Iv curve scanning method and related device

Abstract

The present disclosure provides an IV curve scanning method and a related device. In the present disclosure, during scanning, a power converter corresponding to a module to be scanned is directly used to perform an IV curve scanning operation on said module to obtain an IV curve scanning result of said module, compared with an IV curve of the entire string, the IV curve scanning result of each module can more visually display the specific voltage and current scanning conditions of each module, and the obtained IV curve of the module is highly accurate and meets actual data requirements. In addition, in the present disclosure, before IV curve scanning, the string current of a target photovoltaic string is increased, so that the current scanning range during scanning is larger, and the scanning result better conforms to the actual current situation of the module. Furthermore, in the present disclosure, during scanning, the string current of the target photovoltaic string is fixed within a preset current range, so that the problem of current fluctuation during scanning caused by an external environment can be mitigated, the scanning accuracy is improved, and thus fault diagnosis is more accurate.

Description

An IV curve scanning method and related device

[0001] The present disclosure claims priority to the Chinese domestic publication with the application number CN202410817160.9, the title of which is "An IV curve scanning method and related device", filed on June 21, 2024, with the Chinese Patent Office, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] Embodiments of the present disclosure relate to an IV curve scanning method and related device. BACKGROUND

[0003] A photovoltaic system is composed of photovoltaic modules, inverters and other devices. Multiple photovoltaic modules can form a string, and the number of modules in each string is configured according to actual configuration.

[0004] SUMMARY

[0005] Therefore, the present disclosure provides an IV curve scanning method and related device.

[0006] To solve the above technical problems, the present disclosure adopts the following technical solutions:

[0007] An IV curve scanning method applied to an inverter in a photovoltaic system, the photovoltaic system further comprising at least one photovoltaic string connected to a direct current side of the inverter, each photovoltaic string being provided with a plurality of photovoltaic units connected in series, each photovoltaic unit comprising a power converter and at least one photovoltaic module connected in series;

[0008] The IV curve scanning method comprises:

[0009] In response to an IV curve scanning instruction, a target photovoltaic string corresponding to the IV curve scanning instruction is determined. The target photovoltaic string is a photovoltaic string to which a to-be-scanned module belongs, as indicated by the IV curve scanning instruction.

[0010] The string current of the target photovoltaic string is adjusted so that the string current of the target photovoltaic string is within a preset current range, and each current value in the preset current range is greater than a reference operating current of the target photovoltaic string. The reference operating current is the string current of the target photovoltaic string when the string current starts to be adjusted.

[0011] The power converter corresponding to the to-be-scanned module is controlled to perform an IV curve scanning operation on the to-be-scanned module, and a scanning result is obtained.

[0012] Optionally, adjusting the string current of the target photovoltaic string so that the string current of the target photovoltaic string is within a preset current range comprises:

[0013] directly regulating the string voltage of the target photovoltaic string to indirectly regulate the string current of the target photovoltaic string so that the string current of the target photovoltaic string is within the preset current range;

[0014] Or, directly regulating the string current of the target photovoltaic string so that the string current of the target photovoltaic string is within the preset current range.

[0015] Optionally, directly regulating the string voltage of the target photovoltaic string to indirectly regulate the string current of the target photovoltaic string so that the string current of the target photovoltaic string is within the preset current range comprises:

[0016] determining a target adjustment voltage less than a reference operating voltage of the target photovoltaic string; the reference operating voltage is the string voltage of the target photovoltaic string when the string voltage starts to be regulated;

[0017] gradually regulating the string voltage of the target photovoltaic string by using a component adjustment parameter to fix the string voltage of the target photovoltaic string in a preset voltage range not greater than the target adjustment voltage; when the string voltage of the target photovoltaic string is in the preset voltage range, the string current of the target photovoltaic string is in the preset current range.

[0018] Optionally, determining a target adjustment voltage less than a reference operating voltage of the target photovoltaic string comprises:

[0019] obtaining a reference operating voltage of the target photovoltaic string and a maximum input voltage of a power converter connected with the target photovoltaic string;

[0020] calculating a target adjustment voltage less than the reference operating voltage of the target photovoltaic string based on the reference operating voltage, the maximum input voltage, and a target adjustment voltage calculation formula.

[0021] Optionally, the component adjustment parameter comprises a regulation time.

[0022] gradually regulating the string voltage of the target photovoltaic string by using a component adjustment parameter comprises:

[0023] decreasing the string voltage of the target photovoltaic string according to a set decreasing speed within the regulation time.

[0024] Optionally, directly regulating the string current of the target photovoltaic string so that the string current of the target photovoltaic string is within the preset current range comprises:

[0025] determining a target adjustment current greater than a reference operating current of the target photovoltaic string;

[0026] The component adjustment parameter is used to gradually adjust the string current of the target photovoltaic string according to a set adjustment speed, so that the string current of the target photovoltaic string is fixed in a preset current range.

[0027] Optionally, the power converter corresponding to the to-be-scanned component is controlled to perform the IV curve scanning operation on the to-be-scanned component to obtain a scanning result, including:

[0028] The power converter corresponding to the to-be-scanned component is controlled to perform the IV curve scanning operation on the to-be-scanned component in series based on the arrangement order of the to-be-scanned component to obtain a scanning result.

[0029] Or, based on the attribute information of the inverter, a parallel scanning number is determined, and the power converter corresponding to the to-be-scanned component is controlled to perform the IV curve scanning operation on the corresponding to-be-scanned component in parallel based on the arrangement order of the to-be-scanned component to obtain a scanning result; wherein the number of to-be-scanned components scanned in parallel each time is the parallel scanning number.

[0030] Optionally, after the power converter corresponding to the to-be-scanned component is controlled to perform the IV curve scanning operation on the to-be-scanned component to obtain a scanning result, the IV curve scanning method further includes:

[0031] Based on the scanning result, a component fault analysis operation is performed.

[0032] Optionally, after the power converter corresponding to the to-be-scanned component is controlled to perform the IV curve scanning operation on the to-be-scanned component to obtain a scanning result, the IV curve scanning method further includes:

[0033] The component adjustment parameter is used to gradually reduce the string current of the target photovoltaic string until the string current of the target photovoltaic string is reduced to the reference operating current.

[0034] An IV curve scanning method applied to a power converter, the IV curve scanning method comprising:

[0035] Based on the control of the inverter, the connected to-be-scanned component is subjected to an IV curve scanning operation to obtain a scanning result; the inverter is configured to perform the above-mentioned IV curve scanning method.

