State of charge estimation method, controller, system, and storage medium

Abstract

The application discloses a state of charge estimation method, a controller, a system and a storage medium. The state of charge estimation method comprises the following steps: receiving an execution instruction, wherein the execution instruction comprises a shutdown instruction and a running instruction; if the execution instruction is the shutdown instruction, executing a first polling strategy based on a first state of charge value of a battery management system; and if the execution instruction is the running instruction, executing a second polling strategy based on a second state of charge value of the battery management system. According to different execution instructions and state of charge values of the battery management system, corresponding polling strategies are executed, so that the problem of inaccurate state of charge estimation of a large-capacity energy storage power station can be solved, and the safe and stable operation of the large-capacity energy storage power station is ensured.

Description

Technical Field

[0001] The present application relates to the field of electrochemical energy storage technology, and in particular to a state of charge estimation method, controller, system and storage medium. Background Art

[0002] Large-capacity energy storage systems can provide rapid active power support, enhance the grid's frequency and peak-shaving capabilities, and significantly improve the grid's ability to accommodate renewable energy. However, the batteries in these systems spend most of their time in a cycle of charge and discharge, making it difficult for the battery management system (BMS) managing these multiple batteries to accurately estimate the state of charge (SOC). However, accurate SOC estimation is crucial in the operation of large-capacity energy storage systems.

[0003] Currently, commercially available SOC estimation methods for battery management systems include the open-circuit voltage method, the ampere-hour integration method, and the Kalman filter method. The ampere-hour integration method is the most commonly used, but it suffers from cumulative errors. If not calibrated for an extended period, the SOC estimation accuracy will gradually deteriorate. Furthermore, in current large-capacity energy storage systems, SOC estimation is entirely performed by the battery management system. The energy management system (EMS) does not participate in SOC estimation, and the EMS lacks a functional module to improve the SOC estimation accuracy of the battery management system.

[0004] Therefore, inaccurate state of charge values ​​cannot effectively guide the operation of large-capacity energy storage power stations, reduce the service life of large-capacity energy storage power stations, and affect the safe and stable operation of large-capacity energy storage power stations. Summary of the Invention

[0005] The main purpose of this application is to provide a state of charge estimation method, controller, system and storage medium, aiming to solve the problem of inaccurate state of charge estimation in large-capacity energy storage power stations and ensure the safe and stable operation of large-capacity energy storage power stations.

[0006] To achieve the above objectives, the present application provides a state of charge estimation method, which is applied to a standard unit controller, wherein the standard unit controller controls at least two battery management systems. The state of charge estimation method includes the following steps:

[0007] receiving an execution instruction, wherein the execution instruction includes a stop instruction and a run instruction;

[0008] If the execution instruction is the shutdown instruction, executing a first polling strategy based on the first state of charge value of the battery management system;

[0009] If the execution instruction is the run instruction, a second polling strategy is executed based on the second state of charge value of the battery management system.

[0010] Optionally, the step of executing a first polling strategy based on the first state of charge value of the battery management system includes:

[0011] sorting the first state of charge values ​​to obtain a shutdown calibration queue of the battery management system;

[0012] Based on the shutdown calibration queue and a preset threshold, full charging and full discharging operations are performed on the battery management system.

[0013] Optionally, the step of performing full charge and full discharge operations on the battery management system based on the shutdown calibration queue and a preset threshold includes:

[0014] determining, in sequence, according to the shutdown calibration queue, whether the first state of charge value is greater than the threshold;

[0015] If the first state of charge value is greater than the threshold, fully charge the battery management system and fully discharge the battery;

[0016] If the state of charge value is less than or equal to the threshold, the battery management system is fully discharged and fully charged.

[0017] Optionally, the operation instruction includes a charging operation instruction and a discharging operation instruction. If the execution instruction is the operation instruction, the step of executing the second polling strategy based on the second state of charge value of the battery management system includes:

[0018] If the operation instruction is the charging operation instruction, performing a full charging operation on the battery management system based on a preset first power condition and the second state of charge value;

[0019] If the operation instruction is the discharge operation instruction, a full discharge operation is performed on the battery management system based on a preset second power condition and the second state of charge value.

[0020] Optionally, the step of performing a full charging operation on the battery management system based on a preset second sorting algorithm and the second state of charge value includes:

[0021] sorting the second state values ​​to obtain a charging calibration queue of the battery management system;

[0022] determining, based on the charging calibration queue, whether a first power of the battery management system meets the first power condition;

[0023] If the first power meets the first power condition, a full charging operation is performed on the battery management system.

[0024] Optionally, the step of performing a full discharge operation on the battery management system based on a preset third sorting algorithm and the second state of charge value includes:

[0025] sorting the second state values ​​to obtain a discharge calibration queue of the battery management system;

[0026] determining, based on the discharge calibration queue, whether the second power of the battery management system meets the second power condition;

[0027] If the second power meets the second power condition, a full discharge operation is performed on the battery management system.

[0028] Optionally, the state of charge estimation method further includes the following steps:

[0029] When executing the first polling strategy or the second polling strategy, obtaining a current event to determine whether an abnormality occurs in the current polling;

[0030] If an exception occurs in the current polling, the current polling is exited.

[0031] The present application also provides a standard unit controller, which includes:

[0032] An instruction receiving module is used to receive an execution instruction, wherein the execution instruction includes a stop instruction and a run instruction;

[0033] a first polling module, configured to execute a first polling strategy based on a first state of charge value of the battery management system if the execution instruction is the shutdown instruction;

[0034] The second polling module is configured to execute a second polling strategy based on a second state of charge value of the battery management system if the execution instruction is the run instruction.

