Anti-countercurrent photovoltaic power generation system

Abstract

The utility model provides an anti-countercurrent photovoltaic power generation system. The anti-countercurrent photovoltaic power generation system comprises a photovoltaic assembly; the input end of the inverter is connected with the output end of the photovoltaic module; the alternating-current relay is provided with a first end, a second end and a control end, the first end is connected with the output end of the inverter, and the second end is connected with an electric load and a grid-connected device; and the anti-countercurrent controller is connected with the control end of the alternating-current relay and the electric load respectively, and is used for preventing countercurrent by disconnecting the alternating-current relay and / or reducing the power of the inverter under the condition that the grid-connected device obtains the electric energy output by the inverter. The utility model has the advantages that the grid-connected device can be monitored in real time to obtain the condition of the output electric energy of the inverter, and the countercurrent phenomenon can be effectively prevented by disconnecting the alternating-current relay and / or reducing the power of the inverter.

Description

Technical Field

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

[0002] Photovoltaic power generation technology, with its photovoltaic panels' photoelectric effect characteristics, can directly convert solar energy into electrical energy. As an environmentally friendly and sustainable energy solution, it has been widely adopted and promoted.

[0003] The operation of photovoltaic power generation systems follows the principles of "user-side grid connection" and "self-consumption," meaning that the electricity generated by the system primarily meets local electricity demand. If the electricity generated by the photovoltaic power generation modules is insufficient to supply the load, the grid connection device will be activated to draw power from the external power grid to supplement it, achieving dual-source power supply.

[0004] However, when the electricity generated by photovoltaic power generation modules far exceeds the load requirements, the excess power is injected into the grid-connected system and subsequently transmitted to the external power grid. This process can cause significant fluctuations in grid voltage and frequency, thereby affecting the stability and reliability of the external power grid's supply to other users. Utility Model Content

[0005] One objective of this invention is to overcome at least one defect in the prior art and provide an anti-reverse photovoltaic power generation system.

[0006] A further objective of this invention is to monitor in real time the grid-connected device's acquisition of inverter output power to prevent reverse current phenomena.

[0007] Another further objective of this invention is to improve the power quality of alternating current, thereby facilitating accurate judgment and control by the anti-reverse current controller.

[0008] Another further objective of this invention is to reduce power generation at the source, in conjunction with measures such as disconnecting AC relays and reducing inverter power, to form a multi-layered anti-reverse current control system.

[0009] Specifically, this utility model provides an anti-reverse photovoltaic power generation system, comprising:

[0010] Photovoltaic modules;

[0011] An inverter, the input of which is connected to the output of the photovoltaic module;

[0012] An AC relay has a first terminal, a second terminal, and a control terminal. The first terminal is connected to the output terminal of the inverter, and the second terminal is connected to the electrical load and the grid connection device.

[0013] An anti-reverse current controller is connected to the control terminal of the AC relay and the electrical load, respectively, and is used to prevent reverse current by disconnecting the AC relay and / or reducing the power of the inverter when the grid-connected device receives electrical energy output from the inverter.

[0014] Alternatively, the anti-reverse photovoltaic power generation system may also include:

[0015] A pre-stage AC filter, the input of which is connected to the output of the inverter, and the output of which is connected to the input of the AC relay.

[0016] Alternatively, the anti-reverse photovoltaic power generation system may also include:

[0017] A post-stage AC filter is provided, the input of which is connected to the output of the AC relay, and the output of which is connected to the electrical load and the grid-connected device.

[0018] Alternatively, the anti-reverse photovoltaic power generation system may also include:

[0019] At least one DC switch, the input terminal of each DC switch being connected to the output terminal of the photovoltaic module, and the output terminal of each DC switch being connected to the input terminal of the inverter.

[0020] Alternatively, the anti-reverse photovoltaic power generation system may also include:

[0021] At least one electromagnetic interference filter is provided, corresponding one-to-one with the DC switch. The input terminal of each electromagnetic interference filter is connected to the output terminal of its corresponding DC switch, and the output terminal of each electromagnetic interference filter is connected to the input terminal of the inverter.

[0022] Alternatively, the anti-reverse photovoltaic power generation system may also include:

[0023] At least one DC-DC converter corresponds one-to-one with the electromagnetic interference filter. The input terminal of each DC-DC converter is connected to the output terminal of its corresponding electromagnetic interference filter, and the output terminal of each DC-DC converter is connected to the input terminal of the inverter.

