Diode detection method and system and main control module

Abstract

The invention relates to a diode detection method and system and a main control module. The diode detection method comprises the steps of providing a first electric signal for the photovoltaic module; collecting a first voltage between the positive electrode and the negative electrode of the photovoltaic module, and collecting a first output current of the photovoltaic module; stopping providing the first electric signal and providing a second electric signal at a preset time interval; electrical parameters of the second electric signal and the first electric signal are different; collecting voltage and second output current at two ends of a diode in each junction box; and obtaining a diode detection result according to the electrical parameter of the first electric signal, the electrical parameter of the second electric signal, the first voltage, the first output current, the second output current, the voltage at the two ends of the diode in each junction box, the performance parameter of the photovoltaic module and the performance parameter of the diode in each junction box. Wherein the diode detection results comprise no abnormity, short circuit and open circuit of the diode, and accurate and rapid detection of the diode is realized.

Description

Technical Field

[0001] The present application relates to the technical field of photovoltaic module junction box diode detection, and in particular to a diode detection method, system and main control module. Background Art

[0002] In recent years, the global photovoltaic market has been booming, and the installed capacity has increased year by year. Among them, photovoltaic modules are the main products of photovoltaic power generation. When the power station is operating normally, when foreign objects block the module cells, the hot spot effect will occur. In order to avoid the loss of power generation efficiency and the safety risk of the photovoltaic modules when the hot spot effect occurs, one or more bypass diodes are usually set in the photovoltaic module junction box.

[0003] At present, the detection of whether the diode function is normal in this field mainly relies on the EL test (ElectroLuminescence) before leaving the factory. The photovoltaic module is forward-currented. Using the principle of electroluminescence, the battery cell emits light under the action of the current. The camera captures the light-emitting effect of the battery cell and makes a judgment. If a black string appears in the EL of the photovoltaic module, the corresponding diode has a breakdown short-circuit abnormality. The current mainstream components are all designed with 6 strings of batteries. Due to camera limitations, the EL test is usually composed of three photos, each time taking two strings of batteries. Therefore, the power supply needs to be powered on three times. During the EL test, when the second and third power-on photos are taken, if the diode corresponding to the battery string photographed in the previous test is short-circuited, the black string will not appear in the EL result image, so there is a risk of missed detection. Summary of the invention

[0004] Based on this, it is necessary to provide a diode detection method, system and main control module to address the above technical problems.

[0005] In a first aspect, the present application provides a diode detection method, wherein the diode includes a diode in a plurality of junction boxes connected to a photovoltaic module; the diode detection method includes:

[0006] Providing a first electrical signal to the photovoltaic component;

[0007] Collecting a first voltage between the positive electrode and the negative electrode of the photovoltaic component, and collecting a first output current of the photovoltaic component;

[0008] Stop providing the first electrical signal and provide a second electrical signal after a preset time interval; the electrical parameters of the second electrical signal are different from those of the first electrical signal;

[0009] Collecting the voltage across the diode in each of the junction boxes and the second output current;

[0010] The diode detection result is obtained according to the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the second output current, the voltage across the diode in each of the junction boxes, the first performance parameters of the photovoltaic component and the second performance parameters of the diode in each of the junction boxes.

[0011] In one embodiment, obtaining a diode detection result according to the electrical parameter of the first electrical signal, the electrical parameter of the second electrical signal, the first voltage, the first output current, the second output current, the voltage across the diode in each of the junction boxes, the first performance parameter of the photovoltaic module, and the second performance parameter of the diode in each of the junction boxes includes:

[0012] determining a fault type of the faulty diode according to at least four of the electrical parameter of the first electrical signal, the electrical parameter of the second electrical signal, the first voltage, the first output current, the second output current, the first performance parameter, and the second performance parameter;

[0013] The position of the faulty diode is determined according to the electrical parameter of the second electrical signal and the voltage across the diode in each of the junction boxes.

[0014] In one embodiment, the electrical parameter of the first electrical signal includes a supply voltage; the first performance parameter includes a reverse leakage current of a photovoltaic module; and determining the fault type of the faulty diode according to the electrical parameter of the first electrical signal, the first voltage, the first output current and the first performance parameter includes:

[0015] When the difference between the first voltage and the supply voltage is within a first preset voltage range, and the difference between the first output current and the reverse leakage current is within a first preset current range, it is determined that the fault type of the faulty diode is open circuit.

[0016] In one embodiment, the electrical parameter of the second electrical signal includes a constant voltage; the first performance parameter also includes a forward internal resistance of a photovoltaic module; and determining the fault type of the faulty diode according to the electrical parameter of the first electrical signal, the electrical parameter of the second electrical signal, the first voltage, the first output current, the second output current and the first performance parameter comprises:

[0017] When the difference between the first voltage and the supply voltage is within a first preset voltage range, the difference between the first output current and the reverse leakage current is within a first preset current range, the sum of the voltages across the diodes in each of the junction boxes and the constant voltage meets a preset condition, and the difference between the detection voltage and the constant voltage is within a second preset voltage range, it is determined that the fault type of the faulty diode is an open circuit; the preset condition is related to the number of junction boxes and the number of faulty diodes; the detection voltage is the product of the second output current and the forward internal resistance.

[0018] In one embodiment, the number of junction boxes is M, the number of faulty diodes is N, and the preset condition is that the ratio of the sum of the voltages across the diodes in each of the junction boxes to the constant voltage is (MN):M; M is greater than or equal to N, and both M and N are positive integers.

