Anti-flow control method, device and equipment for photovoltaic system based on single-phase inverter

Abstract

This application provides a method, apparatus, and device for anti-reverse current control of a photovoltaic system based on single-phase inverters. The method acquires and determines the maximum allowable output power and power absorption margin of each single-phase inverter based on its local load power and inverter output power. It then broadcasts the local load power, inverter output power, power absorption margin, and maximum allowable output power of each single-phase inverter to other single-phase inverters via a communication bus. When the local load power of any single-phase inverter changes, a power adjustment amount is dynamically allocated based on the power absorption margins broadcast by the other unchanged single-phase inverters. This power adjustment amount is used to independently adjust the actual inverter output power of each single-phase inverter. By setting up independent phase control for each single-phase inverter, the path of reverse current caused by excess single-phase power is cut off. The single-phase inverter performs local detection and decision-making, and combined with the communication bus, the system response speed is improved.

Description

Technical Field

[0001] This application relates to the fields of distributed photovoltaic power generation and smart grid technology, and in particular to a method, device and equipment for anti-reverse current control of photovoltaic systems based on single-phase inverters. Background Technology

[0002] The application of distributed photovoltaic (PV) systems in residential buildings such as villas and apartment complexes is increasing. These buildings typically use a three-phase four-wire power grid, but the distribution of their internal electrical loads is significantly unbalanced. For example, high-power devices such as air conditioners and charging stations are concentrated in one phase (e.g., phase A), while low-power loads such as lighting and kitchen appliances are distributed across other phases. This dynamic fluctuation of the load (e.g., changes in air conditioner start-stop and electric vehicle charging times) leads to significant and real-time differences in load power between phases. When a PV power generation system is connected to the grid using a traditional grid-connection scheme, if the PV output power of one phase is much greater than the local load consumption, while other phases are heavily loaded, the excess power from the lighter-loaded phase will be injected back into the grid, forming a "reverse current."

[0003] In related technologies, complex control algorithms based on a single three-phase inverter have high control logic redundancy, slow dynamic response speed, difficulty in coping with sudden load fluctuations, and poor stability under three-phase unbalanced conditions. Summary of the Invention

[0004] This application provides a method, device, and equipment for preventing reverse current in a photovoltaic system based on a single-phase inverter, which can reduce the occurrence of reverse current while improving response speed.

[0005] In a first aspect, embodiments of this application provide a method for preventing reverse current flow in a photovoltaic system based on single-phase inverters. This method controls at least two single-phase inverters connected to a photovoltaic module array, wherein each single-phase inverter is connected to a load. The method includes the following steps:

[0006] The maximum allowable output power of each single-phase inverter is determined based on its local load power and inverter output power. The maximum allowable output power is the maximum power value that the single-phase inverter is allowed to output to prevent reverse current. The local load power, inverter output power, and maximum allowable output power of each single-phase inverter are broadcast to other single-phase inverters via a communication bus and a peer-to-peer communication mode.

[0007] When the load power of any single-phase inverter changes, the power reduction of the single-phase inverter that has changed and the power absorption margin of the other single-phase inverters that have not changed are determined. The power absorption margin represents the increase in output power that the single-phase inverter can increase to prevent reverse flow in the current state. Based on the power reduction of the single-phase inverter that has changed and the power absorption margin of the other single-phase inverters that have not changed, a power adjustment amount is dynamically allocated. The power adjustment amount is used to independently adjust the actual inverter output power of each single-phase inverter. The adjusted actual inverter output power does not exceed the maximum allowable output power.

[0008] In one possible implementation, determining the maximum permissible output power of the single-phase inverter includes:

[0009] Calculate the difference between the local load power and the inverter output power of the single-phase inverter, and use it as the local power difference;

[0010] If the power difference of this phase is less than or equal to the first preset threshold, it is determined that there is a reverse current problem. Then, the difference between the load power of this phase and the power difference of this phase is taken as the maximum allowable output power.

[0011] If the difference in the power of the current phase is greater than the first preset threshold, then the preset power is taken as the maximum allowable output power.

[0012] In one possible implementation, the power absorption margin of each of the other unchanged single-phase inverters is determined as follows:

[0013] Based on the phase load power, inverter output power, and first preset threshold of each of the other unchanged single-phase inverters, the power absorption margin of each of the above single-phase inverters is determined.

[0014] In one possible implementation, determining the power reduction of the single-phase inverter when the local load power of any single-phase inverter changes includes:

[0015] After the load power of one of the single-phase inverters decreases, the power reduction of the single-phase inverter is determined based on the initial load power and maximum allowable output power of the single-phase inverter.

[0016] In one possible implementation, the dynamic allocation of power adjustment based on the changed power reduction of the single-phase inverter, the maximum allowable output power of the other unchanged single-phase inverters, and the power absorption margin includes:

[0017] The power reduction should be allocated preferentially to the single-phase inverter with the largest power absorption margin;

[0018] If the single-phase inverter with the largest power absorption margin cannot fully absorb the power reduction, the power reduction will be allocated according to a proportional weight, wherein the proportional weight is determined by the ratio between the power absorption margins of each single-phase inverter, and the inverter output power of each single-phase inverter after adjustment does not exceed the corresponding maximum allowable output power.

[0019] In one possible implementation, obtaining the local load power and inverter output power of each of the single-phase inverters includes:

[0020] Each single-phase inverter periodically collects the grid voltage of its phase, the inverter output current of its phase, and the load current of its phase;

[0021] The inverter output power is obtained based on the grid voltage of this phase and the inverter output current of this phase;

[0022] The load power of the current phase is obtained based on the grid voltage and the load current of the current phase.

