Photovoltaic group string wiring module, combiner box and photovoltaic inverter

Abstract

The utility model is applicable to the technical field of photovoltaic power generation, and provides a photovoltaic string wiring module, a combiner box and a photovoltaic inverter, the photovoltaic string wiring module comprises a first switch group and a second switch group, the first switch group comprises a first positive pole switch and a first negative pole switch, the input end of the first positive pole switch is connected with the positive pole of a photovoltaic string, and the input end of the second positive pole switch is connected with the negative pole of the photovoltaic string. The output ends are connected in parallel, the input ends of the first cathode switches are connected with the cathodes of the photovoltaic group strings, the output ends are connected in parallel, the first switch group is connected with the anodes and the cathodes of the same group of photovoltaic group strings, the anodes and the cathodes of one group of photovoltaic group strings are connected to the first switch group, and the second switch group is connected with the anodes or the cathodes of the photovoltaic group strings. The first switch group is connected with a group of photovoltaic group strings, the current flowing in the reverse direction is small, and the damage of the current to the photovoltaic group strings when the photovoltaic group strings are reversely connected is reduced. Therefore, the first switch group replaces an auxiliary switch, the auxiliary switch is omitted, the number of switches is reduced, and the production cost is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of photovoltaic power generation, and in particular relates to a photovoltaic string wiring module, a combiner box and a photovoltaic inverter. Background Art

[0002] Currently, multiple photovoltaic strings in a photovoltaic system are connected in parallel, connected to corresponding circuit breakers, and fed into power converters. These circuit breakers typically include a positive switch for connecting the positive pole of the photovoltaic string and a negative switch for connecting the negative pole of the photovoltaic string. These switches can be manually disconnected or controlled by a controller within the device to disconnect the circuit. When a fault occurs, such as when the positive and negative poles of a photovoltaic string are reversed, the current from the photovoltaic string will flow back into the reversed photovoltaic string, damaging the solar panels within the string. In this case, the circuit breaker must be manually or controlled to disconnect the circuit to minimize damage to the photovoltaic strings caused by reversed connection. However, if most or all photovoltaic strings are connected in reverse, even if the controller disconnects the circuit breaker, the large current flowing back into the photovoltaic strings can still damage the strings.

[0003] Existing technology, to minimize damage to PV strings caused by reverse current when connected, typically requires connecting the positive terminals of up to two PV strings simultaneously to one end of a positive switch, and the negative terminals of up to two PV strings simultaneously to one end of a negative switch. To prevent all PV strings from being reversely connected, potentially causing system power failure or even damaging the strings due to high reverse current, an auxiliary switch is added to the PV system. Consequently, the system requires a large number of switches, resulting in complex wiring and increased overall production costs. Utility Model Content

[0004] The embodiment of the present utility model provides a photovoltaic string wiring module, which aims to reduce the number of switches of the photovoltaic string wiring module, simplify the circuit of the photovoltaic string wiring module, and reduce the production cost of the photovoltaic string wiring module.

[0005] The embodiment of the present invention is implemented as follows: a photovoltaic string connection module is used to connect multiple photovoltaic strings, and the photovoltaic string connection module includes:

[0006] a first switch group, comprising at least one first positive switch and at least one first negative switch, wherein the input end of each first positive switch is used to connect to the positive pole of the photovoltaic string, and the output ends are all connected in parallel; the input end of each first negative switch is used to connect to the negative pole of the photovoltaic string, and the output ends are all connected in parallel; the first switch group is used to connect the positive pole and negative pole of multiple groups of the photovoltaic strings, and the positive pole and negative pole of one group of the photovoltaic strings are both connected to the first switch group;

[0007] The second switch group is used to connect the positive pole or the negative pole of the photovoltaic string.

[0008] Furthermore, the first positive switch is further used to connect the positive poles of multiple groups of photovoltaic strings.

[0009] Furthermore, the first negative electrode switch is further used to connect the negative electrodes of multiple groups of photovoltaic strings.

[0010] Furthermore, the second switch group is configured as at least one second positive switch and at least one second negative switch, the input end of each second positive switch is used to connect the positive poles of multiple groups of photovoltaic strings, and the output end is connected in parallel with the output end of the first positive switch, and the input end of each second negative switch is used to connect the negative poles of multiple groups of photovoltaic strings, and the output end is connected in parallel with the output end of the first negative switch.