[0019] In one embodiment, the electrical parameter of the first electrical signal includes a constant current; the second performance parameter includes a forward voltage drop; and determining the fault type of the faulty diode according to the electrical parameter of the first electrical signal, the first voltage, the first output current, and the second performance parameter includes:

[0020] When the difference between the first voltage and the sum of the forward voltage drops of the diodes in the junction boxes is within a third preset voltage range, and the difference between the first output current and the constant current is within a second preset current range, the fault type of the faulty diode is determined to be a short circuit.

[0021] In one embodiment, the electrical parameter of the second electrical signal includes a constant voltage; the first performance parameter also includes a forward internal resistance of a photovoltaic module; and determining the fault type of the faulty diode according to the electrical parameter of the first electrical signal, the electrical parameter of the second electrical signal, the first voltage, the first output current, the second output current and the first performance parameter comprises:

[0022] When the difference between the first voltage and the sum of the forward voltage drops of the diodes in each of the junction boxes is within a third preset voltage range, the difference between the first output current and the constant current is within a second preset current range, the difference between the sum of the voltages across the diodes in each of the junction boxes and the constant voltage is within a fourth preset voltage range, and the difference between the detection voltage and the constant voltage is within the second preset voltage range, it is determined that the fault type of the faulty diode is a short circuit; the detection voltage is the product of the second output current and the forward internal resistance.

[0023] In one embodiment, the voltages across the diodes in each of the junction boxes include a second voltage across the diode in the positive junction box, a third voltage across the diode in the middle junction box, and a fourth voltage across the diode in the negative junction box; determining the position of the faulty diode according to the electrical parameter of the second electrical signal and the voltages across the diodes in each of the junction boxes includes:

[0024] When the difference between the target voltage and 0 is within a fifth preset voltage range, it is determined that the faulty diode is located in a junction box corresponding to the target voltage; the target voltage is any one of the second voltage, the third voltage and the fourth voltage.

[0025] In one embodiment, the electrical parameter of the first electrical signal includes a constant current; the electrical parameter of the second electrical signal includes a constant voltage; the first performance parameter includes a forward internal resistance; the second performance parameter includes a forward voltage drop;

[0026] When the difference between the first voltage and the sum of the forward voltage drops of the diodes in each of the junction boxes is within a third preset voltage range, the difference between the first output current and the constant current is within a second preset current range, the difference between the sum of the voltages across the diodes in each junction box and the constant voltage is within a fourth preset voltage range, and the difference between the detection voltage and the constant voltage is within the second preset voltage range, it is determined that the diode is not faulty; the detection voltage is the product of the output current and the forward internal resistance.

[0027] In a second aspect, the present application further provides a diode detection system for implementing the above-mentioned diode detection method; the diode detection system comprises:

[0028] A first power supply, used to connect the positive electrode and the negative electrode of the photovoltaic module, and to provide a first electrical signal;

[0029] A second power supply, used to connect the positive electrode and the negative electrode of the photovoltaic module, and used to provide a second electrical signal; the second power supply and the first power supply are used to supply power to the photovoltaic module in a time-sharing manner, and the power supply modes are different;

[0030] A voltage detection module, connected to both ends of the diode in each of the junction boxes and the positive and negative electrodes of the photovoltaic module, for respectively detecting the voltage at both ends of the diode in each of the junction boxes and the voltage between the positive and negative electrodes of the photovoltaic module;

[0031] A current detection module, the current detection module is respectively connected to the negative electrode of the photovoltaic component and the voltage detection module, the second power supply and one end of the first power supply connected to the negative electrode of the photovoltaic component, and is used to detect the output current of the photovoltaic component;

[0032] The main control module is connected to the voltage detection module and the current detection module, respectively, and is used to obtain the diode detection result according to the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the second output current, the voltage across the diode in each of the junction boxes, the performance parameters of the photovoltaic module and the performance parameters of the diode in each of the junction boxes.

[0033] In a third aspect, the present application also provides a diode detection device, comprising the diode detection system as described above, a photovoltaic module and a plurality of junction boxes.

[0034] In a fourth aspect, the present application further provides a main control module, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the above-mentioned diode detection method when executing the computer program.

[0035] The above-mentioned diode detection method, system and main control module, the diode includes diodes in multiple junction boxes connected to the photovoltaic component; the diode detection method includes: providing a first electrical signal to the photovoltaic component; collecting a first voltage between the positive and negative poles of the photovoltaic component, and collecting a first output current of the photovoltaic component; stopping providing the first electrical signal and providing a second electrical signal at a preset interval; the electrical parameters of the second electrical signal are different from those of the first electrical signal; collecting the voltage across the diode in each junction box and the second output current; obtaining a diode detection result based on the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the second output current, the voltage across the diode in each junction box, the performance parameters of the photovoltaic component and the performance parameters of the diode in each junction box, wherein the diode detection result includes that the diode has no abnormality, short circuit and open circuit, thereby realizing accurate and rapid detection of the diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A schematic diagram of the connection relationship between a diode and a photovoltaic module in a diode detection method in an embodiment of the present application;

[0038] Figure 2 This is one of the flowcharts of the diode detection method in one embodiment of the present application;

[0039] Figure 3A schematic diagram of a flow chart of obtaining a diode detection result according to an electrical parameter of a first electrical signal, an electrical parameter of a second electrical signal, a first voltage, a first output current, a second output current, a voltage across a diode in each junction box, a first performance parameter of a photovoltaic module, and a second performance parameter of a diode in each junction box in an embodiment of the present application;

[0040] Figure 4 FIG2 is a second flow chart of a diode detection method in an embodiment of the present application;

[0041] Figure 5 Schematic diagram of the structure of a diode detection system in one embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0043] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0045] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0046] See attached Figure 1 , attached Figure 1 The schematic diagram of the connection between the diode (D1~D3) detected by the diode detection method in the present application and the photovoltaic module 210 is shown. In this embodiment, a schematic diagram of the connection between three junction boxes (positive junction box 221, middle junction box 222 and negative junction box 223) and the photovoltaic module 210 is shown. A diode is provided in each of the three junction boxes (positive junction box 221, middle junction box 222 and negative junction box 223). Specifically, the positive junction box 221 is provided with a diode D1, the middle junction box 222 is provided with a diode D2, and the negative junction box 223 is provided with a diode D3.

