Hybrid inverter two-way battery grid-connected power distribution method

Abstract

This application relates to a method for power allocation in a hybrid inverter with dual-battery grid connection, applied in the field of power electronics. The method includes determining the operating mode of both batteries; if both batteries are in charging mode or discharging mode, calculating a final allocation coefficient based on their capacity and state of charge (SOC); determining the total system power limit based on the operating modes of the dual batteries; and allocating power between the dual batteries according to the final allocation coefficient and the total system power limit. The technical advantage of this application is that it achieves dynamic SOC balancing and safe power allocation between the two batteries.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a method for power distribution of a hybrid inverter with dual-battery grid connection. Background Technology

[0002] Grid connection refers to connecting power generation equipment (such as photovoltaic, wind power, and energy storage systems) to the public power grid (national or local grid) through inverters and other equipment, and transmitting the generated electricity to users. With the rapid development of new energy sources, in grid-connected energy storage systems, a single battery often struggles to meet all performance indicators. To address this issue, the combination of hybrid inverters and dual independent batteries has emerged, creating a highly efficient, reliable, and economical energy storage solution.

[0003] When a hybrid inverter has two independent battery packs connected, the existing power allocation strategy usually adopts a single static capacity allocation, which leads to unreasonable allocation coefficient settings and may result in unreasonable power allocation. Summary of the Invention

[0004] To address the issue of potential SOC deviation amplification caused by single static capacity allocation without dynamic SOC deviation correction, this application provides a dual-battery grid-connected power allocation method for hybrid inverters, employing the following technical solution: The method includes:

[0005] Determine the operating mode of the dual-battery system; If both batteries are in charging mode or both are in discharging mode, the final allocation coefficient of the two batteries is calculated based on their capacity and state of charge. The total system power limit is determined based on the operating mode of the dual-battery system. The power of the dual batteries is allocated according to the final allocation coefficient and the total power limit of the system.

[0006] In one specific implementation, the calculation of the final allocation coefficient of the dual batteries based on their capacity and state of charge includes: Calculate the total effective capacity of the dual-battery system and determine whether the total effective capacity is greater than a preset capacity threshold. If the total effective capacity is greater than the preset capacity threshold, the initial allocation coefficient of the dual-battery is calculated, and the charge difference between the dual-battery is calculated. The allocation correction coefficient is calculated based on the charge difference value and the preset charge difference threshold; The final allocation coefficients of the dual-battery system are calculated based on the initial allocation coefficients and the allocation correction coefficients.

[0007] In one specific implementation, the calculation of the initial allocation coefficient for the dual-battery system includes: ， , in, Indicates the effective capacity of the first battery. Indicates the effective capacity of the second battery. This represents the initial allocation coefficient of the first battery. This represents the initial allocation coefficient of the second battery; The calculation of the charge difference between the two batteries includes: , in, This indicates the state of charge of the first battery. This indicates the state of charge of the second battery. This indicates the charge difference between the two batteries.

[0008] In one specific implementation, the calculation of the allocation correction coefficient based on the charge difference and a preset charge difference threshold includes: Determine whether the absolute value of the charge difference is less than a preset charge difference threshold; If the absolute value of the charge difference is less than the preset charge difference threshold, the allocation correction coefficient is set to 0; If the absolute value of the charge difference is not less than the preset charge difference threshold, then the product of the charge difference and the preset deviation ratio coefficient is set as the allocation correction coefficient.

[0009] In one specific implementation, calculating the final allocation coefficient of the dual-channel batteries based on the initial allocation coefficient and the allocation correction coefficient includes: Determine the operating mode of the dual-battery system; If both batteries are in charging mode, the final allocation coefficient for the two batteries is calculated as follows: , , in, This represents the final charging allocation coefficient of the first battery. This represents the final charging allocation factor for the second battery. This represents the initial allocation coefficient of the first battery. Indicates the allocation correction factor; If both batteries are in discharge mode, the final allocation coefficient for the two batteries is calculated as follows: , , in, This represents the final discharge distribution coefficient of the first battery. This represents the final discharge distribution coefficient of the second battery. This represents the initial allocation coefficient of the first battery. This represents the allocation correction factor.

