Wiring detection method, system and device for photovoltaic string and storage medium

Abstract

The invention discloses a wiring detection method, system and device for a photovoltaic string and a storage medium. In the scheme, a preset current interference signal is injected into the input positive end of a target converter connected with a target photovoltaic string in a photovoltaic power supply system; current acquisition signals obtained after current acquisition is carried out on the input ends of all converters except the target converter in the photovoltaic power supply system are obtained, and whether a preset current interference signal exists in the current acquisition signals of any converter except the target converter in the photovoltaic power supply system or not is judged; and determining whether wiring abnormity exists in the target photovoltaic string or not. Whether the preset current interference signal flows to the input end of the converter except the target current through the wrong wiring position or not is detected to determine whether the wiring abnormity exists in the target photovoltaic string, so that the photovoltaic power supply system can be protected in time when the wiring abnormity exists in the photovoltaic string in the photovoltaic power supply system.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic power supply, and in particular to a method, system, device, and storage medium for testing the wiring of photovoltaic strings. Background Technology

[0002] In existing photovoltaic (PV) power supply systems, the input terminals of PV strings and converters must be connected accordingly to ensure normal system operation. However, during actual installation or maintenance, it is easy for the output terminals of different PV strings to be incorrectly connected to the corresponding input terminals of the converters. For example, the negative output terminal of PV string A may be connected to the negative input terminal of converter B, and vice versa. This incorrect connection will cause an abnormal series circuit to form between the output side of the PV strings and the input side of the converter. This results in the output voltages of multiple PV strings being superimposed and acting on the core power devices of the converter, such as the switching transistors. When the converter switching transistors are in a partially conducting and partially cut-off state, the superimposed high voltage will be concentrated on the cut-off switching transistors, causing them to break down and burn out. This, in turn, triggers a chain reaction of damage to the converter and PV strings, seriously threatening the operational safety and stability of the PV system.

[0003] Therefore, accurately detecting the wiring status between photovoltaic strings and converters to avoid device damage and system failures caused by incorrect connections has become an urgent technical problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a method, system, device, and storage medium for detecting the wiring of photovoltaic strings. By detecting whether a preset current interference signal flows to the input terminal of the converter other than the target current through the incorrect wiring, it can determine whether there is a wiring abnormality in the target photovoltaic string, thereby protecting the photovoltaic power supply system in a timely manner when there is a wiring abnormality in the photovoltaic string.

[0005] To solve the above-mentioned technical problems, the present invention provides a method for testing the wiring of photovoltaic strings, comprising:

[0006] A preset current interference signal is injected into the positive input terminal of the target inverter connected to the target photovoltaic string; the target photovoltaic string is any photovoltaic string in the photovoltaic power supply system.

[0007] Acquire the current acquisition signal obtained after acquiring the current at the input terminals of each converter in the photovoltaic power supply system except for the target converter;

[0008] The presence of the preset current interference signal in the current acquisition signal of any converter other than the target converter in the photovoltaic power supply system is determined to determine whether there is a wiring abnormality in the target photovoltaic string.

[0009] Preferably, the presence of the preset current interference signal in the current acquisition signal of any converter other than the target converter in the photovoltaic power supply system is determined to identify whether there is a wiring abnormality in the target photovoltaic string, including:

[0010] If the preset current interference signal is present in the current acquisition signal of any converter other than the target converter in the photovoltaic power supply system, then it is determined that there is a wiring abnormality in the target photovoltaic string.

[0011] The photovoltaic string connected to the converter corresponding to the current acquisition signal that has the preset current interference signal is identified as a photovoltaic string with abnormal wiring.

[0012] Preferably, the presence of the preset current interference signal in the current acquisition signal of any converter other than the target converter in the photovoltaic power supply system is determined to identify whether there is a wiring abnormality in the target photovoltaic string, including:

[0013] If the preset current interference signal is not present in the current acquisition signals of all the converters in the photovoltaic power supply system except for the target converter, then it is determined that there is no wiring abnormality in the target photovoltaic string.

