system, energy storage inverter and medium

Abstract

The embodiment of the invention provides a battery charging and discharging control method and system, an energy storage inverter and a medium, the method is applied to the energy storage inverter, and the battery working state and the battery state parameter of each battery module are obtained; determining a reference battery module and other battery modules except the reference battery module from the plurality of battery modules according to the battery working state and the battery state parameter of each battery module; determining a parameter difference value between the battery state parameter of the reference battery module and the battery state parameter of each other battery module; and acquiring a preset working control curve, and controlling the working parameters of the other battery modules according to the preset working control curve and the parameter difference values so as to reduce or maintain the parameter difference values. Therefore, the difference of the battery state parameters among the battery modules can be prevented from continuously increasing when the multiple battery modules work, and the dynamic balance of the working states among the multiple battery modules is effectively guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of battery charge and discharge control, and in particular to a battery charge and discharge control method, system, energy storage inverter and medium. Background Art

[0002] Energy storage inverters are devices that convert direct current stored in batteries into alternating current. Multiple battery modules are usually installed inside them to facilitate the application of inverters in renewable energy systems such as solar photovoltaic systems and wind power systems. In current energy storage inverters, when the number of battery modules is large, it is difficult for existing energy storage inverters to maintain a dynamic balance between the battery modules, and the balancing control capability for multiple battery modules is poor. Summary of the invention

[0003] Based on the above problems, in order to solve the problem that it is difficult for existing energy storage inverters to maintain a dynamic balanced working state between various battery modules, the embodiments of the present application provide a battery charging and discharging control method, system, energy storage inverter and medium.

[0004] The embodiments of the present application disclose the following technical solutions: In a first aspect, an embodiment of the present application provides a battery charge and discharge control method, which is applied to an energy storage inverter, wherein the energy storage inverter includes a plurality of battery modules; the method includes: Obtaining the battery operating state and battery state parameters of each of the battery modules; Determining a reference battery module and other battery modules except the reference battery module from the plurality of battery modules according to the battery operating status of each battery module and the battery status parameter; Determine parameter differences between the battery state parameters of the reference battery module and the battery state parameters of each of the other battery modules; A preset working control curve is obtained, and the working parameters of each of the other battery modules are controlled according to the preset working control curve and each of the parameter differences to reduce or maintain each of the parameter differences.

[0005] In a possible implementation, the battery state parameter includes: battery SOC; the battery operating state includes: charging state and discharging state; The step of determining a reference battery module from the plurality of battery modules according to the battery operating status of each battery module and the battery status parameter comprises: When the battery operating state of each of the battery modules is the charging state, determining the battery module with the smallest battery SOC as the reference battery module; When the battery operating state of each of the battery modules is the discharge state, the battery module with the largest battery SOC is determined as the reference battery module.

[0006] In a possible implementation, the operating parameter includes: charging power; the parameter difference is an SOC difference; The controlling the operating parameters of each of the other battery modules according to the preset operating control curve and each of the parameter differences includes: When the battery working state of each of the battery modules is the charging state, determining the charging power control coefficient of the other battery modules corresponding to each of the SOC differences according to the preset working control curve; determining the charging power of each of the other battery modules according to each of the charging power control coefficients and the charging power of the reference battery module; The charging process of each of the other battery modules is controlled according to the charging power of each of the other battery modules.

[0007] In a possible implementation, the operating parameter includes: discharge power; the parameter difference is an SOC difference; The controlling the operating parameters of each of the other battery modules according to the preset operating control curve and each of the parameter differences includes: When the battery working state of each of the battery modules is the discharging state, determining the discharge power control coefficient of the other battery modules corresponding to each of the SOC differences according to the preset working control curve; Determining the discharge power of each of the other battery modules according to each of the discharge power control coefficients and the discharge power of the reference battery module; The discharge process of each of the other battery modules is controlled according to the discharge power of each of the other battery modules.

[0008] In a possible implementation, after determining a reference battery module from the plurality of battery modules according to the battery operating status of each of the battery modules and the battery status parameter, the method further includes: When the battery operating state of each battery module is the discharge state, determining the battery module whose battery SOC is less than a preset first threshold as a module to be charged; According to the rated output power of the reference battery module and the real-time output power of the reference battery module, the reference battery module is controlled to charge the module to be charged.

