CN116827263A

CN116827263A - Photovoltaic cell fault detection method, device, computer equipment and medium

Info

Publication number: CN116827263A
Application number: CN202310750918.7A
Authority: CN
Inventors: 陈怡静; 郭小江; 李春华; 孙栩; 申旭辉; 李铮; 张钧阳; 彭程; 赵华星; 车延博
Original assignee: Tianjin University; Huaneng Clean Energy Research Institute
Current assignee: Tianjin University; Huaneng Clean Energy Research Institute
Priority date: 2023-06-25
Filing date: 2023-06-25
Publication date: 2023-09-29

Abstract

The disclosure provides a photovoltaic cell fault detection method, a device, computer equipment and a medium, wherein the method comprises the following steps: the method comprises the steps of obtaining a real-time open-circuit voltage value, a real-time short-circuit current value, a target voltage value and a target current value of a photovoltaic cell at fault detection time, wherein the real-time open-circuit voltage value and the real-time short-circuit current value form a real-time feature array together, determining a reference feature array matched with the real-time feature array from a preset feature library, determining a real-time error variable according to the target voltage value, the target current value and the reference voltage value and the reference current value corresponding to the matched reference feature array in the preset feature library, and determining a fault detection result of the photovoltaic cell according to the real-time error variable. By implementing the method disclosed by the invention, the fault detection result of the photovoltaic cell can be rapidly and accurately obtained based on the voltage data characteristic and the current data characteristic of the photovoltaic cell, thereby effectively improving the operation reliability and economy of the photovoltaic power station.

Description

Photovoltaic cell fault detection method, device, computer equipment and medium

Technical Field

The disclosure relates to the technical field of intelligent fault diagnosis of battery energy storage systems, in particular to a photovoltaic cell fault detection method, a photovoltaic cell fault detection device, computer equipment and a photovoltaic cell fault detection medium.

Background

Fossil energy has double crisis of limited reserves and environmental pollution during use, clean energy sources such as photovoltaic, wind power, nuclear power, hydropower and the like are required to replace fossil energy sources for power generation, and the photovoltaic has great potential due to cost advantages. Distributed photovoltaic has been rapidly developed in recent years, and has become the dominant force for newly increasing the installed capacity of photovoltaic in the world. And the solar cell works in a severe natural environment for a long time, so that the solar cell is extremely prone to faults. If the faults of the photovoltaic power generation system cannot be diagnosed and processed in time, the photovoltaic module can be permanently damaged, and fire disaster is more serious.

In the related art, when the photovoltaic cell is subjected to fault detection, higher time cost is required, and the fault detection accuracy is lower.

Disclosure of Invention

The present disclosure aims to solve, at least to some extent, one of the technical problems in the related art.

Therefore, the purpose of the disclosure is to provide a method, a device, a computer device and a medium for detecting faults of a photovoltaic cell, which can rapidly and accurately obtain the fault detection result of the photovoltaic cell based on the voltage data characteristic and the current data characteristic of the photovoltaic cell, thereby effectively improving the reliability and the economy of the operation of a photovoltaic power station.

To achieve the above object, a method for detecting a failure of a photovoltaic cell according to an embodiment of the first aspect of the present disclosure includes:

acquiring a real-time open-circuit voltage value, a real-time short-circuit current value, a target voltage value and a target current value of a photovoltaic cell at a fault detection moment, wherein the real-time open-circuit voltage value and the real-time short-circuit current value form a real-time characteristic array together, and the target voltage value and the target current value are an output voltage value and an output current value of the photovoltaic cell when the photovoltaic cell is at maximum output power under a working condition corresponding to the real-time characteristic array;

determining a reference feature array matched with the real-time feature array from a preset feature library, wherein the preset feature library comprises a plurality of reference feature arrays, and a reference voltage value and a reference current value corresponding to each reference feature array, the reference feature arrays comprise a reference open-circuit voltage value and a reference short-circuit current value, and the reference voltage value and the reference current value are output voltage values and output current values of the photovoltaic cell under the condition that the reference feature arrays correspond to maximum output power;

determining a real-time error variable according to the target voltage value, the target current value and the reference voltage value and the reference current value corresponding to the matched reference feature array in the preset feature library;

And determining a fault detection result of the photovoltaic cell according to the real-time error variable.

To achieve the above object, a photovoltaic cell fault detection apparatus according to an embodiment of a second aspect of the present disclosure includes:

the device comprises an acquisition module, a control module and a control module, wherein the acquisition module is used for acquiring a real-time open-circuit voltage value, a real-time short-circuit current value, a target voltage value and a target current value of a photovoltaic cell at a fault detection moment, wherein the real-time open-circuit voltage value and the real-time short-circuit current value form a real-time characteristic array together, and the target voltage value and the target current value are an output voltage value and an output current value of the photovoltaic cell under a maximum output power under a working condition corresponding to the real-time characteristic array;

the first determining module is used for determining a reference feature array matched with the real-time feature array from a preset feature library, wherein the preset feature library comprises a plurality of reference feature arrays, and a reference voltage value and a reference current value corresponding to each reference feature array, the reference feature arrays comprise a reference open-circuit voltage value and a reference short-circuit current value, and the reference voltage value and the reference current value are output voltage values and output current values of the photovoltaic cell under the condition of maximum output power under the working condition corresponding to the reference feature array;

The second determining module is used for determining a real-time error variable according to the target voltage value, the target current value and the reference voltage value and the reference current value corresponding to the matched reference feature array in the preset feature library;

and the third determining module is used for determining a fault detection result of the photovoltaic cell according to the real-time error variable.

Embodiments of the third aspect of the present disclosure provide a computer device, including: the photovoltaic cell fault detection method comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor is used for realizing the photovoltaic cell fault detection method according to the embodiment of the first aspect of the present disclosure when executing the program.

An embodiment of a fourth aspect of the present disclosure proposes a non-transitory computer-readable storage medium, on which a computer program is stored, which when executed by a processor implements a photovoltaic cell failure detection method as proposed by an embodiment of the first aspect of the present disclosure.

