Arc fault location method, apparatus, and photovoltaic system

Abstract

The embodiment of the application provides a kind of arc fault positioning method, device and photovoltaic system, comprising: the bus electric signal of monitoring direct current bus;When it is determined that arc fault occurs based on bus electric signal, first group group string and second group group string are determined from the photovoltaic group string to be identified based on preset grouping rule;The optimizer in the first group group string is controlled to be turned off;If arc fault is eliminated, the first group group string is determined as new photovoltaic group string to be identified;If arc fault is not eliminated, the second group group string is determined as new photovoltaic group string to be identified;The above grouping step is repeatedly executed until the photovoltaic group string to be identified contains only one photovoltaic group string, and the last photovoltaic group string to be identified is determined as fault group string;The optimizer electric signal corresponding to all optimizers in fault group string is monitored, and the arc fault position where arc fault occurs is determined based on optimizer electric signal.The embodiment of the application can timely and accurately locate the arc fault position in complex photovoltaic system.

Description

Technical Field

[0001] This application belongs to the field of electronic technology, and in particular relates to an arc fault location method, device and photovoltaic system. Background Technology

[0002] Electric arcing can cause energy concentration in photovoltaic systems, generating extremely high temperatures that can easily ignite nearby flammable materials, leading to serious fires. Furthermore, electric arcs can burn out connectors, cables, combiner boxes, and even inverters, causing significant property damage and potentially posing a risk of electric shock. Therefore, when an electric arc fault occurs in a photovoltaic system, it is crucial to accurately locate the fault point and take effective measures to resolve it.

[0003] As photovoltaic systems become increasingly complex, the difficulty of locating arc faults increases, making it imperative to solve the problem of accurately pinpointing arc fault locations within photovoltaic systems. Summary of the Invention

[0004] This application provides an arc fault location method, apparatus, and photovoltaic system, which can solve the problem of accurately locating arc fault points in complex photovoltaic systems.

[0005] In a first aspect, embodiments of this application provide an arc fault location method applied to a photovoltaic system. The photovoltaic system includes an inverter circuit and at least two photovoltaic strings. Each photovoltaic string includes multiple photovoltaic modules and multiple optimizers. The output terminal of each photovoltaic module is connected to the input terminal of the corresponding optimizer. The output terminals of the optimizers in each photovoltaic string are connected in series and then connected to the inverter circuit via a DC bus. The method includes: Monitor the bus electrical signal of the DC bus; When an arc fault is determined to have occurred based on the bus electrical signal, a first group of photovoltaic strings and a second group of photovoltaic strings are determined from the photovoltaic strings to be identified based on a preset grouping rule; the initial photovoltaic strings to be identified include all photovoltaic strings. The optimizer in the first group of strings is turned off; if the arc fault is eliminated, the first group of strings is determined as a new photovoltaic string to be identified; if the arc fault is not eliminated, the second group of strings is determined as a new photovoltaic string to be identified; the process returns to the step of determining the first group of strings and the second group of strings from the photovoltaic strings to be identified based on the preset grouping rules, until the photovoltaic strings to be identified contain only one photovoltaic string, and the last photovoltaic string to be identified is determined as the faulty string; Monitor the optimizer electrical signals corresponding to all optimizers in the fault string, and determine the location of the arc fault based on the optimizer electrical signals.

[0006] In one possible implementation of the first aspect, the optimizer electrical signal includes the optimizer's output current, and determining the location of the arc fault based on the optimizer electrical signal includes: Calculate the difference in output current between two adjacent optimizers in the fault string to obtain multiple current differences; The optimizer corresponding to the current difference value greater than the preset threshold value is determined as the arc fault location.

[0007] In one possible implementation of the first aspect, the step of calculating the difference in output current between two adjacent optimizers in the fault string to obtain multiple current differences includes: Each time the output current of each optimizer in the fault string is sampled, the difference between the output currents of two adjacent optimizers in the fault string is calculated to obtain multiple current differences. The step of determining the location of the arc fault by the optimizer corresponding to the current difference value greater than the preset threshold value includes: Increment the count value of the position counter corresponding to the optimizer for current differences exceeding the preset threshold by 1; When the count value of any position counter is detected to be greater than or equal to a preset position count threshold, the optimizer corresponding to the position counter whose count value is greater than or equal to the preset position count threshold is determined as the arc fault location.

[0008] In one possible implementation of the first aspect, the method further includes: After identifying the faulty cluster, the sampling frequency of the target sampling circuit on the faulty cluster is increased. The target sampling circuit is used to sample the optimizer electrical signal.

[0009] In one possible implementation of the first aspect, the method further includes: Each time a bus electrical signal is sampled, the bus electrical signal is detected based on a preset neural network model to obtain the detection result output by the neural network model; When the detection result indicates that an arc fault has occurred, the count value of the fault counter is incremented by 1; when the detection result indicates that no arc fault has occurred, the count value of the fault counter is decremented by 1. When the count value of the fault counter is greater than or equal to a preset fault count threshold, an arc fault is confirmed to have occurred in the photovoltaic system.

[0010] In one possible implementation of the first aspect, determining the first group of strings and the second group of strings from the photovoltaic strings to be identified based on a preset grouping rule includes: The photovoltaic strings to be identified are sorted according to the size of their string identifiers; The photovoltaic strings to be identified are determined as the first group of strings based on the largest or smallest of the sorted string identifiers, and the remaining photovoltaic strings to be identified are determined as the second group of photovoltaic strings.

[0011] In one possible implementation of the first aspect, the method further includes: The location of the arc fault is reported as fault information to the target terminal.