[0024] Alternatively, the anti-reverse photovoltaic power generation system may also include:

[0025] A DC bus, the input end of which is connected to the output end of each DC-DC converter, and the output end of which is connected to the input end of the inverter, is used to collect the DC power of the photovoltaic modules and provide it to the inverter.

[0026] Optionally, the photovoltaic module includes multiple sets of photovoltaic panels, and the output terminal of each set of photovoltaic panels is connected to the input terminal of one of the DC switches.

[0027] Optionally, the anti-reverse current controller is also connected to each of the DC switches and is used to control one or more DC switches to disconnect when the grid-connected device receives power output from the inverter.

[0028] Alternatively, the anti-reverse photovoltaic power generation system may also include:

[0029] An electricity meter, connected to the second terminal of the AC relay, is used to record current data between the photovoltaic module, the electrical load, and the grid-connected device;

[0030] The anti-backflow controller has a signal acquisition interface, which is connected to the electricity meter and used to acquire current data from the electricity meter.

[0031] This utility model's anti-backflow photovoltaic power generation system, by setting up an anti-backflow controller, can monitor in real time the grid-connected device's acquisition of inverter output power. Once a potential backflow is detected, measures can be quickly taken to disconnect the AC relay to cut off the circuit, or reduce the inverter power to decrease power generation, effectively preventing power backflow, protecting the external power grid and photovoltaic modules, and ensuring stable system operation.

[0032] Furthermore, in this utility model's anti-reverse photovoltaic power generation system, the pre-stage AC filter performs initial processing on the AC power, effectively removing high-frequency harmonic components and improving power quality. The subsequent AC filter then performs more refined filtering, further eliminating residual harmonics and interference, enabling the AC power to reach higher power quality standards, thereby assisting the anti-reverse controller in making accurate judgments and controlling the system.

[0033] Furthermore, in this utility model's anti-reverse photovoltaic power generation system, the anti-reverse controller is also connected to each DC switch. When the grid-connected device receives electrical energy from the inverter output, the controller can control one or more DC switches to disconnect, reducing power generation at the source. This, in conjunction with measures such as disconnecting AC relays and reducing inverter power, constructs a multi-layered anti-reverse control system.

[0034] The above and other objects, advantages and features of this utility model will become more apparent to those skilled in the art from the following detailed description of specific embodiments of this utility model in conjunction with the accompanying drawings. Attached Figure Description

[0035] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0036] Figure 1 This is a schematic structural diagram of an anti-reverse photovoltaic power generation system according to an embodiment of the present invention.

[0037] Figure label:

[0038] 10. Photovoltaic modules; 11. Photovoltaic panels; 20. Inverters; 30. AC relays; 40. Anti-backflow controllers; 41. Signal acquisition interfaces; 51. Pre-stage AC filters; 52. Post-stage AC filters; 53. Electromagnetic interference filters; 61. DC switches; 62. DC-DC converters; 63. DC buses; 70. Electricity meters; 80. Electrical loads; 90. Grid connection devices. Detailed Implementation

[0039] Reference will now be made in detail to embodiments of the present invention, one or more of which are illustrated in the accompanying drawings. The various embodiments provided are intended to explain the present invention and not to limit it. In fact, various modifications and variations to the present invention will be apparent to those skilled in the art without departing from the scope or spirit of the invention. For example, a feature illustrated or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the present invention is intended to cover such modifications and variations within the scope of the appended claims and their equivalents.

[0040] The following reference Figure 1 The present invention describes an anti-reverse photovoltaic power generation system according to an embodiment of the present invention. The terms "inner," "outer," "upper," "lower," "top," "bottom," "lateral," and "longitudinal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the present invention and for simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0041] In the description of this embodiment, it should be understood that the term "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. When a feature "includes or contains" one or more of the features it covers, unless otherwise specifically described, this indicates that other features are not excluded and may be further included.

[0042] In the description of this embodiment, the terms "one embodiment," "some embodiments," "some examples," "one example," 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 this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] This utility model provides an anti-backflow photovoltaic power generation system. Figure 1 This is a schematic structural diagram of an anti-reverse photovoltaic power generation system according to an embodiment of the present invention. Figure 1 As shown, an anti-reverse photovoltaic power generation system generally includes a photovoltaic module 10, an inverter 20, an AC relay 30, and an anti-reverse controller 40.

