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

Abstract

The invention provides an energy storage battery module and a parallel control method thereof, a DC / DC converter and related equipment, a plurality of energy storage battery modules are connected in parallel on the same DC bus, and the method comprises the following steps: aiming at at least one energy storage battery module, using a current sampling value and SOC information of a target output parameter of the energy storage battery module to determine the current sampling value of the target output parameter of the energy storage battery module; determining a target voltage reference value of the energy storage battery module; the target output parameter is output current or output power; based on the target voltage reference value of the energy storage battery module and the sampling value of the direct current bus voltage, adjusting the direct current bus voltage to obtain a given value of the target output parameter; and calculating a driving signal of a DC / DC converter corresponding to the energy storage battery module according to a given value of the target output parameter. According to the invention, the energy storage battery modules show voltage source characteristics when being connected in parallel, and the effect of power distribution can be achieved without transmitting SOC information by means of communication.

Description

Technical Field

[0001] This application relates to the field of energy storage battery technology, and in particular to energy storage battery modules and their parallel control methods, DC / DC converters and related equipment. Background Technology

[0002] In recent years, the installed capacity of energy storage systems has been increasing year by year. As the total capacity of the entire energy storage system increases, the required system capacity of the battery modules also increases, often resulting in an architecture where multiple energy storage battery modules are connected in parallel to the DC bus. However, with each energy storage battery module connected in parallel to the same DC bus, their State of Charge (SOC) varies, making it a significant challenge to consider changes in SOC when allocating charging and discharging power.

[0003] Currently, one approach to power distribution in parallel systems is to set up a master unit and several slave units. The master unit uses voltage loop control and outputs current commands, while the slave units use current loop control and share the current commands according to the state of charge (SOC). However, this method requires high-speed communication between the master and slave units to meet the demand for rapid power response. Furthermore, energy storage battery modules using current loop control exhibit current source characteristics rather than voltage source characteristics, making it difficult to accurately reflect the battery's operating characteristics.

[0004] Based on this, this application provides an energy storage battery module and its parallel control method, a DC / DC converter and related equipment to improve related technologies. Summary of the Invention

[0005] The purpose of this application is to provide an energy storage battery module and its parallel control method, DC / DC converter and related equipment, which do not rely on communication to transmit the SOC information of the energy storage battery module, so that the energy storage battery module exhibits voltage source characteristics when connected in parallel.

[0006] The objective of this application is achieved through the following technical solution:

[0007] In a first aspect, this application provides a parallel control method for energy storage battery modules, wherein multiple energy storage battery modules are connected in parallel on the same DC bus, the method comprising:

[0008] For at least one energy storage battery module, a target voltage reference value for the energy storage battery module is determined using the current sampled value of the target output parameter and the SOC information; the target output parameter is the output current or the output power.

[0009] Based on the target voltage reference value of the energy storage battery module and the sampled value of the DC bus voltage, the DC bus voltage is adjusted to obtain the given value of the target output parameter;

[0010] Based on the given value of the target output parameter, calculate the drive signal of the corresponding DC / DC converter of the energy storage battery module.

[0011] In some embodiments, determining the target voltage reference value of the energy storage battery module using the current sampled value of the target output parameter and the SOC information includes:

[0012] Based on the current sampled value of the target output parameter, the target voltage reference value is determined using the correspondence between the voltage reference value and the sampled value of the target output parameter;

[0013] The correspondence relationship includes target correspondence parameters, and the parameter values ​​of the target correspondence parameters are determined based on the SOC information of the energy storage battery module.

[0014] In some embodiments, the charging direction is taken as the positive direction of the target output parameter, and the correspondence satisfies the following conditions:

[0015] 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 as the sampled value of the target output parameter increases; 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 at 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 at the minimum value of the target voltage value range.

[0016] The target output parameter range and target voltage range of the energy storage battery module are determined based on the SOC information of the energy storage battery module.

[0017] In some embodiments, the target output parameter is the output current, and the target corresponding parameter includes the discharge slope and the charging slope. When the sampled value of the target output parameter is within the range of the target output parameter value, the correspondence is expressed as follows:

[0018]

[0019] 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 charging slope, I_dis_max represents the maximum discharge current, and I_char_max represents the maximum charging current.

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

[0021] In some embodiments, 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 a given value for the target output parameter includes:

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

[0023] When the sampled value of the DC bus voltage is within the target voltage range, the given value of the target output parameter is determined based on 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 range, the given value of the target output parameter is determined to be the maximum value of the target output parameter range; or, when the sampled value of the DC bus voltage is less than the minimum value of the target voltage range, the given value of the target output parameter is determined to be the minimum value of the target output parameter range.

[0024] Secondly, this application provides a DC / DC converter for use in an energy storage battery module, the DC / DC converter including a voltage controller, a drive module and a main circuit;

[0025] The voltage controller is used to execute any of the above methods to calculate the drive signal;

[0026] The drive module is used to receive drive signals from the voltage controller and drive the main circuit.

