Dual-branch parallel control method based on group string energy storage and related equipment

Abstract

The application relates to the technical field of battery energy storage, in particular to a double-branch parallel control method based on group string energy storage and related equipment. The method comprises the following steps: collecting battery cluster parameters and energy storage converter parameters; combining the parameters and system requirements for coupling calculation, synchronously outputting a double-branch dynamic power distribution ratio for normal working condition output regulation and control, a fault judgment result and an operation mode switching instruction; then performing logical response on the fault judgment and mode switching instruction to generate a branch actual operation condition; finally, combining the battery cluster parameters, the branch condition and a power grid dispatching instruction to comprehensively solve and output an optimal power distribution strategy of the system. The method can greatly reduce fault loss, improve system utilization and finely regulate power.

Description

Technical Field

[0001] This application relates to the field of battery energy storage technology, and in particular to a dual-branch parallel control method and related equipment based on string energy storage. Background Technology

[0002] With the continuous expansion of new energy power generation, electrochemical energy storage systems are increasingly widely used in grid-side, user-side, and new energy distribution and storage fields. The existing mainstream architectures are divided into two categories: centralized and string-type. Centralized architectures, due to multiple battery clusters connected in parallel to a high-power PCS, suffer from problems such as inter-cluster circulating current, limited system utilization, and a large impact range from single-point failures. String-type architectures, on the other hand, avoid inter-cluster circulating currents because each battery cluster is independently connected to a PCS branch, making them the mainstream application solution. However, traditional string-type energy storage systems still have many technical shortcomings: incomplete fault isolation, where a single branch PCS failure can cause the entire battery cluster to shut down, resulting in a high failure loss rate; inability to dynamically adjust branch operation strategies based on battery status, making it difficult to improve system utilization; fixed power per branch with coarse power granularity, hindering fine-grained power scheduling; and the need for shutdown and maintenance of faulty branches, leading to high maintenance costs and severely impacting overall system availability. These shortcomings restrict the performance improvement and large-scale application of string-type energy storage systems.

[0003] In summary, the technical problems existing in the relevant technologies need to be improved. Summary of the Invention

[0004] The main objective of this application is to propose a dual-branch parallel control method and related equipment based on string energy storage, which can significantly reduce fault losses, improve system utilization, and finely schedule power.

[0005] To achieve the above objectives, one aspect of this application proposes a dual-branch parallel control method based on string energy storage. The method is applied to a string dual-branch energy storage system, which includes multiple battery clusters, multiple dual-branch energy storage converters, and a coordination controller. Each battery cluster is equipped with one of the dual-branch energy storage converters. The method includes the following steps: Obtain the battery cluster parameters and the energy storage converter parameters of the dual-branch energy storage converter; Based on the battery cluster parameters, the energy storage converter parameters, and the system functional requirements, coupled calculations are performed to obtain the dual-branch dynamic power allocation ratio, fault determination results, and operating mode switching instructions; wherein, the dual-branch dynamic power allocation ratio is used for branch output regulation under normal operating conditions. Logical responses are made to the fault determination results and the operation mode switching instructions to obtain the actual operating conditions of the branch. The optimal power allocation strategy is obtained by comprehensively solving the battery cluster parameters, the actual operating conditions of the branch, and the external power grid dispatch instructions.

[0006] In some embodiments, a single dual-branch energy storage converter includes two power branches connected in parallel. Both of the power branches are arranged in parallel on both the DC and AC sides; Each of the aforementioned power branches is equipped with a solid-state switch and a circuit breaker; The positive and negative busbars of the battery cluster are respectively connected to the DC side of the two power branches; The output terminals of the AC side of the two power branches are connected to the power grid after being stepped up by a transformer.

[0007] In some embodiments, the battery cluster parameters include voltage, current, temperature, and state of charge parameters; The parameters of the energy storage converter include operating status, fault status, and temperature status data.

[0008] In some embodiments, the step of logically responding to the fault determination result and the operating mode switching command to obtain the actual operating condition of the branch includes the following steps: Based on the fault determination results, the branch fault types are matched and identified to obtain the branch fault characteristic signals; The branch execution logic is matched and assigned values ​​according to the branch fault characteristic signal and the operation mode switching instruction to obtain the fault branch isolation execution signal and the target operation mode identifier. The signal synchronization start power pre-compensation algorithm is performed based on the fault branch isolation execution signal, and the output power of the healthy branch is adjusted in real time according to the target operating mode identifier to obtain the actual operating conditions of the branch. The branch fault types include abnormal branch current, insulated gate bipolar transistor (IGBT) fault, and communication fault.

[0009] In some embodiments, the operating modes of the operating mode switching instruction include dual-branch equal distribution mode, dual-branch proportional allocation mode, and single-branch independent operating mode; When there is no fault in the two power branches of the dual-branch energy storage converter, the dual-branch equal distribution mode or the dual-branch proportional distribution mode is selected to be enabled according to the dual-branch dynamic power distribution ratio. When any of the power branches of the dual-branch energy storage converter is faulty, the operating mode switching command of the single-branch independent operation mode is output to disconnect the faulty power branch, and the output power of the battery cluster is carried by the fault-free power branch.