[0047] In one embodiment, see the attached Figure 2 , attached Figure 2 A schematic flow chart of a diode detection method in an embodiment of the present application is shown; the diode detection method in this embodiment includes the following steps S201 to S205.

[0048] Step S201: providing a first electrical signal to a photovoltaic module.

[0049] Specifically, the first electrical signal may be provided to the photovoltaic assembly by connecting the positive electrode and the negative electrode of the photovoltaic assembly through the power supply source.

[0050] Step S202 , collecting a first voltage between the positive electrode and the negative electrode of the photovoltaic component, and collecting a first output current of the photovoltaic component.

[0051] The first voltage between the positive and negative electrodes of the photovoltaic module can be collected by a voltage collection module or a voltage collection circuit. Similarly, the first output current of the photovoltaic module can be collected by any current collection module or current collection circuit. By comparing the collected first voltage and first output current with the electrical parameters of the first electrical signal, it can be preliminarily detected whether the diode in the junction box connected to the photovoltaic module is faulty. For example, if the first voltage is almost equal to the voltage of the first electrical signal, and the first output current is almost equal to zero, it can be said that at least one diode in the junction box connected to the photovoltaic module is open circuited.

[0052] Step S203, stop providing the first electrical signal and provide a second electrical signal after a preset time interval; the electrical parameters of the second electrical signal are different from those of the first electrical signal.

[0053] At the moment of stopping providing the first electrical signal, the circuit may oscillate for a short time. In order to prevent the oscillation from affecting the power-on test of the diode under the action of the second electrical signal, providing the second electrical signal after a preset interval from stopping providing the first electrical signal is beneficial to improving the test accuracy. For example, the preset interval time can be 5ms~10ms, such as 5ms, 6ms, 7ms, 8ms, 9ms, 10ms, etc., but is not limited thereto.

[0054] The electrical parameters of the second electrical signal and the first electrical signal are different. For example, the first electrical signal may be a constant current signal, and the second electrical signal may be a constant voltage signal, but the present invention is not limited thereto.

[0055] Step S204, collecting the voltage across the diode in each junction box and the second output current.

[0056] Different from the first output current, the second output current is the output current of the photovoltaic component collected under the power supply of the second electrical signal.

[0057] Step S205, obtaining diode detection results according to the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the second output current, the voltage across the diodes in each junction box, the first performance parameters of the photovoltaic module, and the second performance parameters of the diodes in each junction box.

[0058] Among them, the electrical parameters of the first electrical signal and the electrical parameters of the second electrical signal correspond to the power supply modes of the power supply sources of the first electrical signal and the second electrical signal. Exemplarily, if the power supply source of the first electrical signal is a constant current source, the electrical parameters of the first electrical signal may include a power supply voltage and a constant current; if the power supply source of the second electrical signal is a constant voltage source, the electrical parameters of the second electrical signal may include a power supply current and a constant voltage, but are not limited thereto.

[0059] The first performance parameter of the photovoltaic module can be the short-circuit current, forward internal resistance, reverse leakage current and other parameters related to the performance of the photovoltaic module. The second performance parameter of the diode in each junction box can be the forward voltage drop, reverse withstand voltage, reverse leakage current and other parameters related to the performance of the diode.

[0060] The diode detection results include no abnormality, open circuit and short circuit. For example, if the first voltage is almost equal to the voltage of the first electrical signal, and the first output current is almost equal to zero, it can be said that at least one diode in the junction box connected to the photovoltaic module has an open circuit; in order to further determine the position of the open circuit diode, it can be judged by the voltage across the diode in each junction box. For example, if the voltage of the second electrical signal is 30V, the voltage across the diode in the positive junction box is close to 10V, the voltage across the diode in the middle junction box is close to 0V, and the voltage across the diode in the negative junction box is close to 10V, it means that the diode in the middle junction box has an open circuit, and the diodes in the positive junction box and the diodes in the negative junction box are normal.

[0061] In this embodiment, the diode detection result is obtained based on the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the second output current, the voltage across the diode in each junction box, the performance parameters of the photovoltaic module, and the performance parameters of the diode in each junction box, wherein the diode detection result includes whether the diode has no abnormality, short circuit, and open circuit, thereby achieving accurate and rapid detection of the diode.

[0062] In one embodiment, see the attached Figure 3 , attached Figure 3 A schematic diagram of a process for obtaining diode detection results based on the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the second output current, the voltage across the diode in each junction box, the first performance parameter of the photovoltaic module, and the second performance parameter of the diode in each junction box is shown. In this embodiment, the process of obtaining the diode detection results based on the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the second output current, the voltage across the diode in each junction box, the first performance parameter of the photovoltaic module, and the second performance parameter of the diode in each junction box includes the following steps S301 to S302.

[0063] Step S301, determining the fault type of the faulty diode according to at least four of the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the second output current, the first performance parameter, and the second performance parameter.