[0035] The embodiment of the present application further provides a standard energy storage unit system, which includes a standard unit controller, a battery management system, an energy management system, and a communication network;

[0036] The energy management system is used to send execution instructions to the standard unit controller via the communication network;

[0037] The standard unit controller is configured to receive the execution instruction, wherein the execution instruction includes a shutdown instruction and a run instruction; if the execution instruction is the shutdown instruction, execute a first polling strategy based on the first state of charge value of the battery management system; if the execution instruction is the run instruction, execute a second polling strategy based on the second state of charge value of the battery management system;

[0038] The battery management system is configured to execute the first polling strategy or the second polling strategy.

[0039] An embodiment of the present application further provides a computer-readable storage medium, on which a state of charge estimation program is stored. When the state of charge estimation program is executed by a standard unit controller, the steps of the state of charge estimation method described above are implemented.

[0040] The state of charge estimation method, controller, system and storage medium proposed in the embodiment of the present application receive an execution instruction, and the execution instruction includes a shutdown instruction and a run instruction; if the execution instruction is the shutdown instruction, a first polling strategy is executed based on the first state of charge value of the battery management system; if the execution instruction is the run instruction, a second polling strategy is executed based on the second state of charge value of the battery management system. By executing corresponding polling strategies according to different execution instructions and the state of charge values ​​of the battery management system, the problem of inaccurate state of charge estimation of large-capacity energy storage power stations can be solved, and the safe and stable operation of large-capacity energy storage power stations can be ensured. Based on the scheme of the present application, starting from the law of low state of charge estimation accuracy of large-capacity energy storage systems in the power equipment industry, corresponding polling strategies are designed for different modes, and the effectiveness of the state of charge estimation method proposed in the present application is verified on the polling strategy. Finally, the accuracy of state of charge estimation by the method of the present application is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a functional module diagram of the energy storage standard unit system to which the standard unit controller of this application belongs;

[0042] Figure 2 A diagram of a standard energy storage unit system for the state of charge estimation method of this application;

[0043] Figure 3 This is a flow chart of a first exemplary embodiment of a method for estimating state of charge of the present application;

[0044] Figure 4 This is a flow chart of a second exemplary embodiment of a method for estimating state of charge of the present application;

[0045] Figure 5This is a flow chart of a third exemplary embodiment of a method for estimating state of charge of the present application;

[0046] Figure 6 This is a flow chart of a fourth exemplary embodiment of a method for estimating state of charge of the present application;

[0047] Figure 7 This is a flowchart of a fifth exemplary embodiment of a method for estimating state of charge of the present application;

[0048] Figure 8 This is a flow chart of a sixth exemplary embodiment of the state of charge estimation method of the present application;

[0049] Figure 9 Flowchart of abnormal exit from state of charge calibration of the state of charge estimation method of this application;

[0050] Figure 10 This is a flow chart of a state machine of a standard unit controller system of the state of charge estimation method of this application;

[0051] Figure 11 A flowchart of a seventh exemplary embodiment of the state of charge estimation method of the present application.

[0052] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0053] It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0054] The main solution of the embodiment of the present application is: receiving an execution instruction, the execution instruction includes a shutdown instruction and a run instruction; if the execution instruction is the shutdown instruction, then based on the first state of charge value of the battery management system, a first polling strategy is executed; if the execution instruction is the run instruction, then based on the second state of charge value of the battery management system, a second polling strategy is executed. According to different execution instructions and the state of charge values ​​of the battery management system, the corresponding polling strategy is executed, which can solve the problem of inaccurate state of charge estimation of large-capacity energy storage power stations and ensure the safe and stable operation of large-capacity energy storage power stations. Based on the solution of the present application, starting from the law of low state of charge estimation accuracy of large-capacity energy storage systems in the power equipment industry, corresponding polling strategies are designed for different modes, and the effectiveness of the state of charge estimation method proposed in the present application is verified on the polling strategy. Finally, the accuracy of the state of charge estimation by the method of the present application is significantly improved.

[0055] The embodiments of the present application take into account that in large-capacity energy storage systems, batteries are in a charge-discharge cycle for most of the time, and the state of charge (SOC) estimation accuracy of the battery management system (BMS) is generally unable to achieve accurate estimation. Accurate SOC estimation is of great significance in the use of large-capacity energy storage systems. Currently, commercial SOC estimation methods for battery management systems include: open circuit voltage method, ampere-hour integration method, Kalman filter method, etc. Among them, the ampere-hour integration method is the most commonly used, but the ampere-hour integration method has cumulative errors. If it is not calibrated for a long time, the accuracy of SOC estimation will gradually deteriorate. Currently, in large-capacity energy storage systems, SOC estimation is achieved by the battery management system. The energy management system (EMS) does not participate in SOC estimation, and the energy management system does not have relevant functional modules to improve the SOC estimation accuracy of the battery management system. Inaccurate SOC values ​​cannot effectively guide the operation of large-capacity energy storage power stations, shortening the service life of large-capacity energy storage power stations and affecting the safe and stable operation of large-capacity energy storage power stations.

