Multi-branch energy storage control system

Abstract

The present application discloses a multi-branch energy storage control system, including an EMS, at least one group of PCS, and at least two groups of BMS; the EMS collects and analyzes the status information of the PCS and BMS, determines the charging and discharging strategy according to the preset charging and discharging period, node charging and discharging power and voltage threshold, and allocates the rated charging and discharging power of each branch and the start and stop status instructions of each branch according to the strategy; the PCS and the EMS are connected, and the charging and discharging status of the battery packs of each branch is controlled according to the voltage threshold, rated charging and discharging power and status instructions issued by the EMS; when the voltage of at least one group of asymmetric branches under the second BMS exceeds the voltage threshold or the operating parameters are abnormal, the EMS controls the PCS to change the charging and discharging status of the corresponding asymmetric branch battery pack, and allocates the charging and discharging power of the remaining branches according to the number of asymmetric branches and the rated charging and discharging power. The present application sets the PCS and BMS as symmetric and asymmetric branches, which effectively improves the management efficiency and stability of the system.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of energy storage technology, and in particular to a multi-branch energy storage control system. Background Art

[0002] The energy storage system consists of an energy management system (EMS), several power control systems (PCS) and several battery management systems (BMS). It is an important measure for large factories or power plants to improve circuit stability. In order to compensate for power shortages when the power load is tight, the peak-to-valley method is used. For example, the battery pack is used to store energy during the valley period, and the energy is released during the peak period and incorporated into the power grid for power compensation.

[0003] In the related technology, the PCS and BMS of the energy storage system are matched one-to-one, which is characterized by the same number of PCS branches and BMS battery packs, and the battery capacity of the BMS is consistent. In the one-to-one matching control mode, each PCS needs to control the corresponding BMS separately, which is costly. The one-to-one symmetrical branch control mode will occupy the node resources of the PCS, and this control mode is not conducive to the reasonable allocation of battery pack resources. Summary of the invention

[0004] The present application provides a multi-branch energy storage control system to solve the problems of instability of the battery management system and unbalanced resource allocation in the power control system in the related art. The technical solution is as follows:

[0005] The system includes an energy management system EMS, at least one power control system PCS, and at least two battery management systems BMS; wherein the battery pack managed by the first battery BMS and the PCS are symmetrical branches, and the battery pack managed by the second BMS and the PCS are asymmetrical branches; the number of nodes in the symmetrical branch is the same as the number of battery packs; the number of nodes in the asymmetrical branch is different from the number of battery packs;

[0006] The EMS collects and analyzes the status information of the PCS and BMS, determines the current charge and discharge strategy according to the preset charge and discharge period, the charge and discharge power of a single branch and the voltage threshold, allocates the rated charge and discharge power of each branch according to the strategy and generates the start and stop status instructions of each branch to realize the charge and discharge of the battery pack;

[0007] The PCS is connected to the EMS and is used to control the charge and discharge status of the battery packs of each branch according to the voltage threshold, rated charge and discharge power and status instructions issued by the EMS;

[0008] When the voltage of at least one group of asymmetric branches under the second BMS exceeds the voltage threshold or the operating parameters are abnormal, the EMS controls the PCS to change the charge and discharge state of the corresponding asymmetric branch battery group, and allocates the charge and discharge power of the remaining branches according to the number of asymmetric branches and the rated charge and discharge power.

[0009] Specifically, the EMS is provided with a charging period and a discharging period; the charging period corresponds to the off-peak period of the power grid, and the battery pack corresponding to the BMS is charged by controlling the PCS; the discharging period corresponds to the peak period of the power grid, and the battery pack corresponding to the BMS is discharged by controlling the PCS.

[0010] Specifically, the EMS system queries the PCS branch operating parameters and determines the corresponding BMS battery pack number; the operating parameters include at least the PCS communication link, node power, start / stop status, and fault status; the EMS system determines the operating parameters of each battery pack by querying the BMS; the operating parameters include at least the BMS communication link, battery pack capacity, voltage, node number, and number of node branches.