[0027] Thirdly, this application provides an energy storage battery module, which includes at least one battery cell and any of the aforementioned DC / DC converters.

[0028] Fourthly, this application provides an energy storage system, which includes a DC bus and a plurality of energy storage battery modules as described above.

[0029] Fifthly, this application provides a computer device, the computer device including a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement any of the methods described above.

[0030] Sixthly, this application provides a chip for performing any of the above methods.

[0031] This application provides an energy storage battery module and its parallel control method, a DC / DC converter, and related equipment. For energy storage battery modules connected in parallel on the same DC bus, a target voltage reference value is determined using sampled values ​​of target output parameters (e.g., output current or output power) and SOC information. Based on the target voltage reference value and the sampled value of the DC bus voltage, the DC bus voltage is adjusted to obtain a given value for the target output parameter. According to the given value of the target output parameter, the drive signal for the corresponding DC / DC converter of the energy storage battery module is calculated, thereby realizing the parallel control of the energy storage battery module. The above embodiments enable the energy storage battery modules to exhibit voltage source characteristics when connected in parallel, accurately reflecting the actual operating characteristics of the battery. Furthermore, power distribution can be achieved without relying on communication to transmit the SOC information of the energy storage battery modules. Attached Figure Description

[0032] This application will be further described below with reference to the accompanying drawings and specific embodiments.

[0033] Figure 1 This is a schematic diagram of a parallel energy storage system provided in an embodiment of this application.

[0034] Figure 2 This is a flowchart illustrating a parallel control method for an energy storage battery module provided in an embodiment of this application.

[0035] Figure 3 This is a schematic diagram of the overall control loop of a DC / DC converter provided in an embodiment of this application.

[0036] Figure 4 This is a schematic diagram illustrating the correspondence between a voltage reference value and a sampled value of a target output parameter, provided in an embodiment of this application.

[0037] Figure 5 This is a schematic diagram of a drooping curve provided in an embodiment of this application.

[0038] Figure 6a This is a schematic diagram of current distribution of battery modules with different SOCs under discharge conditions provided in an embodiment of this application (none of the three battery modules have reached the maximum discharge current).

[0039] Figure 6b This is a schematic diagram of current distribution of battery modules with different SOCs under discharge conditions provided in an embodiment of this application (one battery module reaches the maximum discharge current).

[0040] Figure 6c This is a schematic diagram of current distribution for battery modules with different SOCs under discharge conditions provided in an embodiment of this application (all three battery modules reach their maximum discharge current).

[0041] Figure 7 This is a structural block diagram of a computer device provided in an embodiment of this application. Detailed Implementation

[0042] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] In the description of the embodiments of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0044] See Figure 1 , Figure 1 This is a schematic diagram of a parallel energy storage system provided in an embodiment of this application.

[0045] In recent years, the installed capacity of energy storage systems has been increasing year by year. As the total capacity of the entire energy storage system increases, the required system capacity of the battery modules also increases. This often leads to an architecture where multiple energy storage battery modules are connected in parallel to the DC bus. A parallel energy storage system, such as... Figure 1 As shown in the figure, the battery module is an energy storage battery module. However, since each energy storage battery module is connected in parallel to the same DC bus, and the state of charge (SOC) of each battery is different, how to consider the changes in SOC to allocate charging and discharging power has become a major challenge.

[0046] Currently, one approach to power distribution in parallel systems is to set up a master unit and several slave units. The master unit uses voltage loop control and outputs current commands, while the slave units use current loop control and share the current commands according to the state of charge (SOC). However, this method requires high-speed communication between the master and slave units to meet the demand for rapid power response. Furthermore, energy storage battery modules using current loop control exhibit current source characteristics rather than voltage source characteristics, making it difficult to accurately reflect the battery's operating characteristics.

[0047] See Figure 2 and Figure 3 , Figure 2 This is a flowchart illustrating a parallel control method for an energy storage battery module provided in an embodiment of this application. Figure 3This is a schematic diagram of the overall control loop of a DC / DC converter provided in an embodiment of this application.

[0048] To improve the relevant technology, this application provides a parallel control method for energy storage battery modules, wherein multiple energy storage battery modules are connected in parallel on the same DC bus, and the method includes steps S101 to S103.

[0049] Step S101: For at least one energy storage battery module, determine the target voltage reference value of the energy storage battery module using the current sampled value of the target output parameter and the SOC information; the target output parameter is the output current or the output power.

[0050] Step S102: Based on the target voltage reference value of the energy storage battery module and the sampled value of the DC bus voltage, adjust the DC bus voltage to obtain the given value of the target output parameter.

[0051] Step S103: Calculate the drive signal of the corresponding DC / DC converter of the energy storage battery module according to the given value of the target output parameter.