[0012] Secondly, embodiments of this application provide an arc fault detection device for detecting faults in a photovoltaic system. The photovoltaic system includes an inverter circuit and at least two photovoltaic strings. Each photovoltaic string includes multiple photovoltaic modules and multiple optimizers. The output terminal of each photovoltaic module is connected to the input terminal of the corresponding optimizer. The output terminals of the optimizers in each photovoltaic string are connected in series and then connected to the inverter circuit via a DC bus. The device includes: The monitoring unit is used to monitor the bus electrical signal of the DC bus. The determining unit is used to determine the first group of photovoltaic strings and the second group of photovoltaic strings to be identified based on a preset grouping rule when an arc fault is determined to have occurred based on the bus electrical signal; the initial photovoltaic strings to be identified include all photovoltaic strings. The control unit is used to control the optimizer in the first group of strings to turn off; if the arc fault is eliminated, the first group of strings is determined to be a new photovoltaic string to be identified; if the arc fault is not eliminated, the second group of strings is determined to be a new photovoltaic string to be identified; the process returns to the step of determining the first group of strings and the second group of strings from the photovoltaic strings to be identified based on the preset grouping rules, until the photovoltaic strings to be identified contain only one photovoltaic string, and the last photovoltaic string to be identified is determined to be a faulty string; The positioning unit is used to monitor the optimizer electrical signals corresponding to all optimizers in the fault string, and determine the location of the arc fault based on the optimizer electrical signals.

[0013] Thirdly, this application provides a photovoltaic system, which includes: an inverter circuit and at least two photovoltaic strings. Each photovoltaic string includes multiple photovoltaic modules and multiple optimizers. The output terminal of each photovoltaic module is connected to the input terminal of the corresponding optimizer. The output terminals of the optimizers in each photovoltaic string are connected in series and then connected to the inverter circuit through a DC bus. The photovoltaic system further includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method described in any one of the first aspects above.

[0014] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described in any one of the first aspects above.

[0015] Fifthly, embodiments of this application provide a computer program product that, when run on a terminal device, causes the terminal device to execute the method described in any one of the first aspects above.

[0016] It is understood that the beneficial effects of the second to fifth aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.

[0017] The beneficial effects of this application embodiment compared with the prior art are as follows: This application embodiment is used for arc fault detection in complex photovoltaic systems. The complex photovoltaic system includes an inverter circuit and at least two photovoltaic strings. Each photovoltaic string includes multiple photovoltaic modules and multiple optimizers. The output terminal of each photovoltaic module is connected to the input terminal of the corresponding optimizer. The output terminals of the optimizers in each photovoltaic string are connected in series and then connected to the inverter circuit through a DC bus. The system identifies whether an arc fault has occurred in the photovoltaic system by monitoring the bus electrical signal of the DC bus. When an arc fault occurs, a first group of strings and a second group of strings are determined from the photovoltaic strings to be identified based on a preset grouping rule, and the optimizers in the first group of strings are controlled to be turned off. The system also controls the optimizers in the first group of strings to be turned off. After the circuit breaker is activated, the system monitors whether the arc fault in the photovoltaic system has been eliminated. If the arc fault is eliminated, it indicates that the arc fault is in the first group of photovoltaic strings, not the second group, and the first group of strings is identified as the new photovoltaic string to be identified. If the arc fault is not eliminated, it indicates that the arc fault is in the second group of photovoltaic strings, not the second group, and the second group of strings is identified as the new photovoltaic string to be identified. The above grouping, shutdown, and arc fault monitoring operations are repeated until the photovoltaic string to be identified contains only one photovoltaic string, that is, the arc fault occurs in the last photovoltaic module, and it is identified as the faulty string. After identifying the faulty string, the optimizer electrical signals corresponding to all optimizers in the faulty string are monitored, and the location of the arc fault is determined based on the optimizer electrical signals. In other words, the solution provided in this application can quickly narrow down the range of photovoltaic strings to be identified by controlling the photovoltaic strings to shut down multiple times in groups, combined with the changes in the arc fault signals of the entire photovoltaic system, and then accurately locate the specific fault point for the smallest range of photovoltaic strings to be identified. Therefore, the embodiments of this application can quickly and accurately locate specific arc fault points in complex photovoltaic systems. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a photovoltaic system provided in an embodiment of this application; Figure 2 This is a flowchart illustrating an arc fault location method according to an embodiment of this application; Figure 3 This is a flowchart illustrating an arc fault location method according to another embodiment of this application; Figure 4 This is a flowchart illustrating an arc fault location method according to another embodiment of this application; Figure 5 This is a schematic diagram of the structure of an arc fault location device provided in an embodiment of this application. Detailed Implementation

[0020] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0021] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0022] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0023] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0024] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0026] Figure 1 This is a schematic diagram of the structure of a photovoltaic system provided in an embodiment of this application. The arc fault location method provided in this embodiment can be applied to the arc fault location scenario of this photovoltaic system. Figure 1 As shown, the photovoltaic system 100 includes an inverter circuit 20 and at least two photovoltaic strings 10 (such as photovoltaic string A and photovoltaic string B). Each photovoltaic string 10 includes multiple photovoltaic modules 11 and multiple optimizers 12. The output terminal of each photovoltaic module 11 is connected to the input terminal of the corresponding optimizer 12. The output terminals of the optimizers 12 in each photovoltaic string 10 are connected in series and then connected to the inverter circuit 20 through a DC bus.

[0027] For example, in photovoltaic string A, the output terminal of each photovoltaic module 11 is connected to the input terminal of an optimizer 12. The output terminal of each optimizer 12 includes two terminals, one terminal is connected to the optimizer 12 of the previous photovoltaic module 11, and the other terminal is connected to the optimizer 12 of the next photovoltaic string 11, so that the output terminals of the optimizers 12 in the photovoltaic string 10 are connected in series and then connected to the inverter circuit 20 through the DC bus.