[0010] In one specific implementation, after calculating the final allocation coefficient of the dual batteries based on their capacity and state of charge, the method further includes: The final allocation coefficient is subjected to amplitude limiting processing, and the amplitude-limited final allocation coefficient is set as the amplitude-limited allocation coefficient; The process of allocating power to the dual batteries based on the final allocation coefficient and the total system power limit includes: The power of the dual batteries is allocated according to the limiting allocation coefficient and the total power limit of the system.

[0011] In one specific implementation, the step of performing amplitude limiting processing on the final allocation coefficient and setting the amplitude-limited final allocation coefficient as the amplitude-limited allocation coefficient includes: Determine whether the final allocation coefficient is within the preset limit range; If the final allocation coefficient is within the preset limit range, then the final allocation coefficient is set as the limit allocation coefficient; If the final allocation coefficient is not within the preset limit range and is greater than the maximum value of the limit range, then the maximum value of the limit range is set as the limit allocation coefficient. If the final allocation coefficient is not within the preset limit range and is less than the minimum value of the limit range, then the minimum value of the limit range is set as the limit allocation coefficient.

[0012] In one specific implementation scheme, determining the total system power limit based on the operating mode of the dual-battery system includes: When both batteries are in charging mode, obtain the total power limit of system scheduling and the total power limit of dual battery charging. Compare the value of the total power limit for system scheduling with the value of the total power limit for dual-path battery charging, and set the maximum value as the total power limit for the system. When both batteries are in discharge mode, obtain the total power limit of system scheduling and the total power limit of dual battery discharge. Compare the total power limit of the system scheduling with the total power limit of the dual-path battery charging, and set the minimum value as the total power limit of the system.

[0013] In one specific implementation, the dual-channel battery comprises two single-channel batteries; after allocating the power of the dual-channel batteries according to the final allocation coefficient and the total system power limit, the method further includes: Set the power of the allocated dual batteries to the initial allocated power; Determine whether the initial power allocation of a single battery in the dual-battery system exceeds the maximum power limit of the corresponding battery. If no single battery has an initial power allocation exceeding the maximum power limit of the corresponding battery, then the initial power allocation of the dual batteries is the final power allocation of the dual batteries. If the initial power allocation of a single battery exceeds the maximum power limit of the corresponding battery, the power of the single battery exceeding the maximum power limit is clamped to the maximum power value of the battery, and the remaining power value is calculated. The remaining power value is compensated to another single-channel battery.

[0014] In one specific implementation scheme, before determining whether the total effective capacity is greater than a preset capacity threshold, the method further includes: Determine whether the total effective capacity is 0; If the total effective capacity is not 0, then determine whether the total effective capacity is greater than a preset capacity threshold. If the total effective capacity is 0, then the total power limit of the system is set to 0.

[0015] In summary, this application has the following beneficial technical effects: 1. Dual-factor coupling allocation coefficient calculation: Combining static capacity benchmark (initial allocation coefficient) and dynamic SOC deviation correction (allocation correction coefficient), the static benchmark factor is calculated based on the capacity ratio of the two batteries to ensure long-term power matching battery capability; the dynamic correction coefficient is calculated based on SOC deviation to achieve short-term rapid balancing, and thresholds and limits are set to avoid over-adjustment; 2. Reverse correction of charge and discharge: In charging mode, the final allocation factor = initial allocation coefficient × (1 - allocation correction coefficient), and high SOC batteries are allocated less charging power; in discharging mode, the final allocation factor = initial allocation coefficient × (1 + allocation correction coefficient), and high SOC batteries are allocated more discharging power, thus leveling off SOC deviation in both directions. 3. Power over-limit verification and compensation: After the initial power allocation, it is verified whether the power of a single battery exceeds the hardware limit. If it exceeds the limit, it is clamped to the maximum value, and the remaining power is compensated to the other battery. This ensures full load output, avoids hardware damage, and ensures the total power is kept constant. 4. Selecting power limits by mode: The charging mode selects a more stringent total power limit (larger value, negative power during charging), and the discharging mode selects a more stringent total power limit (smaller value, positive power during discharging), adapting to the power control requirements of different modes. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a system architecture for a hybrid inverter with dual battery access to the grid; Figure 2 This is a flowchart of the power distribution method for dual-battery grid connection of a hybrid inverter in an embodiment of this application; Figure 3 This is a flowchart illustrating the complete method for power distribution of a hybrid inverter with dual-battery grid connection in an embodiment of this application. Figure 4 This is a flowchart of the method for calculating the grid-connected power distribution coefficient of a dual-battery hybrid inverter in the embodiments of this application. Detailed Implementation

[0017] The following combination Figures 1-4 This application will be described in further detail.