[0052] In the above embodiments, the energy storage battery module includes, for example, one or more battery cells. In some embodiments, the energy storage battery module may have a built-in DC / DC converter. That is, the corresponding DC / DC converter of the energy storage battery module may be built into the energy storage battery module, or it may be set separately and have communication functions with the energy storage battery module; the above embodiments do not limit this. Energy storage battery modules with built-in DC / DC converters can realize the independent operation of different energy storage battery modules, improve the problems of series mismatch or parallel adaptation, reduce the mutual influence between energy storage battery modules, and are highly competitive in practical applications.

[0053] In some embodiments, SOC information (e.g., SOC value) can be represented by a numerical value between 0 and 1, or by a percentage. The target voltage reference value can change in each control cycle until the voltage regulation reaches a steady state. The DC bus voltage is regulated, for example, by closed-loop regulation of the DC bus voltage. When the closed-loop regulation (also known as closed-loop control) reaches a steady state, the target voltage reference value and the sampled value of the DC bus voltage match. Matching the target voltage reference value and the sampled value of the DC bus voltage means, for example, that the target voltage reference value and the sampled value of the DC bus voltage are completely identical, or 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, or 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. The target difference and target ratio can be selected according to actual needs, and the above embodiments do not limit this.

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

[0055] The existing methods rely on high-speed communication between the master and slave devices. Furthermore, many of these methods employ current loop control, which struggles to accurately reproduce the battery operating characteristics of the energy storage modules. The above embodiment enables multiple energy storage modules connected in parallel to automatically adjust their power output based on SOC information without relying on high-speed communication between the master and slave devices, thus improving the overall efficiency and stability of the energy storage system. Moreover, by employing voltage loop control for the energy storage modules, the battery operating characteristics are accurately reproduced. Specifically, the target voltage reference value for each energy storage module is first determined based on the current sampled values ​​of its target output parameters and its SOC information. Then, the DC bus voltage is regulated through a voltage adjustment mechanism. Without relying on communication between different energy storage modules, each module can autonomously adjust its output power based on its own SOC information. This allows modules with higher SOC to output more power during discharge and modules with lower SOC to charge more during charging, ensuring overall voltage stability and power balance in the energy storage system.

[0056] The above method enables energy storage battery modules to exhibit voltage source characteristics when connected in parallel, accurately replicating the actual operating characteristics of the batteries and improving the response speed and stability of the energy storage system. Whether single or multiple energy storage battery modules are connected in parallel, the DC bus voltage remains stable. Furthermore, power distribution can be achieved without relying on communication to transmit the SOC information of the energy storage battery modules, thus realizing SOC balancing among different energy storage battery modules. Each energy storage battery module only needs to obtain its own SOC information, greatly improving the accuracy and real-time performance of power distribution.

[0057] In some embodiments, determining the target voltage reference value of the energy storage battery module using the current sampled value of the target output parameter and the SOC information of the energy storage battery module may include: determining the target voltage reference value based on the current sampled value of the target output parameter and the correspondence between the voltage reference value and the sampled value of the target output parameter; wherein the correspondence includes a target corresponding parameter, and the parameter value of the target corresponding parameter is determined based on the SOC information of the energy storage battery module.

[0058] In the above embodiments, the correspondence refers to the mathematical or empirical relationship between the sampled value of the target output parameter and the voltage reference value, reflecting the voltage requirement that the energy storage battery module should achieve at a specific SOC level to realize the predetermined output. The correspondence can be represented by a correspondence formula or a correspondence model. The target correspondence parameter refers to the parameter included in the correspondence, such as the formula parameter in the correspondence formula or the model parameter in the correspondence model. The correspondence formula can be, for example, a linear formula (e.g., a drooping curve) or a nonlinear formula. The above embodiments do not limit the correspondence model, which can be, for example, a deep learning-based model.

[0059] The above embodiments analyze the current sampled values ​​of the target output parameters of the energy storage battery modules and the SOC information, and use a dynamic adjustment method to determine the target voltage reference value of the battery modules participating in voltage regulation. Specifically, based on the current sampled values ​​of the target output parameters, the target voltage reference value is dynamically adjusted using a pre-established correspondence between the voltage reference value and the target output parameters. This correspondence is set according to the SOC information of the energy storage battery modules, enabling the energy storage battery modules to automatically match a suitable target voltage reference value at different SOC levels. By calculating and dynamically adjusting the target voltage reference value in real time, the response speed and control accuracy of the energy storage battery modules when operating in parallel are improved, thereby optimizing the charging and discharging efficiency of the system. By using a method that combines SOC information with target output parameters, the battery modules can automatically adjust their output according to the current state, reducing the imbalance caused by SOC differences, achieving SOC balance among different energy storage battery modules, and improving the safety and stability of the system.