[0011] Specifically, under normal charging and discharging conditions, the symmetrical node input / output power of the PCS to the first BMS is expressed as:

[0012] Pd=PP1 / Np

[0013] PP1 is the charge / discharge power allocated to the PCS by the EMS querying the battery pack capacity of the first BMS; Pd is the symmetric node input / output power; Np is the number of symmetric nodes and branches;

[0014] The asymmetric node input / output power of the PCS to the second BMS is expressed as:

[0015] Pi=(PP2 / Np)*Ni

[0016] Np is the number of asymmetric branches; i is the i-th asymmetric node of the second BMS; Ni is the number of branches under the i-th asymmetric node of the second BMS; PP2 is the charge / discharge power allocated to the PCS by the EMS querying the battery pack capacity of the second BMS.

[0017] Specifically, when the EMS detects that the operating parameters of at least one battery group in the first BMS are abnormal, or detects that the branch voltage of the symmetrical branch in the PCS exceeds the maximum charging threshold / is lower than the minimum discharging threshold; the node number of the target battery group is sent to the corresponding PCS; the PCS shuts down the charging / discharging behavior of the target branch according to the node number;

[0018] When the EMS detects that the operating parameters of at least one battery group in the second BMS are abnormal; the node number of the target battery group is sent to the corresponding PCS; the PCS shuts down the charging / discharging behavior of the target node;

[0019] When the EMS detects that the branch voltage of at least one battery group in the second BMS deviates from the normal voltage range; the number of branches in the target node that are in the normal voltage range is determined, and the charge / discharge power of the target node is determined based on the number of branches in the normal voltage range; expressed as:

[0020] Pi′=(PP2 / Np′)*Ni′

[0021] The power p of the Ni branches under the target node is expressed as:

[0022] p=Pi′ / Ni

[0023] Where Np' is the number of asymmetric branches in the normal voltage range; i is the i-th asymmetric node; Ni' is the number of branches in the normal voltage range under the i-th asymmetric node;

[0024] When there is at least one group of battery group branches whose voltage exceeds the maximum charging threshold value / is lower than the minimum discharging threshold value, the EMS controls the corresponding PCS to shut down the charging / discharging behavior of the target node.

[0025] Specifically, when the PCS and the BMS are in a one-to-one correspondence, the charge / discharge power allocated to the PCS is the rated charge / discharge power of the PCS;

[0026] When the PCS is connected to multiple BMSs, the PCS determines the charge / discharge power according to the number of connected BMSs and the battery capacity;

[0027] When the BMS is connected to a plurality of the PCSs, the PCS determines the charge / discharge power according to the number of connected nodes and the battery capacity.

[0028] Specifically, the battery pack capacities in the same BMS are the same; when the PCS is connected to multiple BMSs and at least one of the target nodes is shut down, the PCS will evenly distribute the power difference allocated to the target node before and after the shutdown to the branch nodes in other BMSs.

[0029] Specifically, the PCS stores a status detection bit and an abnormal status bit of the battery pack; the status detection bit is reset to 0 when the PCS changes the charging and discharging behavior;

[0030] In the charging state, when the EMS detects for the first time that the branch voltage under the target node exceeds the maximum charging threshold, it sends a confirmation instruction to the corresponding PCS; the PCS sets the state detection position of the target node to 1 according to the confirmation instruction, and shuts down the charging behavior for the target node;

[0031] In the discharge state, when the EMS detects for the first time that the branch voltage under the target node is lower than the minimum discharge threshold, the EMS sends the confirmation instruction to the corresponding PCS; the PCS sets the state detection position of the target node to 0 according to the confirmation instruction, and turns off the discharge behavior of the target node;

[0032] In the charging / discharging state, when the EMS detects that the operating parameters of the battery pack under the target node are abnormal, the PCS sets the abnormal state position of the target node to 1 and stops charging / discharging.

