Multi-cluster parallel battery inter-cluster dynamic balance control method, controller, multi-cluster parallel battery cluster system and energy storage system

Abstract

The invention relates to a dynamic balance control method between multi-cluster parallel battery clusters, a controller, a multi-cluster parallel battery cluster system and an energy storage system. The method comprises the following steps: acquiring the voltage of each battery cluster; under the condition that the voltage difference value of any two battery clusters is smaller than or equal to a first voltage threshold value, the voltage average value of each battery cluster is determined; if the target battery cluster exists, the working state of a first converter connected with the target battery cluster is controlled according to the difference value between the voltage of the target battery cluster and the voltage average value, so that the target battery cluster is charged or discharged until the difference value between the voltage of any battery cluster and the voltage average value is smaller than or equal to a second voltage threshold value; wherein the difference value between the voltage of the target battery cluster and the voltage average value is greater than the second voltage threshold value, and the first voltage threshold value is greater than the second voltage threshold value. By adopting the method, the balance among the battery clusters can be effectively realized, and the service life of the energy storage system is prolonged.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a dynamic balancing control method among multiple parallel battery clusters, a controller, a multiple parallel battery cluster system, and an energy storage system. Background Art

[0002] In modern energy storage systems, battery clusters are important energy storage units, and their performance directly affects the efficiency and stability of the entire system. In order to meet the growing demand for energy storage, especially for large-scale energy storage projects such as grid-level energy storage systems, it is usually necessary to use multiple battery clusters in parallel to expand the energy storage capacity.

[0003] However, battery clusters used in parallel may have voltage inconsistencies due to differences in manufacturing processes, different degrees of aging, changes in the use environment, and other factors. When the voltages of battery clusters are inconsistent, it will cause uneven current distribution, and some battery clusters may be overloaded, thus affecting the overall performance of the system, shortening the battery life, and even causing safety hazards. Summary of the invention

[0004] Based on this, it is necessary to provide a dynamic balancing control method among multiple parallel battery clusters, a controller, a multiple parallel battery cluster system and an energy storage system to address the above technical issues.

[0005] In a first aspect, the present application provides a method for dynamic balancing control between multiple battery clusters connected in parallel, the method comprising:

[0006] Obtain the voltage of each battery cluster;

[0007] When the voltage difference between any two battery clusters is less than or equal to a first voltage threshold, determining an average voltage value of each battery cluster;

[0008] If there is a target battery cluster, the working state of the first converter connected to the target battery cluster is controlled according to the difference between the voltage of the target battery cluster and the voltage average value, so that the target battery cluster is charged or discharged until the difference between the voltage of any battery cluster and the voltage average value is less than or equal to the second voltage threshold;

[0009] The difference between the voltage of the target battery cluster and the average voltage is greater than the second voltage threshold, and the first voltage threshold is greater than the second voltage threshold.

[0010] In one embodiment, controlling the working state of a first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value includes:

[0011] If the voltages of the target battery clusters are all greater than the average voltage, the first converter connected to the target battery cluster is controlled to operate in a discharging state, and the second converter connected to the storage battery is controlled to operate in a charging state, so that the target battery cluster outputs electrical energy to the storage battery.

[0012] In one embodiment, controlling the working state of a first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value includes:

[0013] If the voltages of the target battery clusters are all lower than the average voltage, the first converter connected to the target battery cluster is controlled to operate in a charging state, and the second converter connected to the storage battery is controlled to operate in a discharging state, so that the target battery cluster receives the electric energy output by the storage battery;

[0014] If the difference between the voltage of the target battery cluster and the voltage average value is still greater than the second voltage threshold, the third converter connected to the AC source is controlled to operate in a discharge state so that the target battery cluster receives the electric energy output by the AC source.

[0015] In one embodiment, controlling the working state of a first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value includes:

[0016] If the voltage of some target battery clusters is greater than the voltage average value, and the voltage of some target battery clusters is less than the voltage average value, the first converter connected to the first battery cluster is controlled to operate in a discharging state, and the first converter connected to the second battery cluster is controlled to operate in a charging state, so that the first battery cluster outputs electric energy to the second battery cluster;

[0017] The first battery cluster is a target battery cluster whose voltage is greater than the average voltage, and the second battery cluster is a target battery cluster whose voltage is less than the average voltage.

[0018] In one embodiment, after the step of controlling the first converter connected to the first battery cluster to operate in a discharging state and controlling the first converter connected to the second battery cluster to operate in a charging state, the method further includes:

[0019] If the difference between the voltage of the target battery cluster and the voltage average value is still greater than the second voltage threshold, the working state of at least one of the second converter connected to the battery and the third converter connected to the AC source is controlled.

[0020] In one embodiment, the method further comprises:

[0021] When the voltage difference between any two battery clusters is greater than a first voltage threshold, the battery clusters are controlled to be connected until the voltage difference between any two battery clusters is less than or equal to the first voltage threshold.

[0022] In one embodiment, controlling each battery cluster to be connected includes:

[0023] The battery clusters are connected in order from the smallest to the largest voltage.

[0024] In one embodiment, connecting the battery clusters in order from the smallest to the largest voltage of the battery clusters includes:

[0025] Connect the first two battery clusters sorted in ascending order of voltage;

[0026] The step of connecting the next battery cluster in ascending order of voltage when the current between the connected battery clusters is less than a preset current threshold is cyclically performed until all the battery clusters are connected.

[0027] In one embodiment, controlling each battery cluster to be connected includes:

[0028] Connect the two battery clusters with the largest voltage difference;

[0029] When the current between the connected battery clusters is less than the preset current threshold, the connection between the battery clusters is disconnected, and the process returns to the step of connecting the two battery clusters with the largest voltage difference.

[0030] In one embodiment, in the presence of a storage battery and an AC source, after the step of controlling the working state of a first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value, the method further includes:

[0031] If the remaining power of the storage battery is less than the preset power, the third converter connected to the AC source is controlled to operate in a discharging state, and the second converter connected to the storage battery is controlled to operate in a charging state.

[0032] In one embodiment, controlling the working state of a first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value includes:

[0033] If the energy storage system is in operation, the first converter connected to the first battery cluster is controlled to operate in a discharging state, and is connected to the first power transmission object according to a preset priority, and the converter connected to the first power transmission object is controlled to operate in a charging state, so that the first battery cluster outputs power to the first power transmission object; and / or,

[0034] Controlling the first converter connected to the second battery cluster to operate in a charging state and accessing the second power transmission object according to a preset priority, and controlling the converter connected to the second power transmission object to operate in a discharging state, so that the second battery cluster receives the power output by the second power transmission object;

[0035] The first battery cluster is a target battery cluster whose voltage is greater than the average voltage, and the second battery cluster is a target battery cluster whose voltage is less than the average voltage;

[0036] The first power transmission target includes one of a storage battery and a second battery cluster, and the second power transmission target includes one of a storage battery, a first battery cluster and an AC source, and the priority of the storage battery is greater than the priority of the target battery cluster, and the priority of the target battery cluster is greater than the priority of the AC source.

[0037] In a second aspect, the present application further provides a controller including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method in the above embodiment when executing the computer program.