[0018] This application discloses a method for power distribution in a hybrid inverter with dual-battery grid connection. This method enables balanced power distribution between the two batteries in grid-connected scenarios, and is applicable to the power balance control of the BMS for dual independent battery packs in hybrid inverters. It features fast balancing speed, high safety, and strong adaptability.

[0019] Grid connection refers to connecting power generation equipment (such as photovoltaic, wind power, and energy storage systems) to the public power grid (national or local grid) via inverters and other equipment, transmitting the generated electricity to users. With the rapid development of new energy sources, in grid-connected energy storage systems, a single battery often struggles to meet all performance indicators. To address this issue, the combination of hybrid inverters and dual-battery systems has emerged, creating a highly efficient, reliable, and economical energy storage solution. (Refer to...) Figure 1 This is a schematic diagram of a system architecture for a hybrid inverter with dual batteries connected to the grid. The system converts solar energy into electrical energy via photovoltaic panels, which is then input into the hybrid inverter. Simultaneously, dual batteries are connected to the hybrid inverter for energy storage. The inverter's output side is connected to a standby load and, via a current transformer, to the power grid.

[0020] When dual independent battery packs are connected to a hybrid inverter, existing power allocation strategies typically employ a single static capacity allocation without dynamic correction of State of Charge (SOC) deviation. This can lead to an amplification of SOC deviation and unreasonable power allocation. Secondly, existing power allocation methods use the same correction logic for both charging and discharging modes, resulting in low balancing efficiency. Furthermore, existing power allocation methods lack power over-limit verification and compensation mechanisms, making them prone to exceeding battery hardware limitations. Therefore, to facilitate dynamic SOC balancing and safe power allocation for dual batteries, this application provides a power allocation method for dual-battery grid-connected hybrid inverters.

[0021] Reference Figure 2 The method includes the following steps: S10 determines the operating mode of the dual-battery system.

[0022] Specifically, the system identifies and determines the battery's operating mode, detecting whether it is currently in charging or discharging mode. When the battery is in charging mode, the battery power is negative; when the battery is in discharging mode, the battery power is positive. The specific steps include: First, acquiring the energy storage system's dispatch power for the dual batteries. The battery's operating mode is determined based on the sign of the dispatch power: if the dispatch power is positive, the battery is in discharging mode; if the dispatch power is negative, the battery is in charging mode; if the dispatch power is 0, the power of both batteries is set to 0. Next, the system determines the enabling status of the dual batteries. If both batteries are enabled for charging in charging mode, both batteries are considered to be in charging mode; if both batteries are enabled for discharging in discharging mode, both batteries are considered to be in discharging mode. The enabling status is detected by comparing the values ​​of the enabling flags of the dual batteries acquired by the system with preset values.

[0023] S20. If both batteries are in charging mode or discharging mode, the final allocation coefficient of the two batteries is calculated based on their capacity and state of charge.

[0024] Specifically, when both batteries are enabled and either in charging or discharging mode, the final allocation coefficient of the two batteries is calculated based on their capacity and state of charge (SOC), and the power is allocated according to the allocation coefficient of the two batteries.

[0025] It should be noted that in charging mode, if only one battery is enabled, that enabled battery will handle all the charging power without any power allocation; if both batteries are disabled, the charging power of both batteries will be 0. Similarly, in discharging mode, if only one battery is enabled, that enabled battery will handle all the discharging power without any power allocation; if both batteries are disabled, the discharging power of both batteries will be 0.

[0026] S30 determines the total system power limit based on the dual-battery operating mode.

[0027] Specifically, the total system power limit is determined, and power allocation is performed based on the maximum power limit to ensure the safety of the system and the power grid. The specific determination method can be implemented as follows: When both batteries are in charging mode, the system's total power limit and the dual-battery charging power limit are obtained; the values ​​of the system's total power limit and the dual-battery charging power limit are compared, and the maximum value is set as the system's total power limit. That is, in charging mode, the maximum value of the two power limits is selected. When both batteries are in discharging mode, the system's total power limit and the dual-battery discharging power limit are obtained; the values ​​of the system's total power limit and the dual-battery charging power limit are compared, and the minimum value is set as the system's total power limit. That is, in discharging mode, the minimum value of the two power limits is selected. The total power limit can generally be obtained directly from the Energy Management System (EMS), Inverter Controller (VCU), or Battery Management System (BMS).

