Energy storage battery modules and parallel control method therefor, DC / DC converter and related device

Abstract

Provided in the present application are energy storage battery modules and a parallel control method therefor, a DC / DC converter and a related device, wherein a plurality of energy storage battery modules are connected in parallel on the same direct-current bus. The method comprises: for at least one energy storage battery module, by using the current sampling value of a target output parameter and SOC information of the energy storage battery module, determining a target voltage reference value of the energy storage battery module, wherein the target output parameter is an output current or an output power; on the basis of the target voltage reference value of the energy storage battery module and a sampling value of the voltage of a direct-current bus, regulating the voltage of the direct-current bus, so as to obtain a given value of the target output parameter; and on the basis of the given value of the target output parameter, calculating a drive signal of a DC / DC converter corresponding to the energy storage battery module. By means of the present application, energy storage battery modules can externally exhibit voltage source characteristics when connected in parallel; moreover, the effect of power distribution can be realized without needing to rely on communications to transmit SOC information.

Description

Energy storage battery module, parallel control method thereof, DC / DC converter and related device

[0001] The present application claims priority to the domestic application filed on September 24, 2024, with the China Patent Office and with application number 2024113414511 and with the title "Energy storage battery module, parallel control method thereof, DC / DC converter and related device", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of energy storage batteries, in particular to an energy storage battery module, a parallel control method thereof, a DC / DC converter and related device. BACKGROUND

[0003] In recent years, the installed power of energy storage systems has been increasing year by year. With the increase of the total capacity of the entire energy storage system, the system capacity of the battery module required to be configured will also increase, and multiple energy storage battery modules are often connected in parallel to the DC bus architecture. However, the State of Charge (SOC) of each energy storage battery module is different when connected in parallel to the same DC bus, and how to consider the change of SOC for power distribution becomes a big difficulty.

[0004] At present, for the power distribution of a parallel system, one way is to set up a master and several slaves, the master uses voltage loop control, and the slaves use current loop control to share the current command according to the SOC. However, this method needs to rely on high-speed communication between the master and the slaves to meet the demand for fast power response. Moreover, the energy storage battery module using current loop control presents the characteristics of a current source rather than a voltage source, making it difficult to realize the true restoration of the battery operating characteristics.

[0005] Therefore, the present application provides an energy storage battery module, a parallel control method thereof, a DC / DC converter and related device to improve the related art. SUMMARY

[0006] The purpose of the present application is to provide an energy storage battery module, a parallel control method thereof, a DC / DC converter and related device, which do not need to rely on communication to transfer the SOC information of the energy storage battery module, so that the energy storage battery module exhibits voltage source characteristics when connected in parallel.

[0007] The purpose of the present application is achieved by adopting the following technical solutions:

[0008] In a first aspect, the present application provides a parallel control method of an energy storage battery module, multiple energy storage battery modules being connected in parallel to the same DC bus, the method comprising:

[0009] For at least one energy storage battery module, a target voltage reference value of the energy storage battery module is determined by using a current sampling value of a target output parameter of the energy storage battery module and SOC information of the energy storage battery module; the target output parameter is output current or output power;

[0010] Based on the target voltage reference value of the energy storage battery module and a sampling value of a DC bus voltage, the DC bus voltage is adjusted to obtain a given value of the target output parameter;

[0011] According to the given value of the target output parameter, a drive signal of a corresponding DC / DC converter of the energy storage battery module is calculated.

[0012] In some embodiments, the determination of the target voltage reference value of the energy storage battery module by using the current sampling value of the target output parameter of the energy storage battery module and the SOC information of the energy storage battery module comprises:

[0013] According to the current sampling value of the target output parameter, the target voltage reference value is determined by using a corresponding relationship between a voltage reference value and a sampling value of the target output parameter;

[0014] The corresponding relationship includes a target corresponding parameter, and a parameter value of the target corresponding parameter is determined according to the SOC information of the energy storage battery module.

[0015] In some embodiments, the charging direction is taken as a positive direction of the target output parameter, and the corresponding relationship satisfies the following conditions:

[0016] When the sampling value of the target output parameter is within a target output parameter value range of the energy storage battery module, the voltage reference value increases with the increase of the sampling value of the target output parameter; or, when the sampling value of the target output parameter is greater than a maximum value of the target output parameter value range, the target voltage reference value is kept as a maximum value of a target voltage value range of the energy storage battery module; or, when the sampling value of the target output parameter is less than a minimum value of the target output parameter value range, the target voltage reference value is kept as a minimum value of the target voltage value range.

[0017] The target output parameter value range and the target voltage value range of the energy storage battery module are determined according to the SOC information of the energy storage battery module.

[0018] In some embodiments, the target output parameter is output current, and the target corresponding parameter includes a discharging slope and a charging slope; when the sampling value of the target output parameter is within the target output parameter value range, the corresponding relationship is represented as follows:

[0019] wherein, Vref represents the voltage reference value, Vn represents the no-load voltage, Io represents the sampling value of the output current, k_dis(SOC) represents the discharging slope, k_char(SOC) represents the charging slope, I_dis_max represents the maximum discharging current, and I_char_max represents the maximum charging current.

[0020] In some embodiments, the discharging slope decreases as the SOC value increases, and / or the charging slope increases as the SOC value increases.

[0021] In some embodiments, the adjusting the DC bus voltage based on the target voltage reference value of the energy storage battery module and the sampling value of the DC bus voltage to obtain the given value of the target output parameter comprises:

[0022] In the case that the target voltage reference value does not match the sampling value of the DC bus voltage:

[0023] When the sampling value of the DC bus voltage is within the target voltage value range, the given value of the target output parameter is determined according to the sampling value of the DC bus voltage and the corresponding relationship; or, when the sampling value of the DC bus voltage is greater than the maximum value of the target voltage value range, the given value of the target output parameter is determined as the maximum value of the target output parameter value range; or, when the sampling value of the DC bus voltage is less than the minimum value of the target voltage value range, the given value of the target output parameter is determined as the minimum value of the target output parameter value range.