[0010] In some embodiments, the step of performing coupled calculations based on the battery cluster parameters, energy storage converter parameters, and system functional requirements to obtain the dynamic power allocation ratio of the two branches includes the following steps: The total power demand of the string dual-branch energy storage system is calculated and solved based on the battery cluster parameters and the energy storage converter parameters to obtain the total power demand value. Based on the total power demand value and the current operating conditions of the power branch, the allocation logic of the power branch is matched and determined to obtain the power allocation coefficient. Based on the power allocation coefficient, the total power demand value is divided into branches and the power allocation coefficient is corrected to obtain the dynamic power allocation ratio of the dual branches. In the dual-branch equal distribution mode, the power allocation coefficient is set to a fixed preset value; in the dual-branch proportional distribution mode, the power allocation coefficient is calculated by querying the branch efficiency curve; and in the single-branch independent operation mode, the power allocation coefficient of the overloaded power branch is reduced.

[0011] In some embodiments, the step of performing coupled calculations based on the battery cluster parameters, energy storage converter parameters, and system functional requirements to obtain fault determination results and operating mode switching instructions includes the following steps: Based on the battery cluster parameters and the energy storage converter parameters, a preset fault threshold is compared and verified to obtain a branch fault triggering identifier. The validity of the branch fault event is determined based on the branch fault triggering identifier. When the branch fault triggering flag exists, the fault determination result is output and a fault isolation action signal for disconnecting the solid-state switch is sent. When the branch fault triggering identifier is not present, a fault clearing signal is output; The readiness of the electrical hardware status of the faulty branch is verified based on the fault clearing signal. When the verification passes, the system will switch to either the dual-branch equal distribution mode or the dual-branch proportional allocation mode. If the verification fails, the single-branch independent operation mode will be maintained.

[0012] To achieve the above objectives, another aspect of this application proposes a dual-branch parallel control device based on string energy storage. The device is applied to a string dual-branch energy storage system, which includes multiple battery clusters, multiple dual-branch energy storage converters, and a coordination controller. Each battery cluster is equipped with one of the dual-branch energy storage converters. The device includes: The parameter acquisition module is used to acquire the battery cluster parameters of the battery cluster and the energy storage converter parameters of the dual-branch energy storage converter. The coupling calculation module is used to perform coupling calculations based on the battery cluster parameters, the energy storage converter parameters, and system functional requirements to obtain the dynamic power allocation ratio of the dual branches, the fault judgment result, and the operation mode switching command; wherein, the dynamic power allocation ratio of the dual branches is used for the output regulation of the branches under normal operating conditions. The logic response module is used to respond logically to the fault determination result and the operation mode switching instruction to obtain the actual operating conditions of the branch. The strategy output module is used to perform a comprehensive solution based on the battery cluster parameters, the actual operating conditions of the branch, and the external power grid dispatch instructions to obtain the optimal power allocation strategy.

[0013] To achieve the above objectives, another aspect of this application provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the method described above.

[0014] To achieve the above objectives, another aspect of the embodiments of this application proposes a computer-readable storage medium storing a computer program that, when executed by a processor, implements the methods described above.

[0015] The embodiments of this application include at least the following beneficial effects: This application provides a dual-branch parallel control method and related equipment based on string energy storage. This scheme synchronously collects battery cluster parameters and energy storage converter parameters, and then combines them with system functional requirements to couple and calculate and synchronously output three core control quantities: dynamic power allocation ratio of dual branches, fault judgment result, and operating mode switching command. On the one hand, it relies on the dynamic power allocation ratio to achieve fine-grained output adjustment of dual branches under fault-free operating conditions, and can adaptively allocate power according to branch efficiency, load, and temperature to improve the overall operating efficiency of the energy storage system. On the other hand, it synchronously completes fault identification and operating mode switching command generation, providing accurate basis for subsequent fault branch isolation and operating mode switching, avoiding the single-branch fault of traditional string energy storage. Faults directly cause capacity loss due to the shutdown of the entire cluster. Then, by coordinating the fault judgment results with the operation mode switching command and generating the actual operating conditions of the branch, the faulty branch is quickly isolated and the healthy branch seamlessly takes over all the power, which greatly reduces the power drop and downtime maintenance time caused by the fault. Finally, the optimal power allocation strategy is solved by combining the real-time status of the battery cluster, the current operating conditions of the branch and the grid dispatch command. It can take into account the battery health status, the hardware carrying capacity of the branch and the grid dispatch requirements. It not only solves the defects of traditional string energy storage such as incomplete fault isolation, coarse power granularity, low system utilization and high maintenance costs, but also realizes flexible power dispatch under all operating conditions, effectively improving the operational stability, capacity utilization and grid adaptability of the energy storage system. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a string dual-branch energy storage system; Figure 2 This is a schematic diagram of the topology of a two-branch parallel electrical system; Figure 3 This is a flowchart illustrating the dual-branch coordination control logic; Figure 4 This is a timing diagram for fault switching; Figure 5 This is a schematic diagram of the power pre-compensation curve; Figure 6 This is a diagram illustrating the efficiency comparison; Figure 7 This is a flowchart illustrating the dynamic power allocation ratio of the two branches; Figure 8 This is a flowchart illustrating the fault detection and state switching process. Figure 9 This is a schematic diagram of the power supply chassis structure; Figure 10 This is a schematic diagram of the battery cluster importance classification standard; Figure 11 This is a schematic diagram of the structure of the dual-branch parallel control device based on string energy storage provided in the embodiments of this application; Figure 12 This is a schematic diagram of the hardware structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit it. In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those of this application; they are merely examples of apparatuses and methods consistent with some aspects of the embodiments of this application as detailed in the appended claims.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0019] Before providing a detailed description of the embodiments of this application, some of the nouns and terms involved in the embodiments of this application will be explained first. The nouns and terms involved in the embodiments of this application are subject to the following interpretations.

