Anti-reflux device and photovoltaic power generation system

Abstract

The utility model discloses an anti-reflux device and a photovoltaic power generation system. The anti-reflux device comprises a housing; the electricity meter assembly comprises a first electricity meter assembly and a second electricity meter assembly, the first electricity meter assembly is suitable for being connected with a power grid and the inverter, and the second electricity meter assembly is suitable for being connected with a load and the inverter; and the data acquisition unit is arranged in the shell, the data acquisition unit is connected with the electric meter assembly and the inverter, and the data acquisition unit is used for controlling the output of the inverter. According to the anti-countercurrent device provided by the utility model, the power utilization data of the power grid and the power utilization data of the inverters or the loads can be monitored at the same time, so that the inverters can quickly respond to countercurrent, the countercurrent quantity flowing to the power grid is effectively reduced, and countercurrent prevention can be carried out on a plurality of inverters at the same time.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic power generation technology, and in particular to an anti-backflow device and a photovoltaic power generation system. Background Technology

[0002] In existing technologies, anti-reverse current devices are mainly divided into two types: one type can only prevent reverse current for a single inverter, and the anti-reverse current response is relatively fast, but for power plants with multiple inverters, this type of anti-reverse current device cannot prevent reverse current for each inverter; the other type of anti-reverse current device can prevent reverse current for multiple inverters through a single grid connection point. Although the installation of this type of anti-reverse current device is simple, the anti-reverse current response is slow, and as the number of inverters increases, the anti-reverse current time will become longer and longer, resulting in a larger and larger reverse current amount. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one objective of the present invention is to provide an anti-backflow device that can simultaneously monitor the power consumption data of the power grid, the inverter, or the load, enabling the inverter to respond quickly to backflow, effectively reducing the backflow to the power grid, and can simultaneously prevent backflow for multiple inverters.

[0004] Another objective of this invention is to provide a photovoltaic power generation system that includes the aforementioned anti-backflow device.

[0005] According to a first aspect of the present invention, an anti-backflow device includes: a housing; an electricity meter assembly, the electricity meter assembly including a first electricity meter assembly and a second electricity meter assembly, the first electricity meter assembly being adapted to be connected to a power grid and an inverter, the second electricity meter assembly being adapted to be connected to a load and the inverter; and a data acquisition unit disposed within the housing, the data acquisition unit being connected to the electricity meter assembly and the inverter, and the data acquisition unit being used to control the output of the inverter.

[0006] According to the embodiments of the present invention, the anti-backflow device, by setting a first meter assembly and a second meter assembly, can simultaneously monitor the power consumption data of the power grid and the power consumption data of the inverter or load. Then, it controls the output of the inverter through power control commands, enabling the inverter to quickly respond to backflow and effectively reduce the amount of backflow flowing to the power grid. Furthermore, the anti-backflow device can simultaneously protect multiple inverters from backflow.

[0007] According to some embodiments of the present invention, the first meter assembly includes a first meter and a first current transformer electrically connected, the first meter being disposed inside the housing, the first current transformer being disposed outside the housing, and the first current transformer being adapted to be connected to the power grid and the inverter; the second meter assembly includes a second meter and a second current transformer electrically connected, the second meter being disposed inside the housing, the second current transformer being disposed outside the housing, and the second current transformer being adapted to be connected to the load and the inverter.

[0008] According to some embodiments of the present invention, the anti-backflow device further includes: a terminal assembly, part of which is disposed within the housing. The terminal assembly includes a first terminal and a second terminal. The first meter is electrically connected to the first current transformer through the first terminal, and the second meter is connected to the second current transformer through the second terminal.

[0009] According to some embodiments of the present invention, the terminal assembly further includes: a data acquisition terminal, which is connected to the data acquisition device and to the first electricity meter and the second electricity meter; and a wiring terminal, which is connected to the first electricity meter and the second electricity meter.

[0010] According to some embodiments of the present invention, the terminal assembly further includes a voltage acquisition terminal adapted to be connected to the power grid; the anti-reverse current device includes: a switch disposed within the housing and connected to the voltage acquisition terminal; and a power supply component disposed within the housing and connected to the switch and the data acquisition unit.

[0011] According to some embodiments of the present invention, the first meter, the second meter, and the data acquisition unit are arranged along a first direction; the switch and the power supply unit are located on the same side of the data acquisition unit in a second direction, and the terminal assembly is located on the other side of the data acquisition unit in the second direction, wherein the second direction is perpendicular to the first direction.