[0024] In a second aspect, the present application provides a DC / DC converter applied to an energy storage battery module, the DC / DC converter comprising a voltage controller, a driving module and a main circuit.

[0025] The voltage controller is configured to execute any of the above methods to calculate a driving signal.

[0026] The driving module is configured to receive the driving signal from the voltage controller and drive the main circuit.

[0027] In a third aspect, the present application provides an energy storage battery module, comprising at least one battery cell and any of the above DC / DC converters.

[0028] In a fourth aspect, the present application provides an energy storage system, comprising a DC bus and a plurality of energy storage battery modules as described above.

[0029] In a fifth aspect, the present application provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement any of the above methods.

[0030] In a sixth aspect, the present application provides a chip for implementing any of the above methods.

[0031] The present application provides an energy storage battery module and a parallel control method thereof, a DC / DC converter and related devices. For the energy storage battery modules connected in parallel on the same DC bus, the sampling value of the target output parameter (for example, output current or output power) and the SOC information are used to determine the target voltage reference value. Based on the target voltage reference value and the sampling value of the DC bus voltage, the DC bus voltage is adjusted to obtain the given value of the target output parameter. According to the given value of the target output parameter, the driving signal of the corresponding DC / DC converter of the energy storage battery module is calculated, so as to realize the parallel control of the energy storage battery module. The above embodiments make the energy storage battery module exhibit voltage source characteristics when connected in parallel, and can accurately restore the actual working characteristics of the battery. Moreover, the SOC information of the energy storage battery module does not need to be transmitted by communication, and the effect of power distribution can be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0032] The present application will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0033] FIG. 1 is a structural schematic diagram of a parallel type energy storage system according to an embodiment of the present application.

[0034] FIG. 2 is a flow schematic diagram of a parallel control method of an energy storage battery module according to an embodiment of the present application.

[0035] FIG. 3 is a schematic diagram of a whole control loop of a DC / DC converter according to an embodiment of the present application.

[0036] FIG. 4 is a schematic diagram of the corresponding relationship between the voltage reference value and the sampling value of the target output parameter according to an embodiment of the present application.

[0037] FIG. 5 is a schematic diagram of a droop curve according to an embodiment of the present application.

[0038] FIG. 6a is a schematic diagram of current distribution of battery modules with different SOC under a discharge condition (none of the three battery modules reaches the maximum discharge current) according to an embodiment of the present application.

[0039] FIG. 6b is a schematic diagram of current distribution of battery modules with different SOC under a discharge condition (one battery module reaches the maximum discharge current) according to an embodiment of the present application.

[0040] FIG. 6c is a schematic diagram of current distribution of battery modules with different SOC under discharging condition (all the three battery modules reach the maximum discharging current) according to an embodiment of the present application.

[0041] FIG. 7 is a structural block diagram of a computer device according to an embodiment of the present application. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person skilled in the art without creative work fall within the scope of protection of the present application.

[0043] In the description of the embodiments of the present application, it should be understood that the terms "first", "second" are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0044] Referring to FIG. 1, FIG. 1 is a structural schematic diagram of a parallel type energy storage system according to an embodiment of the present application.

[0045] In recent years, the installed power of energy storage systems has been increasing year by year. With the increase of the total capacity of the entire energy storage system, the system capacity of the battery modules required to be configured will also increase, and multiple energy storage battery modules are often connected in parallel to the DC bus architecture. A parallel type energy storage system is shown in FIG. 1, and the battery modules in the figure are energy storage battery modules. However, the battery state of charge (SOC) of each energy storage battery module is different when connected in parallel to the same DC bus. How to consider the change of SOC to distribute the charging and discharging power becomes a big difficulty.

[0046] At present, for the power distribution of a parallel system, one way is to set a master and several slaves. The master uses voltage loop control, and the slaves use current loop control to share the current command according to the SOC. However, this method needs high-speed communication between the master and the slaves to meet the demand of fast power response. Moreover, the energy storage battery modules using current loop control show the characteristics of current source rather than voltage source, and it is difficult to realize the true restoration of the battery operating characteristics.

[0047] Referring to FIG. 2 and FIG. 3, FIG. 2 is a flow diagram of a parallel control method of an energy storage battery module according to an embodiment of the present application, and FIG. 3 is a diagram of a whole control loop of a DC / DC converter according to an embodiment of the present application.

[0048] To improve the related art, the parallel control method of an energy storage battery module according to an embodiment of the present application is provided, and a plurality of energy storage battery modules are connected in parallel to the same DC bus. The method comprises steps S101-S103.

[0049] In step S101, for at least one energy storage battery module, a target voltage reference value of the energy storage battery module is determined by using a current sampling value of a target output parameter of the energy storage battery module and SOC information, wherein the target output parameter is output current or output power.

[0050] In step S102, based on the target voltage reference value of the energy storage battery module and a sampling value of a DC bus voltage, the DC bus voltage is adjusted to obtain a given value of the target output parameter.

[0051] In step S103, a driving signal of a DC / DC converter corresponding to the energy storage battery module is calculated according to the given value of the target output parameter.

[0052] In the above embodiment, the energy storage battery module comprises one or more battery cells, for example. In some embodiments, the energy storage battery module can be built-in with a DC / DC converter. That is, the DC / DC converter corresponding to the energy storage battery module can be built-in in the energy storage battery module, or can be separately arranged and have a communication function with the energy storage battery module, which is not limited in the above embodiment. The energy storage battery module built-in with the DC / DC converter can realize independent operation of different energy storage battery modules, improve the problem of series mismatch or parallel adaptation, reduce the mutual influence between the energy storage battery modules, and is extremely competitive in practical application.