[0028] As an optional embodiment, the photovoltaic system 100 also includes a controller 30, which is connected to the inverter circuit 20 and the photovoltaic string 10 respectively. The controller 30 is used to control each optimizer, such as the on / off state of optimizer 12, or to control the electrical signal of optimizer 12 of the high-frequency sampling optimizer of the target sampling circuit.

[0029] As an example and not a limitation, controller 30 is the control module of the inverter, that is, the inverter includes the controller 30 and the inverter circuit 20.

[0030] For example, the photovoltaic system 100 provided in this embodiment is a hybrid photovoltaic system with "series connection followed by parallel connection". That is, multiple photovoltaic modules 11 are connected in series to form multiple photovoltaic strings 10, which are then connected in parallel to the DC bus and finally connected to the inverter 20 through the DC bus. For this hybrid photovoltaic system 100, arc faults may occur within any string (i.e., series arc) or at the parallel connection point of the strings (i.e., parallel arc). Therefore, when an arc fault occurs in the photovoltaic system 100, locating the arc fault is extremely challenging.

[0031] For example, in some related technologies, the location of an arc fault is determined by judging the difference between the output current of each photovoltaic module 11 and the current of each photovoltaic string 10. However, for this hybrid photovoltaic system 100, the number of photovoltaic strings 10 and photovoltaic modules 11 is very large. Locating the fault location in this way involves a huge number of faults to troubleshoot, resulting in very low efficiency, inability to locate the fault point in a timely manner, inability to quickly implement effective measures, and low safety performance. Moreover, it requires a large amount of computation, necessitates powerful hardware support, and increases equipment costs.

[0032] For example, in a hybrid photovoltaic system, the current of the photovoltaic string 10 is collected at the DC bus. The electrical characteristics of the series arc or the parallel arc at the parallel connection point in any photovoltaic string 10 will be coupled and superimposed, making the signal collected from the inverter circuit 20 extremely complex. Traditional arc fault detection methods can only detect that an arc fault has occurred, but it is difficult to directly analyze and locate it.

[0033] Based on this, embodiments of this application provide an arc fault location method. This method analyzes the bus electrical signals of the DC bus to determine if an arc fault exists in the entire photovoltaic system. It also combines two location methods to quickly pinpoint the specific fault location. For example, firstly, an active switching method is used to quickly locate the photovoltaic string to be identified that is likely to have a fault. Then, the optimizer electrical signals of the photovoltaic string to be identified are analyzed to accurately locate the arc fault location.

[0034] The implementation of the arc fault location method is described in detail below through various embodiments.

[0035] Figure 2 A schematic flowchart of an arc fault location method according to an embodiment of this application is shown. This is an example and not a limitation; the method can be applied to the aforementioned photovoltaic system, including: S201 monitors the bus electrical signal of the DC bus.

[0036] The execution entity in this application embodiment can be an inverter in a photovoltaic system, such as the inverter's controller. That is, the inverter performs arc fault location. Alternatively, it can be a standalone controller or a controller integrated with other devices in the photovoltaic system.

[0037] Please continue to refer to Figure 1 The photovoltaic system 100 includes an inverter circuit 20, at least two photovoltaic strings 10 (such as photovoltaic string A and photovoltaic string B), and a controller 30. Each photovoltaic string 10 includes multiple photovoltaic modules 11 and multiple optimizers 12. The output terminal of each photovoltaic module 11 is connected to the input terminal of the corresponding optimizer 12. The output terminals of the optimizers 12 in each photovoltaic string 10 are connected in series and then connected to the inverter circuit 20 through a DC bus. The inverter circuit 20 is located in the inverter.

[0038] In other words, since each photovoltaic string is connected in parallel to the DC bus, the electrical signals from each photovoltaic string all converge on the DC bus. When an arc fault occurs in a photovoltaic string, the electrical signal from that string flowing into the DC bus carries arc fault-related characteristics, causing the DC bus electrical signal to also carry arc fault-related characteristics. Therefore, by monitoring the DC bus electrical signal, it is possible to determine whether an arc fault has occurred in the entire photovoltaic system.

[0039] As an example, an AFD (Arc Fault Detection Device) can be used to monitor the bus electrical signal of the DC bus and determine whether an arc fault has occurred in the photovoltaic system based on the bus electrical signal. For instance, the AFD can be integrated into the inverter, or the AFD can be connected in series with the DC bus.

[0040] As an example, an AFCI (Arc-Fault Circuit Interrupter) can also be used to monitor the DC bus electrical signal and determine whether an arc fault has occurred in the photovoltaic system based on the bus electrical signal. The AFCI can be integrated into the inverter and monitor the DC bus electrical signal by monitoring the current characteristics passing through the inverter circuit.

[0041] S202, when an arc fault is determined based on the bus electrical signal, the first group of photovoltaic strings and the second group of photovoltaic strings to be identified are determined from the photovoltaic strings to be identified based on the preset grouping rules; the initial photovoltaic strings to be identified include all photovoltaic strings.

[0042] In some embodiments, the preset grouping rule can be to group the photovoltaic strings to be identified by half of the total number of strings each time, that is, to divide them into two groups each time. For example, if the total number is N and N is an even number, then each time the strings are grouped, they can be divided into two groups. That is, the first group has N / 2 photovoltaic strings and the second group also has N / 2 photovoltaic strings. If N is an odd number, then the first group has (N+1) / 2 photovoltaic strings and the second group has (N-1) / 2 photovoltaic strings.

[0043] In some embodiments, the preset grouping rule may be to divide the photovoltaic strings to be identified into several groups on an average basis according to a preset ratio. For example, the first group may have N / 3 photovoltaic strings, and the second group may have 2N / 3 photovoltaic strings.