[0020] PCS (Power Storage Converter): The core energy storage conversion device that enables bidirectional conversion between battery DC and grid AC power.

[0021] SOC (State of Charge): Characterizes the ratio of the remaining capacity of a battery to its rated capacity.

[0022] IGBT (Insulated Gate Bipolar Transistor): PCS power switching device.

[0023] AGC (Automatic Generation Control): The grid issues dispatch instructions, which serve as the real-time load input basis for software-defined power allocation.

[0024] DSP (Digital Signal Processor): The main control chip in the module, responsible for performing real-time calculations such as dynamic power allocation, fault state machine, and power pre-compensation.

[0025] SiC MOSFET (Silicon Carbide Metal Oxide Field Effect Transistor): A core device for solid-state switching, enabling rapid electrical isolation of faulty branches within 10ms.

[0026] FPGA (Field Programmable Gate Array): Together with DSP, it forms a dual collaborative control architecture, shortening branch communication latency and ensuring high-speed real-time hardware logic response.

[0027] Modbus TCP: An Ethernet industrial communication protocol used for data exchange between energy storage systems and upper-level monitoring and power grid dispatching backends.

[0028] CAN bus: A low-level high-speed fieldbus that enables low-latency real-time branch-based collaborative communication between power modules and control boards within the chassis.

[0029] This application proposes a dual-branch parallel control method suitable for string energy storage scenarios. The entire hardware platform is a string dual-branch energy storage system, which consists of three main parts: multiple battery clusters, multiple dual-branch energy storage converters (dual-branch PCS), and a coordination controller. Figure 1 , Figure 2 and Figure 3 As shown, the entire control method relies on the coordinating controller to complete the entire process of data acquisition, coupled calculation, fault logic response, and power comprehensive solution, and finally outputs the optimal power allocation strategy to achieve stable, reliable, and efficient grid-connected operation of the energy storage system.

[0030] Figure 1 The system intuitively demonstrates the hardware hierarchy of a single string dual-branch energy storage system. It adopts a modular unit design, and the string dual-branch energy storage system consists of three levels of equipment connected in series from top to bottom: battery clusters, dual-branch PCS, and a coordination controller. Figure 1The upper layer consists of multiple identical battery clusters arranged horizontally. The rated capacity of each battery cluster is preferably 418 kWh, and the rated voltage is preferably 1331.2 V. Six clusters are preferably grouped into a standard unit, and so on. A total of 12 identical battery clusters can be combined to form a containerized energy storage system with a total capacity of 5 MWh. Each battery cluster is vertically connected downwards via a DC bus and independently connected to a dual-branch PCS. Figure 1 The battery clusters correspond one-to-one with PCS1-PCSn. Each dual-branch PCS is preferably rated at 2×225kW, and internally it is preferably integrated with two independent 225kW power branches.

[0031] All dual-branch PCS are uniformly connected to the coordination controller at the underlying level. Figure 1 The system identifies the data and control interaction links between multiple dual-branch PCSs and the coordination controller. The coordination controller, as the core computing and control hub of the entire system, collects operating parameters from all battery clusters and dual-branch PCSs, executes the entire dual-branch parallel control algorithm, completes all computational logic such as power allocation calculation, fault diagnosis, and operating mode switching, and finally issues control commands to the two power branches within each dual-branch PCS. It is the core carrier for achieving the optimal power allocation strategy. The entire unit can be expanded in parallel with multiple groups; 12 battery clusters paired with a corresponding number of dual-branch PCSs form a standardized 5MWh containerized energy storage system.

[0032] Figure 2 The hardware layout of the two power branches with full parallel connection on both the DC and AC sides is clearly displayed. This topology is the hardware foundation for dynamic power distribution and fault isolation switching of the two branches, and directly determines the conditions for realizing the optimal power distribution strategy. At the top of the topology is the DC bus of the battery cluster, with the rated parameters preferably 418kWh / 1331.2V. The positive and negative DC buses of the battery cluster branch out into two separate paths, which are connected to the left power branch 1 and the right power branch 2, respectively, to achieve parallel connection on the DC side. The hardware configuration of the two branches is completely symmetrical. Power branch 1 is equipped with solid-state switch 1 and circuit breaker 1, and power branch 2 is equipped with solid-state switch 2 and circuit breaker 2. The solid-state switch is responsible for millisecond-level fast disconnection, and the circuit breaker provides long-term isolation protection. The two work together to safely disconnect the faulty branch. The two AC output terminals of the preferred 225kW power branches are connected in parallel. The rated output voltage of the AC side is 690V. After the two AC buses are combined, they are connected to the step-up transformer. The preferred transformer ratio is 690V / 35kV. After being stepped up by the transformer, the AC side is connected to the power grid through the 35kV AC bus, realizing parallel grid connection of the AC side.