[0053] In some embodiments, the SOC information (e.g., the SOC value) can be represented by a value between 0 and 1, or can also be represented by a percentage. The target voltage reference value can change in each control period until the voltage regulation reaches a steady state. The DC bus voltage is regulated, for example, closed-loop regulated, and when the closed-loop regulation (also referred to as closed-loop control) reaches a steady state, the target voltage reference value matches the sampled value of the DC bus voltage. The target voltage reference value matches the sampled value of the DC bus voltage, for example, means that the target voltage reference value and the sampled value of the DC bus voltage are exactly the same, or can also mean that the absolute value of the difference between the target voltage reference value and the sampled value of the DC bus voltage is less than a target difference value, or can also mean that the ratio of the absolute value of the difference between the target voltage reference value and the sampled value of the DC bus voltage to the target voltage reference value is less than a target ratio value. The target difference value and the target ratio value can be selected according to actual needs, and the above embodiments do not limit this.

[0054] In some embodiments, the target output parameter can be an output current. In other embodiments, the target output parameter can be an output power.

[0055] The related method relies on high-speed communication between the master and the slave, and in addition, the related method uses current loop control, which is difficult to truly restore the battery working characteristics of the energy storage battery module. The above embodiments enable multiple energy storage battery modules to automatically adjust the power output of each energy storage battery module according to the SOC information without relying on high-speed communication between the master and the slave in the case of parallel connection, thereby improving the overall efficiency and stability of the energy storage system. Moreover, by using voltage loop control for the energy storage battery module, the battery working characteristics of the energy storage battery module can be truly restored. Specifically, first, the target voltage reference value of the energy storage battery module is determined according to the current sampled value of the target output parameter of the energy storage battery module and the SOC information of the energy storage battery module, and then the DC bus voltage is regulated by the voltage regulation mechanism. Without relying on communication between different energy storage battery modules, each energy storage battery module can independently adjust the output power according to its own SOC information, so that the energy storage battery module with a high SOC discharges more power in the discharging condition, and the energy storage battery module with a low SOC charges more power in the charging condition, thereby ensuring the voltage stability and power balance of the overall energy storage system.

[0056] The method makes the energy storage battery module exhibit voltage source characteristics when in parallel, can accurately restore the actual working characteristics of the battery, and improves the response speed and stability of the energy storage system. The energy storage battery module can maintain the stability of the DC bus voltage whether it is single or multiple in parallel. Moreover, without relying on communication to transmit the SOC information of the energy storage battery module, the effect of power distribution can be achieved, thereby realizing the SOC balance between different energy storage battery modules. Each energy storage battery module only needs to obtain its own SOC information, which greatly improves the accuracy and real-time performance of power distribution.

[0057] In some embodiments, the determining the target voltage reference value of the energy storage battery module by using the current sampling value of the target output parameter of the energy storage battery module and the SOC information can include: determining the target voltage reference value according to the current sampling value of the target output parameter by using a corresponding relationship between the voltage reference value and the sampling value of the target output parameter; wherein the corresponding relationship contains a target corresponding parameter, and a parameter value of the target corresponding parameter is determined according to the SOC information of the energy storage battery module.

[0058] In the above embodiments, the corresponding relationship refers to a mathematical or empirical relationship between the sampling value of the target output parameter and the voltage reference value, which reflects the voltage requirement that the energy storage battery module should reach at a certain SOC level to achieve the predetermined output. The corresponding relationship can be represented by a corresponding formula or a corresponding model. The target corresponding parameter refers to a parameter contained in the corresponding relationship, such as a formula parameter in the corresponding formula or a model parameter in the corresponding model. The corresponding formula can be a linear formula (such as a corresponding droop curve) or a nonlinear formula. The corresponding model in the above embodiments is not limited, which can be a model based on deep learning, for example.

[0059] The above embodiments determine the target voltage reference value of the battery module participating in voltage regulation by analyzing the current sampling value of the target output parameter of the energy storage battery module and the SOC information, and using a dynamic adjustment method. Specifically, the target voltage reference value is dynamically adjusted according to the current sampling value of the target output parameter by using a pre-established corresponding relationship between the voltage reference value and the target output parameter. The corresponding relationship is set according to the SOC information of the energy storage battery module, so that the energy storage battery module can automatically match the appropriate target voltage reference value at different SOC levels. By real-time calculation and dynamic adjustment of the target voltage reference value, the response speed and control accuracy of the energy storage battery module in parallel operation are improved, thereby optimizing the charge and discharge efficiency of the system. By using the method of combining SOC information and target output parameter, the battery module can automatically adjust the output according to the current state, reduce the imbalance phenomenon caused by the difference in SOC, realize the balance of the SOC of different energy storage battery modules, and improve the safety and stability of the system.

[0060] In one specific application scenario, it is observed that, with the charging direction as the positive direction of the target output parameter, for one of the battery modules, the sampled value of the DC bus voltage and the sampled value of the target output parameter satisfy the following external characteristic: when the sampled value of the DC bus voltage is within the target voltage value range of the energy storage battery module, the sampled value of the DC bus voltage increases with the increase of the sampled value of the target output parameter; or, when the sampled value of the DC bus voltage is greater than the maximum value of the target voltage value range, the sampled value of the target output parameter remains the maximum value under the charging condition (i.e., the maximum value of the target output parameter value range); or, when the sampled value of the DC bus voltage is less than the minimum value of the target voltage value range, the sampled value of the target output parameter remains the maximum value under the discharging condition (i.e., the minimum value of the target output parameter value range); wherein the target voltage value range and the target output parameter value range of the energy storage battery module are determined according to the SOC information of the energy storage battery module.