[0009] In a possible implementation, charging the module to be charged according to the rated output power of the reference battery module and the real-time output power of the reference battery module includes: When the difference between the rated output power and the real-time output power of the reference battery module is not less than a preset second threshold, the reference battery module is controlled to charge the module to be charged based on the difference between the rated output power and the real-time output power.

[0010] In a possible implementation, the energy storage inverter includes a plurality of DC / DC converters; The plurality of battery modules are connected to the plurality of DC / DC converters one-to-one, and each battery module is charged or discharged through the connected DC / DC converter.

[0011] In a second aspect, an embodiment of the present application provides a battery charge and discharge control system, which is applied to an energy storage inverter, wherein the energy storage inverter includes a plurality of battery modules; the system includes: An acquisition module, used to acquire the battery working state and battery state parameters of each battery module; A first determining module, configured to determine a reference battery module and other battery modules except the reference battery module from the plurality of battery modules according to the battery operating status of each battery module and the battery status parameter; A second determination module, used to determine parameter differences between the battery state parameters of the reference battery module and the battery state parameters of each of the other battery modules; The control module is used to obtain a preset working control curve, and control the working parameters of each of the other battery modules according to the preset working control curve and each of the parameter differences, so as to reduce or maintain each of the parameter differences.

[0012] In a third aspect, an embodiment of the present application provides an energy storage inverter, which is used to implement any possible battery charging and discharging control method in the first aspect.

[0013] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any possible battery charge and discharge control method in the first aspect.

[0014] Compared with the prior art, the present application has the following beneficial effects: The embodiments of the present application provide a battery charge and discharge control method, system, energy storage inverter and medium. In the method, by obtaining the battery working state and battery state parameters of each battery module, the difference in working parameters between different battery modules can be accurately reflected, so as to provide a basis for the control of multiple batteries. Subsequently, the reference battery module and other battery modules other than the reference battery module are determined from multiple battery modules through the battery state parameters and battery working state of each battery module, and the working parameters of each battery module are controlled according to the difference in battery state parameters between the reference battery module and each battery module, as well as the pre-set working control curve, so that accurate control of multiple battery modules can be completed. Among them, since the working control curve characterizes the corresponding relationship between the battery state parameter difference and the working parameters, by calculating the difference in battery state parameters between the reference battery module and other battery modules, the working parameters of other battery modules except the reference battery module can be controlled through the battery state parameter difference between the battery module and the reference battery module, thereby reducing or maintaining the parameter difference between other battery modules and the reference battery module, preventing the battery state parameter difference between each battery module from continuing to increase, and effectively ensuring the dynamic balance of the working states between multiple battery modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 A connection diagram of a multi-channel DC / DC converter in the prior art provided in an embodiment of the present application; Figure 2 A method based on the embodiment of the present application is provided Figure 1 Control block diagram of the circuit structure; Figure 3 A schematic diagram of a circuit structure of a battery charging and discharging control method provided in an embodiment of the present application; Figure 4 A corresponding embodiment provided in this application Figure 3 Control block diagram of the circuit structure; Figure 5 A flowchart of a battery charging and discharging control method provided in an embodiment of the present application; Figure 6 A schematic diagram of a preset working control curve provided in an embodiment of the present application; Figure 7 A schematic diagram of a reference battery module determination process provided in an embodiment of the present application; Figure 8 A flowchart of another battery charging and discharging control method provided in an embodiment of the present application; Fig. 9 A flowchart of another battery charging and discharging control method provided in an embodiment of the present application; Fig.10 A flowchart of another battery charging and discharging control method provided in an embodiment of the present application; Fig.11 A schematic diagram of the structure of a battery charging and discharging control system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of this application more clear, the following is a further detailed description of this application in combination with specific embodiments and with reference to the accompanying drawings. It should be noted that the embodiments described in the embodiments of this application are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0018] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "include" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0019] As described above, in current energy storage inverters, when the number of battery modules is large, it is difficult for existing energy storage inverters to maintain a dynamically balanced working state between each battery module, and the balancing control capability for multiple battery modules is poor. Research has found that in current energy storage inverters, the DC bus of the inverter is often connected to multiple DC / DCs (Direct Current to Direct Current Converters) for controlling multiple battery modules. Under this connection mode, multiple DC / DCs often work in a current-sharing manner. When multiple DC / DCs work in a current-sharing manner, each DC / DC converter will bear the same current load, and it is impossible to ensure that the working state of each battery module is in a dynamically balanced working state.