[0044] The photovoltaic module 10 is mainly used to convert captured solar energy into electrical energy. The input terminal of the inverter 20 is connected to the output terminal of the photovoltaic module 10. The AC relay 30 has a first terminal, a second terminal, and a control terminal. The first terminal is connected to the output terminal of the inverter 20, and the second terminal is connected to the electrical load 80 and the grid-connected device 90. The anti-reverse current controller 40 is connected to the control terminal of the AC relay 30 and the electrical load 80, respectively. It is used to prevent reverse current by disconnecting the AC relay 30 and / or reducing the power of the inverter 20 when the grid-connected device 90 obtains the output power of the inverter 20.

[0045] With the above structure, by setting up an anti-backflow controller 40, the grid-connected device 90 can monitor the power output of the inverter 20 in real time. Once a potential backflow is detected, measures can be taken quickly to disconnect the AC relay 30 to cut off the circuit, or reduce the power of the inverter 20 to reduce power generation, effectively preventing power backflow, protecting the external power grid and photovoltaic modules 10, and ensuring stable system operation.

[0046] In an optional embodiment, the anti-reverse photovoltaic power generation system may further include a pre-stage AC filter 51, the input of which is connected to the output of the inverter 20, and the output of which is connected to the input of the AC relay 30.

[0047] It is understandable that the inverter 20 will inevitably generate a variety of high-frequency harmonic components during the process of converting DC to AC. If these harmonics are not dealt with, they will seriously affect the power quality.

[0048] The pre-stage AC filter 51 in this embodiment addresses this problem by effectively capturing and removing high-frequency harmonic components through its internal filtering circuit structure. The AC power processed by the pre-stage AC filter 51 exhibits a significantly improved waveform, more closely resembling an ideal sine wave, thereby significantly enhancing power quality.

[0049] Furthermore, in order to achieve higher standards of power quality, the anti-reverse photovoltaic power generation system may also include a post-stage AC filter 52, the input of which is connected to the output of the AC relay 30, and the output of which is connected to the electrical load 80 and the grid connection device 90.

[0050] After the AC power is initially processed by the pre-stage AC filter 51, most of the high-frequency harmonic components have been removed. However, some residual harmonics and other subtle interference signals may still remain. The post-stage AC filter 52 can sensitively capture and eliminate these residual harmonics and interferences. The AC power processed by the post-stage AC filter 52 has a significantly improved purity, which can meet the stringent requirements of the electrical load 80 and the grid-connected device 90 for high-quality power.

[0051] Furthermore, high-quality electrical energy provides a solid foundation for the accurate judgment and control of the anti-reverse current controller 40. Stable and clean electrical parameters enable the anti-reverse current controller 40 to more accurately monitor and analyze the power status of the system, thereby taking corresponding control measures more promptly and precisely, effectively preventing the occurrence of reverse current phenomena, and ensuring the stable and efficient operation of the entire anti-reverse current photovoltaic power generation system.

[0052] In one example, the pre-stage AC filter 51 can be an LC filter, also known as an inductor-capacitor filter. The post-stage AC filter 52 can be an active power filter or a higher-order LC filter.

[0053] In an optional embodiment, the anti-reverse photovoltaic power generation system may further include at least one DC switch 61, the input terminal of each DC switch 61 being connected to the output terminal of the photovoltaic module 10, and the output terminal of each DC switch 61 being connected to the input terminal of the inverter 20.

[0054] A DC switch 61 is connected between the photovoltaic module 10 and the inverter 20, facilitating the on / off control of the DC circuit output by the photovoltaic module 10. During system maintenance, repair, or in case of a fault, the photovoltaic module 10 and inverter 20 can be isolated by disconnecting the corresponding DC switch 61, ensuring the safety of maintenance personnel and facilitating rapid fault diagnosis, narrowing down the fault scope, and improving system maintainability. Furthermore, during anti-reverse current operation, if it is necessary to reduce power generation at the source, the power supply to part of the photovoltaic module 10 can be cut off by controlling the DC switch 61, assisting the anti-reverse current controller 40 in achieving more flexible and precise control.

[0055] In an optional embodiment, the anti-reverse photovoltaic power generation system may further include at least one electromagnetic interference filter 53, which corresponds one-to-one with the DC switch 61. The input terminal of each electromagnetic interference filter 53 is connected to the output terminal of its corresponding DC switch 61, and the output terminal of each electromagnetic interference filter 53 is connected to the input terminal of the inverter 20.