[0064] Exemplarily, whether the diodes in each junction box are normal can be determined based on the electrical parameters of the first electrical signal, the first voltage, the first output current and the second performance parameter; for example, when the constant current of the first electrical signal is 3A, the forward voltage drops (i.e., the second performance parameter) of the diodes in the three junction boxes (only one diode is provided in one junction box) are all 0.4V, if the first voltage is 1.2V±0.3V and the first output current is 3A±0.3A, it means that the diodes in the three junction boxes are normal.

[0065] According to the electrical parameters of the first electrical signal, the first performance parameter, the first voltage and the first output current, it can be determined whether the faulty diode is open-circuited; for example, if the reverse leakage current (i.e., the first performance parameter) of the photovoltaic module is 50uA, and the supply voltage of the first electrical signal is 45V, if the first voltage is 45V±0.3V and the first current is 50uA±5uA, it means that the diode in at least one junction box has an open-circuit fault.

[0066] Whether the faulty diode is short-circuited can be determined based on the first voltage, the first output current and the second performance parameter. For example, if the constant current of the first electrical signal is 18A and the forward voltage drops (i.e., the second performance parameter) of the three diodes (only one diode is provided in a junction box) are all 0.4V, if the first voltage is 0.8V±80mV and the first output current is 18A±1A, it means that one diode is short-circuited.

[0067] Step S302 : determining the position of the faulty diode according to at least two of the electrical parameter of the second electrical signal, the second output current, and the voltage across the diode in each junction box.

[0068] Exemplarily, taking the case where the electrical parameters of the second electrical signal include a constant voltage, and multiple junction boxes are respectively a positive junction box, an intermediate junction box, and a negative junction box, if the constant voltage of the second electrical signal is 45V, if the voltage across the diode in the positive junction box is 15V±1.5V, the voltage across the diode in the intermediate junction box is 0±1.5V, and the voltage across the diode in the negative junction box is 15V±1.5V, then it means that there is a short circuit in the intermediate junction box.

[0069] As another example, taking the example that the electrical parameters of the second electrical signal include a constant voltage, and multiple junction boxes are respectively a positive junction box, an intermediate junction box, and a negative junction box, if the constant voltage of the second electrical signal is 45V, if the voltage across the diode in the positive junction box is 22.5±1.5V, the voltage across the diode in the intermediate junction box is 0±1.5V, and the voltage across the diode in the negative junction box is 22.5V±1.5V, then it means that there is a short circuit in the intermediate junction box.

[0070] In this embodiment, the fault type of the faulty diode is determined based on at least four of the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the first performance parameter, and the second performance parameter, and the position of the faulty diode is determined based on at least two of the electrical parameters of the second electrical signal, the second output current, and the voltage across the diode in each junction box. The fault type and fault position of the diode can be determined quickly and accurately, thereby achieving comprehensive detection of the diodes in the junction boxes of photovoltaic modules.

[0071] In one embodiment, the electrical parameters of the first electrical signal include the supply voltage; the first performance parameter includes the reverse leakage current of the photovoltaic component; the fault type of the fault diode is determined according to the electrical parameters of the first electrical signal, the first voltage, the first output current and the first performance parameter, including: when the difference between the first voltage and the supply voltage is within a first preset voltage range, and the difference between the first output current and the reverse leakage current is within a first preset current range, determining that the fault type of the fault diode is an open circuit.

[0072] Among them, the difference between the first voltage and the power supply voltage within the first preset voltage range can be understood as the first voltage and the power supply voltage are almost equal, and the difference can be flexibly set in the first preset voltage range according to the actual detection accuracy, for example, it can be 0%~10% of the power supply voltage. For example, if the power supply voltage is 45V, the first preset voltage range can be 0V~4.5V, and correspondingly, the first voltage can be 40.5V~45V, but not limited to this. Similarly, the difference between the first output current and the reverse leakage current within the first preset current range can also be understood as the first output current and the reverse leakage current are almost equal, and the difference can be flexibly set in the first preset current range according to the requirements for detection accuracy, for example, it can be 0%~10% of the reverse leakage current. If the reverse leakage current is 50uA, the first preset current range can be 0uA~5uA, and correspondingly the first output current can be 45uA~50uA, but not limited to this.

[0073] In this embodiment, according to the difference between the first voltage and the supply voltage and the difference between the first output current and the reverse leakage current, the fault type of the faulty diode can be quickly and accurately determined to be open circuit, thereby realizing detection of the open circuit diode.

[0074] In one embodiment, the electrical parameters of the second electrical signal include a constant voltage; the first performance parameters also include the forward internal resistance of the photovoltaic module; the fault type of the faulty diode is determined according to the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the second output current and the first performance parameters, including: when the difference between the first voltage and the supply voltage is within a first preset voltage range, the difference between the first output current and the reverse leakage current is within a first preset current range, the sum of the voltages across the diodes in each junction box and the constant voltage meets a preset condition and the difference between the detection voltage and the constant voltage is within a second preset voltage range, the fault type of the faulty diode is determined to be an open circuit; the preset condition is related to the number of junction boxes and the number of faulty diodes; the detection voltage is the product of the second output current and the forward internal resistance.

[0075] In this embodiment, the diode open circuit is detected by further combining Ohm's law, the relationship between the sum of the voltages at both ends of the diodes in each junction box and the constant voltage, and the second output current, which can further improve the detection accuracy of the diode. The difference between the detection voltage and the constant voltage can be understood as the detection voltage being nearly equal to the constant voltage within the second preset voltage range, and the specific second preset voltage range can be flexibly set according to the actual requirements for detection accuracy. For example, it can be set to 0%~10% of the constant voltage, but is not limited to this.

