Three-phase parallel operation system and power distribution method and device thereof

Abstract

The invention relates to the technical field of energy storage systems, and discloses a three-phase parallel operation system and a power distribution method and device thereof. The method comprises the following steps: acquiring initial distribution power of each phase of each energy storage inverter; determining a locked phase, a non-locked phase, a locked energy storage inverter and a non-locked energy storage inverter according to the initial distribution power of each phase of each energy storage inverter; determining missing power of the locked phase of the locked energy storage inverter according to the locked energy storage inverter and the locked phase; according to the initial distribution power of the non-locked phase of the locked energy storage inverter, the charging margin is obtained; according to the initial distribution power of the non-locking phase of the non-locking energy storage inverter, obtaining a discharge margin; and obtaining the target distribution power of each phase of each energy storage inverter according to the missing power, the charging margin and the discharging margin. Through overall calculation of the global margin, the problems that interphase power of a traditional parallel operation system is rigid and the overall performance is restricted by a single-point bottleneck are solved, and the load adaptability and the operation reliability of the parallel operation system are remarkably improved.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage systems, and in particular to a three-phase parallel system and a power distribution method and device thereof. Background Art

[0002] With the rapid development of the energy storage industry, especially the popularization of household energy storage products, more and more users have begun to rely on energy storage products to provide power for their own loads. Especially in the parallel mode, how to achieve load matching between energy storage inverters and ensure stable power supply to the load has become the key to technological development.

[0003] The existing technical solutions mainly include three load distribution methods for parallel systems: one is phase-by-phase sequential loading, that is, each inverter is connected to the load in sequence according to the phase sequence of the power system, so as to ensure balanced load distribution; the second is equal loading, that is, multiple inverters share the load and the power is evenly distributed; the third is proportional loading based on the state of charge (SOC) of the energy storage unit; these three solutions can optimize the discharge of the energy storage battery and the power output of the inverter to a certain extent, and improve the overall efficiency of the system. However, when the difference in the discharge capacity of the energy storage battery in the parallel system is too large, it will cause the system to be unable to fully match the load, which is still a challenge facing current technology. Summary of the invention

[0004] The implementation methods of the present application mainly solve the technical problem of how to reasonably and comprehensively distribute power to match the load.

[0005] In order to solve the above technical problems, a technical solution adopted in the implementation mode of the present application is: to provide a power distribution method for a three-phase parallel system, wherein the three-phase parallel system includes at least two energy storage inverters, and the method includes: obtaining the initial distribution power of each phase of each of the energy storage inverters; determining a locked phase and an unlocked phase according to the initial distribution power of each phase of each of the energy storage inverters; determining a locked energy storage inverter and an unlocked energy storage inverter according to the initial distribution power of each phase of each of the energy storage inverters and the discharge limit of the energy storage battery corresponding to each energy storage inverter ; According to the locked energy storage inverter and the locked phase, determine the missing power of the locked phase of the locked energy storage inverter; according to the initial allocation power of the non-locked phase of the locked energy storage inverter, obtain the charging margin; according to the initial allocation power of the non-locked phase of the non-locked energy storage inverter, obtain the discharging margin; according to the missing power, the charging margin and the discharging margin, obtain the target allocation power of each phase of each energy storage inverter; according to the target allocation power of each phase of each energy storage inverter, perform power output to match the load.

[0006] In some embodiments, determining a locked phase and an unlocked phase based on the initial allocated power of each phase of each energy storage inverter includes: obtaining each corresponding load power; calculating the total output power of each phase based on the initial allocated power of each phase of each energy storage inverter; comparing the total output power of each phase with the corresponding load power; defining the phase whose total output power is less than the corresponding load power as the locked phase; otherwise, it is the unlocked phase.

[0007] In some embodiments, the locked energy storage inverter and the non-locked energy storage inverter are determined according to the initial allocated power of each phase of each energy storage inverter and the discharge limit of the energy storage battery corresponding to each energy storage inverter, including: calculating the three-phase total output power of each energy storage inverter according to the initial allocated power of each phase of each energy storage inverter; defining the energy storage inverter whose three-phase total output power is equal to the discharge limit of the energy storage battery as a locked energy storage inverter; and defining the energy storage inverter whose three-phase total output power is less than the discharge limit of the energy storage battery as a non-locked energy storage inverter.

[0008] In some embodiments, determining the missing power of the locked phase of the locked energy storage inverter based on the locked energy storage inverter and the locked phase includes: obtaining the sum of the initially allocated powers of the non-locked energy storage inverters in the locked phase; the difference between the load power corresponding to the locking and the sum of the initially allocated powers of the non-locked energy storage inverters in the locked phase is the sum of the missing powers; determining the missing power of the locked phase of each locked energy storage inverter based on the sum of the missing powers, the number of the locked energy storage inverters and the maximum allowable discharge power.

[0009] In some embodiments, obtaining the charging margin according to the initial allocated power of the non-locked phase of the locked energy storage inverter includes: determining whether the initial allocated power of the non-locked phase in the locked energy storage inverter is zero; if the initial allocated power of the non-locked phase is not zero, it indicates that the non-locked phase is used to power the load, and it is determined that the non-locked phase cannot be charged; if the initial allocated power of the non-locked phase is zero, it indicates that the non-locked phase is not used to power the load, and it is determined that the non-locked phase is a chargeable phase; and obtaining the maximum allowable charging power of the chargeable phase in the locked energy storage inverter as the charging margin.

[0010] In some embodiments, the method of obtaining the discharge margin according to the initial allocated power of the non-locked phase of the non-locked energy storage inverter includes: obtaining the discharge limit of the energy storage battery corresponding to the non-locked energy storage inverter and the maximum allowable discharge power of the non-locked phase of the non-locked energy storage inverter; and calculating the discharge margin according to the discharge limit of the energy storage battery corresponding to the non-locked energy storage inverter, the maximum allowable discharge power of the non-locked phase of the non-locked energy storage inverter and the initial allocated power.

[0011] In some embodiments, the target allocated power of each phase of each energy storage inverter is obtained according to the missing power, the charging margin and the discharging margin, including: determining the non-locked phase for power scheduling in the non-locked energy storage inverter according to the discharging margin and the missing power, and obtaining the first scheduling power of the non-locked phase for power scheduling in the non-locked energy storage inverter; determining the non-locked phase for power scheduling in the locked energy storage inverter according to the charging margin and the missing power, and obtaining the second scheduling power of the non-locked phase for power scheduling in the locked energy storage inverter; obtaining the target allocated power of each phase of each energy storage inverter according to the missing power, the first scheduling power and the second scheduling power.

[0012] In some embodiments, determining the non-locked phase for the power scheduling in the locked energy storage inverter based on the charging margin and the missing power, and obtaining the second scheduling power of the non-locked phase for the power scheduling in the locked energy storage inverter, includes: obtaining the load power corresponding to the non-locked phase for the power scheduling in the locked energy storage inverter and the discharge limit of the energy storage battery corresponding to the non-locked energy storage inverter; obtaining the second scheduling power according to the first scheduling power, the load power and the discharge limit of the energy storage battery.

[0013] In order to solve the above technical problems, another technical solution adopted in the embodiment of the present application is: to provide a power distribution device for a three-phase parallel system, wherein the three-phase parallel system includes at least two energy storage inverters, and the device includes: an acquisition module, wherein the acquisition module is used to acquire the initial distribution power of each phase of each of the energy storage inverters; a first confirmation module, wherein the first confirmation module is used to determine the locked phase and the non-locked phase according to the initial distribution power of each phase of each of the energy storage inverters; a second confirmation module, wherein the second confirmation module is used to determine the locked energy storage inverter and the non-locked energy storage inverter according to the initial distribution power of each phase of each of the energy storage inverters and the discharge limit of the energy storage battery corresponding to each energy storage inverter; a missing power calculation module, wherein the missing power calculation module is used to determine the locked energy storage inverter and the non-locked energy storage inverter according to the initial distribution power of each phase of each of the energy storage inverters and the discharge limit of the energy storage battery corresponding to each energy storage inverter; and a missing power calculation module, wherein the missing power calculation module is used to determine the locked energy storage inverter and the non-locked energy storage inverter according to the initial distribution power of each phase of each of the energy storage inverters and the discharge limit of the energy storage battery corresponding to each energy storage inverter. Lock the energy storage inverter and the locked phase, determine the missing power of the locked phase of the locked energy storage inverter; a charging remainder calculation module, the charging remainder calculation module is used to obtain the charging remainder according to the initial allocation power of the non-locked phase of the locked energy storage inverter; a discharging remainder calculation module, the discharging remainder calculation module is used to obtain the discharging remainder according to the initial allocation power of the non-locked phase of the non-locked energy storage inverter; a power scheduling calculation module, the power scheduling calculation module is used to obtain the target allocation power of each phase of each energy storage inverter according to the missing power, the charging remainder and the discharging remainder; a power distribution module, the power distribution module is used to output power to match the load according to the target allocation power of each phase of each energy storage inverter.