Embodiments of a fifth aspect of the present disclosure propose a computer program product, which when executed by a processor, performs a photovoltaic cell failure detection method as proposed by embodiments of the first aspect of the present disclosure.

According to the photovoltaic cell fault detection method, device, computer equipment and storage medium, a real-time open-circuit voltage value, a real-time short-circuit current value, a target voltage value and a target current value of a photovoltaic cell at fault detection time are obtained, wherein the real-time open-circuit voltage value and the real-time short-circuit current value jointly form a real-time characteristic array, the target voltage value and the target current value are output voltage values and output current values of the photovoltaic cell when the photovoltaic cell is at maximum output power under the working condition corresponding to the real-time characteristic array, a reference characteristic array matched with the real-time characteristic array is determined from a preset characteristic library, the preset characteristic library comprises a plurality of reference characteristic arrays, and reference voltage values and reference current values corresponding to each reference characteristic array, the reference characteristic array comprises reference open-circuit voltage values and reference short-circuit current values, the reference voltage values and the reference current values are output voltage values and output current values of the photovoltaic cell when the photovoltaic cell is at maximum output power under the working condition corresponding to the reference characteristic array, real-time error variables are determined according to the target voltage values, the target current values and the reference voltage values and the reference current values corresponding to the matched reference characteristic arrays in the preset characteristic library, and the real-time error variables are determined according to the real-time error variables, and therefore, fault detection results can be accurately obtained based on the photovoltaic cell fault detection data and photovoltaic cell fault detection data.

Additional aspects and advantages of the disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure.

Drawings

The foregoing and/or additional aspects and advantages of the present disclosure will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

fig. 1 is a flow chart illustrating a method for detecting a failure of a photovoltaic cell according to an embodiment of the present disclosure;

fig. 2 is a flow chart illustrating a method for detecting a failure of a photovoltaic cell according to another embodiment of the present disclosure;

fig. 3 is a flow chart illustrating a method for detecting a failure of a photovoltaic cell according to another embodiment of the present disclosure;

fig. 4 is a schematic diagram of an online fault detection flow for a photovoltaic cell according to the present disclosure;

fig. 5 is a schematic view of a construction flow of a preset feature library according to the present disclosure;

fig. 6 is a schematic structural diagram of a photovoltaic cell failure detection apparatus according to an embodiment of the present disclosure;

fig. 7 illustrates a block diagram of an exemplary computer device suitable for use in implementing embodiments of the present disclosure.

Detailed Description

Embodiments of the present disclosure are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present disclosure and are not to be construed as limiting the present disclosure. On the contrary, the embodiments of the disclosure include all alternatives, modifications, and equivalents as may be included within the spirit and scope of the appended claims.

Fig. 1 is a flow chart illustrating a method for detecting a failure of a photovoltaic cell according to an embodiment of the present disclosure.

It should be noted that, the main execution body of the photovoltaic cell fault detection method in this embodiment is a photovoltaic cell fault detection device, and the device may be implemented in a software and/or hardware manner, and the device may be configured in a computer device, where the computer device may include, but is not limited to, a terminal, a server, and the like, and the terminal may be, for example, a mobile phone, a palm computer, and the like.

As shown in fig. 1, the photovoltaic cell fault detection method includes:

s101: the method comprises the steps of obtaining a real-time open-circuit voltage value, a real-time short-circuit current value, a target voltage value and a target current value of a photovoltaic cell at fault detection time, wherein the real-time open-circuit voltage value and the real-time short-circuit current value form a real-time characteristic array together, and the target voltage value and the target current value are output voltage values and output current values of the photovoltaic cell when the photovoltaic cell is at maximum output power under working conditions corresponding to the real-time characteristic array.

The fault detection time refers to a time point of performing fault detection on the photovoltaic cell based on the photovoltaic cell fault detection method provided by the disclosure.

The real-time open-circuit voltage value and the real-time short-circuit current value refer to the open-circuit voltage value and the short-circuit current value corresponding to the fault detection moment of the photovoltaic cell.

The real-time characteristic array is an array which is formed by the real-time open-circuit voltage value and the real-time short-circuit current value and is used for representing the current working condition characteristics of the photovoltaic cell.

It can be understood that the photovoltaic cell may be applied to different application scenarios, so that the working performance of the photovoltaic cell may be different, and the real-time open-circuit voltage value and the real-time short-circuit current value have higher relevance with the working performance of the photovoltaic cell, so that the real-time feature array can be formed together based on the real-time open-circuit voltage value and the real-time short-circuit current value, thereby providing reliable retrieval basis for subsequently determining the reference voltage value and the reference current value of the photovoltaic cell.

It can be appreciated that in the embodiment of the disclosure, the real-time acquisition of the real-time open-circuit voltage value, the real-time short-circuit current value, the target voltage value and the target current value can be realized based on the pre-configured photovoltaic cell online monitoring module, so that the subsequent steps are triggered, the fault detection is performed on the photovoltaic cell in time, and the real-time performance of the photovoltaic cell fault detection method can be effectively improved.

S102: and determining a reference feature array matched with the real-time feature array from a preset feature library, wherein the preset feature library comprises a plurality of reference feature arrays, and a reference voltage value and a reference current value corresponding to each reference feature array, the reference feature arrays comprise a reference open-circuit voltage value and a reference short-circuit current value, and the reference voltage value and the reference current value are output voltage values and output current values of the photovoltaic cell under the condition that the reference feature array corresponds to the maximum output power.

The preset feature library may be a pre-established database for indicating a mapping relationship between a reference feature array of the photovoltaic cell and a reference voltage value and a reference current value.

The reference characteristic array refers to data composed of a reference open-circuit voltage value and a reference short-circuit current value. The reference open-circuit voltage value and the reference short-circuit current value refer to the open-circuit voltage value and the short-circuit current value measured under each working condition of the photovoltaic cell.