[0076] Exemplarily, taking the number of junction boxes as 3, only one diode is arranged in each junction box, the constant voltage of the second electrical signal is 45V, the reverse leakage current is 50uA, the supply voltage of the first electrical signal is 45V, and the forward internal resistance of the photovoltaic component is 22.5Ω, if the first voltage is 45V (taking the first preset voltage range of 0V~4.5V as an example), the first output current is 50uA (taking the first preset current range of 0A~5uA as an example), the sum of the voltages across the diodes in the three junction boxes is 30V, and the second output current is 2A (that is, the detection voltage is 2A×22.5Ω=45V), since 30V / 45V=2 / 3, that is, the number of faulty diodes is 1, then since the sum of the voltages across the diodes in the three junction boxes is much smaller than the constant voltage, and the detection voltage is equal to the constant voltage, the faulty diode also has an open circuit fault.

[0077] In one embodiment, the number of junction boxes is M, the number of faulty diodes is N, and the preset condition is that the ratio of the sum of the voltages across the diodes in each junction box to the constant voltage is (MN):M; M is greater than or equal to N, and both M and N are positive integers.

[0078] Exemplarily, if the number of junction boxes M=3 and the number of faulty diodes N=1, taking the constant voltage of 45V as an example, if the sum of the voltages across the diodes in each junction box is 30V, then the corresponding ratio of the sum of the voltages across the diodes in each junction box to the constant voltage is 2:3, which means that the preset conditions are met, so it can be determined that the fault type of the faulty diode is an open circuit.

[0079] Due to the consumption of voltage and current in components in the hardware circuit, the sum of the voltages across the diodes in each junction box may not be completely equal to 30V. Therefore, in some cases, the ratio of the sum of the voltages across the diodes in each junction box to the constant voltage is approximately 2:3, which can also be considered to meet the preset conditions. For example, the sum of the voltages across the diodes in each junction box is 27V~30V. The specific setting can be flexibly based on the detection accuracy, but is not limited to this.

[0080] In one embodiment, the electrical parameters of the first electrical signal include a constant current; the second performance parameter includes a forward voltage drop; the fault type of the faulty diode is determined based on the electrical parameters of the first electrical signal, the first voltage, the first output current, and the second performance parameter, including: when the difference between the first voltage and the sum of the forward voltage drops of the diodes in each junction box is within a third preset voltage range, and the difference between the first output current and the constant current is within a second preset current range, determining that the fault type of the faulty diode is a short circuit.

[0081] Among them, the difference between the first voltage and the sum of the forward voltage drops of the diodes in each junction box can be understood as the first voltage being almost equal to the sum of the forward voltage drops of the diodes in each junction box in the third preset voltage range. The third preset voltage range can be set to 0%~10% of the sum of the forward voltage drops of the diodes in each junction box, which can be flexibly set according to the requirements for detection accuracy, but is not limited to this. For example, taking the forward voltage drop of the diodes in each junction box as 0.4V, the number of junction boxes as three, and only one diode in each junction box as an example, the third preset voltage range can be 0V~0.12V. Similarly, the difference between the first output current and the constant current in the second preset current range can be understood as the first output current being almost equal to the constant current, for example, the second preset current range can be 0%~10% of the constant current, such as the constant current is 25A, and the corresponding second preset current range can be 0A~2.5A, which can be flexibly set according to the requirements for detection accuracy, but is not limited to this.

[0082] In this embodiment, whether the diode has a short circuit fault can be determined based on the difference between the first voltage and the sum of the forward voltage drops of the diodes in each junction box and the difference between the first output current and the constant current, so that the short circuit fault of the diode can be accurately detected.

[0083] In one embodiment, the electrical parameters of the second electrical signal include a constant voltage; the first performance parameters also include the forward internal resistance of the photovoltaic component; the fault type of the faulty diode is determined according to the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the second output current and the first performance parameters, including: when the difference between the first voltage and the sum of the forward voltage drops of the diodes in each junction box is within a third preset voltage range, the difference between the first output current and the constant current is within a second preset current range, the difference between the sum of the voltages across the diodes in each junction box and the constant voltage is within a fourth preset voltage range, and the difference between the detection voltage and the constant voltage is within the second preset voltage range, the fault type of the faulty diode is determined to be a short circuit; the detection voltage is the product of the second output current and the forward internal resistance.

[0084] In this embodiment, two judgment conditions are added on the basis of the diode short circuit fault in the previous embodiment - the difference between the sum of the voltages at both ends of the diode in each junction box and the constant voltage, and the difference between the detection voltage and the constant voltage, which can further verify whether the diode is short-circuited and improve the accuracy of diode detection.

[0085] The difference between the sum of the voltages across the diodes in each junction box and the constant voltage within the fourth preset voltage range can be understood as the sum of the voltages across the diodes in each junction box being approximately equal to the constant voltage, wherein the fourth preset voltage range can be flexibly set according to the requirements for detection accuracy, for example, it can be 0% to 10% of the constant voltage, such as if the constant voltage is 45V, then the fourth preset voltage range can be 0V to 4.5V, not limited thereto. Similarly, the difference between the detection voltage and the constant voltage within the second preset voltage range can also be understood as the detection voltage being approximately equal to the constant voltage.

[0086] In one embodiment, the voltages across the diodes in each junction box include a second voltage across the diode in the positive junction box, a third voltage across the diode in the middle junction box, and a fourth voltage across the diode in the negative junction box; the position of the faulty diode is determined based on the electrical parameters of the second electrical signal and the voltages across the diodes in each junction box, including: when the difference between the target voltage and 0 is within a fifth preset voltage range, determining that the faulty diode is located in the junction box corresponding to the target voltage; the target voltage is any one of the second voltage, the third voltage, and the fourth voltage.