[0028] S40 allocates power to the dual batteries based on the final allocation factor and the total system power limit.

[0029] Specifically, after calculating the final allocation coefficient and the total system power limit, the total system power limit is multiplied by the final allocation coefficient of each of the two batteries to obtain the corresponding battery power, thereby realizing the power allocation of the dual batteries.

[0030] In this application, by combining static capacity and dynamic SOC, short-term rapid balancing is achieved. The allocation coefficient of the dual-battery circuit is calculated by comprehensively considering the changes in static capacity and dynamic SOC, thus achieving balanced distribution of the dual-battery circuits. Furthermore, by determining the battery's operating mode, different power limits are selected: a stricter total power limit (larger value, negative power during charging) is chosen for the charging mode, and a stricter total power limit (smaller value, positive power during discharging) is chosen for the discharging mode, to adapt to the power control requirements under different modes and achieve dynamic SOC balancing and safe power distribution of the dual batteries.

[0031] In one embodiment, the method for calculating the final allocation coefficient of the two batteries based on their capacity and state of charge can be specifically implemented as follows: First, calculate the total effective capacity of the dual-battery system and determine if it exceeds a preset capacity threshold. If the total effective capacity is less than the preset threshold, set the system's total power limit to 0. In this case, regardless of the calculated allocation coefficient, the power allocated to both batteries is 0; that is, when the total effective capacity of the two batteries is less than the threshold, the power of both batteries is 0. If the total effective capacity exceeds the preset threshold, calculate the initial allocation coefficient and the charge difference between the two batteries. The dual-battery system includes a first battery and a second battery. The initial allocation coefficient for the two batteries can be calculated as follows: ， , in, Indicates the effective capacity of the first battery. Indicates the effective capacity of the second battery. This represents the initial allocation coefficient of the first battery. This represents the initial allocation coefficient of the second battery; The charge difference between the two batteries can be calculated as follows: , in, This indicates the state of charge of the first battery. This indicates the state of charge of the second battery. This indicates the charge difference between the two batteries.

[0032] After calculating the initial allocation coefficient and charge difference, an allocation correction coefficient is calculated based on the charge difference and a preset charge difference threshold. Specifically, first, it is determined whether the absolute value of the charge difference is less than the preset charge difference threshold. If the absolute value of the charge difference is less than the preset charge difference threshold, the allocation correction coefficient is set to 0; that is, if... ,but ,in, This indicates the charge difference between the two batteries. This indicates the preset charge difference threshold. This represents the allocation correction factor.

[0033] If the absolute value of the charge difference is not less than the preset charge difference threshold, then the product of the charge difference and the preset deviation ratio coefficient is set as the allocation correction coefficient; that is, if ,but ,in, This indicates the charge difference between the two batteries. This indicates the preset charge difference threshold. Indicates the allocation correction factor. This represents the preset deviation ratio coefficient.

[0034] After calculating the initial allocation coefficient and the allocation correction coefficient, the final allocation coefficient for the dual-battery system is calculated based on these coefficients. Specifically, the operating mode of the dual-battery system is determined, and the final allocation coefficient is calculated based on the battery's charging / discharging mode.

[0035] If both batteries are in charging mode, the final allocation coefficient of the two batteries can be calculated as follows: , , in, This represents the final charging allocation coefficient of the first battery. This represents the final charging allocation factor for the second battery. This represents the initial allocation coefficient of the first battery. Indicates the allocation correction factor; If both batteries are in discharge mode, the final allocation coefficient of the two batteries can be calculated as follows: , , in, This represents the final discharge distribution coefficient of the first battery. This represents the final discharge distribution coefficient of the second battery. This represents the initial allocation coefficient of the first battery. This represents the allocation correction factor.

[0036] In this application, the allocation coefficient of the dual-battery system is determined through a dual-factor coupling allocation. Combining a static capacity benchmark and dynamic SOC deviation correction, the static benchmark factor, i.e., the initial allocation coefficient, is calculated based on the capacity ratio of the two batteries to ensure long-term power matching capability. The dynamic correction coefficient, i.e., the allocation correction coefficient, is calculated based on the SOC charge difference to achieve rapid short-term balancing. Furthermore, the allocation coefficient is corrected through reverse charge / discharge correction logic. In charging mode, the final allocation factor = static benchmark factor × (1 - dynamic correction coefficient), allocating less charging power to the high-SOC battery. In discharging mode, the final allocation factor = static benchmark factor × (1 + dynamic correction coefficient), allocating more discharging power to the high-SOC battery, thus bidirectionally balancing the SOC deviation and making the allocation coefficient setting of the dual-battery system more reasonable.