[0023] Secondly, embodiments of this application provide a photovoltaic system anti-reverse current control device based on a single-phase inverter, comprising:

[0024] Photovoltaic module array;

[0025] At least two single-phase inverters, wherein the DC input terminal of the single-phase inverter is connected to the photovoltaic module array, and the AC output terminal of the single-phase inverter is connected to the power grid and the load respectively;

[0026] The single-phase inverter includes:

[0027] The power detection module is used to collect the local grid voltage, local inverter output current, and local load current of the single-phase inverter.

[0028] The control unit, connected to the power detection module, is used to determine the local load power and inverter output power of the single-phase inverter based on the data collected by the power detection module, and to determine the maximum allowable output power of the single-phase inverter accordingly. The maximum allowable output power is the maximum power value that the single-phase inverter is allowed to output to prevent reverse current.

[0029] The communication bus connects the control units of each single-phase inverter and is used to broadcast the local load power, inverter output power and maximum allowable output power of each single-phase inverter to other single-phase inverters in a peer-to-peer communication mode.

[0030] The control unit is further configured to, when the load power of any single-phase inverter changes, determine the power reduction of the single-phase inverter that has changed and the power absorption margin of each other single-phase inverter that has not changed, wherein the power absorption margin characterizes the output power value that the single-phase inverter can increase to prevent reverse flow in the current state; and dynamically allocate a power adjustment amount based on the power reduction of the single-phase inverter that has changed and the power absorption margin of each other single-phase inverter that has not changed, wherein the power adjustment amount is used to independently adjust the actual inverter output power of each single-phase inverter, and the adjusted actual inverter output power does not exceed the maximum allowable output power.

[0031] In one possible implementation, the photovoltaic system anti-reverse current control device based on a single-phase inverter further includes:

[0032] Three-phase four-wire circuit breaker;

[0033] The single-phase inverter is configured to have three units;

[0034] The AC output phase line terminal of each of the single-phase inverters is respectively connected to the line between the corresponding phase of the power grid and the corresponding phase load;

[0035] The AC output neutral terminals of each of the single-phase inverters are interconnected and connected together to the neutral terminal of the three-phase four-wire circuit breaker, so that the three single-phase inverters form a Y-type topology.

[0036] In one possible implementation, the power detection module includes:

[0037] The voltage sampling unit is used to collect the local grid voltage of the single-phase inverter;

[0038] The first current sampling unit is used to collect the local inverter output current of the single-phase inverter.

[0039] The second current sampling unit is used to collect the local load current of the single-phase inverter.

[0040] Thirdly, embodiments of this application provide an electronic device, including: a memory and a processor;

[0041] The memory stores computer-executed instructions;

[0042] The processor executes computer execution instructions stored in the memory, causing the processor to perform the first aspect and / or various possible implementations of the first aspect as described above.

[0043] Fourthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the first aspect and / or various possible implementations of the first aspect.

[0044] Fifthly, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the first aspect and / or various possible implementations of the first aspect.

[0045] The reverse current prevention control method, apparatus, and equipment for photovoltaic systems based on single-phase inverters provided in this application achieve independent phase control by setting at least two single-phase inverters, cutting off the path of reverse current caused by excess single-phase power, and improving control accuracy and reliability. The single-phase inverters perform local detection and decision-making, combined with a communication bus, to improve system response speed. Attached Figure Description

[0046] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0047] Figure 1 A flowchart illustrating the anti-reverse current control method for photovoltaic systems based on single-phase inverters provided in this application. Figure 1 ;

[0048] Figure 2 A flowchart illustrating the anti-reverse current control method for photovoltaic systems based on single-phase inverters provided in this application. Figure 2 ;

[0049] Figure 3 A flowchart illustrating a method for preventing reverse current flow in a photovoltaic system based on a single-phase inverter, provided in an embodiment of this application;

[0050] Figure 4 A block diagram illustrating the power coordination control principle among the three single-phase inverters provided in this application;

[0051] Figure 5 A schematic diagram of the anti-reverse current control device for a photovoltaic system based on a single-phase inverter provided in this application;

[0052] Figure 6 This is a waveform diagram showing the changes in the output power of each phase inverter in a traditional three-phase inverter scheme when the load on phase A suddenly decreases.

[0053] Figure 7 This is a waveform diagram showing the change in the output power of each phase inverter when the load on phase A suddenly decreases.

[0054] Figure 8A schematic diagram of the structure of the electronic device provided in this application.

[0055] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0056] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0057] In distributed photovoltaic (PV) systems, when the PV system is connected to the grid via a three-phase inverter, if the local load power consumption of a certain phase is much less than the PV output power of that phase, while other phases have heavier loads, the PV system cannot autonomously allocate energy between phases. This results in excess output power from the inverter with the light load, generating reverse current to the grid. This may lead to forced grid disconnection, or cause problems such as local voltage increases in the grid and deterioration of power quality.

[0058] In related technologies, photovoltaic systems mostly use three-phase inverters. These inverters suppress reverse current by sampling the three-phase load current and introducing negative-sequence and zero-sequence component compensation algorithms or control strategies based on instantaneous power theory. However, these control algorithms are complex, demand high processor performance, have limited dynamic response speed, and exhibit poor stability under drastic load fluctuations. Furthermore, three-phase inverters connect to multiple loads simultaneously; a failure in one inverter will cause the entire photovoltaic system to shut down, resulting in poor reliability.

[0059] In view of this, this application provides a reverse current control method for photovoltaic systems based on single-phase inverters. It employs independent single-phase inverters and implements phase-by-phase independent control and inter-phase coordination strategies to solve the reverse current phenomenon caused by three-phase load imbalance. Simultaneously, data transmission between single-phase inverters is achieved via a communication bus, improving the response speed of the inter-phase coordination strategy.

[0060] The execution subject of the embodiments of this application can be an electronic device with processing capabilities, such as a computer, server, laptop computer, etc., and this application does not limit it.

[0061] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0062] The reverse current control method for photovoltaic systems based on single-phase inverters proposed in this application is used to control at least two single-phase inverters connected to a photovoltaic module array, wherein the single-phase inverters are connected to a load.

