Anti-countercurrent system and anti-countercurrent photovoltaic power generation system
By configuring switchover devices between photovoltaic modules to detect current flow and cut off reverse current, a photovoltaic string is formed, which solves the safety problem caused by reverse current in photovoltaic modules, achieves efficient and reliable anti-reverse current effect, and reduces power station maintenance costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2026-03-24
AI Technical Summary
In existing technologies, backflow of current between photovoltaic modules can lead to abnormal power generation and accidents such as fires, and existing anti-reverse current solutions are either costly or have low reliability.
A switch is used to detect the current flow direction of the photovoltaic module and disconnect the connection when the current flows in reverse to form a photovoltaic string, preventing current backflow. The system enables rapid installation and removal through electronic switches and bypass diodes.
It effectively prevents backflow between photovoltaic modules, ensures system safety, reduces maintenance costs, improves reliability and cost-effectiveness, and supports the stable operation of the photovoltaic power generation system throughout its entire life cycle.
Smart Images
Figure CN224037086U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of photovoltaic power generation technology, and in particular to an anti-backflow system and an anti-backflow photovoltaic power generation system. Background Technology
[0002] During the installation and use of solar photovoltaic modules, on the one hand, due to improper installation, the number of photovoltaic modules installed between photovoltaic strings may be different under the same MPPT (Max-Power-Point-Tracking) path or under different MPPT paths, resulting in voltage differences. This can lead to current backflow between different photovoltaic strings / modules, causing serious accidents such as abnormal power generation and fires even before the photovoltaic modules are put into use.
[0003] On the other hand, even if different photovoltaic strings are installed with the same number of photovoltaic modules in strict accordance with the specifications, in reality, due to shading, optimizer control and other factors, there will still be a high voltage difference between different photovoltaic strings / modules, which will cause current backflow, resulting in severe overheating and damage to the modules, or even fire accidents.
[0004] Therefore, it is crucial to prevent potential backflow of current, avoid abnormal accidents, and ensure the safety of solar photovoltaic power generation systems. Utility Model Content
[0005] In view of this, embodiments of this application provide an anti-reverse flow system and an anti-reverse flow photovoltaic power generation system to solve at least one problem existing in the background art.
[0006] In a first aspect, embodiments of this application provide an anti-backflow system, the anti-backflow system comprising:
[0007] At least one switch; each switch is connected to a single photovoltaic module so that adjacent photovoltaic modules are connected end-to-end through the switch to form a photovoltaic string and connected to an inverter;
[0008] The circuit breaker is configured to detect the current flow direction of a single photovoltaic module; and when the current flow direction is reversed, it enters a shutdown state to cut off the connection between the single photovoltaic module and the photovoltaic string, and to bypass the power transmission path from the photovoltaic string to the inverter for the single photovoltaic module; and when the current flow direction is normal, it enters a connection state to allow the single photovoltaic module to be connected in series to the photovoltaic string.
[0009] In conjunction with the first aspect, in an alternative implementation,
[0010] The shutdown device includes:
[0011] An electronic switch circuit is configured to switch the circuit breaker to an off state or an on state; the first signal terminal of the electronic switch circuit is connected to the input terminal of the bypass diode circuit and is configured as the first terminal of the circuit breaker; the second signal terminal of the electronic switch circuit is connected to the first power supply terminal of a single photovoltaic module and is configured as the third terminal of the circuit breaker.
[0012] A detection circuit is configured to detect the current flow direction of a single photovoltaic module; a first detection terminal of the detection circuit is connected to the second power supply terminal of the single photovoltaic module and configured as the fourth terminal of the shutdown device; a second detection terminal of the detection circuit is connected to the output terminal of the bypass diode circuit and configured as the second terminal of the shutdown device; wherein the first terminal and the second terminal are used to connect to the power transmission path from the photovoltaic string to the inverter; and
[0013] The bypass diode circuit is configured to conduct unidirectionally between the first terminal and the second terminal, so as to connect the power transmission path of the photovoltaic string and the inverter when the switch is in the off state.
[0014] In conjunction with the first aspect, in an alternative implementation,
[0015] The shutdown device includes at least one of the following:
[0016] The electronic switch circuit includes a first switching device; a first terminal of the first switching device is configured as a first signal terminal of the electronic switch circuit, and a second terminal of the first switching device is configured as a second signal terminal of the electronic switch circuit.
[0017] The detection circuit includes a first current sensor; the first power input terminal of the first current sensor is configured as the first detection terminal of the detection circuit, and the second power input terminal of the first current sensor is configured as the second detection terminal of the detection circuit.
[0018] The bypass diode circuit includes a first diode; the first electrode of the first diode is connected to the first terminal, and the second electrode of the first diode is connected to the second terminal.
[0019] In conjunction with the first aspect, in an alternative implementation,
[0020] The backflow prevention system includes at least one of the following:
[0021] The first shut-off device includes a first switching device, a first current sensor, and a first diode.