[0061] It should be noted that the target voltage reference value and the sampled value of the DC bus voltage are not the same physical meaning. Taking the output current as an example of the target output parameter, for one of the battery modules (in this paper, one battery module is equivalent to one battery module), only when the output current is within the upper and lower limits of the charging and discharging current (i.e., between the maximum discharging current and the maximum charging current), the sampled value of the DC bus voltage can match the target voltage reference value (achieve the effect of closed-loop control). When the output current of the battery module reaches the maximum discharging current, the sampled value of the DC bus voltage will be controlled by other modules that do not reach the maximum discharging current, and at this time the sampled value of the DC bus voltage can be lower than the target voltage reference value of the battery module. When the output current of the battery module reaches the maximum charging current, the sampled value of the DC bus voltage will be controlled by other modules that do not reach the maximum charging current, and at this time the sampled value of the DC bus voltage can be higher than the target voltage reference value of the battery module. It is equivalent to that the battery module reaches the upper limit of the voltage regulation capability (no longer participates in the subsequent voltage regulation), and the battery module remains at the maximum charging current or the maximum discharging current, and the remaining battery modules that do not reach the upper limit of the regulation capability are responsible for the stable control of the DC bus voltage.

[0062] That is, the above embodiments can perform voltage regulation on multiple energy storage battery modules connected in parallel to the same DC bus, and in actual applications, closed-loop regulation can be performed on all energy storage battery modules, or only on part of the energy storage battery modules (in which case, the part of the energy storage battery modules not participating in closed-loop regulation will remain at the upper limit of its voltage regulation capability, and the target output parameter will remain at the maximum or minimum value of the corresponding target output parameter value range). However, since all energy storage battery modules are connected in parallel to the same DC bus, the sampling values of the corresponding DC bus voltage of these energy storage battery modules are the same.

[0063] Referring to FIG. 4, FIG. 4 is a schematic diagram of the correspondence between a voltage reference value and a sampling value of a target output parameter according to an embodiment of the present application.

[0064] As shown in FIG. 4, in some embodiments, taking the charging direction as the positive direction of the target output parameter, the correspondence can satisfy the following conditions: when the sampling value of the target output parameter is within the target output parameter value range of the energy storage battery module, the voltage reference value increases with the increase of the sampling value of the target output parameter; or, when the sampling value of the target output parameter is greater than the maximum value of the target output parameter value range, the target voltage reference value remains the maximum value of the target voltage value range of the energy storage battery module; or, when the sampling value of the target output parameter is less than the minimum value of the target output parameter value range, the target voltage reference value remains the minimum value of the target voltage value range; wherein the target output parameter value range and the target voltage value range of the energy storage battery module are determined according to the SOC information of the energy storage battery module.

[0065] In theory, the sampling value of the target output parameter will not exceed its target output parameter value range, for example, the output current of a single battery module will not exceed its charge and discharge current limit. However, considering the influence of sampling error, when the sampling value of the target output parameter exceeds the target output parameter value range, the target voltage reference value can also have a determined calculation result for performing the following voltage regulation.

[0066] In the above embodiments, the charging direction refers to the direction of current flow during charging of the energy storage battery module, which can be defined as the positive direction. Alternatively, in other embodiments, the discharging direction can be defined as the positive direction, which is not limited in the present application. The positive direction of the charging direction as the target output parameter refers to the positive direction of the output current or the output power being consistent with the charging direction. The target voltage value range is a voltage threshold interval defined according to the SOC information of the energy storage battery module, which has a corresponding maximum value and a minimum value. The target output parameter value range is an output parameter threshold interval defined according to the SOC information of the energy storage battery module, which has a corresponding maximum value and a minimum value. When the target output parameter is the output current, the target output parameter value range is the target output current output range, the maximum value of which is the maximum charging current and the minimum value of which is the maximum discharging current. Similarly, when the target output parameter is the output power, the target output parameter value range is the target output power output range, the maximum value of which is the maximum charging power and the minimum value of which is the maximum discharging power.

[0067] The above embodiments define the charging direction as the positive direction of the target output parameter and specify the dynamic corresponding relationship characteristics between the voltage reference value and the sampling value of the target output parameter. By establishing the dynamic corresponding relationship between the voltage reference value and the target output parameter, the charging and discharging control strategy of the energy storage battery module is optimized.

[0068] In actual applications, the positive direction of the port current (i.e., the output current) of each battery module (i.e., the energy storage battery module) is defined as charging. If n (n is a positive integer) battery modules are connected in parallel on the same DC bus, the external characteristics of each battery module are as follows.

[0069] The port voltage of the first battery module is controlled so that the port voltage v1 of the first battery module and the port current i1 of the battery module have a linear relationship, for example, a drooping curve. When the port voltage v1 is located in the corresponding target voltage value range (a function of SOC) of the battery module, the port voltage v1 and the port current i1 have a monotonically increasing relationship, i.e., the port voltage v1 increases with the increase of the port current i1; when the port voltage v1 is greater than the maximum value of the target voltage value range, the port current i1 remains the maximum charging current; when the port voltage v1 is less than the minimum value of the target voltage value range, the port current i1 remains the maximum discharging current.

[0070] The port voltage of the second battery module is controlled so that the port voltage v2 of the second battery module and the port current i2 of the battery module have a linear relationship, for example, a drooping curve. When the port voltage v2 is within the corresponding target voltage value range of the battery module (a function of SOC), the port voltage v2 and the port current i2 have a monotonically increasing relationship, that is, the port voltage v2 increases with the increase of the port current i2; when the port voltage v2 is greater than the maximum value of the target voltage value range, the port current i2 remains the maximum charging current; when the port voltage v2 is less than the minimum value of the target voltage value range, the port current i2 remains the maximum discharging current.

[0071] …

[0072] The port voltage of the nth battery module is controlled so that the port voltage vn of the nth battery module and the port current in of the battery module have a linear relationship, for example, a drooping curve. When the port voltage vn is within the corresponding target voltage value range of the battery module (a function of SOC), the port voltage vn and the port current in have a monotonically increasing relationship, that is, the port voltage vn increases with the increase of the port current in; when the port voltage vn is greater than the maximum value of the target voltage value range, the port current in remains the maximum charging current; when the port voltage vn is less than the minimum value of the target voltage value range, the port current in remains the maximum discharging current.