[0063] Figure 1 A flowchart illustrating the anti-reverse current control method for photovoltaic systems based on single-phase inverters provided in this application. Figure 1 ,like Figure 1 As shown, the method includes:

[0064] S101. Obtain and determine the maximum allowable output power of each single-phase inverter based on the local load power and inverter output power of each single-phase inverter. The maximum allowable output power is the maximum power value that the single-phase inverter is allowed to output to prevent reverse current.

[0065] In the above, inverter output power refers to the actual usable power currently generated by the inverter. Local phase load power refers to the total power currently consumed by all electrical devices in this phase. Maximum allowable output power refers to the upper limit of power that the photovoltaic system allows the single-phase inverter to generate, to prevent power backflow. Power absorption margin refers to how much additional power a single-phase inverter can accept under its current state without causing reverse current. Power absorption margin is used to characterize the power absorption capacity of a single-phase inverter.

[0066] In some implementations, a detailed description is provided of how to obtain the local load power and inverter output power of each single-phase inverter. This method includes:

[0067] Each single-phase inverter periodically collects the grid voltage of its phase, the inverter output current of its phase, and the load current of its phase.

[0068] For example, the sampling period can be set to 10ms. It should be understood that this is just an example, and those skilled in the art can set the sampling period according to actual needs and hardware conditions.

[0069] The inverter output power is obtained based on the grid voltage and inverter output current of this phase.

[0070] The load power of this phase is obtained based on the grid voltage and load current of this phase.

[0071] In some implementations, a detailed description is provided of how to determine the maximum permissible output power of the single-phase inverter, including the following methods:

[0072] Calculate the difference between the local load power Pinvx and the inverter output power Ploadx of the single-phase inverter, and use it as the local power difference ΔPx=Ploadx-Pinvx.

[0073] If the phase power difference ΔPx is less than or equal to the first preset threshold ΔPset, it is determined that there is a reverse current problem. The difference between the phase load power and the phase power difference is then taken as the maximum allowable output power.

[0074] The aforementioned first preset threshold is set as a positive threshold value, for example, it can be set to 50W, to prevent malfunctions caused by noise disturbance.

[0075] For example, if ΔPx ≤ ΔPset, then a reverse current problem is considered to exist in this phase. In this case, the maximum allowable output power of the single-phase inverter needs to be immediately set to: Pmaxx = Ploadx - ΔPset.

[0076] When a reverse current problem is detected, it means that the inverter output power of the single-phase inverter must be reduced to ensure that a small amount of power is always supplied to the load by the grid, thereby avoiding reverse current.

[0077] If the power difference ΔPx of this phase is greater than the first preset threshold ΔPset, then the preset power will be used as the maximum allowable output power.

[0078] The preset power can be set based on the maximum power point tracking (MPPT) results or other system requirements, which is a conventional technique in this field.

[0079] One of the core improvements of this application is how to dynamically adjust the maximum allowable output power and perform coordinated control based on the real-time operating status when a reverse flow problem is detected. The specific implementation method will be described in detail below.

[0080] S102. Through the communication bus and using a peer-to-peer communication mode, broadcast the local load power, inverter output power and maximum allowable output power of each single-phase inverter to other single-phase inverters.

[0081] For example, the communication bus described above can be configured as a CAN bus or an industrial fieldbus such as RS-485. This communication bus connects the control units of at least two single-phase inverters, enabling low-latency, high-speed conversion and coordinated control of inter-phase power information. Generally, low latency here refers to a response time of less than 10ms.

[0082] This embodiment does not require an additional central controller and adopts a peer-to-peer communication mode.

[0083] S103. When the load power of any single-phase inverter changes, determine the power reduction of the single-phase inverter that has changed and the power absorption margin of the other single-phase inverter that has not changed. The power absorption margin represents the output power that the single-phase inverter can increase to prevent reverse flow in the current state.

[0084] In some implementations, a detailed description is provided of how to determine the power reduction of the single-phase inverter, specifically including: after the load power of one of the single-phase inverters decreases, determining the power reduction of the single-phase inverter based on the initial load power and maximum allowable output power of the single-phase inverter.

[0085] In some implementations, a detailed description is provided of how to determine the power absorption margin of each of the other unchanged single-phase inverters, specifically: the power absorption margin of the other single-phase inverters is determined based on the local load power, inverter output power, and a first preset threshold of each of the other unchanged single-phase inverters.

[0086] S104. Based on the power reduction of the single-phase inverter that has changed and the power absorption margin of the other single-phase inverters that have not changed, dynamically allocate the power adjustment amount. The power adjustment amount is used to independently adjust the actual inverter output power of each single-phase inverter. The adjusted actual inverter output power does not exceed the maximum allowable output power.

[0087] By periodically broadcasting and storing power information, each inverter can monitor the load status of other phases in real time. This power information includes the load power of its own phase, the inverter's output power, and the maximum allowable output power. For example, after phase A broadcasts its power information, phases B and C receive and store this information, calculating their own power absorption margins to provide data support for subsequent power transfer. This technology improves the real-time performance and accuracy of inter-phase coordination by dynamically updating power difference information, thereby more efficiently allocating power adjustments while preventing reverse current flow and reducing photovoltaic power generation losses.

[0088] In the above embodiment, the power absorption margin of each unchanged single-phase inverter is determined by receiving the local load power and inverter output power broadcast by other single-phase inverters.

[0089] It is understood that in some embodiments, each single-phase inverter calculates its own power absorption margin and directly broadcasts the power absorption margin. Then, the power adjustment amount is dynamically allocated based on the power absorption margin.

[0090] The reverse current prevention control method for photovoltaic systems based on single-phase inverters provided in this application independently determines whether a single-phase inverter has a reverse current problem by judging the relationship between the phase power difference of each single-phase inverter and a first preset threshold. It achieves reverse current prevention control in three-phase load imbalance scenarios by adjusting the maximum allowable output power under different conditions. This concept abandons the centralized control mode of traditional three-phase integrated inverters, instead adopting a modular architecture and utilizing local detection and peer-to-peer communication to achieve distributed intelligent decision-making, thus avoiding reverse current problems and maximizing the local absorption efficiency of photovoltaic power generation.