[0056] Therefore, the embodiment of the present application, starting from the law of low accuracy of state of charge estimation in large-capacity energy storage systems in the power equipment industry, is based on the power control system of the standard unit controller (ESGU), integrating multiple battery management systems into a standard unit, and externally presenting the battery management system as a unified power conversion system. On the basis of completing the power dispatch instructions of the energy management system, etc., a timed polling strategy is adopted to control the battery pack in the standard unit controller so that it reaches the self-test conditions of the battery management system, and regularly creates conditions for the state of charge calibration of the battery management system. Corresponding polling strategies are designed for different modes, and the effectiveness of the state of charge estimation method proposed in this application is verified based on the polling strategy. Finally, the accuracy of the state of charge estimation by the method of this application is significantly improved.

[0057] Specifically, refer to Figure 1 , Figure 1 This is a functional module diagram of the energy storage standard unit system to which the standard unit controller of this application belongs. The standard unit controller can be a standard unit controller independent of the energy storage standard unit system, capable of performing state of charge value calculation and polling strategy, and can be hosted on the energy storage standard unit system in the form of hardware or software.

[0058] In this embodiment, the energy storage standard unit system to which the standard unit controller belongs includes at least a standard unit controller 110, a battery management system 120, an energy management system 130, and a communication network 140;

[0059] The energy management system 130 is used to send execution instructions to the standard unit controller 110 through the communication network 140;

[0060] The standard unit controller 110 is configured to receive the execution instruction, wherein the execution instruction includes a shutdown instruction and a run instruction; if the execution instruction is the shutdown instruction, execute a first polling strategy based on the first state of charge value of the battery management system 120; if the execution instruction is the run instruction, execute a second polling strategy based on the second state of charge value of the battery management system 120;

[0061] The battery management system 120 is configured to execute the first polling strategy or the second polling strategy.

[0062] Further, refer to Figure 2 , Figure 2 This is a system diagram of a standard energy storage unit for the state of charge estimation method of the present application, including an energy management system (EMS), a coordination controller (CCU), a human-machine interface (HMI), a power converter (PCS), a battery management system (BMS), and a standard unit controller (ESGU), wherein the energy management system (EMS) includes one or more, the standard unit controller (ESGU) power control system includes one or more, and each standard unit controller (ESGU) power control system and one or more battery management systems and power converters corresponding to the battery management systems form a corresponding standard unit.

[0063] Based on the Standard Generator Set Controller (ESGU) power control system, multiple battery management systems are integrated into a single standard generator set, presenting the appearance of a unified power conversion system. Based on the energy management system's power dispatch instructions, a timed polling strategy is used to control the battery pack within the standard generator set controller, ensuring that it meets the battery management system's self-test conditions. This creates conditions for regular state-of-charge calibration of the battery management system, improving the accuracy of state-of-charge estimation, and thereby extending the service life of large-capacity energy storage power stations and ensuring their safe and stable operation.

[0064] The standard unit controller communicates with the energy management system via IEC61850 MMS (MMS) mapping, transmitting all information within the energy storage unit and providing command control for the energy management system. The standard unit controller communicates with the coordination controller via the EtherCAT protocol to perform transient control of the energy storage unit. The standard unit controller integrates multiple battery management systems into a single standard unit, presenting the standard unit as a unified power conversion system. Based on the energy management system's power dispatch instructions, a timed polling strategy is used to control the battery pack within the standard unit controller. Specifically, when the standard unit controller receives an execution command, it sets a timed polling strategy corresponding to the shutdown and operating modes to ensure the battery management system self-test conditions. This also allows for regular state-of-charge calibration of the battery management system, improving the accuracy of state-of-charge estimation. This, in turn, extends the service life of the large-capacity energy storage power station and ensures its safe and stable operation.

[0065] This embodiment specifically receives an execution instruction through the above scheme, and the execution instruction includes a shutdown instruction and a run instruction; if the execution instruction is the shutdown instruction, then based on the first state of charge value of the battery management system, a first polling strategy is executed; if the execution instruction is the run instruction, then based on the second state of charge value of the battery management system, a second polling strategy is executed. According to different execution instructions and the state of charge values ​​of the battery management system, the corresponding polling strategy is executed, which can solve the problem of inaccurate state of charge estimation of large-capacity energy storage power stations and ensure the safe and stable operation of large-capacity energy storage power stations. Based on the scheme of this application, starting from the law of low state of charge estimation accuracy of large-capacity energy storage systems in the power equipment industry, corresponding polling strategies are designed for different modes, and the effectiveness of the state of charge estimation method proposed in this application is verified on the polling strategy. Finally, the accuracy of state of charge estimation by the method of this application is significantly improved.

[0066] Based on the above energy storage standard unit system architecture but not limited to the above architecture, an embodiment of the method of this application is proposed.

[0067] Reference Figure 3 , Figure 3 This is a flow chart of a first exemplary embodiment of the state of charge estimation method of the present application. The state of charge estimation method is applied to a standard unit controller, which controls at least two battery management systems. The state of charge estimation method includes:

[0068] Step S310, receiving an execution instruction, wherein the execution instruction includes a shutdown instruction and a run instruction;

[0069] Large-capacity energy storage systems can provide rapid active power support, enhance the grid's frequency and peak-shaving capabilities, and significantly improve the grid's ability to accommodate renewable energy. However, the batteries in large-capacity energy storage systems spend the vast majority of their time in a charge-discharge cycle, making it difficult for the battery management system (BMS) managing multiple batteries to accurately estimate the state of charge (SOC). Against this backdrop, the present invention proposes a method for improving the accuracy of SOC estimation for a standard unit energy storage system.