[0037] In one embodiment, considering that the calculated allocation coefficient may exceed the limit range, causing a final power allocation error, the following steps can be performed after calculating the final allocation coefficient of the dual batteries based on their capacity and state of charge: The final allocation coefficient is subjected to amplitude limiting processing, and the amplitude-limited final allocation coefficient is set as the amplitude-limited allocation coefficient. Specifically, it is determined whether the final allocation coefficient is within a preset amplitude limiting range. If the final allocation coefficient is within the preset amplitude limiting range, it is set as the amplitude-limited allocation coefficient; if the final allocation coefficient is not within the preset amplitude limiting range but is greater than the maximum value of the amplitude limiting range, the maximum value of the amplitude limiting range is set as the amplitude-limited allocation coefficient; if the final allocation coefficient is not within the preset amplitude limiting range but is less than the minimum value of the amplitude limiting range, the minimum value of the amplitude limiting range is set as the amplitude-limited allocation coefficient.

[0038] For example, assuming the allocation coefficient is limited to the range [0, 1], if the calculated final allocation coefficients for the two batteries are 0.4 and 0.6 respectively, and both 0.4 and 0.6 fall within the range [0, 1], then 0.4 and 0.6 are the limiting allocation coefficients. If the calculated final allocation coefficients for the two batteries are 1.2 and -0.2 respectively, then the allocation coefficient for one battery is greater than 1, and the allocation coefficient for the other battery is less than 0. In this case, the battery with a final allocation coefficient of 1.2 has its limiting allocation coefficient set to 1, and the battery with a final allocation coefficient of -0.2 has its limiting allocation coefficient set to 0.

[0039] The power allocated to the dual-battery circuits, based on the final allocation coefficient and the total system power limit, includes: the power allocated to the dual-battery circuits based on the limiting allocation coefficient and the total system power limit.

[0040] In this application, to avoid power allocation errors caused by unreasonable coefficient settings in practical applications, the allocation coefficient is limited to a reasonable range to ensure that power allocation can proceed normally.

[0041] In one embodiment, considering that the power allocated according to the allocation factor may result in the power of a single battery exceeding the maximum limit allowed by the hardware, the following steps may also be performed after allocating the power of the dual batteries according to the final allocation factor and the total system power limit: First, the power allocated to the dual-battery circuit is set as the initial allocated power. Then, it is determined whether the initial allocated power of any single battery circuit exceeds its maximum power limit. Since the dual-battery circuit comprises two single batteries, this can also be understood as determining whether the power allocated to the two single batteries exceeds their respective hardware's maximum power value. If no single battery's initial allocated power exceeds its maximum power limit, the initial allocated power of the dual-battery circuit is the final allocated power. Alternatively, if the power allocated to both single batteries is within their respective hardware's maximum power limit, the allocated power is maintained and operation continues. If a single battery's initial allocated power exceeds its maximum power limit, the power of that single battery exceeding its maximum power limit is clamped to the battery's maximum power value, and the remaining power value is calculated. This remaining power value is then compensated to the other single battery circuit. In other words, if the power allocated to one of the two single-channel batteries exceeds the maximum power limit allowed by the battery hardware, the power of that battery channel will be clamped to the maximum power allowed by the hardware. The remaining unallocated power will be calculated and compensated to the power of the other battery channel to ensure that the power of a single battery does not exceed its own hardware power limit and the total power is strictly conserved.

[0042] For example, assuming the calculated final allocation factor is 0.55 for battery 1 and 0.45 for battery 2, the total system power limit is 10000W, the maximum hardware power limit for battery 1 is 5000W, and the maximum hardware power limit for battery 2 is 5000W, then the initial allocated power for battery 1 is 5500W, and the initial allocated power for battery 2 is 4500W. Considering that the initial allocated power of battery 1 (5500W) is greater than the maximum hardware power limit of 5000W, the final allocated power for battery 1 is 5000W, and the remaining 500W is compensated to battery 2. The final allocated power for battery 2 is 5000W, and the total power is conserved and there is no over-limit.