[0014] To solve the above technical problems, another technical solution adopted in the implementation mode of the present application is: to provide a three-phase parallel system, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method described above.

[0015] Different from the related art, the present application provides a three-phase parallel system and its power distribution method and device. 1. Adopting the multi-stage progressive calculation process of "initial distribution → locked phase / locked energy storage inverter → surplus redistribution", by real-time acquisition of key parameters such as load power, charging margin, discharge margin and missing power of each phase, combined with a dynamic adjustment mechanism, overcome the limitation that traditional single-step distribution is difficult to cope with multi-phase load changes. 2. Based on the initial power distribution, the locked phase is obtained in combination with the load power, and the locked energy storage inverter is screened in combination with the discharge limit of the energy storage battery to achieve accurate positioning of the system bottleneck and provide a decision-making basis for subsequent cross-phase compensation. 3. Propose the joint calculation of the charging margin (the remaining amount of the non-locked phase of the locked energy storage inverter) and the discharging margin (the additional power of the non-locked inverter), and compensate for the missing power of the locked phase through surplus redistribution, breaking through the limitation of traditional independent allocation of the same phase, allowing the energy storage inverter to dynamically allocate power between different phases, and realizing energy interaction between the three phases. 4. Through the overall calculation of global margin, the cross-phase power is coordinated and dispatched among multiple energy storage inverters to avoid single-machine overload while maximizing the overall load capacity of the system. This solves the problems of rigid inter-phase power and single-point bottleneck restricting the overall performance of the traditional parallel system, and significantly improves the load adaptability and operation reliability of the parallel system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] One or more embodiments are exemplarily described by corresponding drawings, which do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and the figures in the drawings do not constitute proportional limitations unless otherwise stated.

[0017] Figure 1 It is a structural schematic block diagram of a three-phase parallel system provided in an embodiment of the present application; Figure 2 is a flow chart of a power distribution method for a three-phase parallel system provided in an embodiment of the present application; Figure 3 is a flow chart of a target power allocation calculation process provided by an embodiment of the present application; Figure 4 It is a schematic block diagram of the structure of a power distribution device for a three-phase parallel system provided in an embodiment of the present application; Figure 5 It is a hardware structure diagram of a three-phase parallel system for executing a power distribution method for a three-phase parallel system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0019] It should be noted that, if there is no conflict, the various features in the embodiments of the present application can be combined with each other, all within the scope of protection of the present application. In addition, although the functional modules are divided in the device schematic diagram and the logical order is shown in the flow chart, in some cases, the steps shown or described can be performed in a different order than the module division in the device schematic diagram or the order in the flow chart.

[0020] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0021] See also Figure 1 , Figure 1 1 is a schematic block diagram of a three-phase parallel system provided in an embodiment of the present application. Figure 1 As shown, the three-phase parallel system 100 includes multiple stand-alone systems 10, each of which is a standardized three-phase energy storage system that integrates energy storage batteries and energy storage inverters. Each subsystem achieves plug-and-play expansion capabilities through modular design. The AC side of the energy storage inverter of each stand-alone system uses low-impedance parallel technology to access the common bus to form a multi-machine parallel power supply network, which is synchronously connected to the load end and the grid access point. Each stand-alone system 10 establishes a real-time data exchange link with the superior energy management system (EMS) and the grid dispatching center through the power carrier and CAN bus dual-mode communication channel to achieve energy storage battery SOC status detection, inverter operation parameter synchronization, and dynamic perception of grid / load demand.

[0022] In this embodiment, the three-phase parallel system 100 includes at least two parallel stand-alone systems 10, and the stand-alone system is specifically a three-phase energy storage system. Among them, the energy storage inverter converts direct current (DC) into alternating current (AC), and converts alternating current into direct current. Each energy storage inverter can control the voltage and power output of each phase, and adjust the charging and discharging state according to the needs of the energy storage battery. Each phase of each inverter has a corresponding maximum allowable charge / discharge power, which is mainly limited by the inverter hardware itself, such as the rated parameters of the power device; when the inverter models are the same, the maximum allowable charge / discharge power of each phase of each inverter is the same. Each energy storage battery may include multiple energy storage batteries, and each energy storage battery has different discharge power limits and charging power limits according to its SOC value.

[0023] The three-phase parallel system 100 has three core operating modes: energy storage priority mode, hybrid power supply mode and grid charging mode. When the energy storage battery of the three-phase parallel system 100 has sufficient energy, it adopts the energy storage priority mode, and the parallel system fully bears the load power supply. The power grid plays an important auxiliary role in the three-phase parallel system 100, especially when the load demand exceeds the discharge capacity of the three-phase parallel system 100, the power grid provides an additional source of power, and the three-phase parallel system 100 adopts a hybrid power supply mode. When the energy storage battery is insufficient, the three-phase parallel system 100 automatically switches to the grid charging mode, and the grid provides power to the energy storage inverter to charge the battery, and the load is directly supplied by the grid; after the inverter obtains AC power from the grid, it converts it into DC power and charges it into the battery to ensure that the energy storage system has enough power to cope with future load demands.

[0024] The power grid cooperates with the three-phase parallel system 100 to ensure a stable supply of load power. Through the power dispatch algorithm, the power grid can supplement the shortage of the energy storage system when necessary, or when the output of the energy storage system exceeds the load, the power grid can absorb excess power to prevent power waste.

[0025] In a parallel system, load matching can usually be done by sequential or equal matching of the inverters, provided that the total discharge limit of the BMS (Battery Management System) allows this approach. However, in some special cases, although the total discharge limit of the BMS of the parallel system is large enough to theoretically match the load demand, the discharge SOP (State of power) of each energy storage battery in the system varies greatly, resulting in the inability to fully utilize the discharge capacity of all energy storage batteries, and thus the inability to fully meet the load demand. At this time, even if the total discharge limit is not exceeded, the discharge capacity of some energy storage batteries in the system is limited, so that some loads still need to be supplemented by the grid. This situation is common in systems with uneven energy storage battery capacity (SOC) or large differences in discharge efficiency, requiring the grid to provide additional support during peak load periods. Ideally, users or R&D personnel hope that when the system's discharge power allows, the load should be fully powered by the parallel system.

[0026] To do this, see Figure 2 , Figure 2 1 is a flow chart of a power distribution method for a three-phase parallel system provided in an embodiment of the present application. Figure 2 As shown, the method is applied to the above-mentioned three-phase parallel system 100, and the method includes steps S101-S108: S101: Obtaining the initial distribution power of each phase of each energy storage inverter.

[0027] First, it is necessary to identify all the energy storage inverters participating in the grid connection in the parallel system. These energy storage inverters are usually three-phase inverters that can output three-phase AC power, and each inverter can allocate power to different phases (L1 phase, L2 phase, and L3 phase). In this step, it is necessary to determine the basic information of these inverters, including their numbers, rated power, current load, status, and their power output capacity for each phase.

[0028] Secondly, in order to obtain accurate initial power distribution, it is necessary to monitor the real-time working status of each energy storage inverter, including the following aspects: Load information: obtain the current load power of each phase of each inverter. For example, the load power corresponding to phases L1, L2, and L3 of inverter A. Discharge state: The discharge state of the inverter is the discharge capacity of the energy storage battery. If the inverter is charging, the discharge power is zero; if it is discharging, the output power of each phase of the inverter is recorded. Battery management system (BMS) information: Obtain information such as the battery's state of health (SOH), battery remaining capacity (SOC), and charge / discharge power limit through the BMS, which helps calculate the target output power of each phase of each inverter.

[0029] Thirdly, each energy storage inverter will have a preliminary power allocation, which is called the initial power allocation before the secondary power scheduling. Specifically, the initial power allocation refers to the power initially allocated to each phase of each inverter before the optimization scheduling is performed based on the current energy storage battery status, load demand, and the maximum allowable charge / discharge power of the inverter. The initial power allocation can be allocated according to existing phase-by-phase sequential loading, equal loading, SOC-based proportional loading and other strategies.

[0030] The key to this step is to monitor and collect the load power of each phase, battery status (battery charging limit and discharge limit), and the maximum allowable charge / discharge power of the inverter in real time, and then perform the initial power allocation. By accurately obtaining the initial allocated power, it lays the foundation for subsequent power scheduling, missing power calculation, and evaluation of charging margin and discharge margin.

[0031] S102: Determine a locked phase and an unlocked phase according to the initial distribution power of each phase of each energy storage inverter.

[0032] According to the initial distribution power of each phase of each energy storage inverter, the locked phase and the unlocked phase are determined, including: obtaining the corresponding load power; calculating the total output power of each phase according to the initial distribution power of each phase of each energy storage inverter; comparing the total output power of each phase with the corresponding load power; defining the phase whose total output power is less than the corresponding load power as a locked phase; otherwise, it is an unlocked phase.

[0033] In order to determine the locked phase, it is first necessary to obtain the load power corresponding to each phase (L1 phase, L2 phase, L3 phase). These load power values ​​are usually determined by the system load requirements or external load conditions. Each load power represents the total power demand that the energy storage inverter needs to provide for each phase. For example, assuming that the load power of the L1 phase is 4 kW, this means that the total power demand of the L1 phase of the energy storage inverter is 4 kW.