[0087] Among them, the difference between the target voltage and 0 within the fifth preset voltage range can be understood as the target voltage being close to 0, wherein the fifth preset voltage range can be 0V~50mV, which can be flexibly set according to the actual test accuracy, and is not limited thereto. Exemplarily, when the difference between the second voltage and 0 is within the fifth preset range, it means that the diode of the positive junction box is faulty; when the difference between the third voltage and 0 is within the fifth preset range, it means that the diode of the middle junction box is faulty; when the difference between the fourth voltage and 0 is within the fifth preset range, it means that the diode of the negative junction box is faulty.

[0088] In this embodiment, the position of the faulty diode can be determined based on whether the differences between the second voltage, the third voltage, the fourth voltage and 0 are respectively within the fifth preset voltage range, which is conducive to quickly replacing or repairing the faulty diode.

[0089] In one embodiment, the electrical parameters of the first electrical signal include a constant current; the electrical parameters of the second electrical signal include a constant voltage; the first performance parameter includes a forward internal resistance; the second performance parameter includes a forward voltage drop; when the difference between the first voltage and the sum of the forward voltage drops of the diodes in each junction box is within a third preset voltage range, the difference between the first output current and the constant current is within a second preset current range, the difference between the sum of the voltages across the diodes in each junction box and the constant voltage is within a fourth preset voltage range, and the difference between the detection voltage and the constant voltage is within the second preset voltage range, it is determined that the diode is not faulty; the detection voltage is the product of the output current and the forward internal resistance.

[0090] In this embodiment, the difference between the first voltage and the sum of the forward voltage drops of the diodes in each junction box is within the third preset voltage range, the difference between the first output current and the constant current is within the second preset current range, the difference between the sum of the voltages across the diodes in each junction box and the constant voltage is within the fourth preset voltage range, and the difference between the detection voltage and the constant voltage is within the second preset voltage range, indicating that the working status of each diode is normal and there is no abnormality, thereby further improving the comprehensiveness of diode detection.

[0091] In one embodiment, a diode detection method is also provided. Figure 4 , attached Figure 4 The second structural schematic diagram of the diode detection system in this embodiment is shown, wherein the first power supply can provide a constant current signal of 5V~45V, 3A~25A (that is, the first electrical signal in any of the above embodiments), and the first voltage and the first output current are collected. Taking the photovoltaic component as a 600W double-glass component with a short-circuit current of 18A, a forward resistance of 22.5Ω, and a reverse leakage of less than 50 microamperes; a single diode in each junction box has a forward voltage drop of 0.4V, a reverse withstand voltage of 50V, and a reverse leakage of 20 microamperes as an example, if the first voltage corresponds to 1.2V~2.4V and the first output current corresponds to 3A~25A, within 5ms~10ms when the first power supply stops supplying power, the second power supply provides a second power supply signal of 30V~45V, 2A~10A. At this time, if the second voltage, the third voltage, and the fourth voltage all correspond to 10V~15V, and the second output current is 2A~10A, it means that there is no abnormality in the diodes in each junction box.

[0092] If the first voltage corresponds to 5V~45V, the first output current is 0A, and the second power supply provides a second power supply signal of 30V~45V and 2A~10A within 5ms~10ms after the first power supply stops supplying power, if the second voltage is 10V~15V, the third voltage is 0V, and the fourth voltage is 10V~15V, and the second output current corresponds to 2A~10A, it means that the diode in the middle junction box has a short circuit fault, while the diodes in the positive junction box and the negative junction box are normal.

[0093] If the first voltage corresponds to 0V~1.6V, and the first output current corresponds to 3A~25A, and the first power supply stops supplying power within 5ms~10ms, the second power supply provides a second power supply signal of 30V~45V and 2A~10A. At this time, if the second voltage is 15V~22.5V, the third voltage is 0V, the fourth voltage is 15V~22.5V, and the second output current is 2A~10A, it means that the diode in the middle junction box has a short circuit fault, while the diodes in the positive junction box and the negative junction box are normal.

[0094] Specifically, taking the example that the first power supply provides a 45V power supply voltage and a 18V constant current, and the second power supply provides a 45V constant voltage and a 10A power supply current, the first power supply starts to output a first power supply signal of a 45V power supply voltage and a 18V constant current, collects the first output current and the first voltage, and if the first voltage is 1.2V and the first output current is 18A, then the second power supply is turned on within 5ms of turning off the first power supply to output a second power supply signal of a 45V constant voltage and a 10A power supply current. If the second voltage, the third voltage and the fourth voltage are all 15V, and the second output current is 2A, it means that there is no abnormality in the diodes in each junction box; if the first voltage is 45V and the first output current is 0uA~50uA, then the first power supply is turned off. The second power supply is opened within 5ms to output a second power supply signal with a constant voltage of 45V and a power supply current of 10A. If the second voltage and the fourth voltage are both 15V, the third voltage is 0V and the second output current is 2A, it is determined that the diode in the intermediate junction box has an open circuit fault, and the diodes in the positive junction box and the negative junction box are normal. If the first voltage is 0.8V and the first output current is 18A, then the second power supply is opened within 5ms of closing the first power supply to output a second power supply signal with a constant voltage of 45V and a power supply current of 10A. If the second voltage and the fourth voltage are both 22.5V, the third voltage is 0V and the second output current is 3A, it is determined that the diode in the intermediate junction box has a short circuit fault, and the diodes in the positive junction box and the negative junction box are normal.