[0033] From a power distribution perspective, the DC and AC parallel topology enables the two power branches to independently carry and collaboratively output power: when there is no fault, the two branches can simultaneously carry the output power of the battery cluster, supporting two dual-branch power regulation modes: equal distribution and proportional distribution; when a single branch fails, the faulty branch can be quickly disconnected by a solid-state switch or circuit breaker, and the DC and AC circuits of the remaining healthy branch are fully connected, enabling it to independently carry the full power of the battery cluster. This provides hardware assurance for the independent operation mode of a single branch and is also a prerequisite for the subsequent coupled calculation and fault logic response stages to output three types of operating modes and solve the optimal power distribution strategy.

[0034] Figure 3 From the start to the end of the closed-loop process, the system covers all steps including data acquisition, coupled calculation, fault logic response, and power synthesis solution, fully reproducing the entire process of generating the optimal power allocation strategy. The entire control process runs continuously in a loop, ensuring real-time dynamic regulation of the energy storage system. First, status monitoring is performed to collect all basic parameters, providing raw data for power calculation. The process starts at "Start," and the first execution step is to collect the operating status of the battery cluster and branches, corresponding to the "obtain battery cluster parameters and energy storage converter parameters" step in the control method, which is also the data source for the entire optimal power allocation solution. The coordinating controller collects two types of core parameters in real time: firstly, battery cluster parameters, including battery DC voltage, charging and discharging current, cell temperature, and battery SOC state of charge, used to determine the remaining battery capacity, charging and discharging capability, and thermal safety boundary; secondly, energy storage converter parameters for the dual-branch PCS, namely the real-time operating status of the two power branches, branch fault alarm signals, and power module IGBT temperature. After collection, all parameters are sent to the next logic judgment node, synchronously supplying subsequent coupled calculation steps.

[0035] Then, coupling calculations are performed, synchronously outputting power allocation ratios, fault determination, and mode switching commands: all acquired parameters enter the coupling calculation stage, corresponding to... Figure 3The "Power Allocation Calculation" module is the core computational step for generating the optimal allocation strategy. The coordinating controller combines real-time battery cluster parameters, energy storage converter parameters for both power branches, and system functional requirements such as grid dispatch and energy storage charging / discharging demands to perform coupled calculations, simultaneously outputting three key calculation results: The first is the dynamic power allocation ratio between the two branches, specifically used to adjust the output power ratio of the two branches under normal, fault-free operating conditions; the second is the branch fault determination result, identifying whether there are faults such as abnormal current, IGBT damage, or communication interruption in the branch; the third is the operating mode switching command, matching three operating modes based on the fault determination result: equal power distribution between the two branches, proportional power distribution between the two branches, and independent operation of a single branch. After the calculation is completed, the system enters the fault determination branch logic: if the fault determination result is "no fault," it directly jumps to the dual-branch coordinated control logic; if it determines "a branch fault exists," it triggers the fault isolation branch and executes the single-branch switching process.

[0036] Next, fault logic response is performed, fault characteristics are matched, and the actual operating conditions of the branch are determined: after the coupled calculation outputs the fault judgment result and the operating mode switching command, the logic response stage begins, corresponding to... Figure 3 The "Isolate Faulty Branch, Single Branch Operation" branch is used to determine the final actual operating conditions of the two power branches, thus defining the operating boundaries for the power comprehensive solution.

[0037] Based on the fault determination results, the fault type is identified, distinguishing between three types of fault characteristic signals: abnormal branch current, IGBT fault, and communication fault. Then, combining the fault characteristic signals with the operating mode switching command, the branch execution logic is matched to generate a faulty branch isolation execution signal and a target operating mode identifier. If a branch fault is determined, the coordinating controller synchronously sends an isolation signal to drive the solid-state switch, preferably disconnecting the faulty branch within 10ms. Simultaneously, a power pre-compensation algorithm is initiated, using the target operating mode identifier to real-time compensate and regulate the output power of the healthy branch, ensuring no significant drop in total output power. After isolation and power compensation are completed, the final actual operating conditions of the two branches are determined, such as one branch being shut down and isolated, and the other operating at full load. Under fault-free conditions, there is no fault isolation action; the operating condition of synchronous output of the two branches is directly determined based on the dynamic power distribution ratio of the two branches, and both branches maintain grid-connected operation.

[0038] Finally, a comprehensive solution is obtained to generate the optimal power allocation strategy and output control commands: After acquiring the actual operating conditions of the branch, a comprehensive solution is performed by combining the previously collected full parameters of the battery cluster, the current operating conditions of the branch, and the externally issued grid dispatch commands. This ultimately yields the optimal power allocation strategy for the entire system. Figure 3The "output control command" stage. This strategy is divided into three categories to adapt to different operating conditions: When both branches are fault-free, the dual-branch equal distribution mode or dual-branch proportional distribution mode is selected, and the output of the two branches is allocated according to the dynamic power distribution ratio obtained by coupling calculation, taking into account the balance of branch loss and battery charging and discharging; When any branch fails, the single-branch independent operation mode is activated, the faulty branch is completely isolated, and all charging and discharging power is carried by the healthy branch alone, while relying on the pre-compensation algorithm to ensure the stability of grid-connected power.

[0039] After the optimal power allocation strategy is generated, the coordinating controller sends unified control commands to each dual-branch PCS, driving the two power branches to output the corresponding power according to the allocation strategy. After the command is issued, the system enters the "continue" judgment node. If it continues to run, it jumps to the front end of the process, re-collects the battery and branch status, and repeats the entire control process. If it stops running, it directly enters the "end" node, and the entire dual-branch parallel control process closes in a closed loop.