[0038] In a third aspect, the present application also provides a multi-cluster parallel battery cluster system, the system comprising:

[0039] A plurality of battery clusters, wherein the plurality of battery clusters are connected in parallel to the first DC bus;

[0040] First converters are connected to the battery clusters one by one, and the first converters are connected to the second DC bus in parallel;

[0041] The controller in the above embodiment is connected to the battery cluster and the first converter respectively.

[0042] In one embodiment, the system further comprises:

[0043] A battery, connected to the controller;

[0044] A second converter, the second converter is connected to the battery, the first DC bus, the second DC bus and the controller respectively;

[0045] AC source;

[0046] The third converter is connected to the second DC bus and the controller respectively.

[0047] In a fourth aspect, the present application further provides an energy storage system, including: a battery cluster system with multiple clusters connected in parallel as in the above embodiment.

[0048] The above-mentioned dynamic balancing control method between multiple parallel battery clusters, controller, multiple parallel battery cluster system and energy storage system have at least the following beneficial effects:

[0049] By setting different voltage thresholds to distinguish different control stages, the system can more accurately judge the voltage difference between battery clusters, thereby achieving more efficient voltage balancing. Specifically, the first voltage threshold is used to determine whether the battery cluster is in an acceptable voltage balance state, while the second voltage threshold is used to trigger further voltage adjustment actions. The dual threshold design enables the system to maintain overall voltage balance while making targeted adjustments to individual battery clusters with large voltage deviations. Through dynamic balancing control, this unbalanced state can be discovered and corrected in a timely manner, avoiding premature failure of certain battery clusters due to overwork, thereby extending the service life of the entire energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0051] FIG1 is a diagram showing an application environment of a method for dynamic balancing control among multiple battery clusters connected in parallel in one embodiment;

[0052] FIG2 is a schematic flow chart of a method for dynamic balancing control among multiple battery clusters connected in parallel in one embodiment;

[0053] 3 is a flow chart of steps for controlling the working state of a first converter connected to a target battery cluster according to a difference between a voltage of the target battery cluster and an average voltage in one embodiment;

[0054] FIG4 is a schematic flow chart of a method for dynamic balancing control among multiple battery clusters connected in parallel in another embodiment;

[0055] FIG5 is a schematic flow chart of the steps of connecting the battery clusters in order from the smallest to the largest voltage of the battery clusters in one embodiment;

[0056] FIG6 is a schematic diagram of a flow chart of steps for controlling the connection of each battery cluster in one embodiment;

[0057] FIG7 is a structural block diagram of a device for dynamically balancing multiple battery clusters in parallel in one embodiment;

[0058] FIG. 8 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0060] The dynamic balancing control method between multiple parallel battery clusters provided in the embodiment of the present application can be applied to the energy storage system shown in Figure 1. The energy storage system may include multiple battery clusters (such as RACK1, RACK2 and RACKn, etc.), a first DC bus DC_BUS-1, a second DC bus DC_BUS-2, multiple first converters and controllers. Each battery cluster also includes an energy storage unit, multiple switches (such as KM1, KM2 and KM3) and a battery management system (not shown in the figure). The energy storage units in each battery cluster are connected in parallel to the first DC bus DC_BUS-1 through multiple switches. In addition, the energy storage units in each battery cluster are also connected in parallel to the second DC bus DC_BUS-2 through the first converters connected thereto one by one. In addition, the energy storage system may also include a battery, an AC source, a second converter and a third converter, wherein the battery may be simultaneously connected to the first DC bus DC_BUS-1 and the second DC bus DC_BUS-2 through the second converter, so that the battery and the plurality of battery clusters are connected in parallel; the AC source may be connected to the second DC bus DC_BUS-2 through the third converter, so that the AC source and the battery and the plurality of battery clusters are connected in parallel. The controller is respectively connected in communication with the plurality of battery clusters, the plurality of first converters, the second converter, the battery, the third converter and the AC source, and may monitor and adjust the equipment operation parameters. The controller obtains the voltage of each battery cluster; when the voltage difference between any two battery clusters is less than or equal to a first voltage threshold, the average voltage of each battery cluster is determined; if a target battery cluster exists, the working state of the first converter connected to the target battery cluster is controlled according to the difference between the voltage of the target battery cluster and the voltage average value, so that the target battery cluster is charged or discharged (such as charging through a battery and an AC source, and discharging to other battery clusters outside the battery or the target battery cluster) until the difference between the voltage of any battery cluster and the voltage average value is less than or equal to a second voltage threshold; wherein the difference between the voltage of the target battery cluster and the voltage average value is greater than the second voltage threshold, and the first voltage threshold is greater than the second voltage threshold, thereby completing the balancing between the battery clusters.

[0061] In an exemplary embodiment, as shown in FIG2 , a method for dynamic balancing control between multiple parallel battery clusters is provided, and the method is described by taking the controller in FIG1 as an example, including the following steps S202 to S206 . Among them:

[0062] S202, obtaining the voltage of each battery cluster;

[0063] S204, when the voltage difference between any two battery clusters is less than or equal to a first voltage threshold, determining an average voltage value of each battery cluster;

[0064] The voltage of each battery cluster can be acquired by communicating with the battery management system of each battery cluster. The voltage difference between two battery clusters can refer to the absolute value of the value obtained by subtracting the two battery clusters, which is used to characterize the voltage difference between the two battery clusters. In addition to being expressed in absolute values, the voltage difference between the two battery clusters can also be expressed in a ratio. The first voltage threshold is used to determine whether the voltage difference between the battery clusters is small enough, and based on this, determine whether the battery clusters are in a relatively balanced state. When the voltage difference between any two battery clusters is less than or equal to the first voltage threshold, it means that the voltages of the battery clusters are relatively close. At this time, a global voltage average value can be calculated as a reference value for further voltage balancing between battery clusters to improve the precision of voltage balancing between battery clusters.

[0065] S206, if there is a target battery cluster, then according to the difference between the voltage of the target battery cluster and the voltage average value, the working state of the first inverter connected to the target battery cluster is controlled to charge or discharge the target battery cluster until the difference between the voltage of any battery cluster and the voltage average value is less than or equal to the second voltage threshold; wherein the difference between the voltage of the target battery cluster and the voltage average value is greater than the second voltage threshold, and the first voltage threshold is greater than the second voltage threshold.

[0066] The difference between the voltage of the target battery cluster and the voltage average value may also refer to the absolute value of the value obtained by subtracting the voltage of the battery cluster from the voltage average value, which is used to characterize the voltage difference between the voltage of the battery cluster and the voltage average value. The second voltage threshold refers to another threshold used to determine whether a certain battery cluster needs to be adjusted in voltage. It should be noted that the second voltage threshold is a threshold less than the first voltage threshold. By setting the second voltage threshold less than the first voltage threshold, the voltage balancing effect between battery clusters can be further accurately controlled. The balancing is completed only when the difference between the voltage of any battery cluster and the voltage average value is less than or equal to the second voltage threshold. The target battery cluster is a battery cluster in which the difference between the voltage of at least one battery cluster and the calculated voltage average value exceeds the second voltage threshold, which means that the battery cluster needs to be adjusted. At this time, according to this gap, the charging or discharging operation will be performed by adjusting the working state of the first converter connected to the battery cluster until the gap is reduced to less than or equal to the second voltage threshold.