[0073] The above embodiments allocate power to each module by the SOC of each parallel module, so that the port voltages of each parallel module are equal and the output currents can be allocated according to the size of the SOC. The modulation of v1 and i1, v2 and i2, …, vn and in is such that when v1=v2=…=vn, the size relationship of i1, i2, …, in meets the requirement of equalization of different battery module SOCs, that is, in the charging condition, the absolute value size of i1, i2, …, in and the SOC value are inversely proportional, and in the discharging condition, the absolute value size of i1, i2, …, in and the SOC value are proportional.

[0074] In some embodiments, the target output parameter can be the output current, the target corresponding parameters can include the discharging slope k_dis(SOC) and the charging slope k_char(SOC), and when the sampling value of the target output parameter is within the target output parameter value range, the corresponding relationship can be represented as follows.

[0075] wherein Vref represents the voltage reference value, Vn represents the no-load voltage, Io represents the sampling value of the output current, k_dis(SOC) represents the discharging slope, k_char(SOC) represents the charging slope, I_dis_max represents the maximum discharging current, and I_char_max represents the maximum charging current.

[0076] In the above embodiments, the target output parameter is output current, the maximum value of the target output parameter value range corresponding thereto is the maximum charging current, and the minimum value of the target output parameter value range corresponding thereto is the maximum discharging current.

[0077] The discharging slope k dis (SOC) refers to the slope of a straight line formed by the voltage reference value (as the vertical axis) and the sampling value of the output current (as the horizontal axis) in the discharging process at a specific SOC. The charging slope k char (SOC) refers to the slope of a straight line formed by the voltage reference value (as the vertical axis) and the sampling value of the output current (as the horizontal axis) in the charging process at a specific SOC. The no-load voltage Vn refers to the voltage value of the energy storage battery module in the case of no load (i.e., the output current is zero). The sampling value of the output current Io is the output current value of the energy storage battery module monitored in real time, which is used to calculate and control the voltage reference value. The maximum discharging current is the maximum current value allowed by the energy storage battery module in the discharging process. The maximum charging current is the maximum current value allowed by the energy storage battery module in the charging process.

[0078] In actual applications, the target voltage value range and the target output parameter value range of different energy storage battery modules can be the same or different, which is not limited in the above embodiments.

[0079] In some embodiments, the discharging slope k dis (SOC) can decrease with the increase of the SOC value. In some embodiments, the charging slope k char (SOC) can increase with the increase of the SOC value.

[0080] In some embodiments, the discharging slope k dis (SOC) can be calculated in the following manner.

[0081] In some embodiments, the charging slope k char (SOC) can be calculated in the following manner.

[0082] wherein SOCmin represents the minimum value of the SOC, SOCmax represents the maximum value of the SOC, k dis (SOCmin) represents the maximum value of k dis (SOC) corresponding to SOCmin, k dis (SOCmax) represents the minimum value of k dis (SOC) corresponding to SOCmax, k char (SOCmax) represents the maximum value of k char (SOC) corresponding to SOCmax, and k char (SOCmin) represents the minimum value of k char (SOC) corresponding to SOCmin.

[0083] In some embodiments:

[0084] k_dis(SOCmin) = (Vn - Vmin) / I_dis_max,

[0085] k_dis(SOCmax) = β x k_dis(SOCmin).

[0086] In some embodiments:

[0087] k_char(SOCmax) = (Vmax - Vn) / I_char_max,

[0088] k_char(SOCmin) = β x k_char(SOCmax).

[0089] wherein Vmin represents the lowest voltage in discharging condition, Vmax is the highest voltage in charging condition, and β represents a slope fluctuation coefficient.

[0090] The slope fluctuation coefficient β represents the fluctuation degree between the maximum and minimum values of the slope. The above embodiments do not limit the slope fluctuation coefficient β, which may, for example, be 0.05, 0.1, 0.15, etc. In other embodiments, different slope fluctuation coefficients can be set for the discharging slope and the charging slope, which are not limited in the present application.

[0091] In some embodiments, Vmax, Vmin, I_dis_max and I_char_max can be set according to the design requirements of the DC / DC converter.

[0092] For example, the DC / DC converter built in each battery module adopts the control scheme shown in FIG. 3, and the calculation of the voltage reference value of each control cycle depends on the size of the current SOC and the sampling value of the output current. The input of the voltage controller is the calculated voltage reference value and the sampling value of the DC bus voltage. The DC bus voltage is adjusted by the voltage controller, and the output current given value is used to calculate the driving signal of the DC / DC converter. The above scheme calculates the voltage reference value by substituting the sampling value of the output current into the droop curve, and an alternative scheme is to calculate the voltage reference value by substituting the port power (i.e., the output power) into the droop curve (i.e., using the output power instead of the output current), which is different in the design of the horizontal coordinate of the droop curve. The schemes are similar, and the following only describes the method for formulating the droop curve for calculating the voltage reference value in the scheme of sampling the output current.

[0093] Referring to FIG. 5, FIG. 5 is a schematic diagram of a droop curve provided by an embodiment of the present application.

[0094] An example of the droop curve for calculating the voltage reference value is shown in FIG. 5. Wherein Io represents the sampled value of the port current (i.e., output current) of the battery module, it is stipulated herein that the discharging current is negative and the charging current is positive (i.e., the positive direction is in the charging direction). I_dis_max represents the maximum discharging current of the energy storage battery module, I_char_max represents the maximum charging current of the energy storage battery module, Vmax represents the upper limit of the voltage reference value (i.e., the maximum value of the target voltage value range), corresponding to the charging condition, and Vmin represents the lower limit of the voltage reference value (i.e., the minimum value of the target voltage value range), corresponding to the discharging condition. For example, the steps of establishing the droop curve and calculating the voltage reference value can be as follows.

[0095] S1: Determine the boundaries of the droop curve according to the design requirements of the DC / DC converter, i.e., the upper and lower limits of the voltage reference value Vmax and Vmin and the upper and lower limits of the charging and discharging current I_char_max and I_dis_max.