[0070] Specifically, the execution instruction is used by the standard generator set controller (ESGU) power control system to enter a corresponding mode and execute a corresponding polling strategy according to the execution instruction. The execution instruction includes but is not limited to a shutdown instruction and an operation instruction. The standard generator set controller (ESGU) power control system receives the energy management system (EMS) execution instruction through the standard generator set controller (ESGU). If the execution instruction is a shutdown instruction, the system enters the shutdown mode and executes the first polling strategy; if the execution instruction is a run instruction, the system enters the run mode and executes the second polling strategy.

[0071] In addition, other instructions are instructions other than the shutdown instruction and the operation instruction. When the execution instruction received by the standard unit controller is other instructions, the first polling strategy or the second polling strategy is not executed, that is, the state of charge calibration is not performed.

[0072] Step S320: If the execution instruction is the shutdown instruction, executing a first polling strategy based on the first state of charge value of the battery management system;

[0073] Specifically, the first polling strategy is used in shutdown mode. The standard unit controller obtains the state of charge value of the corresponding battery management system and fully charges and discharges each battery management system according to the state of charge value and the current available power. When the standard unit controller receives a shutdown command sent by the energy management system through the communication network (IEC61850 mapping manufacturing message MMS communication), it enters the shutdown mode according to the shutdown command and executes the first timed polling strategy to enable it to meet the self-test conditions of the battery management system, regularly create conditions for the state of charge calibration of the battery management system, and improve the accuracy of the state of charge estimation. It can improve the accuracy of the state of charge estimation of the energy storage system, thereby increasing the service life of large-capacity energy storage power stations and ensuring the safe and stable operation of large-capacity energy storage power stations.

[0074] Step S330: If the execution instruction is the run instruction, a second polling strategy is executed based on the second state of charge value of the battery management system.

[0075] Specifically, the operation mode includes a charging operation mode and a discharging operation mode, the second polling strategy is used in the charging operation mode or the discharging operation mode, the standard unit controller acquires the state of charge value of the corresponding battery management system, and full charging or full discharging is performed on each battery management system according to the state of charge value and the current available power. When the standard unit controller receives the charging operation instruction or the discharging operation instruction sent by the energy management system through the communication network (IEC61850 mapping manufacturing message MMS communication), the operation mode is entered according to the operation instruction, the second timing polling strategy is executed, the battery management system self-checking condition is reached, the state of charge calibration condition of the battery management system is created regularly, and the state of charge estimation accuracy is improved. The state of charge estimation accuracy of the energy storage system can be improved, and then the service life of the large-capacity energy storage power station is improved, and the safe and stable operation of the large-capacity energy storage power station is ensured.

[0076] In the embodiment, the execution instruction includes a shutdown instruction and an operation instruction. If the execution instruction is the shutdown instruction, the first polling strategy is executed based on the first state of charge value of the battery management system. If the execution instruction is the operation instruction, the second polling strategy is executed based on the second state of charge value of the battery management system. According to different execution instructions and state of charge values of the battery management system, corresponding polling strategies are executed, the problem of inaccurate state of charge estimation of the large-capacity energy storage power station is solved, and the safe and stable operation of the large-capacity energy storage power station is ensured.

[0077] Referring to Figure 4 , Figure 4 FIG. 1 is a flowchart of a second exemplary embodiment of a state of charge estimation method according to the present application. Based on the above-mentioned Figure 3 In the embodiment shown in FIG. 1, step S320, the first polling strategy is executed based on the first state of charge value of the battery management system, including:

[0078] Step S410, the first state of charge value is sorted to obtain a shutdown calibration queue of the battery management system.

[0079] Specifically, the first state of charge value is the state of charge value of the currently online battery management system in the shutdown mode. In the shutdown mode, the first state of charge value can be sorted by a first sorting algorithm, that is, the battery management system is sorted according to the state of charge value corresponding to the currently online battery management system to obtain a shutdown calibration queue. In this way, according to the order in the shutdown calibration queue, the battery management system that needs to be operated can be obtained.

[0080] Among them, the first sorting algorithm can sort the state of charge values ​​from large to small, or it can sort the state of charge values ​​from small to large, including but not limited to bubble sort, selection sort, shell sort, merge sort, quick sort, heap sort, counting sort, bucket sort, and radix sort. The embodiment of the present application prefers the bubble sort algorithm, and other sorting algorithms can also be used in other embodiments.

[0081] Step S420: Based on the shutdown calibration queue and a preset threshold, the battery management system is fully charged and fully discharged.

[0082] Specifically, the shutdown calibration queue is used to determine whether the state of charge value of each battery management system meets the threshold value according to its order, so as to perform the corresponding full charge and full discharge operations. The threshold is used to determine whether the state of charge value of the currently online battery management system meets the threshold range, so as to perform the corresponding full charge and full discharge operations. By sorting the state of charge values ​​corresponding to the currently online battery management system from large to small through the first sorting algorithm, the shutdown calibration queue of the currently online battery management system based on the size of the state of charge value can be obtained. In this way, the standard unit controller (ESGU) can determine the state of charge value of each battery management system in the shutdown calibration queue.