[0060] In a specific application scenario, taking 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 characteristics: when the sampled value of the DC bus voltage is within the target voltage range of the energy storage battery module, the sampled value of the DC bus voltage increases as the sampled value of the target output parameter increases; or, when the sampled value of the DC bus voltage is greater than the maximum value of the target voltage range, the sampled value of the target output parameter remains at the maximum value under charging conditions (i.e., the maximum value of the target output parameter range); or, when the sampled value of the DC bus voltage is less than the minimum value of the target voltage range, the sampled value of the target output parameter remains at the maximum value under discharging conditions (i.e., the minimum value of the target output parameter range); wherein, the target voltage range and the target output parameter range of the energy storage battery module are determined based on the SOC information of the energy storage battery module.

[0061] It's important to note that the target voltage reference value and the sampled DC bus voltage do not have the same physical meaning. The following example uses output current as the target output parameter for illustration. For one battery module (in this article, one battery module is equivalent to one battery module), the sampled DC bus voltage can only match the target voltage reference value (achieving closed-loop control) when the output current is within the upper and lower limits of the charge / discharge current (i.e., between the maximum discharge current and the maximum charge current). When the output current of this battery module reaches the maximum discharge current, the sampled DC bus voltage will be controlled by other modules that have not reached their maximum discharge current, and in this case, the sampled DC bus voltage can be lower than the target voltage reference value of this battery module. When the output current of this battery module reaches the maximum charge current, the sampled DC bus voltage will be controlled by other modules that have not reached their maximum charge current, and in this case, the sampled DC bus voltage can be higher than the target voltage reference value of this battery module. This means that the battery module has reached its voltage regulation limit (and will no longer participate in subsequent voltage regulation). The battery module will maintain its maximum charging current or maximum discharging current, and the remaining battery modules that have not reached their regulation limit will be responsible for the stable control of the DC bus voltage.

[0062] In other words, the above embodiments can perform voltage regulation on multiple energy storage battery modules connected in parallel to the same DC bus. Furthermore, in practical applications, closed-loop regulation can be performed on all energy storage battery modules, or only on a portion of them (in this case, the energy storage battery modules not participating in closed-loop regulation will remain at their upper limit of voltage regulation capability, and their target output parameters will remain at the maximum or minimum value of the corresponding target output parameter range). However, since all energy storage battery modules are connected in parallel to the same DC bus, the sampled values ​​of the corresponding DC bus voltages for these energy storage battery modules are the same.

[0063] See Figure 4 , Figure 4 This is a schematic diagram illustrating the correspondence between a voltage reference value and a sampled value of a target output parameter, provided in an embodiment of this application.

[0064] like Figure 4 As shown, in some embodiments, the charging direction is taken as the positive direction of the target output parameter, and the correspondence can satisfy 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 as the sampled value of the target output parameter increases; 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 at 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 at 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] Theoretically, the sampled values ​​of the target output parameters should not exceed their numerical range. For example, the output current of a single battery module will not exceed its charging and discharging current limit. However, considering factors such as sampling errors, even when the sampled values ​​of the target output parameters exceed their numerical range, the target voltage reference value can still be calculated to obtain a definite result, which can then be used to perform subsequent voltage regulation.

[0066] In the above embodiments, the charging direction refers to the direction of current flow during the charging process of the energy storage battery module, which can be defined as the positive direction. Alternatively, in some other embodiments, the discharging direction can be used as the positive direction, which is not limited in this application. Using the charging direction as the positive direction of the target output parameter means that the positive direction of the output current or output power is consistent with the charging direction. The target voltage value range is a voltage threshold range defined based on the SOC information of the energy storage battery module, and has corresponding maximum and minimum values. The target output parameter value range is an output parameter threshold range defined based on the SOC information of the energy storage battery module, and has corresponding maximum and minimum values. When the target output parameter is the output current, the target output parameter value range is the target output current output range, with its maximum value being the maximum charging current and its minimum value being 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, with its maximum value being the maximum charging power and its minimum value being 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 correspondence between the voltage reference value and the sampled value of the target output parameter. By establishing the dynamic correspondence 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 practical applications, the positive direction of the port current (i.e., output current) of each battery module (i.e., 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 and the port current i1 of the first battery module have a linear relationship, such as a drooping curve. When the port voltage v1 is within the corresponding target voltage range of the battery module (a function of SOC), the port voltage v1 and the port current i1 have a monotonically increasing relationship, that is, the port voltage v1 increases as the port current i1 increases; when the port voltage v1 is greater than the maximum value of the target voltage range, the port current i1 remains at the maximum charging current; when the port voltage v1 is less than the minimum value of the target voltage range, the port current i1 remains at the maximum discharging current.

[0070] The port voltage of the second battery module is controlled so that the port voltage v2 and the port current i2 of the second battery module have a linear relationship, such as a drooping curve. When the port voltage v2 is within the corresponding target voltage 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 as the port current i2 increases; when the port voltage v2 is greater than the maximum value of the target voltage range, the port current i2 remains at the maximum charging current; when the port voltage v2 is less than the minimum value of the target voltage range, the port current i2 remains at the maximum discharging current.