[0020] For details, please refer to Figure 1 and Figure 2 . Figure 1 A connection diagram of a multi-channel DC / DC converter in the prior art provided in an embodiment of the present application is shown in FIG. Figure 2 A method based on the embodiment of the present application is provided Figure 1 The control block diagram of the circuit structure. Figure 2 In the control block diagram shown, BusRef represents the reference voltage of the DC bus, and Gbus represents a controller module, which is used to generate a current control instruction I_Bat_Cmd according to the reference voltage and the actual voltage.

[0021] As shown in the figure, Figure 1 The two DC / DC modules in the circuit are connected to the same battery string Battery total. Since the two DC / DC modules share the same battery string, the working mode of the two DC / DC modules is current sharing control. Under this connection condition, the charging power or discharging power is evenly distributed to the two DC / DC modules. Figure 1 The control block diagram of the wiring method is as follows Figure 2 As shown, since the two DC / DC modules share a DC bus control loop, the I_Bat_Cmd1 and I_Bat_Cmd2 input to the two DC / DC modules are the same, that is, the charging power or discharging power output by the two DC / DC modules is the same.

[0022] However, in actual application scenarios, there may be certain differences in the brands and battery status parameters of different battery strings. Taking the battery status parameter SOC as an example, when the SOC of each battery module is different, if the charging power or discharging power set for each battery string is the same, and there are differences in the SOC of each battery module, such a control method will cause the battery status parameters (such as SOC) of each battery module to differ more and more, thereby affecting the normal operation of the energy storage inverter.

[0023] In order to solve the above problems, the embodiment of the present application provides a battery charge and discharge control method, system, energy storage inverter and medium. In the method, by obtaining the battery working state and battery state parameters of each battery module, the difference in working parameters between different battery modules can be accurately reflected, so as to provide a basis for the control of multiple batteries. Subsequently, the reference battery module and other battery modules other than the reference battery module are determined from multiple battery modules through the battery state parameters and battery working state of each battery module, and the working parameters of each battery module are controlled according to the difference in battery state parameters between the reference battery module and each battery module, and the pre-set working control curve, so that the precise control of multiple battery modules can be completed. Among them, since the working control curve characterizes the corresponding relationship between the battery state parameter difference and the working parameter, by calculating the difference in battery state parameters between the reference battery module and other battery modules, the working parameters of other battery modules other than the reference battery module can be controlled through the difference in battery state parameters between the battery module and the reference battery module, thereby reducing or maintaining the parameter difference between other battery modules and the reference battery module, preventing the battery state parameter difference between each battery module from continuing to increase, and effectively ensuring the dynamic balance of the working state between multiple battery modules.

[0024] First, in order to facilitate understanding of the technical solution provided by the embodiment of the present application, the exemplary circuit structure diagram and the corresponding control block diagram of the embodiment of the present application are first introduced: See also Figure 3 and Figure 4 , Figure 3 A circuit diagram of a battery charging and discharging control method provided in an embodiment of the present application is shown in FIG. Figure 4 A corresponding embodiment provided in this application Figure 3 Control block diagram of the circuit structure.

[0025] like Figure 3 and Figure 4 As shown, each battery module has a corresponding DC / DC module. The battery module is connected to the DC / DC converter one-to-one, and the two DC modules do not form a loop together. Each battery module controls its charging and discharging through its correspondingly connected DC / DC converter.

[0026] Among them, the control module Gbus outputs the current control instruction I_Bat_Cmd for different battery modules by presetting the K value in the working control curve. I_Bat_Max represents the maximum charging power or maximum discharging power carried by the battery module, and I_Bat_Min represents the minimum charging power or minimum discharging power carried by the battery module. The calculation method of I_Bat_Max and I_Bat_Min based on K is specifically introduced in the manual.

[0027] It should be noted that Figure 3 and Figure 4 Only two battery modules are shown as an example of the battery charge and discharge control method in the embodiment of the present application, and the use scenario is not limited to two battery modules. As the number of battery modules increases, the corresponding DC / DC modules will also increase accordingly, which will not be described in detail in this embodiment.

[0028] Next, the battery charging and discharging control method provided in the embodiment of the present application will be introduced in conjunction with the specific embodiment drawings.