[0034] Secondly, the initial power allocation of each phase of each energy storage inverter is obtained. It can be understood that the initial power allocation of each phase of each energy storage inverter refers to the power allocated by the inverter according to the currently set allocation strategy. The initial power allocation of each inverter depends on the battery status, load demand and output capacity of the inverter.

[0035] Again, calculate the total output power of each phase. It can be understood that the total output power of each phase is calculated as the sum of the power allocated by each inverter on that phase. For example, for phase L1, assuming there are two inverters, the initial power allocated by inverter A on phase L1 is 2 kW, and the initial power allocated by inverter B on phase L1 is 2 kW, then the total output power of phase L1 is 4 kW.

[0036] Next, compare the total output power of each phase with the load power. It can be understood that the total output power of each phase is compared with the corresponding load power. The comparison results are as follows: If the total output power of a phase is less than the load power, it means that the phase cannot meet the load demand and is a "locked phase" and needs to enter the locked state. If the total output power of a phase is greater than or equal to the load power, the phase can meet the load demand and is regarded as a "non-locked phase". For example, assuming that the load power of phase L1 is 4kW and the total output power of phase L1 is 4 kW, then phase L1 is a non-locked phase because its output power meets the load demand. If the load power of phase L1 is 4 kW, but the total output power of phase L1 is 3 kW, then phase L1 is a locked phase.

[0037] Finally, the locked phase is determined and the locked phase flag is output. It can be understood that by comparing the total output power and load power of each phase, the locked phase and the unlocked phase can be obtained: if the total output power of a phase is less than the load power, the phase is a locked phase. For example, if the total output power of the L1 phase is 3 kW and the load power is 4 kW, the L1 phase is marked as a locked phase (lockphase[1] = 1). Conversely, if the total output power of a phase is greater than or equal to the load power, it is an unlocked phase. In practical applications, this comparison process can be implemented by programming to automatically check and set the locking status of each phase. Finally, the system outputs the locking status of each phase. The purpose of marking the locked phase is to make corresponding power adjustments in subsequent power scheduling. The locked phase needs to borrow power from the unlocked phases of other inverters to balance the load demand.

[0038] This embodiment can accurately identify which phases cannot meet the load demand by accurately calculating the total output power of each phase and comparing it with the corresponding load power, thereby determining the locked phase. Through the identification of the locked phase, the system can perform targeted power scheduling, so that the phase that cannot meet the load can borrow the power of other phases, avoiding the degradation of the overall system performance due to local power shortage, and improving the load adaptation capability and efficiency of the three-phase parallel system.

[0039] S103: Determine a locked energy storage inverter and a non-locked energy storage inverter according to the initial distribution power of each phase of each energy storage inverter and the discharge limit of the energy storage battery corresponding to each energy storage inverter.

[0040] According to the initial allocated power of each phase of each energy storage inverter and the discharge limit of the energy storage battery corresponding to each energy storage inverter, the locked energy storage inverter and the non-locked energy storage inverter are determined, including: calculating the three-phase total output power of each energy storage inverter according to the initial allocated power of each phase of each energy storage inverter; defining the energy storage inverter whose three-phase total output power is less than the discharge limit of the energy storage battery as a non-locked energy storage inverter, otherwise, it is a locked energy storage inverter.

[0041] First, based on the initial distribution power of each phase of each energy storage inverter, the three-phase total output power of each energy storage inverter is calculated. In step S101, the initial distribution power data of each phase of all energy storage inverters has been obtained. For example, the initial distribution power of energy storage inverter A in phase L1 is 2 kW, the initial distribution power in phase L2 is 0 kW, and the initial distribution power in phase L3 is 2 kW, then the three-phase total output power of energy storage inverter A is 4 kW.

[0042] Secondly, obtain the discharge limit of the energy storage battery corresponding to each energy storage inverter. The discharge limit of the energy storage battery indicates the maximum power or energy that the battery can provide from the stored electrical energy. The discharge limit of the energy storage battery is generally related to the battery SOC, battery temperature, battery SOH, etc.; the BMS (battery management system) of the energy storage battery will automatically calculate the corresponding discharge limit based on the above influencing factors. Usually at low SOC, the BMS will actively limit the discharge current, and the discharge (power) limit will become smaller; at medium and high SOC, its discharge (power) limit can usually reach the nominal value; at high SOC, the upper limit of the discharge (power) limit is not limited by the SOC, but the charging (power) limit will be reduced. At low battery temperature (such as <0℃) and high battery temperature (such as >45℃), the discharge power will be forced to be reduced, that is, the discharge limit will be reduced. The lower the SOH, the lower the discharge limit.

[0043] Again, compare the three-phase total output power of each energy storage inverter with the discharge limit of the corresponding energy storage battery. The energy storage inverter whose three-phase total output power is equal to the discharge limit of the energy storage battery is defined as a locked energy storage inverter; the energy storage inverter whose three-phase total output power is less than the discharge limit of the energy storage battery is defined as a non-locked energy storage inverter. It can be understood that by comparing the three-phase total output power of each energy storage inverter with the discharge limit of the corresponding energy storage battery, it can be determined which energy storage batteries still have surplus power (remaining available power) and which energy storage batteries have exhausted their power due to insufficient energy. The specific operation is as follows: If the three-phase total output power of a certain energy storage inverter is equal to the discharge limit of the corresponding energy storage battery, the energy storage inverter can no longer provide excess power and is marked as a locked energy storage inverter. If the three-phase total output power of the energy storage inverter is less than the discharge limit of the corresponding energy storage battery, the energy storage inverter can still provide surplus power and is marked as a non-locked energy storage inverter. For example, for the above-mentioned energy storage inverter A, the initial allocated powers of its L1 phase, L2 phase, and L3 phase are 2 kW, 0 kW, and 2 kW respectively; when the discharge limit of the energy storage battery is 4 kW, the energy storage inverter A is marked as a locked energy storage inverter; when the discharge limit of the energy storage battery is 6kW, the energy storage inverter A is marked as a non-locked energy storage inverter. Finally, the system will output which energy storage inverters are marked as locked energy storage inverters and which energy storage inverters are marked as non-locked energy storage inverters based on the above power comparison. These locked energy storage inverters require special treatment in subsequent power scheduling, and the load demand needs to be met by borrowing the power of non-locked energy storage inverters.

[0044] This embodiment effectively identifies which energy storage inverters still have surplus power and which energy storage inverters have exhausted their power by comparing the three-phase total output power of each energy storage inverter with the discharge limit of the corresponding energy storage battery. By clearly marking locked energy storage inverters and non-locked energy storage inverters, the system can adjust the power allocation strategy in time and lock the inverters that have exhausted their power allocation, ensuring that the three-phase total power output of the energy storage inverter does not exceed the maximum discharge capacity of the corresponding energy storage battery, preventing overload and battery loss, and ensuring that the entire parallel system can operate smoothly and stably, improving the safety and efficiency of the system.

[0045] S104: Determine the missing power of the locked phase of the locked energy storage inverter according to the locked energy storage inverter and the locked phase.

[0046] According to the locked energy storage inverter and the locked phase, the missing power of the locked phase of the locked energy storage inverter is determined, including: obtaining the sum of the initial allocated powers of the non-locked energy storage inverters in the locked phase; the difference between the load power corresponding to the lock and the sum of the initial allocated powers of the non-locked energy storage inverters in the locked phase is the sum of the missing powers; according to the sum of the missing powers, the number of locked energy storage inverters and the maximum allowable discharge power, the missing power of the locked phase of each locked energy storage inverter is determined.

[0047] First, obtain the sum of the initial allocated powers of the non-locked energy storage inverters in the locked phase. It is understandable that in the locked phase, the system needs to identify which energy storage inverters are marked as non-locked energy storage inverters. Then, obtain the initial allocated powers of these non-locked energy storage inverters in the locked phase and add them up. For example, L1 phase is a locked phase, energy storage inverter B is a locked inverter, energy storage inverter A is a non-locked energy storage inverter, and energy storage inverter C is a non-locked energy storage inverter. Assuming that in L1 phase, the initial allocated power of inverter A is 1 kW and the initial allocated power of inverter C is 2 kW, the sum of the initial allocated powers of non-energy storage inverters in the locked phase is 3 kW.

[0048] Next, calculate the sum of missing power. The sum of missing power is the difference between the total power required by the load and the power provided by the non-locked inverter. For example, if the load power of phase L1 is 5 kW and the sum of the initial distribution power of the non-locked energy storage inverter is 3 kW, the sum of missing power is 2 kW.

[0049] Again, the missing power is distributed in order / equal distribution / proportional / unfixed ratio. It can be understood that according to the sum of the missing power of the locked phases, the system needs to reasonably distribute the power to all locked energy storage inverters. This process can be distributed in the following ways: Equal distribution method: The sum of missing power is evenly distributed to all locked energy storage inverters. The power allocated to each locked energy storage inverter is:

[0050] For example, assuming the sum of missing power is 2 kW and there are two locked energy storage inverters, the shared power is 1 kW.