[0033] The beneficial effects brought about by the above technical solution include at least: by setting up a three-level management and control architecture of an energy management control system, a power control system and a battery management system, the power control system can achieve one-to-one or one-to-many control of the battery management system; and the battery management system adopts symmetrical branches and asymmetric structure connection, which can directly allow the power control system to achieve multi-battery pack control through a single node, reducing the complexity of battery pack control, and when the battery pack branch of the asymmetric branch exceeds the voltage threshold or the operating parameters are abnormal, the corresponding power control system can change the charging and discharging state of the corresponding node according to the detection results, and coordinately allocate the active power of the remaining branches to maintain the power supply balance of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 An architecture diagram of a multi-branch energy storage control system provided in an embodiment of the present application;

[0035] Figure 2 It is a schematic diagram of the connection between the battery management system and the power control system in the charging state using symmetrical branches and asymmetrical branches;

[0036] Figure 3 It is a connection diagram of symmetrical branches and asymmetrical branches between the battery management system and the power control system in the discharge state;

[0037] Figure 4 It is a schematic diagram of the structure before and after adjusting the node input power provided in an embodiment of the present application;

[0038] Figure 5 It is a flow chart of the algorithm for EMS controlling charging and discharging provided in this application. DETAILED DESCRIPTION

[0039] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0040] The term "multiple" as used herein refers to two or more than two. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the related objects are in an "or" relationship.

[0041] The original intention of establishing an energy management system is to use electricity reasonably and achieve peak load shaving and valley filling to balance the power load. The battery management system is equipped with several battery packs, which are charged during the peak phase of power and discharged during the valley phase of power and transmitted to the power grid. When the capacity of the battery assembly machine is large, it is necessary to set up power control for each battery pack to ensure power stability and the safety and stability of the battery pack.

[0042] In traditional power systems, the power control system and the battery management system are both one-to-one controlled, that is, a power control system manages all battery packs under a battery management system in the same way, and the battery capacity in a battery pack is consistent. The power control system can perform one-to-one power supply control on each battery pack in a targeted manner. When there are many battery packs, inconsistent battery pack capacities, and limited power control system interfaces, the power control system needs to control more battery packs to the maximum extent and achieve reasonable resource allocation.

[0043] Figure 1 This is the architecture diagram of the multi-branch energy storage control system provided in the embodiment of the present application. EMS management is responsible for overall power scheduling and allocation and charge and discharge state control. It is connected to multiple power control systems, and the power control systems PCS1, PCS2, PCS3, ... PCSn are set according to the power allocation. The rated charge and discharge power allocated to each PCS is determined by the number and capacity of the battery packs connected to it. Specifically, it can be divided into the following situations:

[0044] 1. When the power control system and the battery management system are in a one-to-one correspondence, the charge / discharge power allocated to the power control system is the rated charge / discharge power of the power control system; that is, one PCS corresponds to one BMS.

[0045] 2. When the power control system is connected to multiple battery management systems, the power control system determines the charge / discharge power according to the number of connected battery management systems and the battery capacity; that is, one PCS corresponds to multiple BMSs.

[0046] 3. When the battery management system is connected to multiple power control systems, the power control system determines the charge / discharge power according to the number of connected nodes and the battery capacity.

[0047] This situation is due to the fact that the number and capacity of battery packs may be different. This solution stipulates that all battery packs in the same battery management system have the same capacity, which can ensure that there will be no large voltage difference between battery packs, resulting in mutual charging and discharging. For battery packs with the same specifications and capacity, they can be managed together to reduce the complexity of the control system.

[0048] From the perspective of BMS, when the difference between battery packs with different installed capacities is large, the power values ​​between different PCSs also vary greatly. In order to balance the rated charge and discharge power values ​​between various power control systems, the BMS of large-capacity battery packs is split into multiple power PCSs. Figure 1 As shown in the figure, PCS1 controls BMS1 and BMS2, which is a one-to-many control. PCS2 controls BMS2 and BMS3, which is also a one-to-many control. However, BMS2 is controlled by both PCS1 and PCS2, that is, part of the battery pack under it is connected to the interface of PCS1, and the other part is connected to the interface of BMS2. Similarly, the control between PCSn and BMSm is a typical one-to-one control, which is stored in the cross control situation. After determining the number and capacity of battery packs connected to the PCS, the EMS can be used to distribute and control them according to the charging and discharging power values ​​that the PCS needs to provide under full load.

[0049] It should be noted that the one-to-many control in the above embodiment is only described by taking one-to-2 control as an example. In actual control, it can also be one-to-3 or more control modes, which is not limited in this embodiment.