[0067] For example, taking the energy storage system shown in FIG1 as an example, before the energy storage system starts running, the controller can communicate with the battery to collect the voltage of each battery cluster, and compare the voltage difference between any two battery clusters to determine the balance between the battery clusters. If the voltage difference between any two battery clusters is greater than the first voltage threshold, it means that the voltage difference between the battery clusters is too large and the balance is poor. At this time, even if more precise balance control is performed, the balance effect will not be very good, so preliminary balance is required until the voltage difference between any two battery clusters is less than or equal to the first voltage threshold. Then, the voltage average value of each battery cluster is determined when the voltage difference between any two battery clusters is less than or equal to the first voltage threshold, and the voltage of each battery cluster is compared with the voltage average value to determine whether there is a battery cluster in each battery cluster whose voltage difference with the voltage average value is greater than the second voltage threshold. If such a battery cluster exists, the battery cluster can be controlled to discharge to other battery clusters or to storage batteries according to the difference between the voltage of the battery cluster and the voltage average value to reduce the voltage of the battery cluster; or the battery cluster can be controlled to draw power from other battery clusters or storage batteries or AC sources except the battery cluster to supplement the electric energy of the battery cluster, thereby increasing the voltage of the battery cluster, until the difference between the voltage of any battery cluster and the voltage average value is less than or equal to the second voltage threshold, and balancing is completed.

[0068] The above-mentioned dynamic balancing control method between multiple parallel battery clusters distinguishes different control stages by setting different voltage thresholds, so that the system can more accurately judge the voltage difference between battery clusters, thereby achieving more efficient voltage balancing. Specifically, the first voltage threshold is used to determine whether the battery cluster is in an acceptable voltage balancing state, while the second voltage threshold is used to trigger further voltage adjustment actions. The dual threshold design enables the system to make targeted adjustments to individual battery clusters with large voltage deviations while maintaining overall voltage balance. Through dynamic balancing control, this unbalanced state can be discovered and corrected in a timely manner, avoiding premature failure of certain battery clusters due to overwork, thereby extending the service life of the entire energy storage system.

[0069] In an exemplary embodiment, as shown in FIG3 , controlling the working state of the first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value includes:

[0070] S302, if the voltages of the target battery clusters are all greater than the average voltage, control the first converter connected to the target battery cluster to operate in a discharging state, and control the second converter connected to the storage battery to operate in a charging state, so that the target battery cluster outputs electrical energy to the storage battery.

[0071] For example, taking the energy storage system in FIG1 as an example, assuming that the first voltage threshold △U1=3V, the second voltage threshold △U2=0.5V, and the voltages of the battery clusters are: Rack1: 750Vdc, Rack2: 751Vdc, Rack3: 750Vdc, Rack4: 750Vdc, Rack5: 750Vdc, it is obvious that the voltage difference between any two battery clusters is less than or equal to the first voltage threshold △U1=3V, and the average voltage U is calculated. ave =750.2Vdc, where only the difference between the voltage of Rack2 and the average voltage is greater than the second voltage threshold, i.e. |U Rack2 -U ave |>△U2, Rack2 is the target battery cluster, and the voltage of Rack2 is greater than the average voltage, indicating that Rack2 has excess power and too high voltage.

[0072] Since the difference between the voltage of the battery clusters (Rack1, Rack3, Rack4, Rack5) except Rack2 and the voltage average value is less than or equal to the second voltage threshold, it can be seen that the inter-cluster voltage of the battery clusters (Rack1, Rack3, Rack4, Rack5) except Rack2 has reached a relative balance. If the electric energy of Rack2 is output to the battery clusters (Rack1, Rack3, Rack4, Rack5) except Rack2 at this time, the relatively balanced inter-cluster voltage will be broken, causing the balancing adjustment to become more complicated. Therefore, at this time, by introducing energy storage devices such as batteries as shown in Figure 1, based on the control of the controller, the first converter connected to the target battery cluster is operated in a discharge state, and the second converter connected to the battery is operated in a charging state, so that Rack2 outputs electric energy to the battery until the difference between the voltage of Rack2 and the voltage average value is less than or equal to the second voltage threshold △U2, thereby quickly achieving higher-precision voltage balancing between battery clusters.

[0073] In this embodiment, by introducing a storage battery as an external energy storage device and combining it with a precise voltage threshold control strategy, voltage balancing in a multi-cluster parallel battery system can be effectively achieved, which not only avoids the problem of inter-cluster voltage imbalance that may be caused by direct energy transfer between battery clusters, but also can quickly respond and adjust the voltage of a single battery cluster to ensure that the difference between it and the system average voltage is maintained within a smaller range, thereby improving the voltage balancing accuracy and operating stability of the entire system and extending the battery life.

[0074] In an exemplary embodiment, as shown in FIG3 , controlling the working state of the first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value includes:

[0075] S304, if the voltages of the target battery clusters are all lower than the voltage average, control the first converter connected to the target battery cluster to operate in a charging state, and control the second converter connected to the storage battery to operate in a discharging state, so that the target battery cluster receives the electric energy output by the storage battery.

[0076] S306: If the difference between the voltage of the target battery cluster and the voltage average value is still greater than the second voltage threshold, control the third converter connected to the AC source to operate in a discharge state so that the target battery cluster receives the electric energy output by the AC source.

[0077] For example, still taking the energy storage system in FIG1 as an example, assuming that the first voltage threshold △U1=3V, the second voltage threshold △U2=0.5V, and assuming that the voltages of the battery clusters are: Rack1: 750Vdc, Rack2: 749Vdc, Rack3: 750Vdc, Rack4: 750Vdc, Rack5: 750Vdc, it is obvious that at this time, the voltage difference between any two battery clusters is less than or equal to the first voltage threshold △U1=3V, and the calculated voltage average value U ave =749.8Vdc, where only the difference between the voltage of Rack2 and the average voltage is greater than the second voltage threshold, i.e. |U Rack2 -U ave |>△U2, Rack2 is the target battery cluster, and the voltage of Rack2 is less than the average voltage, which means that the power of Rack2 is insufficient and the voltage is too low.

[0078] Similarly, since the difference between the voltage of the battery clusters (Rack1, Rack3, Rack4, Rack5) except Rack2 and the voltage average value is less than or equal to the second voltage threshold, the inter-cluster voltage of the battery clusters (Rack1, Rack3, Rack4, Rack5) except Rack2 has reached a relative balance. If the electric energy of Rack2 is output to the battery clusters (Rack1, Rack3, Rack4, Rack5) except Rack2 at this time, the relatively balanced inter-cluster voltage will be broken, causing the balancing adjustment to become more complicated. Therefore, at this time, by introducing energy storage devices such as batteries as shown in Figure 1, based on the control of the controller, the first converter connected to the target battery cluster is operated in a charging state, and the second converter connected to the battery is operated in a discharging state, so that Rack2 receives the electric energy output by the battery until the difference between the voltage of Rack2 and the voltage average value is less than or equal to the second voltage threshold △U2, thereby quickly achieving higher-precision voltage balancing between battery clusters.