[0083] Furthermore, step S420, based on the shutdown calibration queue and a preset threshold, performs full charge and full discharge operations on the battery management system, including:

[0084] Step S421, determining in sequence whether the first state of charge value is greater than the threshold value according to the shutdown calibration queue;

[0085] Specifically, the SOC values ​​of each battery management system are sorted according to a sorting algorithm to generate a shutdown calibration queue. This means that, based on the SOC values, the system sequentially determines whether they are greater than a preset threshold, thereby performing full charge and discharge operations. The preset threshold is set based on actual conditions; in this embodiment, a threshold of 50% is used as an example.

[0086] Step S422: If the first state of charge value is greater than the threshold, fully charge the battery management system and fully discharge the battery;

[0087] Specifically, if the state of charge value of the currently online battery management system is greater than 50%, the battery pack corresponding to the battery management system is fully charged, then left to stand for several hours, and then the battery pack is fully discharged. After standing for several hours, the battery management system is deleted from the power outage calibration queue, and step S421 is executed for the next currently online battery management system, that is, the state of charge calibration of the next battery management system is performed.

[0088] Step S423: If the state of charge value is less than or equal to the threshold, the battery management system is fully discharged and fully charged.

[0089] Specifically, if the state of charge value of the currently online battery management system is less than or equal to 50%, the battery pack corresponding to the battery management system is fully discharged, then left to stand for several hours, and then the battery pack is fully charged. After standing for several hours, the battery management system is deleted from the power outage calibration queue, and step S421 is executed for the next currently online battery management system, that is, the state of charge calibration of the next battery management system is performed.

[0090] This embodiment, through the above-described scheme, specifically sorts the first SOC values ​​to obtain a shutdown calibration queue for the battery management system. Based on the shutdown calibration queue, it sequentially determines whether the first SOC values ​​are greater than a threshold. If the first SOC value is greater than the threshold, the battery management system is fully charged and fully discharged. If the SOC value is less than or equal to the threshold, the battery management system is fully discharged and fully charged. By sorting the SOC values ​​of each battery management system to generate a shutdown calibration queue and determining whether the SOC value meets the threshold range, the efficiency of SOC estimation can be improved.

[0091] Reference Figure 5 , Figure 5 This is a flow chart of the third exemplary embodiment of the charge state estimation method of this application. Figure 3 In the embodiment shown, in step S330, if the execution instruction is the run instruction, executing a second polling strategy based on the second state of charge value of the battery management system includes:

[0092] Step S510: If the operation instruction is the charging operation instruction, performing a full charging operation on the battery management system based on a preset first power condition and the second state of charge value;

[0093] Specifically, the first power condition is used by the ESGU to determine whether the currently online battery management system can perform a full charge operation in charging mode. The second state of charge value is used to sort the battery management systems. In this way, the ESGU comprehensively determines the current available power of each sorted battery management system based on the first power condition. If the available power of the battery management system meets the first power condition, a full charge operation is performed.

[0094] Step S520: If the operation instruction is the discharge operation instruction, a full discharge operation is performed on the battery management system based on a preset second power condition and the second state of charge value.

[0095] Specifically, the second power condition is used by the ESGU to determine whether the currently online battery management system can perform a full charge operation in the discharge mode. The second state of charge value is used to sort the battery management systems. The ESGU then comprehensively determines the currently available power of each sorted battery management system based on the second power condition. If the available power of the battery management system meets the second power condition, the full discharge operation is performed.

[0096] This embodiment utilizes the above-described solution. Specifically, if the operating instruction is the charging operating instruction, a full charge operation is performed on the battery management system based on a preset first power condition and the second state of charge value; and if the operating instruction is the discharging operating instruction, a full discharge operation is performed on the battery management system based on a preset second power condition and the second state of charge value. By setting power conditions to determine whether the current available power in the charging operating mode or the discharging operating mode can be used to perform state of charge calibration, the problem of inaccurate state of charge estimation in the charging and discharging modes of large-capacity energy storage power stations can be resolved, thereby ensuring the safe and stable operation of large-capacity energy storage power stations.

[0097] Reference Figure 6 , Figure 6 This is a flow chart of a fourth exemplary embodiment of the state of charge estimation method of this application, based on the above Figure 5 In the illustrated embodiment, step S510, based on a preset second sorting algorithm and the second state of charge value, performs a full charging operation on the battery management system, including:

[0098] Step S610, sorting the second state values ​​to obtain a charging calibration queue of the battery management system;

[0099] Specifically, in the charging operation mode, the second state of charge values ​​can be sorted using a second sorting algorithm. That is, the battery management systems are sorted based on the state of charge values ​​corresponding to the currently online battery management systems to obtain a charging calibration queue. In this way, based on the order in the charging calibration queue and the first power condition, it is determined whether each battery management system has executed a full charging operation.

[0100] Among them, the second sorting algorithm is used to sort the state of charge values ​​from large to small, including but not limited to bubble sort, selection sort, shell sort, merge sort, quick sort, heap sort, counting sort, bucket sort, and radix sort. The embodiment of the present application prefers the bubble sort algorithm, and other sorting algorithms may also be used in other embodiments.

[0101] Step S620, judging whether the first power of the battery management system meets the first power condition based on the charging calibration queue;

[0102] Specifically, the first power is the current available power of each battery management system currently online, and the first power condition is the instruction power carried by the execution instruction, which is used to judge whether the current available power of each battery management system currently online meets the instruction power carried by the execution instruction. In this embodiment, based on the state of charge values of each battery management system, the current available power of the battery management system is sequentially judged whether it meets the instruction power carried by the charging operation instruction from large to small. If it meets the instruction power, the battery management system is fully charged.