[0040] comprehensive Figure 1 , Figure 2 and Figure 3 Complete implementation of dual-branch parallel control and optimal power distribution: Figure 1 Determine the hierarchical relationship between the battery cluster, dual-branch PCS, and coordination controller, and provide the hardware carrier; Figure 2 By relying on the DC and AC dual-side parallel topology, an electrical hardware foundation for dual-branch coordinated output and fault isolation is built to support the implementation of three operating modes; Figure 3 With the coordinating controller as the core of the operation, following the complete steps of "parameter acquisition, coupled calculation, fault logic response, and power comprehensive solution", and relying on real-time data of batteries and branches and grid dispatch requirements, the dynamic power allocation ratio of the two branches is dynamically calculated, branch faults are identified and rapid isolation switching is completed, and the corresponding optimal power allocation strategy is output according to the operating conditions. During normal operation, the dual-branch power balance optimization is achieved, and the uninterrupted and stable grid-connected operation of the energy storage system is ensured when a branch fault occurs, which greatly improves the operational reliability and power regulation economy of the string energy storage system.

[0041] In some embodiments, the dual-branch parallel control method based on string energy storage, according to the hardware topology of dual-branch DC and AC parallel connection and the hierarchical closed-loop control logic of the coordination controller, combines... Figure 4 , Figure 5 and Figure 6 It fully demonstrates five outstanding benefits, achieving significant technological breakthroughs in the dimensions of fault reduction, system utilization, scheduling precision, operation and maintenance capabilities, and switchover smoothness.

[0042] Firstly, it can significantly reduce failure losses. In traditional single-branch string energy storage solutions, once the PCS fails, the entire 418kWh battery cluster will directly shut down, resulting in a 100% power loss. This application relies on a dual-branch independent and controllable architecture and fault isolation control logic. When a single branch fails, only the faulty branch will be disconnected, while the other healthy branch can continue to take over the full power output of the battery cluster. A single 2×225kW dual-branch PCS only loses 225kW of power from a single branch, reducing the power loss from failure to 50%. Compared with traditional solutions, the failure loss can be reduced by up to 92%, significantly reducing the power generation and revenue losses caused by failures.

[0043] Secondly, this method effectively improves the overall system utilization rate, combined with Figure 6 This advantage can be visually demonstrated. Figure 6 The blue curve represents the efficiency of a traditional 450kW single-branch PCS system, while the red curve represents the efficiency of the 2×225kW dual-branch PCS system of this application. Within the normal operating range of the energy storage system at low to medium load rates of 30%-70%, the red dual-branch curve is consistently significantly higher than the blue single-branch curve. The lowest system efficiency of the single-branch solution in this range is only 89.4%. The coordinating controller collects real-time data on battery cluster voltage, current, temperature, SOC parameters, as well as the operating, fault, and temperature status data of the two power branches. It dynamically performs coupled calculations based on battery health status and grid power demand, flexibly switching between two normal operating modes: equal distribution of power between the two branches and proportional distribution of power between the two branches. This optimizes the output ratio of the two branches, avoiding situations where one branch is overloaded for a long time while the other branch is idle and wasted. Ultimately, this improves the overall utilization rate of the energy storage system by 6%-8%, fully tapping the operating potential of the battery and the converter.

[0044] This method then achieves a refined upgrade in power dispatching. The rated power of a single branch is only 225kW. With a configuration of 450kW total power using a single branch as the smallest regulating unit, the power regulation granularity is finer compared to the traditional 1250kW large-capacity single PCS solution. Combined with the power optimization dispatching strategy of the coordinating controller, it can accurately respond to small-amplitude regulation commands from the power grid, significantly improving dispatching flexibility and making it more suitable for business scenarios with stringent requirements for regulation accuracy, such as power grid AGC frequency regulation.

[0045] Next, it supports online maintenance of faulty branches without shutting down. Each power branch is independently equipped with solid-state switches and circuit breakers. When a branch fails, the control system can issue an isolation command to disconnect the AC and DC circuits of the faulty branch. The remaining healthy branches continue to operate in grid-connected mode without interruption. Maintenance personnel can directly carry out repair and component replacement work on the isolated faulty branch, shortening the maintenance window period that traditional solutions require several hours of downtime to zero, greatly improving the efficiency of power plant operation and maintenance and the duration of continuous operation.

[0046] Finally, it can achieve a highly smooth fault switching process with minimal impact on the power grid. Figure 4 From the perspective of time-axis segmented control logic, fault switching is divided into three stages: detection, switching, and recovery. The fault detection time is less than 5ms, the solid-state switch fault isolation action time is less than 10ms, and the total time from fault triggering to switching completion is controlled within 150ms. (This is in contrast to...) Figure 5 The power comparison curves clearly show that the traditional scheme without power pre-compensation (red curve) experiences a maximum power drop of up to 15% after a fault, resulting in a large power shortfall and slow recovery. In contrast, the control scheme using this power pre-compensation algorithm (blue curve) only experiences a brief overshoot of no more than 10%, quickly returning to near the ideal 450kW power baseline. The overall power fluctuation is controlled within 5%, which is consistent with... Figure 4 The millisecond-level phased timing control enables rapid fault isolation and seamless mode switching. It also relies on power pre-compensation algorithms to fill power gaps in advance and suppress fluctuation overshoot, thus avoiding the impact of sudden power changes on the power grid and ensuring the quality of grid-connected power and the stability of grid operation.