[0014] If there are no wiring abnormalities in any of the photovoltaic strings in the photovoltaic power supply system, then the wiring of the photovoltaic power supply system is considered to be normal.

[0015] Preferably, after confirming that the photovoltaic power supply system wiring is normal, the method further includes:

[0016] Drive commands are sent to each converter in the photovoltaic power supply system to control the grid connection of the photovoltaic power supply system.

[0017] Preferably, determining whether the preset current interference signal exists in the current acquisition signal of any converter in the photovoltaic power supply system other than the target converter includes:

[0018] Spectral analysis is performed on the current acquisition signals of each converter in the photovoltaic power supply system other than the target converter to obtain the spectrum diagram of the current acquisition signals of each converter other than the target converter.

[0019] Determine whether there are actual frequency domain characteristics in the spectrum of the current acquisition signal of any converter other than the converter corresponding to the target photovoltaic string, which are the same as the preset frequency domain characteristics of the preset current interference signal.

[0020] Preferably, the determination is made regarding whether there are actual frequency domain characteristics in the spectrum of the current acquisition signal of any converter other than the converter corresponding to the target photovoltaic string that are identical to the preset frequency domain characteristics of the preset current interference signal, including:

[0021] Determine the preset frequency domain characteristics of the preset current interference signal, wherein the preset frequency domain characteristics include a preset frequency and a preset amplitude corresponding to the preset frequency;

[0022] Determine whether the actual amplitude corresponding to the preset frequency in the spectrum diagram of any converter other than the target converter is the preset amplitude.

[0023] Preferably, determining the preset frequency domain characteristics of the preset current interference signal includes:

[0024] Obtain the target current acquisition signal obtained after acquiring the current at the input terminal of the target converter;

[0025] Spectral analysis is performed on the target current acquisition signal to obtain the spectrum of the target current acquisition signal;

[0026] The preset frequency domain characteristics of the preset current interference signal are obtained from the spectrum diagram of the target current acquisition signal.

[0027] To solve the above-mentioned technical problems, the present invention provides a wiring detection system for photovoltaic strings, comprising:

[0028] The signal injection unit is used to inject a preset current interference signal into the positive input terminal of the target inverter connected to the target photovoltaic string; the target photovoltaic string is any photovoltaic string in the photovoltaic power supply system;

[0029] The acquisition unit is used to acquire the current acquisition signal obtained after acquiring the current at the input terminals of each converter in the photovoltaic power supply system except for the target converter;

[0030] The determining unit is used to determine whether the preset current interference signal exists in the current acquisition signal of any converter other than the target converter in the photovoltaic power supply system, so as to determine whether there is a wiring abnormality in the target photovoltaic string.

[0031] To solve the above-mentioned technical problems, the present invention provides a wiring detection device for photovoltaic strings, comprising:

[0032] Memory, used to store computer programs;

[0033] A processor is used to implement the steps of the photovoltaic string wiring detection method as described above when executing a computer program.

[0034] To address the aforementioned technical problems, the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the photovoltaic string wiring detection method described above.

[0035] This application provides a method, system, device, and storage medium for detecting the wiring of a photovoltaic (PV) string. In this scheme, a preset current interference signal is injected into the positive input terminal of the target inverter connected to the target PV string in the PV power supply system. Current acquisition signals are obtained by acquiring the current at the input terminals of all inverters in the PV power supply system other than the target inverter. The presence of the preset current interference signal in the current acquisition signal of any inverter other than the target inverter is judged to determine whether there is a wiring abnormality in the target PV string. This application detects whether the preset current interference signal flows through an incorrect wiring point to the input terminal of an inverter other than the target inverter to determine whether there is a wiring abnormality in the target PV string, thereby enabling timely protection of the PV power supply system when a wiring abnormality is found in the PV string. Attached Figure Description

[0036] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 A schematic flowchart illustrating a photovoltaic string wiring detection method provided in this application;

[0038] Figure 2 A schematic diagram of a photovoltaic string under normal wiring configuration provided in this application;

[0039] Figure 3 A schematic diagram illustrating a photovoltaic string with a wiring abnormality as provided in this application;

[0040] Figure 4 A schematic diagram of the structure of a photovoltaic string wiring detection system provided in this application;