[0036] Optionally, based on the control of the inverter, the connected to-be-scanned component is subjected to an IV curve scanning operation to obtain a scanning result, including:

[0037] In response to a scanning instruction issued by the inverter based on the arrangement order of the to-be-scanned component, the connected to-be-scanned component is subjected to an IV curve scanning operation in a serial or parallel manner to obtain a scanning result.

[0038] An inverter, comprising a controller, a boost circuit and an inverter circuit connected in sequence; a photovoltaic module string is connected to a DC side of the boost circuit, and another DC side of the boost circuit is connected to the inverter circuit through a DC bus;

[0039] The controller realizes the IV curve scanning operation by performing the IV curve scanning method.

[0040] A power converter is arranged between the inverter and the photovoltaic module, and realizes the IV curve scanning operation by performing the IV curve scanning method.

[0041] An IV curve scanning system comprises the inverter and the power converter.

[0042] The present disclosure has the following beneficial effects:

[0043] The present disclosure provides an IV curve scanning method and related devices, and the present disclosure no longer uses the method of scanning the IV curve of the entire module string when scanning, but directly uses the power converter corresponding to the to-be-scanned module to perform IV curve scanning operation on the to-be-scanned module to obtain the IV curve scanning result of the module. Compared with the IV curve of the entire module string, the IV curve scanning result of each module can more directly show the voltage and current scanning specific situation of each module, and the obtained IV curve of the module has high accuracy and meets the actual data requirements. In addition, the present disclosure increases the module string current of the target photovoltaic module string before performing the IV curve scanning, so that the current scanning range is larger during scanning, the scanning result is more in line with the actual current situation of the module, and the accuracy of the IV curve of the module is further improved.

[0044] BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present disclosure or the general technical scheme, the following will briefly introduce the drawings used in the embodiments or generally. Obviously, the drawings in the following description are only embodiments of the present disclosure, and those skilled in the art can obtain other drawings according to the provided drawings without creative labor.

[0046] FIG. 1 is a structure diagram of a photovoltaic system according to an embodiment of the present disclosure;

[0047] FIG. 2 is an installation schematic diagram of a power converter according to an embodiment of the present disclosure;

[0048] FIG. 3 is another installation schematic diagram of a power converter according to an embodiment of the present disclosure;

[0049] FIG. 4 is a flowchart of an IV curve scanning method according to an embodiment of the present disclosure;

[0050] Fig. 5 is a schematic diagram of an IV scan curve provided by an embodiment of the present disclosure;

[0051] Fig. 6 is a flowchart of a voltage regulation method provided by an embodiment of the present disclosure;

[0052] Fig. 7 is a schematic diagram of data variation provided by an embodiment of the present disclosure;

[0053] Fig. 8 is a flowchart of a current regulation method provided by an embodiment of the present disclosure;

[0054] Fig. 9 is a schematic diagram of a diagnostic result provided by an embodiment of the present disclosure;

[0055] Fig. 10 is a flowchart of another IV curve scan method provided by an embodiment of the present disclosure;

[0056] Fig. 11 is a schematic diagram of an operating scenario of an inverter provided by an embodiment of the present disclosure;

[0057] Fig. 12 is a schematic diagram of a structure of an IV curve scan system provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0058] The technical solutions in the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present disclosure.

[0059] A photovoltaic power station intelligent monitoring system can monitor a photovoltaic system, as shown in Fig. 1. The photovoltaic system is composed of photovoltaic strings, inverters and other devices. The strings are composed of a plurality of photovoltaic components in series. The number of components in each string can be different or the same according to the difference in open-circuit voltage of a single photovoltaic component and the difference in input voltage of the inverter. Boost1-m in the inverter receives the power input by the corresponding photovoltaic string. After the voltage is boosted in the Boost, the power is input to the inverter circuit through the positive (BUS+) and negative (BUS-) DC bus for DC-to-AC operation. The power output by the inverter circuit is subjected to voltage transformation through a transformer and then output to the power grid. A bus capacitor is configured between BUS+ and BUS-. In Fig. 1, m and x are positive integers and m≥x.

[0060] If the maximum power points of the photovoltaic strings in the photovoltaic array are inconsistent, or there are components with unmatched power in the photovoltaic system, the output power of the inverter will be reduced, thereby affecting the power generation efficiency. In severe cases, it may even cause normal photovoltaic components to deliver current to components with poor performance, forming hot spots.

[0061] In order to solve the above problems, the IV curve of the entire group string can be obtained, and the components with poor performance are screened based on the IV curve of the entire group string.

[0062] The IV curve obtained in this way is the IV curve of the entire group string, which cannot represent the IV curve of a certain component, thereby making the accuracy of the determined IV curve poor and unable to meet the actual data requirements.

[0063] Therefore, in the embodiments of the present disclosure, instead of scanning the IV curve of the entire group string, the power converter corresponding to the component to be scanned is directly used to perform IV curve scanning operation on the component to be scanned, so as to obtain the IV curve scanning result of the component. Compared with the IV curve of the entire group string, the IV curve scanning result of each component can more intuitively show the specific situation of voltage and current scanning of each component, and the obtained IV curve of the component has high accuracy and meets the actual data requirements. In addition, before performing the IV curve scanning, the group string current of the target photovoltaic group string is increased, so that the current scanning range during scanning is larger, the scanning result is more in line with the actual current situation of the component, and the accuracy of the IV curve of the component is further improved.

[0064] On the basis of the above, an embodiment of the present disclosure provides an IV curve scanning method, and the execution subject of the IV curve scanning method can be an inverter in a photovoltaic system.

[0065] In order to realize direct IV scanning of a single photovoltaic component or multiple photovoltaic components, a power converter can be installed between the photovoltaic component and the inverter. The power converter (such as a power optimizer) can realize the MPPT (Maximum power point tracking) function, can eliminate the series and parallel mismatch of the photovoltaic component, and has the IV curve scanning function of a single photovoltaic component.

[0066] In actual installation, the power converter can be installed on the photovoltaic component, as shown in FIG. 2. In FIG. 2, one power converter can be installed on each photovoltaic component, and the power converter performs IV scanning operation on the connected photovoltaic component. Multiple photovoltaic components can also be connected to the same power converter, and the power converter can perform IV curve scanning on one or more connected photovoltaic components in sequence or simultaneously. FIG. 2 only shows an example in which one power converter is connected to one photovoltaic component, and in actual application, multiple photovoltaic components can be connected to the same power converter according to actual conditions.