In the embodiment of the disclosure, when determining the reference feature array matched with the real-time feature array from the preset feature library, the reference feature array may be based on a pre-trained machine learning model, or may also be based on a method of combining the figures, which is not limited.

S103: and determining a real-time error variable according to the target voltage value, the target current value and a reference voltage value and a reference current value corresponding to the matched reference feature array in a preset feature library.

It will be appreciated that the error of the photovoltaic cell may be a variable that varies over time, while the real-time error variable refers to the error variable corresponding to the moment of failure detection.

In the embodiment of the disclosure, when determining the real-time error variable according to the target voltage value, the target current value and the reference voltage value and the reference current value corresponding to the matched reference feature array in the preset feature library, the target voltage value, the target current value and the reference voltage value and the reference current value corresponding to the matched reference feature array in the preset feature library may be input into the pre-trained error variable generation model to determine the corresponding error variable, or a third party error variable determining device may be used to determine the real-time error variable according to the target voltage value, the target current value and the reference voltage value and the reference current value corresponding to the matched reference feature array in the preset feature library, which is not limited.

S104: and determining a fault detection result of the photovoltaic cell according to the real-time error variable.

The fault detection result may be used to indicate whether the photovoltaic cell has a fault or may also be used to indicate the type of fault of the photovoltaic cell.

In the embodiment of the disclosure, when determining the fault detection result of the photovoltaic cell according to the real-time error variable, the fault detection result may be based on a pre-configured data relationship table, where the data relationship table includes the real-time error variable and the fault detection result corresponding to the real-time error variable.

In this embodiment, a real-time open-circuit voltage value, a real-time short-circuit current value, a target voltage value and a target current value of a photovoltaic cell at a fault detection time are obtained, wherein the real-time open-circuit voltage value and the real-time short-circuit current value form a real-time feature array together, the target voltage value and the target current value are an output voltage value and an output current value of the photovoltaic cell when the photovoltaic cell is at maximum output power under a working condition corresponding to the real-time feature array, a reference feature array matched with the real-time feature array is determined from a preset feature library, the preset feature library comprises a plurality of reference feature arrays, and a reference voltage value and a reference current value corresponding to each reference feature array, the reference feature array comprises a reference open-circuit voltage value and a reference short-circuit current value, the reference voltage value and the reference current value are output voltage value and the output current value of the photovoltaic cell when the photovoltaic cell is at maximum output power under a working condition corresponding to the reference feature array, a real-time error variable is determined according to the target voltage value, the target current value and the reference voltage value and the reference current value corresponding to the matched reference feature arrays in the preset feature library, and a fault detection result of the photovoltaic cell is determined according to the real-time error variable, so that the fault detection result of the photovoltaic cell can be quickly improved, and the fault detection result of the photovoltaic cell can be obtained, and the reliability of the photovoltaic cell can be obtained.

Fig. 2 is a flow chart illustrating a method for detecting a failure of a photovoltaic cell according to another embodiment of the present disclosure.

As shown in fig. 2, the photovoltaic cell fault detection method includes:

s201: an equivalent circuit model of the photovoltaic cell is established, wherein the equivalent circuit model includes at least one parameter.

The equivalent circuit model may be, for example, a five-parameter model, and parameters corresponding to the model may include: photo-generated current, diode reverse saturation current, series resistance, parallel resistance, and diode management ideal factor.

In the embodiment of the disclosure, when the equivalent circuit model of the photovoltaic cell is established, a reliable analysis object can be provided for the fault analysis process of the photovoltaic cell, so that the fault type of the photovoltaic cell can be quickly determined.

S202: the rated value of each parameter of the photovoltaic cell in the rated working state is obtained, wherein the rated state is used for indicating rated irradiance and rated cell temperature.

The rated operating state may refer to an operating state of the photovoltaic cell during manufacturing. The rated value of the parameter refers to the normal value of each parameter of the photovoltaic cell in the rated working state.

The rated irradiance and the rated battery temperature refer to irradiance and battery temperature indicated by the rated state.

In the embodiment of the disclosure, when the rated value of each parameter of the photovoltaic cell in the rated working state is obtained, reliable reference information can be provided for the reference value of each parameter in the reference working state obtained by subsequent calculation.

S203: a plurality of reference operating conditions are determined, along with a reference irradiance and a reference battery temperature corresponding to each reference operating condition.

The reference working state refers to a working state in which the photovoltaic cell may be in. The reference irradiance and the reference cell temperature refer to irradiance and cell temperature of the photovoltaic cell in the reference operating state.

It can be appreciated that, since the working performance of the photovoltaic cell has a higher degree of correlation with irradiance and cell temperature, when determining a plurality of reference working states, and the reference irradiance and the reference cell temperature corresponding to each reference working state, a reliable execution basis can be provided for subsequent calculation to obtain the reference value of each parameter in the reference working state.

S204: and calculating the reference value of each parameter in the reference working state based on the rated irradiance, the rated battery temperature, the reference irradiance, the reference battery temperature and the rated value of each parameter in the rated working state.

The reference value of the parameter refers to the value of the parameter of the photovoltaic cell in the corresponding reference working state.

In the embodiment of the disclosure, when the reference value of each parameter in the reference working state is calculated based on the rated irradiance, the rated battery temperature, the reference irradiance, the reference battery temperature and the rated value of each parameter in the rated working state, reliable data support can be provided for calculating the reference open-circuit voltage value, the reference short-circuit current value, the reference voltage value and the reference current value corresponding to the reference working state.

S205: and calculating a reference open-circuit voltage value, a reference short-circuit current value, a reference voltage value and a reference current value corresponding to the reference working state based on the reference value of each parameter in the reference working state, wherein the reference open-circuit voltage value and the reference short-circuit current value jointly form a reference characteristic array.

That is, in the embodiment of the present disclosure, after the reference value of each parameter in the reference operating state is obtained, the reference open-circuit voltage value, the reference short-circuit current value, the reference voltage value, and the reference current value corresponding to the reference operating state may be calculated based on the reference value of each parameter in the reference operating state.