[0041] Figure 5 A schematic diagram of the structure of a photovoltaic string wiring detection device provided in this application;

[0042] Figure 6 This is a schematic diagram of the structure of a computer-readable storage medium provided in this application. Detailed Implementation

[0043] The core of this invention is to provide a method, system, device, and storage medium for detecting the wiring of photovoltaic strings. By detecting whether a preset current interference signal flows through an incorrect wiring point to the input terminal of the converter other than the target current, it can determine whether there is a wiring abnormality in the target photovoltaic string, thereby protecting the photovoltaic power supply system in a timely manner when there is a wiring abnormality in the photovoltaic string.

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Please refer to Figure 1 , Figure 1 The flowchart illustrates a method for testing the wiring of a photovoltaic string provided in this application. The method includes:

[0046] S11: Inject a preset current interference signal into the positive input terminal of the target inverter connected to the target photovoltaic string; the target photovoltaic string is any photovoltaic string in the photovoltaic power supply system;

[0047] In a photovoltaic (PV) power supply system, multiple PV modules are connected in series to form a PV string. The output of the PV string is connected to an inverter. The inverter converts the direct current output from the PV string into alternating current (AC), which is then connected to the grid, directly supplies power to the load, or charges an energy storage device. Therefore, each PV string is connected to a corresponding inverter, and the parameters of the switching transistor module in each inverter are set according to the output performance of its corresponding PV string.

[0048] Because photovoltaic power supply systems typically contain a large number of photovoltaic (PV) strings, incorrect polarity connections may occur when wiring the PV strings to the inverter. Normally, the positive output terminal of the first PV string should be connected to the positive input terminal of the first inverter, and the negative output terminal of the first PV string should be connected to the negative input terminal of the first inverter. Similarly, the positive output terminal of the second PV string should be connected to the positive input terminal of the second inverter, and the negative output terminal of the second PV string should be connected to the negative input terminal of the second inverter. Please refer to [the relevant documentation / reference]. Figure 2 , Figure 2 This is a schematic diagram of a photovoltaic string under normal wiring conditions, as provided in this application. Figure 2The diagram shows the boost circuit section of the converter. Q1 represents the switching transistor module in the boost circuit of the first converter, L1 is the filter inductor connected to the input of the first converter, and C1 is the DC bus capacitor between the boost circuit and the inverter of the first converter. Q2 represents the switching transistor module in the boost circuit of the second converter, L2 is the filter inductor connected to the input of the second converter, and C2 is the DC bus capacitor between the boost circuit and the inverter of the second converter. However, when the wiring is incorrect, the negative output terminal of the first photovoltaic string may be incorrectly connected to the negative input terminal of the second converter, and vice versa. Figure 3 As shown, Figure 3 This is a schematic diagram illustrating a photovoltaic string with an abnormal wiring condition, as provided in this application. The dashed lines in the diagram represent the current flow. It can be seen that the output sides of the first and second photovoltaic strings are connected in series and in series with the input side of the converter. The output voltages of the first and second photovoltaic strings are superimposed and applied to the switching modules in the boost circuits of the first and second converters. However, since the switching modules in the first and second converters may not be turned on simultaneously, if the switching module in the boost circuit of the first converter is turned on while the switching module in the boost circuit of the second converter is turned off, ignoring the impedance in the turned-on switching module, the turned-on switching module can be considered a short circuit. The output voltages of the first and second photovoltaic strings are all applied to the two ends of the unturned switching module, which will cause the unturned switching module to be damaged due to overvoltage. If the abnormal wiring of the photovoltaic string is not detected in time, it will not only damage the converter and prevent it from working properly, but may even cause the photovoltaic string to burn out.

[0049] Therefore, this application detects whether there are any wiring abnormalities in the photovoltaic string before the inverter is connected to the grid, in order to avoid damage to the inverter or the photovoltaic string caused by wiring abnormalities.