[0012] According to some embodiments of the present invention, the housing is provided with a plurality of guide rails, the plurality of guide rails are spaced apart along the second direction, each guide rail extends along the first direction, the plurality of guide rails include a first guide rail, a second guide rail and a third guide rail, the switch and the power supply component are slidably engaged with the first guide rail, the first meter, the second meter and the data acquisition unit are slidably engaged with the second guide rail, and the terminal assembly is slidably engaged with the third guide rail.

[0013] A photovoltaic power generation system according to a second aspect of the present invention includes: an anti-reverse current device, wherein the anti-reverse current device is the same as the anti-reverse current device according to the first aspect of the present invention; a plurality of inverters, wherein the plurality of inverters are connected in series and then connected to the anti-reverse current device; and a power grid, wherein the power grid is connected to the anti-reverse current device.

[0014] According to some embodiments of this utility model, the power grid, the first current transformer, and the plurality of inverters are arranged along a first direction. The housing of the anti-reverse current device is located on one side of the first current transformer in a second direction. The second current transformer and the load are both located on the same side of the first current transformer in the second direction, and the second current transformer is located between the load and the first current transformer. The second direction is perpendicular to the first direction. The current output terminal of the first current transformer faces the power grid, and the current output terminal of the second current transformer faces the load.

[0015] According to some embodiments of this utility model, the power grid, the first current transformer, the second current transformer, and the plurality of inverters are arranged along a first direction. The first current transformer and the second current transformer are located between the power grid and the plurality of inverters, and the second current transformer is located between the first current transformer and the plurality of inverters. The housing and load of the anti-reverse current device are respectively located on both sides of the first current transformer in a second direction. The current output terminal of the first current transformer faces the power grid, and the current output terminal of the second current transformer faces the power grid.

[0016] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of an anti-backflow device according to an embodiment of the present utility model;

[0019] Figure 2 This is a schematic diagram of a terminal assembly according to an embodiment of the present utility model;

[0020] Figure 3 This is a schematic diagram of the housing according to an embodiment of the present utility model;

[0021] Figure 4 This is a schematic diagram of a photovoltaic power generation system according to an embodiment of the present utility model;

[0022] Figure 5 This is a schematic diagram of a photovoltaic power generation system according to another embodiment of the present invention;

[0023] Figure 6 This is a schematic diagram of a photovoltaic power generation system according to another embodiment of the present invention;

[0024] Figure 7 This is a schematic diagram of the photovoltaic power generation system in the reverse current mode according to an embodiment of the present utility model;

[0025] Figure 8 This is a schematic diagram of the phase-reverse flow mode of a photovoltaic power generation system according to an embodiment of the present utility model;

[0026] Figure 9 This is a schematic diagram showing the connection between the anti-backflow device and the inverter according to an embodiment of the present utility model.

[0027] Explanation of reference numerals in the attached figures:

[0028] 100. Backflow prevention device;

[0029] 10. Housing; 11. Wiring port; 20. Meter assembly; 21. First meter assembly; 211. First meter; 212. First current transformer; 2121. Second connecting wire; 22. Second meter assembly; 221. Second meter; 222. Second current transformer; 2221. Fourth connecting wire; 30. Data acquisition unit; 40. Terminal assembly; 41. First terminal; 42. Second terminal; 43. Data acquisition terminal; 44. Wiring terminal; 45. Voltage acquisition terminal; 50. Power supply unit; 51. Switch; 60. Guide rail; 61. First guide rail; 62. Second guide rail; 63. Third guide rail;

[0030] 200. Photovoltaic power generation system;

[0031] 70. Power grid; 71. First connection line; 80. Inverter; 81. RS485 interface; 90. Load; 91. Third connection line. Detailed Implementation

[0032] The embodiments of this utility model are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Figures 1-9 Description of an anti-backflow device 100 according to a first aspect embodiment of the present invention.

[0033] like Figures 1-3As shown, the anti-backflow device 100 according to the first aspect of the present invention includes: a housing 10, an electricity meter assembly 20, and a data acquisition unit 30.

[0034] Specifically, the meter assembly 20 includes a first meter assembly 21 and a second meter assembly 22. The first meter assembly 21 is adapted to be connected to the power grid 70 and the inverter 80, and the second meter assembly 22 is adapted to be connected to the load 90 and the inverter 80. A data acquisition unit 30 is housed within the housing 10. The data acquisition unit 30 is connected to the meter assembly 20 and the inverter 80, and is used to control the output of the inverter 80.

[0035] It should be noted that the first meter assembly 21 and the second meter assembly 22 are used to measure relevant data at their respective connection points. The data acquisition unit 30 is used to receive the relevant data from the first meter assembly 21 and the second meter assembly 22, and to determine the power value that the inverter 80 needs to output through calculation. Then, it controls the output of the inverter 80 through power control commands to prevent the output power of the inverter 80 from being too high, which would cause excess current to flow back to the power grid 70.