[0079] After Rack2 is supplemented with electric energy through the battery, if the difference between the voltage of Rack2 and the voltage average value is still greater than the second voltage threshold, an AC source can be further introduced. Based on the control of the controller, the third inverter connected to the AC source is operated in a discharge state so that the target battery cluster receives the electric energy output by the AC source until the difference between the voltage of Rack2 and the voltage average value is less than or equal to the second voltage threshold △U2.

[0080] In this embodiment, when the voltage of a battery cluster (target battery cluster) is lower than the average voltage of each battery cluster and exceeds the second voltage threshold, the battery cluster is first charged by the storage battery to quickly increase its voltage to a value close to the average value. If the voltage of the target battery cluster is still lower than the second voltage threshold after the storage battery is charged, it is further powered by an AC source to ensure that accurate voltage balancing is ultimately achieved, which not only avoids the voltage imbalance between clusters that may be caused by directly transferring electric energy between battery clusters, but also enables the flexible use of multiple energy sources to improve the response speed and adjustment accuracy of the system, thereby significantly improving the stability and efficiency of the entire energy storage system, while extending the service life of the battery.

[0081] In an exemplary embodiment, as shown in FIG3 , controlling the working state of the first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value includes:

[0082] S308, if the voltage of some target battery clusters is greater than the voltage average value, and the voltage of some target battery clusters is less than the voltage average value, control the first converter connected to the first battery cluster to operate in a discharging state, and control the first converter connected to the second battery cluster to operate in a charging state, so that the first battery cluster outputs electric energy to the second battery cluster;

[0083] The first battery cluster is a target battery cluster whose voltage is greater than the average voltage, and the second battery cluster is a target battery cluster whose voltage is less than the average voltage.

[0084] For example, still taking the energy storage system in FIG1 as an example, assuming that the first voltage threshold △U1=3V, the second voltage threshold △U2=0.5V, and assuming that the voltages of the battery clusters are: Rack1: 750Vdc, Rack2: 749Vdc, Rack3: 751Vdc, Rack4: 751Vdc, Rack5: 750Vdc, it is obvious that at this time, the voltage difference between any two battery clusters is less than or equal to the first voltage threshold △U1=3V, and the calculated voltage average value U ave =750.2Vdc, where Rack2: 749Vdc, Rack3: 751Vdc, Rack4: 751Vdc and the average voltage U aveThe differences are all greater than the second voltage threshold, and the voltage of Rack2 is less than the voltage average, and the voltages of Rack3 and Rack4 are greater than the voltage average, that is, Rack3 and Rack4 are the first battery clusters, and Rack2 is the second battery cluster.

[0085] The controller controls the first converters corresponding to Rack3 and Rack4 to operate in a discharging state to release electric energy to the second DC bus DC_BUS-2. The controller controls the first converter corresponding to Rack2 to operate in a charging state to obtain electric energy from the second DC bus DC_BUS-2 for replenishment until the difference between the voltage of Rack2, the voltage of Rack3 and the voltage of Rack4 and the average voltage is less than the second voltage threshold (such as Rack2=750Vdc, Rack3=750.2Vdc, Rack4=750.3Vdc).

[0086] In this embodiment, efficient voltage balancing control is achieved by directly transferring electric energy between battery clusters with uneven voltages. When the voltage of some battery clusters in the system is higher than the average voltage and the voltage of others is lower than the average voltage, the working state of the relevant converter is controlled so that the high-voltage battery cluster transmits electric energy to the low-voltage battery cluster, thereby quickly reducing the voltage difference between the battery clusters. This not only avoids the complexity and cost of introducing additional energy storage equipment, but also improves the response speed and energy utilization efficiency of the system, ensures that the voltage between battery clusters is more uniform, and thus improves the stability and reliability of the entire energy storage system.

[0087] In an exemplary embodiment, after the step of controlling the first converter connected to the first battery cluster to operate in a discharging state and controlling the first converter connected to the second battery cluster to operate in a charging state, the method further includes:

[0088] S310: If the difference between the voltage of the target battery cluster and the voltage average value is still greater than the second voltage threshold, control the working state of at least one of the second converter connected to the battery and the third converter connected to the AC source.

[0089] Exemplarily, taking the voltages of the battery clusters in the above embodiment as follows: Rack1: 750 Vdc, Rack2: 749 Vdc, Rack3: 751 Vdc, Rack4: 751 Vdc, Rack5: 750 Vdc as an example, when controlling the first converters corresponding to Rack3 and Rack4 to operate in a discharging state and release electric energy to the second DC bus DC_BUS-2, the controller controls the first converter corresponding to Rack2 to operate in a charging state and obtain electric energy from the second DC bus DC_BUS-2 for power replenishment. In the balancing process, if the energy between Rack2, Rack3, and Rack4 cannot meet the requirement of reaching a balanced value, it can be obtained from the battery and / or the AC source or fed back to the battery until the difference between the voltage of Rack2, the voltage of Rack3, and the voltage of Rack4 and the average voltage is less than the second voltage threshold.

[0090] In this embodiment, multi-level voltage balancing control is achieved by combining direct energy exchange between battery clusters with the assistance of external energy sources (such as batteries and AC sources). When the energy transfer within the battery cluster is insufficient to achieve voltage balancing, external energy support can be automatically introduced to ensure that the voltage of the target battery cluster can be quickly adjusted, which not only improves the accuracy and speed of voltage balancing, but also enhances the flexibility and reliability of the system, thereby effectively extending the service life of the battery and ensuring the overall stability and efficient operation of the energy storage system.

[0091] In an exemplary embodiment, as shown in FIG4 , the method further includes:

[0092] S402 : When the voltage difference between any two battery clusters is greater than a first voltage threshold, control the battery clusters to be connected until the voltage difference between any two battery clusters is less than or equal to the first voltage threshold.

[0093] Exemplarily, as described in the above embodiment, if the voltage difference between any two battery clusters is greater than the first voltage threshold, it means that the voltage difference between the battery clusters is too large and the balance is poor. At this time, even if more precise balance control is performed, the balance effect will not be very good, so preliminary balance is required. Taking the energy storage system shown in Figure 1 as an example, by controlling the on and off of multiple switches (such as KM1, KM2 and KM3) corresponding to each battery cluster, each battery cluster can be connected in parallel to the first DC bus DC_BUS-1, so that each battery cluster is preliminarily balanced based on its own voltage difference until the voltage difference between any two battery clusters is less than or equal to the first voltage threshold.

[0094] In this embodiment, by performing preliminary balancing control when the voltage difference between battery clusters is too large, the overall balancing efficiency and accuracy of the system are effectively improved. When the voltage difference between any two battery clusters is greater than the first voltage threshold, by controlling the switches corresponding to each battery cluster, they are connected in parallel to the same DC bus, and the natural energy flow between the battery clusters is used for preliminary balancing, which can quickly reduce the voltage difference in a short time, laying the foundation for subsequent more refined balancing control, thereby ensuring that the voltage of the entire energy storage system is more uniform and stable, and improving the overall performance and reliability of the system.

[0095] In an exemplary embodiment, controlling each battery cluster to be connected includes:

[0096] The battery clusters are connected in order from the smallest to the largest voltage.