[0050] Specifically, considering that the converter includes a boost circuit and an inverter, a bus capacitor is installed on the DC bus between the boost circuit and the inverter to establish the DC bus voltage. Therefore, when the photovoltaic string and the converter are connected but the converter has not yet started, the photovoltaic string charges the bus capacitor of the converter through the positive and negative output terminals of the converter. That is, since there is a voltage difference between the positive output terminal of the photovoltaic string and the end of the bus capacitor connected to the positive input terminal of the converter, the current flows from the positive output terminal of the photovoltaic string to one end of the bus capacitor, and then from the other end of the bus capacitor to the negative output terminal of the photovoltaic string. At the same time, a preset current interference signal is injected into the positive input terminal of the target converter. When the target photovoltaic string and the target converter are normally connected, the preset current interference signal will flow to one end of the bus capacitor along with the current charging the bus capacitor, and then return to the negative input terminal of the target photovoltaic string from the other end of the bus capacitor. There is no preset current interference signal in other target converters.

[0051] However, if there is an incorrect connection between the target photovoltaic string and other converters, the incorrectly connected converter is named an abnormal converter. For example, if the positive output terminal of the target photovoltaic string is connected to the positive input terminal of the target converter, but the negative output terminal of the target photovoltaic string is connected to the negative input terminal of the abnormal converter, the positive input terminal of the abnormal converter is connected to the positive output terminal of the abnormal photovoltaic string, and the negative input terminal of the target converter is connected to the negative output terminal of the abnormal photovoltaic string, then the target photovoltaic string, the target converter, the abnormal converter, and the abnormal photovoltaic string form a series loop. The preset current interference signal not only exists at the input terminal of the target converter but also flows to the input terminal of the abnormal converter. That is, the preset current interference signal also exists in the converters other than the target converter.

[0052] S12: Obtain the current acquisition signal obtained after acquiring the current at the input terminals of each converter in the photovoltaic power supply system, excluding the target converter;

[0053] To determine whether the target photovoltaic string is connected only to the target converter, that is, whether the target photovoltaic string is incorrectly connected to any converter other than the target converter, current is sampled at the input terminals of each converter other than the target converter to determine the current sampling signals of each converter other than the target converter.

[0054] S13: Determine whether there is a preset current interference signal in the current acquisition signal of any converter other than the target converter in the photovoltaic power supply system, so as to determine whether there is a wiring abnormality in the target photovoltaic string.

[0055] The system judges whether there is a preset current interference signal in the current acquisition signal of any converter other than the target converter, in order to determine whether there is a wiring abnormality in the target photovoltaic string. This allows the system to determine whether the target photovoltaic string can output power to the converter normally without damaging the converter.

[0056] It should be noted that the target photovoltaic string can be any photovoltaic string in the photovoltaic power supply system. Therefore, each photovoltaic string can be set as the target photovoltaic string in sequence to determine whether there are any wiring abnormalities in each photovoltaic string.

[0057] The current acquisition module for acquiring current at the input of the converter can be, but is not limited to, a Hall sensor or a sampling resistor. The current acquisition module is connected in series between the input of the converter and the input of the boost circuit. The injection point for the preset current interference signal can be located at the rear end of the current acquisition module, such as between the input of the converter and the current acquisition module; this application does not limit this. More specifically, the injection point for the preset current interference signal can be located between the filter inductor and the current acquisition module.

[0058] When there is an incorrect connection between the positive output terminals of different photovoltaic strings and the positive input terminals of different converters, the method described in this application can also be used for detection. That is, when the positive output terminal of the target photovoltaic string is connected to the positive input terminal of the abnormal converter, and the negative output terminal of the target photovoltaic string is connected to the negative input terminal of the target converter, and the positive output terminal of the abnormal photovoltaic string is connected to the positive input terminal of the target converter, and the negative output terminal of the abnormal photovoltaic string is connected to the negative input terminal of the abnormal converter, in this case, the preset abnormal current signal injected into the input terminal of the target converter will also flow into the abnormal converter. Thus, it is possible to detect whether there is a preset current interference signal in other converters besides the target converter, thereby determining whether there is a wiring abnormality problem in the target converter.