[0036] Reference Figure 2 and Figure 3 When the anti-reverse current device 100 is applied to the photovoltaic power generation system 200, the first meter assembly 21 can be used to measure relevant data on the grid 70 side; the second meter assembly 22 can be used to measure relevant data on the inverter 80 generation side or the load 90 side. Optionally, both the first meter assembly 21 and the second meter assembly 22 can have a display screen to display power-related data, such as voltage, current, active / reactive power, power factor, and electrical energy.

[0037] Specifically, refer to Figure 9 When the photovoltaic power generation system 200 has multiple inverters 80, the multiple inverters 80 can be connected in a daisy-chain manner and then connected to the anti-reverse current device 100. In the description of this utility model, "multiple" means two or more. Thus, the anti-reverse current device 100 can perform anti-reverse current control on multiple inverters 80, and at the same time, the anti-reverse current device 100 can synchronously transmit power control commands to multiple inverters 80, enabling the inverters 80 to respond quickly to reverse current and effectively reduce the reverse current flowing to the grid 70.

[0038] According to the embodiment of this utility model, the anti-backflow device 100, by setting a first meter assembly 21 and a second meter assembly 22, can simultaneously monitor the power consumption data of the power grid 70 and the power consumption data of the inverter 80 or the load 90. Then, it controls the output of the inverter 80 through power control commands, enabling the inverter 80 to respond quickly to backflow and effectively reduce the backflow to the power grid 70. Moreover, the anti-backflow device 100 can simultaneously prevent backflow to multiple inverters 80.

[0039] According to some embodiments of the present invention, the first meter assembly 21 includes a first meter 211 and a first current transformer 212 electrically connected. The first meter 211 is disposed inside the housing 10, and the first current transformer 212 is disposed outside the housing 10. The first current transformer 212 is adapted to be connected to the power grid 70 and the inverter 80. The second meter assembly 22 includes a second meter 221 and a second current transformer 222 electrically connected. The second meter 221 is disposed inside the housing 10, and the second current transformer 222 is disposed outside the housing 10. The second current transformer 222 is adapted to be connected to the load 90 and the inverter 80.

[0040] It should be noted that the three-phase connection method can be used between the power grid 70, the inverter 80 and the load 90, and this application does not impose specific restrictions on this.

[0041] By placing the first meter 211 and the second meter 221 inside the housing 10, the space inside the housing 10 is fully utilized, improving the structural compactness of the anti-backflow device 100. The housing 10 can also protect the first meter 211 and the second meter 221, preventing the first meter 211 and the second meter 221 from failing to detect due to interference from external environmental factors.

[0042] Furthermore, by placing the first current transformer 212 and the second current transformer 222 outside the housing 10, operators can flexibly adjust their installation positions according to actual conditions. This allows the anti-backflow device 100 to adapt to various installation environments, thus expanding its applicability. Moreover, it enables the first current transformer 212 and the second current transformer 222 to measure current more accurately, helping to improve the measurement accuracy of the first meter 211 and the second meter 221, ensuring a better anti-backflow effect from the anti-backflow device 100.

[0043] Furthermore, such as Figures 1-5 As shown, the anti-backflow device 100 also includes a terminal assembly 40. Part of the terminal assembly 40 is disposed inside the housing 10. The terminal assembly 40 includes a first terminal 41 and a second terminal 42. The first meter 211 is electrically connected to the first current transformer 212 through the first terminal 41, and the second meter 221 is connected to the second current transformer 222 through the second terminal 42.

[0044] Specifically, both the first current transformer 212 and the second current transformer 222 have two wires. The two wires of the first current transformer 212 are connected to the top and bottom of the first meter 211 respectively through the first terminal 41, so that a current loop is formed between the first current transformer 212 and the first meter 211. The two wires of the second current transformer 222 are connected to the top and bottom of the second meter 221 respectively through the second terminal 42, so that a current loop is formed between the second current transformer 222 and the second meter 221.

[0045] Therefore, by setting the first terminal 41 and the second terminal 42, a reliable electrical connection between the meter and the corresponding current transformer is achieved, ensuring stable signal transmission between the meter and the corresponding current transformer, which helps improve measurement accuracy and thus improves the operational reliability of the anti-backflow device 100. Furthermore, by partially housing the terminal assembly 40 within the housing 10, the integration of the anti-backflow device 100 is further improved, making the overall structure of the anti-backflow device 100 more compact.

[0046] Furthermore, the terminal assembly 40 also includes a data acquisition terminal 43 and a wiring terminal 44. The data acquisition terminal 43 is connected to the data acquisition unit 30, and also to the first meter 211 and the second meter 221. The wiring terminal 44 is connected to both the first meter 211 and the second meter 221.