[0050] The input or output connection between the PCS and the BMS is called a node, and the connection branch formed is called a symmetric branch or an asymmetric branch. The number of nodes in a symmetric branch is the same as the number of battery packs; the number of nodes in an asymmetric branch is different from the number of battery packs. Both the symmetry and asymmetry in this application are designed based on this node. The battery pack managed by the first battery management system and the power control system are symmetric branches, and the battery pack managed by the second battery management system and the power control system are asymmetric branches.

[0051] Figure 2 and Figure 3 The diagram shows the connection between the battery management system and the power control system using symmetrical branches and asymmetrical branches in the charging state and the discharging state.

[0052] When using symmetrical branches, one output of the PCS is a node, totaling P and nodes, and there is a one-to-one connection between the battery packs of the BMS. When using asymmetrical branches, at least one node of the PCS is connected to multiple battery packs. In this state, the PCS cannot achieve one-to-one control, but directly controls multiple battery packs through one node.

[0053] In order to enhance the safety of the EMS during the charging and discharging process, in addition to setting up control lines and communication lines between all PCSs, the EMS can query the power status of each PCS in real time. In addition, each BMS is also equipped with control lines and communication lines, which can query the working status of each battery pack in real time, or receive the operating status and operating parameters of each battery pack reported by the BMS. Each PCS can also query the operating status and operating parameters of the battery packs it manages in real time.

[0054] EMS is set with charging period and discharging period. The charging period corresponds to the off-peak period of the grid, and charging is performed by sending instructions to PCS. The discharging period corresponds to the peak period of the grid, and the discharge of each battery pack is controlled by the battery management system. EMS determines the operating status of the battery pack, the target battery management system to which the battery pack belongs, and the rated charge and discharge power of the corresponding PCS by querying the capacity and operating parameters of each battery pack. The operating parameters include at least one of the battery pack communication link, temperature, power, voltage, overcharge and over discharge, node number, and number of node branches.

[0055] Taking one-to-two control as an example, when the rated charge / discharge power has been determined for the PCS, the PCS allocates the rated charge / discharge power to the first battery management system and the second battery management system according to the battery capacity actually managed by the BMS (this power value is not less than the power of each BMS when working at full load during actual operation). The power values ​​are recorded as PP1 and PP2, and the sum of PP1 and PP2 is the rated charge / discharge power allocated to the power control system.

[0056] For the symmetrical branch of the first battery management system, under normal charging state, the output power of each symmetrical node of the power control system is expressed as:

[0057] Pd=PP1 / Np

[0058] Pd is the output power of each symmetrical node; Np is the number of symmetrical nodes, that is, the number of branches or battery packs included.

[0059] For the asymmetric branches of the second battery management system, since the number of branches contained in each node is different, the output power of each asymmetric node is expressed as:

[0060] Pi=(PP2 / Np)*Ni

[0061] Np is the number of asymmetric branches; i is the i-th asymmetric node of the second battery management system; Ni is the number of branches under the i-th asymmetric node of the second battery management system. Figure 4For example, the first output power corresponding to the first node is P1 = (PP2 / Np)*Nq. The nth output power corresponding to the nth node is expressed as Pn = (PP2 / Np)*N(px). It should be noted here that the power numbers allocated to each branch under the same node are the same.

[0062] The above description is based on charging. When the charging and discharging power values ​​are set to be the same, the discharging power is also calculated by referring to the above example formula. This application will not elaborate on this.

[0063] During normal charging and discharging, when the EMS detects that the operating parameters of at least one battery pack in the first battery management system are abnormal, or detects that the branch voltage of the symmetrical branch in the PCS exceeds the maximum charging threshold, or is lower than the minimum discharging threshold; it is necessary to send the node number of the target battery pack to the corresponding BMS, and specifically send instructions to the target PCS, which will query and confirm according to the node number of the target battery pack, and shut down the charging / discharging behavior of the target branch according to the node number. Under symmetrical branches, shutting down any branch will not affect the power input and output of other branches.