[0029] See also Figure 5 , which is a flow chart of a battery charging and discharging control method provided in an embodiment of the present application, and specifically includes the following steps: S101: Obtain the battery operating state and battery state parameters of each battery module.

[0030] First, the execution subject of the battery charge and discharge control method of the present invention can be a battery management system, and the BMS (Battery Management System) in the energy storage inverter obtains the battery working status and corresponding battery status parameters of each battery module in the energy storage inverter. Among them, the battery status parameters are used to characterize the working status and battery characteristics of the battery, such as battery SOC, battery capacity, battery backup time, etc.

[0031] In this embodiment, the battery working state of the battery module includes a charging state and a discharging state. In order to ensure the load balance of the energy storage inverter and prevent overload or underload in one of the circuits, when each battery module in the inverter has a certain SOC, each battery module will enter the discharging state together to provide power to the energy storage inverter, or enter the charging state together to store power. In actual application scenarios, the BMS can obtain the battery working status of each battery module through the CAN communication bus. The battery status parameters corresponding to each battery module can also be obtained through corresponding sensors, such as voltage sensors, current sensors, and temperature sensors, etc., which will not be described in detail in this embodiment.

[0032] S102: Determine a reference battery module and other battery modules except the reference battery module from the plurality of battery modules according to the battery operating status and the battery status parameters of each battery module.

[0033] After determining the actual battery operating status of each battery module and the corresponding battery status parameters, it is necessary to determine a reference battery module and other battery modules except the reference battery module from the multiple battery modules.

[0034] From the description of the related technology in the foregoing, it can be seen that in the related technology, when controlling the charging and discharging process of multiple battery modules, the charging power or discharging power of the multiple battery modules is controlled to be the same because the current is shared. When there are differences between the battery modules themselves, the same charging power or discharging power will cause the differences in the battery state parameters between the battery modules to become larger and larger, thereby affecting the operating stability of the energy storage inverter.

[0035] Therefore, through the battery state parameters and battery working status of each battery module, a reference battery module can be determined from multiple battery modules, and the difference between the reference battery module and other battery modules can be understood based on the reference battery module, so as to facilitate the subsequent targeted control of different battery modules. For example, when the battery state parameter is SOC, by comparing the SOC of the reference battery module with the SOC of other battery modules, the SOC difference between different battery modules and the reference battery module can be understood, so as to reasonably control the charging power or discharging power of each battery module, so as to prevent the SOC difference between each battery module and the reference battery module from increasing continuously, and realize the dynamic balance of multiple battery modules.

[0036] S103: Determine parameter differences between the battery state parameters of the reference battery module and the battery state parameters of each of the other battery modules.

[0037] After determining the reference battery module and other battery modules except the reference battery module, the parameter differences between other battery modules and the reference battery module are calculated, which can effectively understand the differences in battery status parameters between each battery module and the reference battery module, so as to facilitate the subsequent individual control of the charging and discharging process of each battery module based on the specific differences between each battery module and the reference battery module.

[0038] S104: Obtain a preset working control curve, and control the working parameters of each of the other battery modules according to the preset working control curve and each of the parameter differences, so as to reduce or maintain each of the parameter differences.

[0039] Correspondingly, after determining the parameter difference in battery state parameters between the reference battery and other battery modules, a preset working control curve is obtained, and based on the preset working control curve and the parameter difference between each battery module and the reference battery module, the working parameters of other battery modules except the reference battery module are controlled, thereby performing targeted control on the working parameters of each battery module based on the difference in state parameters between each battery module and the reference battery module, so as to reduce or maintain the parameter difference between other battery modules and the reference battery module, prevent the difference in state parameters between multiple battery modules from increasing continuously, and ensure the dynamic balance of the working state of each battery module in the multi-battery module.

[0040] The preset working control curve is used to represent the corresponding relationship between the battery state parameter difference and the working parameter. For example, taking the battery state parameter as SOC and the working parameter as charging power or discharging power as an example, see Figure 6 A schematic diagram of a preset working control curve disclosed, such as Figure 6 As shown, the ordinate represents the control coefficient K between the battery module and the reference battery module, and the abscissa SOC_Diff represents the absolute value of the difference between the reference battery SOC and the battery module SOC.