[0051] Sequential allocation method: According to certain sequence rules, the missing power is allocated to each locked energy storage inverter. For example, the missing power can be allocated according to factors such as the output capacity of the inverter, load priority, etc. If the maximum allowable discharge power of each locked energy storage inverter is different, the inverter with smaller power can be allocated first until the maximum discharge power limit of the inverter is reached, and then continue to allocate to the next inverter until the missing power is completely allocated.

[0052] Proportional allocation method: According to the unused margin of each locked energy storage inverter in the locked phase, the missing power is allocated to each locked energy storage inverter in a certain proportion.

[0053] For each energy storage inverter, the maximum allowable discharge power of each phase is generally obtained based on the parameters of the power device of the energy storage inverter, which indicates the maximum power that the energy storage inverter can output safely and stably. When the inverter models are the same, the maximum allowable discharge power of each phase of each inverter is generally the same.

[0054] The unused margin of each locked energy storage inverter in the locked phase refers to the difference between the maximum allowable discharge power and the initial distribution power.

[0055] For example, assuming that the locked phase is L3, inverter A is a non-locked energy storage inverter, inverter B and inverter C are both locked energy storage inverters, the initial allocated power of L3 phase of inverter B is 1 kW, the initial allocated power of L3 phase of inverter C is 0 kW, the sum of the missing power is 4 kW, and the maximum allowable discharge power of each phase of each energy storage inverter is 3 kW; then the unused margin of inverter B is 2 kW, and the unused margin of inverter C is 3 kW. The missing power of inverter B is proportionally distributed as 2 / (2+3)*4=1.6 kW, and the missing power of inverter C is proportionally distributed as 3 / (2+3)*4=2.4 kW.

[0056] Unfixed quota allocation method: allocation is not based on any fixed standard, but can be flexibly allocated according to actual conditions and different combinations of factors. Using the example of the proportional allocation method, for example, the missing power of inverter B can be allocated to 1.8 kW, and the missing power of inverter C can be allocated to 2.2 kW.

[0057] It is understandable that no matter whether the equal distribution method, sequential distribution method, proportional distribution method or variable quota distribution method is adopted, it is necessary to ensure that the sum of the missing power and the initial distribution power of each locked energy storage inverter does not exceed its maximum allowable discharge power. This is to prevent overload operation and protect the safety of energy storage batteries and energy storage inverters. If the calculated missing power exceeds the maximum allowable discharge power of a certain inverter, the inverter can only be allocated the maximum allowable discharge power. For example, according to the equal distribution method, the actual distribution can be limited by the following formula: ; in, is the maximum allowable discharge power of each energy storage inverter; It is the initial distribution power of the locked phase of each energy storage inverter.

[0058] Finally, according to the above allocation strategy, the missing power of each locked energy storage inverter is output as the basis for subsequent power scheduling. These inverters will output according to the calculated missing power until the load power is fully met as much as possible.

[0059] This embodiment ensures that each inverter provides the required power within its maximum allowable discharge power range by reasonably distributing and locking the missing power of the energy storage inverter. This not only helps balance the power output of each energy storage inverter in the system and avoids inverter overload, but also optimizes power dispatch efficiency and ensures that the entire parallel system can stably and smoothly provide the required power to the load.

[0060] S105: Obtain the charging margin according to the initial distribution power of the non-locked phase of the locked energy storage inverter.

[0061] The charging margin is obtained according to the initial allocated power of the non-locked phase of the locked energy storage inverter, including: judging whether the initial allocated power of the non-locked phase in the locked energy storage inverter is zero; if the initial allocated power of a non-locked phase is not zero, it indicates that the non-locked phase is used to power the load, and it is determined that the non-locked phase cannot be charged; if the initial allocated power of a non-locked phase is zero, it indicates that the non-locked phase is not used to power the load, and it is determined that the non-locked phase is a chargeable phase; and the maximum allowable charging power of the chargeable phase in the locked energy storage inverter is obtained as the charging margin.

[0062] First, the system needs to determine whether the initial allocated power of the non-locked phase in the locked energy storage inverter is zero. Specifically, for each locked energy storage inverter, check its initial allocated power in the non-locked phase. If the power value is not zero, it means that the non-locked phase has been used to provide power to the load; if the initial allocated power is zero, it means that the non-locked phase is not powered by the load, so it can be used for charging. It can be understood that if the initial allocated power is not zero, it means that the non-locked phase has been used to power the load, so the phase cannot be charged, and the charging margin is zero in this case. If the initial allocated power is zero, it means that the non-locked phase is not used to power supply, so the phase is considered to be a rechargeable phase. At this point, the system can proceed to the next step to calculate the charging margin.

[0063] Secondly, for each locked energy storage inverter, the maximum allowable charging power of the chargeable phase is obtained. The maximum allowable charging power is generally obtained based on the parameters of the power device of the energy storage inverter, which indicates the maximum power that the energy storage inverter can input safely and stably. When the inverter models are the same, the maximum allowable charging power of each phase of each inverter is generally the same.

[0064] Finally, after determining the chargeable phase, the system can calculate the charge margin based on the maximum allowable charging power of the chargeable phase. The charge margin refers to how much power the non-locked phase can provide for charging under the current load demand. The calculation formula is: charge margin = maximum allowable charging power - initial allocation power.

[0065] Since the initial allocated power of the rechargeable phase is 0, the charging remainder of the rechargeable box is equal to the maximum allowable charging power, that is: charging remainder = maximum allowable charging power.

[0066] For example, if the maximum permissible charging power is 2 kW, the charging margin is 2 kW.

[0067] Finally, according to the above calculation, the charging margin is output. This information will serve as the basis for subsequent power scheduling and be used to coordinate the work of other inverters in the system to ensure that the energy storage inverter can charge or discharge as required.

[0068] This embodiment determines whether the inverter has charging capability by identifying which non-locked phases of the inverter are not used to power the load, and calculates the remaining charge. This provides an important basis for the power scheduling of the system, ensuring a balance between load demand and charging demand, thereby efficiently utilizing the working capacity of each inverter. By properly arranging charging and discharging, the working efficiency of the energy storage system can be maximized, energy utilization can be optimized, over-discharging or over-charging can be prevented, and the reliability and endurance of the system can be enhanced.

[0069] S106: Obtaining a discharge margin according to the initial distribution power of the non-locked phase of the non-locked energy storage inverter.

[0070] According to the initial allocated power of the non-locked phase of the non-locked energy storage inverter, the discharge margin is obtained, including: obtaining the discharge limit of the energy storage battery corresponding to the non-locked energy storage inverter and the maximum allowable discharge power of the non-locked phase of the non-locked energy storage inverter; according to the discharge limit of the energy storage battery corresponding to the non-locked energy storage inverter, the maximum allowable discharge power of the non-locked phase of the non-locked energy storage inverter and the initial allocated power, the discharge margin is calculated.

[0071] First, it is necessary to obtain the discharge limit value of the energy storage battery corresponding to the non-locked energy storage inverter.

[0072] Secondly, the maximum allowable discharge power of the non-locked phase of the non-locked energy storage inverter is obtained.

[0073] Again, the initial distribution power of the non-locked phase of the non-locked energy storage inverter is obtained.

[0074] Finally, according to the above parameters, the discharge margin is calculated. The calculation formula of the discharge margin is as follows:

[0075] in, is the maximum allowable discharge power of the non-locked phase, is the initial power distribution of the non-locked phase, is the discharge limit of the energy storage battery corresponding to the inverter, It is the sum of the initial distributed power of each phase.

[0076] Through this formula, the system takes into account the maximum allowable discharge power of each phase, the initial distribution power and the discharge limit of the energy storage battery to obtain the available discharge margin of the non-locked inverter.

[0077] For example, taking inverter A as an example, L3 phase is the locked phase, and the initial power distribution of L3 phase is 2kW. Assume The maximum allowable discharge power of L1 or L2 phase is 3kW (the maximum allowable discharge power of L1 or L2 phase), the initial distribution power of L1 phase is 2kW, the initial distribution power of L2 phase is 1kW, and the discharge limit of the energy storage battery is 6kW. According to the formula, for L1 phase, the discharge margin is min{3-2, 6-(2+1+2)}=1kW. For L2 phase, the discharge margin is min{3-1, 6-(2+1+2)}=1kW.

[0078] This embodiment comprehensively considers the maximum allowable discharge capacity of each inverter at different phases, the discharge limit of the energy storage battery, and the initial power allocation, so as to reasonably calculate the discharge margin. This can ensure that the non-locked energy storage inverter has sufficient available power to meet the system requirements, avoid power shortages due to the discharge limit of the energy storage battery, and avoid excessive discharge of the system or damage to the safety of the battery. In addition, by ensuring reasonable power allocation, the load of the inverter can be effectively balanced, energy management can be optimized, and the overall operating efficiency and stability of the system can be improved.