[0103] Step S630, if the first power meets the first power condition, performing full charging operation on the battery management system.

[0104] Specifically, if it is judged that the current available power of the battery management system meets the instruction power carried by the charging operation instruction, the battery management system is fully charged, that is, the battery management system with the largest state of charge value in the current charging calibration queue is fully charged. After several hours of standing, the battery management system is deleted from the charging calibration queue, and steps S610 to S630 are executed again to estimate the state of charge of the next battery management system.

[0105] The above scheme is used to sort the second state values to obtain the charging calibration queue of the battery management system, judge whether the first power of the battery management system meets the first power condition based on the charging calibration queue, and perform full charging operation on the battery management system if the first power meets the first power condition. By judging whether the current available power of the battery management system in the charging operation mode meets the power condition, the full charging operation of the battery management system is performed, which can solve the problem of inaccurate state of charge estimation in the charging operation mode of the large-capacity energy storage power station and ensure the safe and stable operation of the large-capacity energy storage power station.

[0106] Reference Figure 7 , Figure 7 The flowchart of the fifth exemplary embodiment of the state of charge estimation method is shown in the above Figure 5 Based on the above

[0107] Step S710, sorting the second state values to obtain the discharge calibration queue of the battery management system;

[0108] Specifically, in the discharge operation mode, the second state of charge values ​​can be sorted using a third sorting algorithm. That is, the battery management systems are sorted based on the state of charge values ​​corresponding to the currently online battery management systems to obtain a discharge calibration queue. In this way, the battery management system that needs to be operated can be obtained based on the order in the discharge calibration queue.

[0109] Among them, the third sorting algorithm is used to sort the state of charge values ​​from small to large, including but not limited to bubble sort, selection sort, shell sort, merge sort, quick sort, heap sort, counting sort, bucket sort, and radix sort. The embodiment of the present application prefers the bubble sort algorithm, and other sorting algorithms may also be used in other embodiments.

[0110] Step S720: determining whether the second power of the battery management system meets the second power condition based on the discharge calibration queue;

[0111] Specifically, the second power is the currently available power of each currently online battery management system, and the second power condition is the command power carried by the execution instruction, which is used to determine whether the currently available power of each currently online battery management system meets the command power carried by the execution instruction. In this embodiment, based on the state of charge value of each battery management system, from small to large, the current available power of the battery management system is determined to determine whether it meets the command power carried by the discharge operation instruction. If it meets the command power, the battery management system is fully discharged.

[0112] Step S730: If the second power meets the second power condition, a full discharge operation is performed on the battery management system.

[0113] Specifically, if it is determined that the current available power of the battery management system meets the command power carried by the discharge operation instruction, the battery management system is fully discharged, that is, the battery management system with the largest state of charge value in the current discharge calibration queue is fully discharged. After standing for several hours, the battery management system is deleted from the discharge calibration queue, and steps S710 to S730 are executed to estimate the state of charge of the next battery management system.

[0114] This embodiment utilizes the above-described solution to obtain a discharge calibration queue for the battery management system by specifically sorting the second state values. Based on the discharge calibration queue, a determination is made as to whether the second power of the battery management system meets the second power condition. If the second power meets the second power condition, a full discharge operation is performed on the battery management system. By determining whether the currently available power of the battery management system meets the power condition during the discharge operation mode and performing the full discharge operation on the battery management system, the problem of inaccurate state of charge estimation during the discharge operation mode of large-capacity energy storage power stations can be resolved, thereby ensuring the safe and stable operation of large-capacity energy storage power stations.

[0115] Reference Figure 8 , Figure 8 This is a flow chart of the sixth exemplary embodiment of the state of charge estimation method of this application, based on the above Figure 3 In the embodiment shown, the state of charge estimation method further includes the following steps:

[0116] Step S810: When executing the first polling strategy or the second polling strategy, obtain a current event to determine whether an abnormality occurs in the current polling;

[0117] Specifically, the current event is used to interrupt and exit the first polling strategy or the second polling strategy. The current event includes but is not limited to: receiving one or more frequency modulation instructions, source grid load storage interaction events, and emergency events. Figure 9 , Figure 9 Flowchart for exiting abnormal SOC calibration in the SOC estimation method of the present application. By performing SOC calibration, the current event is acquired in real time or periodically to determine whether SOC calibration has experienced an abnormality. First, a determination is made as to whether one or more frequency modulation instructions have been received. If so, SOC calibration is exited. Otherwise, a determination is made as to whether a source-grid-charge-storage interaction event has occurred. If so, SOC calibration is exited. Otherwise, a determination is made as to whether an emergency event has occurred. If so, SOC calibration is exited. Otherwise, SOC calibration is continued.

[0118] Step S820: If an exception occurs in the current polling, exit the current polling.

[0119] Specifically, refer to Figure 10 , Figure 10This is a flow chart of the standard unit controller system state machine of the state of charge estimation method of this application. As shown in the figure, the standard unit controller system state machine mainly includes system self-test, initialization, shutdown mode, standby mode, operation mode, alarm mode, and fault mode. Among them, the standard unit controller provides a calibration state of charge function module for the battery management system, which is located in the shutdown mode and operation mode. When an alarm fault event occurs, the system state machine enters the corresponding state. If the state of charge calibration procedure is currently in progress, the calibration procedure will be interrupted and the system will exit the state of charge calibration procedure.