[0064] However, for the second battery management system, when there is abnormal behavior or the battery voltage reaches the threshold, the branch cannot be directly closed because the node is one-to-many controlled. Therefore, it needs to be controlled according to different situations. The details include the following:

[0065] 1. When the EMS detects that the operating parameters of at least one battery group in the second battery management system are abnormal.

[0066] EMS directly sends the node number of the target battery group to the corresponding PCS; PCS directly shuts down the charging / discharging behavior of the target node after querying BMS for confirmation. This process may be caused by a failure of the target battery group. If it is not shut down in time, it will affect the battery group of the entire BMS, and this operation will shut down all the battery groups that are charging and discharging under the same node.

[0067] 2. When the EMS detects that the branch voltage of at least one battery group in the second battery management system deviates from the normal voltage range.

[0068] The EMS first determines the number of branches in the target node that are within the normal voltage range, and then sends instructions to the PCS. The PCS determines the charge / discharge power of the target node based on the number of branches in the normal voltage range; it is expressed as:

[0069] Pi′=(PP2 / Np′)*Ni′

[0070] Np' is the number of asymmetric branches in the normal voltage range; i is the ith asymmetric node; Ni' is the number of branches in the normal voltage range under the ith asymmetric node. The purpose of this step is to take into account the fact that the charging and discharging voltage of the battery pack deviates from the normal value due to excessive charging and discharging, or the input and output voltage when the battery is fully charged and exhausted deviates from the normal range. At this time, the overall input and output of the node should be reduced. The idea is to calculate the average value based on the number of normal branches after excluding the input or output battery pack of the branch, and then calculate the node output based on the normal number of branches under the node, so that the power value can be appropriately reduced compared to the originally allocated power to extend the charging and discharging time. Correspondingly, the power p of the Ni branches under the target node and the power calculated by the actual PCS are expressed as:

[0071] p=Pi′ / Ni

[0072] PP2′=∑Pi=(PP2 / Np′)*Ni′

[0073] Ni is the number of branches under the i-th asymmetric node of the second battery management system (including the number of branches with normal voltage and branches offset from the normal voltage range); PP2' is the power value allocated to the second battery management system after power adjustment.

[0074] Since the inbound and outbound power of the EMS has been determined, large-scale voltage anomalies may affect the stability of the power system. In order to avoid voltage fluctuations, for the power cut by the second battery management system, the power control system will evenly distribute the power difference (PP2-PP2') allocated to the target node before and after shutdown to the branch nodes in other battery management systems.

[0075] like Figure 4 As shown in the figure, before adjustment, the power allocated to BMS1 and BMS2 is PP1 and PP2 respectively. After the voltage of the asymmetric branch shifts to the normal range, the power allocated to BMS2 becomes PP2', and the power allocated to PP1 becomes PP1+PP2-PP2'. That is, the power of the entire PCS remains unchanged.

[0076] On this basis, for asymmetric branches, when the battery pack voltage continues to increase or decrease until at least one group of battery pack branch voltage exceeds the maximum charging threshold or is lower than the minimum discharging threshold, the PCS corresponding to the EMS control must shut down the charging / discharging behavior of the target node to avoid battery damage caused by overcharging or over-discharging.

[0077] In some other implementations, in order to discharge or fully charge all battery packs at the same time as much as possible (under ideal conditions), a multi-level threshold is set for the battery pack, that is, when the voltage of the first group exceeds the normal range, the power difference is not directly loaded on other BMS, but multi-level threshold control is adopted. For other BMS mounted on the same PCS, the principle of step-by-step increase is followed, for example, first increase by 50%, and then increase by 25%, to speed up the charging process of other BMS, and try to fully charge the battery packs under the same PCS at the same time. The discharge principle is similar, and the battery packs of all BMS are controlled to be discharged as much as possible to facilitate system management.

[0078] During the battery charging and discharging process, the output voltage fluctuation of the battery pack is inevitable. For example, when the battery pack is fully charged and disconnected, before the discharge time is reached, its own power consumption causes the voltage to drop. In order to prevent the fully charged battery from being repeatedly charged due to the voltage drop, it is necessary to set a status detection bit (Dbo) for full charge detection. When the voltage of the battery pack drops, it is not charged repeatedly, but it is determined whether to charge based on Dbo. For discharge, a status detection bit (Dbi) is similarly set for low power detection. In addition, for battery packs that suddenly abnormally disconnect nodes, they may still charge or discharge when changing the charge and discharge status. If it is not marked, the entire battery pack will be damaged. Therefore, an abnormal status bit (Unl) is also set in this solution for abnormal judgment.