[0091] The reverse current prevention control method for photovoltaic systems based on single-phase inverters provided in this application realizes the transformation from local autonomy to global optimization in multi-single-phase inverter systems by introducing a collaborative decision-making mechanism based on real-time communication.

[0092] When the load of a certain phase suddenly decreases and there is a potential risk of reverse current, the system does not simply reduce the output of the inverter of that phase. Instead, it first treats the excess "power adjustment amount" of that phase as an adjustable resource and dynamically redistributes it according to the "power absorption margin" (i.e. the potential of other phases to receive additional photovoltaic power without generating reverse current) broadcast in real time by other phases.

[0093] This process is equivalent to creating a real-time power allocation market within the system, enabling intelligent transfer and consumption of electrical energy between different phases. The ultimate effect is to maximize the overall self-consumption rate of photovoltaic power generation within the local load group while strictly preventing backflow to the grid, thus reducing the need to purchase electricity from the grid. Simultaneously, through smooth power transfer, it reduces frequent inverter start-ups and shutdowns or sharp power drops caused by load fluctuations, enhancing system stability and power quality. Furthermore, this collaborative mechanism endows the system with superior load adaptability, enabling it to proactively adapt to random fluctuations in load across different phases, thereby improving the overall energy efficiency and economic benefits of the photovoltaic system.

[0094] Figure 2 A flowchart illustrating the anti-reverse current control method for photovoltaic systems based on single-phase inverters provided in this application. Figure 2 ,like Figure 2 As shown, in this embodiment... Figure 1 Based on the examples, this paper details how to dynamically allocate power adjustment amounts based on the power reduction of the changed single-phase inverter, the maximum allowable output power of the other unchanged single-phase inverters, and their power absorption margins. This method includes:

[0095] S201: Prioritize allocating the power reduction to the single-phase inverter with the largest power absorption margin;

[0096] S202: If the single-phase inverter with the largest power absorption margin cannot fully absorb the power reduction, the power reduction will be allocated according to a proportional weight. The proportional weight is determined by the ratio between the power absorption margins of each single-phase inverter, and the inverter output power of each single-phase inverter after adjustment shall not exceed the corresponding maximum allowable output power.

[0097] In this embodiment, the adjusted inverter output power of each single-phase inverter does not exceed the upper limit of Maximum Power Point Tracking (MPPT).

[0098] The purpose of maximum power point tracking (MPPT) is to adjust the operating voltage and current of the photovoltaic module array in real time so that it always operates at the maximum power output point (MPP) under the current environmental conditions such as light and temperature, and the maximum allowable output power required by this application.

[0099] This technology is typically implemented by the MPPT algorithm module in an inverter or dedicated controller. It continuously samples the electrical parameters on the DC side and dynamically fine-tunes the operating point of the power converter based on specific algorithms (such as the perturbation observation method or the incremental conductance method), thereby overcoming the nonlinearity of the output characteristics of photovoltaic panels, maximizing the extraction of usable electrical energy from the photovoltaic array, and improving the overall energy harvesting efficiency of the system.

[0100] The reverse current control method for photovoltaic systems based on single-phase inverters provided in this application optimizes the power transfer path by allocating the power reduction amount according to the power absorption margin ratio.

[0101] For example, when phase A needs to reduce its output by 4.85kW, phases B and C allocate the reduction according to their power absorption margins to avoid energy waste caused by equal distribution.

[0102] This technology improves the local absorption efficiency of photovoltaic power generation by prioritizing the phase with the largest absorption capacity, thus reducing power generation losses caused by power limitations.

[0103] Figure 3 This is a schematic flowchart illustrating a specific implementation method for a photovoltaic system anti-reverse current control method based on single-phase inverters provided in this application. The example uses a photovoltaic system comprising three single-phase inverters: inverter A, inverter B, and inverter C. Figure 3 As shown, the method includes:

[0104] S301: Real-time data acquisition. Each single-phase inverter periodically (e.g., every 10ms) synchronously acquires the local grid voltage Ux (x=A,B,C), the local inverter output current Iinvx, and the local load current Iloadx through its local power detection module.

[0105] The key parameters obtained from the calculation are: the inverter output power Pinvx for this phase and the load power Ploadx for this phase.

[0106] S302: Local backflow risk assessment and power limit calculation.

[0107] Each single-phase inverter independently determines whether there is a risk of reverse current in its own phase.

[0108] Define the phase power difference ΔPx = Ploadx - Pinvx.

[0109] If ΔPx > ΔPset, then this phase is considered safe with no risk of reverse current. This phase inverter can operate in maximum power point tracking (MPPT) mode or have its output set according to other requirements.

[0110] If ΔPx ≤ ΔPset, then the phase is considered to have a risk of reverse current. In this case, the inverter of this phase immediately sets its maximum allowable output power limit Pmaxx to: Pmaxx = Ploadx - ΔPset.

[0111] At this point, the inverter must reduce its output to ensure that a small amount of power is always supplied to the load from the grid, thereby absolutely avoiding reverse current.

[0112] S303: Phase-to-phase power coordination and redistribution.

[0113] The three single-phase inverters broadcast their respective Ploadx, Pinvx, Pmaxx (or actual output power commands) and available expansion capacity in real time via the CAN bus.

[0114] The aforementioned potential capacity includes power absorption margin. When the Ploadx of a certain phase is much greater than the current Pinvx, then that phase has capacity space.

[0115] It should be noted that Ploadx being much greater than the current Pinvx means that the difference between Ploadx and Pinvx is greater than the second preset threshold.