[0047] Overall, this dual-branch parallel control method addresses the shortcomings of traditional single-branch energy storage solutions from multiple dimensions, including fault tolerance, operation optimization, scheduling adaptation, convenient operation and maintenance, and grid connection stability. It is suitable for diverse engineering scenarios such as containerized energy storage power stations and grid auxiliary frequency regulation, and has outstanding practical value and economic benefits.

[0048] In some embodiments, such as Figure 7 and Figure 8 As shown, during the coupled calculation based on battery cluster parameters, energy storage converter parameters, and system functional requirements, the dynamic power allocation ratio of the two branches, fault determination results, and operating mode switching commands are simultaneously calculated. The calculation process for the dynamic power allocation ratio of the two branches is described in detail below. Figure 7 The dynamic power allocation algorithm process is as follows: First, based on the collected battery cluster parameters, branch efficiency, temperature, and load rate parameters of the energy storage converter, the total system power demand is calculated. Second, the total power demand is combined with the current operating conditions of the power branches to determine the allocation logic and output the power allocation coefficient. The allocation logic includes three modes: a dual-branch equal-sharing mode with a fixed preset coefficient of 0.5; when the total power is less than or equal to the rated power of a single branch, single-branch operation is used; when it exceeds the rated power, the total power is shared equally between the two branches; an optimized allocation mode retrieves the branch efficiency curve to calculate the optimal allocation coefficient α; and a branch protection mode specifically lowers the allocation coefficient for overloaded branches. Third, the power allocation coefficient is used to perform branch allocation calculations based on the total power value, using the formula... , After obtaining the power of the two branches, the power command is sent to the DSP and the allocation coefficient α is corrected in real time through a closed loop. After iterative optimization, the final dynamic power allocation ratio of the two branches is output. The solution for the fault determination result and the operation mode switching command is based on... Figure 8 The fault detection and switching state machine implementation involves two steps. First, parameters collected from the battery cluster and energy storage converter are compared and verified against preset fault thresholds. These thresholds include overcurrent > 1.2In, overtemperature > 85℃, hardware failure, and communication timeout > 100ms. After comparison, a branch fault trigger identifier is generated. Second, the validity of the fault event is confirmed based on the fault trigger identifier. If a valid fault trigger identifier exists, the fault determination result is output and simultaneously sent to the SiC. The MOSFET solid-state switch disconnects the isolation signal, relying on the solid-state circuit breaker to quickly disconnect the faulty branch within 10ms. If there is no fault trigger indicator, a fault clearing signal is output. The third step verifies the electrical readiness status of the faulty branch based on the fault clearing signal. If the verification passes, a switching command is generated to switch to the dual-branch even distribution mode or the dual-branch proportional distribution mode. After a soft start to achieve a smooth power transition, the normal operation state of the dual-branch coordinated distribution is restored. If the verification fails, the single-branch independent operation mode is maintained, with the healthy branch carrying all power and the fault clearing status being continuously monitored. The entire coupling calculation relies on the dual-branch PCS topology hardware foundation with parallel DC and AC sides and equipped with solid-state switches and circuit breakers for graded protection. It is combined with a dual-DSP+FPGA coordinated control architecture to achieve a branch communication delay of less than 1ms. It is compatible with Modbus TCP and CAN communication protocols to ensure real-time parameter interaction. The formula for calling the power pre-compensation algorithm during fault switching is: ; Where k=0.1, τ=20ms, This represents the power compensation output value at time t, in kW; it also represents the compensation power that the healthy branch needs to be superimposed at the moment of fault switching, used to fill the power gap caused by the disconnection of the faulty branch, ensuring a stable total output power of the system. This represents the current total output power required by the battery cluster, in kW; k represents the compensation gain coefficient, which is fixed at k=0.1 in this scheme; and t represents the time elapsed after the fault isolation action is completed, in ms. This represents the compensation attenuation time constant. The power pre-compensation algorithm compensates for power fluctuations, avoids switching impacts on the power grid, and fully covers the following states: normal operation (normal operating condition with parallel power distribution of two branches), fault detection (identifying abnormal signals such as overcurrent, overtemperature, hardware failure, and communication timeout), fault isolation (controlling the solid-state switch to disconnect the faulty branch within 10ms to perform electrical isolation), single-branch operation mode (after the faulty branch is disconnected, only the healthy branch carries the full power of the battery cluster), and fault recovery detection (continuously verifying whether the fault has been eliminated and whether the branch hardware meets the conditions for reconnection). This full-state switching logic enables parallel and collaborative computation of power distribution and fault mode determination.