[0067] In FIG. 2, the power converter can be directly connected to the inverter, and the electrical energy output by the inverter is fed into the power grid.

[0068] Since the power converter has the IV curve scanning function of a single photovoltaic component, the IV curve scanning of all or part of the components can be realized by controlling each power converter. Since each component is scanned individually, the scanning result can represent the current operation of the component, and the accuracy of the IV curve obtained by scanning is high.

[0069] In actual application, referring to FIG. 3, the photovoltaic system further comprises at least one photovoltaic component string connected to the DC side of the inverter. FIG. 3 illustrates one photovoltaic component string as an example. Each photovoltaic component string is provided with a plurality of photovoltaic units connected in series. Each photovoltaic unit comprises a power converter and at least one photovoltaic component connected in series (the photovoltaic component in FIG. 3 can be blocked by a cloud or other blocking object). In FIG. 3, the power converter is connected to one photovoltaic component as an example. The power converters are connected in series and connected to the inverter. The inverter is connected to the power grid through AC.

[0070] The power converter in the embodiment has the MPPT function, can eliminate the series-parallel mismatch of the photovoltaic component, and has the IV curve scanning function of a single or multiple photovoltaic components. During scanning, based on the control of the inverter, single photovoltaic component scanning and multiple photovoltaic component parallel scanning operations are performed to obtain the IV curve of the corresponding photovoltaic component, and then corresponding fault diagnosis operations are performed based on the IV curve.

[0071] Based on the structure of FIG. 3, the inverter implements the IV curve scanning method in the disclosure.

[0072] Referring to FIG. 4, the IV curve scanning method can comprise:

[0073] S11, in response to an IV curve scanning instruction, determining a target photovoltaic component string corresponding to the IV curve scanning instruction.

[0074] The target photovoltaic component string is the photovoltaic component string to which the photovoltaic component to be scanned belongs, as indicated by the IV curve scanning instruction.

[0075] In actual application, the user can select the photovoltaic component to be scanned through an application program or a web page in the server. In the embodiment, all photovoltaic components can be selected, or part of the photovoltaic components can be selected. When part of the photovoltaic components are selected, one photovoltaic component or multiple photovoltaic components can be selected. The photovoltaic components in the same string or the photovoltaic components in different strings can be selected. The specific selection mode is configured according to actual requirements.

[0076] The photovoltaic module selected in this embodiment is called the to-be-scanned module. When the user selects, a photovoltaic module schematic diagram can be displayed, and the user can click the photovoltaic module to be scanned on the diagram or input the photovoltaic module number to determine the photovoltaic module to be scanned. After the user completes the selection, the user can click the confirmation instruction, and at this time, the inverter receives the IV curve scanning instruction, and the IV curve scanning instruction includes the indicated to-be-scanned module.

[0077] Then, the inverter responds to the IV curve scanning instruction to determine the target photovoltaic module string to which the current adjustment is required.

[0078] In actual application, determining the target photovoltaic module string corresponding to the IV curve scanning instruction includes:

[0079] 1) Obtain the composition relationship between the photovoltaic module and the photovoltaic module string.

[0080] Specifically, as shown in FIG. 3, the photovoltaic module string includes a photovoltaic unit, and the photovoltaic unit includes a power converter and at least one photovoltaic module in series. That is, the photovoltaic module string is composed of photovoltaic modules and other parts, and the photovoltaic module and the photovoltaic module string have a composition relationship, that is, which photovoltaic modules are included in the photovoltaic module string, for example, the photovoltaic module string 1 includes photovoltaic modules 01 and 02, and the photovoltaic module string 2 includes photovoltaic modules 03 and 04. In this embodiment, the composition relationship between the photovoltaic module and the photovoltaic module string can be obtained, and the target photovoltaic module string is determined based on the composition relationship. The composition relationship can be displayed in the form of a diagram as shown in FIG. 3, a table, text, or the like, which is not limited in this embodiment.

[0081] 2) From the composition relationship, determine the photovoltaic module string in which the to-be-scanned module is located.

[0082] Specifically, still taking FIG. 3 as an example, it is assumed that the to-be-scanned modules selected by the user are photovoltaic modules 01 and 03. Since the photovoltaic module 01 is located in the photovoltaic module string 1, and the photovoltaic module 03 is located in the photovoltaic module string 2, the photovoltaic module strings 1 and 2 are determined as the photovoltaic module strings.

[0083] If the composition relationship is displayed in the form of a table, the photovoltaic module 01 can be directly located from the table to find out the photovoltaic module string to which it belongs. The same applies when the composition relationship is displayed in the form of text.

[0084] 3) Determine the photovoltaic module string as the target photovoltaic module string.

[0085] After the photovoltaic module string is determined, the determined photovoltaic module string is taken as the target photovoltaic module string. In this embodiment, the target photovoltaic module string can be, for example, the photovoltaic module strings 1 and 2, and the photovoltaic module strings 1 and 2 can be highlighted to highlight the determined target photovoltaic module string.

[0086] S12, adjust the string current of the target photovoltaic string so that the string current of the target photovoltaic string is within a preset current range.

[0087] Each current value in the preset current range is greater than the reference operating current of the target photovoltaic string.

[0088] Specifically, when using a power converter to perform IV curve scanning, it is found that due to the voltage adjustment control of the inverter, the output of the entire string current is limited, which causes the power converter to be affected by the inverter limiting the string current when performing IV curve scanning, the current scanning range is small, and the current higher than the current limit of the string current cannot be scanned, so that the scanned current range is only a small part of the actual current range, so that the string IV curve scanning cannot obtain a complete IV curve, and the data completeness of the IV curve is low.

[0089] Therefore, before performing IV curve scanning, the disclosure can increase the current of the target photovoltaic string, so that the range interval of the string current is widened, the current scanning range during scanning is larger, and the scanning result is more in line with the actual range of the component current.

[0090] When increasing the current of the target photovoltaic string, there are two implementation methods, one is direct adjustment, and the other is indirect adjustment. When directly adjusting, the current of the target photovoltaic string is directly increased, and when indirectly adjusting, it is found that the relationship between the string voltage and the string current is analyzed, the string voltage decreases, and the string current increases, so that the current of the target photovoltaic string can be increased by reducing the voltage of the target photovoltaic string.