[0116] In this step, the coordination goal is to maximize the local consumption of photovoltaic power generation and reduce power waste while ensuring that no reverse flow occurs in any phase.

[0117] The coordination algorithm is that when a phase (let's say phase A) needs to reduce its output power due to a lighter load (in this case, the power reduction is ΔPreduce), the system does not directly discard this power. Instead, it adjusts the output power of the inverters in other phases based on the power absorption margin of other phases.

[0118] The coordination algorithm evaluates the load status of phases B and C in real time.

[0119] Calculate the current power absorption margin of phases B and C. The formula for power absorption margin is as follows: Marginy = Ploady - Pinvy - ΔPset (y = B, C).

[0120] Select the phase with the largest power absorption margin. For example, phase B has the largest power absorption margin.

[0121] If the power absorption margin of phase B is greater than the power reduction ΔPreduce, the system generates a coordination command: the phase A inverter will reduce its output power by the power absorption margin ΔPreduce, while the phase B inverter will attempt to increase its output power (the increase is approximately equal to ΔPreduce) without exceeding its MPPT limit and PloadB-ΔPset.

[0122] The purpose of this is to "transfer" the power that phase A cannot absorb to phase B, which has the capacity to absorb it, thereby avoiding reverse flow while keeping the total output power of the system basically unchanged.

[0123] If the power absorption margin of phase B is not greater than the power reduction ΔPreduce, then the power absorption margin of phase B is insufficient to fully absorb the power reduction ΔPreduce. In this case, the power is allocated to phases B and C according to the margin value. The remaining part will require the inverter of phase A to reduce its output, resulting in a temporary decrease in the total photovoltaic output.

[0124] This coordination process is dynamic and continuous, and can quickly respond to any changes in load.

[0125] S304: Power command execution and closed-loop control. Each inverter, based on its locally calculated maximum allowable output power Pmaxx or a coordinated power command, rapidly adjusts the switching state of its power devices (such as IGBTs) through its internal current loop or power loop controller to precisely control the output power and ensure that the actual output matches the command.

[0126] In some embodiments, a specific application scenario of the anti-reverse current control method for photovoltaic systems based on single-phase inverters in this application is proposed, which is a villa.

[0127] It should be noted that the following data are for illustrative purposes only and should be adjusted according to actual needs in practical applications. In this application scenario, the first preset threshold is 0.05kW.

[0128] Specifically, a detached villa has 15kWp photovoltaic modules installed on its roof. Three 5kW single-phase grid-connected inverters (brand and model optional, such as Huawei SUN2000-5KTL-L1) are installed separately for phases A, B, and C.

[0129] Initial state: Phase A load (mainly air conditioner) 3.5kW, Phase B load (kitchen appliances) 1.0kW, Phase C load (lighting and sockets) 0.5kW. Each phase inverter is operating at full capacity of 5kW per MPPT.

[0130] Operating conditions change: In the afternoon, the air conditioner in phase A was turned off, and the load suddenly dropped to 0.2kW.

[0131] System response: The A-phase inverter detected that PloadA (0.2kW) was much smaller than PinvA (5kW), ΔPA<<ΔPset, and immediately triggered reverse current protection.

[0132] Calculate PmaxA = 0.2kW - 0.05kW = 0.15kW. Therefore, phase A needs to reduce its output by approximately 4.85kW (5kW - 0.15kW = 4.85kW). Simultaneously, phase A broadcasts the power reduction ΔPreduce = 4.85kW via the CAN bus.

[0133] The load power of phase B and phase C inverters and the current inverter output power: PloadB=1.0kW, PinvB=5kW. At this time, PinvB>=PloadB-ΔPset, and the original state has reversed the current.

[0134] The initial state needs to be corrected: the initial inverter output power of each phase should be slightly lower than the load power of that phase. Assuming the initial inverter output power is: A: 3.0kW, B: 0.8kW, C: 0.4kW, the total is 4.2kW ​​< 15kW, which is a margin.

[0135] Assume that the MarginB of phase B = 1.0kW - 0.8kW - 0.05kW = 0.15kW.

[0136] The margin of phase C is 0.5kW - 0.4kW - 0.05kW = 0.05kW.

[0137] At this point, the total power absorption margin of phases B and C, 0.2kW, is much less than 4.85kW.

[0138] Therefore, the A-phase inverter first reduces its output to 0.15kW (to avoid reverse current), while the B-phase and C-phase inverters increase their output to their maximum allowable values ​​(0.95kW for B-phase and 0.45kW for C-phase). The total system output decreases from 4.2kW ​​to 0.15 + 0.95 + 0.45 = 1.55kW.

[0139] Since the MPPT power of the photovoltaic panel is much greater than this value, the excess power is absorbed by the photovoltaic panel itself (voltage rises, deviating from the MPPT point). When the load on phase B or phase C increases, the inverter output can increase accordingly.

[0140] In this embodiment, the initial power setting has been corrected to better reflect the actual control logic.

[0141] The embodiments of this application precisely target the specific application scenario of villas and the problem of severe imbalance in their three-phase loads. The technical solutions of the embodiments of this application are highly specialized and effective.

[0142] In some embodiments, a specific application scenario of the anti-reverse flow control method for photovoltaic systems based on single-phase inverters in this application is proposed, which is a rainy weather scenario.

[0143] In this embodiment, due to cloudy and rainy weather and insufficient sunlight, the maximum output power of the photovoltaic panel is lower than the load requirements of each phase.

[0144] The photovoltaic system automatically enters power optimization mode. Each phase inverter prioritizes supplying power to its own phase load; if the photovoltaic power of its own phase is insufficient, it is supplemented by the grid. Inter-phase coordination mainly focuses on whether there is a small margin of power generation in individual phases that can be utilized, but reverse current prevention is the absolute premise, and the system always operates stably.