[0097] For example, taking the energy storage system shown in FIG1 as an example, assuming that the battery clusters are Rack1-Rack5, the voltages of each battery cluster are: Rack1: 745Vdc, Rack2: 747Vdc, Rack3: 755Vdc, Rack4: 754Vdc, Rack5: 750Vdc, and the first voltage threshold △U1=3V. Obviously, the voltage difference between Rack1: 745Vdc and Rack3: 755Vdc is 10Vdc, which is greater than the first voltage threshold △U1=3V. At this time, the first DC bus DC_BUS-1 can be connected in the order of Rack1→Rack2→Rack5→Rack4→Rack3, so that each battery cluster is preliminarily balanced based on its own voltage difference until the voltage difference between any two battery clusters is less than or equal to the first voltage threshold. Among them, when connecting the battery clusters in order from small to large according to the voltage of the battery clusters, the connection time interval between two adjacent battery clusters can be set to ensure that the battery cluster connected first can be preliminarily balanced first. The current between the battery clusters can also be monitored. After the current between the battery clusters connected first reaches a certain value, the next battery cluster can be connected, which can also ensure that the battery cluster connected first can be preliminarily balanced first.

[0098] In this embodiment, by connecting the battery clusters in order from low to high voltage, it can be ensured that each time a new battery cluster is connected, the voltage difference between the battery cluster and the already connected battery cluster will not be too large, thereby reducing the large current impact caused by voltage mutation, protecting the safety of the battery cluster and the system, and not only improving the stability and reliability of the system, but also being able to achieve the required voltage balance state more quickly, thereby improving the efficiency and performance of the entire energy storage system.

[0099] In an exemplary embodiment, as shown in FIG5 , connecting the battery clusters in order from the smallest to the largest voltage of the battery clusters includes:

[0100] S502 , connecting the first two battery clusters sorted in ascending order of voltage.

[0101] S504 , cyclically executing the step of connecting the next battery cluster in ascending order of voltage when the current between the connected battery clusters is less than a preset current threshold, until all the battery clusters are connected.

[0102] For example, taking the energy storage system shown in FIG1 as an example, assuming that the battery clusters are Rack1-Rack5, the voltages of each battery cluster are: Rack1: 745Vdc, Rack2: 747Vdc, Rack3: 755Vdc, Rack4: 754Vdc, Rack5: 750Vdc, and the first voltage threshold △U1 = 3V. Obviously, the voltage difference between Rack1: 745Vdc and Rack3: 755Vdc is 10Vdc, which is greater than the first voltage threshold △U1 = 3V. At this time, the two battery clusters with the lowest voltage are closed first: Rack1 and Rack2, for balancing. When the current between Rack1 and Rack2 is less than the preset current threshold I1, balancing is completed. At this time, the battery cluster voltages are: Rack1: 745.8Vdc, Rack2: 746Vdc; Rack1 and Rack2 are kept in a closed state, and then the battery cluster Rack5 with the third lowest voltage is closed for balancing. After balancing is completed, Rack1, Rack2, and Rack5 are kept in a closed state, and the battery cluster Rack4 with the fourth lowest voltage is closed, and so on until all battery clusters are closed and connected to the first DC bus DC BUS-1 for balancing. After balancing is completed, the switches KM2 and KM3 in each battery cluster are disconnected to keep the system in standby mode.

[0103] In this embodiment, by connecting each battery cluster in order from small to large in terms of battery cluster voltage, and ensuring that the current between the connected battery clusters reaches a preset threshold before connecting each new battery cluster, a smooth and efficient initial balance is achieved, which can effectively avoid large current shocks caused by excessive voltage differences, protect the safety of the battery cluster and the system, and ensure that each newly connected battery cluster can be smoothly integrated with the balanced battery cluster, ultimately achieving voltage balance for the entire system.

[0104] In an exemplary embodiment, as shown in FIG6 , controlling each battery cluster to be connected includes:

[0105] S602, connecting two battery clusters with the largest voltage difference.

[0106] S604, when the current between the connected battery clusters is less than the preset current threshold, disconnect the battery clusters, and return to the step of connecting the two battery clusters with the largest voltage difference.

[0107] For example, taking the energy storage system shown in FIG1 as an example, the battery clusters are Rack1-Rack5, and the voltages of each battery cluster are: Rack1: 745Vdc, Rack2: 747Vdc, Rack3: 755Vdc, Rack4: 754Vdc, Rack5: 750Vdc; △U1 = 3V. The two battery clusters with the largest voltage difference in the first group and greater than the first voltage threshold △U1 are found to be Rack1: 745Vdc and Rack3: 755Vdc, and the voltage difference is 10Vdc. Close KM2 and KM3 of Rack1 and Rack3 to balance Rack1 and Rack3 through the first DC bus DC_BUS-1. When the current between Rack1 and Rack3 is less than the preset current threshold I1, it is considered that the balance is completed. After the balance, the voltages are Rack1: 750Vdc, Rack3: 751Vdc, and KM2 and KM3 of Rack1 and Rack3 are disconnected. At this time, the voltages of Rack1-Rack5 are Rack1: 750Vdc, Rack2: 747Vdc, Rack3: 751Vdc, Rack4: 754Vdc, Rack5: 750Vdc;

[0108] Find the second group of two battery clusters with the largest voltage difference and greater than the first voltage threshold △U1, which are Rack2: 747Vdc and Rack4: 754Vdc, with a voltage difference of 7Vdc. Close KM2 and KM3 of Rack2 and Rack4 to balance Rack2 and Rack4 through the first DC bus DC_BUS-1. When the current between Rack2 and Rack4 is less than the preset current threshold I1, it is considered that the balancing is completed. After balancing, the voltages of Rack2: 749Vdc and Rack4: 751Vdc. At this time, the voltages of Rack1-Rack5 are Rack1: 750Vdc, Rack2: 749Vdc, Rack3: 751Vdc, Rack4: 751Vdc, and Rack5: 750Vdc. Repeat this process until the voltage difference between any two battery clusters in Rack1-Rack5 is less than or equal to the first voltage threshold.

[0109] In this embodiment, the two battery clusters with the largest voltage difference are connected for preliminary balancing, and the connection is disconnected after the balancing is completed, and then the two new battery clusters with the largest voltage difference are continuously searched for balancing, until the voltage difference of all battery clusters is less than or equal to the first voltage threshold, which can effectively gradually reduce the maximum voltage difference in the system, avoid the large current shock that may be caused by directly connecting all battery clusters, and thus improve the stability and safety of the system. At the same time, by cyclically executing the connection and disconnection process, it is ensured that each balancing is carried out within a controllable range, achieving voltage balancing of the entire system, and improving the overall performance and reliability of the energy storage system.

[0110] In an exemplary embodiment, in the presence of a storage battery and an AC source, after the step of controlling the working state of a first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value, the method further includes:

[0111] If the remaining power of the storage battery is less than the preset power, the third converter connected to the AC source is controlled to operate in a discharging state, and the second converter connected to the storage battery is controlled to operate in a charging state.