[0096] S2: Determine the slopes k_dis(SOC) and k_char(SOC) of the droop curve in the charging condition and the discharging condition according to the parameters in S1. The slope of the droop curve (including the discharging slope and the charging slope) is a function of SOC. The slope of the droop curve in the discharging condition is monotonically decreasing with respect to SOC, i.e., the higher the SOC value, the smaller the slope. The slope of the droop curve in the charging condition is monotonically increasing with respect to SOC, i.e., the higher the SOC value, the larger the slope. The maximum and minimum values of the slope can be determined according to the upper and lower limits of the voltage reference value and the upper and lower limits of the charging and discharging current.

[0097] It should be noted that the schematic diagram of the droop curve (i.e., FIG. 5) in this application is based on the stipulation of the positive direction of the charging and discharging current. If the stipulation of the positive direction of the charging and discharging current is opposite to this application, the FIG. 5 can be mirror flipped, which can be considered as the same or similar scheme as this application. The determination of the slope of the droop curve can achieve the equalization of different battery module SOCs as long as it meets the above basic principles. Herein, a specific calculation method is given as an example, and the specific details can be flexibly adjusted according to the actual scheme requirements.

[0098] Under the discharge condition, the maximum value of k_dis(SOC) corresponding to the minimum value of SOC (SOCmin) is k_dis(SOCmin), and k_dis(SOCmin) can be taken as (Vn-Vmin) / I_dis_max, wherein Vn is the no-load voltage, and the voltage reference value corresponding to the charging and discharging current of 0. The minimum value of k_dis(SOC) corresponding to the maximum value of SOC (SOCmax) is k_dis(SOCmax), and k_dis(SOCmax) can be taken as β×k_dis(SOCmin), wherein β is a slope fluctuation coefficient, and β=0.1 is taken. The calculation of k_dis(SOC) can be set as:

[0099] Under the charging condition, the maximum value of k_char(SOC) corresponding to the maximum value of SOC (SOCmax) is k_char(SOCmax), and k_char(SOCmax) can be taken as (Vmax-Vn) / I_char_max. The minimum value of k_char(SOC) corresponding to the minimum value of SOC (SOCmin) is k_char(SOCmin), and k_char(SOCmin) can be taken as β×k_char(SOCmin). The calculation of k_char(SOC) can be set as:

[0100] The voltage reference value boundary at different SOC is determined according to the slope of the droop curve and the upper and lower limits of the charging and discharging current. For any SOC, the lower boundary of the voltage reference value can be set as VL(SOC)=Vn-k_dis(SOC)×I_dis_max, and the upper boundary of the voltage reference value can be set as VH(SOC)=Vn+k_char(SOC)×I_char_max. The formula for calculating the voltage reference value Vref according to the droop curve is:

[0101] The sampling value of Io is substituted into the above formula, and the corresponding target voltage reference value can be calculated.

[0102] In some embodiments, the adjusting the DC bus voltage based on the target voltage reference value of the energy storage battery module and the sampled value of the DC bus voltage to obtain the given value of the target output parameter can include, in the case that the target voltage reference value does not match the sampled value of the DC bus voltage: when the sampled value of the DC bus voltage is within the target voltage value range, determining the given value of the target output parameter according to the sampled value of the DC bus voltage and the corresponding relationship; or, when the sampled value of the DC bus voltage is greater than the maximum value of the target voltage value range, determining the given value of the target output parameter as the maximum value of the target output parameter value range; or, when the sampled value of the DC bus voltage is less than the minimum value of the target voltage value range, determining the given value of the target output parameter as the minimum value of the target output parameter value range.

[0103] When the target output parameter is output current, the maximum value of the target output parameter value range is the maximum value in the charging condition, i.e., the maximum charging current, and the minimum value of the target output parameter value range is the maximum value in the discharging condition, i.e., the maximum discharging current. When the target output parameter is output power, the maximum value of the target output parameter value range is the maximum value in the charging condition, i.e., the maximum charging power, and the minimum value of the target output parameter value range is the maximum value in the discharging condition, i.e., the maximum discharging power. The maximum charging power and the maximum discharging power can be selected according to actual needs, for example, can be set according to the design requirements of related equipment.

[0104] With the above voltage droop control scheme, the battery modules with different SOC values exhibit the following external characteristics. The DC bus voltage is controlled by all the parallel battery modules, and each battery module exhibits voltage source characteristics. The setting of the droop curve slope can enable the battery modules that do not reach the charging and discharging current limit to allocate the total charging and discharging power demand on the DC bus according to the SOC. The application only takes the discharging condition as an example to describe the current allocation of battery modules with different SOC, and the charging condition is similar to the discharging condition, which will not be described here.

[0105] Referring to FIGS. 6a-6c, FIG. 6a is a schematic diagram of current allocation of battery modules with different SOC in a discharging condition (all three battery modules do not reach the maximum discharging current), FIG. 6b is a schematic diagram of current allocation of battery modules with different SOC in a discharging condition (one battery module reaches the maximum discharging current), and FIG. 6c is a schematic diagram of current allocation of battery modules with different SOC in a discharging condition (all three battery modules reach the maximum discharging current).

[0106] As shown in FIGS. 6a-6c, when the total discharging current on the DC bus gradually increases from zero, the DC bus voltage gradually decreases from the no-load voltage Vn, and the DC bus voltage is always controlled by the battery module that has not reached the current limit (the maximum discharging current in the discharging mode). As shown in FIG. 6a, if the three battery modules have not reached the discharging current limit (i.e., the maximum discharging current), the three battery modules all participate in closed-loop control, and the voltage reference value of each battery module matches the sampling value of the DC bus voltage in the steady state. The discharging current value (i.e., the given value of the output current) of each module is the current value corresponding to the intersection of the DC bus voltage value and the droop curve. It can be seen that the greater the SOC of the module, the smaller the discharging slope of the droop curve, and the greater the corresponding discharging current value, i.e., I1>I2>I3. As shown in FIG. 6b, if the total discharging current demand further increases, the DC bus voltage will further decrease, at which time the battery module with SOC = 1.0 first reaches the discharging current limit, and the discharging current no longer increases, and the voltage regulator reaches the saturation state and no longer participates in closed-loop control, while the discharging currents of the two battery modules with SOC = 0.8 and SOC = 0.3 can continue to increase, and these two battery modules still participate in closed-loop control. If the total discharging current demand further increases, the battery modules with SOC = 0.8 and SOC = 0.3 will also reach the limit in turn, as shown in FIG. 6c, at which time the total discharging current demand reaches the maximum value, and the three battery modules all output the maximum discharging current.