[0071] ...

[0072] The port voltage of the nth battery module is controlled such that the port voltage vn and the port current in of the nth battery module have a linear relationship, for example, a drooping curve. When the port voltage vn is within the corresponding target voltage 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 as the port current in increases; when the port voltage vn is greater than the maximum value of the target voltage range, the port current in remains at the maximum charging current; when the port voltage vn is less than the minimum value of the target voltage range, the port current in remains at the maximum discharging current.

[0073] The above embodiments distribute power among parallel modules based on their State of Charge (SOC), ensuring equal port voltages and that output current is allocated according to SOC values. Modulation of v1 and i1, v2 and i2…vn and in ensures that when v1 = v2 =…vn, the relationship between i1, i2,…in satisfies the requirement for balanced SOC among different battery modules. Specifically, during charging, the absolute values ​​of i1, i2,…in are inversely proportional to the SOC value; during discharging, the absolute values ​​of i1, i2,…in are directly proportional to the SOC value.

[0074] In some embodiments, the target output parameter may be the output current, and the target corresponding parameter may include the discharge slope k_dis(SOC) and the charging slope k_char(SOC). When the sampled value of the target output parameter is within the range of the target output parameter value, the correspondence can be expressed as follows.

[0075]

[0076] 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 charging slope, I_dis_max represents the maximum discharge current, and I_char_max represents the maximum charging current.

[0077] In the above embodiments, the target output parameter is the output current, the maximum value of the corresponding target output parameter value range is the maximum charging current, and the minimum value of the corresponding target output parameter value range is the maximum discharging current.

[0078] The discharge slope k_dis(SOC) refers to the slope of the straight line formed by the voltage reference value (vertical axis) and the sampled output current value (horizontal axis) during the discharge process at a specific SOC. The charging slope k_char(SOC) refers to the slope of the straight line formed by the voltage reference value (vertical axis) and the sampled output current value (horizontal axis) during the charging process at a specific SOC. The no-load voltage Vn refers to the voltage value of the energy storage battery module when there is no load (i.e., the output current is zero). The sampled output current value Io is the real-time monitored output current value of the energy storage battery module, used to calculate and control the voltage reference value. The maximum discharge current is the maximum allowable current value of the energy storage battery module during the discharge process. The maximum charging current is the maximum allowable current value of the energy storage battery module during the charging process.

[0079] In practical applications, the target voltage range and target output parameter range of different energy storage battery modules can be the same or different, and the above embodiments do not limit this.

[0080] In some embodiments, the discharge slope k_dis(SOC) may decrease as the SOC value increases. In some embodiments, the charging slope k_char(SOC) may increase as the SOC value increases.

[0081] In some embodiments, the discharge slope k_dis(SOC) can be calculated in the following manner.

[0082]

[0083] In some embodiments, the charging slope k_char(SOC) can be calculated in the following manner.

[0084]

[0085] Wherein, SOCmin represents the minimum value of SOC, SOCmax represents the maximum value of 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(SOC max) 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.

[0086] In some embodiments, k_dis(SOCmin) = (Vn - Vmin) / I_dis_max, k_dis(SOCmax) = β × k_dis(SOCmin). In some embodiments, k_char(SOCmax) = (Vmax - Vn) / I_char_max, k_char(SOCmin) = β × k_char(SOCmax). Wherein, Vmin represents the minimum voltage under discharge conditions, Vmax is the maximum voltage under defined charging conditions, and β represents the slope fluctuation coefficient.

[0087] The slope fluctuation coefficient β characterizes the degree of fluctuation between the maximum and minimum slope values. The above embodiments do not limit the slope fluctuation coefficient β, which can be, for example, 0.05, 0.1, 0.15, etc. In other embodiments, different slope fluctuation coefficients can be set for the discharge slope and the charging slope; this application does not impose any limitations on this.

[0088] 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.

[0089] For example, each battery module's built-in DC / DC converter uses... Figure 3 The control scheme shown calculates the voltage reference value for each control cycle based on the current SOC and the sampled output current value. The voltage controller's inputs are the calculated voltage reference value and the sampled DC bus voltage value. The DC bus voltage is regulated by the voltage controller, and the output current setpoint is used to calculate the drive signal for the DC / DC converter. The above scheme calculates the voltage reference value by substituting the sampled output current value into the droop curve. An alternative scheme calculates the voltage reference value by substituting the port power (i.e., output power) into the droop curve (i.e., using output power instead of output current). The design of the horizontal axis of the droop curve differs, but the schemes are similar. The following explanation only uses the output current sampling scheme to illustrate the method for developing the droop curve for calculating the voltage reference value.

[0090] See Figure 5 , Figure 5 This is a schematic diagram of a drooping curve provided in an embodiment of this application.