[0112] In this embodiment, the remaining power of the battery is monitored and automatically switched to the AC source to charge the battery when the remaining power is lower than a preset value, thereby ensuring that the battery is always in a sufficient state to support voltage balancing between battery clusters at any time. This not only improves the energy management efficiency of the system, but also enhances the stability and reliability of the system, ensuring that the energy storage system can maintain a good operating state under various working conditions.

[0113] In an exemplary embodiment, controlling the working state of a first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value includes:

[0114] If the energy storage system is in operation, the first converter connected to the first battery cluster is controlled to operate in a discharging state, and connected to the first power transmission object according to a preset priority, and the converter connected to the first power transmission object is controlled to operate in a charging state, so that the first battery cluster outputs power to the first power transmission object; and / or, the first converter connected to the second battery cluster is controlled to operate in a charging state, and connected to the second power transmission object according to a preset priority, and the converter connected to the second power transmission object is controlled to operate in a discharging state, so that the second battery cluster receives the power output by the second power transmission object;

[0115] Among them, the first battery cluster is a target battery cluster whose voltage is greater than the voltage average, and the second battery cluster is a target battery cluster whose voltage is less than the voltage average; the first power transmission object includes one of the storage battery and the second battery cluster, and the second power transmission object includes one of the storage battery, the first battery cluster and the AC source, and the priority of the storage battery is greater than the priority of the target battery cluster, and the priority of the target battery cluster is greater than the priority of the AC source.

[0116] The energy storage system being in operation state may mean that the energy storage system absorbs electrical energy from an external power source (such as the power grid, solar photovoltaic panels, wind power generation, etc.) and stores it in a battery cluster; or the energy storage system is in the process of providing electrical energy to a load (such as the power grid, household appliances, industrial equipment, etc.), that is, releasing the electrical energy stored in the battery cluster for use.

[0117] For example, taking the energy storage system shown in FIG1 as an example, if the energy storage system is in operation, assuming that the voltages of the battery clusters are Rack1: 750Vdc, Rack2: 749Vdc, Rack3: 750Vdc, Rack4: 750Vdc, Rack5: 750Vdc, the first voltage threshold △U1=3V, and the second voltage threshold △U2=0.5V. Obviously, at this time, the voltage difference between any two battery clusters is less than or equal to the first voltage threshold △U1=3V, and the calculated voltage average value U ave =750.2Vdc, the difference between the voltage of Rack2 and the average voltage is greater than the second preset threshold, and the voltage of Rack2 is less than the average voltage, that is, Rack2 is the second battery cluster. The voltage of Rack2 is low, which may cause the output current of Rack2 to be small during the operation of the energy storage system. For example, the output currents are Rack1: 100.5A, Rack2: 98A, Rack3: 100.5A, Rack4: 100.5A, Rack5: 100.5A, respectively. The controller controls the first converter corresponding to Rack2 to work in the charging state, and the battery or the first battery cluster or the AC source provides power, wherein the priority order of power supply is battery → first battery cluster → AC source. Since the first battery cluster does not exist in Rack1-5 at this time, the second converter connected to the storage battery or the third converter connected to the AC source can be controlled to work in a discharge state, so that Rack2 receives the electric energy output by the storage battery or the AC source, so that the output currents of each battery cluster are respectively Rack1: 100 A, Rack2: 100 A, Rack3: 100 A, Rack4: 100 A, Rack5: 100 A. The electric energy provided by the storage battery or the first battery cluster or the AC source can be adjusted in real time according to the voltage of Rack2 and the output current value until the voltage of Rack1-5 is balanced, that is, the difference between the voltage of any battery cluster and the voltage average value is less than or equal to the second voltage threshold, and then the balancing is stopped.

[0118] On the contrary, if the voltage of a battery cluster is too high and the output current is too large, the electric energy of the battery cluster is transferred to the storage battery for balancing. Specifically, if the energy storage system is in operation, assuming that the voltages of the battery clusters are Rack1: 750Vdc, Rack2: 751Vdc, Rack3: 750Vdc, Rack4: 750Vdc, Rack5: 750Vdc, the first voltage threshold △U1=3V, the second voltage threshold △U2=0.5V, obviously, at this time, the voltage difference between any two battery clusters is less than or equal to the first voltage threshold △U1=3V, and the calculated voltage average value U ave=750.2Vdc, where only the difference between the voltage of Rack2 and the average voltage is greater than the second voltage threshold, and the voltage of Rack2 is greater than the average voltage, that is, Rack2 is the first battery cluster. The voltage of Rack2 is low, which may cause the output current of Rack2 to be small during the operation of the energy storage system. The controller controls the first converter corresponding to Rack2 to work in the discharge state, and the battery or the second battery cluster receives the electric energy, where the priority order of electric energy reception is battery → second battery cluster. Since there is no second battery cluster in Rack1-5 at this time, it is sufficient to control the charging state of the second converter connected to the battery so that Rack2 outputs electric energy to the battery to achieve voltage balance.

[0119] Secondly, in the case where the target battery cluster includes both the first battery cluster and the second battery cluster, the battery can be used preferentially to participate in the balancing of the target battery cluster based on the fact that the priority of the battery is greater than the priority of the target battery cluster and the priority of the target battery cluster is greater than the priority of the AC source. Based on the faster response speed of the battery, it can quickly provide or absorb electric energy, thereby achieving rapid balancing. Subsequently, the first battery cluster or the second battery cluster is used to participate in the balancing of the target battery cluster, and finally the AC source is used to participate in the balancing of the target battery cluster. This can avoid the resonance problem caused by the direct connection of the AC source and the battery cluster as much as possible.

[0120] In this embodiment, by giving priority to using storage batteries to participate in the balancing of the target battery cluster, the rapid response capability and high efficiency of the storage batteries are fully utilized, and the voltage of the battery cluster can be quickly adjusted to ensure that the voltage and current of each battery cluster tend to be consistent during system operation, thereby improving the overall stability and efficiency of the system. It not only reduces the resonance problem that may be caused by directly obtaining electric energy from the AC source, but also ensures the rapid response and smooth operation of the system through a hierarchical power transmission strategy, ultimately achieving efficient balancing between battery clusters and extending the service life of the battery clusters.

[0121] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0122] Based on the same inventive concept, the embodiment of the present application also provides a device for dynamically balancing multiple battery clusters in parallel for implementing the method for dynamically balancing multiple battery clusters in parallel. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the method above, so the specific limitations in the embodiments of one or more devices for dynamically balancing multiple battery clusters in parallel provided below can refer to the limitations of the method for dynamically balancing multiple battery clusters in parallel above, and will not be repeated here.

[0123] In an exemplary embodiment, as shown in FIG. 7 , a dynamic balancing control device for multiple battery clusters connected in parallel is provided, comprising: a battery cluster voltage acquisition module 702 , a voltage average value determination module 704 and a first balancing module 706 , wherein:

[0124] A battery cluster voltage acquisition module 702 is used to acquire the voltage of each battery cluster;

[0125] A voltage average value determination module 704, configured to determine the voltage average value of each battery cluster when the voltage difference between any two battery clusters is less than or equal to a first voltage threshold;

[0126] A first balancing module 706 is used to control the working state of the first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value when there is a target battery cluster, so as to charge or discharge the target battery cluster until the difference between the voltage of any battery cluster and the voltage average value is less than or equal to a second voltage threshold;

[0127] The difference between the voltage of the target battery cluster and the average voltage is greater than the second voltage threshold, and the first voltage threshold is greater than the second voltage threshold.