[0059] Regarding the issue of reversed positive and negative output terminals of different photovoltaic strings, for example, if the positive output terminal of the target photovoltaic string is connected to the negative input terminal of the target converter, and vice versa, the current direction on each converter can be detected simultaneously to determine if the connection is reversed. Alternatively, reverse protection diodes can be installed to protect the circuit from reverse connection issues. Figure 2 and Figure 3 As shown, anti-reverse diodes, namely D1 and D2, can be installed between the boost circuit of the converter and the inverter. The current is cut off when the positive and negative terminals are reversed, thereby protecting the circuit.

[0060] The processor performing the above steps in this application may be, but is not limited to, an MCU (Microcontroller Unit). The MCU injects a preset current interference signal into the positive input terminal of the target converter and acquires the current acquisition signals from the input terminals of each converter other than the target converter in order to detect whether there is a wiring abnormality in the target photovoltaic string.

[0061] In summary, this application detects whether a preset current interference signal flows to the input terminal of the converter other than the target current through an incorrect wiring point to determine whether there is a wiring abnormality in the target photovoltaic string. This allows for timely protection of the photovoltaic power supply system when there is a wiring abnormality in the photovoltaic string.

[0062] Based on the above embodiments:

[0063] As a preferred embodiment, the presence of a preset current interference signal in the current acquisition signal of any converter other than the target converter in the photovoltaic power supply system is determined to identify any wiring abnormalities in the target photovoltaic string, including:

[0064] If a preset current interference signal is present in the current acquisition signal of any converter other than the target converter in the photovoltaic power supply system, it is determined that there is a wiring abnormality in the target photovoltaic string.

[0065] Photovoltaic strings connected to the converter corresponding to the current acquisition signal that has a preset current interference signal are identified as photovoltaic strings with abnormal wiring.

[0066] The system judges whether there is a preset current interference signal in the current acquisition signal of each converter other than the target converter. In other words, it determines whether there is a wiring abnormality between the target photovoltaic string and any converter other than the target converter. This allows for a step-by-step check to see if there is a wiring abnormality between the target photovoltaic string and each converter other than the target converter, avoiding omissions and improving the accuracy of wiring abnormality detection.

[0067] Specifically, if a preset current interference signal exists in the current acquisition signal of any converter other than the target converter, it can be determined that there is a wiring abnormality between the target photovoltaic string and the converter corresponding to the current acquisition signal containing the preset current interference signal. The preset current interference signal flows from the abnormal wiring point of the target photovoltaic string to the abnormal converter, and the photovoltaic string corresponding to the abnormal converter is identified as the abnormal photovoltaic string.

[0068] Based on this, an alarm can also be triggered for abnormal wiring of abnormal photovoltaic strings, allowing staff to determine whether there is a wiring problem between the target photovoltaic string and the abnormal photovoltaic string, and to rewire the abnormal connection to eliminate the fault. Furthermore, if there are multiple abnormal photovoltaic strings, an alarm can also be triggered for abnormal connections between these strings; this application does not limit this aspect.

[0069] As a preferred embodiment, the presence of a preset current interference signal in the current acquisition signal of any converter other than the target converter in the photovoltaic power supply system is determined to identify any wiring abnormalities in the target photovoltaic string, including:

[0070] If there is no preset current interference signal in the current acquisition signals of each converter in the photovoltaic power supply system except for the target converter, then it is determined that there is no wiring abnormality in the target photovoltaic string.

[0071] If there are no wiring abnormalities in any of the photovoltaic strings in the photovoltaic power supply system, then the wiring of the photovoltaic power supply system is considered to be normal.

[0072] If the current acquisition signals of all converters other than the target converter do not include the preset current interference signal, it can be determined that the preset current interference signal has not flowed to other converters through the wiring abnormality. In other words, there is no wiring abnormality between the target photovoltaic string and the other converters except the target converter, and it can be determined that the target photovoltaic string can output power to the target converter normally.

[0073] Furthermore, if each photovoltaic string in the photovoltaic power supply system is taken as the target photovoltaic string in turn, and it is confirmed that there is no wiring abnormality in each photovoltaic string, it can be determined that there is no wiring abnormality in the entire photovoltaic power supply system. That is, the wiring of the photovoltaic power supply system is normal, and each photovoltaic string can output power to the corresponding converter normally.