[0095] The diode detection method in this embodiment can perform diode detection through a set of diode detection devices alone, which is suitable for the final full inspection of the photovoltaic module workshop production line to ensure that the diodes in the junction boxes of the photovoltaic modules are functioning normally before they leave the factory. It can also be set up in photovoltaic module warehouses to perform secondary confirmation of risky photovoltaic modules. It can also be applied to photovoltaic power station project sites to confirm the diode function of the modules before the photovoltaic modules are installed on the brackets.

[0096] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0097] The embodiment of the present application also provides a diode detection system for implementing the diode detection method involved above. The implementation solution provided by the diode detection system to solve the problem is similar to the implementation solution recorded in the above method, so the specific limitations in one or more diode detection system embodiments provided below can refer to the limitations of the diode detection method above, and will not be repeated here.

[0098] In one embodiment, see the attached Figure 5 , attached Figure 5The result schematic diagram of the diode detection system 100 in the present embodiment is shown. The diode detection system 100 in the present embodiment includes a first power supply 110, a second power supply 120, a voltage detection module 130, a current detection module 140 and a main control module 150. The first power supply 110 is used to connect the positive and negative poles of the photovoltaic component 210 to provide a first electrical signal; the second power supply 120 is used to connect the positive and negative poles of the photovoltaic component 210 to provide a second electrical signal; the second power supply 120 and the first power supply 110 are used to supply power to the photovoltaic component 210 in a time-sharing manner, and the power supply methods are different; the voltage detection module 130 is connected to both ends of the diode in each junction box and the positive and negative poles of the photovoltaic component 210, and is used to respectively detect the voltage at both ends of the diode in each junction box and the voltage between the positive and negative poles of the photovoltaic component 210; the current detection module 140 The main control module 150 is respectively connected to the negative electrode of the photovoltaic component 210 and the voltage detection module 130, the second power supply 120, and one end of the first power supply 110 connected to the negative electrode of the photovoltaic component 210, and is used to detect the output current of the photovoltaic component 210; the main control module 150 is respectively connected to the current detection module 140 and the voltage detection module 130, and is used to obtain the diode detection result according to the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the second output current, the voltage across the diodes in each junction box, the performance parameters of the photovoltaic component, and the performance parameters of the diodes in each junction box.

[0099] The first power supply 110 may be a constant current source, the second power supply 120 may be a constant voltage source, and the electrical parameters of the first power supply signal are power supply voltage and constant current, and the electrical parameters of the second power supply signal are power supply current and constant voltage. The voltage detection module 130 may include a plurality of voltage detection units to respectively collect the first voltage of the photovoltaic assembly 210, the second voltage across the diode D1 in the positive junction box 221, and the third voltage across the diode D22 in the intermediate junction box 222, for example, including a first voltage detection unit, a second voltage detection unit, a third voltage detection unit and a fourth voltage detection unit, the first voltage detection unit is respectively connected to the positive and negative electrodes of the photovoltaic assembly to detect the first voltage, the second voltage detection unit is respectively connected to the anode and cathode of the diode D1 to detect the second voltage, the third voltage detection unit is respectively connected to the anode and cathode of the diode D2 to detect the third voltage, and the fourth voltage detection unit is respectively connected to the anode and cathode of the diode D3 to detect the fourth voltage.

[0100] In addition, the diode detection system 100 in this embodiment may also include a power interface to connect to the positive electrode and the negative electrode of the photovoltaic module through the power interface.

[0101] In other embodiments, the diode detection system 100 may further include an acquisition module, which is respectively connected to the voltage detection module 130, the current detection module 140 and the main control module 150, and is used to collect the first voltage to the fourth voltage detected by the voltage detection module 130 and the first output current and the second output current detected by the current detection module 140 and transmit them to the main control module 150.

[0102] In one embodiment, a diode detection device is further provided. The diode detection device in this embodiment includes the diode detection system, photovoltaic components and multiple junction boxes in the above embodiments.

[0103] In one embodiment, the present application further provides a main control module. The main control module in this embodiment includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, the diode detection method in the above embodiment is implemented.

[0104] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the application. It should be noted that, for a person of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A diode detection method, characterized in that: The diodes include diodes in a plurality of junction boxes connected to photovoltaic modules; and the diode detection method includes: Providing a first electrical signal to the photovoltaic component; Collecting a first voltage between the positive electrode and the negative electrode of the photovoltaic component, and collecting a first output current of the photovoltaic component; Stop providing the first electrical signal and provide a second electrical signal after a preset time interval; the electrical parameters of the second electrical signal are different from those of the first electrical signal; Collecting the voltage across the diode in each of the junction boxes and the second output current; The diode detection result is obtained according to the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the second output current, the voltage across the diode in each of the junction boxes, the first performance parameters of the photovoltaic component and the second performance parameters of the diode in each of the junction boxes.

2. The diode detection method according to claim 1, characterized in that: Obtaining a diode detection result according to the electrical parameter of the first electrical signal, the electrical parameter of the second electrical signal, the first voltage, the first output current, the second output current, the voltage across the diode in each of the junction boxes, the first performance parameter of the photovoltaic module, and the second performance parameter of the diode in each of the junction boxes, including: determining a fault type of the faulty diode according to at least four of the electrical parameter of the first electrical signal, the electrical parameter of the second electrical signal, the first voltage, the first output current, the second output current, the first performance parameter, and the second performance parameter; The position of the faulty diode is determined according to the electrical parameter of the second electrical signal and the voltage across the diode in each of the junction boxes.