[0091] A schematic diagram of the droop curve for calculating the voltage reference value is shown below. Figure 5 As shown in the diagram. Here, Io represents the sampled value of the battery module's port current (i.e., output current). We can define the discharge current as negative and the charging current as positive (i.e., the charging direction as positive). I_dis_max represents the maximum discharge 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 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 range), corresponding to the discharging condition. For example, the steps for defining the droop curve and calculating the voltage reference value can be as follows.

[0092] S1: Determine the boundaries of the droop curve according to the design requirements of the DC / DC converter, namely 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.

[0093] S2: Determine the slopes k_dis(SOC) and k_char(SOC) of the droop curves under charging and discharging conditions based on the parameters in S1. The slopes of the droop curves (including the discharging and charging slopes) are functions of SOC. Under discharging conditions, the slope of the droop curve decreases monotonically with respect to SOC; that is, the higher the SOC value, the smaller the slope. Under charging conditions, the slope of the droop curve increases monotonically with respect to SOC; that is, the higher the SOC value, the larger the slope. The maximum and minimum slope values ​​can be determined based on the upper and lower limits of the voltage reference value and the upper and lower limits of the charging and discharging current.

[0094] It should be noted that the schematic diagram of the drooping curve in this application (i.e., Figure 5 This is based on the specification of the positive direction of the charging and discharging current. If the specification of the positive direction of the charging and discharging current is opposite to that of this application, then... Figure 5 A mirror flip is sufficient; this can be considered the same or similar solution as that in this application. Determining the slope of the droop curve, as long as it conforms to the above basic principles, can achieve a balance in the SOC of different battery modules. A specific calculation method is given here as an example; specific details can be flexibly adjusted according to the actual solution requirements.

[0095] Under discharge conditions, let k_dis(SOC) be the maximum value of k_dis(SOC) corresponding to the minimum SOC value SOCmin. k_dis(SOCmin) can be taken as (Vn-Vmin) / I_dis_max, where Vn is the no-load voltage, corresponding to the voltage reference value when the charging / discharging current is 0. Let k_dis(SOC) be the minimum value of k_dis(SOC) corresponding to the maximum SOC value SOCmax. k_dis(SOCmax) can be taken as β×k_dis(SOCmin), where β is the slope fluctuation coefficient, which can be taken as β=0.1. Then, the calculation of k_dis(SOC) can be set as follows:

[0096]

[0097] Under charging conditions, let k_char(SOC) be the maximum value of k_char(SOC) when SOC reaches its maximum value (SOCmax), which can be taken as (Vmax-Vn) / I_char_max. Let k_char(SOC) be the minimum value of k_char(SOC) when SOC reaches its minimum value (SOCmin), which can be taken as β×k_char(SOCmin). Then, the calculation of k_char(SOC) can be set as follows:

[0098]

[0099] The voltage reference value boundaries for different SOCs are determined based on 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. Therefore, the formula for calculating the voltage reference value Vref based on the droop curve is:

[0100]

[0101] By substituting the sampled value of Io into the above formula, the corresponding target voltage reference value can be calculated.

[0102] In some embodiments, 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 may include: when the target voltage reference value and the sampled value of the DC bus voltage do not match: when the sampled value of the DC bus voltage is within the target voltage range, determining the given value of the target output parameter according to the sampled value of the DC bus voltage and the correspondence; or, when the sampled value of the DC bus voltage is greater than the maximum value of the target voltage range, determining the given value of the target output parameter to be the maximum value of the target output parameter range; or, when the sampled value of the DC bus voltage is less than the minimum value of the target voltage range, determining the given value of the target output parameter to be the minimum value of the target output parameter range.

[0103] When the target output parameter is output current, the maximum value of the target output parameter range is the maximum value under charging conditions, i.e., the maximum charging current; the minimum value of the target output parameter range is the maximum value under discharging conditions, i.e., the maximum discharging current. When the target output parameter is output power, the maximum value of the target output parameter range is the maximum value under charging conditions, i.e., the maximum charging power; the minimum value of the target output parameter range is the maximum value under discharging conditions, i.e., the maximum discharging power. The maximum charging power and maximum discharging power can be selected according to actual needs, such as setting them according to the design requirements of the relevant equipment.

[0104] Using the above voltage droop control scheme, battery modules with different SOC values ​​exhibit the following external characteristics. The DC bus voltage is jointly controlled by all parallel battery modules, and each battery module exhibits voltage source characteristics. The slope of the droop curve allows battery modules that have not reached their charge / discharge current limits to allocate the total charge / discharge power demand on the DC bus according to their SOC. This application only uses the discharge condition as an example to illustrate the current distribution of battery modules with different SOCs. The charging condition is similar to the discharge condition and will not be described in detail here.

[0105] See Figures 6a to 6c , Figure 6a This is a schematic diagram of current distribution for battery modules with different states of charge (SOC) under discharge conditions provided in an embodiment of this application (none of the three battery modules have reached their maximum discharge current). Figure 6b This is a schematic diagram of current distribution for battery modules with different states of charge (SOC) under discharge conditions provided in an embodiment of this application (one battery module reaches its maximum discharge current). Figure 6c This is a schematic diagram of current distribution for battery modules with different SOCs under discharge conditions provided in an embodiment of this application (all three battery modules reach their maximum discharge current).