S206: and constructing a preset feature library based on the multiple reference feature arrays, and the reference voltage value and the reference current value corresponding to each reference feature array.

That is, in the embodiment of the present disclosure, an equivalent circuit model of a photovoltaic cell may be established, where the equivalent circuit model includes at least one parameter, a rated value of each parameter of the photovoltaic cell in a rated operating state is obtained, where the rated state is used to indicate rated irradiance and rated battery temperature, a plurality of reference operating states, and reference irradiance and reference battery temperature corresponding to each reference operating state, based on the rated irradiance, the rated battery temperature, the reference irradiance, the reference battery temperature, and the rated value of each parameter in the rated operating state, a reference value of each parameter in the reference operating state is calculated, and based on the reference value of each parameter in the reference operating state, a reference open-circuit voltage value, a reference short-circuit current value, a reference voltage value, and a reference current value corresponding to the reference operating state are calculated, where the reference open-circuit voltage value and the reference short-circuit current value jointly form a reference feature array, and a preset feature library is constructed based on the plurality of reference feature arrays, and the reference voltage value and the reference current value corresponding to each reference feature array, thereby reliable reference information can be provided for a fault detection process of the photovoltaic cell, and fault detection efficiency can be effectively improved.

S207: and acquiring a real-time open-circuit voltage value, a real-time short-circuit current value, a target voltage value and a target current value of the photovoltaic cell at the fault detection moment.

The real-time open-circuit voltage value and the real-time short-circuit current value form a real-time characteristic array together, and the target voltage value and the target current value are output voltage values and output current values of the photovoltaic cell when the photovoltaic cell is at maximum output power under the working condition corresponding to the real-time characteristic array.

The description of S207 may be specifically referred to the above embodiments, and will not be repeated here.

S208: and determining a first comparison result of the real-time feature array and each reference feature array in the preset feature library.

The first comparison result refers to a comparison result of the real-time feature array and the reference feature array.

Optionally, in some embodiments, when determining the first comparison result of each reference feature array in the real-time feature array and the preset feature library, the voltage difference between the target voltage value and the reference open-circuit voltage value may be determined, the current difference between the target current value and the reference short-circuit current value may be determined, and the voltage difference and the current difference are combined to be used as the first comparison result, so that difference information of the obtained first comparison result in two dimensions of voltage and current between the real-time feature array and the reference feature array can be effectively improved, and therefore practicality of the obtained first comparison result is effectively improved.

S209: and determining a matched reference feature array from the plurality of reference feature arrays according to the first comparison result.

The matched reference feature array refers to a reference feature array of which the first comparison result indication and the real-time feature array belong to the same feature array.

Optionally, in some embodiments, when determining the matched reference feature array from the multiple reference feature arrays according to the first comparison result, if the first comparison result indicates that the reference feature array meets a preset condition, the corresponding reference feature array is used as a candidate feature array, where the preset condition is used to indicate that a voltage difference value and a current difference value corresponding to the reference feature array are both smaller than a first threshold value, a sum value of the voltage difference value and the current difference value corresponding to each candidate feature array is calculated, and a candidate feature array corresponding to a minimum sum value in the multiple sum values is determined as the matched reference feature array, so that robustness of a process of determining the matched reference feature array can be effectively improved.

The first threshold value refers to a threshold value configured in advance for a voltage difference value and a current difference value between the real-time feature array and the reference feature array, and can be used for judging whether the real-time feature array and the reference feature array belong to the same working condition.

That is, in the embodiment of the present disclosure, after the real-time open-circuit voltage value, the real-time short-circuit current value, the target voltage value, and the target current value of the photovoltaic cell at the fault detection time are obtained, a first comparison result of each reference feature array in the real-time feature array and the preset feature library may be determined, and a matched reference feature array is determined from a plurality of reference feature arrays according to the first comparison result, so that accuracy of the determined matched reference feature array may be effectively improved.

S210: and determining a real-time error variable according to the target voltage value, the target current value and a reference voltage value and a reference current value corresponding to the matched reference feature array in a preset feature library.

S211: and determining a fault detection result of the photovoltaic cell according to the real-time error variable.

The descriptions of S210 and S211 may be specifically referred to the above embodiments, and are not repeated herein.

In this embodiment, by determining the first comparison result of the real-time feature array and each reference feature array in the preset feature library, and determining the matched reference feature array from the multiple reference feature arrays according to the first comparison result, the accuracy of the determined matched reference feature array can be effectively improved. The voltage difference value between the target voltage value and the reference open-circuit voltage value is determined, the current difference value between the target current value and the reference short-circuit current value is determined, and the voltage difference value and the current difference value are combined to be used as a first comparison result, so that the difference information of the obtained first comparison result in two dimensions of voltage and current for the real-time characteristic array and the reference characteristic array can be effectively improved, and the practicability of the obtained first comparison result is effectively improved. If the first comparison result indicates that the reference feature array meets the preset condition, the corresponding reference feature array is used as a candidate feature array, wherein the preset condition is used for indicating that the voltage difference value and the current difference value corresponding to the reference feature array are smaller than a first threshold value, the sum value of the voltage difference value and the current difference value corresponding to each candidate feature array is calculated, and the candidate feature array corresponding to the minimum sum value in the sum values is determined to be used as the matched reference feature array, so that the robustness of the process of determining the matched reference feature array can be effectively improved.

Fig. 3 is a flow chart illustrating a method for detecting a failure of a photovoltaic cell according to another embodiment of the present disclosure.

As shown in fig. 3, the photovoltaic cell fault detection method includes:

s301: and acquiring a real-time open-circuit voltage value, a real-time short-circuit current value, a target voltage value and a target current value of the photovoltaic cell at the fault detection moment.

S302: and determining a reference feature array matched with the real-time feature array from a preset feature library.