[0091] In addition, since the inverter controls the input voltage on the entire string, when the voltage is controlled, it is affected by the inverter tracking the maximum power point, or affected by weather, shading, etc., causing the voltage and current control on multiple strings to oscillate, at this time, if the power converter performs component IV curve scanning, the component IV curve scanning data will oscillate sharply. As shown in FIG. 5, the theoretical IV curve scanning curve is a smooth curve, but due to the influence of the inverter controlling the input voltage on the entire string, the IV curve scanning curve in the actual detection process is constantly oscillating, reducing the accuracy of data scanning, which may cause the output power of the photovoltaic system to fluctuate greatly, affecting the stability of the regional power system.

[0092] To this end, in order to improve the smoothness of the IV scan curve, before the IV scan is performed, after the string current of the target photovoltaic string is increased, the string current can be fixed in a preset current range. Therefore, in the embodiment, the string current is increased based on a reference operating current, and in the embodiment, the reference operating current is set to be the string current of the target photovoltaic string when the string current starts to be adjusted. In addition, in order to expand the current scan range, the sum of the string current of the target photovoltaic string when the string current starts to be adjusted and a set value can be used as the reference operating current, and the set value can be configured according to the actual current scan range.

[0093] Through the above operation, when the IV scan is performed, the string current is increased, and after the string current is increased, the current scan range during the scan is larger, and the scan result is more consistent with the actual range of the component.

[0094] In addition, during the scan, the string current is fixed in the preset current range, and each current value in the preset current range is greater than the reference operating current of the target photovoltaic string, so that the current is stabilized in a current interval, the string current fluctuates less during the scan, even if affected by the inverter tracking the maximum power point, or affected by the weather, shading, etc., causing the voltage and current control of multiple strings to oscillate, it can also be stabilized in an interval, avoiding the voltage oscillation amplitude being too large, so that the IV scan curve fluctuates less, and the scan result accuracy is improved.

[0095] In a possible implementation, the preset current range in the embodiment can be a single current value, and at this time, the string current is set to the single current value, and the target photovoltaic string enters a constant voltage or constant current mode. In the constant current mode, the string current is fixed. In the constant voltage mode, the string voltage is fixed, and at this time, the string current is also a fixed constant value.

[0096] In addition, the preset current range can also be a current interval composed of multiple current values, and the size of the current interval can be configured according to actual conditions. If the smoothness requirement is high, a smaller interval range can be selected, and if the smoothness requirement is not high, a larger interval range can be selected. At this time, during the IV scan, the target photovoltaic string is allowed to fluctuate up and down within the preset current range, but cannot exceed the preset current range.

[0097] S13, controlling the power converter corresponding to the to-be-scanned component to perform an IV curve scan operation on the to-be-scanned component to obtain a scan result.

[0098] In the embodiment, after the string current is adjusted, the IV curve scan operation is performed, and at this time, the inverter controls the power converter corresponding to the to-be-scanned component to perform an IV curve scan operation on the to-be-scanned component to obtain a scan result.

[0099] In order to improve the applicability of the present disclosure, both serial and parallel scanning modes are supported during scanning. In the serial mode, the plurality of photovoltaic components are scanned sequentially, and in the parallel mode, the plurality of photovoltaic components are scanned simultaneously.

[0100] In the serial scanning mode, the power converter corresponding to the component to be scanned can be controlled to perform the IV curve scanning operation on the component to be scanned based on the arrangement order of the component to be scanned, and the scanning result is obtained.

[0101] The arrangement order in the embodiment can be the order of the number of the component to be scanned, the order of the number of the photovoltaic string where the component to be scanned is located, random order, or a manually specified order.

[0102] In order to enable those skilled in the art to more clearly understand the IV scanning process in the present disclosure, an example of IV curve scanning operation in the constant voltage or constant current mode is given.

[0103] The inverter uses the PLC (Power Line Communication) communication mode to start to serially notify the power converter corresponding to the component to be scanned to perform the component IV curve scanning. The specific process is as follows:

[0104] The inverter issues the component IV curve scanning enable instruction to the power converter corresponding to the first component to be scanned according to the arrangement order of the component to be scanned. The power converter starts to scan, and after the scanning is completed, the inverter obtains the component IV curve scanning data, i.e., the scanning result. The inverter sends the IV curve scanning exit instruction to the power converter that has completed the scanning, and clears the data of the power converter.

[0105] Then, the component IV curve scanning enable instruction is issued to the power converter corresponding to the next component to be scanned, and the above steps are repeated until all the components to be scanned are scanned.

[0106] The above serial scanning mode has high stability and reliability, and has less impact on the voltage change of the inverter, but the scanning efficiency is low. Therefore, in another implementation mode of the present disclosure, in order to improve the scanning efficiency, the parallel scanning mode can be used.

[0107] In the parallel scanning mode, the number of parallel scanning is determined. In the embodiment, when the plurality of photovoltaic components are scanned simultaneously, the current of the plurality of photovoltaic components changes constantly, and the voltage changes constantly. If the number of components scanned simultaneously is large, the voltage of the inverter will change constantly, which is unstable and affects the operation of the inverter, thereby adversely affecting the power generation process. Therefore, in the embodiment, the number of photovoltaic components scanned simultaneously is limited.

[0108] In practical applications, the number of parallel scans can be determined based on the attribute information of the inverter. For example, the number of parallel scans can be determined based on the voltage fluctuation that the inverter can withstand. For example, if an inverter is connected to 20 photovoltaic components, and half of the photovoltaic components fluctuate in voltage without affecting the inverter, then the number of parallel scans is 10. If one fourth of the photovoltaic components fluctuate in voltage without affecting the inverter, then the number of parallel scans is 5.

[0109] The number of parallel scans can also be determined by the user based on experience. In addition, the number of parallel scans can also be achieved by using a model for prediction, such as a neural network model or a deep learning model.

[0110] After determining the number of parallel scans, the corresponding power converter of the to-be-scanned component is controlled to perform an IV curve scanning operation on the corresponding to-be-scanned component in parallel based on the arrangement order of the to-be-scanned component, and a scanning result is obtained.

[0111] Specifically, during actual scanning, the number of to-be-scanned components scanned in parallel each time is the number of parallel scans.

[0112] To be specific, in actual scanning, the number of to-be-scanned components scanned in parallel each time is the number of parallel scans.

[0113] If some power converters scan faster during parallel scanning, the next power converter on this parallel route continues to scan after the scanning of the power converter is completed, and all parallel routes are processed in this manner until all to-be-scanned IV curve scanning is completed.

[0114] In a possible implementation, if all the photovoltaic components connected to a power converter are scanned, the power converter can be controlled by the inverter to scan in parallel or sequentially in parallel.