[0056] The electromagnetic interference filter 53, corresponding one-to-one with the DC switch 61, can filter out electromagnetic interference signals in the DC circuit. Since the DC power generated by the photovoltaic module 10 may carry electromagnetic interference, this interference can affect the normal operation of the inverter 20 and may even interfere with the signal acquisition and judgment of the anti-reverse current controller 40. The electromagnetic interference filter 53 can purify the DC power, improve the stability and reliability of the inverter 20, ensure that the inverter 20 efficiently and stably converts DC power to AC power, and at the same time ensure that the anti-reverse current controller 40 obtains accurate signals, thereby executing the anti-reverse current control strategy more precisely.

[0057] In an optional embodiment, the anti-reverse photovoltaic power generation system may further include at least one DC-DC converter 62, which corresponds one-to-one with the electromagnetic interference filter 53. The input terminal of each DC-DC converter 62 is connected to the output terminal of its corresponding electromagnetic interference filter 53, and the output terminal of each DC-DC converter 62 is connected to the input terminal of the inverter 20.

[0058] The DC-DC converter 62, corresponding one-to-one with the electromagnetic interference filter 53, can adjust the filtered DC voltage. Different photovoltaic modules 10 may have different output voltages; the DC-DC converter 62 can convert the voltage to the appropriate voltage level required by the inverter 20, improving the system's adaptability to different photovoltaic module 10 configurations, ensuring the inverter 20 always operates in optimal condition, and improving power generation efficiency. During anti-reverse flow operation, the DC-DC converter 62 can also flexibly adjust its output power according to the instructions of the anti-reverse flow controller 40, cooperating with the inverter 20's power adjustment to better achieve the function of preventing power reverse flow.

[0059] In an optional embodiment, the anti-reverse photovoltaic power generation system may further include a DC bus 63, the input terminal of which is connected to the output terminal of each DC-DC converter 62, and the output terminal of the DC bus 63 is connected to the input terminal of the inverter 20, for collecting the DC power of the photovoltaic module 10 and providing it to the inverter 20.

[0060] The DC bus 63 collects the DC power output from multiple DC-DC converters 62 and stably supplies it to the inverter 20. This allows the DC power from different photovoltaic modules 10, after undergoing different processing stages, to be integrated, providing a continuous and stable power input to the inverter 20 and ensuring the stability and continuity of its operation. A stable DC power supply helps the inverter 20 operate efficiently, reducing the reduction in conversion efficiency or failures caused by power fluctuations, and further ensuring the stable operation of the entire anti-reverse photovoltaic power generation system.

[0061] In one optional embodiment, the photovoltaic module 10 includes multiple sets of photovoltaic panels 11, and the output terminal of each set of photovoltaic panels 11 is connected to the input terminal of a DC switch 61.

[0062] The photovoltaic module 10 consists of multiple sets of photovoltaic panels 11, with each set of photovoltaic panels 11 corresponding to a DC switch 61. This design facilitates individual control of different sets of photovoltaic panels 11. During system operation, the number of sets of photovoltaic panels 11 participating in power generation can be flexibly adjusted by controlling different DC switches 61 according to factors such as illumination conditions and power generation efficiency, thereby achieving initial regulation of power generation.

[0063] Preferably, the anti-reverse current controller 40 can be connected to each DC switch 61 and used to control one or more DC switches 61 to disconnect when the grid-connected device 90 receives power output from the inverter 20.

[0064] In the anti-reverse current scenario, when the grid-connected device 90 obtains electrical energy output from the inverter 20, the controller can control one or more DC switches 61 to disconnect, reducing the power generation at the source. This works in conjunction with measures such as disconnecting the AC relay 30 and reducing the power of the inverter 20 to build a multi-level anti-reverse current control system.

[0065] In the embodiment shown in the accompanying drawings of this utility model, the photovoltaic module 10 includes four photovoltaic panels 11, which are divided into two groups. To match these two groups of photovoltaic panels 11, two DC switches 61, two electromagnetic interference filters 53, and two DC-DC converters 62 are configured respectively. Each group of photovoltaic panels 11 shares one DC switch 61, one electromagnetic interference filter 53, and one DC-DC converter 62. The two groups of photovoltaic panels 11 output electrical energy to the DC bus 63 through their respective DC-DC converters 62. The DC bus 63 acts as an energy collection point, integrating the DC power from the four photovoltaic panels 11 and supplying it uniformly to the inverter 20. This configuration not only ensures stable power transmission but also effectively manages the electrical energy generated by the photovoltaic panels 11, providing a continuous and reliable DC power supply to the inverter 20.