[0041] Assume that the SOC of the reference battery module is 100% and the SOC of one of the battery modules is 50%, and the SOC difference between the two is 50%. Figure 6 In the curve diagram, the control coefficient K=5.0 corresponding to the 50% SOC difference. At this time, the reference battery module is set to be in a discharge state, and its discharge power is 100W. At this time, since the control coefficient K=5.0, the discharge power of the reference battery module should be 5 times that of the battery module, that is, the output power of the corresponding battery module should be: 100W / 5=20W, and the reference battery module with a larger SOC bears more discharge power to reduce the output burden of the other battery module.

[0042] Under this control logic, by controlling the reference battery module to bear more discharge power and adaptively adjusting the discharge power borne by other battery modules, the parameter difference (SOC difference) between other battery modules and the reference battery module can be effectively reduced or maintained, so that the parameter difference between other battery modules and the reference battery module no longer increases, thereby ensuring the dynamic balance of the working state of each battery module.

[0043] In addition, you can refer to the aforementioned Figure 4 In actual application scenarios, in order to control the gain of battery modules other than the reference battery module within a reasonable range, when controlling the current control instruction through the K value in the preset control curve, the K value can be appropriately adjusted to ensure the smoothness of the gain.

[0044] The specific control method is as follows: I_Bat_Max = I_Bat_Cmd * K / (K + 1); I_Bat_Min = I_Bat_Cmd / (K+1); When the working state of each battery module is the discharge state, during discharge, the battery module with a larger SOC is assigned I_Bat_Max, and the battery module with a smaller SOC is assigned I_Bat_Min. Correspondingly, when the working state of each battery module is the charge state, the battery module with a smaller SOC is assigned I_Bat_Max, and the battery module with a larger SOC is assigned I_Bat_Min.

[0045] It can be seen that under this control logic, the battery power of different battery modules is determined by the parameter difference between itself and the reference battery module, so that the charging and discharging control of multiple battery modules can be more in line with actual application needs and application scenarios, ensuring the operating stability of the energy storage inverter. As can be seen from the foregoing, in the battery charge and discharge control method provided in the embodiment of the present application, the battery state parameter may be the actual battery SOC, and the battery operating state of the battery module may be the charging state and the discharging state. Next, the determination process of the reference battery module in the above step S102 will be introduced in conjunction with the specific embodiment drawings.

[0046] See also Figure 7 , which is a schematic diagram of a reference battery module determination process provided by an embodiment of the present application, specifically comprising the following steps: S201: When the battery operating state is the charging state, determine the battery module with the smallest battery SOC as the reference battery module.

[0047] As can be seen from the foregoing, the working states of multiple battery modules in the energy storage inverter are the same, and the working state of the battery modules can be a charging state or a discharging state. When the battery working state of multiple battery modules is a charging state, in order to ensure that the working states between the battery modules are in a dynamic balance state, it is necessary to ensure that the battery module with the smallest battery SOC replenishes a certain amount of electric energy in time. Therefore, when the battery working state of multiple battery modules is a charging state, the reference battery module is the battery module with the smallest battery SOC.

[0048] S202: When the battery operating state is the discharging state, determine the battery module with the largest battery SOC as the reference battery module.

[0049] Similarly, when the battery operating state of each battery module is a discharge state, it is necessary to determine the battery module with the largest battery SOC as the reference battery module, so that the reference battery module can provide the maximum discharge power, thereby providing buffer time for other battery modules, preventing multiple battery modules from being overloaded due to excessive discharge power at the same time, and ensuring the dynamic balance of the working states between the battery modules.

[0050] Next, in conjunction with the drawings of specific embodiments, the process of controlling the operating parameters of each other battery module according to the preset operating control curve and each parameter difference in the above step S104 when the battery operating state of each battery module is the charging state will be introduced.

[0051] See also Figure 8 , which is a flow chart of another battery charge and discharge control method provided in an embodiment of the present application, specifically comprising the following steps: S301: When the battery operating state of each of the battery modules is the charging state, determining the charging power control coefficient of the other battery modules corresponding to each of the SOC differences according to the preset operating control curve.

[0052] As can be seen from the foregoing, in the process of controlling the operating parameters of each battery module, it is necessary to determine the corresponding control coefficient from the preset operating control curve based on the parameter difference between each battery module and the reference battery module, so as to control the operating parameters of the battery module.

[0053] Therefore, when the battery working state of each battery module is the charging state, the charging power of other battery modules needs to be controlled. According to the SOC difference between each battery module except the reference battery module and the reference battery module, the charging power control coefficient corresponding to each battery module can be determined separately.