[0011] Furthermore, the second switch group is configured as at least one second positive switch or at least one second negative switch.

[0012] Furthermore, one end of a second positive switch is used to connect the positive poles of at least two groups of the photovoltaic strings, and one end of a second negative switch is used to connect the negative poles of at least two groups of the photovoltaic strings.

[0013] Furthermore, the second switch may also be configured as at least one second positive switch or at least one second negative switch.

[0014] Furthermore, the number of photovoltaic strings connected to any one of the second positive switches and any one of the second negative switches in the same group is no more than 2.

[0015] The present invention further provides a combiner box, comprising:

[0016] The aforementioned photovoltaic string wiring module;

[0017] A power converter is connected to the photovoltaic string wiring module.

[0018] Furthermore, the output ends of each of the first positive switches and each of the first negative switches are connected to the power converter, and the output ends of each of the second positive switches and each of the second negative switches are connected to the power converter.

[0019] The present invention also provides a photovoltaic inverter, comprising:

[0020] System power supply;

[0021] The aforementioned combiner box, the system power supply is connected to the combiner box;

[0022] an indicator connected to the system power supply and the combiner box;

[0023] a controller connected to the photovoltaic string connection module, the system power supply, and the indicator, the controller being configured to control the disconnection of the first switch group and the second switch group;

[0024] The first switch group is closed first, and the system power supply is connected to the controller to supply power to the controller.

[0025] Furthermore, the photovoltaic inverter further includes a detection mechanism, which is connected to the controller and the power converter to detect the voltage and current in the photovoltaic string connection module.

[0026] Furthermore, the detection mechanism includes a detector connected to both the power converter and the controller, the detector is used to detect the current and voltage output by the photovoltaic string, and when the first switch group is closed, if the indicator shows normal, the second switch group is closed. When the detector detects that the current and voltage output by the photovoltaic string are abnormal, the detector outputs a feedback signal, and the controller controls the first switch group or the second switch group to disconnect according to the feedback signal.

[0027] In the photovoltaic string wiring module of the present invention, the first switch group is first closed to form a power-on circuit in the first switch group. If the photovoltaic string connected to the first switch group is connected in reverse, the first switch group is disconnected to facilitate maintenance of the photovoltaic string. If the photovoltaic string connected to the first switch group does not have any abnormality, the second switch group is closed. When the string connected to the second switch group is abnormal, the second switch group is disconnected. Since the first switch group is connected to a group of effective photovoltaic strings, the reverse current is small, protecting the photovoltaic string or photovoltaic inverter from damage due to reverse current. Therefore, the first switch group replaces the role of the auxiliary switch, eliminating the need for the auxiliary switch. It can be used as an auxiliary switch or as a circuit breaker similar to the second switch group, reducing the number of switches in the photovoltaic string wiring module, simplifying the circuit of the photovoltaic string wiring module, and reducing the production cost of the photovoltaic string wiring module. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic structural diagram of an embodiment of a photovoltaic string wiring module provided by an embodiment of the present utility model;

[0029] Figure 2 This is a schematic structural diagram of another embodiment of the photovoltaic string wiring module provided by the embodiment of the present utility model;

[0030] Figure 3 This is a schematic structural diagram of another embodiment of the photovoltaic string wiring module provided by the embodiment of the present utility model;

[0031] Figure 4 This is a structural diagram of another embodiment of the photovoltaic string wiring module provided by the embodiment of the present utility model;

[0032] Figure 5 This is a structural diagram of another embodiment of the photovoltaic string wiring module provided by the embodiment of the present utility model;

[0033] Figure 6 This is a structural diagram of a combiner box provided by an embodiment of the present utility model;

[0034] Figure 7 It is a structural diagram of a photovoltaic inverter provided by an embodiment of the utility model.