[0079] S107: Obtain the target allocated power of each phase of each energy storage inverter according to the missing power, the charging margin and the discharging margin.

[0080] See also Figure 3 , Figure 3 : is a flow chart of a target power allocation calculation process provided by an embodiment of the present application. Figure 3 As shown, according to the missing power, the charging margin and the discharging margin, the target allocated power of each phase of each energy storage inverter is obtained, including steps S1071-S1073: S1071: Determine a non-locked phase for power scheduling in the non-locked energy storage inverter according to the discharge margin and the missing power, and obtain a first scheduling power of the non-locked phase for power scheduling in the non-locked energy storage inverter.

[0081] First, the missing power of the locked phase of the locked energy storage inverter can be obtained by the above step S104, which is recorded as . Secondly, the discharge margin of the non-locked energy storage inverter can be obtained from step S106 to determine which phases can provide power. Select the phase that can provide discharge power, record it as the first scheduling phase, and ensure that the discharge margin of this phase is greater than or equal to the missing power. Finally, calculate the first scheduling power. It can be understood that assuming the discharge margin of the first scheduling phase is , then the first dispatch power The calculation formula is:

[0082] In addition, it is also necessary to ensure that after power scheduling and allocation, the sum of the allocated power of each phase of the energy storage inverter does not exceed the total battery discharge limit of the energy storage inverter (that is, the discharge limit of the energy storage battery corresponding to the above energy storage inverter), that is:

[0083] For example, taking two energy storage inverters as an example, assuming that the L3 phase of the locked energy storage inverter B is a locked phase, and the missing power is 1kW, the discharge margins of the L1 and L2 phases of the non-locked energy storage inverter A are 0kW and 2kW, that is, the L2 phase of the non-locked energy storage inverter A is determined to be the phase that can be used for power scheduling. According to the above formula, the first scheduling power can be obtained as 1kW, that is, the L2 phase of the non-locked energy storage inverter A will allocate 1kW power for power scheduling. In addition, when the discharge margins of the L1 and L2 phases of the non-locked energy storage inverter A are 1kW and 2kW, combined with the missing power, it can be obtained that the L1 phase is determined to be used for power scheduling at this time. It can be understood that while ensuring that the discharge margin of the non-locked phase is greater than or equal to the missing power, the non-locked phase corresponding to the minimum discharge margin can also be selected for power scheduling while meeting the power scheduling requirements. Finally, after redistributing the power, it is also required that the sum of the allocated power of each phase of the energy storage inverter does not exceed the total battery discharge limit of the energy storage inverter. It can be understood that, for example, after the secondary power distribution, the corresponding powers of L1, L2 and L3 of the non-locked inverter A are 2kW, 1kW, 2kW, and the total battery discharge limit of the non-locked inverter A is 6 kW. According to the above formula, the total battery discharge limit condition is also met after the secondary power distribution, that is, the first power scheduling is reasonable.

[0084] S1072: Determine the non-locked phase for power scheduling in the locked energy storage inverter according to the charge margin and the missing power, and obtain the second scheduling power of the non-locked phase for power scheduling in the locked energy storage inverter.

[0085] According to the charge margin and the missing power, a non-locked phase for power scheduling in the locked energy storage inverter is determined, and a second scheduling power of the non-locked phase for power scheduling in the locked energy storage inverter is obtained, including: obtaining the load power corresponding to the non-locked phase for power scheduling in the locked energy storage inverter and the discharge limit of the energy storage battery corresponding to the non-locked energy storage inverter; and obtaining the second scheduling power according to the first scheduling power, the load power and the discharge limit of the energy storage battery.

[0086] First, the non-locked phase and the first dispatching power for power dispatching can be known from the above step S1071. On this basis, the charging margin of the locked energy storage inverter is obtained from step S105, and which phases can be used for charging are determined, and the chargeable phase is selected and recorded as the second dispatching phase.

[0087] Secondly, calculate the second dispatch power. It is understandable that when performing the second dispatch power, it is necessary to ensure the overall power balance of the second dispatch phase. Among them, the second dispatch power calculation formula is as follows: ; In addition, it is also necessary to ensure that after power scheduling and allocation, the sum of the allocated power of each phase of the energy storage inverter does not exceed the total battery discharge limit of the energy storage inverter (the discharge limit of the energy storage battery corresponding to the above energy storage inverter), that is:

[0088] Furthermore, it is also necessary to ensure that the overall power of the second scheduling phase meets the corresponding load power demand.

[0089] For example, taking step S1071 as an example, it is known that the corresponding powers of the non-locked inverter A after the secondary power distribution are 2kW, 1 kW and 2 kW. Assuming that the load power of the L2 phase is 0 kW, the total battery discharge limit of the locked inverter B is 2kW, and the corresponding powers of the non-locked phase of the locked inverter B after the initial power distribution are 2kW and 0 kW, the charging margin of the non-locked phase (L2 phase) of the locked inverter B is 2 kW, and the corresponding load power of L2 is 0kW. According to the above formula, the second dispatching power of the L2 phase of the locked inverter B is -1kW. At this time, it is also necessary to determine whether the sum of the power of each phase of the locked inverter B does not exceed the total battery discharge limit of the energy storage inverter, that is, (2+(-1)+1)=2. In addition, it is necessary to calculate whether the overall power of the second dispatching phase meets its corresponding load power demand, that is, 1+(-1)=0. Based on this, the second power dispatch is reasonable.

[0090] S1073: Obtain the target allocated power of each phase of each energy storage inverter according to the missing power, the first dispatching power, and the second dispatching power.

[0091] It is understandable that after obtaining the missing power, the first dispatching power and the second dispatching power, the first dispatching phase for power dispatching, the second dispatching phase for power dispatching and the phase for borrowing power (the locked phase of the locked inverter) are also determined. Based on this, the target allocation power of each phase of each energy storage inverter can be obtained. This process requires calculating the power distribution of all phases to ensure that the missing power is fully supplemented, and also calculates the total power distribution of all energy storage inverters to ensure that the discharge limit and the maximum allowable charge and discharge power of the energy storage battery are met. It is understandable that this process confirms whether the power distribution is reasonable, that is, to ensure that the total power distribution meets the power dispatching requirements; if the distribution is unreasonable, the dispatching power of the non-locked phase is adjusted to meet the power limit.

[0092] This embodiment ensures the balance of power supply and demand and avoids power waste or shortage by reasonably scheduling the power of non-locked energy storage inverters and locked energy storage inverters. On the one hand, the discharge margin of non-locked energy storage inverters is fully utilized, so that the system can more effectively utilize the stored energy and improve the overall power distribution efficiency of the system. On the other hand, the power distribution between inverters is balanced through power scheduling to ensure that the system will not be unstable due to power overload or insufficient power, thereby improving the reliability of the energy storage system. In addition, after power scheduling, it is ensured that the discharge power and charging power of all energy storage inverters are within a reasonable range to avoid damage to batteries or equipment.

[0093] S108: Distribute power according to the target of each phase of each energy storage inverter and output power to match the load.

[0094] After the target allocated power of each phase of each energy storage inverter is obtained according to the above steps, each energy storage inverter needs to perform actual power output according to the target allocated power.

[0095] First, the power output of the non-locked energy storage inverter. Take energy storage inverter A as an example: A's L2 phase needs to discharge 1 kW according to the calculation result of S107; ensure that A's L2 phase power output reaches the set value and remains stable; monitor A's battery discharge status to ensure that it does not exceed its battery discharge limit; if the power output is unstable, adjust it, for example: if the L2 phase power output fluctuates too much, the PWM (pulse width modulation) control strategy can be adjusted; if the battery voltage drops abnormally, it may be necessary to limit the discharge power.

[0096] Secondly, lock the power regulation of the energy storage inverter. Take energy storage inverter B as an example: B's L2 phase needs to absorb 1 kW (i.e. charging) to balance the system; monitor B's battery charging status to ensure that it does not exceed its charging power limit; ensure that B's L3 phase gets the required 1 kW to meet the load demand; if B's ​​battery charging is limited, the power distribution of other phases needs to be adjusted to keep the overall system stable.

[0097] Thirdly, load power matching. It is understandable that the load side needs to receive the power output of the inverter in real time to ensure the power balance on the grid side; through the voltage and current sampling feedback system, the power output of each phase is adjusted in real time to prevent power shortage or overload; if the load demand changes (for example, the power demand of the L3 phase increases), the system should quickly adjust the power output and dynamically adapt to the load.

[0098] Finally, during the power output process, the system needs to conduct continuous monitoring to ensure the accuracy of power matching and make adjustments based on feedback information. Specific monitoring contents include: Real-time monitoring of voltage and current: Through current sensors, Hall sensors and other devices, the output power data of each phase of the energy storage inverter is collected in real time; if power deviation is found (for example, the target is 1kW, but the actual output is only 0.8 kW), the output power of the inverter needs to be adjusted. Battery status monitoring: Monitor the battery SOC (State of Charge) of the energy storage inverter; prevent overcharging and over-discharging, and adjust the power output limit when necessary. System safety control: Set abnormal status detection, such as overtemperature, overload, short circuit, etc., and take protective measures when abnormalities occur; optimize power distribution through intelligent scheduling algorithms to make power output more stable.