[0079] In the charging state, when the EMS detects for the first time that the branch voltage under the target node exceeds the maximum charging threshold, it sends a confirmation instruction to the corresponding PCS; the PCS sets the state detection position of the target node to 1 according to the confirmation instruction, and directly clears it to zero during the next charge and discharge.

[0080] In the discharge state, when the EMS detects for the first time that the branch voltage under the target node is lower than the minimum discharge threshold, it sends a confirmation instruction to the corresponding PCS; the PCS sets the state detection position of the target node to 0 according to the confirmation instruction, and directly clears it to zero during the next charge and discharge.

[0081] In the charge / discharge state, when the EMS detects that the operating parameters of the battery pack under the target node are abnormal, the PCS sets the abnormal state position of the target node to 1 and directly skips the subsequent charge and discharge process.

[0082] Figure 5It is an algorithm flow chart of EMS controlling charging and discharging provided in this application. EMS judges and changes the charging and discharging status of PCS and BMS according to the time period, and specifically obtains the operating parameters of the battery pack according to the communication between PCS and BMS. The operating parameters include at least one of the battery pack communication link, temperature, power, voltage, overcharge and over discharge, node number and number of node branches. When any system communication abnormality is detected, an interruption action is executed to avoid system failure and accidents. When it is determined that the communication is normal, for the charging status, it is determined whether to stop charging or continue charging according to the size of each group of battery branch voltages Uv and the maximum charging threshold Uh. In the discharge stage, it is determined whether to stop discharging or continue discharging according to the size of the battery group branch voltage Uv and the minimum discharge voltage threshold Ul. EMS controls the charging and discharging status of the entire power system according to time, achieves the purpose of peak shaving and valley filling, and provides a more stable power environment.

[0083] The preferred embodiments of the present invention are described above; it should be understood that the present invention is not limited to the above-mentioned specific embodiments, and the devices and structures not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can make many possible changes and modifications without departing from the technical solution of the present invention, or modify them into equivalent embodiments with equivalent changes, which does not affect the essential content of the present invention; therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A multi-branch energy storage control system, characterized in that: It includes an energy management system EMS, at least one power control system PCS, and at least two battery management systems BMS; wherein the battery pack managed by the first battery BMS and the PCS are symmetrical branches, and the battery pack managed by the second BMS and the PCS are asymmetrical branches; the number of nodes in the symmetrical branch is the same as the number of battery packs; the number of nodes in the asymmetrical branch is different from the number of battery packs; The EMS collects and analyzes the status information of the PCS and BMS, determines the current charge and discharge strategy according to the preset charge and discharge period, the charge and discharge power of a single branch and the voltage threshold, allocates the rated charge and discharge power of each branch according to the strategy and generates the start and stop status instructions of each branch to realize the charge and discharge of the battery pack; The PCS is connected to the EMS and is used to control the charge and discharge status of the battery packs of each branch according to the voltage threshold, rated charge and discharge power and status instructions issued by the EMS; When the voltage of at least one group of asymmetric branches under the second BMS exceeds the voltage threshold or the operating parameters are abnormal, the EMS controls the PCS to change the charge and discharge state of the corresponding asymmetric branch battery group, and allocates the charge and discharge power of the remaining branches according to the number of asymmetric branches and the rated charge and discharge power.

2. The multi-branch energy storage control system according to claim 1, characterized in that: The EMS is provided with a charging period and a discharging period; the charging period corresponds to the off-peak period of the power grid, and the battery pack corresponding to the BMS is charged by controlling the PCS; the discharging period corresponds to the peak period of the power grid, and the battery pack corresponding to the BMS is discharged by controlling the PCS.