[0074] As a preferred embodiment, after confirming that the photovoltaic power supply system wiring is normal, the following steps are also included:

[0075] Drive commands are sent to each converter in the photovoltaic power supply system to control the grid connection of the photovoltaic power supply system.

[0076] After confirming that there are no wiring abnormalities in each photovoltaic string, drive commands are sent to each converter in the photovoltaic power supply system to start each converter. Each converter first boosts the DC power output from the corresponding photovoltaic string through a boost circuit, and then inverts the DC power through an inverter before connecting it to the grid, so as to put the photovoltaic power supply system into use.

[0077] As a preferred embodiment, determining whether a preset current interference signal exists in the current acquisition signal of any converter other than the target converter in the photovoltaic power supply system includes:

[0078] Spectral analysis was performed on the current acquisition signals of each converter in the photovoltaic power supply system, excluding the target converter, to obtain the spectrum diagram of the current acquisition signals of each converter, excluding the target converter.

[0079] Determine whether there are actual frequency domain characteristics in the spectrum of the current acquisition signal of any converter other than the converter corresponding to the target photovoltaic string, which are the same as the preset frequency domain characteristics of the preset current interference signal.

[0080] To determine whether a preset current interference signal exists in the current acquisition signal, a spectrum analysis is first performed on the current acquisition signal, such as by performing an FFT (Fast Fourier Transform). It should be noted that the FFT is performed separately on the current acquisition signals of different converters to obtain the spectrum diagrams corresponding to each current acquisition signal. The spectrum diagrams include the frequency domain characteristics of the current acquisition signal, such as the amplitude corresponding to different frequencies. When there is no preset current interference signal in the current acquisition signal, because the photovoltaic string outputs DC power, there are no abnormal spikes in the spectrum diagram of the current acquisition signal. However, if any current acquisition signal has actual frequency domain characteristics in its spectrum diagram that are the same as the preset frequency domain characteristics of the preset current interference signal, it can be determined that there is a wiring abnormality in the target photovoltaic string, and the preset current interference signal flows to a converter other than the target converter through the abnormal wiring.

[0081] Based on this, the frequency domain characteristics of the preset current interference signal are determined by using the spectrum diagram, thereby accurately determining whether there is a wiring abnormality in the target photovoltaic string.

[0082] As a preferred embodiment, it is determined whether there are actual frequency domain characteristics in the spectrum of the current acquisition signal of any converter other than the converter corresponding to the target photovoltaic string that are the same as the preset frequency domain characteristics of the preset current interference signal, including:

[0083] Determine the preset frequency domain characteristics of the preset current interference signal, which include the preset frequency and the preset amplitude corresponding to the preset frequency;

[0084] Determine whether the actual amplitude corresponding to the preset frequency in the spectrum diagram of any converter other than the target converter is the preset amplitude.

[0085] Specifically, the preset frequency domain characteristics of the preset current interference signal are first determined. These preset frequency domain characteristics can be the preset frequency and preset amplitude of the preset current interference signal, which are determined when the preset current interference signal is generated. By identifying whether the actual amplitude corresponding to the preset frequency is the preset amplitude from the spectrum diagram of any converter other than the target converter, it is possible to determine whether the preset frequency domain characteristics of the preset current interference signal exist in the current detection signal. For example, if the preset frequency of the preset current interference signal is 50Hz and the preset amplitude is 1A, then the location of 50Hz is first identified from the spectrum diagram of any converter other than the target converter. Then, it is determined whether the actual amplitude corresponding to 50Hz is 1A. If the actual amplitude corresponding to 50Hz is not 1A, it can be determined that there is a wiring abnormality between the converter corresponding to the current acquisition signal and the target photovoltaic string.

[0086] Based on this, the spectrum diagram can effectively characterize the frequency domain features of the current acquisition signal, thereby determining whether there is a preset current interference signal in the current acquisition signal of any converter other than the target converter, and thus accurately determining whether there is a wiring abnormality in the target photovoltaic string.