[0107] It can be seen that, by using the above control scheme, the control of the DC bus voltage and the power distribution can be completed among different battery modules without relying on communication to transmit the SOC information of each module. The calculation of the voltage reference value of each module only needs to obtain the sampling value of the port current of the module and the current SOC state. Moreover, the DC bus voltage is controlled by the DC / DC converter of the battery module, and in the steady state, the DC bus voltage in the discharging mode decreases with the increase of the discharging power, and the DC bus voltage in the charging mode increases with the increase of the charging power.

[0108] In the above embodiments, the plurality of battery modules with built-in DC / DC converters are connected in parallel on the same DC bus, and each adopts a voltage source type control method, has automatic response capability independent of communication, and can consider the current SOC state of each battery module in various scenarios. Through setting of the droop curve, the battery module with high SOC discharges more power in the discharging condition, and the battery module with low SOC charges more power in the charging condition. In addition, in the case of large charging and discharging power, as long as within the cell capacity range, the battery modules with different SOCs all have the ability to fully charge and discharge. The above control scheme can make the battery module with built-in DC / DC converter still exhibit voltage source characteristics, and maximize the restoration of battery characteristics. Whether the battery module is single or multiple in parallel, the DC bus voltage can be maintained stable. By using the above voltage droop control scheme, the SOC information of all battery modules does not need to be transmitted through communication, and the power distribution effect can be achieved according to the setting of the droop curve, so as to realize the SOC balance of different battery modules, and each battery module only needs to obtain its own SOC information. In the case of large charging and discharging power, each battery module can also reach the maximum charging and discharging current limit, and is not restricted by the power output of other modules.

[0109] The embodiments of the present application also provide a DC / DC converter applied to an energy storage battery module, the DC / DC converter comprising a voltage controller, a driving module and a main circuit; the voltage controller is configured to execute any of the above methods to calculate a driving signal; the driving module is configured to receive the driving signal from the voltage controller and drive the main circuit.

[0110] The embodiments of the present application also provide an energy storage battery module, the energy storage battery module comprising at least one cell and any of the above DC / DC converters.

[0111] The embodiments of the present application also provide an energy storage system, the energy storage system comprising a DC bus and a plurality of energy storage battery modules as described above.

[0112] The embodiments of the present application also provide a computer readable storage medium, the computer readable storage medium storing a computer program, the computer program being executed by a processor to implement any of the above methods.

[0113] The embodiments of the present application also provide a computer program product, the computer program product comprising a computer program, the computer program being executed by a processor to implement any of the above methods.

[0114] The computer program product can adopt a portable compact disc read-only memory (CD-ROM) and include a program code, and can run on a terminal device such as a personal computer. However, the computer program product of the present application is not limited to this, and the computer program product can adopt any combination of one or more computer readable media.

[0115] The embodiment of the present application further provides a chip used for executing any of the above methods.

[0116] The embodiment of the present application further provides a computer device including a memory and a processor, the memory stores a computer program, and the processor implements any of the above methods when executing the computer program.

[0117] Referring to FIG. 7, FIG. 7 is a structural block diagram of a computer device according to an embodiment of the present application.

[0118] The computer device is not limited in the embodiment of the present application, and for example, can be a local computer device, a cloud computer device, a distributed computer device, etc.

[0119] The computer device can include a memory 110, a processor 120 and a communication interface 130. The memory 110, the processor 120 and the communication interface 130 are connected through an internal connection path.

[0120] The memory 110 is used for storing a computer program, and in some implementation manners, the computer program can include codes for implementing the method of the embodiment of the present application.

[0121] The processor 120 is used for executing the computer program stored in the memory 110, so as to control the communication interface 130 to receive input data and information, output operation results and the like. In some implementation manners, when the scheme of the embodiment of the present application is implemented through software or firmware, the computer program for implementing the scheme of the embodiment of the present application can be saved in the processor 120 and executed by the processor 120.

[0122] The memory 110 can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. The non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM) or a flash memory. The volatile memory can be a random access memory (RAM). It should be noted that the memory 110 described herein is intended to include but not limited to these and other suitable types of any memory. As an example, the memory 110 includes a random access memory (RAM), a cache memory and a read-only memory (ROM). The memory 110 stores a computer program, and the computer program can be executed by the processor 120, so that the processor 120 implements the steps of any of the above methods.

[0123] The processor 120 can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or the processor 120 can also be any conventional processor.

[0124] In the implementation process, each step of the above method can be completed by the integrated logic circuit of hardware in the processor 120 or the instruction in the form of software. The method disclosed in combination with the embodiments of the present application can be directly embodied as hardware processor execution completion, or combined with hardware and software modules in the processor 120 to complete execution. The software module can be located in a mature storage medium in the art such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, register, etc. The storage medium is located in the memory 110, and the processor 120 reads the information in the memory 110, and combines the hardware to complete the steps of the above method. To avoid repetition, it will not be described in detail here.

[0125] In some implementations, in addition to the hardware units introduced above, the computer device can also include software modules, where the software modules can be, for example, an operating system, a basic input and output system (BIOS), application software, etc.

[0126] The operating system is used to manage hardware and / or software resources of the computer device, and is the kernel and cornerstone of the computer device. The operating system needs to handle basic transactions such as managing and configuring memory, determining the priority of system resource supply and demand, controlling input and output devices, operating network and managing file system, etc. In order to facilitate user operation, most operating systems will provide an operation interface for users to interact with the system.