[0145] Figure 4 The block diagram of the power coordination control principle between the three single-phase inverters provided in this application is as follows: Figure 4 As shown, this system consists of a three-phase power coordination and control unit composed of single-phase inverter A, single-phase inverter B, and single-phase inverter C. Each single-phase inverter communicates with other single-phase inverters via a CAN bus. Each single-phase inverter contains three functional units: a local data module, a coordination decision module, and a power control module.

[0146] Single-phase inverter A: Collects the load power PloadA and the inverter output power PinvA of this phase, and determines the power reduction amount ΔPreduce that needs to be reduced for this phase.

[0147] Single-phase inverter B: Collects the load power PloadB and the inverter output power PinvB of this phase, and calculates the power absorption margin MarginB of this phase (i.e., the upper limit of the additional power that this phase can safely absorb, representing the redundant power space).

[0148] Single-phase inverter C: Collects the local load power PloadC and the local inverter output power PinvC, and calculates the local power absorption margin MarginC.

[0149] Each single-phase inverter establishes a data interaction channel through the CAN bus, broadcasting its locally collected key parameters (including ΔPreduce, MarginB, and MarginC) to the bus to achieve real-time sharing of three-phase power information and provide data support for subsequent coordination and decision-making.

[0150] Single-phase inverter A directly performs a power reduction operation and issues an instruction to the power control module to reduce the output power of this phase according to the locally determined ΔPreduce.

[0151] Single-phase inverter B makes a decision according to the magnitude relationship between ΔPreduce and MarginB:

[0152] If ΔPreduce < MarginB: It is determined that the power absorption margin of phase B can fully承接 the reduced power of phase A, and an instruction to increase the power of this phase by ΔPreduce is issued to the power control module.

[0153] If ΔPreduce ≥ MarginB: It is determined that phase B cannot承接 all of ΔPreduce alone. ΔPreduce is allocated to phase B and phase C according to the ratio of MarginB:MarginC, and corresponding power increase instructions are issued to the power control module.

[0154] Single-phase inverter C makes a decision according to the magnitude relationship between ΔPreduce and MarginB:

[0155] If ΔPreduce < MarginB: It is determined that phase B can fully承接 the reduced power of phase A, and an instruction to keep the power of this phase unchanged is issued to the power control module;

[0156] If ΔPreduce ≥ MarginB: The remaining ΔPreduce to be absorbed is allocated to phase B and phase C according to the ratio of MarginB:MarginC, and corresponding power increase instructions are issued to the power control module.

[0157] The power control module of each single-phase inverter combines the locally calculated maximum allowable power Pmaxx (x is A / B / C, representing the safety output power upper limit of each phase inverter), and the power adjustment instructions issued by the coordination decision module (phase A reduces power, phases B / C increase power according to the decision result), and performs the final power output adjustment to ensure that the power output of each phase not only meets the coordination allocation requirements but also does not exceed its own safety upper limit, realizing the balanced and stable control of three-phase power.

[0158] When single-phase inverter A in the system needs to reduce the output power by ΔPreduce due to load or working condition requirements, this requirement is shared with the power absorption margins of phases B and C through the CAN bus; single-phase inverter A directly performs a power reduction operation, and single-phase inverters B and C承接 the reduced power of phase A according to their own power absorption margins and decision logic according to the rule of "phase B承接 first, and when insufficient, phases B / C are allocated proportionally".

[0159] Finally, each phase executes the coordinated instructions through the power control module to achieve the coordinated balance of three-phase power, avoid single-phase overload / underload, and improve the rationality of system power distribution and operation stability.

[0160] Figure 5 The schematic diagram of the anti-reverse current control device for a photovoltaic system based on a single-phase inverter provided in this application is as follows: Figure 5 As shown, the photovoltaic system anti-reverse current control device based on a single-phase inverter provided in this embodiment includes:

[0161] Photovoltaic module array 501; in villa applications, the total capacity of photovoltaic module array 501 is configured according to the villa's roof area and sunlight conditions, for example, 10kW~20kW. The array can be appropriately grouped and connected to each phase inverter respectively.

[0162] At least two single-phase inverters 502 are provided. The DC input terminal of the single-phase inverter is connected to the photovoltaic module array, and the AC output terminal of the single-phase inverter is connected to the power grid and the load respectively. Among them, the single-phase inverters 502 are preferably single-phase grid-connected inverters of the same model and specifications. Taking three single-phase inverters 502 as an example, the three single-phase inverters correspond to the A, B and C phases of the power grid respectively.

[0163] Each single-phase inverter 502 includes a power detection module 5021, which is used to collect the local grid voltage, local inverter output current and local load current of the single-phase inverter.

[0164] The aforementioned power detection module 5021 can be composed of a sensor and a current transformer, and is used to collect grid voltage and current data.

[0165] For example, the power detection module 5021 samples various parameters of the local inverter in real time.

[0166] The local load current is obtained by installing a current transformer (CT) between the grid connection point and the local load branch.

[0167] The single-phase inverter 502 includes a control unit 5022 connected to a power detection module, which is used to determine the local load power and inverter output power of the single-phase inverter based on the data collected by the power detection module, and to determine the maximum allowable output power of the single-phase inverter accordingly. The maximum allowable output power is the maximum power value that the single-phase inverter is allowed to output to prevent reverse current.

[0168] It should be noted that the inverter output power in this application refers to the active power output of the inverter. Of course, the reactive power output of the inverter can be calculated based on the collected data.

[0169] The control unit 5022 has a built-in anti-reverse flow control algorithm that calculates and adjusts the power output command of the local inverter in real time based on the detected power information.

[0170] The single-phase inverter 502 includes a DC / AC conversion circuit 503, which is used to convert AC power into DC power.

[0171] The communication bus 503 connects to the control unit of each single-phase inverter and is used to broadcast the local load power, inverter output power and maximum allowable output power of each single-phase inverter to other single-phase inverters in a peer-to-peer communication mode.