[0087] It should be noted that for different target photovoltaic strings, the preset frequency domain characteristics of their corresponding preset current interference signals may be the same or different, and can be distinguished from the frequency domain characteristics of the output current of the target photovoltaic string. This application does not limit this.

[0088] As a preferred embodiment, determining the preset frequency domain characteristics of the preset current interference signal includes:

[0089] Obtain the target current acquisition signal after current acquisition at the input terminal of the target converter;

[0090] Perform spectral analysis on the target current acquisition signal to obtain the spectrum of the target current acquisition signal;

[0091] Obtain the preset frequency domain characteristics of the preset current interference signal from the spectrum diagram of the target current acquisition signal.

[0092] When determining the preset frequency domain characteristics of the preset current interference signal, the preset frequency domain characteristics can be determined not only when the preset current interference signal is generated, but also by sampling the current at the input end of the target converter to determine the target current sampling signal. The preset frequency domain characteristics of the preset current interference signal can be obtained from the spectrum of the target current sampling signal. For example, if there is a peak at 50Hz in the spectrum of the target current sampling signal, then 50Hz can be determined as the preset frequency, and the amplitude corresponding to 50Hz can be determined as the preset amplitude.

[0093] It should be noted that more than one preset frequency domain feature may be determined in the spectrum diagram of the target current acquisition signal. If multiple preset frequency domain features are determined, it can be determined whether the current acquisition signal spectrum diagrams of each converter other than the target converter have the above-mentioned multiple preset frequency domain features, so as to determine whether there is a wiring abnormality problem in the target photovoltaic string.

[0094] Of course, you can also directly use the spectrum of the target current acquisition signal and the spectrum of the current acquisition signals of each converter other than the target converter. Figure 1 A comparison is performed to determine if there is a spectrum matching the target current acquisition signal. Figure 1 The application does not limit the scope of this application to determining whether there are any wiring abnormalities in the target photovoltaic string by analyzing the spectrum diagram.

[0095] Please refer to Figure 4 , Figure 4 This is a schematic diagram of a photovoltaic string wiring detection system provided in this application. The system includes:

[0096] The signal injection unit 41 is used to inject a preset current interference signal into the positive input terminal of the target inverter connected to the target photovoltaic string; the target photovoltaic string is any photovoltaic string in the photovoltaic power supply system;

[0097] The acquisition unit 42 is used to acquire the current acquisition signal obtained after acquiring the current at the input terminals of each converter in the photovoltaic power supply system except for the target converter.

[0098] The determination unit 43 is used to determine whether there is a preset current interference signal in the current acquisition signal of any converter other than the target converter in the photovoltaic power supply system, so as to determine whether there is a wiring abnormality in the target photovoltaic string.

[0099] For a description of the photovoltaic string wiring detection system provided by the present invention, please refer to the above method embodiments; the present invention will not be described again here.

[0100] Please refer to Figure 5 , Figure 5 This is a schematic diagram of the structure of a photovoltaic string wiring detection device provided in this application. The device includes:

[0101] Memory 51 is used to store computer programs;

[0102] The processor 52 is used to implement the steps of the photovoltaic string wiring detection method described above when executing a computer program.

[0103] For a description of the photovoltaic string wiring detection device provided by the present invention, please refer to the above method embodiments; the present invention will not be described again here.

[0104] Please refer to Figure 6 , Figure 6 This is a schematic diagram of the structure of a computer-readable storage medium provided in this application. The computer-readable storage medium 61 stores a computer program 62. When the computer program 62 is executed by the processor 52, it implements the steps of the photovoltaic string wiring detection method described above.

[0105] For a description of the computer-readable storage medium provided by the present invention, please refer to the above method embodiments; the present invention will not be described again here.

[0106] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0107] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of detecting wiring of a photovoltaic string, characterized by, The method comprises the following steps: injecting a preset current interference signal into the input positive terminal of a target converter connected to a target photovoltaic string; the target photovoltaic string is any photovoltaic string in a photovoltaic power supply system; obtaining current collection signals obtained after collecting currents at the input terminals of each converter in the photovoltaic power supply system except the target converter; judging whether the preset current interference signal exists in the current collection signal of any one of the converters in the photovoltaic power supply system except the target converter to determine whether the target photovoltaic string has a wiring abnormality.