[0054] For example, for the first battery module other than the reference battery module, the SOC of the reference battery module is set to 0% and the SOC of the first battery module is set to 100%. Then the SOC difference between the two is 100%-0%=100%. Under this condition, 100% is the parameter difference between the first battery module and the reference battery module. Based on the parameter difference of 100% in Figure 6 The charging power control coefficient is determined in the preset working control curve shown, and the corresponding charging power control coefficient can be determined to be 10.0.

[0055] It should be noted that in actual application scenarios, when calculating the SOC difference between the reference battery module and other battery modules, the absolute value of the difference between the two can be used as the parameter difference, or the actual calculated value can be used as the parameter difference. This embodiment does not limit this.

[0056] S302: Determine the charging power of each of the other battery modules according to each of the charging power control coefficients and the charging power of the reference battery module.

[0057] After determining the charging power control coefficients corresponding to other battery modules, the charging power of the reference battery module itself and the charging power control coefficients corresponding to each battery module are calculated to determine the charging power of each battery module except the reference battery module.

[0058] For example, for the first battery module and the second battery module other than the reference battery module, assuming that the charging power of the reference battery module is 100W, the corresponding charging power control coefficients of the first battery module and the second battery module are 10 and 5 respectively. Therefore, the charging power of the first battery module = 100 / 10 = 10W; the charging power of the second battery module is 100 / 5 = 20W.

[0059] In particular, the charging power of the reference battery module may be directly obtained and determined by the BMS, and the charging power of the reference battery module may also be set according to the actual current load condition of the energy storage inverter, which is not limited in this embodiment.

[0060] S303: Controlling the charging process of each of the other battery modules according to the charging power of each of the other battery modules.

[0061] In this way, the charging power of each other battery module can be determined through the parameter difference between the other battery modules and the reference battery module and the preset working control curve, and the charging process of each other battery module can be controlled through the charging power of each other battery module.

[0062] Based on the above Figure 8 In the description, the control method of the charging power of other battery modules except the reference battery module is described when the battery working state of each battery module is the charging state. Next, the process of controlling the working parameters of each other battery module according to the preset working control curve and each parameter difference when the battery working state of each battery module is the discharging state will be introduced in combination with the specific embodiment drawings.

[0063] See also Fig. 9 , which is a flow chart of another battery charging and discharging control method provided in an embodiment of the present application, specifically comprising the following steps: S401: When the battery operating state of each of the battery modules is the discharging state, determining the discharge power control coefficient of the other battery modules corresponding to each of the SOC differences according to the preset operating control curve.

[0064] Similar to the control logic when the batteries of each battery module are in a charging state, when the batteries of each battery module are in a discharging state, the specific discharge power control coefficient of each battery module can be determined individually based on the SOC difference between each battery module except the reference battery module and the reference battery module.

[0065] For example, for the third battery module other than the reference battery module, the SOC of the reference battery module is set to 100% and the SOC of the third battery module is set to 0%. Then the SOC difference between the two is 100%-0%=100%. Under this condition, 100% is the parameter difference between the third battery module and the reference battery module. Figure 6 The discharge power control coefficient is determined in the preset working control curve shown, and the corresponding charging power control coefficient can be determined to be 10.0.

[0066] S402: Determine the discharge power of each of the other battery modules according to each of the discharge power control coefficients and the discharge power of the reference battery module.

[0067] Accordingly, when determining the discharge power control coefficients of other battery modules, the discharge powers of other battery modules can be respectively determined based on the discharge power of the reference battery module.

[0068] For example, for the third battery module and the fourth battery module other than the reference battery module, assuming that the discharge power of the reference battery module is 80W, the discharge power control coefficients of the third battery module and the fourth battery module are 8 and 5, respectively. Thus, the discharge power of the third battery module = 80 / 8 = 10W; the discharge power of the second battery module is 80 / 5 = 16W.

[0069] S403: controlling the discharge process of each of the other battery modules according to the discharge power of each of the other battery modules.

[0070] In this way, the discharge power of each other battery module can be determined through the parameter difference between the other battery modules and the reference battery module and the preset working control curve, and the discharge process of each other battery module can be controlled through the discharge power of each other battery module.