[0099] This embodiment ensures the stability, safety and efficiency of power dispatch through intelligent control strategy and real-time monitoring feedback, and ultimately enables the system to achieve accurate power allocation, improve energy utilization, and ensure reliable operation of the system.

[0100] The power dispatching process of the power allocation method of the three-phase parallel system proposed in the above embodiment is explained below in conjunction with Tables 1 to 10: Table 1 - Initial distribution power

[0101] Table 2 - Secondary distribution power

[0102] For Example 1, please refer to Tables 1 and 2, taking a locked energy storage inverter and a locked phase as an example. As shown in Table 1, it is known that the initial power distribution of each phase of the single-machine system A (energy storage inverter) is 2, 0, 2. The initial power distribution of each phase of the single-machine system B (energy storage inverter) is 2, 0, 0. The load power of L1, L2 and L3 is 4, 0, 3. The total battery discharge limit of the single-machine system A and B is 6 and 2. Assume that the maximum allowable charge and discharge power of each phase is 2. It should be noted that the total battery discharge limit here and in the subsequent ones are the discharge limits of the energy storage batteries described above, which will not be repeated.

[0103] First, by comparing the total output power and load power of each phase, it can be determined that the locked phase is L3 phase, and L1 and L2 phases are non-locked phases. Secondly, by comparing the three-phase total output power of each energy storage inverter and the corresponding discharge limit of the energy storage battery, it can be determined that the single-machine system B is a locked energy storage inverter and the single-machine system A is a non-locked energy storage inverter. Then, the difference between the load power corresponding to the lock and the sum of the initial distribution power of the non-locked energy storage inverter in the locked phase is calculated as the sum of the missing power. According to Table 1, the sum of the missing power is: 3-2=1, that is, the missing power required for the L3 phase of the single-machine system B is 1.

[0104] Secondly, it is determined whether the initial distribution power of phases L1 and L2 in the single-machine system B is zero, so as to determine the chargeable phase and the charge margin. According to Table 1, phase L2 of the single-machine system B is a chargeable phase, and its charge margin is 2.

[0105] Next, the discharge margin is obtained according to the initial distribution power of the L1 and L2 phases of the single-machine system A. According to Table 1, the discharge margin of the L2 phase of the single-machine system A is 2.

[0106] Finally, according to the missing power, charging margin and discharging margin, the target allocated power of each phase of each energy storage inverter is obtained. After the power allocation process described in the above embodiment, the data in Table 2 can be obtained: the corresponding allocated power of L3 of the single-machine system B is 1 (missing power), the corresponding allocated power of L2 of the single-machine system A is 1 (first scheduling power), and the corresponding allocated power of L2 of the single-machine system B is -1 (second scheduling power). After verification, the sum of the secondary allocated powers of each phase of the single-machine systems A and B meets the requirement of not exceeding their respective total battery discharge limits, the secondary allocated power of each phase meets the requirement of not exceeding the maximum allowable charge and discharge power of each phase, and the overall power of each phase is equal to its corresponding load power. That is, after the secondary power distribution, the surplus electricity in the energy storage battery of the inverter just supplements the power gap, and there is no need to borrow electricity from the power grid.

[0107] Table 3 - Initial power distribution

[0108] Table 4 - Secondary distribution power

[0109] For Example 2, please refer to Table 3 and Table 4, taking a locked energy storage inverter and a locked phase as an example. As shown in Table 3, it is known that the initial power distribution of each phase of the single-machine system A is 2, 1, 2. The initial power distribution of each phase of the single-machine system B is 2, 0, 0. The load power of L1, L2 and L3 is 4, 1, 3. The total battery discharge limit of the single-machine system A and B is 6 and 2. Assume that the maximum allowable charge and discharge power of each phase is 2.

[0110] First, by comparing the total output power and load power of each phase, it can be determined that the locked phase is L3 phase, and L1 and L2 phases are non-locked phases. Secondly, by comparing the three-phase total output power of each energy storage inverter and the corresponding discharge limit of the energy storage battery, it can be determined that the single-machine system B is a locked energy storage inverter and the single-machine system A is a non-locked energy storage inverter. Then, the difference between the load power corresponding to the lock and the sum of the initial distribution power of the non-locked energy storage inverter in the locked phase is calculated as the sum of the missing power. According to Table 3, the sum of the missing power is: 3-2=1, that is, the missing power required for the L3 phase of the single-machine system B is 1.

[0111] Secondly, it is determined whether the initial distribution power of phases L1 and L2 in the single-machine system B is zero, so as to determine the chargeable phase and the charge margin. According to Table 3, phase L2 of the single-machine system B is a chargeable phase, and its charge margin is 2.

[0112] Next, the discharge margin is obtained according to the initial distribution power of the L1 and L2 phases of the single-machine system A. According to Table 3, the discharge margin of the L2 phase of the single-machine system A is 1.

[0113] Finally, according to the missing power, charging margin and discharging margin, the target allocated power of each phase of each energy storage inverter is obtained. After the power allocation process described in the above embodiment, the data in Table 4 can be obtained: the corresponding allocated power of L3 of the single-machine system B is 1 (missing power), the corresponding redistributed power of L2 of the single-machine system A is 1 (first dispatching power), and the corresponding redistributed power of L2 of the single-machine system B is -1 (second dispatching power). That is, the target power of each phase of the single-machine system B is 2, -1, and 1 respectively; the target power of each phase of the single-machine system A is 2, 2, and 2. After verification, the sum of the secondary allocated power of each phase of the single-machine systems A and B meets the requirement of not exceeding their respective total battery discharge limits, the secondary allocated power of each phase meets the requirement of not exceeding the maximum allowable charge and discharge power of each phase, and the overall power of each phase is equal to its corresponding load power. That is, after the secondary power distribution, the surplus electricity in the energy storage battery of the inverter just supplements the power gap, and there is no need to borrow power from the power grid.

[0114] Table 5 - Initial power distribution

[0115] Table 6 - Secondary distribution power

[0116] For Example 3, please refer to Table 5 and Table 6, taking a locked energy storage inverter and a locked phase as an example. As shown in Table 5, it is known that the initial power distribution of each phase of the single-machine system A is 2, 1, 2. The initial power distribution of each phase of the single-machine system B is 2, 0, 0. The load power of L1, L2 and L3 is 4, 1, 4. The total battery discharge limit of the single-machine system A and B is 6 and 2. Assume that the maximum allowable charge and discharge power of each phase is 2.

[0117] First, by comparing the total output power and load power of each phase, it can be determined that the locked phase is L3 phase, and L1 and L2 phases are non-locked phases. Secondly, by comparing the three-phase total output power of each energy storage inverter and the corresponding discharge limit of the energy storage battery, it can be determined that the single-machine system B is a locked energy storage inverter and the single-machine system A is a non-locked energy storage inverter. Then, the difference between the load power corresponding to the lock and the sum of the initial distribution power of the non-locked energy storage inverter in the locked phase is calculated as the sum of the missing power. According to Table 5, the sum of the missing power is: 4-2=2, that is, the missing power required for the L3 phase of the single-machine system B is 2.

[0118] Secondly, it is determined whether the initial distribution power of phases L1 and L2 in the single-machine system B is zero, so as to determine the chargeable phase and the charge margin. According to Table 5, it can be seen that phase L2 of the single-machine system B is a chargeable phase, and its charge margin is 2.

[0119] Next, the discharge margin is obtained according to the initial distribution power of the L1 and L2 phases of the single-machine system A. According to Table 5, the discharge margin of the L2 phase of the single-machine system A is 1.

[0120] Finally, according to the missing power, charging margin and discharging margin, the target allocated power of each phase of each energy storage inverter is obtained. After the power allocation process described in the above embodiment, the data in Table 6 can be obtained: the corresponding allocated power of L3 of the single-machine system B is 1 (missing power), the corresponding redistributed power of L2 of the single-machine system A is 1 (first dispatching power), and the corresponding redistributed power of L2 of the single-machine system B is -1 (second dispatching power). That is, the target power of each phase of the single-machine system B is 2, -1, and 1 respectively; the target power of each phase of the single-machine system A is 2, 2, and 2. After verification, the sum of the secondary allocated power of each phase of the single-machine systems A and B meets the requirement of not exceeding their respective total battery discharge limits, and the secondary allocated power of each phase meets the requirement of not exceeding the maximum allowable charge and discharge power of each phase. However, at this time, the overall power of the L3 phase is not equal to its corresponding load power. That is, after the secondary power distribution, the surplus power in the energy storage battery of the inverter is not enough to fully supplement the power gap. At this time, the L3 phase still needs to be supplied by the power grid again, but it can also achieve the effect of reducing power supply from the power grid and saving costs.