The reference characteristic array comprises a reference open-circuit voltage value and a reference short-circuit current value, wherein the reference voltage value and the reference current value correspond to each reference characteristic array, and the reference voltage value and the reference current value are output voltage values and output current values of the photovoltaic cell when the photovoltaic cell is at maximum output power under the working condition corresponding to the reference characteristic array.

The descriptions of S301 and S302 may be specifically referred to the above embodiments, and are not repeated herein.

S303: a first power value of the photovoltaic cell is calculated based on the target voltage value and the target current value.

For example, in the embodiment of the present disclosure, the product of the target voltage value and the target current value may be calculated as the first power value of the photovoltaic cell, where the first power value may refer to the maximum power value of the photovoltaic cell under the real-time working condition.

S304: a second power value of the photovoltaic cell is calculated based on the reference voltage value and the reference current value.

For example, in embodiments of the present disclosure, the product of the reference voltage value and the reference current value may be calculated as a second power value for the photovoltaic cell, where the second power value may refer to a maximum power value of the photovoltaic cell under real-time operating conditions in which no fault exists.

S305: an absolute value of a difference between the first power value and the second power value is calculated.

In the embodiment of the disclosure, when calculating the absolute value of the difference between the first power value and the second power value, the obtained absolute value of the difference can accurately represent the difference information between the real-time maximum power and the reference maximum power of the photovoltaic cell.

S306: the ratio between the absolute value of the difference and the second power value is calculated as a real-time error variable.

That is, in the embodiment of the disclosure, after the reference feature array matched with the real-time feature array is determined from the preset feature library, the first power value of the photovoltaic cell may be calculated based on the target voltage value and the target current value, the second power value of the photovoltaic cell may be calculated based on the reference voltage value and the reference current value, the absolute value of the difference between the first power value and the second power value may be calculated, and the ratio between the absolute value of the difference and the second power value may be calculated as the real-time error variable, so that the obtained real-time error variable may accurately indicate the deviation between the real-time maximum power and the ideal maximum power of the photovoltaic cell, thereby effectively improving the practicality of the real-time error variable in the battery fault detection process.

S307: and determining a power error value, running time information and shielding fault detection requirement information of the photovoltaic cell, wherein the power error value is used for describing the error value generated by the power of the photovoltaic cell in the measuring process.

It can be understood that errors may occur between the measured power value and the actual power value due to the precision of the instrument and equipment in the power measurement process, so that the robustness of the battery fault detection process can be effectively improved when the power error value of the photovoltaic cell is determined in the embodiment of the disclosure. The power error value may take different values based on different measurement methods or measurement tools, for example, may be 2%, which is not limited.

The operation time information may refer to an operation time period from factory delivery to failure detection of the photovoltaic cell.

In the embodiment of the disclosure, due to the fact that the photovoltaic module of the photovoltaic cell has normal attenuation, the photovoltaic cell working performance of different running times is different, and therefore when the running time information of the photovoltaic cell is determined, the reference information of the time dimension can be provided for the subsequent determination of the second threshold.

The requirement information of shielding fault detection refers to requirement information of the photovoltaic cell corresponding to shielding fault detection, and can be used for indicating judgment basis of shielding fault detection, such as shielding area.

In the application scene, the photovoltaic panel of the photovoltaic cell can be blocked by foreign objects (such as leaves) to influence the luminous efficiency of the photovoltaic cell, so that reliable reference information can be provided for subsequent determination of blocking faults based on blocking fault detection requirement information.

S308: a second threshold is determined based on the power error value and the run-time information.

For example, when the photovoltaic module normal decay rate is 0.5%/year and the power error value is 2%, the second threshold for the photovoltaic cell at the first year may be 2.5%.

S309: and determining a third threshold based on the occlusion fault detection requirement information, wherein the second threshold is smaller than the third threshold.

For example, when the occlusion fault detection requirement information indicates that the occlusion area exceeds 20% as an occlusion fault, 20% may be taken as the third threshold.

S310: if the real-time error variable is less than or equal to the second threshold, it is determined that the photovoltaic cell is not malfunctioning.

That is, when the real-time error variable of the photovoltaic cell is less than or equal to the second threshold, it may be determined that the photovoltaic cell is in a normal operating state, and no fault exists.

S311: if the real-time error variable is between the second threshold and the third threshold, it is determined that the photovoltaic cell has an aging fault.

That is, when the real-time error variable of the photovoltaic cell is between the second threshold value and the third threshold value, the photovoltaic cell is determined to be abnormal, and the photovoltaic cell is determined to have an aging fault.

S312: and if the real-time error variable is greater than or equal to a third threshold value, judging that the photovoltaic cell has shadow shielding faults.

That is, when the real-time error variable of the photovoltaic cell is greater than or equal to the third threshold value, it may be determined that the photovoltaic cell has a shadow shielding fault, so that a user may perform fault removal in time.

That is, in the embodiment of the present disclosure, after the real-time error variable is obtained, the power error value, the running time information, and the shielding failure detection requirement information of the photovoltaic cell may be determined, where the power error value is used to describe the error value generated by the power of the photovoltaic cell in the measurement process, the second threshold value is determined based on the power error value and the running time information, the third threshold value is determined based on the shielding failure detection requirement information, where the second threshold value is smaller than the third threshold value, if the real-time error variable is smaller than or equal to the second threshold value, it is determined that the photovoltaic cell has no failure, if the real-time error variable is between the second threshold value and the third threshold value, it is determined that the photovoltaic cell has an aging failure, and if the real-time error variable is greater than or equal to the third threshold value, it is determined that the photovoltaic cell has a shielding failure, thereby, the failure type of the photovoltaic cell can be accurately and rapidly determined based on the real-time error variable, and the practicality of the photovoltaic cell failure detection process can be effectively improved.