[0035] Explanation of the reference numerals: 100, first switch group; 110, first positive switch; 120, first negative switch; 200, second switch group; 210, second positive switch; 220, second negative switch; 300, power converter; 400, controller; 500, detector; 600, system power supply; 700, photovoltaic string; 800, indicator. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] In the description of the present invention, it should be understood that the orientation or positional relationship indicated in the description of the direction and positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the described features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0039] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but a person of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0040] When a PV string is reversed, current flows back into the reversed string, potentially damaging the panels within the string. In this case, a circuit breaker must be manually or controlled to disconnect the circuit to minimize damage to the strings. However, if most or all of the strings are reversed, even if the controller disconnects the circuit breaker, the high current flowing back into the strings can still damage them. Existing technologies to minimize damage from reversed string connection typically involve connecting the positive (PV+) terminals of up to two PV strings to one end of a positive switch, and the negative (PV-) terminals of up to two PV strings to one end of a negative switch. To prevent damage to all PV strings caused by reversed connection, an auxiliary switch is also required. Consequently, the system requires a large number of switches, resulting in complex circuitry and increased production costs. To this end, the present application proposes a photovoltaic string wiring module, which aims to reduce the number of switches in the photovoltaic string wiring module, simplify the circuits of the photovoltaic string wiring module, and reduce the production cost of the photovoltaic string wiring module.

[0041] See also Figures 1 to 2 The present invention provides a photovoltaic string connection module for connecting multiple photovoltaic strings 700. The photovoltaic string connection module includes a first switch group 100 and a second switch group 200. The first switch group 100 includes at least one first positive switch 110 and at least one first negative switch 120. The input end of each first positive switch 110 is used to connect to the positive pole of the photovoltaic string 700, and the output ends are all connected in parallel. The input end of each first negative switch 120 is used to connect to the negative pole of the photovoltaic string 700, and the output ends are all connected in parallel. The first switch group 100 is used to connect the positive pole and negative pole of a group of photovoltaic strings 700. The positive pole and negative pole of a group of photovoltaic strings 700 are both connected to the first switch group 100. The second switch group 200 is used to connect to the positive pole or negative pole of the photovoltaic string 700.

[0042] In this way, when the PV string connection module is powered on, the first switch group 100 is first closed. Because the first positive switch 110 and the first negative switch 120 are connected to the positive (PV+) and negative (PV-) poles of the same PV string 700, a power circuit is formed within the first switch group 100. If the positive and negative poles of the PV string 700 connected to the first switch group 100, or all PV strings 700, are reversed, the first switch group 100 is disconnected to facilitate maintenance of the PV strings 700. Because the first switch group 100 connects the positive (PV+) and negative (PV-) poles of the same group of PV strings 700, reverse current flow is minimal, minimizing damage to the PV strings 700 from reverse current flow. In the prior art, to prevent significant damage to the photovoltaic strings 700 when all photovoltaic strings 700 are connected in reverse, an auxiliary switch is added to the photovoltaic string wiring module to determine whether all photovoltaic strings 700 are connected in reverse. However, the auxiliary switch generally does not have the function of disconnecting the photovoltaic string wiring module circuit. Therefore, the first switch group 100 is provided to replace the function of the auxiliary switch and also serves as a circuit breaker similar to the second switch group 200, disconnecting the circuit when the photovoltaic strings 700 are connected in reverse, thereby reducing damage to the photovoltaic strings 700 when the photovoltaic strings 700 are connected in reverse. This eliminates the need for the auxiliary switch, reduces the number of switches in the photovoltaic string wiring module, simplifies the wiring of the photovoltaic string wiring module, and reduces the production cost of the photovoltaic string wiring module.

[0043] Furthermore, the number of positive poles and negative poles of the same photovoltaic strings 700 connected to the first switch group 100 is one group, thereby limiting the number of positive poles (PV+) and negative poles (PV-) from the same photovoltaic strings 700 connected to the first switch group 100, thereby reducing the reverse current when the photovoltaic strings 700 connected to the first switch group 100 are connected in reverse, and weakening the damage to the photovoltaic strings 700 caused by the reverse current when the photovoltaic strings 700 connected to the first switch group 100 or all photovoltaic strings 700 are connected in reverse.

[0044] It is worth mentioning that a circuit breaker is a switching device that can automatically cut off a circuit. It can quickly disconnect the circuit when an abnormal situation such as overload or short circuit occurs in the circuit to protect other devices in the circuit from damage. A set of photovoltaic strings 700 has a positive pole (PV+) and a negative pole (PV-). Figures 1 to 6PVn+ denotes the positive electrode of the Nth photovoltaic string 700, and PVn- denotes the negative electrode of the Nth photovoltaic string 700. In this application, there are at least two or more photovoltaic strings 700, so N is a positive integer not less than 2, and specifically can be 2, 3, 4, 5, 6, or a larger number. The first positive switch 110 and the first negative switch 120 in the first switch group 100 can be the same circuit breakers as the second positive switch 210 and the second negative switch 220 in the second switch group 200, except that they connect to different lines of the photovoltaic strings 700.