[0128] In an exemplary embodiment, the first equalization module 706 includes:

[0129] The first balancing unit is used to control the first converter connected to the target battery cluster to operate in a discharging state and the second converter connected to the storage battery to operate in a charging state when the voltage of the target battery cluster is greater than the voltage average value, so that the target battery cluster outputs electric energy to the storage battery.

[0130] In an exemplary embodiment, the first balancing module 706 further includes:

[0131] The second balancing unit is used for controlling the first converter connected to the target battery cluster to operate in a charging state and controlling the second converter connected to the storage battery to operate in a discharging state when the voltages of the target battery clusters are all lower than the voltage average value, so that the target battery cluster receives the electric energy output by the storage battery;

[0132] The third balancing unit is used to control the third converter connected to the AC source to operate in a discharging state when the difference between the voltage of the target battery cluster and the voltage average value is still greater than the second voltage threshold, so that the target battery cluster receives the electric energy output by the AC source.

[0133] In an exemplary embodiment, the first balancing module 706 further includes:

[0134] a fourth balancing unit, configured to control the first converter connected to the first battery cluster to operate in a discharging state, and control the first converter connected to the second battery cluster to operate in a charging state, so that the first battery cluster outputs electric energy to the second battery cluster, when the voltage of some target battery clusters is greater than the voltage average value and the voltage of some target battery clusters is less than the voltage average value;

[0135] The first battery cluster is a target battery cluster whose voltage is greater than the average voltage, and the second battery cluster is a target battery cluster whose voltage is less than the average voltage.

[0136] In an exemplary embodiment, the first balancing module 706 further includes:

[0137] The fifth balancing unit is used to control the working state of at least one of the second converter connected to the battery and the third converter connected to the AC source when the difference between the voltage of the target battery cluster and the voltage average value is still greater than the second voltage threshold.

[0138] In an exemplary embodiment, the device for dynamic balancing control between multiple battery clusters connected in parallel further includes:

[0139] The second balancing module is used to control the battery clusters to be connected when the voltage difference between any two battery clusters is greater than the first voltage threshold, until the voltage difference between any two battery clusters is less than or equal to the first voltage threshold.

[0140] In an exemplary embodiment, the second balancing module includes:

[0141] The connection control unit is used to connect the battery clusters in order from the smallest to the largest voltage of the battery clusters.

[0142] In an exemplary embodiment, the communication control unit includes:

[0143] A first connecting unit is used to connect the first two battery clusters sorted in ascending order of voltage;

[0144] The second connecting unit is used to cyclically execute the step of connecting the next battery cluster in ascending order of voltage when the current between the connected battery clusters is less than a preset current threshold value, until all the battery clusters are connected.

[0145] In an exemplary embodiment, the second balancing module further includes:

[0146] A third connecting unit, used for connecting two battery clusters with the largest voltage difference;

[0147] The fourth connecting unit is used to disconnect the battery clusters when the current between the connected battery clusters is less than a preset current threshold, and return to the step of connecting the two battery clusters with the largest voltage difference.

[0148] In an exemplary embodiment, when there are batteries and AC sources, the first balancing module 706 further includes:

[0149] The charging unit is used to control the third converter connected to the AC source to operate in a discharging state and control the second converter connected to the battery to operate in a charging state when the remaining power of the battery is less than a preset power.

[0150] In an exemplary embodiment, the first balancing module 706 further includes:

[0151] A sixth balancing unit is used to control the first converter connected to the first battery cluster to operate in a discharging state and access the first power transmission object according to a preset priority when the energy storage system is in operation, and control the converter connected to the first power transmission object to operate in a charging state so that the first battery cluster outputs power to the first power transmission object; and / or control the converter connected to the second power transmission object to operate in a discharging state and access the second power transmission object according to a preset priority, and control the first converter connected to the second battery cluster to operate in a charging state so that the second battery cluster receives the power output by the second power transmission object;

[0152] The first battery cluster is a target battery cluster whose voltage is greater than the average voltage, and the second battery cluster is a target battery cluster whose voltage is less than the average voltage;

[0153] The first power transmission target includes one of a storage battery and a second battery cluster, and the second power transmission target includes one of a storage battery, a first battery cluster and an AC source, and the priority of the storage battery is greater than the priority of the target battery cluster, and the priority of the target battery cluster is greater than the priority of the AC source.

[0154] Each module in the above-mentioned multi-cluster parallel battery cluster dynamic balancing control device can be implemented in whole or in part by software, hardware and their combination. Each of the above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the corresponding operations of each of the above modules.

[0155] In an exemplary embodiment, a computer device is provided, which may be a controller, and its internal structure diagram may be shown in FIG8. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data such as the voltage of the battery cluster and the current between the battery clusters. The input / output interface of the computer device is used to exchange information between the processor and the external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a dynamic balancing control method between battery clusters in parallel is implemented.

[0156] Those skilled in the art will understand that the structure shown in FIG. 8 is merely a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0157] In an exemplary embodiment, a controller is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0158] In an exemplary embodiment, as shown in FIG1 , the present application also provides a multi-cluster parallel battery cluster system, the system comprising: a plurality of battery clusters, first converters connected to the battery clusters one by one, and the controller in the above embodiment. The plurality of battery clusters are connected in parallel to the first DC bus; the first converter is connected in parallel to the second DC bus; the controller is connected to the battery clusters and the first converter, respectively.

[0159] Among them, as shown in Figure 1, the first converter 1-n is a bidirectional converter, which can convert electric energy between RACK and DC_BUS-2, thereby realizing the transfer of electric energy. The first converter can control the input / output voltage, current, and power, and the control accuracy is very high. In this application, the first converter 1-n is used to represent, and the same function can actually be realized by multiple converters. The controller can be a separate unit, or it can be integrated with other units with data processing capabilities such as energy management systems. In addition to collecting information such as voltage and current of each battery cluster and each first converter to realize the control function, the controller can also, in an exemplary embodiment, collect information such as voltage and current of each battery cluster and each first converter to realize the control function, and in the system, the battery is connected to the controller; the second converter is respectively connected to the battery, the first DC bus, the second DC bus and the controller; the third converter is respectively connected to the second DC bus and the controller, and the control function is realized by collecting information such as voltage and current of devices such as the battery, the second converter, the AC source and the third converter. Among them, the second converter can convert electric energy between the battery and DC_BUS-2, and can also convert the electric energy of DC_BUS-1 into DC_BUS-2. The second converter can control the input / output voltage, current, and power, and the control accuracy is very high. The third converter can convert the electric energy of the AC source into the electric energy of DC_BUS-2, which is used to replenish the balanced electric energy of each battery cluster, and can also be used to charge the battery. In one embodiment, as shown in Figure 1, the multi-cluster parallel battery cluster system also includes a plurality of switches (such as KM1, KM2 and KM3) arranged in each battery cluster, which are mainly used for balancing between clusters before the energy storage system needs to be started and connected, that is, when the voltage difference between any two battery clusters is greater than the first voltage threshold, the battery clusters are controlled to be connected. The current of this balancing is relatively large, and the balancing current is determined by the characteristics of the battery cluster and is uncontrollable.