In this embodiment, the first power value of the photovoltaic cell is calculated based on the target voltage value and the target current value, the second power value of the photovoltaic cell is calculated based on the reference voltage value and the reference current value, the absolute value of the difference between the first power value and the second power value is calculated, and the ratio between the absolute value of the difference and the second power value is calculated as the real-time error variable, so that the obtained real-time error variable can accurately indicate the deviation between the real-time maximum power of the photovoltaic cell and the ideal maximum power, thereby effectively improving the practicability of the real-time error variable in the battery fault detection process. The power error value is used for describing an error value generated by power of the photovoltaic cell in a measurement process, a second threshold value is determined based on the power error value and the running time information, a third threshold value is determined based on the shielding fault detection requirement information, wherein the second threshold value is smaller than the third threshold value, if a real-time error variable is smaller than or equal to the second threshold value, the photovoltaic cell is judged to have no fault, if the real-time error variable is between the second threshold value and the third threshold value, the photovoltaic cell is judged to have an aging fault, and if the real-time error variable is larger than or equal to the third threshold value, the photovoltaic cell is judged to have a shadow shielding fault, so that the fault type of the photovoltaic cell can be accurately and rapidly determined based on the real-time error variable, and the practicability of the photovoltaic cell fault detection process can be effectively improved.

For example, as shown in fig. 4, fig. 4 is a schematic diagram of an online fault detection flow of a photovoltaic cell according to the present disclosure, where the method includes the following steps:

based on the lambert w function, the established output characteristic equation of the solar cell (photovoltaic cell) under the standard working state is:

V＝-IR _s -IR _p +I _ph R _p -V _t nLambertW(Z)+I ₀ R _p (1)

wherein:

wherein I is the output current of the solar cell, I _ph For generating current by light, I ₀ Is the reverse saturation current of the diode, V is the output voltage, R _s Is a series resistance R _p Is parallel resistor, n is diode management ideal factor, V _t The thermal voltage of the series battery array is calculated as follows:

wherein N is _s The number of solar cells connected in series, k is Boltzmann constant, 1.38X10 ^-23 J/K, T is the working temperature of the solar cell, q is the charge quantity of electrons, 1.6X10 ^-19 C。

The output power of the solar cell is expressed as an output current and an output voltage respectively:

P(I)＝I(-IR _s -IR _p +I _ph R _p -V _t nLambert W(Z)+I ₀ R _p ) (6)

respectively deriving the two formulas to make the derivative equal to 0, and solving to obtain the current and the voltage I at the maximum power point _mp And V _mp ：

The output characteristic equations in the short circuit state and the open circuit state are respectively:

V _oc ＝I _ph R _p -V _t nLambertW(Z)+I ₀ R _p (10)

wherein I is _sc For short-circuit current, V _oc Is an open circuit voltage. Due to I _ph Far greater than I ₀ ，R _p Far greater than R _s Post-approximation I _0,n I _ph,n The calculation formulas of (a) are respectively as follows:

R _s And R is R _p The relation of (2) is:

wherein I is _mp And V is equal to _mp The current and voltage at the maximum power point, respectively.

Series resistance current R under standard working condition _s,n And parallel resistor R _p,n The relationship of (2) may be represented by the following formula:

wherein P is _max,e Is the theoretical maximum power under standard working conditions on the solar cell panel.

R _p Is the minimum value R of (2) _p,min Obtained by the following formula:

the iterative process is as follows: the ideal factor n of the diode takes the value of experience value and initializes R _s,n ＝0、R _p,n ＝R _p,min Solving I through (5) and (6) _0,n 、I _ph,n Carrying out solving of I under the condition by taking the formulas (8) and (9) _mp 、V _mp Multiplying to obtain maximum power P _max . Will P _max Comparing with the theoretical maximum power on the solar cell panel, and finishing iteration if the power is lower than the threshold value; above the threshold value, R is slowly increased _s,n Solving corresponding R through (8) and (6) _p,n 、I _pv,n Solving the corresponding maximum power P by taking the formulas (8) and (9) _max And comparing with the theoretical maximum power on the solar cell panel until the maximum power is lower than the threshold value, and finishing iteration.

(II) by inputting the effective irradiance, the average cell temperature of the cells in the module, and the short-circuit current temperature coefficient mu _Isc Temperature coefficient mu of diode management wanting factor _n Band gap energy epsilon of solar cell material at reference temperature _G And the solar cell I under the standard working condition obtained in the step 1 _ph,n 、I _0,n 、R _s,n 、R _p,n 、n _n Carrying out formulas (17) - (21) to obtain corresponding irradiance and solar energy under temperatureFive parameters of a five parameter model of the battery. Then, the open circuit voltage V under the corresponding irradiance and temperature is obtained by bringing the formulas (8) - (11) _oc,c Short-circuit current I _sc,c I _mp,c 、V _mp,c And forming a theoretical feature library.

R _s ＝R _s,n (17)

n(T)＝n _n +μ _n ·(T-T _n ) (21)

Wherein G is _ref For reference irradiance (1000W/m) ² ) G is the real-time irradiance, G _n Is the reference irradiance.

Monitoring the solar battery in three states of open circuit, short circuit and normal operation through a photovoltaic cell on-line monitoring module, and measuring the solar battery V in real time _oc,m 、I _sc,m 、I _mp,m 、V _mp,m 。

(IV) if V _oc,m And V _mp,m Meanwhile, the value is 0, which indicates that a short circuit fault exists; if I _sc,m And I _mp,m And at the same time 0, indicating an open circuit fault.

And fifthly, forming data pairs by the open-circuit voltage and the short-circuit current in the actual measured data, comparing the open-circuit voltage and the short-circuit current value in each data pair in the theoretical feature library, and determining the data pair with the minimum deviation. The data is closest to the current operating conditions, i.e., temperature and irradiance. In the normal operation state, the measured maximum power point voltage and current should be matched with the maximum power point voltage and current corresponding to the data pair. The variables are defined by assuming that the error values generated by the current and the voltage during the measurement are 1% and 1% respectively

I _e ＝|(I _sc,c -I _sc,m )÷I _sc,c | (22)

V _e ＝|(V _oc,c -V _oc,m )÷V _oc,c | (23)

Wherein I is _sc,c 、V _oc,c The measured short circuit current and open circuit voltage are respectively. The error threshold was set to 2% taking into account the temperature and irradiance differences of the respective curves and the measurement errors. Traversing the feature library to calculate the corresponding I in each feature array _e And V is equal to _e And screening out feature arrays with error thresholds lower than 2%, and indicating that other faults exist if the feature arrays are not present. When a plurality of feature arrays are screened, e is calculated respectively _r ＝I _e +V _e And comparing and selecting e _r The smallest feature array is the current corresponding feature array.