[0043] In this application, after the initial power allocation, it is checked whether the power of a single battery exceeds the hardware limit. If it does, it is clamped to the maximum value, and the remaining power is compensated to the other battery. This ensures full-load output, avoids hardware damage through power over-limit verification and compensation logic, and ensures the conservation of total power.

[0044] In one embodiment, considering that the system's normal power distribution would be affected if the effective capacity of both batteries were zero, the following steps can be performed before determining whether the total effective capacity is greater than a preset capacity threshold: First, determine if the total effective capacity is 0; if the total effective capacity is not 0, then normally determine if the total effective capacity is greater than the preset capacity threshold; if the total effective capacity is 0, then set the total power limit of the system to 0 to perform abnormal protection and reduce the adverse effects of abnormal situations on the entire system.

[0045] In this application, considering that the normal power distribution of the system would be affected when the effective capacity of the two batteries is 0, anomaly protection is used to avoid operational anomalies.

[0046] Reference Figure 3 This is a complete flowchart of the dual-battery grid-connected power distribution method for hybrid inverters in this application embodiment. First, core control parameters are defined, including the charge difference threshold. And deviation ratio coefficient Next, the operating mode of the dual batteries is determined, and the charging / discharging enable status of both batteries is checked. If both batteries are disabled, or one is enabled for charging and the other for discharging, power is allocated according to the actual enable status. If both batteries are enabled for charging or discharging, the power allocation coefficient is calculated. First, it is determined whether the total capacity of the two batteries is greater than 0. If the total capacity of the two batteries is less than or equal to 0, the total system power limit is set to 0 to avoid calculation errors during operation. If the total capacity of the two batteries is greater than 0, the initial allocation coefficient and charge difference of the batteries are calculated first, and the final allocation coefficient of the batteries is calculated based on the initial allocation coefficient and charge difference, and the allocation coefficient is limited to the range of [0, 1]. After the allocation coefficient is calculated, the initial power is allocated according to the calculated allocation coefficient. It is determined whether the initial allocated power of the two batteries exceeds the hardware maximum power limit of the corresponding batteries. If neither exceeds the limit, the initial allocated power is maintained; if one battery exceeds the hardware maximum power limit of the corresponding battery, the power of that battery is clamped to the maximum power, and the remaining power is compensated to the other battery to achieve power conservation.

[0047] Reference Figure 4 This is a flowchart illustrating the calculation method of the dual-channel battery allocation coefficient in this embodiment. During the calculation of the dual-channel battery allocation coefficient, an initial allocation coefficient is calculated based on the battery capacity ratio, and then an allocation correction coefficient is calculated. Next, by determining the battery's operating mode, the final allocation coefficient is calculated based on the charging and discharging states, respectively. Finally, a limiting process is applied to ensure the limiting is within the range of [0, 1].

[0048] Figure 2 This is a flowchart illustrating a dual-battery grid-connected power distribution method for a hybrid inverter in one embodiment. It should be understood that, although... Figure 2 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows; unless explicitly stated otherwise, there is no strict order requirement for the execution of these steps, and they can be executed in other orders; and Figure 2At least some of the steps in the process may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least some of the sub-steps or stages of other steps.

[0049] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A method for power distribution in a hybrid inverter with dual-battery grid connection, characterized in that: The method includes: Determine the operating mode of the dual-battery system; If both batteries are in charging mode or both are in discharging mode, the final allocation coefficient of the two batteries is calculated based on their capacity and state of charge. The total system power limit is determined based on the operating mode of the dual-battery system. The power of the dual batteries is allocated according to the final allocation coefficient and the total power limit of the system.

2. The method according to claim 1, characterized in that: The calculation of the final allocation coefficient of the dual batteries based on their capacity and state of charge includes: Calculate the total effective capacity of the dual-battery system and determine whether the total effective capacity is greater than a preset capacity threshold. If the total effective capacity is greater than the preset capacity threshold, the initial allocation coefficient of the dual-battery is calculated, and the charge difference between the dual-battery is calculated. The allocation correction coefficient is calculated based on the charge difference value and the preset charge difference threshold; The final allocation coefficients of the dual-battery system are calculated based on the initial allocation coefficients and the allocation correction coefficients.