[0022] The second shutdown device includes a second switching device, a second current sensor, and a second diode.
[0023] The third shut-off device includes a third switching device, a third current sensor, and a third diode.
[0024] In the case where the second switch and the first switch are connected adjacent to each other on one side, the first terminal of the first switching device is connected to the first electrode of the first diode, the second power input terminal of the second current sensor, and the second electrode of the second diode, respectively; the second terminal of the first switching device is connected to the first power terminal of the first photovoltaic module; the first power input terminal of the first current sensor is connected to the second power terminal of the first photovoltaic module; the second power input terminal of the first current sensor is connected to the second electrode of the first diode and connected to the inverter.
[0025] The first terminal of the second switching device is connected to the first electrode of the second diode, and the second terminal of the second switching device is connected to the first power supply terminal of the second photovoltaic module; the first power input terminal of the second current sensor is connected to the second power supply terminal of the second photovoltaic module.
[0026] When the third switch and the first switch are adjacent to each other on the other side, the first terminal of the third switching device is connected to the first electrode of the third diode, the second power input terminal of the first current sensor, and the second electrode of the first diode, respectively; the second terminal of the third switching device is connected to the first power terminal of the third photovoltaic module; the first power input terminal of the third current sensor is connected to the second power terminal of the third photovoltaic module; the second power input terminal of the third current sensor is connected to the second electrode of the third diode and connected to the inverter.
[0027] The first terminal of the first switching device is connected to the first electrode of the first diode, and the second terminal of the first switching device is connected to the first power supply terminal of the first photovoltaic module; the first power input terminal of the first current sensor is connected to the second power supply terminal of the first photovoltaic module.
[0028] In conjunction with the first aspect, in an alternative implementation,
[0029] The switch is configured to draw power from the photovoltaic modules.
[0030] In conjunction with the first aspect, in an alternative implementation,
[0031] The anti-reverse current system also includes a system platform terminal, which is communicatively connected to each of the circuit breakers, for monitoring the current flow direction of each photovoltaic module and controlling the off and on states of each circuit breaker.
[0032] In conjunction with the first aspect, in an alternative implementation,
[0033] The anti-backflow system also includes a communication base station, which is communicatively connected to the system platform and each of the shut-off devices to transmit communication data and instructions between the system platform and the shut-off devices.
[0034] In conjunction with the first aspect, in an alternative implementation,
[0035] The circuit breaker includes a control device, which is communicatively connected to the system platform and connected to the control terminal of the electronic switch circuit and the signal output terminal of the detection circuit in the circuit breaker, respectively. The device is used to control the circuit breaker to enter a shutdown state or an on state based on the data output by the detection circuit; and / or to transmit the output data to the system platform so that the system platform generates a control command based on the output data and controls the circuit breaker to enter a shutdown state or an on state based on the control command.
[0036] Secondly, embodiments of this application provide an anti-reverse photovoltaic power generation system, the anti-reverse photovoltaic power generation system comprising:
[0037] At least one photovoltaic string circuit; each photovoltaic string circuit is connected in parallel and connected to the inverter through a power transmission path;
[0038] The photovoltaic string circuit includes at least one photovoltaic module and an anti-reverse current system as described in the first aspect;
[0039] The output power of each photovoltaic module is fed into the power transmission path through a single switch in the anti-reverse flow system, so as to form a photovoltaic string that connects adjacent photovoltaic modules end to end through the switch.
[0040] The beneficial effects of the technical solution provided in this application include: This application embodiment configures a switch-off device for each photovoltaic module, and adjacent photovoltaic modules are connected end-to-end through the switch-off devices to form a photovoltaic string. This enables real-time monitoring of the current flow direction of a single photovoltaic module and its adjacent modules, and detects backflow. Therefore, once the current flow of a single photovoltaic module reverses, the switch-off device enters the off state, cutting off the path between the single photovoltaic module and its adjacent modules, cutting off the connection between the single photovoltaic module and the photovoltaic string, and cutting off the backflow path, preventing backflow. This prevents backflow between photovoltaic modules and between photovoltaic strings, avoiding abnormal accidents and ensuring the safety of the solar photovoltaic power generation system. Therefore, it can simultaneously support backflow prevention between photovoltaic modules and photovoltaic strings, achieving backflow prevention during the initial construction of the power station and the series connection of photovoltaic modules. Furthermore, the switch-off device enables rapid installation and disassembly of individual photovoltaic modules, facilitating the maintenance of the photovoltaic power generation system. It also boasts high reliability, simple structural design, and high cost-effectiveness. Furthermore, once the current flow returns to normal, the circuit breaker enters the connected state and automatically resumes power generation; and current detection, reverse current blocking, and automatic recovery can all be automatically controlled by the system without manual intervention, greatly reducing the power station maintenance cost.