[0115] In a possible implementation, to avoid the problem of large storage capacity caused by data accumulation, the power converter data can be cleared after the power converter completes scanning.

[0116] In a possible implementation, to balance the scanning efficiency and scanning stability, serial IV scanning can be performed first, and if it is found that the scanning task cannot be completed on time, parallel IV scanning can be performed. Alternatively, parallel IV scanning can be performed first, and if it is found that the scanning task can be completed on time, serial IV scanning can be performed.

[0117] In this embodiment, during scanning, instead of scanning the IV curve of the entire string, the power converter corresponding to the component to be scanned is directly used to perform IV curve scanning operation on the component to be scanned, so as to obtain the IV curve scanning result of the component. Compared with the IV curve of the entire string, the IV curve scanning result of each component can more directly show the voltage and current scanning specific situation of each component, and the obtained IV curve of the component has high accuracy and meets the actual data requirement. In addition, before performing the IV curve scanning, the string current of the target photovoltaic string is increased, so that the current scanning range during scanning is larger, and the scanning result is more in line with the actual current situation of the component, thereby further improving the accuracy of the IV curve of the component.

[0118] The above embodiment mentions adjusting the string current of the target photovoltaic string so that the string current of the target photovoltaic string is located within the preset current range. In the embodiment of the present disclosure, two adjustment modes of the string current are given, which will be introduced as follows.

[0119] 1. The string voltage of the target photovoltaic string is directly adjusted to indirectly adjust the string current of the target photovoltaic string, so that the string current of the target photovoltaic string is located within the preset current range.

[0120] In actual application, for a target photovoltaic string, the corresponding string voltage changes, and the string current changes accordingly. Therefore, the adjustment of the string voltage can indirectly realize the adjustment of the string current.

[0121] In actual application, the string voltage of the target photovoltaic string is directly adjusted to indirectly adjust the string current of the target photovoltaic string, so that the string current of the target photovoltaic string is located within the preset current range. This can be specifically realized through the following steps in FIG. 6.

[0122] S21, determining a target adjustment voltage smaller than a reference operating voltage of the target photovoltaic string.

[0123] The reference operating voltage is the string voltage of the target photovoltaic string when the string voltage starts to be adjusted.

[0124] In specific implementation, the photovoltaic component has the characteristics of voltage drop and current rise. For a target photovoltaic string, the string voltage decreases and the string current increases. Therefore, in order to increase the string current, the string voltage of the target photovoltaic string should be reduced in this embodiment. Therefore, the inverter can adjust the maximum value of the current scanning range during IV curve scanning by reducing the string voltage of the target photovoltaic string where the component to be scanned is located, so as to avoid the problem that the incomplete component IV curve scanning data is caused by the current limiting of the power converter.

[0125] In the process of reducing the string voltage, a reference voltage is set to determine the degree of reduction of the string voltage, and the reference voltage in the embodiment is the reference operating voltage, which is the string voltage of the target photovoltaic string when the string voltage starts to be adjusted. In addition, it can also be an artificially set voltage value based on experience, or the difference between the string voltage of the target photovoltaic string when the string voltage starts to be adjusted and a set value as the reference operating voltage.

[0126] In practical applications, the target adjustment voltage should be less than the reference operating voltage of the target photovoltaic string to improve the current scanning range. Therefore, the reference operating voltage of the target photovoltaic string should be reduced to obtain the target adjustment voltage.

[0127] In specific implementation, the target adjustment voltage can be calculated based on the reference operating voltage of the target photovoltaic string. For example, the reference operating voltage / n is taken as the target adjustment voltage. Wherein, n is a positive integer, which can be configured according to actual needs. If a larger current scanning range is desired, the value of n should be larger, that is, n is positively correlated with the maximum value of the current scanning range. Or the difference between the reference operating voltage and a specified voltage value is taken as the target adjustment voltage.

[0128] Alternatively, in the calculation of the target adjustment voltage, the maximum input voltage of the power converter connected to the target photovoltaic string can also be introduced.

[0129] Wherein, the maximum input voltage of the power converter refers to the maximum value of the input voltage of all photovoltaic strings connected to the power converter, and the input voltage of all photovoltaic strings can be directly obtained to select the maximum value.

[0130] Therefore, in the embodiment, after obtaining the reference operating voltage of the target photovoltaic string (which can be obtained by acquisition) and the maximum input voltage of the power converter connected to the target photovoltaic string, the target adjustment voltage less than the reference operating voltage of the target photovoltaic string is calculated based on the reference operating voltage, the maximum input voltage and the target adjustment voltage calculation formula.

[0131] Specifically, the target adjustment voltage calculation formula includes the correlation between the reference operating voltage, the maximum input voltage and the target adjustment voltage. The calculation formula can be as follows:

[0132] Target adjustment voltage=(reference operating voltage-maximum operating voltage / m)

[0133] Wherein, m is a positive integer, and if a larger current scanning range is desired, the value of m should be smaller, and m can be 0.7. In addition, the value of m can also be set according to actual conditions.

[0134] In an implementation, the target regulation voltage calculation formula can also be adjusted according to actual configurations, for example, the value of m can be changed, or the maximum operating voltage / m can be adjusted to the maximum operating voltage multiplied by w, and the value of w can be adjusted according to actual configurations.

[0135] Through the diversified ways of determining the target regulation voltage in the embodiments of the present disclosure, a corresponding way can be selected according to actual conditions, and the adaptability to scenes is strong.

[0136] S22, gradually adjust the string voltage of the target photovoltaic string by using the component adjustment parameter, so as to fix the string voltage of the target photovoltaic string in a preset voltage range not greater than the target regulation voltage; when the string voltage of the target photovoltaic string is in the preset voltage range, the string current of the target photovoltaic string is in the preset current range.

[0137] After the inverter determines the target regulation voltage, the next step is to adjust the string voltage. In the adjustment, the voltage of the corresponding target photovoltaic string is set to be in a preset voltage range not greater than the target regulation voltage. The preset voltage range can be a constant value, for example, the target regulation voltage. If the control voltage is constant, the constant voltage mode is entered. The constant voltage mode refers to that the voltage of the target photovoltaic string is stable at a voltage value not greater than the target regulation voltage, and the voltage does not change.

[0138] The preset voltage range can also be a voltage range. The preset voltage range can be adjusted according to actual configurations, and can be in any sub-interval of [0-target regulation voltage], for example, a voltage range close to and not greater than the target regulation voltage.