[0044] In some embodiments, the preset grouping rule may also be to randomly divide the photovoltaic strings to be identified into several groups, and the number of photovoltaic strings contained in each group may be the same or different.

[0045] This application does not limit the number or division method of the preset grouping rules for photovoltaic strings. Using preset grouping rules facilitates subsequent group-based analysis of arc faults, enabling rapid batch screening of photovoltaic strings with arc faults, thus improving fault diagnosis efficiency.

[0046] S203, control the optimizer in the first group of strings to be turned off; if the arc fault is eliminated, determine the first group of strings as the new photovoltaic strings to be identified; if the arc fault is not eliminated, determine the second group of strings as the new photovoltaic strings to be identified; return to the step of determining the first group of strings and the second group of strings from the photovoltaic strings to be identified based on the preset grouping rules, until the photovoltaic strings to be identified contain only one photovoltaic string, and determine the last photovoltaic string to be identified as the fault string.

[0047] When an arc fault is detected based on the bus electrical signal, it is determined that an arc fault has occurred in the photovoltaic system. At this point, arc fault location is required. This embodiment uses a two-stage location method, with different location methods employed at each stage.

[0048] In some embodiments, the first-level positioning uses an active switching method to locate the faulty string. The active switching method refers to the operation of rapid control (such as shutdown) of electronic devices. In the embodiments of this application, by performing a rapid shutdown operation on the optimizer, combined with the changes in the DC bus electrical signal (changes in the arc fault), the string where the arc fault is located is determined.

[0049] For example, to achieve rapid troubleshooting, following the preset grouping rules described above, the optimizer of the first group of strings is first turned off, and the bus voltage signal is acquired after the optimizer is turned off. If an arc fault is determined based on the changes in the bus voltage signal, the first group of strings is identified as the fault group; otherwise, the second group of strings is identified as the fault group. The fault group is then used as a new photovoltaic string to be identified. The preset grouping rules are then used to divide the new photovoltaic string to be identified into two groups, and the optimizer of one group is turned off to identify the fault group, until the fault group is located in a photovoltaic string. This method allows for rapid troubleshooting of faulty strings among a large number of photovoltaic strings, with a fast response speed. Furthermore, by controlling the shutdown of the optimizer, a large amount of computation is not required, reducing hardware requirements.

[0050] Taking a photovoltaic system consisting of 40 photovoltaic strings as an example, the process of locating arc faults in a photovoltaic system is explained: The bus electrical signal of the DC bus is continuously monitored. If an arc fault is determined to have occurred in the photovoltaic system based on the bus electrical signal, then the 40 photovoltaic strings are selected as the photovoltaic strings to be identified.

[0051] Based on preset grouping rules, the first group and the second group are determined from the groups to be identified. For example, channels 1 to 20 are the first group and channels 21 to 40 are the second group. Then, the optimizer in the first group is turned off.

[0052] Scenario 1: The optimizer in the first group of strings is turned off, and the bus voltage signal is acquired after the optimizer is turned off. If the arc fault is determined to be eliminated based on the bus voltage signal, it means that the arc fault occurred in the first group of strings. The first group of strings is then identified as the new photovoltaic strings to be identified, that is, photovoltaic strings 1 to 20 are the photovoltaic strings to be identified. The faulty photovoltaic strings are then checked from the new photovoltaic strings to be identified.

[0053] Based on preset grouping rules, the first and second groups of photovoltaic strings to be identified are determined from the new photovoltaic strings to be identified. For example, strings 1-10 are in the first group, and strings 11-20 are in the second group. The optimizer in the first group is turned off. If the arc fault is determined to be eliminated based on the bus electrical signal, then the first group of strings is determined as the new photovoltaic strings to be identified (same as above), that is, photovoltaic strings 1-10 are the photovoltaic strings to be identified.

[0054] The range of photovoltaic strings to be identified is gradually narrowed down until the photovoltaic strings to be identified contain only one photovoltaic string. The last photovoltaic string to be identified is then identified as the faulty string, which means that the fault can be accurately located to one photovoltaic string.

[0055] Scenario 2: After the optimizer in the first string group is turned off, the bus voltage signal is acquired. If the arc fault is determined based on the bus voltage signal, it indicates that the arc fault occurred in the second string group, and no arc fault occurred in the first string group. The second string group is then identified as the new photovoltaic string to be identified, i.e., photovoltaic strings 21 to 40 are the photovoltaic strings to be identified.

[0056] Continue troubleshooting faulty photovoltaic (PV) strings from the new pool of PV strings to be identified. Based on preset grouping rules, determine the first and second groups of PV strings from the new pool of PV strings to be identified. For example, strings 21-30 are in the first group, and strings 31-40 are in the second group. Control the optimizer in the first group of PV strings to shut down. If the arc fault is determined to be unresolved based on the bus electrical signal, then determine the second group of PV strings as the new pool of PV strings to be identified (same as above), that is, PV strings 31-40 are the PV strings to be identified.

[0057] The range of photovoltaic strings to be identified is gradually narrowed down until the photovoltaic strings to be identified contain only one photovoltaic string. The last photovoltaic string to be identified is then identified as the faulty string, which means that the fault can be accurately located to one photovoltaic string.

[0058] As an example, not a limitation, the preset grouping rule is based on a preset sorting of string identifiers (each photovoltaic string has a corresponding string identifier). Specifically, the strings are sorted according to the size of their string identifiers. The photovoltaic strings with the largest or smallest sorted string identifiers are designated as the first group, and the remaining strings are designated as the second group. For example, if a photovoltaic system includes 40 photovoltaic strings, each with a string identifier from 1 to 40, then photovoltaic strings numbered 1 to 20 are designated as either the first or second group, and similarly, photovoltaic strings numbered 21 to 40 are designated as either the first or second group, thus grouping the photovoltaic strings to be identified.