[0066] In an optional embodiment, the anti-reverse photovoltaic power generation system may further include a meter 70 connected to the second terminal of an AC relay 30. This connection allows the meter 70 to record current data between the photovoltaic module 10, the electrical load 80, and the grid-connected device 90. The anti-reverse controller 40 has a signal acquisition interface 41 connected to the meter 70 for acquiring current data from the meter 70. Through in-depth analysis of the current data, the anti-reverse controller 40 can quickly determine the current power supply and demand status of the system and whether there is a risk of reverse current.

[0067] Once the anti-reverse current controller 40 detects that the grid-connected device 90 is receiving electrical energy output from the inverter 20, and that this output may cause reverse current, the anti-reverse current controller 40 will immediately take measures. These measures include, but are not limited to: disconnecting the AC relay 30 to cut off the direct connection with the grid-connected device 90, thereby preventing electrical energy from flowing back to the grid; or reducing the power output of the inverter 20 to reduce unnecessary power generation and output, so as to balance the system supply and demand; or even disconnecting part of the DC switch 61 to regulate the power supplied by the photovoltaic panel 11 to the DC bus 63, further controlling the input power of the inverter 20.

[0068] Through the above-mentioned precise and timely control measures, the anti-reverse current controller 40 can effectively ensure that the photovoltaic power generation system can operate stably under any circumstances, which not only protects the safety of the system itself, but also avoids unnecessary impact and interference to the external power grid, thereby realizing the efficient and safe use of electrical energy.

[0069] Therefore, those skilled in the art should recognize that although many exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A photovoltaic power generation system against reverse current, characterized by, The system comprises: a photovoltaic module; an inverter, the input of which is connected to the output of the photovoltaic module; an AC relay, which has a first end, a second end and a control end, the first end is connected to the output of the inverter, the second end is connected to a load and a grid-connected device; a reverse current prevention controller, which is connected to the control end of the AC relay and the load respectively, and is used to prevent reverse current by disconnecting the AC relay and / or reducing the power of the inverter when the grid-connected device obtains the output power of the inverter.

2. The anti-IV light PV power system of claim 1, wherein, Further comprising: a front-stage AC filter, the input of which is connected to the output of the inverter, and the output of which is connected to the input of the AC relay.

3. The anti-IV light PV power system of claim 2, wherein, Further comprising: a rear-stage AC filter, the input of which is connected to the output of the AC relay, and the output of which is connected to the load and the grid-connected device.

4. The anti-ikarus photovoltaic power generation system according to claim 1, characterized by, Further comprising: at least one DC switch, the input of each of which is connected to the output of the photovoltaic module, and the output of each of which is connected to the input of the inverter.

5. The anti-ikarus photovoltaic power generation system according to claim 4, characterized by, Further comprising: at least one electromagnetic interference filter, which corresponds to the DC switch one by one, the input of each of which is connected to the output of the corresponding DC switch, and the output of each of which is connected to the input of the inverter.

6. The anti-ikarus photovoltaic power generation system according to claim 5, characterized by, Further comprising: at least one DC-DC converter, which corresponds to the electromagnetic interference filter one by one, the input of each of which is connected to the output of the corresponding electromagnetic interference filter, and the output of each of which is connected to the input of the inverter.

7. The anti-ikarus photovoltaic power generation system according to claim 6, characterized by, Further comprising: a DC bus, the input of which is connected to the output of each of the DC-DC converters, and the output of which is connected to the input of the inverter, which is used to collect the DC power of the photovoltaic module and provide it to the inverter.

8. The reverse current prevention photovoltaic power generation system according to claim 4, wherein the photovoltaic module comprises a plurality of photovoltaic panels, and the output of each of the photovoltaic panels is connected to the input of one of the DC switches.

9. The reverse current prevention photovoltaic power generation system according to claim 8, wherein the reverse current prevention controller is further connected to each of the DC switches, and is used to control one or more DC switches to be disconnected when the grid-connected device obtains the output power of the inverter.

10. The anti-ikarus photovoltaic power generation system according to claim 1, characterized by, Further comprising: an ammeter, which is connected to the second end of the AC relay, and is used to record the current data between the photovoltaic module and the load and the grid-connected device; the reverse current prevention controller has a signal acquisition interface, which is connected to the ammeter, and is used to acquire current data from the ammeter.

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