[0139] In actual application, in order to avoid the situation that the inverter voltage is unstable due to large fluctuation in voltage adjustment, the component adjustment parameter is used to gradually adjust the voltage or current of the target photovoltaic string until the voltage of the target photovoltaic string is reduced to the preset voltage range not greater than the target regulation voltage, and then the adjustment is stopped. If the string voltage of the target photovoltaic string is in the preset voltage range, the string current of the target photovoltaic string is in the preset current range.

[0140] After the voltage adjustment, i.e., the voltage of the target photovoltaic string is adjusted in the preset voltage range, the voltage of the target photovoltaic string is controlled to be constant or fluctuate in the preset voltage range to realize subsequent IV scanning. If the voltage fluctuation is allowed, the voltage change can be monitored. If the voltage is still in the preset voltage range, the voltage is not adjusted. If the voltage is out of the preset voltage range, the voltage is adjusted so that the voltage is in the preset voltage range again. Even if the voltage and current control of multiple strings are affected by the inverter tracking the maximum power point or affected by weather, shading, etc., the voltage can be stabilized in an interval to avoid large voltage fluctuation.

[0141] The component adjustment parameter can be configured according to actual conditions, such as including an adjustment time. The voltage is adjusted according to the adjustment time. In the specific adjustment, the component adjustment parameter can include a descending speed in addition to the adjustment time. The descending speed can be uniform or variable. In this embodiment, the string voltage of the target photovoltaic string is reduced according to the set descending speed in the adjustment time. In addition, the component adjustment parameter can not include the adjustment time but only include the descending speed. The descending speed can be uniform or variable. The adjustment speed can be set by experience by a person, can be obtained by analyzing voltage adjustment cases to obtain a speed with good voltage adjustment stability, or can be realized by model prediction.

[0142] Referring to FIG. 7, after the target adjustment voltage is calculated, the inverter can start to control the voltage to decrease, and the current is adjusted accordingly. In actual application, the current is decreased to the required value in the adjustment time. During the decreasing process, it is determined in real time whether the voltage after the decrease is in the preset voltage range that is not greater than the target adjustment voltage. If not, the voltage is continuously decreased. If yes, the voltage adjustment operation is stopped, and then the voltage of the target photovoltaic string is fixed as the target adjustment voltage to enter the constant voltage mode or allow the voltage to fluctuate.

[0143] Taking the constant voltage mode as an example, after the constant voltage mode is performed, the power converter can start to perform the current-voltage (IV) curve scanning operation on the component to be scanned.

[0144] In the above embodiment, the component adjustment parameter is the adjustment time. In addition, the component adjustment parameter can include the descending speed. When the adjustment time and the descending speed are included at the same time, the voltage is adjusted according to the descending speed in the adjustment time until the voltage is adjusted to the required value. When the component adjustment parameter only includes the descending speed, the voltage value is directly reduced according to the descending speed, and the time length is not required.

[0145] After the voltage is adjusted to the preset voltage range, the IV scanning operation can be performed.

[0146] In another implementation of the present disclosure, after the power converter corresponding to the component to be scanned controls the component to be scanned to perform the IV curve scanning operation to obtain the scanning result, the component adjustment parameter is used to gradually reduce the string current of the target photovoltaic string until the string current of the target photovoltaic string is reduced to the reference operating current.

[0147] In the embodiment, after the IV scanning is completed, the string current is adjusted back to the original current, that is, the reference operating current, so as to not affect the normal operation of the inverter. Since the string current is increased before the IV scanning is performed, the string current is reduced after the IV scanning is completed. When the string current is reduced, the string adjustment parameter, such as the adjustment time described above, can be used for adjustment.

[0148] For example, in the case of indirectly adjusting the current by the voltage, after the IV scanning is completed, the voltage of the target photovoltaic string is adjusted to the reference operating voltage.

[0149] Specifically, the voltage adjustment process of the present step is the reverse operation of the voltage adjustment process described above. The voltage of the target photovoltaic string can be gradually increased until the voltage of the target photovoltaic string is increased to the reference operating voltage.

[0150] In actual application, referring to FIG. 7, the adjustment time for adjusting the voltage to decrease and the adjustment time for adjusting the voltage to increase can both be fixed time. The waveforms of the voltage and the current controlled by the inverter in the component IV curve scanning stage are shown in FIG. 7.

[0151] In addition, when the voltage is increased, the voltage value can also be increased according to a preset increasing speed. Which way is used depends on actual configuration.

[0152] By increasing the voltage, the voltage of the target photovoltaic string can be increased to the voltage before the scanning. Subsequently, the inverter can use the maximum power tracking method to adjust the voltage of the string to achieve the maximum power generation.

[0153] 2. Directly adjusting the string current of the target photovoltaic string to make the string current of the target photovoltaic string be within the preset current range.

[0154] When the string current of the target photovoltaic string is directly adjusted, the same as the voltage adjustment described above, referring to FIG. 8, it can include:

[0155] S31, determining a target adjustment current greater than the reference operating current of the target photovoltaic string.

[0156] The target adjustment current can also be set with a corresponding calculation formula as the target adjustment voltage described above. The specific calculation formula can be configured according to actual configuration.

[0157] S32, gradually adjust the string current of the target photovoltaic string according to the set adjustment speed by using the component adjustment parameter, so as to fix the string current of the target photovoltaic string in the preset current range.

[0158] The string current adjustment process is similar to the string voltage. The adjustment time and / or adjustment speed can be set, and the corresponding string current adjustment operation is performed, so that the string current of the target photovoltaic string is fixed in the preset current range, and then the IV curve scanning operation is performed. After the scanning is completed, the string current is reduced until it is raised to the reference operating current. The subsequent inverter can use the maximum power tracking method to achieve the maximum power generation.

[0159] In this embodiment, the adjustment of voltage and current is used to realize the increase of string current, so as to expand the current scanning range and improve the data integrity during the IV curve scanning of the component.

[0160] In another implementation of the present disclosure, after the power converter corresponding to the component to be scanned is controlled to perform the IV curve scanning operation on the component to be scanned to obtain the scanning result, a component fault analysis operation can also be performed based on the scanning result.

[0161] Specifically, the intelligent diagnosis algorithm can be used to analyze the scanning result. The scanning result can refer to FIG. 9 and be divided into three diagnostic results: one is normal, one is component current mismatch, and the other is test abnormality. That is, through the scanning result in the present disclosure, the diagnostic result of the specific component can be directly diagnosed, so as to find the component with poor performance for replacement or maintenance operation.