[0041] Additional aspects and advantages of the embodiments of this application 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 embodiments of this application. Attached Figure Description
[0042] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, are provided. The drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly show details of those features. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:
[0043] Figure 1 This is a schematic block diagram of Example 1 of the anti-backflow system in this application.
[0044] Figure 2 This is a schematic block diagram of Example 2 of the anti-backflow system in this application.
[0045] Figure 3 This is a schematic diagram illustrating a specific example of the current flow direction in an embodiment of this application;
[0046] Figure 4 This is a schematic block diagram of Example 3 of the anti-backflow system in the embodiments of this application;
[0047] Figure 5This is a schematic block diagram illustrating a specific example of a switch in an embodiment of this application.
[0048] Figure 6 This is a schematic block diagram illustrating a specific example of an anti-reverse photovoltaic power generation system in this application.
[0049] Figure 7 This is a schematic diagram of a specific example of the control device or system platform in the embodiments of this application. Detailed Implementation
[0050] To make the technical solution and beneficial effects of this application more apparent and understandable, a detailed description is provided below by listing specific embodiments. The accompanying drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly show the details of the local features; unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application pertains.
[0051] The embodiments described in this application are not exhaustive, but merely illustrative of some embodiments, and are not intended to limit the scope of protection of this application. Unless otherwise specified, each step in a particular embodiment can be implemented as an independent embodiment, and the steps can be arbitrarily combined. For example, a solution after removing some steps in a particular embodiment can also be implemented as an independent embodiment, and the order of the steps in a particular embodiment can be arbitrarily interchanged. Furthermore, the optional implementation methods in a particular embodiment can be arbitrarily combined; moreover, the embodiments can be arbitrarily combined with each other. For example, some or all steps of different embodiments can be arbitrarily combined, and a particular embodiment can be arbitrarily combined with the optional implementation methods of other embodiments.
[0052] In each embodiment of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of the embodiments are consistent and can be referenced by each other. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.
[0053] The terminology used in the embodiments of this application is for the purpose of describing specific embodiments only and is not intended to limit the scope of this application.
[0054] In the embodiments of this application, unless otherwise stated, elements expressed in the singular form, such as "a," "an," "the," "the," "the," "the," "the," "the," "this," etc., can mean "one and only one," or "one or more," "at least one," etc. For example, when using articles such as "a," "an," "the," etc. in translation, the noun after the article can be understood as either a singular expression or a plural expression.
[0055] In the embodiments of this application, "multiple" refers to two or more.
[0056] In some embodiments, the terms “at least one of”, “one or more”, “a plurality of”, “multiple”, etc., may be used interchangeably.
[0057] The prefixes "first," "second," etc., used in the embodiments of this application are merely for distinguishing different descriptive objects and do not impose restrictions on the position, order, priority, value, or content of the descriptive objects. The description of the descriptive objects is based on the claims or the context of the embodiments, and the use of prefixes should not constitute unnecessary restrictions. For example, the numerical value of the descriptive object is not limited by ordinal numbers and can be one or more. Taking "first device" as an example, the numerical value of "device" can be one or more. Furthermore, the objects modified by different prefixes can be the same or different. For example, if the descriptive object is "device," then "first device" and "second device" can be the same device or different devices, and their types can be the same or different.
[0058] In some embodiments, the term "connection" can refer to the transmission of electrical signals or data between the connected end and the connected end, and can be understood as "electrical connection," "communication connection," etc. A "connection" can be a direct connection between two components, an indirect connection established through other components, a connection within two components, or any other possible form of connection.
[0059] In the process of developing this application, the inventors discovered the following problems in the related technology:
[0060] Currently, to ensure the safety of solar photovoltaic module power generation systems and prevent potential reverse current flow, the following anti-reverse current solutions exist for photovoltaic modules / strings:
[0061] (1) For a single photovoltaic module / photovoltaic string, the voltage on the MOS body diode connected in series with the output terminal of the photovoltaic module / photovoltaic string is monitored to determine whether current backflow occurs, and then other electronic switches are used to cut off the current backflow path to protect the photovoltaic module / photovoltaic string; however, the voltage monitoring and cut-off control process of this scheme is complex and costly.
[0062] (2) For the entire photovoltaic module / photovoltaic string, the traditional high-voltage axial diode is used to cut off the reverse current between different photovoltaic modules / photovoltaic strings; however, this solution has the following problems: the forward voltage drop is too high under normal conditions, which consumes tens of watts of power and generates serious heat, resulting in high power consumption and low reliability.
[0063] Therefore, this application provides an anti-backflow system that can be applied to solar photovoltaic power generation, etc. Figure 1 A schematic block diagram of an example of an anti-backflow system according to an embodiment of this application is shown. As shown in the figure, the anti-backflow system includes:
[0064] At least one switch 101; each switch 101 is connected to a single photovoltaic (PV) module 102 so that adjacent PV modules 102 are connected end to end through the switch 101 to form a photovoltaic string and connected to an inverter.