[0120] This embodiment utilizes the above solution to obtain the current event during execution of the first or second polling strategy to determine whether the current polling is abnormal; if the current polling is abnormal, the current polling is exited. By dynamically determining whether the current event is abnormal, abnormalities can be discovered in a timely manner, ensuring the safety and stability of large-capacity energy storage power station operations.

[0121] Specifically, refer to Figure 11 , Figure 11 The flowchart of the seventh exemplary embodiment of the state of charge estimation method of the present application is as follows. Figure 3 In the embodiment shown, the power control system of the standard generator set controller (ESGU) receives execution commands from the energy management system (EMS) and enters different modes according to the operation instructions, wherein the execution commands include shutdown commands and operation instructions.

[0122] If the execution command is a shutdown command, the state of charge (SOC) calibration in shutdown mode is entered: first, the standard unit controller (ESGU) power control system calculates the current online battery management system (BMS) in the standard unit, and then uses the bubble sorting algorithm to sort the state of charge (SOC) values ​​of each battery management system (BMS) to obtain a shutdown calibration queue; based on the shutdown calibration queue, it is determined whether the state of charge value corresponding to the battery management system is greater than 50%; if the state of charge value of the battery management system is greater than 50%, the battery pack of the battery management system is fully charged. Charge the battery pack of the battery management system, then let it stand for several hours, then fully discharge the battery pack of the battery management system, then let it stand for several hours, then delete the battery management system from the shutdown calibration queue, and determine whether the state of charge value of the next battery management system is greater than 50%; if the state of charge value of the battery management system is less than or equal to 50%, then fully discharge the battery pack of the battery management system, then let it stand for several hours, then fully charge the battery pack of the battery management system, then let it stand for several hours, then delete the battery management system from the shutdown calibration queue, and determine whether the state of charge value of the next battery management system is greater than 50%;

[0123] If the execution command is a run instruction, the state of charge (SOC) calibration in the run mode is entered: first, the standard unit controller (ESGU) power control system calculates the currently online battery management system (BMS) in the standard unit; if the current operation is charging, the state of charge values ​​of each currently online battery management system are sorted by bubble sorting to obtain a charging operation queue, and then based on the order of the charging operation queue and the command power carried by the run instruction, the current power of the battery management system with the largest state of charge value is comprehensively judged. If it meets the current available power and the command power, the battery management system is fully charged, then left to stand for several hours, and then deleted from the charging operation queue; if the current operation is discharging, the state of charge values ​​of each currently online battery management system are sorted by bubble sorting to obtain a discharging operation queue, and then based on the order of the discharging operation queue and the command power carried by the run instruction, the current power of the battery management system with the smallest state of charge value is comprehensively judged. If it meets the current available power and the command power, the battery management system is fully discharged, then left to stand for several hours, and then deleted from the discharging operation queue;

[0124] If the execution command is other instructions, the state of charge calibration will not be performed.

[0125] This embodiment integrates multiple battery management systems into a single standard unit through a power control system based on a standard unit controller, presenting the system as a unified power conversion system. Based on the energy management system's power dispatch instructions, a timed polling strategy is used to control the battery pack within the standard unit controller, ensuring that it meets the battery management system's self-test conditions. This creates conditions for regular state-of-charge (SOC) calibration, improves SOC estimation accuracy, and ultimately extends the service life of the large-capacity energy storage power station, ensuring its safe and stable operation.

[0126] In addition, the embodiment of the present application further provides a standard unit controller, which includes:

[0127] An instruction receiving module is used to receive an execution instruction, wherein the execution instruction includes a stop instruction and a run instruction;

[0128] a first polling module, configured to execute a first polling strategy based on a first state of charge value of the battery management system if the execution instruction is the shutdown instruction;

[0129] The second polling module is configured to execute a second polling strategy based on a second state of charge value of the battery management system if the execution instruction is the run instruction.

[0130] For the principle and implementation process of realizing the state of charge estimation in this embodiment, please refer to the above embodiments and will not be repeated here.

[0131] In addition, the embodiment of the present application also proposes a standard energy storage unit system, which includes a standard unit controller, a battery management system, an energy management system, and a communication network;

[0132] The energy management system is used to send execution instructions to the standard unit controller via the communication network;

[0133] The standard unit controller is configured to receive the execution instruction, wherein the execution instruction includes a shutdown instruction and a run instruction; if the execution instruction is the shutdown instruction, execute a first polling strategy based on the first state of charge value of the battery management system; if the execution instruction is the run instruction, execute a second polling strategy based on the second state of charge value of the battery management system;

[0134] The battery management system is configured to execute the first polling strategy or the second polling strategy.

[0135] Since the energy storage standard unit system adopts all the technical solutions of all the aforementioned embodiments when it is implemented, it has at least all the beneficial effects brought about by all the technical solutions of all the aforementioned embodiments, which will not be described one by one here.

[0136] In addition, an embodiment of the present application further provides a computer-readable storage medium, on which a state of charge estimation program is stored. When the state of charge estimation program is executed by a standard unit controller, the steps of the state of charge estimation method described above are implemented.

[0137] Since this state of charge estimation program adopts all the technical solutions of all the aforementioned embodiments when executed by the standard unit controller, it has at least all the beneficial effects brought by all the technical solutions of all the aforementioned embodiments, which will not be described one by one here.