[0160] The specific working process and beneficial effects of the multi-cluster parallel battery cluster system can refer to the description in the embodiment of the multi-cluster parallel battery cluster dynamic balancing control method, which will not be described in detail here.

[0161] In an exemplary embodiment, as shown in FIG1 , the present application further provides an energy storage system, including: a battery cluster system of multiple clusters connected in parallel as in the above embodiment. In addition, the energy storage system may also include an energy storage converter PCS, which is connected to the first DC bus DC_BUS-1 through switches KM4 and KM5.

[0162] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0163] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0164] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0165] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0166] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present application. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A dynamic balancing control method between multiple battery clusters connected in parallel, characterized in that: The method comprises: Obtain the voltage of each battery cluster; When the voltage difference between any two battery clusters is less than or equal to a first voltage threshold, determining an average voltage value of each battery cluster; If there is a target battery cluster, then according to the difference between the voltage of the target battery cluster and the voltage average value, the working state of the first converter connected to the target battery cluster is controlled to charge or discharge the target battery cluster until the difference between the voltage of any battery cluster and the voltage average value is less than or equal to a second voltage threshold; The difference between the voltage of the target battery cluster and the voltage average value is greater than the second voltage threshold, and the first voltage threshold is greater than the second voltage threshold.

2. The method for dynamic balancing control among multiple parallel battery clusters according to claim 1, characterized in that: The controlling the working state of the first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value comprises: If the voltages of the target battery clusters are all greater than the voltage average, the first converter connected to the target battery cluster is controlled to operate in a discharging state, and the second converter connected to the storage battery is controlled to operate in a charging state, so that the target battery cluster outputs electrical energy to the storage battery.

3. The method for dynamic balancing control among multiple parallel battery clusters according to claim 1, characterized in that: The controlling the working state of the first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value comprises: If the voltages of the target battery clusters are all lower than the voltage average, the first converter connected to the target battery cluster is controlled to operate in a charging state, and the second converter connected to the storage battery is controlled to operate in a discharging state, so that the target battery cluster receives the electric energy output by the storage battery; If the difference between the voltage of the target battery cluster and the voltage average value is still greater than the second voltage threshold, the third converter connected to the AC source is controlled to operate in a discharging state so that the target battery cluster receives the electric energy output by the AC source.

4. The method for dynamic balancing control among multiple parallel battery clusters according to claim 1, characterized in that: The controlling the working state of the first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value comprises: If the voltage of some of the target battery clusters is greater than the voltage average value, and the voltage of some of the target battery clusters is less than the voltage average value, control the first converter connected to the first battery cluster to operate in a discharging state, and control the first converter connected to the second battery cluster to operate in a charging state, so that the first battery cluster outputs electric energy to the second battery cluster; The first battery cluster is a target battery cluster whose voltage is greater than the voltage average value, and the second battery cluster is a target battery cluster whose voltage is less than the voltage average value.

5. The method for dynamic balancing control among multiple parallel battery clusters according to claim 4, characterized in that: After the step of controlling the first converter connected to the first battery cluster to operate in a discharging state and controlling the first converter connected to the second battery cluster to operate in a charging state, the method further includes: If the difference between the voltage of the target battery cluster and the voltage average value is still greater than the second voltage threshold, the working state of at least one of the second converter connected to the battery and the third converter connected to the AC source is controlled.

6. The method for dynamic balancing control between multiple parallel battery clusters according to any one of claims 1 to 5, characterized in that: The method further comprises: When the voltage difference between any two battery clusters is greater than the first voltage threshold, the battery clusters are controlled to be connected until the voltage difference between any two battery clusters is less than or equal to the first voltage threshold.

7. The method for dynamic balancing control among multiple parallel battery clusters according to claim 6, characterized in that: The controlling the battery clusters to be connected includes: The battery clusters are connected in order from the smallest voltage to the largest voltage of the battery clusters.

8. The method for dynamic balancing control among multiple parallel battery clusters according to claim 7, characterized in that: The connecting the battery clusters in order from the smallest to the largest voltage of the battery clusters comprises: Connect the first two battery clusters sorted in ascending order of voltage; The step of connecting the next battery cluster in ascending order of voltage when the current between the connected battery clusters is less than a preset current threshold is cyclically performed until all the battery clusters are connected.

9. The method for dynamic balancing control among multiple parallel battery clusters according to claim 6, characterized in that: The controlling the battery clusters to be connected includes: Connect the two battery clusters with the largest voltage difference; When the current between the connected battery clusters is less than the preset current threshold, the connection between the battery clusters is disconnected, and the process returns to the step of connecting the two battery clusters with the largest voltage difference.

10. The method for dynamic balancing control between multiple parallel battery clusters according to any one of claims 1 to 5, characterized in that: In the case where there are storage batteries and AC sources, after the step of controlling the working state of the first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value, the method further includes: If the remaining power of the storage battery is less than the preset power, the third converter connected to the AC source is controlled to operate in a discharging state, and the second converter connected to the storage battery is controlled to operate in a charging state.

11. The method for dynamic balancing control between multiple parallel battery clusters according to any one of claims 1 to 5, characterized in that: The controlling the working state of the first converter connected to the target battery cluster according to the difference between the voltage of the target battery cluster and the voltage average value comprises: If the energy storage system is in operation, the first converter connected to the first battery cluster is controlled to operate in a discharging state, and is connected to a first power transmission object according to a preset priority, and the converter connected to the first power transmission object is controlled to operate in a charging state, so that the first battery cluster outputs power to the first power transmission object; and / or, Controlling the first converter connected to the second battery cluster to operate in a charging state and accessing the second power transmission object according to a preset priority, and controlling the converter connected to the second power transmission object to operate in a discharging state, so that the second battery cluster receives the power output by the second power transmission object; Wherein, the first battery cluster is a target battery cluster whose voltage is greater than the voltage average value, and the second battery cluster is a target battery cluster whose voltage is less than the voltage average value; The first power transmission target includes one of a storage battery and the second battery cluster, the second power transmission target includes one of a storage battery, the first battery cluster and an AC source, and the priority of the storage battery is greater than the priority of the target battery cluster, and the priority of the target battery cluster is greater than the priority of the AC source.

12. A controller comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 11 are implemented.

13. A battery cluster system with multiple clusters connected in parallel, characterized in that: The system comprises: A plurality of battery clusters, wherein the plurality of battery clusters are connected in parallel to a first DC bus; First converters connected to the battery clusters one by one, respectively, and connected in parallel to a second DC bus; The controller as claimed in claim 12, wherein the controller is connected to the battery cluster and the first converter respectively.

14. The multi-cluster parallel battery cluster system according to claim 13, characterized in that: The system further comprises: A battery connected to the controller; A second converter, wherein the second converter is respectively connected to the battery, the first DC bus, the second DC bus and the controller; AC source; A third converter is connected to the second DC bus and the controller respectively.

15. An energy storage system, characterized in that: include: A multi-cluster parallel battery cluster system as claimed in any one of claims 13 to 14.

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