[0071] In the battery charge and discharge control scenario of the present application, when the battery working state is the discharge state, the working state of all battery modules in the energy storage inverter will be adjusted to the discharge state. When there is a battery module with a very small SOC among multiple battery modules, if the battery module is still adjusted to the discharge state, it may cause losses to the battery module. In this case, since the discharge power of the reference battery module is the maximum power among the multiple battery modules, the actual load condition of the energy storage inverter can be considered to control a part of the discharge power of the reference battery module to be used for charging the battery module with a very small SOC, so that the battery module has a certain amount of power reserve, thereby ensuring the stability of the operation of the energy storage inverter.

[0072] Next, the countermeasures taken to solve the above problems will be introduced in conjunction with the drawings of specific embodiments.

[0073] See also Fig.10 , which is a flow chart of another battery charging and discharging control method provided in an embodiment of the present application, specifically comprising the following steps: S501: When the battery operating state of each battery module is the discharging state, determine the battery module whose battery SOC is less than a preset first threshold as a module to be charged.

[0074] When the working state of the battery is a discharge state, the BMS monitors the SOC of each battery module, and when there is a battery module whose battery SOC is less than a preset first threshold, the battery module is determined as a module to be charged.

[0075] S502: Controlling the reference battery module to charge the module to be charged according to the rated output power of the reference battery module and the real-time output power of the reference battery module.

[0076] Since the real-time output power of the reference battery module is determined by the real-time load of the energy storage inverter, by comparing the rated output power and the real-time output power of the reference battery module, it can be determined whether the reference battery module is in a fully loaded state at this time. When the difference between the rated output power and the real-time output power of the reference battery module is not less than the preset second threshold, it indicates that the reference battery module has a certain amount of power idle at this time and is not in a fully loaded state. Therefore, at this time, the real-time output power of the reference battery module can be adjusted to the rated output power to provide electric energy supplement for the module to be charged, thereby preventing the electric energy reserve of the module to be charged from being too low and improving the operating stability of the energy storage inverter.

[0077] The embodiment of the present application provides a battery charge and discharge control method, system, energy storage inverter and medium. In the method, by obtaining the battery working state and battery state parameters of each battery module, the difference in working parameters between different battery modules can be accurately reflected, so as to provide a basis for the control of multiple batteries. Subsequently, the reference battery module and other battery modules other than the reference battery module are determined from multiple battery modules through the battery state parameters and battery working state of each battery module, and the working parameters of each battery module are controlled according to the difference in battery state parameters between the reference battery module and each battery module, and the pre-set working control curve, so that the precise control of multiple battery modules can be completed. Among them, since the working control curve characterizes the corresponding relationship between the battery state parameter difference and the working parameter, by calculating the difference in battery state parameters between the reference battery module and other battery modules, the working parameters of other battery modules other than the reference battery module can be controlled through the difference in battery state parameters between the battery module and the reference battery module, thereby reducing or maintaining the parameter difference between other battery modules and the reference battery module, preventing the battery state parameter difference between each battery module from continuing to increase, and effectively ensuring the dynamic balance of the working state between multiple battery modules.

[0078] A battery charge and discharge control system provided in an embodiment of the present application is introduced below. The battery charge and discharge control system described below and the battery charge and discharge control method described above can refer to each other.

[0079] See also Fig.11 , which is a schematic diagram of the structure of a battery charging and discharging control system provided in an embodiment of the present application, specifically including the following modules: An acquisition module, used to acquire the battery working state and battery state parameters of each battery module; A first determining module, configured to determine a reference battery module and other battery modules except the reference battery module from the plurality of battery modules according to the battery operating status of each battery module and the battery status parameter; A second determination module, used to determine parameter differences between the battery state parameters of the reference battery module and the battery state parameters of each of the other battery modules; The control module is used to obtain a preset working control curve, and control the working parameters of each of the other battery modules according to the preset working control curve and each of the parameter differences, so as to reduce or maintain each of the parameter differences.

[0080] The embodiment of the present application also provides an energy storage inverter, which is used to implement any possible battery charging and discharging control method in the above embodiments.

[0081] Based on the same inventive concept, corresponding to any of the above-mentioned embodiments and methods, an embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable the computer to execute the battery charging and discharging control method described in any of the above embodiments.

[0082] The computer-readable media of the embodiments of the present application include permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, read-only compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device.