[0059] In some embodiments, the string identifier may be the device serial number, communication address or other pre-configured identifier of the photovoltaic string, and this application does not limit this.

[0060] S204 monitors the optimizer electrical signals corresponding to all optimizers in the fault string and determines the location of the arc fault based on the optimizer electrical signals.

[0061] After locating the arc fault location to the fault string based on the first-level positioning, the second-level positioning is used to locate the specific arc fault location within the fault string.

[0062] Since a large number of photovoltaic strings have been eliminated through the primary positioning method described above, the secondary positioning only monitors one faulty string. Therefore, the secondary positioning adopts a precise positioning method to accurately locate the specific location of the arc fault. Thus, the secondary positioning method is different from the primary positioning method described above.

[0063] As an example and not a limitation, the optimizer electrical signal includes the optimizer's output current. The difference between the output currents of two adjacent optimizers in the fault string is calculated to obtain multiple current differences. The optimizer corresponding to the current difference greater than a preset threshold is identified as the arc fault location. For example, if the fault string includes photovoltaic module G1, optimizer g1, photovoltaic module G2, optimizer g2, photovoltaic module G3, optimizer g3, photovoltaic module G4, and optimizer g4, the difference between the output currents of optimizer g1 and optimizer g2 is calculated to obtain current difference C1; the difference between the output currents of optimizer g3 and optimizer g4 is calculated to obtain current difference C2. Current differences C1 and C2 are compared with preset thresholds. If current difference C1 is greater than the preset threshold and current difference C2 is less than the preset threshold, then optimizer g1 and its corresponding photovoltaic module G1, and optimizer g2 and its corresponding photovoltaic module G2 are identified as arc fault locations.

[0064] Understandably, the preset threshold value is a pre-set critical value for the difference in output current between two adjacent optimizers connected in series in the same photovoltaic string. That is, when the difference in output current between two adjacent optimizers is less than the preset threshold value, it means that the output current of the optimizer is normal and there is no arc fault. When the difference in output current between two adjacent optimizers is greater than the preset threshold value, it means that the output current of the optimizer is abnormal and there is an arc fault in the optimizer.

[0065] It is understood that the current difference in this example refers to the absolute value of the difference between the output currents of two adjacent optimizers.

[0066] In other examples, the location of the arc fault can also be located by monitoring other optimizer electrical signals, such as output voltage, or a combination of output current and output voltage, etc., which are not limited here.

[0067] As an example, and not a limitation, after determining the location of an arc fault, the location is reported as fault information to the target terminal. The target terminal can then perform corresponding operations based on the arc fault location, such as a safety shutdown operation. It is understood that the target terminal can be the control terminal or the monitoring terminal of the photovoltaic system.

[0068] In some embodiments, the target terminal may also be the back-end system or maintenance terminal of the maintenance personnel (such as the installer) to inform the maintenance personnel of the location of the arc fault, so as to facilitate the maintenance personnel to carry out fault repair.

[0069] In this embodiment, an arc fault detection method is used for a complex photovoltaic system. The complex photovoltaic system includes an inverter circuit and at least two photovoltaic strings. Each photovoltaic string includes multiple photovoltaic modules and multiple optimizers. The output terminal of each photovoltaic module is connected to the input terminal of the corresponding optimizer. The output terminals of the optimizers in each photovoltaic string are connected in series and then connected to the inverter circuit through a DC bus. The method identifies whether an arc fault has occurred in the photovoltaic system by monitoring the bus electrical signal of the DC bus. When an arc fault occurs, a first group of strings and a second group of strings are determined from the photovoltaic strings to be identified based on a preset grouping rule, and the optimizer in the first group of strings is turned off. After turning off the optimizer in the first group of strings, the method monitors the light... If the arc fault in the photovoltaic system has been eliminated, it indicates that the arc fault occurred in the first group of photovoltaic strings, not the second group, and the first group of strings is identified as the new photovoltaic string to be identified. If the arc fault has not been eliminated, it indicates that the arc fault occurred in the second group of photovoltaic strings, not the second group, and the second group of strings is identified as the new photovoltaic string to be identified. The above grouping, shutdown, and arc fault monitoring operations are repeated until the photovoltaic string to be identified contains only one photovoltaic string, that is, the arc fault occurred in the last photovoltaic module, and it is identified as the faulty string. After that, the optimizer electrical signals corresponding to all optimizers in the faulty string are monitored, and the location of the arc fault is determined based on the optimizer electrical signals.

[0070] In other words, the solution provided in this application can quickly narrow down the range of photovoltaic strings to be identified by controlling the shutdown of photovoltaic strings in multiple groups and combining this with the changes in the arc fault signal of the entire photovoltaic system. Then, it can accurately locate the specific fault point by precisely targeting the smallest range of photovoltaic strings to be identified. Therefore, even when applied to complex photovoltaic systems, the solution provided in this application can quickly and accurately locate the specific arc fault point.

[0071] Figure 3 A schematic flowchart of an arc fault location method according to another embodiment of this application is shown. This is an example and not a limitation. Based on the foregoing embodiments, this embodiment describes the specific implementation of the two-stage location method, namely, monitoring the optimizer electrical signals corresponding to all optimizers in the fault string and determining the arc fault location based on the optimizer electrical signals, including: S301: Each time the output current of each optimizer in the fault string is sampled, the difference between the output currents of two adjacent optimizers in the fault string is calculated to obtain multiple current differences.

[0072] In this embodiment, taking the optimizer electrical signal, including the optimizer's output current, as an example, after determining the fault string, the location of the arc fault is determined by the output current corresponding to all optimizers in the fault string.