[0121] Table 7 - Initial power distribution

[0122] Table 8 - Secondary distribution power

[0123] For Example 4, please refer to Tables 7 and 8, taking multiple locked energy storage inverters and one locked phase as an example. As shown in Table 7, it is known that the initial power distribution of each phase of the single-machine system A is 2, 0, 2. The initial power distribution of each phase of the single-machine system B is 2, 0, 0. The initial power distribution of each phase of the single-machine system C is 2, 0, 2. The initial power distribution of each phase of the single-machine system D is 2, 0, 0. The load power of L1, L2 and L3 is 8, 0, 6. The total battery discharge limit of the single-machine systems A, B, C and D is 6, 2, 6, 2. Assume that the maximum allowable charge and discharge power of each phase is 2.

[0124] First, by comparing the total output power and load power of each phase, it can be determined that the locked phase is L3 phase, and L1 and L2 phases are non-locked phases. Secondly, by comparing the three-phase total output power of each energy storage inverter and the corresponding discharge limit of the energy storage battery, it can be determined that the single-machine systems B and D are locked energy storage inverters, and the single-machine systems A and C are non-locked energy storage inverters. Then, the difference between the load power corresponding to the lock and the sum of the initial distribution power of the non-locked energy storage inverter in the locked phase is calculated as the sum of the missing power. According to Table 7, the sum of the missing power is: 6-2-2=2, that is, the sum of the missing power required for the L3 phase of the single-machine system B and D is 2. At this time, the equal division method can be used to determine that the missing power required for the L3 phase of the single-machine system B and D is 1 respectively.

[0125] Secondly, determine whether the initial distribution power of L1 and L2 phases in the single-machine systems B and D is zero, so as to determine the chargeable phase and the charge margin. According to Table 7, it can be seen that the L2 phase of the single-machine systems B and D is a chargeable phase, and its charge margin is 2.

[0126] Next, the discharge margin is obtained according to the initial distribution power of the L1 and L2 phases of the single-machine systems A and C. According to Table 7, the discharge margin of the L2 phase of the single-machine systems A and C is 1.

[0127] Finally, according to the missing power, charging margin and discharging margin, the target allocated power of each phase of each energy storage inverter is obtained. After the power allocation process described in the above embodiment, the data in Table 8 can be obtained: the corresponding allocated power of L3 of the single-machine system B and D is 1 (missing power), the corresponding redistributed power of L2 of the single-machine system A and C is 1 (first scheduling power), and the corresponding redistributed power of L2 of the single-machine system B and D is -1 (second scheduling power). That is, the target power of each phase of the single-machine system B and D is 2, -1, and 1 respectively; the target power of each phase of the single-machine system A and C is 2, 1, and 2. After verification, the sum of the secondary allocated power of each phase of the single-machine system A to D meets the requirement of not exceeding the total discharge limit of their respective batteries, the secondary allocated power of each phase meets the requirement of not exceeding the maximum allowable charge and discharge power of each phase, and the overall power of each phase is equal to the corresponding load power. That is, after the secondary power distribution, the surplus electricity in the energy storage battery of the inverter not only supplements the power gap, but also has a margin.

[0128] Table 9 - Initial power distribution

[0129] Table 10 - Secondary distribution power

[0130] For Example 5, please refer to Tables 9 and 10, taking multiple locked energy storage inverters and one locked phase as an example. As shown in Table 9, it is known that the initial power distribution of each phase of the single-machine system A is 2, 0, 2. The initial power distribution of each phase of the single-machine system B is 2, 0, 0. The initial power distribution of each phase of the single-machine system C is 2, 0, 2. The initial power distribution of each phase of the single-machine system D is 2, 0, 0. The load power of L1, L2 and L3 is 8, 0, 6. The total battery discharge limit of the single-machine systems A, B, C and D is 6, 2, 4, 2. Assume that the maximum allowable charge and discharge power of each phase is 2.

[0131] First, by comparing the total output power and load power of each phase, it can be determined that the locked phase is L3 phase, and L1 and L2 phases are non-locked phases. Secondly, by comparing the three-phase total output power of each energy storage inverter and the discharge limit of the corresponding energy storage battery, it can be determined that the single-machine systems B, C and D are locked energy storage inverters, and the single-machine system A is a non-locked energy storage inverter. It should be noted that although the three-phase total output power of the single-machine system C is equal to the discharge limit of the corresponding energy storage battery, the single-machine system C is set as a locked energy storage inverter, but according to the unused margin of each locked energy storage inverter in the locked phase described above, the unused margin of the L3 phase of the single-machine system C is 0. Therefore, it is only necessary to consider power allocation to the single-machine systems B and D. Then, the difference between the load power corresponding to the lock and the sum of the initial allocation power of the non-locked energy storage inverter in the locked phase is calculated as the sum of the missing power. According to Table 9, the sum of the missing powers is: 6-2-2=2, that is, the sum of the missing powers required by the L3 phases of the single-machine systems B and D is 2. Secondly, determine whether the initial distribution power of L1 and L2 phases in the single-machine systems B and D is zero, so as to determine the chargeable phase and the charge margin. According to Table 9, the L2 phase of the single-machine systems B and D is a chargeable phase, and its charge margin is 2.

[0132] Again, the discharge margin is obtained according to the initial distribution power of the L1 and L2 phases of the single-machine system A. According to Table 9, the discharge margin of the L2 phase of the single-machine system A is 2. It can be understood that even if the discharge margin of the L2 phase of the single-machine system A is 2, and the output is 2kW, it can just meet the total battery discharge limit of the single-machine system A without exceeding it.

[0133] Finally, according to the missing power, charging margin and discharging margin, the target allocated power of each phase of each energy storage inverter is obtained. After the power allocation process described in the above embodiment, the data in Table 10 can be obtained: the corresponding allocated power of L3 of the single-machine system B is 2 (missing power), the corresponding redistributed power of L2 of the single-machine system A is 2 (first scheduling power), and the corresponding redistributed power of L2 of the single-machine system B is -2 (second scheduling power). That is, the target power of each phase of the single-machine system B is 2, -2, 2 respectively; the target power of each phase of the single-machine system A is 2, 2, 2; the target power of each phase of the single-machine system C is 2, 0, 2; the target power of each phase of the single-machine system D is 2, 0, 0. After verification, the sum of the secondary allocated power of each phase of the single-machine system A to D meets the requirement of not exceeding the total discharge limit of their respective batteries, the secondary allocated power of each phase meets the requirement of not exceeding the maximum allowable charge and discharge power of each phase, and the overall power of each phase is equal to its corresponding load power. That is, after the secondary power distribution, the surplus electricity in the energy storage battery of the inverter just supplements the power gap.

[0134] The embodiment of the present application provides a power allocation method for a three-phase parallel system, which establishes an accurate power scheduling basis by obtaining the current power demand information, including the load power, charge and discharge margin, and missing power of each phase. Subsequently, according to the state of the energy storage inverter, the target power of each phase is intelligently allocated to ensure that the load demand is met and the energy storage device does not exceed the discharge or charging limit. Finally, the power output is executed, and combined with real-time monitoring and feedback adjustment, the system can quickly respond to load changes and maintain grid stability. Based on this, the problems of rigid inter-phase power and single-point bottleneck restricting overall performance of the traditional parallel system are solved, and the load adaptability and operation reliability of the parallel system are significantly improved. In addition, the safety of the energy storage inverter is also guaranteed, overload discharge or overcharging is avoided, and the life of the equipment is increased. Finally, through the intelligent power management mechanism, the distributed energy system can participate in grid scheduling more efficiently, with good economy, safety and scalability, and is suitable for a variety of energy storage and load scenarios.

[0135] Based on the power distribution method provided in the above embodiment, the present application embodiment further provides a power distribution device. Figure 4 , Figure 4 FIG. 1 is a schematic block diagram of the structure of the power distribution device. Figure 4 As shown, the power distribution device 200 includes: an acquisition module 210, a first confirmation module 220, a second confirmation module 230, a missing power calculation module 240, a charging margin calculation module 250, a discharging margin calculation module 260, a power scheduling calculation module 270 and a power distribution module 280. Among them, the acquisition module 210 is used to obtain the initial allocation power of each phase of each energy storage inverter; the first confirmation module 220 is used to determine the locked phase according to the initial allocation power of each phase of each energy storage inverter; the second confirmation module 230 is used to determine the locked energy storage inverter and the non-locked energy storage inverter according to the initial allocation power of each phase of each energy storage inverter and the discharge limit of the energy storage battery corresponding to each energy storage inverter; the missing power calculation module 240 is used to determine the missing of the locked phase of the locked energy storage inverter according to the locked energy storage inverter and the locked phase. Power; the charging remainder calculation module 250 is used to obtain the charging remainder according to the initial allocation power of the non-locked phase of the locked energy storage inverter; the discharging remainder calculation module 260 is used to obtain the discharging remainder according to the initial allocation power of the non-locked phase of the non-locked energy storage inverter; the power scheduling calculation module 270 is used to obtain the target allocation power of each phase of each energy storage inverter according to the missing power, the charging remainder and the discharging remainder; the power allocation module 280 is used to output power to match the load according to the target allocation power of each phase of each energy storage inverter.