[0172] The communication bus 503 uses industrial fieldbuses such as CAN bus or RS-485 to connect the control units of three single-phase inverters, enabling low-latency, high-speed information exchange and coordinated control of power information between the three phases. By setting up the communication bus 503, no additional central controller is needed; a peer-to-peer communication mode is employed.

[0173] The control unit 5022 is further configured to, when the load power of any single-phase inverter changes, determine the power reduction of the single-phase inverter that has changed and the power absorption margin of the other single-phase inverters that have not changed, wherein the power absorption margin characterizes the output power that the single-phase inverter can increase to prevent reverse flow in the current state; and dynamically allocate a power adjustment amount based on the power reduction of the single-phase inverter that has changed and the power absorption margin of the other single-phase inverters that have not changed, wherein the power adjustment amount is used to independently adjust the actual inverter output power of each single-phase inverter, and the adjusted actual inverter output power does not exceed the maximum allowable output power.

[0174] In this embodiment, each single-phase inverter collaborates on an autonomous decision-making basis, and the control algorithm is based on instantaneous power difference judgment, which is simple, efficient, and has a fast response speed.

[0175] Figure 6 This is a waveform diagram showing the changes in the output power of each phase inverter in a traditional three-phase inverter scheme when the load on phase A suddenly decreases. Figure 7 This is a waveform diagram showing the change in the output power of each phase inverter when the load on phase A suddenly decreases.

[0176] like Figure 6 , Figure 7 As shown, the example of a sudden decrease in the load of phase A is used for illustration.

[0177] Figure 6 The waveform corresponds to the waveform change of the output power of each phase inverter in a traditional three-phase inverter scheme when the load on phase A suddenly decreases.

[0178] When the load on phase A suddenly decreases, the power of the load on phase A also suddenly decreases. At this time, the output power of the inverter in phase A does not respond in time, and reverse current occurs in phase A. After 200ms, the output power of the inverter in phase A begins to decrease in order to resolve the reverse current problem.

[0179] Figure 7The waveform corresponds to the waveform change of the output power of each phase inverter under the same operating conditions in the technical solution of this application.

[0180] When the load on phase A suddenly decreases, the power of the load on phase A decreases suddenly, and the output power of the inverter on phase A responds in a timely manner and decreases smoothly, so that no reverse current phenomenon occurs.

[0181] Meanwhile, while ensuring that no reverse current occurs in phase B, the output power of the inverter in phase B is increased to keep the total output power constant.

[0182] In one possible implementation, such as Figure 5 As shown, the anti-reverse current control device for photovoltaic systems based on single-phase inverters also includes a three-phase four-wire circuit breaker 504.

[0183] Three single-phase inverters are configured.

[0184] The AC output phase line terminals of each single-phase inverter are respectively connected to the corresponding phase line of the power grid and the corresponding phase load on the line.

[0185] The AC output neutral terminals of each single-phase inverter are interconnected and connected together to the neutral terminal of a three-phase four-wire circuit breaker, so that the three single-phase inverters form a Y-type topology.

[0186] This application embodiment uses three independently controlled single-phase inverters to form a Y-connected topology. This characteristic architecture is specifically designed to solve the three-phase unbalanced reverse current problem in scenarios such as villas. This topology itself has the advantages of modularity, low cost, and high reliability.

[0187] In this embodiment, the AC output terminals of the three single-phase inverters are connected to phases A, B, and C of the power grid, respectively, and their neutral points are connected together and connected to the neutral line (zero line) of the power grid, forming a standard Y-connection. The single-phase inverters are connected to the public power grid through a three-phase four-wire circuit breaker.

[0188] In one possible implementation, the power detection module 5021 includes:

[0189] The voltage sampling unit is used to collect the local grid voltage of the single-phase inverter;

[0190] The first current sampling unit is used to collect the local inverter output current of the single-phase inverter.

[0191] The second current sampling unit is used to collect the local load current of the single-phase inverter.

[0192] In one possible implementation, the control unit 5022 is specifically used for:

[0193] Calculate the difference between the load power of the single-phase inverter and the output power of the inverter, and use it as the power difference of the single-phase inverter.

[0194] If the power difference of this phase is less than or equal to the first preset threshold, then the difference between the load power of this phase and the power difference of this phase shall be taken as the maximum allowable output power.

[0195] If the power difference of this phase is greater than the first preset threshold, then the preset power will be used as the maximum allowable output power.

[0196] In one possible implementation, the control unit 5022 is specifically used for:

[0197] Based on the load power of the other single-phase inverters, the inverter output power, and the first preset threshold, the power absorption margin of the other single-phase inverters is calculated.

[0198] In one possible implementation, the control unit 5022 is specifically used for:

[0199] Prioritize allocating the power reduction to the single-phase inverter with the largest power absorption margin;

[0200] If the single-phase inverter with the largest power absorption margin cannot fully absorb the power reduction, the power reduction will be allocated according to a proportional weight. The proportional weight is determined by the ratio between the power absorption margins of each single-phase inverter, and the inverter output power of each single-phase inverter after adjustment shall not exceed the corresponding maximum allowable output power.

[0201] In one possible implementation, the control unit 5022 is specifically used for:

[0202] Each single-phase inverter periodically collects the grid voltage of its phase, the inverter output current of its phase, and the load current of its phase;

[0203] The grid voltage for this phase is obtained based on the grid voltage for this phase and the output current of the inverter for this phase.

[0204] The inverter output power is obtained based on the grid voltage and load current of this phase.

[0205] The photovoltaic system anti-reverse flow control device based on a single-phase inverter provided in this embodiment can execute the method provided in the above method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0206] Figure 8 A schematic diagram of the structure of the electronic device provided in this application. Figure 8As shown, the electronic device 700 provided in this embodiment includes at least one processor 701 and a memory 702. Optionally, the device 700 further includes a communication component 703. The processor 701, memory 702, and communication component 703 are connected via a bus 704.

[0207] In a specific implementation, at least one processor 701 executes computer execution instructions stored in memory 702, causing at least one processor 701 to perform the above-described method.