[0127] The BIOS is used to run hardware initialization in the power-on boot stage, and provides runtime services for the operating system and application programs. In some implementations, the BIOS can also monitor the processor temperature and perform temperature protection strategies, etc.

[0128] Application software, also called application program, can be understood as software written for a specific application purpose of a user, and is one of the main classifications of computer software. For example, application software can be a program for realizing power control, temperature management, etc.

[0129] It can be understood that the specific examples in the present application are only to help those skilled in the art better understand the embodiments of the present application, and do not limit the protection scope of the present application.

[0130] It can be understood that in various embodiments of the present application, the size of the serial number of each process does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the present application.

[0131] It can be understood that the various embodiments described in the present application can be implemented alone or in combination, and the present application does not limit this.

[0132] Unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as understood by those skilled in the art of the present application. The terms used in the present application are only for the purpose of describing the specific embodiments and are not intended to limit the scope of the present application. The term "and / or" used in the present application includes any and all combinations of one or more related listed items. The singular forms "a", "an" and "the" used in the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0133] Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in connection with the embodiments disclosed herein can be realized in electronic hardware, or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0134] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of each embodiment described above can refer to the corresponding process in other embodiments, which will not be repeated here.

[0135] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented by other manners. For example, the above-described device embodiments are merely illustrative, for example, the division of units is merely a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0136] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place or can be distributed to a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the technical solutions of the present application.

[0137] In addition, the functional units in each embodiment of the present application can be integrated into one processing unit, or each unit can be physically present separately, or two or more units can be integrated into one unit.

[0138] If the functions are realized in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the essential part or part of the technical solutions that make contributions to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program code storage media.

[0139] The above is merely a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A parallel control method of an energy storage battery module, characterized by, A plurality of energy storage battery modules are connected in parallel to the same DC bus, and the method comprises: For at least one energy storage battery module, a target voltage reference value of the energy storage battery module is determined using a current sampled value of a target output parameter of the energy storage battery module and SOC information; the target output parameter is output current or output power; Based on the target voltage reference value of the energy storage battery module and a sampled value of the DC bus voltage, the DC bus voltage is adjusted to obtain a given value of the target output parameter; According to the given value of the target output parameter, a drive signal of a corresponding DC / DC converter of the energy storage battery module is calculated.

2. The parallel control method of the energy storage battery module according to claim 1, wherein The target voltage reference value of the energy storage battery module is determined using the current sampled value of the target output parameter and the SOC information, comprising: According to the current sampled value of the target output parameter, a target voltage reference value is determined using a corresponding relationship between the voltage reference value and the sampled value of the target output parameter; The corresponding relationship contains a target corresponding parameter, and the parameter value of the target corresponding parameter is determined according to the SOC information of the energy storage battery module.

3. The parallel control method of the energy storage battery module according to claim 2, characterized by, Taking the charging direction as the positive direction of the target output parameter, the corresponding relationship satisfies the following conditions: When the sampled value of the target output parameter is within the target output parameter value range of the energy storage battery module, the voltage reference value increases with the increase of the sampled value of the target output parameter; or, when the sampled value of the target output parameter is greater than the maximum value of the target output parameter value range, the target voltage reference value remains the maximum value of the target voltage value range of the energy storage battery module; or, when the sampled value of the target output parameter is less than the minimum value of the target output parameter value range, the target voltage reference value remains the minimum value of the target voltage value range; The target output parameter value range and the target voltage value range of the energy storage battery module are determined according to the SOC information of the energy storage battery module.

4. The parallel control method of the energy storage battery module according to claim 3, characterized by, The target output parameter is output current, the target corresponding parameter includes discharge slope and charge slope, and the corresponding relationship is represented as follows when a sample value of the target output parameter is located in a numerical range of the target output parameter: Wherein, Vref represents the voltage reference value, Vn represents the no-load voltage, Io represents the sampled value of the output current, k_dis(SOC) represents the discharge slope, k_char(SOC) represents the charge slope, I_dis_max represents the maximum discharge current, and I_char_max represents the maximum charge current.

5. The method of claim 4, wherein, The discharge slope decreases with the increase of the SOC value, and / or the charge slope increases with the increase of the SOC value.

6. The parallel control method of the energy storage battery module according to claim 3, wherein The DC bus voltage is adjusted based on the target voltage reference value of the energy storage battery module and the sampled value of the DC bus voltage to obtain the given value of the target output parameter, comprising: In the case where the target voltage reference value does not match the sampled value of the DC bus voltage: When the sampling value of the DC bus voltage is within the target voltage numerical range, a given value of the target output parameter is determined according to the sampling value of the DC bus voltage and the corresponding relationship; or when the sampling value of the DC bus voltage is greater than the maximum value of the target voltage numerical range, the given value of the target output parameter is determined as the maximum value of the target output parameter numerical range; or when the sampling value of the DC bus voltage is less than the minimum value of the target voltage numerical range, the given value of the target output parameter is determined as the minimum value of the target output parameter numerical range.

7. A DC / DC converter, characterized by The DC / DC converter is applied to an energy storage battery module, and the DC / DC converter comprises a voltage controller, a driving module and a main circuit. The voltage controller is configured to execute the method in any one of claims 1 to 6 to calculate a driving signal. The driving module is configured to receive the driving signal from the voltage controller and drive the main circuit.

8. An energy storage battery module, characterized by, The energy storage battery module comprises at least one battery cell and the DC / DC converter in claim 7.

9. An energy storage system characterized by, The energy storage system comprises a DC bus and a plurality of energy storage battery modules in claim 8.

10. A computer device, comprising: The computer device comprises a memory and a processor, the memory stores a computer program, and the processor executes the computer program to implement the method in any one of claims 1 to 6.

11. A chip, characterized by The chip is configured to execute the method in any one of claims 1 to 6.

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