[0047] In practical implementation, both the first meter 211 and the second meter 221 have interfaces at their bottom. Data acquisition terminals 43 and wiring terminals 44 are connected to the first meter 211 and the second meter 221 through these interfaces. The data acquisition unit 30 communicates with the first meter 211 and the second meter 221 through the data acquisition terminal 43, enabling rapid and accurate data acquisition from both meters. This facilitates real-time monitoring and analysis, ensuring real-time data transmission and improving data timeliness. The first meter 211 and the second meter 221 are connected to an RS485 bus through the wiring terminal 44. The RS485 bus is then connected to the RS485 port of the inverter 80, enabling coordinated operation of the first meter 211 and the second meter 221. This improves the overall performance of the anti-backflow device 100 and ensures the stability of data communication.

[0048] Therefore, the data acquisition unit 30, the first electricity meter 211, the second electricity meter 221, and the inverter 80 are all connected to the same RS485 bus, and the data acquisition and control commands all use the Modbus protocol (serial communication protocol). To distinguish different devices on the same bus, each device has a different Modbus address. The factory default address of the first electricity meter 211 is 101, and the factory default address of the second electricity meter 221 is 102, which cannot be modified.

[0049] According to some embodiments of this utility model, the terminal assembly 40 further includes a voltage acquisition terminal 45, which is adapted to be connected to the power grid 70. In addition, the anti-reverse current device 100 also includes a switch 51 and a power supply unit 50. The switch 51 is disposed within the housing 10 and is connected to the voltage acquisition terminal 45. The power supply unit 50 is disposed within the housing 10 and is connected to the switch 51 and the data acquisition unit 30.

[0050] By connecting the voltage acquisition terminal 45 to the power grid 70, the first meter 211 of the anti-reverse current device 100 can monitor the voltage status of the power grid 70 in real time. Furthermore, the switch 51, located inside the housing 10 and connected to the voltage acquisition terminal 45, allows for timely control of the switch 51 based on the voltage status of the power grid 70, ensuring the normal operation of the voltage acquisition terminal 45. The power supply unit 50, located inside the housing 10 and connected to the switch 51 and the data acquisition unit 30, ensures a stable power supply to the anti-reverse current device 100, improving the operational reliability of the anti-reverse current device 100.

[0051] It should be noted that switch 51 can be an air isolation switch. Switch 51 is in the off state by default when it leaves the factory. After all the connecting wires are connected and all inverters 80 are working normally, switch 51 is flipped up, at which point the anti-backflow device 100 starts to work.

[0052] The power supply unit 50 can use a DC power supply. The upper part of the power supply unit 50 is connected to one phase of the air disconnect switch, which can reduce the output voltage of the power supply unit 50 from 220V to 5V. The lower part of the power supply unit 50 is connected to the DATALOGGER interface (the interface of the data acquisition unit 30) to supply power to the data acquisition unit 30. This application does not impose specific restrictions on this.

[0053] Specifically, such as Figure 3 As shown, the housing 10 has an AC voltage sampling port (POWER INPUT), a first current transformer port (FOR METER 1), a second current transformer port (FOR METER 2), RS485 ports (RS485-1 / RS485-2 / RS485-3 / RS485-4), an Ethernet / antenna port (ETH / ANT), and a data acquisition port (DATALOGGER). The AC voltage sampling port is electrically connected to the voltage acquisition terminal 45, the first current transformer port is electrically connected to the first terminal 41, the second current transformer port is electrically connected to the second terminal 42, the RS485 port is electrically connected to the terminal 44, the Ethernet / antenna port is electrically connected to the power grid, and the data acquisition port is electrically connected to the data acquisition unit 30.

[0054] In some alternative embodiments, such as Figure 1As shown, the first meter 211, the second meter 221, and the data acquisition unit 30 are along a first direction (e.g., Figure 1 The data acquisition unit 30 is arranged in the left-right direction. Switch 51 and power supply 50 are located in the second direction (e.g., in the left-right direction). Figure 1 On the same side of the data acquisition unit 30 in the upper and lower directions, the terminal assembly 40 is located on the other side of the data acquisition unit 30 in the second direction, which is perpendicular to the first direction.

[0055] For example, in Figure 1 In the example, the width direction of the housing 10 (e.g., Figure 1 The first direction is defined as the left-right direction within the housing 10. The first meter 211, the second meter 221, and the data acquisition unit 30 are arranged within the housing 10 along its width. The height direction of the housing 10 (e.g., the left-right direction) is defined as the first direction. Figure 1 The vertical direction in the middle is the second direction.