[0208] The specific implementation process of processor 701 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0209] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0210] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0211] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0212] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0213] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0214] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0215] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0216] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0217] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0218] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0219] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0220] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0221] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A method for preventing reverse current flow in a photovoltaic system based on a single-phase inverter, characterized in that, This method is used to control at least two single-phase inverters connected to a photovoltaic module array, wherein the single-phase inverters are connected to a load; The method includes the following steps: The maximum allowable output power of each single-phase inverter is determined based on the load power of the current phase and the output power of the inverter. The maximum allowable output power is the maximum power value that the single-phase inverter is allowed to output to prevent reverse current. Through the communication bus and using a peer-to-peer communication mode, the local load power, inverter output power and maximum allowable output power of each single-phase inverter are broadcast to other single-phase inverters. When the load power of any single-phase inverter changes, the power reduction of the single-phase inverter that has changed and the power absorption margin of the other single-phase inverter that has not changed are determined, wherein the power absorption margin characterizes the output power that the single-phase inverter can increase to prevent reverse flow in the current state. Based on the power reduction of the single-phase inverter that has changed and the power absorption margin of the other single-phase inverters that have not changed, a power adjustment amount is dynamically allocated. The power adjustment amount is used to independently adjust the actual inverter output power of each single-phase inverter, and the adjusted actual inverter output power does not exceed the maximum allowable output power.

2. The method according to claim 1, characterized in that, Determining the maximum allowable output power of the single-phase inverter includes: Calculate the difference between the local load power and the inverter output power of the single-phase inverter, and use it as the local power difference; If the power difference of this phase is less than or equal to the first preset threshold, it is determined that there is a reverse current problem. Then, the difference between the load power of this phase and the power difference of this phase is taken as the maximum allowable output power. If the difference in the power of the current phase is greater than the first preset threshold, then the preset power is taken as the maximum allowable output power.

3. The method according to claim 2, characterized in that, Determine the power absorption margin of each single-phase inverter that has not changed, specifically as follows: Based on the phase load power, inverter output power, and first preset threshold of each of the other unchanged single-phase inverters, the power absorption margin of each of the above single-phase inverters is determined.

4. The method according to claim 1, characterized in that, When the load power of any single-phase inverter changes, the determination of the power reduction of the affected single-phase inverter includes: After the load power of one of the single-phase inverters decreases, the power reduction of the single-phase inverter is determined based on the initial load power and maximum allowable output power of the single-phase inverter.

5. The method according to claim 4, characterized in that, The dynamic allocation of power adjustment based on the power reduction of the changed single-phase inverter, the maximum allowable output power of the other unchanged single-phase inverters, and the power absorption margin includes: The power reduction should be allocated preferentially to the single-phase inverter with the largest power absorption margin; If the single-phase inverter with the largest power absorption margin cannot fully absorb the power reduction, the power reduction will be allocated according to a proportional weight, wherein the proportional weight is determined by the ratio between the power absorption margins of each single-phase inverter, and the inverter output power of each single-phase inverter after adjustment does not exceed the corresponding maximum allowable output power.

6. The method according to claim 1, characterized in that, Obtaining the local load power and inverter output power of each of the single-phase inverters includes: Each single-phase inverter periodically collects the grid voltage of its phase, the inverter output current of its phase, and the load current of its phase; The inverter output power is obtained based on the grid voltage of this phase and the inverter output current of this phase; The load power of the current phase is obtained based on the grid voltage and the load current of the current phase.

7. A photovoltaic system anti-reverse current control device based on a single-phase inverter, characterized in that, include: Photovoltaic module array; At least two single-phase inverters, wherein the DC input terminal of the single-phase inverter is connected to the photovoltaic module array, and the AC output terminal of the single-phase inverter is connected to the power grid and the load respectively; The single-phase inverter includes: The power detection module is used to collect the local grid voltage, local inverter output current, and local load current of the single-phase inverter. The control unit, connected to the power detection module, is used to determine the local load power and inverter output power of the single-phase inverter based on the data collected by the power detection module, and to determine the maximum allowable output power of the single-phase inverter accordingly, wherein the maximum allowable output power is the maximum power value that the single-phase inverter is allowed to output to prevent reverse current. The communication bus connects the control units of each single-phase inverter and is used to broadcast the local load power, inverter output power and maximum allowable output power of each single-phase inverter to other single-phase inverters in a peer-to-peer communication mode. The control unit is further configured to, when the load power of any single-phase inverter changes, determine the power reduction of the single-phase inverter that has changed and the power absorption margin of each other single-phase inverter that has not changed, wherein the power absorption margin characterizes the output power value that the single-phase inverter can increase to prevent reverse flow in the current state; and dynamically allocate a power adjustment amount based on the power reduction of the single-phase inverter that has changed and the power absorption margin of each other single-phase inverter that has not changed, wherein the power adjustment amount is used to independently adjust the actual inverter output power of each single-phase inverter, and the adjusted actual inverter output power does not exceed the maximum allowable output power.

8. The apparatus according to claim 7, characterized in that, Also includes: Three-phase four-wire circuit breaker; The single-phase inverter is configured to have three units; The AC output phase line terminal of each of the single-phase inverters is respectively connected to the line between the corresponding phase of the power grid and the corresponding phase load; The AC output neutral terminals of each of the single-phase inverters are interconnected and connected together to the neutral terminal of the three-phase four-wire circuit breaker, so that the three single-phase inverters form a Y-type topology.

9. The apparatus according to claim 7, characterized in that, The power detection module includes: The voltage sampling unit is used to collect the local grid voltage of the single-phase inverter; The first current sampling unit is used to collect the local inverter output current of the single-phase inverter. The second current sampling unit is used to collect the local load current of the single-phase inverter.

10. An electronic device, characterized in that, include: Memory, processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the method as described in any one of claims 1-6.

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