[0106] like Figures 6a to 6c As shown, when the total discharge current on the DC bus gradually increases from zero, the DC bus voltage gradually decreases from the no-load voltage Vn. The DC bus voltage is always controlled and stabilized by the battery modules that have not reached the current limit (maximum discharge current under discharge conditions). Figure 6a As shown, if none of the three battery modules reach the discharge current limit (i.e., the maximum discharge current), all three battery modules participate in closed-loop control. In steady state, the voltage reference value of each battery module matches the sampled value of the DC bus voltage. The discharge current value of each module (i.e., the given value of the output current) is the current value corresponding to the intersection of the DC bus voltage value and the droop curve. It can be seen that the module with a larger SOC has a smaller discharge slope on the droop curve, and its corresponding discharge current value is also larger, i.e., I1>I2>I3. Figure 6b As shown, if the total discharge current demand increases further, the DC bus voltage will decrease further. At this point, the battery module with SOC = 1.0 will reach its discharge current limit first, and its discharge current will no longer increase. The voltage regulator will reach saturation and will no longer participate in closed-loop control. However, the discharge current of the two battery modules with SOC = 0.8 and SOC = 0.3 can continue to increase, and these two battery modules will still participate in closed-loop control. If the total discharge current demand increases further, the battery modules with SOC = 0.8 and SOC = 0.3 will also reach their limits successively. Figure 6c As shown, the total discharge current demand reaches its maximum value at this time, and all three battery modules output at their maximum discharge current.

[0107] As can be seen, using the above control scheme, different battery modules can control the DC bus voltage and distribute power without relying on communication to transmit their respective SOC information. The calculation of the voltage reference value for each module only requires obtaining the sampled value of the port current of that module and the current SOC state. Furthermore, the DC bus voltage is controlled by the DC / DC converter of the battery module. In steady state, the DC bus voltage decreases as the discharge power increases during discharge, while it increases as the charging power increases during charging.

[0108] In the above embodiments, multiple battery modules with built-in DC / DC converters are connected in parallel on the same DC bus. All modules employ a voltage source control method, possessing automatic response capabilities independent of communication, and can consider the current SOC state of each battery module in various scenarios. By setting the droop curve, battery modules with high SOC output more power during discharge and battery modules with low SOC charge more during charging. Furthermore, in applications with high charge / discharge power, as long as it is within the cell's capacity, battery modules with different SOCs can all have the capability for full-power charge / discharge. This control scheme ensures that the battery modules with built-in DC / DC converters still exhibit voltage source characteristics, maximizing the restoration of battery characteristics. Whether the battery modules are single or multiple connected in parallel, the DC bus voltage remains stable. This voltage droop control scheme eliminates the need for communication to transmit the SOC information of all battery modules; it achieves power distribution based on the droop curve setting, thereby achieving SOC balance among different battery modules. Each battery module only needs to obtain its own SOC information. In applications with high charging and discharging power, each battery module can reach its maximum charging and discharging current limit without being constrained by the output of other modules.

[0109] This application also provides a DC / DC converter for use in an energy storage battery module. The DC / DC converter includes a voltage controller, a drive module, and a main circuit. The voltage controller is used to execute any of the above methods to calculate a drive signal. The drive module is used to receive the drive signal from the voltage controller and drive the main circuit.

[0110] This application also provides an energy storage battery module, which includes at least one battery cell and any of the aforementioned DC / DC converters.

[0111] This application also provides an energy storage system, which includes a DC bus and a plurality of energy storage battery modules as described above.

[0112] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements any of the above methods.

[0113] This application also provides a computer program product, which includes a computer program that, when executed by a processor, implements any of the methods described above.

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

[0115] This application also provides a chip for performing any of the above methods.

[0116] This application also provides a computer device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement any of the methods described above.

[0117] See Figure 7 , Figure 7 This is a structural block diagram of a computer device provided in an embodiment of this application.

[0118] The embodiments of this application do not limit the computer device, which may be, for example, a local computer device, a cloud computer device, a distributed computer device, etc.

[0119] The computer device may 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 internal connection paths.

[0120] The memory 110 is used to store computer programs, which in some implementations may include code for implementing the methods of the embodiments of this application.

[0121] The processor 120 executes the computer program stored in the memory 110 to control the communication interface 130 to receive input data and information, and output operation results and other data. In some implementations, when the solutions of the embodiments of this application are implemented by software or firmware, the computer program used to implement the solutions of the embodiments of this application can be stored in the processor 120 and executed by the processor 120.

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

[0123] The processor 120 can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor, or the processor 120 can be any conventional processor.