[0056] This arrangement effectively utilizes the space within the housing 10, improving the structural compactness of the anti-backflow device 100. Furthermore, the rational layout of the components makes operation and maintenance more convenient for staff, reducing mutual interference between components. In addition, the arrangement of the first meter 211, the second meter 221, and the data acquisition unit 30 facilitates signal transmission and improves the efficiency of data acquisition and processing.

[0057] According to some embodiments of this utility model, the housing 10 is provided with a plurality of guide rails 60, which are spaced apart along a second direction. Each guide rail 60 extends along a first direction, and the plurality of guide rails 60 include a first guide rail 61, a second guide rail 62, and a third guide rail 63. The switch 51 and the power supply component 50 are both slidably engaged with the first guide rail 61, the first meter 211, the second meter 221, and the data acquisition unit 30 are all slidably engaged with the second guide rail 62, and the terminal assembly 40 is slidably engaged with the third guide rail 63.

[0058] For example, in Figure 1 In the example, there are 3 guide rails 60, which are arranged at intervals along the height direction of the housing 10. The 3 guide rails 60 are the first guide rail 61, the second guide rail 62 and the third guide rail 63, with the second guide rail 62 located between the first guide rail 61 and the third guide rail 63.

[0059] The arrangement of multiple guide rails 60 allows for easier installation of components such as the first meter 211, the second meter 221, the data acquisition unit 30, and the terminal assembly 40 onto their respective guide rails 60. This simplifies and simplifies the installation process. Furthermore, the sliding fit between each component and its corresponding guide rail 60 allows for flexible selection of installation positions, improving the accuracy of component placement and enhancing the overall assembly precision of the anti-backflow device 100. Additionally, the spacing of the multiple guide rails 60 along the second direction provides space for wiring, resulting in a neater and more orderly wiring layout and preventing interference between the components' wiring.

[0060] The anti-backflow device 100 according to this utility model has the following working modes:

[0061] like Figure 7 As shown, when the anti-reverse current device 100 is in the reverse current equalization mode, the anti-reverse current device 100 controls the total power of the grid connection point to prevent reverse current from being generated. The inverter 80 is controlled based on the total power of the three phases of the load 90. When the three phases of the load 90 are different, the reverse current and the power purchase in the three phases of the grid 70 will occur at the same time, but the sum of the three phases of the grid 70 is 0.

[0062] Reference Figure 7 The inverter 80 has a three-phase power of 4500W each, while the load 90 has three-phase power of 4000W, 4500W, and 5000W respectively. The reverse current of the 4000W phase of the grid 70 is 500W, and the power purchase of the 5000W phase of the grid 70 is 500W. The phase corresponding to the 4500W grid 70 remains balanced. Therefore, in the equal-current reverse mode, only the total power of the grid 70 needs to be controlled. When the three phases of the load 90 are unbalanced, there may be single-phase power purchases and sales, which can maximize the output of the inverter 80.

[0063] like Figure 8 As shown, when the anti-reverse current device 100 is in phase reverse current mode, the anti-reverse current device 100 controls each phase at the grid connection point to prevent reverse current from being generated. When the three-phase power of the load 90 is unbalanced, the output power of the inverter 80 will be adjusted according to the single-phase load 90 with the smallest power, and there will be no reverse current in each phase at the control point.

[0064] Reference Figure 8 Inverter 80 has a three-phase power of 4000W each, while load 90 has three-phase power of 4000W, 4500W, and 5000W respectively. The grid 70 has no power purchase / sale on the phase corresponding to the 4000W phase, purchases 500W from the phase corresponding to the 4500W phase, and purchases 1000W from the phase corresponding to the 5000W phase. Therefore, the phase-reverse current mode controls grid 70 to prevent reverse current from occurring in any of its three phases. When the three-phase power of load 90 is unbalanced, grid 70 will purchase more electricity.

[0065] like Figures 4-9 As shown, a photovoltaic power generation system 200 according to a second aspect embodiment of the present invention includes: an anti-reverse current device 100, a plurality of inverters 80, and a power grid 70. Specifically, the anti-reverse current device 100 is the same as the anti-reverse current device 100 according to the first aspect embodiment of the present invention described above. The plurality of inverters 80 are connected in series and then connected to the anti-reverse current device 100. The power grid 70 is connected to the anti-reverse current device 100.