[0073] This embodiment determines the location of the arc fault by repeatedly sampling the output current of each optimizer in the fault string, thereby improving the accuracy of arc fault location. Specifically, the arc fault location is determined based on the current difference between the output currents of two adjacent optimizers. Therefore, after sampling the output current of each optimizer in the fault string each time, the difference between the output currents of two adjacent optimizers in the fault string is calculated, and the arc fault is located based on the obtained multiple current differences.

[0074] S302, sequentially determine whether each current difference is greater than a preset threshold value; If the current difference is greater than the preset threshold, then execute S303 to increment the count value of the position counter corresponding to the optimizer for the current difference that is greater than the preset threshold by 1.

[0075] If the current difference is less than or equal to the preset threshold, then execute S304 to decrement or clear the count value of the position counter corresponding to the optimizer for the current difference that is less than the preset threshold.

[0076] S305, when the count value of any position counter is detected to be greater than or equal to the preset position count threshold, the optimizer corresponding to the position counter whose count value is greater than or equal to the preset position count threshold is determined as the arc fault location.

[0077] In this embodiment of the application, the specific implementation method of arc fault location based on multiple current differences is as shown in steps S302 to S305.

[0078] As an example, a position counter is associated with each pair of adjacent optimizers. The position counters are used to compare the current difference of the output current of each pair of adjacent optimizers after each sampling with a preset threshold value. The location of the arc fault is then determined based on the count value of the position counters. The count value of the position counters reflects the number of abnormal output currents (current differences greater than the preset threshold value) obtained by each pair of adjacent optimizers after multiple samplings. By determining the number of abnormalities, the location of the arc fault can be improved.

[0079] As an example, a position counter is associated with each optimizer. After each sampling, the current difference of the output current of each pair of adjacent optimizers is compared with a preset threshold. The values ​​of the two position counters corresponding to the pair of adjacent optimizers whose output current exceeds the preset threshold are increased, while the values ​​of the position counters corresponding to other optimizers are decreased. The location of the arc fault is then determined based on the position counter counts. The position counter counts reflect the number of abnormal output currents obtained by each optimizer after multiple samplings (current differences exceeding the preset threshold). Determining the arc fault location by using the number of abnormalities improves the accuracy of arc fault location.

[0080] Taking a faulty string consisting of photovoltaic module G1, optimizer g1, photovoltaic module G2, optimizer g2, photovoltaic module G3, optimizer g3, photovoltaic module G4, and optimizer g4 as an example. Optimizers g1 and g2 are a pair of adjacent optimizers, corresponding to associated position counter w1; optimizers g3 and g4 are a pair of adjacent optimizers, corresponding to associated position counter w2. First, the output currents of optimizers g1, g2, g3, and g4 are acquired. The difference between the output currents of optimizers g1 and g2 is calculated to obtain the current difference C1; the difference between the output currents of optimizers g3 and g4 is calculated to obtain the current difference C2. The current differences C1 and C2 are compared with preset threshold values. If the current difference C1 is greater than the preset threshold value and the current difference C2 is less than the preset threshold value, the count value of position counter w1 is incremented by 1, and the count value of position counter w2 is cleared or decremented by 1.

[0081] The second step involves acquiring the output currents of optimizers g1, g2, g3, and g4. The difference between the output currents of optimizers g1 and g2 is calculated to obtain current difference C3; the difference between the output currents of optimizers g3 and g4 is calculated to obtain current difference C4. Both current differences C3 and C4 are compared to preset thresholds. If current difference C3 is less than the preset threshold, and current difference C4 is greater than the preset threshold, then the count value of position counter w1 is decremented by 1 or cleared to zero, and the count value of position counter w2 is incremented by 1.

[0082] Repeat the above process until the target number of samplings is reached and sampling ends, or until the count value of position counter w1 and / or position counter w2 is greater than or equal to the preset position counting threshold. In this case, the optimizer is determined to be the location of the arc fault by the position counter whose count value is greater than or equal to the preset position counting threshold.

[0083] In some embodiments, when sampling the output current of all optimizers, if the current difference between a pair of adjacent optimizers is greater than a preset threshold, the count value of the corresponding position counter is incremented by 1; if the current difference between the pair of adjacent optimizers is less than or equal to the preset threshold, the count value of the corresponding position counter is decremented by 1. In this way, the number of anomalies (such as current differences greater than the preset threshold) in the comparison results obtained after multiple samplings of the optimizer output current can be counted. If the number of anomalies is high, the optimizer corresponding to that position counter is determined to be at an arc fault location, ensuring the safety performance of the photovoltaic system.

[0084] In some embodiments, when sampling the output circuits of all optimizers, if the current difference between a pair of adjacent optimizers is greater than a preset threshold, the corresponding position counter is incremented by 1; if the current difference between the pair of adjacent optimizers is less than or equal to the preset threshold, the corresponding position counter is reset to zero. By resetting the counter to zero, it is easier to monitor situations where the current difference exceeds the preset threshold multiple times consecutively (i.e., consecutive anomalies), thereby determining that the optimizer corresponding to the position counter where the current difference exceeds the preset threshold multiple times consecutively is at the location of an arc fault, thus improving monitoring accuracy.

[0085] In this embodiment, the obtained current differences are compared with preset threshold values ​​to obtain comparison results. By sampling the output current of each optimizer multiple times, multiple comparison results of each optimizer are obtained. Combining multiple comparison results to determine the location of the arc fault can improve the accuracy of the judgment.

[0086] As an example, after identifying the fault cluster, the sampling frequency of the target sampling circuit on the fault cluster is increased. The target sampling circuit is used to sample the optimizer electrical signal. High-frequency sampling of the optimizer electrical signal can improve fault location efficiency and obtain more accurate transient changes in the optimizer electrical signal.