2. The method of claim 1, wherein the method further comprises: The method of judging whether the preset current interference signal exists in the current collection signal of any one of the converters in the photovoltaic power supply system except the target converter to determine whether the target photovoltaic string has a wiring abnormality comprises: if the preset current interference signal exists in the current collection signal of any one of the converters in the photovoltaic power supply system except the target converter, it is determined that the target photovoltaic string has a wiring abnormality; the photovoltaic string connected to the converter corresponding to the current collection signal having the preset current interference signal is determined as the photovoltaic string with a wiring abnormality.

3. The method of claim 1, wherein the method further comprises: The method of judging whether the preset current interference signal exists in the current collection signal of any one of the converters in the photovoltaic power supply system except the target converter to determine whether the target photovoltaic string has a wiring abnormality comprises: if the preset current interference signal does not exist in the current collection signal of each of the converters in the photovoltaic power supply system except the target converter, it is determined that the target photovoltaic string does not have a wiring abnormality; if each photovoltaic string in the photovoltaic power supply system does not have a wiring abnormality, it is determined that the photovoltaic power supply system has a normal wiring.

4. The method of claim 3, wherein the method further comprises: After it is determined that the photovoltaic power supply system has a normal wiring, the method further comprises the following steps: sending a driving instruction to each converter in the photovoltaic power supply system to control the photovoltaic power supply system to be connected to a power grid.

5. The method of stringing of a photovoltaic string according to any of claims 1 to 4, characterized in that, The method of judging whether the preset current interference signal exists in the current collection signal of any one of the converters in the photovoltaic power supply system except the target converter comprises the following steps: performing frequency spectrum analysis on the current collection signal of each of the converters in the photovoltaic power supply system except the target converter to obtain a frequency spectrum graph of the current collection signal of each of the converters except the target converter; judging whether an actual frequency domain feature identical to a preset frequency domain feature of the preset current interference signal exists in the frequency spectrum graph of the current collection signal of any one of the converters except the converter corresponding to the target photovoltaic string.

6. The method of claim 5, wherein the method further comprises: The method of judging whether an actual frequency domain feature identical to a preset frequency domain feature of the preset current interference signal exists in the frequency spectrum graph of the current collection signal of any one of the converters except the converter corresponding to the target photovoltaic string comprises the following steps: determining the preset frequency domain feature of the preset current interference signal, wherein the preset frequency domain feature comprises a preset frequency and a preset amplitude corresponding to the preset frequency; determining whether an actual amplitude corresponding to the preset frequency in a frequency spectrum of any one of the converters except the target converter is the preset amplitude.

7. The method of claim 6, wherein the method further comprises: determining a preset frequency domain feature of the preset current interference signal, including: obtaining a target current collection signal obtained after current collection on an input end of the target converter; performing frequency spectrum analysis on the target current collection signal to obtain a frequency spectrum of the target current collection signal; obtaining the preset frequency domain feature of the preset current interference signal from the frequency spectrum of the target current collection signal.

8. A wiring detection system for a photovoltaic string, characterized by, including: a signal injection unit configured to inject a preset current interference signal to a positive input end of a target converter connected to a target photovoltaic string; the target photovoltaic string being any one of photovoltaic strings in a photovoltaic power supply system; an obtaining unit configured to obtain current collection signals obtained after current collection on input ends of each converter in the photovoltaic power supply system except the target converter; a determining unit configured to determine whether the preset current interference signal exists in the current collection signal of any one of the converters except the target converter in the photovoltaic power supply system, to determine whether the target photovoltaic string has a wiring abnormality.

9. A junction detection device for a photovoltaic string, characterized by including: a memory configured to store a computer program; a processor configured to, when executing the computer program, implement steps of the wiring detection method of the photovoltaic string according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer readable storage medium has stored thereon a computer program, and the computer program, when executed by a processor, implements steps of the wiring detection method of the photovoltaic string according to any one of claims 1-7.

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