[0065] The circuit breaker 101 is configured to detect the current flow direction of a single photovoltaic module 102; and when the current flow direction is reversed, it enters a shutdown state to cut off the connection between the single photovoltaic module 102 and the photovoltaic string, so that the single photovoltaic module 102 is bypassed from the power transmission path from the photovoltaic string to the inverter; and when the current flow direction is normal, it enters a connection state to allow the single photovoltaic module 102 to be connected in series to the photovoltaic string.
[0066] Thus, this embodiment of the application configures a switch-off device for each photovoltaic module, and adjacent photovoltaic modules are connected end-to-end through the switch-off devices to form a photovoltaic string. This enables real-time monitoring of the current flow direction of a single photovoltaic module and its adjacent photovoltaic modules, and detects backflow. Therefore, once the current flow of a single photovoltaic module reverses, the switch-off device enters the off state, cutting off the path between the single photovoltaic module and its adjacent photovoltaic modules, cutting off the connection between the single photovoltaic module and the photovoltaic string, and cutting off the backflow path to prevent backflow. This prevents backflow between photovoltaic modules and between photovoltaic strings, avoids abnormal accidents, and ensures the safety of the solar photovoltaic power generation system. Therefore, it can simultaneously support backflow prevention between photovoltaic modules and photovoltaic strings, achieving backflow prevention during the initial stage of power plant construction and the series connection of photovoltaic modules. Furthermore, the switch-off device enables rapid installation and removal of individual photovoltaic modules, facilitating the maintenance of the photovoltaic power generation system. It also boasts high reliability, simple structural design, and high cost-effectiveness. Furthermore, once the current flow returns to normal, the circuit breaker enters the connected state and automatically resumes power generation; and current detection, reverse current blocking, and automatic recovery can all be automatically controlled by the system without manual intervention, greatly reducing the power station maintenance cost.
[0067] In this embodiment, the specific structure of the switch 101 can be configured according to actual needs, and it can have fast switching performance. The series connection of photovoltaic modules can form a photovoltaic string. The number of photovoltaic modules can be N, and the number of photovoltaic strings can be M, where N and M can be natural numbers greater than or equal to 1.
[0068] In some examples, the switch 101 can detect the current flow direction of a single photovoltaic module 102 using a current sensor, or it can be detected by other methods, such as using a magnetic induction sensor, a Hall effect device, etc.
[0069] In other examples, the shut-off device 101 can be switched between a shut-off state and an on state by a controllable switch, such as an electronic switch.
[0070] In an alternative embodiment, the shut-off device 101 includes:
[0071] The electronic switch circuit 11 is configured to switch the circuit breaker 101 to an off state or an on state; the first signal terminal of the electronic switch circuit 11 is connected to the input terminal of the bypass diode circuit 13 and is configured as the first terminal A1 of the circuit breaker 101; the second signal terminal of the electronic switch circuit 11 is connected to the first power supply terminal of the single photovoltaic module 102 and is configured as the third terminal A3 of the circuit breaker 101.
[0072] A detection circuit 12 is configured to detect the current flow direction of a single photovoltaic module 102; the first detection terminal of the detection circuit 12 is connected to the second power supply terminal of the single photovoltaic module 102 and is configured as the fourth terminal A4 of the switch 101; the second detection terminal of the detection circuit 12 is connected to the output terminal of the bypass diode circuit 13 and is configured as the second terminal A2 of the switch 101; wherein, the first terminal A1 and the second terminal A2 are used to connect to the power transmission path from the photovoltaic string to the inverter; and
[0073] The bypass diode circuit 13 is configured to conduct unidirectionally through the first terminal A1 and the second terminal A2, so that when the switch 101 is in the off state, the power transmission path between the photovoltaic string and the inverter is connected.
[0074] In this embodiment, the first power supply terminal of a single photovoltaic module 102 can be a negative power supply terminal, and the second power supply terminal of a single photovoltaic module 102 can be a positive power supply terminal. Furthermore, the photovoltaic string and the inverter's power transmission path are connected via a bypass diode circuit 13. That is, by connecting multiple bypass diode circuits in series in the power transmission path (such as multiple bypass diodes connected in series), high reverse withstand voltage is achieved, preventing breakdown.
[0075] The first terminal A1, the second terminal A2, the third terminal A3, and the fourth terminal A4 of the circuit breaker 101 can be configured as quick-connect interfaces or other types of connection ports. By connecting to the power transmission path through the first terminal A1 and the second terminal A2, and by connecting to the power supply terminals of the photovoltaic modules through the third terminal A3 and the fourth terminal A4 respectively, the photovoltaic modules can be connected to existing photovoltaic strings. This allows for rapid installation, connection, and removal of the photovoltaic modules through the circuit breaker, facilitating the maintenance of the photovoltaic power generation system.