[0087] Figure 4 A schematic flowchart of an arc fault location method according to another embodiment of this application is shown. This is illustrative and not limiting; the method further includes: S401, each time a bus electrical signal is sampled, the bus electrical signal is detected based on a preset neural network model, and the detection result output by the neural network model is obtained.

[0088] As an example, a pre-defined neural network model is used to identify and analyze bus electrical signals to monitor whether an arcing fault has occurred in the photovoltaic system. For instance, the pre-defined neural network could be an AFCI neural network.

[0089] As an example, a trained deep learning-based AFCI neural network model is deployed in the inverter controller. After each sampling of the bus electrical signal, the bus electrical signal is input into the AFCI neural network model. The bus electrical signal is detected based on the AFCI neural network model to obtain the detection result. The detection result reflects whether the photovoltaic system has experienced an arc fault or not.

[0090] As an example, the AFCI neural network model is trained using the bus electrical signal as input and the arc confidence score as output. Each time the bus electrical signal is sampled, it is input into the AFCI neural network model. The model performs feature extraction and fusion processing on the bus electrical signal to obtain the arc confidence score corresponding to each sample. The arc confidence score reflects the probability of a fault arc in the bus electrical signal; if the arc confidence score is greater than a preset arc threshold, the detection result is determined to be an arc fault; if the arc confidence score is less than or equal to the preset arc threshold, the detection result is determined to be no arc fault.

[0091] As an example, the bus electrical signal includes the total bus current. The DC bus current is acquired at a sampling rate of 250 kHz and analyzed in real time with 1024 sampling points per frame.

[0092] S402, determine whether the detection result indicates an arc fault.

[0093] If the detection result indicates an arc fault, then S403 is executed to increment the fault counter value by 1.

[0094] If the detection result indicates that no arc fault has occurred, then execute S404 to decrement the fault counter value by 1.

[0095] S405: When the count value of the fault counter is greater than or equal to the preset fault count threshold, an arc fault is confirmed to have occurred in the photovoltaic system.

[0096] In some embodiments, if the detection result of the AFCI neural network model is that an arc fault has occurred, then the photovoltaic system is confirmed to have experienced an arc fault.

[0097] However, when an arc fault occurs in a photovoltaic system, it is necessary to locate the arc fault, which is the aforementioned process. Figure 2 and Figure 3The embodiment illustrates a two-stage localization process. However, the aforementioned arc fault location scheme involves optimizing the system by shutting down the optimizer and sampling a large number of optimizer electrical signals at high frequency. These operations affect photovoltaic system power generation and consume significant communication and computing resources. Therefore, caution is needed when entering the arc fault location process to improve the reliability and accuracy of arc fault detection results. Based on this, this embodiment associates an AFCI neural network model with a fault counter. The fault counter statistically analyzes multiple detection results from the AFCI neural network model, and the system's actual fault is determined based on these multiple detection results.

[0098] For example, when the AFCI neural network model outputs a detection result indicating an arc fault, the fault counter is incremented by 1; when the detection result indicates no arc fault has occurred, the fault counter is decremented by 1. When the cumulative count exceeds a preset fault count threshold (e.g., 20 times), an arc fault is confirmed to have actually occurred in the photovoltaic system, demonstrating high accuracy in arc fault detection.

[0099] In this embodiment, during the initial detection of an arc fault, the bus electrical signal is detected based on a preset neural network model, and the presence of an arc fault in the photovoltaic system is determined based on the count value of the fault counter. If an arc fault is confirmed, the fault counter is cleared, and arc fault localization begins, as in steps S202-S204 of the aforementioned embodiment, to determine the specific location of the arc fault. During the arc fault localization process, while controlling the optimizer in the first string to shut down, the arc fault detection method in this embodiment is used to monitor whether the arc fault in the photovoltaic system is eliminated after shutting down the first string, thereby identifying the fault string. That is, through the preset neural network model, arc fault detection of the photovoltaic system can be achieved simultaneously with the control of the optimizer shutdown operation, quickly eliminating fault strings and thus quickly locating the specific arc fault location.

[0100] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0101] Corresponding to the arc fault location method in the above embodiment, Figure 5 A structural block diagram of the arc fault location device provided in the embodiments of this application is shown. For ease of explanation, only the parts related to the embodiments of this application are shown.

[0102] Reference Figure 5An arc fault location device 50 is used for fault detection in a photovoltaic system. The photovoltaic system includes an inverter circuit and at least two photovoltaic strings. Each photovoltaic string includes multiple photovoltaic modules and multiple optimizers. The output terminal of each photovoltaic module is connected to the input terminal of the corresponding optimizer. The output terminals of the optimizers in each photovoltaic string are connected in series and then connected to the inverter circuit through a DC bus. The arc fault location device 50 includes: Monitoring unit 501 is used to monitor the bus electrical signal of the DC bus; The determining unit 502 is used to determine the first group of photovoltaic strings and the second group of photovoltaic strings from the photovoltaic strings to be identified based on a preset grouping rule when an arc fault is determined based on the bus electrical signal; the initial photovoltaic strings to be identified include all photovoltaic strings. Control unit 503 is used to control the optimizer in the first group of strings to turn off; if the arc fault is eliminated, the first group of strings is determined as a new photovoltaic string to be identified; if the arc fault is not eliminated, the second group of strings is determined as a new photovoltaic string to be identified; return to the step of determining the first group of strings and the second group of strings from the photovoltaic strings to be identified based on the preset grouping rules, until the photovoltaic strings to be identified contain only one photovoltaic string, and the last photovoltaic string to be identified is determined as the fault string; The positioning unit 504 is used to monitor the optimizer electrical signals corresponding to all optimizers in the fault string, and determine the location of the arc fault based on the optimizer electrical signals.

[0103] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0104] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the above device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0105] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps described in the various method embodiments above.