[0162] Specifically, through the intelligent diagnosis algorithm, the aging degree and operating state of the string are detected, such as bypass diode short circuit, string shading, component current mismatch, etc. Based on the aging degree and operating state of the string, the component with power mismatch can be inferred. When the component with power mismatch is inferred, the component with power mismatch can be manually determined from the detected string based on experience, and the corresponding replacement or maintenance operation is performed, so as to increase the power generation of the photovoltaic system and reduce the operation and maintenance cost.

[0163] In this embodiment, the IV scanning curve with high accuracy can be obtained through the above steps. Then, the intelligent diagnosis using the curve can also improve the intelligent diagnosis result, and the component with power mismatch in the string can be accurately determined through the IV curve obtained by scanning, and the replacement operation is performed, thereby improving the component fault diagnosis accuracy.

[0164] The intelligent diagnosis algorithm can be implemented in various ways such as formula, artificial intelligence model, etc.

[0165] In addition, in order to avoid the problem of low accuracy of diagnostic results caused by errors of intelligent diagnostic algorithms, two or more different intelligent diagnostic algorithms can be used to analyze the scanning results at the same time, and the results are fused to obtain diagnostic results with higher accuracy.

[0166] In addition, after obtaining the diagnostic results by using the intelligent diagnostic algorithm, the diagnostic results can be output to the artificial for checking to ensure the accuracy and reliability of the diagnostic results.

[0167] In order to enable those skilled in the art to have a clearer understanding of the present disclosure, taking the constant voltage mode as an example, the detailed implementation process of the present disclosure is explained and described in combination with FIG. 10.

[0168] 1. The user can issue an IV curve scanning instruction through an application program or a web page on the server, and the IV curve scanning instruction includes a to-be-scanned component. After receiving the instruction, the inverter responds to the instruction and feeds back to the user.

[0169] 2. The inverter performs voltage regulation operation, specifically, the string voltage of the to-be-scanned component is lowered to ensure that the power converter will not be limited by the current to cause incomplete component IV curve scanning data.

[0170] Specifically, after receiving the to-be-scanned component data issued by the inverter, the inverter suspends other power regulation functions, calls the IV curve scanning program, and calculates the voltage of the string constant voltage mode. The specific calculation formula can be:

[0171] The current string voltage-current string power converter maximum input voltage / 0.7.

[0172] During the calculation process, the inverter determines:

[0173] 1) Which string voltage keeps constant voltage mode.

[0174] 2) The voltage corresponding to the string constant voltage mode.

[0175] After the inverter obtains the above data, it controls the corresponding string voltage to the specified voltage.

[0176] The inverter controls the voltage waveform during the component IV curve scanning stage as shown in FIG. 6. The adjustment voltage falling time can be a fixed time, and the adjustment voltage rising time is also a fixed time.

[0177] 3. The inverter interacts with the power converter to start the component IV curve scanning operation.

[0178] In the constant voltage mode, the inverter uses PLC communication to start serially notifying the power converter of the to-be-scanned component to perform component IV curve scanning. The specific process is as follows:

[0179] (1) The inverter sends a component IV curve scanning enable instruction to the corresponding power converter.

[0180] (2) The inverter obtains the completed component IV curve scanning data.

[0181] (3) The inverter sends an IV curve scanning exit instruction to the optimizer of the current scanning, and the optimizer data can be cleared to avoid the problem of large storage caused by data accumulation.

[0182] Then the above (1)-(3) process is repeated until all the components to be scanned are completed.

[0183] 4. The inverter performs voltage adjustment operation, specifically, restoring the string voltage of the component to be scanned.

[0184] After the power converter completes the component IV curve scanning, the inverter restores the voltage to the state before the component IV curve scanning. The adjustment process is similar to the above process of lowering the voltage. After the voltage is raised, the original power adjustment operation can be restored.

[0185] After the inverter receives the scanning result polling instruction of the user, the inverter transmits the component IV curve scanning data of the power converter to the server based on the transmission protocol, so that the server can visualize the data and make algorithm diagnosis.

[0186] In this embodiment, in the case of continuous change of light and other conditions, the voltage is lowered to expand the current scanning range and improve the data integrity during component IV curve scanning. In addition, the voltage of the component to be scanned is fixed to a fixed position or within a certain voltage range based on the constant voltage mode, which can ensure that the data of the component IV curve scanning interval is not disturbed by the external environment, and the IV curve scanning waveform of the component is closer to the actual situation, providing an effective basis for subsequent component diagnosis. The component diagnosis is more reliable, stable and accurate.

[0187] On the basis of the above-mentioned embodiment of the IV curve scanning method applied to the inverter, another embodiment of the present disclosure provides an IV curve scanning method applied to the power converter, the IV curve scanning method comprising:

[0188] Based on the control of the inverter, the connected component to be scanned is subjected to IV curve scanning operation to obtain scanning results; the inverter is configured to execute the above-mentioned IV curve scanning method applied to the inverter.

[0189] Specifically, based on the control of the inverter, when the IV curve scanning operation is performed on the connected to-be-scanned components to obtain the scanning result, the inverter issues the scanning instruction based on the arrangement order of the to-be-scanned components, and the IV curve scanning operation is performed on the connected to-be-scanned components in a serial or parallel manner to obtain the scanning result. For specific implementation process, refer to the corresponding description above.

[0190] In this embodiment, by increasing the current before the IV curve scanning is performed and limiting the current in a certain current range, the IV scanning range can be expanded, the external interference can be reduced, and the IV scanning accuracy of the power converter can be improved.

[0191] On the basis of the above-mentioned embodiment of the IV curve scanning method, another embodiment of the present disclosure provides an inverter, which comprises a controller, a boost circuit and an inverter circuit connected in sequence; a photovoltaic module string is connected to a direct current side of the boost circuit, and another direct current side of the boost circuit is connected with the inverter circuit through a direct current bus;

[0192] The controller performs the above-mentioned IV curve scanning method to realize the IV curve scanning operation.

[0193] Referring to FIG. 11, in FIG. 11, the controller is connected with each Boost and inverter circuit, and the connection relationship among the controller, the Boost and the inverter circuit is not shown in FIG. 11 to avoid complex wiring. The controller can control the Boost and the inverter circuit to operate to realize the boost and inverter operations of the electric energy generated by the photovoltaic module string, and finally output the electric energy to the power grid.

[0194] In a possible implementation, in order to avoid interference, a filter circuit can be arranged in the inverter circuit to realize the filtering function.