[0066] Reference Figure 9 The inverter 80 furthest from the anti-reverse current device 100 (i.e., the end inverter 80) is provided with an RS485 interface 81, and the other inverters 80 are provided with two RS485 interfaces 81. One of the RS485 interfaces 81 on the inverter 80 closest to the anti-reverse current device 100 is connected to the terminal 44 of the anti-reverse current device 100, and the other RS485 interface 81 is connected to one of the RS485 interfaces 81 on its adjacent inverter 80. Then, the two adjacent inverters 80 are connected in series in sequence to make multiple inverters 80 connected in series.

[0067] It should be noted that when multiple inverters 80 are connected in series, they can support inverters 80 with different power. That is, the power of multiple inverters 80 can be the same or different. This application does not impose specific restrictions on this.

[0068] According to the photovoltaic power generation system 200 of this utility model embodiment, by adopting the above-mentioned anti-reverse flow device 100, multiple inverters 80 can be controlled against reverse flow, which speeds up the anti-reverse flow response speed of the photovoltaic power generation system 200 and effectively reduces the reverse flow to the power grid 70.

[0069] According to some embodiments of the present invention, the power grid 70, the first current transformer 212, and the plurality of inverters 80 are along a first direction (e.g., ...). Figure 5 The anti-backflow device 100 is arranged in the left-right direction, and the housing 10 of the anti-backflow device 100 is located in the second direction (e.g., in the left-right direction). Figure 5 On one side of the grid (vertical direction), the second current transformer 222 and the load 90 are both located on the same side of the first current transformer 212 in the second direction, and the second current transformer 222 is located between the load 90 and the first current transformer 212. The second direction is perpendicular to the first direction. The current output terminal of the first current transformer 212 faces the grid 70, and the current output terminal of the second current transformer 222 faces the load 90.

[0070] Reference Figure 1 and Figure 5The housing 10 of the anti-reverse current device 100 is located above the first current transformer 212 in the second direction. The power grid 70, the first current transformer 212, and the inverter 80 are connected by a first connecting line 71. The current of the first current transformer 212 flows to the power grid 70 through the first connecting line 71. The first current transformer 212 is connected to the first terminal 41 through a second connecting line 2121. A third connecting line 91 is provided on the load 90, and the third connecting line 91 is conductive to the first connecting line 71. The second current transformer 222 is connected to the second terminal 42 through a fourth connecting line 2221. The current of the second current transformer 222 flows to the load 90 through the third connecting line 91.

[0071] The above-described configuration is applicable when a current transformer is installed on the load side. In this configuration, the data acquisition unit 30 can determine whether reverse current or excessive power consumption has occurred based on the data from the first meter 211. If reverse current or excessive power consumption is found, the power consumption of the load 90 is determined based on the detection data from the second meter 221 (load-side data), and control commands are transmitted to the inverter 80 via broadcast to control the inverter 80's output power. This configuration allows for direct determination of the grid 70 and load 90 data from the first meter 211 and the second meter 221, eliminating the need for further calculations of the load 90's power consumption and improving the operating efficiency of the photovoltaic power generation system 200.

[0072] According to other embodiments of the present invention, the power grid 70, the first current transformer 212, the second current transformer 222, and the plurality of inverters 80 are along a first direction (e.g., Figure 4 The current transformers are arranged in a left-right direction (as shown in the image). The first current transformer 212 and the second current transformer 222 are located between the power grid 70 and the multiple inverters 80, and the second current transformer 222 is located between the first current transformer 212 and the multiple inverters 80. The housing 10 and the load 90 of the anti-reverse current device 100 are respectively located in the second direction (e.g., in the image). Figure 4 The current output terminals of the first current transformer 212 and the second current transformer 222 are both facing the power grid 70.

[0073] Reference Figure 1 and Figure 4The housing 10 of the anti-backflow device 100 is located above the first current transformer 212 in the second direction. The power grid 70, the first current transformer 212, and the inverter 80 are connected by a first connecting line 71. The current of the first current transformer 212 flows to the power grid 70 through the first connecting line 71. The first current transformer 212 is connected to the first terminal 41 through a second connecting line 2121. A third connecting line 91 is provided on the load 90, and the third connecting line 91 is connected to the first connecting line 71. The second current transformer 222 is connected to the second terminal 42 through a fourth connecting line 2221. The current of the second current transformer 222 flows to the power grid 70 through the first connecting line 71.

[0074] The above setup is suitable for distribution boxes with multiple loads 90 where current transformers cannot be installed on the load side. In this setup, the data acquisition unit 30 can determine whether reverse current or excessive power consumption has occurred based on the data from the first meter 211. If reverse current or excessive power consumption is found, it calculates the power required by the current load 90 based on the detection data from the second meter 221 (data from the inverter 80's generator side) and transmits control commands to the inverter 80 via broadcast to control the inverter 80's output power. This setup allows direct determination of the power on the grid 70 and the inverter 80's generator side using the detection data from the first meter 211 and the second meter 221. The power of the load 90 is the difference between the power generated by the inverter 80 and the power of the grid 70, simplifying the calculation process and improving the operating efficiency of the photovoltaic power generation system 200. Furthermore, operators can choose different wiring methods based on the actual site conditions, adapting to various installation environments and offering a wide range of applications.