[0049] In some embodiments, such as Figure 9 and Figure 10 As shown, Figure 10 The grading standard, referencing GB 50052, classifies battery clusters into three categories based on load level, economic losses caused by power outages, and impact on personal safety: For critical clusters such as hospitals, data centers, and emergency lighting, where power outages would result in significant losses, a dual-branch UPS backup architecture is configured, employing N+1 redundancy backup requirements; for important clusters such as industrial production lines and commercial complexes, where power outages would disrupt normal operations, only a dual-branch structure is configured with a hot standby backup mode; for general industrial and commercial power supplies where power outages only have a minor impact, a simplified single-branch configuration without redundancy backup is used to balance system construction costs and power supply reliability. This also allows for three types of extended topology schemes and software-defined power allocation schemes to adapt to different application scenarios. The first is a three-branch or higher parallel scheme, extending the dual-branch architecture to 3×150kW, 4×112.5kW, etc., reducing capacity loss from single-branch failures to 33% and 25%, respectively, suitable for ultra-high reliability scenarios, but increasing the computational complexity of the control algorithm; the second is a modular hot-swappable scheme, based on… Figure 9 As shown, the chassis houses multiple 56.25kW standardized pluggable power modules, equipped with an independent DSP control board, dual communication links of CAN bus and Ethernet, independent cooling fans, and dedicated AC / DC terminals, enabling N+1 redundancy configuration. Faulty power modules can be automatically bypassed, allowing the system to continue operating at reduced derating. Modules support individual disassembly and maintenance, significantly improving ease of operation and maintenance, but the overall hardware cost is higher. The third option is a hybrid topology solution, perfectly matched to... Figure 10The hierarchical logic employs a dual-branch architecture for battery clusters corresponding to critical loads, while a high-power single-branch architecture is used for battery clusters corresponding to ordinary loads. This differentiated configuration balances cost and power supply security. Fourthly, a software-defined power allocation scheme abandons physically fixed branch divisions, relying on control software to dynamically reorganize standardized power modules to generate virtual power branches. This scheme offers optimal adaptability and scheduling flexibility, but places stringent requirements on the underlying control algorithm and the stability of branch communication links. The complete process of the software-defined power allocation mechanism involves collecting grid AGC commands, local load forecast data, and battery cluster operating status constraints every 4 seconds as real-time demand inputs. When system power fluctuations exceed 20%, power modules malfunction, or there is a need for operational efficiency optimization, the branch reconfiguration process is triggered, sequentially completing the target power calculation, available power module status assessment, optimal module combination selection, soft-start smooth switching, and output power closed-loop adjustment. All the above branch topologies, redundancy configurations, and dynamic allocation functions are based on... Figure 9 The internal DSP control board performs the calculations in hardware, combined with... Figure 10 The tiered standard enables customized energy storage system topologies to be customized as needed, taking into account power supply reliability, operation and maintenance convenience, and project construction costs under different load levels.

[0050] Please see Figure 11 This application also provides a dual-branch parallel control device based on string energy storage, which can implement the above-mentioned method. The device is applied to a string dual-branch energy storage system, which includes multiple battery clusters, multiple dual-branch energy storage converters, and a coordination controller. Each battery cluster is equipped with a dual-branch energy storage converter. The device includes: The parameter acquisition module is used to acquire the battery cluster parameters and the energy storage converter parameters of the dual-branch energy storage converter. The coupling calculation module is used to perform coupling calculations based on battery cluster parameters, energy storage converter parameters, and system functional requirements to obtain the dynamic power allocation ratio of the two branches, fault judgment results, and operating mode switching instructions; among them, the dynamic power allocation ratio of the two branches is used for branch output regulation under normal operating conditions. The logic response module is used to respond logically to fault determination results and operating mode switching commands to obtain the actual operating conditions of the branch. The strategy output module is used to perform a comprehensive solution based on battery cluster parameters, actual branch operating conditions, and external power grid dispatch instructions to obtain the optimal power allocation strategy.

[0051] It is understood that the content of the above method embodiments is applicable to the present device embodiments. The specific functions implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0052] This application also provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the above-described method. This electronic device can be any smart terminal, including tablet computers, in-vehicle computers, etc.

[0053] It is understood that the content of the above method embodiments is applicable to this device embodiment. The specific functions implemented by this device embodiment are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0054] Please see Figure 12 , Figure 12 The hardware structure of an electronic device according to another embodiment is illustrated. The electronic device includes: The processor 121 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application. The memory 122 can be implemented as a read-only memory (ROM), static storage device, dynamic storage device, or random access memory (RAM). The memory 122 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 122 and is called and executed by the processor 121 using the methods described above in the embodiments of this application. Input / output interface 123 is used to implement information input and output; The communication interface 124 is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, network cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.). Bus 125 transmits information between various components of the device (e.g., processor 121, memory 122, input / output interface 123, and communication interface 124); The processor 121, memory 122, input / output interface 123 and communication interface 124 are connected to each other within the device via bus 125.

[0055] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method.

[0056] It is understood that the content of the above method embodiments is applicable to this storage medium embodiment. The specific functions implemented in this storage medium embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0057] The embodiments described in this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided by the embodiments of this application. As those skilled in the art will know, with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0058] Those skilled in the art will understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of this application, and may include more or fewer steps than shown, or combine certain steps, or different steps.

[0059] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0060] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0061] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0062] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0063] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0064] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0065] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A dual-branch parallel control method based on string energy storage, characterized in that, The method is applied to a string dual-branch energy storage system, which includes multiple battery clusters, multiple dual-branch energy storage converters, and a coordination controller. Each battery cluster is equipped with one of the dual-branch energy storage converters. The method includes the following steps: Obtain the battery cluster parameters and the energy storage converter parameters of the dual-branch energy storage converter; Based on the battery cluster parameters, the energy storage converter parameters, and the system functional requirements, coupled calculations are performed to obtain the dual-branch dynamic power allocation ratio, fault determination results, and operating mode switching instructions; wherein, the dual-branch dynamic power allocation ratio is used for branch output regulation under normal operating conditions. Logical responses are made to the fault determination results and the operation mode switching instructions to obtain the actual operating conditions of the branch. The optimal power allocation strategy is obtained by comprehensively solving the battery cluster parameters, the actual operating conditions of the branch, and the external power grid dispatch instructions.