[0076] The detection circuit 12 can use a current sensor or other sensors (such as voltage sensors) to detect the current flow direction of a single photovoltaic module 102, and can be set according to actual needs.
[0077] refer to Figure 1 In one alternative embodiment, the shut-off device 101 includes at least one of the following:
[0078] The electronic switch circuit 11 includes a first switching device S1; the first terminal of the first switching device S1 is configured as the first signal terminal of the electronic switch circuit 11, and the second terminal of the first switching device S1 is configured as the second signal terminal of the electronic switch circuit 11.
[0079] The detection circuit 12 includes a first current sensor U1; the first power input terminal of the first current sensor U1 is configured as the first detection terminal of the detection circuit 12, and the second power input terminal of the first current sensor U1 is configured as the second detection terminal of the detection circuit 12.
[0080] The bypass diode circuit 13 includes a first diode D1; the first terminal of the first diode D1 is connected to the first terminal A1, and the second terminal of the first diode D1 is connected to the second terminal A2.
[0081] In this embodiment of the application, the first terminal of the first diode D1 can be the positive terminal and the second terminal of the first diode D1 can be the negative terminal, but it is not limited to this. The connection method of the positive and negative terminals of the first diode D1 can be determined according to the positive and negative terminals of the PV component.
[0082] It is understandable that the specific circuit structures of the electronic switch circuit 11, the detection circuit 12, and the bypass diode circuit 13 are not limited to this (see reference). Figure 1 The circuit can be configured according to actual needs. For example, the electronic switch circuit 11 may include multiple switching devices connected in series and / or in parallel, or it may also include other devices such as resistors. The detection circuit 12 may also include other devices such as resistors. The bypass diode circuit 13 may include multiple diodes connected in series and / or in parallel, or it may also include other devices such as resistors.
[0083] In this embodiment of the application, the first power input terminal of the first current sensor U1 can be a positive power input terminal or a negative power input terminal; correspondingly, the second power input terminal of the first current sensor U1 can be a negative power input terminal or a positive power input terminal.
[0084] Figure 2 A schematic block diagram of Example 2 of the anti-backflow system in this application is shown. As shown, in an exemplary embodiment, the anti-backflow system includes at least one of the following:
[0085] First shut-off device 1011; First shut-off device 1011 includes first switching device S1, first current sensor U1 and first diode D1;
[0086] The second shut-off device 1012 includes a second switching device S2, a second current sensor U2, and a second diode D2.
[0087] The third shut-off device 1013 includes a third switching device S3, a third current sensor U3, and a third diode D3.
[0088] In the case where the second switch 1012 and the first switch 1011 are connected adjacent to each other on one side, the first terminal of the first switching device S1 is connected to the first electrode of the first diode D1, the second power input terminal of the second current sensor U2, and the second electrode of the second diode D2, respectively; the second terminal of the first switching device S1 is connected to the first power terminal of the first photovoltaic module P1; the first power input terminal of the first current sensor U1 is connected to the second power terminal of the first photovoltaic module P1; the second power input terminal of the first current sensor U1 is connected to the second electrode of the first diode D1 and connected to the inverter.
[0089] The first terminal of the second switching device S2 is connected to the first electrode of the second diode D2, and the second terminal of the second switching device S2 is connected to the first power supply terminal of the second photovoltaic module P2; the first power input terminal of the second current sensor U2 is connected to the second power supply terminal of the second photovoltaic module P2.
[0090] When the third switch 1013 and the first switch 1011 are adjacent to each other on the other side, the first terminal of the third switching device S3 is connected to the first electrode of the third diode D3, the second power input terminal of the first current sensor U1, and the second electrode of the first diode D1, respectively; the second terminal of the third switching device S3 is connected to the first power supply terminal of the third photovoltaic module P3; the first power input terminal of the third current sensor U3 is connected to the second power supply terminal of the third photovoltaic module P3; the second power input terminal of the third current sensor U3 is connected to the second electrode of the third diode D3 and connected to the inverter.
[0091] The first terminal of the first switching device S1 is connected to the first electrode of the first diode D1, and the second terminal of the first switching device S1 is connected to the first power supply terminal of the first photovoltaic module P1; the first power input terminal of the first current sensor U1 is connected to the second power supply terminal of the first photovoltaic module P1.
[0092] In a photovoltaic string formed by connecting adjacent photovoltaic modules 102 end to end through a switch 101, the first switch 1011 can be connected to the second switch 1012 upstream of it, or to the third switch 1013 downstream of it, or to the second switch 1012 upstream of it and the third switch 1013 downstream of it respectively.
[0093] Figure 3 A schematic diagram illustrating a specific example of current flow in an embodiment of this application is shown. As shown, under normal circumstances, photovoltaic modules are connected end-to-end via switchbacks to form a photovoltaic string, ultimately outputting voltage to the inverter input.