3. The method according to claim 2, characterized in that: The calculation of the initial allocation coefficients for the dual-battery system includes: ， ， in, Indicates the effective capacity of the first battery. Indicates the effective capacity of the second battery. This represents the initial allocation coefficient of the first battery. This represents the initial allocation coefficient of the second battery; The calculation of the charge difference between the two batteries includes: ， in, This indicates the state of charge of the first battery. This indicates the state of charge of the second battery. This indicates the charge difference between the two batteries.

4. The method according to claim 2, characterized in that: The calculation of the allocation correction coefficient based on the charge difference and the preset charge difference threshold includes: Determine whether the absolute value of the charge difference is less than a preset charge difference threshold; If the absolute value of the charge difference is less than the preset charge difference threshold, the allocation correction coefficient is set to 0; If the absolute value of the charge difference is not less than the preset charge difference threshold, then the product of the charge difference and the preset deviation ratio coefficient is set as the allocation correction coefficient.

5. The method according to claim 2, characterized in that: The step of calculating the final allocation coefficient of the dual-channel batteries based on the initial allocation coefficient and the allocation correction coefficient includes: Determine the operating mode of the dual-battery system; If both batteries are in charging mode, the final allocation coefficient for the two batteries is calculated as follows: ， ， in, This represents the final charging allocation coefficient of the first battery. This represents the final charging allocation factor for the second battery. This represents the initial allocation coefficient of the first battery. Indicates the allocation correction factor; If both batteries are in discharge mode, the final allocation coefficient for the two batteries is calculated as follows: ， ， in, This represents the final discharge distribution coefficient of the first battery. This represents the final discharge distribution coefficient of the second battery. This represents the initial allocation coefficient of the first battery. This represents the allocation correction factor.

6. The method according to claim 1, characterized in that: After calculating the final allocation coefficient of the dual batteries based on their capacity and state of charge, the method further includes: The final allocation coefficient is subjected to amplitude limiting processing, and the amplitude-limited final allocation coefficient is set as the amplitude-limited allocation coefficient; The process of allocating power to the dual batteries based on the final allocation coefficient and the total system power limit includes: The power of the dual batteries is allocated according to the limiting allocation coefficient and the total power limit of the system.

7. The method according to claim 6, characterized in that: The step of performing amplitude limiting processing on the final allocation coefficient and setting the amplitude-limited final allocation coefficient as the amplitude-limited allocation coefficient includes: Determine whether the final allocation coefficient is within the preset limit range; If the final allocation coefficient is within the preset limit range, then the final allocation coefficient is set as the limit allocation coefficient; If the final allocation coefficient is not within the preset limit range and is greater than the maximum value of the limit range, then the maximum value of the limit range is set as the limit allocation coefficient. If the final allocation coefficient is not within the preset limit range and is less than the minimum value of the limit range, then the minimum value of the limit range is set as the limit allocation coefficient.

8. The method according to claim 1, characterized in that: The determination of the system's total power limit based on the dual-battery operating mode includes: When both batteries are in charging mode, obtain the total power limit of system scheduling and the total power limit of dual battery charging. Compare the value of the total power limit for system scheduling with the value of the total power limit for dual-path battery charging, and set the maximum value as the total power limit for the system. When both batteries are in discharge mode, obtain the total power limit of system scheduling and the total power limit of dual battery discharge. Compare the total power limit of the system scheduling with the total power limit of the dual-path battery charging, and set the minimum value as the total power limit of the system.

9. The method according to claim 1, characterized in that: The dual-channel battery comprises two single-channel batteries; After allocating the power of the dual batteries according to the final allocation coefficient and the total system power limit, the method further includes: Set the power of the allocated dual batteries to the initial allocated power; Determine whether the initial power allocation of a single battery in the dual-battery system exceeds the maximum power limit of the corresponding battery. If no single battery has an initial power allocation exceeding the maximum power limit of the corresponding battery, then the initial power allocation of the dual batteries is the final power allocation of the dual batteries. If the initial power allocation of a single battery exceeds the maximum power limit of the corresponding battery, the power of the single battery exceeding the maximum power limit is clamped to the maximum power value of the battery, and the remaining power value is calculated. The remaining power value is compensated to another single-channel battery.

10. The method according to claim 2, characterized in that: Before determining whether the total effective capacity is greater than a preset capacity threshold, the method further includes: Determine whether the total effective capacity is 0; If the total effective capacity is not 0, then determine whether the total effective capacity is greater than a preset capacity threshold. If the total effective capacity is 0, then the total power limit of the system is set to 0.

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