2. The method according to claim 1, characterized in that, Each of the aforementioned dual-branch energy storage converters includes two power branches connected in parallel. Both of the power branches are arranged in parallel on both the DC and AC sides; Each of the aforementioned power branches is equipped with a solid-state switch and a circuit breaker; The positive and negative busbars of the battery cluster are respectively connected to the DC side of the two power branches; The output terminals of the AC side of the two power branches are connected to the power grid after being stepped up by a transformer.

3. The method according to claim 1, characterized in that, The battery cluster parameters include voltage, current, temperature, and state of charge parameters; The parameters of the energy storage converter include operating status, fault status, and temperature status data.

4. The method according to claim 1, characterized in that, The logic response to the fault determination result and the operation mode switching command is performed to obtain the actual operating condition of the branch. Includes the following steps: Based on the fault determination results, the branch fault types are matched and identified to obtain the branch fault characteristic signals; The branch execution logic is matched and assigned values ​​according to the branch fault characteristic signal and the operation mode switching instruction to obtain the fault branch isolation execution signal and the target operation mode identifier. The signal synchronization start power pre-compensation algorithm is performed based on the fault branch isolation execution signal, and the output power of the healthy branch is adjusted in real time according to the target operating mode identifier to obtain the actual operating conditions of the branch. The branch fault types include abnormal branch current, insulated gate bipolar transistor (IGBT) fault, and communication fault.

5. The method according to claim 1, characterized in that, The operating modes of the operation mode switching command include dual-branch even distribution mode, dual-branch proportional allocation mode, and single-branch independent operation mode. When there is no fault in the two power branches of the dual-branch energy storage converter, the dual-branch equal distribution mode or the dual-branch proportional distribution mode is selected to be enabled according to the dual-branch dynamic power distribution ratio. When any of the power branches of the dual-branch energy storage converter is faulty, the operating mode switching command of the single-branch independent operation mode is output to disconnect the faulty power branch, and the output power of the battery cluster is carried by the fault-free power branch.

6. The method according to claim 5, characterized in that, The process of performing coupled calculations based on the battery cluster parameters, energy storage converter parameters, and system functional requirements to obtain the dynamic power allocation ratio of the two branches includes the following steps: The total power demand of the string dual-branch energy storage system is calculated and solved based on the battery cluster parameters and the energy storage converter parameters to obtain the total power demand value. Based on the total power demand value and the current operating conditions of the power branch, the allocation logic of the power branch is matched and determined to obtain the power allocation coefficient. Based on the power allocation coefficient, the total power demand value is divided into branches and the power allocation coefficient is corrected to obtain the dynamic power allocation ratio of the dual branches. In the dual-branch equal distribution mode, the power allocation coefficient is set to a fixed preset value; in the dual-branch proportional distribution mode, the power allocation coefficient is calculated by querying the branch efficiency curve; and in the single-branch independent operation mode, the power allocation coefficient of the overloaded power branch is reduced.

7. The method according to claim 5, characterized in that, The process of performing coupled calculations based on the battery cluster parameters, energy storage converter parameters, and system functional requirements to obtain fault determination results and operating mode switching instructions includes the following steps: Based on the battery cluster parameters and the energy storage converter parameters, a preset fault threshold is compared and verified to obtain a branch fault triggering identifier. The validity of the branch fault event is determined based on the branch fault triggering identifier. When the branch fault triggering flag exists, the fault determination result is output and a fault isolation action signal for disconnecting the solid-state switch is sent. When the branch fault triggering identifier is not present, a fault clearing signal is output; The readiness of the electrical hardware status of the faulty branch is verified based on the fault clearing signal. When the verification passes, the system will switch to either the dual-branch equal distribution mode or the dual-branch proportional allocation mode. If the verification fails, the single-branch independent operation mode will be maintained.

8. A dual-branch parallel control device based on string energy storage, characterized in that, The device is applied to a string dual-branch energy storage system, which includes multiple battery clusters, multiple dual-branch energy storage converters, and a coordination controller. Each battery cluster is equipped with one of the dual-branch energy storage converters. The device includes: The parameter acquisition module is used to acquire the battery cluster parameters of the battery cluster and the energy storage converter parameters of the dual-branch energy storage converter. The coupling calculation module is used to perform coupling calculations based on the battery cluster parameters, the energy storage converter parameters, and system functional requirements to obtain the dynamic power allocation ratio of the dual branches, the fault judgment result, and the operation mode switching command; wherein, the dynamic power allocation ratio of the dual branches is used for the output regulation of the branches under normal operating conditions. The logic response module is used to respond logically to the fault determination result and the operation mode switching instruction to obtain the actual operating conditions of the branch. The strategy output module is used to perform a comprehensive solution based on the battery cluster parameters, the actual operating conditions of the branch, and the external power grid dispatch instructions to obtain the optimal power allocation strategy.

9. An electronic device, characterized in that, The electronic device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1 to 7.

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