[0195] On the basis of the above-mentioned embodiment of the IV curve scanning method, another embodiment of the present disclosure provides a power converter arranged between the inverter and the photovoltaic module, which realizes the IV curve scanning operation through the above-mentioned IV curve scanning method.

[0196] On the basis of the above-mentioned embodiment of the inverter and the power converter, another embodiment of the present disclosure provides an IV curve scanning system, which comprises the above-mentioned inverter 102 and the above-mentioned power converter 101, as shown in FIG. 12.

[0197] The above description of disclosed embodiments allows a skilled person to implement or use the disclosure. Numerous modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit or scope of the disclosure. Therefore, the disclosure 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. An IV curve scanning method, wherein, An inverter used in a photovoltaic system, the photovoltaic system further comprising at least one photovoltaic string connected to the DC side of the inverter, each photovoltaic string comprising a plurality of photovoltaic units connected in series, each photovoltaic unit comprising a power converter connected in series and at least one photovoltaic module; The IV curve scanning method includes: In response to the IV curve scanning command, the target photovoltaic string corresponding to the IV curve scanning command is determined; the target photovoltaic string is the photovoltaic string to which the component to be scanned indicated by the IV curve scanning command belongs; The string current of the target photovoltaic string is adjusted so that the string current of the target photovoltaic string is within a preset current range, wherein each current value in the preset current range is greater than the reference operating current of the target photovoltaic string; the reference operating current is the string current of the target photovoltaic string when the string current adjustment begins. The power converter corresponding to the component to be scanned is controlled to perform an IV curve scanning operation on the component to be scanned, and the scanning result is obtained.

2. The IV curve scanning method according to claim 1, wherein, Adjusting the string current of the target photovoltaic string to bring it within a preset current range includes: The string voltage of the target photovoltaic string is directly adjusted to indirectly adjust the string current of the target photovoltaic string, so that the string current of the target photovoltaic string is within a preset current range. Alternatively, the string current of the target photovoltaic string can be directly adjusted so that the string current of the target photovoltaic string is within a preset current range.

3. The IV curve scanning method according to claim 2, wherein, Directly adjusting the string voltage of the target photovoltaic string to indirectly adjust the string current of the target photovoltaic string, so that the string current of the target photovoltaic string is within a preset current range, includes: A target adjustment voltage is determined that is lower than the reference operating voltage of the target photovoltaic string; the reference operating voltage is the string voltage of the target photovoltaic string when the string voltage adjustment begins; By utilizing component adjustment parameters, the string voltage of the target photovoltaic string is gradually adjusted to fix the string voltage of the target photovoltaic string within a preset voltage range that is not greater than the target adjustment voltage. The target photovoltaic string is within the preset voltage range when the string voltage is within the preset current range.

4. The IV curve scanning method according to claim 3, wherein, Determining a target regulation voltage that is less than the reference operating voltage of the target photovoltaic string includes: Obtain the reference operating voltage of the target photovoltaic string and the maximum input voltage of the power converter connected to the target photovoltaic string; Based on the reference operating voltage, the maximum input voltage, and the target adjustment voltage calculation formula, the target adjustment voltage, which is less than the reference operating voltage of the target photovoltaic string, is calculated.

5. The IV curve scanning method according to claim 3 or 4, wherein, The component adjustment parameters include adjustment time; By utilizing component adjustment parameters, the string voltage of the target photovoltaic string is gradually adjusted, including: During the adjustment period, the string voltage of the target photovoltaic string is reduced at a set decreasing rate.

6. The IV curve scanning method according to claim 2, wherein, Directly adjusting the string current of the target photovoltaic string to bring it within a preset current range includes: Determine a target regulating current that is greater than the reference operating current of the target photovoltaic string; By using component adjustment parameters, the string current of the target photovoltaic string is gradually adjusted according to the set adjustment speed, so that the string current of the target photovoltaic string is fixed within a preset current range.

7. The IV curve scanning method according to any one of claims 1-6, wherein, Control the power converter corresponding to the component to be scanned to perform an IV curve scanning operation on the component to be scanned, and obtain the scanning results, including: Based on the arrangement order of the components to be scanned, the power converters corresponding to the components to be scanned are serially controlled to perform IV curve scanning operations on the components to be scanned, and the scanning results are obtained. Alternatively, based on the inverter's attribute information, the number of parallel scans is determined, and based on the arrangement order of the components to be scanned, the power converters corresponding to the components to be scanned are controlled to perform IV curve scanning operations on the corresponding components to be scanned in parallel to obtain the scanning results; wherein, the number of components to be scanned in each parallel scan is the number of parallel scans.

8. The IV curve scanning method according to any one of claims 1-7, wherein, After controlling the power converter corresponding to the component to be scanned to perform an IV curve scanning operation on the component to be scanned and obtaining the scanning result, the IV curve scanning method further includes: Component fault analysis is performed based on the scan results.

9. The IV curve scanning method according to any one of claims 1-8, wherein, After controlling the power converter corresponding to the component to be scanned to perform an IV curve scanning operation on the component to be scanned and obtaining the scanning result, the IV curve scanning method further includes: By adjusting the component parameters, the string current of the target photovoltaic string is gradually reduced until it drops to the reference operating current.

10. An IV curve scanning method, wherein, The IV curve scanning method, applied to power converters, includes: Based on the control of the inverter, an IV curve scanning operation is performed on the connected components to be scanned to obtain the scanning result; the inverter is configured to perform the IV curve scanning method as described in any one of claims 1-9.

11. The IV curve scanning method according to claim 10, wherein, Based on inverter control, an IV curve scanning operation is performed on the connected components to be scanned to obtain the scanning results, including: In response to the scanning command issued by the inverter based on the arrangement order of the components to be scanned, the connected components to be scanned are subjected to IV curve scanning operation in a serial or parallel manner to obtain the scanning result.

12. An inverter, wherein, The inverter includes a controller, a boost circuit and an inverter circuit connected in sequence; the DC side of the boost circuit is connected to the photovoltaic string, and the other DC side of the boost circuit is connected to the inverter circuit through a DC bus. The controller performs the IV curve scanning operation by executing the IV curve scanning method as described in any one of claims 1-9.

13. A power converter, wherein, The power converter is positioned between the inverter and the photovoltaic module, and the IV curve scanning operation is achieved by the IV curve scanning method as described in any one of claims 10-11.

14. An IV curve scanning system, wherein, It includes the inverter as described in claim 12 and the power converter as described in claim 13.

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