[0094] When a reverse current occurs, causing a single photovoltaic module in the photovoltaic string to turn off, the current will follow the... Figure 3 When the inverter is turned off, the current flows through the bypass diode (such as the first diode D1) and connects to other non-turn-off photovoltaic modules in the photovoltaic string. This allows the photovoltaic module to be bypassed from the power transmission path between the photovoltaic string and the inverter, and finally output voltage to the inverter input terminal. Figure 3 The reverse current flow direction is the same as the current flow direction when reverse current occurs. At this time, the photovoltaic module cuts off the connection path with the photovoltaic string through an electronic switch (such as the first switching device S1) to prevent reverse current.
[0095] In the embodiments of this application, the switching devices may include, but are not limited to: MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), normally open relays, other thyristor switches, etc.
[0096] In an alternative embodiment, the switch 101 is configured to obtain power from the photovoltaic module 102.
[0097] In this embodiment, the circuit breaker 101 can draw power from a single photovoltaic module 102 connected to it, simplifying the circuit structure design. Each circuit breaker connects to and draws power from a single photovoltaic module, controls the physical connection between the module and adjacent modules through a built-in electronic switch, monitors the current flow in real time through a built-in current sensor, and maintains the current path of other adjacent modules when the circuit is off.
[0098] Thus, during the power plant construction phase, when photovoltaic modules are connected in series, the modules are not yet connected to the system. Each module is equipped with a shutdown device, and the current sensor built into the shutdown device can monitor the current flow direction of itself and adjacent photovoltaic modules in real time. The switching device built into the shutdown device is in the on state by default; when the current sensor detects reverse current flow, the local control device can immediately control the switching device to open, cutting off the reverse current path and taking necessary local protection actions to prevent backflow between modules. Then, according to the detection cycle set by the local control device, the switching device can be closed to monitor the current flow direction again; if the current flow direction is normal, the switching device switches to the on state; otherwise, it remains in the off state until the current flow direction is normal, and then the switching device is closed.
[0099] Figure 4 A schematic block diagram of Example 3 of the anti-reverse current system in this application is shown. As shown in the figure, the anti-reverse current system also includes a system platform terminal 103, which is communicatively connected to each of the circuit breakers 101, for monitoring the current flow direction of each photovoltaic module 102 and controlling the off-state and on-state of each of the circuit breakers 101.
[0100] In this embodiment, the system platform 103 is mainly used during the photovoltaic string installation and operation phase to monitor the current flow of each photovoltaic module in each photovoltaic string in real time and send a shutdown or shutdown command to the shutdown device 101. For example, the system platform 103 can be a cloud management platform.
[0101] In an exemplary embodiment, when the system platform 103 detects that the current flow of a certain photovoltaic module 102 is reversed, it can issue a shutdown command to control the shutdown devices of all photovoltaic modules in the photovoltaic string where the photovoltaic module 102 is located to be turned off, so that the entire photovoltaic string is disconnected from the inverter and other photovoltaic strings, thereby improving reliability.
[0102] Then, the system platform 103 can issue an activation command according to the set cycle, and at the same time detect whether the current flow has returned to normal. If it has returned to normal, it controls these shutdown devices to switch to the connected state to ensure that the photovoltaic string generates electricity normally; otherwise, it continues to keep the photovoltaic string off to prevent backflow of current from causing abnormalities.
[0103] In an optional embodiment, the anti-backflow system further includes a communication base station 104, which is communicatively connected to the system platform terminal 103 and each of the shutdown devices 101, to transmit communication data and instructions between the system platform terminal 103 and the shutdown devices 101.
[0104] In this embodiment, the communication base station 104 serves as the communication hub between the system platform 103 and the shutdown device 101. Each shutdown device 101 can be an RSD (Rack Scale Design) node. An RSD node can refer to the basic hardware components that constitute a rack computing unit. Each node can include a processor (such as a CPU), memory, local storage, and network interface. The communication base station 104 can receive current sensor output data from the shutdown device 101 and transmit it uplink to the system platform 103; it can also receive real-time control commands from the system platform 103 and send them to the designated shutdown device, ultimately achieving rapid shutdown or shutdown of a single photovoltaic module and / or photovoltaic string.
[0105] The communication method between the system platform 103 and the shutdown device 101 is not limited to communication base station 104, but can also be direct communication interaction, etc.
[0106] Figure 5 A schematic block diagram illustrating a specific example of a shutdown device according to an embodiment of this application is shown. As shown, in an optional embodiment, the shutdown device 101 includes a control device 14, which is communicatively connected to the system platform terminal 103 and connected to the control terminal of the electronic switch circuit 11 in the shutdown device 101 and the signal output terminal of the detection circuit 12 in the shutdown device 101, respectively. The control device 14 is used to control the shutdown device 101 to enter a shutdown state or an on state based on the data output by the detection circuit 12; and / or to transmit the output data to the system platform terminal 103 so that the system platform terminal 103 generates a control command based on the output data and controls the shutdown device 101 to enter a shutdown state or an on state based on the control command.