And (six) calculating:

delta and delta are combined _max And comparing, exceeding the threshold value, and judging that aging or shadow shielding faults exist.

Assume that the error value generated by the power during the measurement is 2%. Considering that the normal attenuation rate of the photovoltaic module defined by most photovoltaic module manufacturers is 0.5%/year, a variable parameter based on time is adopted as an aging fault detection threshold, and the calculation formula of the second threshold is as follows:

D _aging ＝(2+0.5t)％ (25)

since the present study only monitored for failures with shadow occlusion of 20% or more, the shadow occlusion failure detection threshold (third threshold) was set to

D _shadow ＝20％

If D<D _aging Indicating that no aging and shadow shielding faults exist; if D _aging <D<D _shadow Indicating the existence of ageing failureThe method comprises the steps of carrying out a first treatment on the surface of the If D>D _shadow Indicating that shadow occlusion faults exist.

For example, based on the above steps, the process of constructing the theoretical feature library (preset feature library) may be as shown in fig. 5, and fig. 5 is a schematic diagram of the construction flow of the preset feature library according to the present disclosure.

Fig. 6 is a schematic structural diagram of a photovoltaic cell failure detection apparatus according to an embodiment of the present disclosure.

As shown in fig. 6, the photovoltaic cell failure detection apparatus 60 includes:

the obtaining module 601 is configured to obtain a real-time open-circuit voltage value, a real-time short-circuit current value, a target voltage value and a target current value of the photovoltaic cell at a fault detection moment, where the real-time open-circuit voltage value and the real-time short-circuit current value together form a real-time feature array, and the target voltage value and the target current value are an output voltage value and an output current value of the photovoltaic cell when the photovoltaic cell is at maximum output power under a working condition corresponding to the real-time feature array;

a first determining module 602, configured to determine a reference feature array matched with the real-time feature array from a preset feature library, where the preset feature library includes a plurality of reference feature arrays, and a reference voltage value and a reference current value corresponding to each reference feature array, where the reference feature arrays include a reference open-circuit voltage value and a reference short-circuit current value, and the reference voltage value and the reference current value are output voltage values and output current values of the photovoltaic cell when the photovoltaic cell is at maximum output power under a working condition corresponding to the reference feature arrays;

A second determining module 603, configured to determine a real-time error variable according to the target voltage value, the target current value, and a reference voltage value and a reference current value corresponding to the matched reference feature array in the preset feature library;

a third determining module 604 is configured to determine a fault detection result of the photovoltaic cell according to the real-time error variable.

It should be noted that the foregoing explanation of the method for detecting a photovoltaic cell fault is also applicable to the device for detecting a photovoltaic cell fault in this embodiment, and will not be repeated here.

Fig. 7 illustrates a block diagram of an exemplary computer device suitable for use in implementing embodiments of the present disclosure. The computer device 12 shown in fig. 7 is merely an example and should not be construed as limiting the functionality and scope of use of the disclosed embodiments.

As shown in fig. 7, the computer device 12 is in the form of a general purpose computing device. Components of computer device 12 may include, but are not limited to: one or more processors or processing units 16, a system memory 28, a bus 18 that connects the various system components, including the system memory 28 and the processing units 16.

Bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include industry Standard architecture (Industry Standard Architecture; hereinafter ISA) bus, micro channel architecture (Micro Channel Architecture; hereinafter MAC) bus, enhanced ISA bus, video electronics standards Association (Video Electronics Standards Association; hereinafter VESA) local bus, and peripheral component interconnect (Peripheral Component Interconnection; hereinafter PCI) bus.

Computer device 12 typically includes a variety of computer system readable media. Such media can be any available media that is accessible by computer device 12 and includes both volatile and nonvolatile media, removable and non-removable media.

Memory 28 may include computer system readable media in the form of volatile memory, such as random access memory (Random Access Memory; hereinafter: RAM) 30 and/or cache memory 32. The computer device 12 may further include other removable/non-removable, volatile/nonvolatile computer system storage media. By way of example only, storage system 34 may be used to read from or write to non-removable, nonvolatile magnetic media (not shown in FIG. 7, commonly referred to as a "hard disk drive").

Although not shown in fig. 7, a magnetic disk drive for reading from and writing to a removable non-volatile magnetic disk (e.g., a "floppy disk"), and an optical disk drive for reading from or writing to a removable non-volatile optical disk (e.g., a compact disk read only memory (Compact Disc Read Only Memory; hereinafter CD-ROM), digital versatile read only optical disk (Digital Video Disc Read Only Memory; hereinafter DVD-ROM), or other optical media) may be provided. In such cases, each drive may be coupled to bus 18 through one or more data medium interfaces. Memory 28 may include at least one program product having a set (e.g., at least one) of program modules configured to carry out the functions of the various embodiments of the disclosure.

A program/utility 40 having a set (at least one) of program modules 42 may be stored in, for example, memory 28, such program modules 42 including, but not limited to, an operating system, one or more application programs, other program modules, and program data, each or some combination of which may include an implementation of a network environment. Program modules 42 generally perform the functions and/or methods in the embodiments described in this disclosure.

The computer device 12 may also communicate with one or more external devices 14 (e.g., keyboard, pointing device, display 24, etc.), one or more devices that enable a person to interact with the computer device 12, and/or any devices (e.g., network card, modem, etc.) that enable the computer device 12 to communicate with one or more other computing devices. Such communication may occur through an input/output (I/O) interface 22. Moreover, the computer device 12 may also communicate with one or more networks such as a local area network (Local Area Network; hereinafter LAN), a wide area network (Wide Area Network; hereinafter WAN) and/or a public network such as the Internet via the network adapter 20. As shown, network adapter 20 communicates with other modules of computer device 12 via bus 18. It should be appreciated that although not shown, other hardware and/or software modules may be used in connection with computer device 12, including, but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, data backup storage systems, and the like.