[0075] Of course, in other alternative embodiments, such as Figure 6 As shown, in the photovoltaic power generation system 200, only one meter assembly, namely the first meter assembly 21, can be installed. The power grid 70, the first current transformer 212, and multiple inverters 80 are arranged along the first direction. The first current transformer 212 is located between the power grid 70 and the multiple inverters 80. The housing 10 and the load 90 of the anti-reverse current device 100 are respectively located on both sides of the first current transformer 212 in the second direction. The current output terminal of the first current transformer 212 faces the power grid 70.

[0076] Reference Figure 1 and Figure 6The housing 10 of the anti-backflow device 100 is located above the first current transformer 212 in the second direction. The power grid 70, the first current transformer 212, and the inverter 80 are connected by a first connecting line 71. The current of the first current transformer 212 flows to the power grid 70 through the first connecting line 71. The first current transformer 212 is connected to the first terminal 41 through a second connecting line 2121. A third connecting line 91 is provided on the load 90, and the third connecting line 91 is conductive to the first connecting line 71.

[0077] With this setup, the first meter 211 can be used to determine whether reverse current has occurred or excessive power is being drawn. Then, the total output power of all inverters 80 is collected, and the power consumption of the current load 90 is obtained by subtracting the power value of the first meter 211 from the total power. The control command is then transmitted to the inverter 80 via broadcast to control the output power of the inverter 80. However, this reverse current prevention method is relatively slow.

[0078] Specifically, when the anti-backflow device 100 is applied to the photovoltaic power generation system 200, the anti-backflow steps are as follows:

[0079] S1. When all equipment (the above-mentioned power grid 70, load 90, inverter 80 and anti-reverse current device 100) and wiring are installed correctly, set the anti-reverse current mode of the data acquisition device 30 according to different installation methods, and activate the anti-reverse current function of the anti-reverse current device 100 through the APP.

[0080] S2. Determine whether there is data being transmitted by other tasks on the connection line (e.g., RS485 bus) between the anti-reverse current device 100 and the inverter 80 (to prevent communication interference). If the connection line is idle, start the anti-reverse current task and prohibit other tasks from using the connection line.

[0081] S3. If it is the first time to power on, the active power mode of each inverter 80 is set to 4 through a broadcast command, and then the active power data of the first meter component 21 and the second meter component 22 are collected.

[0082] S4. Determine if three consecutive packet losses have occurred (in network communication, the phenomenon of data packets being partially or completely lost during transmission).

[0083] S5. If the judgment result of step S4 is yes, then limit the output power of all inverters 80 to 0. If an anti-reverse current failure power value is set, then limit the output of inverters 80 according to the set power.

[0084] S5' If the judgment result of step S4 is negative, determine whether reverse current has occurred or whether excessive power has been drawn from the grid 70 by using the active power data of the first meter 211. The judgment criterion can be modified by adjusting the anti-reverse current power parameter of the anti-reverse current device 100. If set to a positive value, reverse current to the grid 70 is allowed; if set to a negative value, more power is allowed to be drawn from the grid 70. Alternatively, an anti-reverse current hysteresis parameter can be set (default 0.3%). When the power of the inverter 80 fluctuates within the hysteresis range, the data acquisition unit 30 will not recalculate the output value of the inverter 80.

[0085] S6. If the judgment result of step S5' is yes, then calculate the output of inverter 80 according to the anti-reverse current mode of anti-reverse current device 100.

[0086] S6' If the judgment result of step S5' is negative, then keep the active power calculated in the previous step unchanged;

[0087] S7. Control commands for inverters 80 are broadcast to each inverter 80 to output according to the calculation results of step S6. After waiting 300ms for the inverter 80 to finish processing the commands, the above connection line is released to allow other tasks to send and receive data.

[0088] In step S5 above, if the anti-reverse current device 100 is set to phase reverse current mode, the output of inverter 80 is calculated based on the phase with the smallest load power. If the anti-reverse current device 100 is set to equal reverse current mode, the output of inverter 80 is calculated based on the sum of the three phase powers. The calculation method is load power / total rated power of inverter 80, resulting in a percentage relative to the rated power.

[0089] In step S6 above, if there is excessive reverse current or power consumption, exceeding the hysteresis range, the power consumption per phase of load 90 is calculated based on the data from the second meter 221 or the current power data of inverter 80. The data acquisition unit 30 selects different calculation methods depending on the installation method.