[0107] Thus, this embodiment of the application detects backflow of current by means of a switch installed on the photovoltaic module and the linkage control at the system platform, cuts off the backflow path, avoids abnormal accidents, and ensures the safety of the solar photovoltaic power generation system. Furthermore, by combining the switch installed on a single photovoltaic module with the system platform, it can cover all stages of power plant construction and operation, addressing backflow caused by voltage differences between photovoltaic modules and strings due to factors such as deployment quantity, optimizers, and shading. It achieves backflow prevention effects in both the initial stage of photovoltaic module series connection during power plant construction and the subsequent operation of the completed power plant.
[0108] In the early stages of power plant construction, during the series connection of modules, a connection switch is configured for each photovoltaic module. The switch detects the current flow direction of adjacent modules through a detection circuit 12 (such as a current sensor). Once reverse current occurs, the switch cuts off its path with the adjacent modules through an electronic switch circuit 11 (such as a switching device) to prevent reverse current from occurring.
[0109] When the power plant is completed and put into operation, if backflow occurs between different photovoltaic strings due to some photovoltaic modules being blocked or the voltage regulation of the optimizer being mismatched, the system platform (such as a cloud management platform) will monitor the current flow of each photovoltaic module in each photovoltaic string in real time. When backflow occurs, the platform will send a shutdown command to the string to cut off all the modules in the string and prevent backflow from occurring.
[0110] Therefore, the embodiments of this application can effectively avoid serious accidents such as voltage mismatch between different photovoltaic strings during the construction phase of a photovoltaic power station, as well as current backflow, abnormal module heating, and fires caused by optimizer regulation, shading, and other factors during operation. Furthermore, installation is simple and convenient; the system can automatically detect and cut off reverse current during power station operation, and automatically resume normal operation after the reverse current fault disappears, requiring no manual intervention throughout the entire process. This significantly reduces the operation and maintenance costs of the power station and ensures stable and reliable operation throughout its entire lifecycle, from the construction and deployment phases to normal operation.
[0111] In this embodiment of the application, the control device 14 may include a processor connected to a memory, which stores instructions. The processor calls the instructions stored in the memory to implement the functions of the control device 14.
[0112] This application also provides an anti-reverse photovoltaic power generation system. Figure 6 A schematic block diagram illustrating a specific example of an anti-reverse photovoltaic power generation system according to an embodiment of this application is shown. As shown, the anti-reverse photovoltaic power generation system includes:
[0113] At least one photovoltaic string circuit 100; each photovoltaic string circuit 100 is connected in parallel and connected to the inverter through a power transmission path;
[0114] The photovoltaic string circuit 100 includes at least one photovoltaic module 102 and an anti-reverse current system as described in the above embodiments;
[0115] The output power of each photovoltaic module 102 is fed into the power transmission path through a single switch 101 in the anti-reverse flow system, so as to form a photovoltaic string that connects adjacent photovoltaic modules 102 end to end through the switch 101.
[0116] Figure 7This diagram illustrates a specific example of a control device or system platform according to an embodiment of this application. As shown, the control device or system platform may include a processor, memory, network interface, display, and input device connected via a system bus. The processor provides computing and control capabilities. The memory may include non-volatile storage media or internal memory. The non-volatile storage media may store an operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The network interface is used for communication with external terminals via a network connection. The display may be a liquid crystal display (LCD) or an e-ink display. The input device may be a touch layer covering the display, or buttons, a trackball, or a touchpad mounted on the casing of the control device or system platform, or an external keyboard, touchpad, or mouse, etc.
[0117] Those skilled in the art will understand that Figure 7 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the control device or system platform on which the present application is applied. The specific control device or system platform may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.
[0118] Any references to memory, storage, database, or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.
[0119] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations included in the claims. Various modifications and changes can be made to the above embodiments without departing from the scope of this disclosure. Similarly, the various technical features of the above embodiments can be arbitrarily combined to form other embodiments of this application that may not be explicitly described. Therefore, the above embodiments only illustrate several implementations of this application and do not limit the scope of protection of this patent application.
Claims
1. A backflow prevention system, characterized in that, The backflow prevention system includes: At least one switch; each switch is connected to a single photovoltaic module so that adjacent photovoltaic modules are connected end-to-end through the switch to form a photovoltaic string and connected to an inverter; The circuit breaker is configured to detect the current flow direction of a single photovoltaic module; and when the current flow direction is reversed, it enters a shutdown state to cut off the connection between the single photovoltaic module and the photovoltaic string, and to bypass the single photovoltaic module from the power transmission path from the photovoltaic string to the inverter; and when the current flow direction is normal, it enters a connection state to allow the single photovoltaic module to be connected in series to the photovoltaic string. The anti-reverse current system also includes a system platform terminal, which is communicatively connected to each of the circuit breakers, for monitoring the current flow direction of each photovoltaic module and controlling the off-state and on-state of each circuit breaker.