[0136] It should be noted that the above power distribution device can execute the power distribution method provided in the embodiment of the present application, and has the corresponding functional modules and beneficial effects of the execution method. For technical details not fully described in the power distribution device embodiment, please refer to the power distribution method provided in the embodiment of the present application.

[0137] The present application also provides a three-phase parallel system. Figure 5 , which shows the hardware structure of the three-phase parallel system capable of executing the method described in the above embodiment. The three-phase parallel system 300 includes: at least one processor 310; and a memory 320 in communication with the at least one processor 310, Figure 5 A processor 310 is taken as an example. The memory 320 stores instructions that can be executed by the at least one processor 310, and the instructions are executed by the at least one processor 310 so that the at least one processor 310 can perform the power allocation method described in the above embodiment. The processor 310 and the memory 320 can be connected via a bus or other means. Figure 5 The example of connecting through bus is taken in the following.

[0138] The memory 320 is a non-volatile computer-readable storage medium that can be used to store non-volatile software programs, non-volatile computer executable programs and modules, such as program instructions / modules corresponding to the power allocation method in the embodiment of the present application. The processor 310 executes various functional applications and data processing of the server by running the non-volatile software programs, instructions and modules stored in the memory 320, that is, implementing the power allocation method described in the above embodiment.

[0139] The memory 320 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and applications required for at least one function; the data storage area may store data created according to the use of the computing device, etc. In addition, the memory 320 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some embodiments, the memory 320 may optionally include a memory remotely arranged relative to the processor 310, and these remote memories may be connected to the computing device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0140] The one or more modules are stored in the memory 320, and when executed by the one or more processors 310, the power allocation method described in the above embodiment is executed.

[0141] The above product can execute the method provided in the embodiment of the present application, and has the functional modules and beneficial effects corresponding to the execution method. For technical details not described in detail in this embodiment, please refer to the power allocation method described in any embodiment of the present application.

[0142] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, i.e., they may be located in one place, or may be distributed over multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0143] Through the description of the above embodiments, it can be clearly understood by those skilled in the art that each embodiment can be implemented by means of software plus a general hardware platform, or by hardware. It can be understood by those skilled in the art that all or part of the processes in the above embodiment methods can be implemented by instructing the relevant hardware through a computer program. The program can be stored in a computer-readable storage medium, and when the program is executed, it can include the processes of the embodiments of the above methods. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present application as above, which are not provided in detail for the sake of simplicity. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A power distribution method for a three-phase parallel system, wherein the three-phase parallel system comprises at least two energy storage inverters, characterized in that: The method comprises: Obtaining the initial distribution power of each phase of each of the energy storage inverters; Determining a locked phase and a non-locked phase according to the initially distributed power of each phase of each of the energy storage inverters; Determining a locked energy storage inverter and a non-locked energy storage inverter according to the initial allocated power of each phase of each energy storage inverter and the discharge limit of the energy storage battery corresponding to each energy storage inverter; Determining the missing power of the locked phase of the locked energy storage inverter according to the locked energy storage inverter and the locked phase; Obtaining a charge margin according to the initial distribution power of the non-locked phase of the locked energy storage inverter; Obtaining a discharge margin according to the initial distribution power of the non-locked phase of the non-locked energy storage inverter; Obtaining a target allocated power for each phase of each of the energy storage inverters according to the missing power, the charging margin, and the discharging margin; According to the target allocated power of each phase of each energy storage inverter, power output is performed to match the load.

2. The power distribution method according to claim 1, characterized in that: Determining a locked phase and an unlocked phase according to the initial distribution power of each phase of each energy storage inverter includes: Obtain the corresponding load power; Calculating the total output power of each phase according to the initial distribution power of each phase of each energy storage inverter; Comparing the total output power of each phase with the corresponding load power; The phase whose total output power is less than the corresponding load power is defined as the locked phase; otherwise, it is the non-locked phase.

3. The power distribution method according to claim 2, characterized in that: The step of determining a locked energy storage inverter and a non-locked energy storage inverter according to the initial allocated power of each phase of each energy storage inverter and the discharge limit of the energy storage battery corresponding to each energy storage inverter comprises: Calculating the three-phase total output power of each energy storage inverter according to the initial distribution power of each phase of each energy storage inverter; The energy storage inverter whose three-phase total output power is equal to the discharge limit of the energy storage battery is defined as a locked energy storage inverter; the energy storage inverter whose three-phase total output power is less than the discharge limit of the energy storage battery is defined as a non-locked energy storage inverter.

4. The power distribution method according to claim 3, characterized in that: Determining the missing power of the locked phase of the locked energy storage inverter according to the locked energy storage inverter and the locked phase includes: Obtaining the sum of the initial allocated powers of the non-locked energy storage inverters in the locked phase; The difference between the load power corresponding to the locking and the sum of the initial distribution powers of the non-locked energy storage inverters in the locking phase is the sum of the missing powers; The missing power of the locked phase of each locked energy storage inverter is determined according to the sum of the missing power, the number of the locked energy storage inverters and the maximum allowable discharge power.

5. The power distribution method according to claim 1, characterized in that: The method of obtaining the charging margin according to the initial distribution power of the non-locked phase of the locked energy storage inverter includes: Determining whether the initial distribution power of the non-locked phase in the locked energy storage inverter is zero; If the initial allocated power of the non-locked phase is not zero, it indicates that the non-locked phase is used to supply power to the load, and it is determined that the non-locked phase cannot perform a charging operation; If the initial allocated power of the non-locked phase is zero, it indicates that the non-locked phase is not used to power the load, and the non-locked phase is determined to be a chargeable phase; The maximum allowable charging power of the chargeable phase in the locked energy storage inverter is obtained as the charging margin.

6. The power distribution method according to claim 1, characterized in that: The method of obtaining the discharge margin according to the initial distribution power of the non-locked phase of the non-locked energy storage inverter comprises: Obtaining a discharge limit value of the energy storage battery corresponding to the non-locked energy storage inverter and a maximum allowable discharge power of the non-locked phase of the non-locked energy storage inverter; The discharge margin is calculated according to the discharge limit value of the energy storage battery corresponding to the non-locked energy storage inverter, the maximum allowable discharge power of the non-locked phase of the non-locked energy storage inverter, and the initial distribution power.

7. The power distribution method according to claim 1, characterized in that: The step of obtaining the target allocated power of each phase of each energy storage inverter according to the missing power, the charging margin and the discharging margin includes: Determine the non-locked phase for power scheduling in the non-locked energy storage inverter according to the discharge margin and the missing power, and obtain the first scheduling power of the non-locked phase for power scheduling in the non-locked energy storage inverter; Determine the non-locked phase for the power scheduling in the locked energy storage inverter according to the charge margin and the missing power, and obtain the second scheduling power of the non-locked phase for the power scheduling in the locked energy storage inverter; According to the missing power, the first dispatching power and the second dispatching power, the target allocated power of each phase of each energy storage inverter is obtained.

8. The power distribution method according to claim 7, characterized in that: The step of determining the non-locked phase for the power scheduling in the locked energy storage inverter according to the charge margin and the missing power, and obtaining the second scheduling power of the non-locked phase for the power scheduling in the locked energy storage inverter, comprises: Acquire the load power corresponding to the non-locked state used for the power scheduling in the locked energy storage inverter and the discharge limit value of the energy storage battery corresponding to the non-locked energy storage inverter; The second scheduling power is obtained according to the first scheduling power, the load power and the discharge limit of the energy storage battery.

9. A power distribution device for a three-phase parallel system, the three-phase parallel system comprising at least two energy storage inverters, characterized in that: The device comprises: An acquisition module, the acquisition module is used to acquire the initial distribution power of each phase of each energy storage inverter; A first confirmation module, the first confirmation module is used to determine a locked phase and a non-locked phase according to the initial distribution power of each phase of each energy storage inverter; A second confirmation module, the second confirmation module is used to determine a locked energy storage inverter and a non-locked energy storage inverter according to the initial distribution power of each phase of each energy storage inverter and the discharge limit value of the energy storage battery corresponding to each energy storage inverter; A missing power calculation module, the missing power calculation module is used to determine the missing power of the locked phase of the locked energy storage inverter according to the locked energy storage inverter and the locked phase; A charging remainder calculation module, the charging remainder calculation module is used to obtain the charging remainder according to the initial distribution power of the non-locked phase of the locked energy storage inverter; A discharge margin calculation module, the discharge margin calculation module is used to obtain the discharge margin according to the initial distribution power of the non-locked phase of the non-locked energy storage inverter; A power scheduling calculation module, the power scheduling calculation module is used to obtain the target allocation power of each phase of each energy storage inverter according to the missing power, the charging margin and the discharging margin; A power distribution module is used to distribute power according to the target of each phase of each energy storage inverter, and output power to match the load.

10. A three-phase parallel system, characterized in that: include: at least one processor; as well as, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 8.

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