[0045] Optionally, in one embodiment, the first positive switch 110 is further configured to connect the positive poles (PV+) of the plurality of photovoltaic strings 700 .

[0046] In this way, the first positive switch 110 is also used to connect the positive poles (PV+) of different groups of photovoltaic strings 700, increasing the number of positive poles (PV+) of photovoltaic strings 700 connected to the first switch group 100. This allows one first positive switch 110 to be connected to multiple groups of photovoltaic strings 700 at the same time, thereby reducing the number of switches and lowering the production cost of the photovoltaic string wiring module.

[0047] Optionally, in one embodiment, the first negative switch 120 is further configured to connect the negative poles (PV-) of the plurality of photovoltaic strings 700 .

[0048] In this way, the first negative pole switch 120 is also used to connect the negative poles (PV-) of different groups of photovoltaic strings 700, increasing the number of negative poles (PV-) of photovoltaic strings 700 connected to the first switch group 100. This allows one first negative pole switch 120 to be connected to multiple groups of photovoltaic strings 700 at the same time, thereby reducing the number of switches and lowering the production cost of the photovoltaic string wiring module.

[0049] Optionally, in one embodiment, one end of a second positive switch 210 is used to connect the positive poles (PV+) of at least two photovoltaic strings 700 , and a second negative switch 220 is used to connect the negative poles (PV-) of at least two photovoltaic strings 700 .

[0050] In this way, one end of a second positive switch 210 is connected to the positive poles (PV+) of at least two photovoltaic strings 700, and one end of a second negative switch 220 is connected to the negative poles (PV-) of at least two photovoltaic strings 700. This allows one second positive switch 210 to be connected to the positive poles (PV+) of multiple photovoltaic strings 700, and one second negative switch 220 to be connected to the negative poles (PV-) of multiple photovoltaic strings 700 at the same time. This reduces the number of switches and thus reduces the production cost of the photovoltaic string connection module.

[0051] Optionally, in one embodiment, the second switch group 200 is configured as at least one second positive switch 210 and at least one second negative switch 220, wherein the input end of each second positive switch 210 is used to connect to the positive pole of multiple photovoltaic strings 700, and the output end is connected in parallel with the output end of the first positive switch 110, and the input end of each second negative switch 220 is used to connect to the negative pole of multiple photovoltaic strings 700, and the output end is connected in parallel with the output end of the first negative switch 120.

[0052] So, see Figures 1 to 2 The second switch group 200 is configured as two or more second positive switches 210 and two or more second negative switches 220, so that the first switch group 100 can be connected to the positive and negative poles of the photovoltaic string 700 to control the current output or disconnection of the photovoltaic string 700.

[0053] Optionally, in another embodiment, the number of the second positive switch 210 and the second negative switch 220 can be set in various ways, see Figures 4 and 5 The second switch group 200 can also be configured as at least one second positive switch 210 or at least one second negative switch 220 .

[0054] In this way, when the second switch group 200 is configured as only a second positive switch 210 or a second negative switch 220, the second switch group 200 is only connected to the positive pole or negative pole of the photovoltaic string 700, so as to reduce the number of disconnect switches and reduce the production cost of the photovoltaic string connection module.

[0055] Optionally, in one embodiment, one end of a second positive switch 210 is used to connect the positive poles of at least two photovoltaic strings 700 , and a second negative switch 220 is used to connect the negative poles of at least two photovoltaic strings 700 .

[0056] In this way, one end of a second positive switch 210 is connected to the positive poles (PV+) of at least two photovoltaic strings 700, and one end of a second negative switch 220 is connected to the negative poles (PV-) of at least two photovoltaic strings 700. This allows one second positive switch 210 to be connected to the positive poles (PV+) of multiple photovoltaic strings 700, and one second negative switch 220 to be connected to the negative poles (PV-) of multiple photovoltaic strings 700 at the same time. This reduces the number of switches and thus reduces the production cost of the photovoltaic string connection module.

[0057] Optionally, in one embodiment, the number of photovoltaic strings 700 connected to any second positive switch 210 and any second negative switch 220 in the same group is no more than two.