[0083] The computer instructions stored in the storage medium of the above embodiment are used to enable the computer to execute the battery charging and discharging control method described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0084] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same and similar parts between the various embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for methods, systems, energy storage inverters and media, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiments. The methods, systems, energy storage inverters and media described above are merely schematic, in which the units described as separate components may or may not be physically separated, and the components indicated as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without creative work.

[0085] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A battery charging and discharging control method, characterized in that: Applied to an energy storage inverter, the energy storage inverter includes a plurality of independent battery modules; the method includes: Obtaining the battery operating state and battery state parameters of each of the battery modules; Determining a reference battery module and other battery modules except the reference battery module from the plurality of battery modules according to the battery operating status of each battery module and the battery status parameter; Determine parameter differences between the battery state parameters of the reference battery module and the battery state parameters of each of the other battery modules; A preset working control curve is obtained, and the working parameters of each of the other battery modules are controlled according to the preset working control curve and each of the parameter differences to reduce or maintain each of the parameter differences.

2. The method according to claim 1, characterized in that The battery state parameters include: battery SOC; the battery working state includes: charging state and discharging state; The step of determining a reference battery module from the plurality of battery modules according to the battery operating status of each battery module and the battery status parameter comprises: When the battery operating state of each of the battery modules is the charging state, determining the battery module with the smallest battery SOC as the reference battery module; When the battery operating state of each of the battery modules is the discharge state, the battery module with the largest battery SOC is determined as the reference battery module.

3. The method according to claim 2, characterized in that The working parameters include: charging power; the parameter difference is the SOC difference; The controlling the operating parameters of each of the other battery modules according to the preset operating control curve and each of the parameter differences includes: When the battery working state of each of the battery modules is the charging state, determining the charging power control coefficient of the other battery modules corresponding to each of the SOC differences according to the preset working control curve; determining the charging power of each of the other battery modules according to each of the charging power control coefficients and the charging power of the reference battery module; The charging process of each of the other battery modules is controlled according to the charging power of each of the other battery modules.

4. The method according to claim 2, characterized in that The working parameters include: discharge power; the parameter difference is the SOC difference; The controlling the operating parameters of each of the other battery modules according to the preset operating control curve and each of the parameter differences includes: When the battery working state of each of the battery modules is the discharging state, determining the discharge power control coefficient of the other battery modules corresponding to each of the SOC differences according to the preset working control curve; Determining the discharge power of each of the other battery modules according to each of the discharge power control coefficients and the discharge power of the reference battery module; The discharge process of each of the other battery modules is controlled according to the discharge power of each of the other battery modules.

5. The method according to claim 2, characterized in that: After determining a reference battery module from the plurality of battery modules according to the battery operating status of each battery module and the battery status parameter, the method further comprises: When the battery operating state of each battery module is the discharge state, determining the battery module whose battery SOC is less than a preset first threshold as a module to be charged; According to the rated output power of the reference battery module and the real-time output power of the reference battery module, the reference battery module is controlled to charge the module to be charged.

6. The method according to claim 5, characterized in that The step of charging the module to be charged according to the rated output power of the reference battery module and the real-time output power of the reference battery module comprises: When the difference between the rated output power and the real-time output power of the reference battery module is not less than a preset second threshold, the reference battery module is controlled to charge the module to be charged based on the difference between the rated output power and the real-time output power.

7. The method according to claim 1, characterized in that The energy storage inverter includes a plurality of DC / DC converters; The plurality of battery modules are connected to the plurality of DC / DC converters one-to-one, and each battery module is charged or discharged through the connected DC / DC converter.

8. A battery charge and discharge control system, characterized in that: Applied to an energy storage inverter, the energy storage inverter includes a plurality of independent battery modules; the system includes: An acquisition module, used to acquire the battery working state and battery state parameters of each battery module; A first determining module, configured to determine a reference battery module and other battery modules except the reference battery module from the plurality of battery modules according to the battery operating status of each battery module and the battery status parameter; A second determination module, used to determine parameter differences between the battery state parameters of the reference battery module and the battery state parameters of each of the other battery modules; The control module is used to obtain a preset working control curve, and control the working parameters of each of the other battery modules according to the preset working control curve and each of the parameter differences, so as to reduce or maintain each of the parameter differences.

9. An energy storage inverter, characterized in that: The energy storage inverter is used to implement the battery charging and discharging control method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the battery charge and discharge control method described in any one of claims 1 to 7 is implemented.

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