3. The multi-branch energy storage control system according to claim 2, characterized in that: The EMS system queries the PCS branch operating parameters and determines the corresponding BMS battery pack number; the operating parameters include at least the PCS communication link, node power, start / stop status, and fault status; the EMS system determines the operating parameters of each battery pack by querying the BMS; the operating parameters include at least the BMS communication link, battery pack capacity, voltage, node number, and number of node branches.

4. The multi-branch energy storage control system according to claim 3, characterized in that: Under normal charging and discharging conditions, the symmetrical node input / output power of the PCS to the first BMS is expressed as: Pd=PP1 / Np PP1 is the charge / discharge power allocated to the PCS by the EMS querying the battery pack capacity of the first BMS; Pd is the symmetric node input / output power; Np is the number of symmetric nodes and branches; The asymmetric node input / output power of the PCS to the second BMS is expressed as: Pi=(PP2 / Np)*Ni Np is the number of asymmetric branches; i is the i-th asymmetric node of the second BMS; Ni is the number of branches under the i-th asymmetric node of the second BMS; PP2 is the charge / discharge power allocated to the PCS by the EMS querying the battery pack capacity of the second BMS.

5. The multi-branch energy storage control system according to claim 4, characterized in that: When the EMS detects that the operating parameters of at least one battery group in the first BMS are abnormal, or detects that the branch voltage of the symmetrical branch in the PCS exceeds the maximum charging threshold / is lower than the minimum discharging threshold; the node number of the target battery group is sent to the corresponding PCS; the PCS shuts down the charging / discharging behavior of the target branch according to the node number; When the EMS detects that the operating parameters of at least one battery group in the second BMS are abnormal; the node number of the target battery group is sent to the corresponding PCS; the PCS shuts down the charging / discharging behavior of the target node; When the EMS detects that the branch voltage of at least one battery group in the second BMS deviates from the normal voltage range; the number of branches in the target node that are in the normal voltage range is determined, and the charge / discharge power of the target node is determined based on the number of branches in the normal voltage range; expressed as: Pi′=(PP2 / Np′)*Ni′ The power p of the Ni branches under the target node is expressed as: p=Pi′ / Ni Where Np' is the number of asymmetric branches in the normal voltage range; i is the i-th asymmetric node; Ni' is the number of branches in the normal voltage range under the i-th asymmetric node; When there is at least one group of battery group branches whose voltage exceeds the maximum charging threshold value / is lower than the minimum discharging threshold value, the EMS controls the corresponding PCS to shut down the charging / discharging behavior of the target node.

6. The multi-branch energy storage control system according to claim 5, characterized in that: When the PCS and the BMS are in a one-to-one correspondence, the charge / discharge power allocated to the PCS is the rated charge / discharge power of the PCS; When the PCS is connected to multiple BMSs, the PCS determines the charge / discharge power according to the number of connected BMSs and the battery capacity; When the BMS is connected to a plurality of the PCSs, the PCS determines the charge / discharge power according to the number of connected nodes and the battery capacity.

7. The multi-branch energy storage control system according to claim 6, characterized in that: The battery packs in the same BMS have the same capacity; when the PCS is connected to multiple BMSs and at least one of the target nodes is shut down, the PCS will evenly distribute the power difference allocated to the target node before and after the shutdown to the branch nodes in other BMSs.

8. The multi-branch energy storage control system according to any one of claims 1 to 7, characterized in that: The PCS stores a status detection bit and an abnormal status bit of the battery pack; the status detection bit is reset to 0 when the PCS changes the charging and discharging behavior; In the charging state, when the EMS detects for the first time that the branch voltage under the target node exceeds the maximum charging threshold, it sends a confirmation instruction to the corresponding PCS; the PCS sets the state detection position of the target node to 1 according to the confirmation instruction, and shuts down the charging behavior for the target node; In the discharge state, when the EMS detects for the first time that the branch voltage under the target node is lower than the minimum discharge threshold, the EMS sends the confirmation instruction to the corresponding PCS; the PCS sets the state detection position of the target node to 0 according to the confirmation instruction, and turns off the discharge behavior of the target node; In the charging / discharging state, when the EMS detects that the operating parameters of the battery pack under the target node are abnormal, the PCS sets the abnormal state position of the target node to 1 and stops charging / discharging.

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