[0058] Because the more photovoltaic strings 700 are connected to the same group by a second positive switch 210 and a second negative switch 220, the greater the current flowing through the second positive switch 210 and the second negative switch 220. Therefore, when the photovoltaic strings 700 are connected reversely, the greater the reverse current flowing through the second positive switch 210 and the second negative switch 220. Thus, the number of photovoltaic strings 700 connected to the same group by a second positive switch 210 and a second negative switch 220 is limited to no more than two, specifically one or two groups. This reduces the number of photovoltaic strings 700 connected to the same group by a second positive switch 210 and a second negative switch 220, thereby reducing the reverse current when photovoltaic strings 700 are connected reversely in the second switch group 200 and minimizing damage to the photovoltaic strings 700.

[0059] It is worth mentioning that see Figure 3 The second positive switch 210 in the second switch group 200 can also be used to connect to the negative pole of the photovoltaic string 700, and the second negative switch 220 can also be connected to the positive pole of the photovoltaic string 700. The first positive switch 110 in the first switch group 100 can also be connected to the negative pole of the photovoltaic string 700, and the first negative switch 120 can also be connected to the positive pole of the photovoltaic string 700.

[0060] See also Figure 6 The present invention also provides a combiner box comprising the aforementioned photovoltaic string connection module and a power converter 300, wherein the power converter 300 is connected to the photovoltaic string connection module. The specific structure of the photovoltaic string connection module is similar to that of the aforementioned embodiments. Since the present combiner box utilizes all the technical solutions of all the aforementioned embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the aforementioned embodiments, and therefore will not be further elaborated here.

[0061] Optionally, in one embodiment, the output ends of each first positive switch 110 and each first negative switch 120 are connected to the power converter 300 , and the output ends of each second positive switch 210 and each second negative switch 220 are connected to the power converter 300 .

[0062] In this way, multiple first positive switches 110 and one second positive switch 210 are connected to the power converter 300 to input the current in the photovoltaic string 700 into the power converter 300 in the junction box. The power converter 300 can convert direct current into electricity required for people's daily production and life.

[0063] See also Figure 7The present invention also provides a photovoltaic inverter comprising a system power supply 600, a controller 400, an indicator 800, and the aforementioned combiner box. Each photovoltaic string 700 has a positive electrode (PV+) and a negative electrode (PV-). The multiple photovoltaic strings 700 are connected to a photovoltaic string wiring module in the combiner box. The system power supply 600 is connected to the photovoltaic string wiring module. The indicator 800 is connected to the system power supply 600 and the combiner box. The controller 400 is used to control the disconnection of the second switch group 200 and the first switch group 100. The system power supply 600 is connected to the controller 400 to provide power to the controller 400. The specific structure of the combiner box is similar to the above-mentioned embodiments. Since this photovoltaic inverter adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, and will not be further elaborated here.

[0064] Optionally, in one embodiment, the combiner box further includes a detection mechanism, which is connected to the controller 400 and the power converter 300 to detect the voltage and current in the photovoltaic string connection modules.

[0065] In this way, a detection mechanism is set in the junction box to detect the current and voltage output from the photovoltaic string wiring module to monitor the current and voltage in the junction box, and the controller 400 is connected so that when the detection mechanism detects that the current and voltage output from the string wiring module are abnormal, the controller 400 controls the first switch group 100 or the second switch group 200 to disconnect, thereby improving the system automation of the junction box.

[0066] Optionally, in one embodiment, the detection mechanism includes a detector 500 connected to both the power converter 300 and the controller 400. The detector 500 is used to detect the current and voltage output by the photovoltaic string 700. When the first switch group 100 is closed, if the indicator 800 shows normal, the user closes the second switch group 200. When the detector 500 detects that the current and voltage output by the photovoltaic string 700 are abnormal, the detector 500 outputs a feedback signal. The controller 400 controls the first switch group 100 or the second switch group 200 to disconnect according to the feedback signal.

[0067] In this way, when the photovoltaic string 700 connected to the first switch group 100 or the second switch group 200 is connected reversely, the current and voltage in the photovoltaic string wiring module will be abnormal. Detectors 500 are set in the first switch group 100 and the second switch group 200 to monitor the current and voltage output from the first switch group 100 and the second switch group 200, so that the detector 500 can monitor the first switch group 100 and the second switch group 200 respectively, thereby improving the reliability and accuracy of the detection mechanism in the junction box and being able to detect the current and voltage in the junction box in a timely manner.