[0106] This application provides a computer program product that, when run on a mobile terminal, enables the mobile terminal to implement the steps described in the above-described method embodiments.

[0107] If the integrated units described above are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. A computer-readable medium can include at least: any entity or device capable of carrying computer program code to a photographic device / terminal device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electrical carrier signals or telecommunication signals.

[0108] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0109] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0110] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for locating arc faults, characterized in that, The method is applied to a photovoltaic system, which includes an inverter circuit and at least two photovoltaic strings. Each photovoltaic string includes multiple photovoltaic modules and multiple optimizers. The output terminal of each photovoltaic module is connected to the input terminal of the corresponding optimizer. The output terminals of the optimizers in each photovoltaic string are connected in series and then connected to the inverter circuit via a DC bus. Monitor the bus electrical signal of the DC bus; When an arc fault is determined to have occurred based on the bus electrical signal, a first group of photovoltaic strings and a second group of photovoltaic strings are determined from the photovoltaic strings to be identified based on a preset grouping rule; the initial photovoltaic strings to be identified include all photovoltaic strings. The optimizer in the first group of strings is turned off; if the arc fault is eliminated, the first group of strings is determined as a new photovoltaic string to be identified; if the arc fault is not eliminated, the second group of strings is determined as a new photovoltaic string to be identified; the process returns to the step of determining the first group of strings and the second group of strings from the photovoltaic strings to be identified based on the preset grouping rules, until the photovoltaic strings to be identified contain only one photovoltaic string, and the last photovoltaic string to be identified is determined as the faulty string; Monitor the optimizer electrical signals corresponding to all optimizers in the fault string, and determine the location of the arc fault based on the optimizer electrical signals.

2. The method according to claim 1, characterized in that, The optimizer electrical signal includes the optimizer's output current, and determining the location of the arc fault based on the optimizer electrical signal includes: Calculate the difference in output current between two adjacent optimizers in the fault string to obtain multiple current differences; The optimizer corresponding to the current difference value greater than the preset threshold value is determined as the arc fault location.

3. The method according to claim 2, characterized in that, The step of calculating the difference in output current between two adjacent optimizers in the fault string yields multiple current differences, including: Each time the output current of each optimizer in the fault string is sampled, the difference between the output currents of two adjacent optimizers in the fault string is calculated to obtain multiple current differences. The step of determining the location of the arc fault by the optimizer corresponding to the current difference value greater than the preset threshold value includes: Increment the count value of the position counter corresponding to the optimizer for current differences exceeding the preset threshold by 1; When the count value of any position counter is detected to be greater than or equal to a preset position count threshold, the optimizer corresponding to the position counter whose count value is greater than or equal to the preset position count threshold is determined as the arc fault location.

4. The method according to claim 3, characterized in that, The method further includes: After identifying the faulty cluster, the sampling frequency of the target sampling circuit on the faulty cluster is increased. The target sampling circuit is used to sample the optimizer electrical signal.

5. The method according to claim 1, characterized in that, The method further includes: Each time a bus electrical signal is sampled, the bus electrical signal is detected based on a preset neural network model to obtain the detection result output by the neural network model; When the detection result indicates that an arc fault has occurred, the count value of the fault counter is incremented by 1; when the detection result indicates that no arc fault has occurred, the count value of the fault counter is decremented by 1. When the count value of the fault counter is greater than or equal to a preset fault count threshold, an arc fault is confirmed to have occurred in the photovoltaic system.

6. The method according to claim 1, characterized in that, The step of determining the first group of strings and the second group of strings from the photovoltaic strings to be identified based on preset grouping rules includes: The photovoltaic strings to be identified are sorted according to the size of their string identifiers; The photovoltaic strings to be identified are determined as the first group of strings based on the largest or smallest of the sorted string identifiers, and the remaining photovoltaic strings to be identified are determined as the second group of photovoltaic strings.

7. The method according to any one of claims 1-6, characterized in that, The method further includes: The location of the arc fault is reported as fault information to the target terminal.

8. An arc fault detection device, characterized in that, For fault detection of a photovoltaic system, the photovoltaic system includes an inverter circuit and at least two photovoltaic strings, each photovoltaic string including multiple photovoltaic modules and multiple optimizers, the output terminal of each photovoltaic module being connected to the input terminal of the corresponding optimizer, and the output terminals of the optimizers in each photovoltaic string being connected in series and then connected to the inverter circuit through a DC bus. The device includes: The monitoring unit is used to monitor the bus electrical signal of the DC bus; The determining unit is used to determine the first group of photovoltaic strings and the second group of photovoltaic strings to be identified based on a preset grouping rule when an arc fault is determined to have occurred based on the bus electrical signal; the initial photovoltaic strings to be identified include all photovoltaic strings. The control unit is used to control the optimizer in the first group of strings to turn off; if the arc fault is eliminated, the first group of strings is determined to be a new photovoltaic string to be identified; if the arc fault is not eliminated, the second group of strings is determined to be a new photovoltaic string to be identified; the process returns to the step of determining the first group of strings and the second group of strings from the photovoltaic strings to be identified based on the preset grouping rules, until the photovoltaic strings to be identified contain only one photovoltaic string, and the last photovoltaic string to be identified is determined to be a faulty string; The positioning unit is used to monitor the optimizer electrical signals corresponding to all optimizers in the fault string, and determine the location of the arc fault based on the optimizer electrical signals.

9. A photovoltaic system, characterized in that, The photovoltaic system includes: an inverter circuit and at least two photovoltaic strings. Each photovoltaic string includes multiple photovoltaic modules and multiple optimizers. The output terminal of each photovoltaic module is connected to the input terminal of the corresponding optimizer. The output terminals of the optimizers in each photovoltaic string are connected in series and then connected to the inverter circuit through a DC bus. The photovoltaic system further includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1 to 7.

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