[0138] Compared with the prior art, the state of charge estimation method, controller, system and storage medium proposed in the embodiment of the present application receive an execution instruction, and the execution instruction includes a shutdown instruction and a run instruction; if the execution instruction is the shutdown instruction, a first polling strategy is executed based on the first state of charge value of the battery management system; if the execution instruction is the run instruction, a second polling strategy is executed based on the second state of charge value of the battery management system. By executing corresponding polling strategies according to different execution instructions and the state of charge values ​​of the battery management system, the problem of inaccurate state of charge estimation of large-capacity energy storage power stations can be solved, and the safe and stable operation of large-capacity energy storage power stations can be ensured. Based on the scheme of the present application, starting from the law of low state of charge estimation accuracy of large-capacity energy storage systems in the power equipment industry, corresponding polling strategies are designed for different modes, and the effectiveness of the state of charge estimation method proposed in the present application is verified on the polling strategy. Finally, the accuracy of state of charge estimation by the method of the present application is significantly improved.

[0139] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or system. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or system comprising the element.

[0140] The serial numbers of the above embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0141] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course, by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as above, and includes a number of instructions for enabling a standard energy storage unit system to execute the method of each embodiment of the present application.

[0142] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for estimating state of charge, characterized in that: The state of charge estimation method is applied to a standard unit controller, which controls at least two battery management systems. The state of charge estimation method includes the following steps: receiving an execution instruction, wherein the execution instruction includes a stop instruction and a run instruction; If the execution instruction is the shutdown instruction, executing a first polling strategy based on the first state of charge value of the battery management system; If the execution instruction is the run instruction, executing a second polling strategy based on the second state of charge value of the battery management system; The step of executing a first polling strategy based on the first state of charge value of the battery management system includes: sorting the first state of charge values ​​to obtain a shutdown calibration queue of the battery management system; Based on the shutdown calibration queue and a preset threshold, full charging and full discharging operations are performed on the battery management system.

2. The method for estimating state of charge according to claim 1, wherein: The step of performing full charge and full discharge operations on the battery management system based on the shutdown calibration queue and the preset threshold comprises: determining, in sequence, according to the shutdown calibration queue, whether the first state of charge value is greater than the threshold; If the first state of charge value is greater than the threshold, fully charge the battery management system and fully discharge the battery; If the state of charge value is less than or equal to the threshold, the battery management system is fully discharged and fully charged.

3. The method for estimating state of charge according to claim 1, wherein: The operation instruction includes a charging operation instruction and a discharging operation instruction. If the execution instruction is the operation instruction, the step of executing the second polling strategy based on the second state of charge value of the battery management system includes: If the operation instruction is the charging operation instruction, performing a full charging operation on the battery management system based on a preset first power condition and the second state of charge value; If the operation instruction is the discharge operation instruction, a full discharge operation is performed on the battery management system based on a preset second power condition and the second state of charge value.

4. The method for estimating state of charge according to claim 3, wherein: The step of performing a full charging operation on the battery management system based on the preset first power condition and the second state of charge value includes: sorting the second state of charge values ​​to obtain a charging calibration queue of the battery management system; determining, based on the charging calibration queue, whether a first power of the battery management system meets the first power condition; If the first power meets the first power condition, a full charging operation is performed on the battery management system.

5. The method for estimating state of charge according to claim 3, wherein: The step of performing a full discharge operation on the battery management system based on the preset second power condition and the second state of charge value includes: sorting the second state of charge values ​​to obtain a discharge calibration queue of the battery management system; determining, based on the discharge calibration queue, whether the second power of the battery management system meets the second power condition; If the second power meets the second power condition, a full discharge operation is performed on the battery management system.

6. The method for estimating state of charge according to claim 1, wherein: The state of charge estimation method further comprises the following steps: When executing the first polling strategy or the second polling strategy, obtaining a current event to determine whether an abnormality occurs in the current polling; If an exception occurs in the current polling, the current polling is exited.

7. A standard unit controller, characterized in that: The standard unit controller includes: An instruction receiving module is used to receive an execution instruction, wherein the execution instruction includes a stop instruction and a run instruction; a first polling module, configured to execute a first polling strategy based on a first state of charge value of a battery management system if the execution instruction is the shutdown instruction; a second polling module, configured to execute a second polling strategy based on a second state of charge value of the battery management system if the execution instruction is the run instruction; The first polling module is further configured to sort the first state of charge values ​​to obtain a shutdown calibration queue of the battery management system; Based on the shutdown calibration queue and a preset threshold, full charging and full discharging operations are performed on the battery management system.

8. A standard energy storage unit system, characterized in that: The energy storage standard unit system includes a standard unit controller, a battery management system, an energy management system, and a communication network; The energy management system is used to send execution instructions to the standard unit controller via the communication network; The standard unit controller is configured to receive the execution instruction, wherein the execution instruction includes a shutdown instruction and a run instruction; if the execution instruction is the shutdown instruction, execute a first polling strategy based on the first state of charge value of the battery management system; if the execution instruction is the run instruction, execute a second polling strategy based on the second state of charge value of the battery management system; The step of executing the first polling strategy based on the first state of charge value of the battery management system includes: sorting the first state of charge values ​​to obtain a shutdown calibration queue of the battery management system; performing full charge and full discharge operations on the battery management system based on the shutdown calibration queue and a preset threshold; The battery management system is configured to execute the first polling strategy or the second polling strategy.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a state-of-charge estimation program, which, when executed by a standard unit controller, implements the steps of the state-of-charge estimation method according to any one of claims 1 to 6.

Images