[0068] Optionally, in one embodiment, the positive pole (PV+) of a group of photovoltaic strings 700 is connected to at most one second positive switch 210 or one first positive switch 110, and the negative pole (PV-) of a group of photovoltaic strings 700 is connected to at most one second negative switch 220 or one first negative switch 120.

[0069] In this way, the positive pole (PV+) of a photovoltaic string 700 is connected to at most one second positive switch 210 or first positive switch 110, and the negative pole (PV-) of a photovoltaic string 700 is connected to at most one second negative switch 220 or first negative switch 120, so that the circuit of the photovoltaic string connection module can be cut off, thereby improving the stability of equipment operation.

[0070] It is understandable that those skilled in the art can, under the guidance of the above embodiments, combine various implementation methods in the above embodiments to obtain technical solutions of multiple implementation methods.

[0071] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A photovoltaic string connection module, used to connect multiple photovoltaic strings, characterized in that: The photovoltaic string connection module includes: a first switch group, comprising at least one first positive switch and at least one first negative switch, wherein the input end of each first positive switch is used to connect to the positive pole of the photovoltaic string, and the output ends are all connected in parallel; the input end of each first negative switch is used to connect to the negative pole of the photovoltaic string, and the output ends are all connected in parallel; the first switch group is used to connect the positive pole and negative pole of multiple groups of the photovoltaic strings, and the positive pole and negative pole of one group of the photovoltaic strings are both connected to the first switch group; The second switch group is used to connect the positive pole or the negative pole of the photovoltaic string.

2. The photovoltaic string connection module according to claim 1, wherein: The first positive switch is further used to connect the positive poles of multiple groups of photovoltaic strings; Alternatively, the first negative electrode switch is further used to connect the negative electrodes of multiple groups of the photovoltaic strings.

3. The photovoltaic string connection module according to claim 1, wherein: The second switch group is configured as at least one second positive switch and at least one second negative switch, wherein the input end of each second positive switch is used to connect to the positive poles of the plurality of photovoltaic strings, and the output end is connected in parallel with the output end of the first positive switch, and the input end of each second negative switch is used to connect to the negative poles of the plurality of photovoltaic strings, and the output end is connected in parallel with the output end of the first negative switch; Alternatively, the second switch group is configured as at least one second positive switch or at least one second negative switch.

4. The photovoltaic string connection module according to claim 3, wherein: One end of the second positive switch is used to connect the positive poles of at least two groups of the photovoltaic strings, and one end of the second negative switch is used to connect the negative poles of at least two groups of the photovoltaic strings.

5. The photovoltaic string connection module according to claim 4, characterized in that: The number of photovoltaic strings connected to any one of the second positive switches and any one of the second negative switches in the same group is no more than 2.

6. A combiner box, characterized in that: include: The photovoltaic string connection module according to any one of claims 1 to 5; A power converter is connected to the photovoltaic string wiring module.

7. The combiner box according to claim 6, wherein: The output ends of each of the first positive switches and each of the first negative switches are connected to the power converter, and the output ends of each of the second positive switches and each of the second negative switches are connected to the power converter.

8. A photovoltaic inverter, characterized in that: include: System power supply; The combiner box according to any one of claims 6 to 7, wherein the system power supply is connected to the combiner box; an indicator connected to the system power supply and the combiner box; a controller connected to the photovoltaic string connection module, the system power supply, and the indicator, the controller being configured to control the disconnection of the second switch group and the first switch group; The first switch group is closed first, and the system power supply is connected to the controller to supply power to the controller.

9. The photovoltaic inverter according to claim 8, characterized in that: The photovoltaic inverter further includes a detection mechanism, which is connected to the controller and the power converter and is used to detect the voltage and current in the photovoltaic string connection module.

10. The photovoltaic inverter according to claim 9, characterized in that: The detection mechanism includes a detector connected to the power converter and the controller, the detector is used to detect the current and voltage output by the photovoltaic string. When the first switch group is closed, if the indicator shows normal, the second switch group is closed. When the detector detects that the current and voltage output by the photovoltaic string are abnormal, the detector outputs a feedback signal. The controller controls the second switch group or the first switch group to disconnect according to the feedback signal.

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