[0124] In implementation, each step of the above method can be completed by the integrated logic circuitry of the hardware in the processor 120 or by instructions in software form. The method disclosed in the embodiments of this application can be directly implemented by the hardware processor, or by a combination of hardware and software modules in the processor 120. The software modules can be located in mature storage media in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in the memory 110, and the processor 120 reads the information in the memory 110 and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are not provided here.

[0125] In some implementations, in addition to the hardware units described above, computer devices may also include software modules, such as operating systems, basic input / output systems (BIOS), and application software.

[0126] An operating system is used to manage the hardware and / or software resources of a computer device; it is the kernel and foundation of the computer. The operating system handles fundamental tasks such as managing and configuring memory, determining the priority of system resource allocation, controlling input and output devices, operating the network, and managing the file system. To facilitate user operation, most operating systems provide a user interface for interaction with the system.

[0127] The BIOS is used to perform hardware initialization during the power-on boot phase and to provide runtime services for the operating system and applications. In some implementations, the BIOS can also monitor and display processor temperature and execute temperature protection strategies.

[0128] Application software, also known as an application program, can be understood as software written for a specific user application purpose, and is one of the main categories of computer software. For example, application software can be a program used to achieve purposes such as power control and temperature management.

[0129] It is understood that the specific examples in this application are only intended to help those skilled in the art better understand the implementation of this application, and are not intended to limit the scope of protection of this application.

[0130] It is understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of this application.

[0131] It is understood that the various implementation methods described in this application can be implemented individually or in combination, and this application does not limit them.

[0132] Unless otherwise stated, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items. The singular forms "a," "the," and "the" as used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0133] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented 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 this application.

[0134] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the embodiments described above can be referred to the corresponding processes in other embodiments, and will not be repeated here.

[0135] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0136] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the technical solution in this application, depending on actual needs.

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

[0138] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0139] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A parallel control method for an energy storage battery module, characterized in that, The method includes connecting multiple energy storage battery modules in parallel on the same DC bus. For at least one energy storage battery module, a target voltage reference value for the energy storage battery module is determined using the current sampled value of the target output parameter and the SOC information; the target output parameter is the output current or the output power. Based on the target voltage reference value of the energy storage battery module and the sampled value of the DC bus voltage, the DC bus voltage is adjusted to obtain the given value of the target output parameter; Based on the given value of the target output parameter, calculate the drive signal of the corresponding DC / DC converter of the energy storage battery module.

2. The parallel control method for energy storage battery modules according to claim 1, characterized in that, The step of determining the target voltage reference value of the energy storage battery module using the current sampled value of the target output parameter and the SOC information includes: Based on the current sampled value of the target output parameter, the target voltage reference value is determined using the correspondence between the voltage reference value and the sampled value of the target output parameter; The correspondence relationship includes target correspondence parameters, and the parameter values ​​of the target correspondence parameters are determined based on the SOC information of the energy storage battery module.

3. The parallel control method for energy storage battery modules according to claim 2, characterized in that, Taking the charging direction as the positive direction of the target output parameter, the correspondence satisfies the following condition: 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 as the sampled value of the target output parameter increases; 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 at 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 at the minimum value of the target voltage value range. The target output parameter range and target voltage range of the energy storage battery module are determined based on the SOC information of the energy storage battery module.

4. The parallel control method for energy storage battery modules according to claim 3, characterized in that, The target output parameter is the output current, and the corresponding target parameters include the discharge slope and the charging slope. When the sampled value of the target output parameter is within the range of the target output parameter values, the correspondence is expressed as follows: 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 charging slope, I_dis_max represents the maximum discharge current, and I_char_max represents the maximum charging current.

5. The parallel control method for energy storage battery modules according to claim 4, characterized in that, The discharge slope decreases as the SOC value increases, and / or the charging slope increases as the SOC value increases.

6. The parallel control method for energy storage battery modules according to claim 3, characterized in that, The adjustment of 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 includes: In the case where 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 range, the given value of the target output parameter is determined based on 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 range, the given value of the target output parameter is determined to be the maximum value of the target output parameter range; or, when the sampled value of the DC bus voltage is less than the minimum value of the target voltage range, the given value of the target output parameter is determined to be the minimum value of the target output parameter range.

7. A DC / DC converter, characterized in that, The DC / DC converter, used in energy storage battery modules, includes a voltage controller, a drive module, and a main circuit. The voltage controller is used to perform the method of any one of claims 1 to 6 to calculate the drive signal; The drive module is used to receive drive signals from the voltage controller and drive the main circuit.

8. An energy storage battery module, characterized in that, The energy storage battery module includes at least one battery cell and the DC / DC converter as described in claim 7.

9. An energy storage system, characterized in that, The energy storage system includes a DC bus and multiple energy storage battery modules as described in claim 8.

10. A computer device, characterized in that, The computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the method of any one of claims 1 to 6.

11. A chip, characterized in that, The chip is used to perform the method according to any one of claims 1 to 6.

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