2. The anti-backflow system according to claim 1, characterized in that, The shutdown device includes: An electronic switch circuit is configured to switch the circuit breaker to an off state or an on state; the first signal terminal of the electronic switch circuit is connected to the input terminal of the bypass diode circuit and is configured as the first terminal of the circuit breaker; the second signal terminal of the electronic switch circuit is connected to the first power supply terminal of a single photovoltaic module and is configured as the third terminal of the circuit breaker. A detection circuit is configured to detect the current flow direction of a single photovoltaic module; a first detection terminal of the detection circuit is connected to the second power supply terminal of the single photovoltaic module and configured as the fourth terminal of the shutdown device; a second detection terminal of the detection circuit is connected to the output terminal of the bypass diode circuit and configured as the second terminal of the shutdown device; wherein the first terminal and the second terminal are used to connect to the power transmission path from the photovoltaic string to the inverter; and The bypass diode circuit is configured to conduct unidirectionally through the first terminal and the second terminal, so as to connect the power transmission path of the photovoltaic string and the inverter when the switch is in the off state.
3. The anti-backflow system according to claim 2, characterized in that, The shutdown device includes at least one of the following: The electronic switch circuit includes a first switching device; a first terminal of the first switching device is configured as a first signal terminal of the electronic switch circuit, and a second terminal of the first switching device is configured as a second signal terminal of the electronic switch circuit. The detection circuit includes a first current sensor; the first power input terminal of the first current sensor is configured as the first detection terminal of the detection circuit, and the second power input terminal of the first current sensor is configured as the second detection terminal of the detection circuit. The bypass diode circuit includes a first diode; the first electrode of the first diode is connected to the first terminal, and the second electrode of the first diode is connected to the second terminal.
4. The anti-backflow system according to claim 1, characterized in that, The backflow prevention system includes at least one of the following: The first shut-off device includes a first switching device, a first current sensor, and a first diode. The second shutdown device includes a second switching device, a second current sensor, and a second diode. The third shut-off device includes a third switching device, a third current sensor, and a third diode. In the case where the second switch and the first switch are connected adjacent to each other on one side, the first terminal of the first switching device is connected to the first electrode of the first diode, the second power input terminal of the second current sensor, and the second electrode of the second diode, respectively; the second terminal of the first switching device is connected to the first power terminal of the first photovoltaic module; the first power input terminal of the first current sensor is connected to the second power terminal of the first photovoltaic module; the second power input terminal of the first current sensor is connected to the second electrode of the first diode and connected to the inverter. The first terminal of the second switching device is connected to the first electrode of the second diode, and the second terminal of the second switching device is connected to the first power supply terminal of the second photovoltaic module; the first power input terminal of the second current sensor is connected to the second power supply terminal of the second photovoltaic module. When the third switch and the first switch are adjacent to each other on the other side, the first terminal of the third switching device is connected to the first electrode of the third diode, the second power input terminal of the first current sensor, and the second electrode of the first diode, respectively; the second terminal of the third switching device is connected to the first power terminal of the third photovoltaic module; the first power input terminal of the third current sensor is connected to the second power terminal of the third photovoltaic module; the second power input terminal of the third current sensor is connected to the second electrode of the third diode and connected to the inverter. The first terminal of the first switching device is connected to the first electrode of the first diode, and the second terminal of the first switching device is connected to the first power supply terminal of the first photovoltaic module; the first power input terminal of the first current sensor is connected to the second power supply terminal of the first photovoltaic module.
5. The anti-backflow system according to claim 1, characterized in that, The switch is configured to draw power from the photovoltaic modules.
6. The anti-backflow system according to claim 1, characterized in that, The anti-backflow system also includes a communication base station, which is communicatively connected to the system platform and each of the shut-off devices to transmit communication data and instructions between the system platform and the shut-off devices.
7. The anti-backflow system according to claim 6, characterized in that, The circuit breaker includes a control device, which is communicatively connected to the system platform and connected to the control terminal of the electronic switch circuit and the signal output terminal of the detection circuit in the circuit breaker, respectively. The device is used to control the circuit breaker to enter a shutdown state or an on state based on the data output by the detection circuit; and / or to transmit the output data to the system platform so that the system platform generates a control command based on the output data and controls the circuit breaker to enter a shutdown state or an on state based on the control command.
8. A reverse-current photovoltaic power generation system, characterized in that, The anti-reverse photovoltaic power generation system includes: At least one photovoltaic string circuit; each photovoltaic string circuit is connected in parallel and connected to the inverter through a power transmission path; The photovoltaic string circuit includes at least one photovoltaic module and an anti-reverse current system as described in any one of claims 1-7; The output power of each photovoltaic module is fed into the power transmission path through a single switch in the anti-reverse flow system, so as to form a photovoltaic string that connects adjacent photovoltaic modules end to end through the switch.