[0090] If the current output terminal of the first current transformer 212 is oriented towards the power grid 70 and the current output terminal of the second current transformer 222 is oriented towards the power grid 70, then the power of the current load 90 = the power generation side power of the inverter 80 - the power of the power grid 70.

[0091] If the current output terminal of the first current transformer 212 is oriented towards the power grid 70 and the current output terminal of the second current transformer 222 is oriented towards the load 90, the power of the load 90 can be directly obtained.

[0092] If only the first meter 211 is set and the second meter 221 is removed, then the power of the load = the sum of the active power of all inverters 80 - the power of the power grid 70.

[0093] Other configurations and operations of the anti-backflow device 100 and the photovoltaic power generation system 200 according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0094] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0095] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0096] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0097] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A backflow prevention device, characterized in that, include: case; An electricity meter assembly, comprising a first electricity meter assembly and a second electricity meter assembly, wherein the first electricity meter assembly is adapted to be connected to a power grid and an inverter, and the second electricity meter assembly is adapted to be connected to a load and the inverter; A data acquisition unit is disposed within the housing and is connected to the meter assembly and the inverter. The data acquisition unit is used to control the output of the inverter.

2. The anti-backflow device according to claim 1, characterized in that, The first meter assembly includes a first meter and a first current transformer that are electrically connected. The first meter is disposed inside the housing, and the first current transformer is disposed outside the housing. The first current transformer is adapted to be connected to the power grid and the inverter. The second meter assembly includes a second meter and a second current transformer that are electrically connected. The second meter is disposed inside the housing, and the second current transformer is disposed outside the housing. The second current transformer is adapted to be connected to the load and the inverter.

3. The anti-backflow device according to claim 2, characterized in that, Also includes: A terminal assembly, part of which is disposed within the housing, the terminal assembly includes a first terminal and a second terminal, the first meter being electrically connected to the first current transformer via the first terminal, and the second meter being connected to the second current transformer via the second terminal.

4. The anti-backflow device according to claim 3, characterized in that, The terminal assembly also includes: A data acquisition terminal is connected to the data acquisition device and to the first electricity meter and the second electricity meter; A terminal block is provided, which is connected to the first meter and the second meter.

5. The anti-backflow device according to claim 4, characterized in that, The terminal assembly further includes a voltage acquisition terminal, which is adapted to be connected to the power grid; The backflow prevention device includes: A switch, which is located inside the housing, is connected to the voltage acquisition terminal. A power supply unit is disposed within the housing and is connected to the switch and the data acquisition unit.

6. The anti-backflow device according to claim 5, characterized in that, The first electricity meter, the second electricity meter, and the data acquisition device are arranged along a first direction; The switch and the power supply are located on the same side of the data acquisition unit in the second direction, and the terminal assembly is located on the other side of the data acquisition unit in the second direction, which is perpendicular to the first direction.

7. The anti-backflow device according to claim 6, characterized in that, The housing is provided with a plurality of guide rails, which are spaced apart along the second direction. Each guide rail extends along the first direction, and the plurality of guide rails include a first guide rail, a second guide rail, and a third guide rail. The switch and the power supply are both slidably engaged with the first guide rail, the first meter, the second meter and the data acquisition unit are all slidably engaged with the second guide rail, and the terminal assembly is slidably engaged with the third guide rail.

8. A photovoltaic power generation system, characterized in that, include: A backflow prevention device, wherein the backflow prevention device is the backflow prevention device according to any one of claims 1-7; Multiple inverters are connected in series and then connected to the anti-reverse current device; The power grid is connected to the anti-backflow device.

9. The photovoltaic power generation system according to claim 8, characterized in that, The power grid, the first current transformer, and the plurality of inverters are arranged along the first direction. The housing of the anti-reverse current device is located on one side of the first current transformer in the second direction. The second current transformer and the load are both located on the same side of the first current transformer in the second direction, and the second current transformer is located between the load and the first current transformer. The second direction is perpendicular to the first direction. The current output terminal of the first current transformer faces the power grid, and the current output terminal of the second current transformer faces the load.

10. The photovoltaic power generation system according to claim 8, characterized in that, The power grid, the first current transformer, the second current transformer, and the plurality of inverters are arranged along a first direction. The first current transformer and the second current transformer are located between the power grid and the plurality of inverters, and the second current transformer is located between the first current transformer and the plurality of inverters. The housing and load of the anti-reverse current device are respectively located on both sides of the first current transformer in a second direction. The current output terminal of the first current transformer faces the power grid, and the current output terminal of the second current transformer faces the power grid.

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