3. The diode detection method according to claim 2, characterized in that: The electrical parameter of the first electrical signal includes the supply voltage; the first performance parameter includes the reverse leakage current of the photovoltaic module; Determining a fault type of the faulty diode according to the electrical parameter of the first electrical signal, the first voltage, the first output current, and the first performance parameter includes: When the difference between the first voltage and the supply voltage is within a first preset voltage range, and the difference between the first output current and the reverse leakage current is within a first preset current range, it is determined that the fault type of the faulty diode is open circuit.

4. The diode detection method according to claim 3, characterized in that: The electrical parameter of the second electrical signal includes a constant voltage; the first performance parameter also includes a forward internal resistance of a photovoltaic module; and determining a fault type of a faulty diode according to the electrical parameter of the first electrical signal, the electrical parameter of the second electrical signal, the first voltage, the first output current, the second output current and the first performance parameter includes: When the difference between the first voltage and the supply voltage is within a first preset voltage range, the difference between the first output current and the reverse leakage current is within a first preset current range, the sum of the voltages across the diodes in each of the junction boxes and the constant voltage meets a preset condition, and the difference between the detection voltage and the constant voltage is within a second preset voltage range, it is determined that the fault type of the faulty diode is an open circuit; the preset condition is related to the number of junction boxes and the number of faulty diodes; the detection voltage is the product of the second output current and the forward internal resistance.

5. The diode detection method according to claim 4, characterized in that: The number of junction boxes is M, the number of faulty diodes is N, and the preset condition is that the ratio of the sum of the voltages across the diodes in each junction box to the constant voltage is (MN):M; M is greater than or equal to N, and both M and N are positive integers.

6. The diode detection method according to claim 2, characterized in that: The electrical parameter of the first electrical signal includes a constant current; the second performance parameter includes a forward voltage drop; and determining the fault type of the faulty diode according to the electrical parameter of the first electrical signal, the first voltage, the first output current, and the second performance parameter includes: When the difference between the first voltage and the sum of the forward voltage drops of the diodes in the junction boxes is within a third preset voltage range, and the difference between the first output current and the constant current is within a second preset current range, the fault type of the faulty diode is determined to be a short circuit.

7. The diode detection method according to claim 6, characterized in that: The electrical parameter of the second electrical signal includes a constant voltage; the first performance parameter also includes a forward internal resistance of a photovoltaic module; and determining a fault type of a faulty diode according to the electrical parameter of the first electrical signal, the electrical parameter of the second electrical signal, the first voltage, the first output current, the second output current and the first performance parameter includes: When the difference between the first voltage and the sum of the forward voltage drops of the diodes in each of the junction boxes is within a third preset voltage range, the difference between the first output current and the constant current is within a second preset current range, the difference between the sum of the voltages across the diodes in each of the junction boxes and the constant voltage is within a fourth preset voltage range, and the difference between the detection voltage and the constant voltage is within the second preset voltage range, it is determined that the fault type of the faulty diode is a short circuit; the detection voltage is the product of the second output current and the forward internal resistance.

8. The diode detection method according to claim 2, characterized in that: The voltages across the diodes in each of the junction boxes include a second voltage across the diode in the positive junction box, a third voltage across the diode in the middle junction box, and a fourth voltage across the diode in the negative junction box; Determining the position of the faulty diode according to the electrical parameter of the second electrical signal and the voltage across the diode in each of the junction boxes includes: When the difference between the target voltage and 0 is within a fifth preset voltage range, determining that the faulty diode is located in a junction box corresponding to the target voltage; The target voltage is any one of the second voltage, the third voltage, and the fourth voltage.

9. The diode detection method according to claim 1, characterized in that: The electrical parameter of the first electrical signal includes a constant current; the electrical parameter of the second electrical signal includes a constant voltage; the first performance parameter includes a forward internal resistance; the second performance parameter includes a forward voltage drop; When the difference between the first voltage and the sum of the forward voltage drops of the diodes in each of the junction boxes is within a third preset voltage range, the difference between the first output current and the constant current is within a second preset current range, the difference between the sum of the voltages across the diodes in each junction box and the constant voltage is within a fourth preset voltage range, and the difference between the detection voltage and the constant voltage is within the second preset voltage range, it is determined that the diode is not faulty; the detection voltage is the product of the output current and the forward internal resistance.

10. A diode detection system, characterized in that: Used to implement the diode detection method according to any one of claims 1 to 9; the diode detection system comprises: A first power supply, used to connect the positive electrode and the negative electrode of the photovoltaic module, and to provide a first electrical signal; A second power supply, used to connect the positive and negative electrodes of the photovoltaic module and to provide a second electrical signal; the second power supply and the first power supply are used to supply power to the photovoltaic module in a time-sharing manner, and the power supply modes are different; A voltage detection module, connected to both ends of the diode in each of the junction boxes and the positive and negative electrodes of the photovoltaic module, for respectively detecting the voltage at both ends of the diode in each of the junction boxes and the voltage between the positive and negative electrodes of the photovoltaic module; A current detection module, the current detection module is respectively connected to the negative electrode of the photovoltaic component and the voltage detection module, the second power supply and one end of the first power supply connected to the negative electrode of the photovoltaic component, and is used to detect the output current of the photovoltaic component; The main control module is connected to the voltage detection module and the current detection module, respectively, and is used to obtain the diode detection result according to the electrical parameters of the first electrical signal, the electrical parameters of the second electrical signal, the first voltage, the first output current, the second output current, the voltage across the diode in each of the junction boxes, the performance parameters of the photovoltaic module and the performance parameters of the diode in each of the junction boxes.

11. A main control module, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the diode detection method according to any one of claims 1 to 9 is implemented.

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