The processing unit 16 executes various functional applications and data processing by running programs stored in the system memory 28, for example, implementing the photovoltaic cell failure detection method mentioned in the foregoing embodiment.

In order to implement the above-described embodiments, the present disclosure also proposes a non-transitory computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements a photovoltaic cell failure detection method as proposed by the foregoing embodiments of the present disclosure.

To achieve the above-mentioned embodiments, the present disclosure also proposes a computer program product which, when executed by an instruction processor in the computer program product, performs a photovoltaic cell failure detection method as proposed by the foregoing embodiments of the present disclosure.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This disclosure is intended to cover any adaptations, uses, or adaptations of the disclosure following the general principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

It is to be understood that the present disclosure is not limited to the precise arrangements and instrumentalities shown in the drawings, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

It should be noted that in the description of the present disclosure, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Furthermore, in the description of the present disclosure, unless otherwise indicated, the meaning of "a plurality" is two or more.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and further implementations are included within the scope of the preferred embodiment of the present disclosure in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the embodiments of the present disclosure.

It should be understood that portions of the present disclosure may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.

Those of ordinary skill in the art will appreciate that all or a portion of the steps carried out in the method of the above-described embodiments may be implemented by a program to instruct related hardware, where the program may be stored in a computer readable storage medium, and where the program, when executed, includes one or a combination of the steps of the method embodiments.

Furthermore, each functional unit in the embodiments of the present disclosure may be integrated in one processing module, or each unit may exist alone physically, or two or more units may be integrated in one module. The integrated modules may be implemented in hardware or in software functional modules. The integrated modules may also be stored in a computer readable storage medium if implemented in the form of software functional modules and sold or used as a stand-alone product.

The above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, or the like.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present disclosure have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the present disclosure, and that variations, modifications, alternatives, and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the present disclosure.

Claims

1. A method for detecting a failure of a photovoltaic cell, comprising:

2. The method of claim 1, wherein determining a reference feature array from a pre-set feature library that matches the real-time feature array comprises:

determining a first comparison result of the real-time feature array and each reference feature array in the preset feature library;

and determining the matched reference feature array from a plurality of reference feature arrays according to the first comparison result.

3. The method of claim 2, wherein said determining a first comparison of said real-time feature array with each of said reference feature arrays in said library of predetermined features comprises:

determining a voltage difference between the target voltage value and the reference open circuit voltage value;

determining a current difference between the target current value and the reference short circuit current value;

and combining the voltage difference value and the current difference value as the first comparison result.

4. The method of claim 3, wherein said determining said matched reference feature array from a plurality of said reference feature arrays based on said first comparison result comprises:

if the first comparison result indicates that the reference feature array meets a preset condition, the corresponding reference feature array is used as a candidate feature array, wherein the preset condition is used for indicating that the voltage difference value and the current difference value corresponding to the reference feature array are smaller than a first threshold value;

calculating the sum value of the voltage difference value and the current difference value corresponding to each candidate feature array;

and determining the candidate feature array corresponding to the minimum sum value in the sum values as the matched reference feature array.

5. The method of claim 1, wherein the determining a real-time error variable from the target voltage value, the target current value, and the reference voltage value and the reference current value in the preset feature library corresponding to the matched reference feature array comprises:

calculating a first power value of the photovoltaic cell based on the target voltage value and the target current value;

Calculating a second power value for the photovoltaic cell based on the reference voltage value and the reference current value;

calculating an absolute value of a difference between the first power value and the second power value;

a ratio between the absolute value of the difference and the second power value is calculated as the real-time error variable.

6. The method of claim 1, wherein said determining a fault detection result for said photovoltaic cell based on said real-time error variable comprises:

determining a power error value, running time information and shielding fault detection requirement information of the photovoltaic cell, wherein the power error value is used for describing an error value generated by power of the photovoltaic cell in a measurement process;

determining a second threshold based on the power error value and the run-time information;

determining a third threshold based on the occlusion fault detection requirement information, wherein the second threshold is smaller than the third threshold;

if the real-time error variable is less than or equal to the second threshold, determining that the photovoltaic cell is not faulty;

if the real-time error variable is between the second threshold value and the third threshold value, judging that the photovoltaic cell has aging faults;

And if the real-time error variable is greater than or equal to the third threshold value, judging that the photovoltaic cell has shadow shielding faults.

7. The method of any one of claims 1-6, further comprising:

establishing an equivalent circuit model of the photovoltaic cell, wherein the equivalent circuit model comprises at least one parameter;

obtaining rated values of each parameter of the photovoltaic cell in a rated working state, wherein the rated state is used for indicating rated irradiance and rated cell temperature;

determining a plurality of reference working states, and reference irradiance and reference battery temperature corresponding to each reference working state;

calculating a reference value of each parameter in the reference working state based on the rated irradiance, the rated battery temperature, the reference irradiance, the reference battery temperature and the rated value of each parameter in the rated working state;

calculating the reference open-circuit voltage value, the reference short-circuit current value, the reference voltage value and the reference current value corresponding to the reference working state based on the reference value of each parameter in the reference working state, wherein the reference open-circuit voltage value and the reference short-circuit current value jointly form the reference feature array;

And constructing the preset feature library based on a plurality of reference feature arrays, and the reference voltage value and the reference current value corresponding to each reference feature array.

8. A photovoltaic cell failure detection apparatus, comprising:

9. A computer device, comprising:

at least one processor; and

a memory communicatively coupled to the at least one processor; wherein,,

the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-6.

10. A non-transitory computer readable storage medium storing computer instructions, wherein the computer instructions are for causing the computer to perform the method of any one of claims 1-6.