Photovoltaic cell fault monitoring system

Abstract

The invention provides a photovoltaic cell fault monitoring system, and relates to the field of photovoltaic cell monitoring, and the system comprises an operation state collection module which is used for collecting the electrical parameters and temperature parameters of a current photovoltaic cell; the angle acquisition module is used for determining current photovoltaic cell angle information; the ideal voltage simulation module is used for establishing a voltage change rate simulation model and determining the ideal voltage change rate of the current photovoltaic cell; the fault judgment module is used for judging whether the photovoltaic cell is in a fault state or not based on the current electrical parameters of the photovoltaic cell and the ideal voltage change rate; the visualization module is used for visually providing the fault state to an administrator; according to the method, the relation model of the angle, the illumination intensity and the temperature is established, fault monitoring parameters are corrected, and misjudgment of the performance of the photovoltaic cell caused by angle change is avoided; and meanwhile, electrical and temperature parameters and illumination intensity of the photovoltaic cell are comprehensively considered, and a voltage change rate simulation model is established, so that whether the photovoltaic cell is in a fault state or not is accurately judged.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic cell monitoring, and in particular to a photovoltaic cell fault monitoring system. Background Art

[0002] As the global demand for clean energy continues to increase, the photovoltaic industry has developed rapidly. As the core component of the photovoltaic power generation system, the performance and reliability of photovoltaic cells directly affect the power generation efficiency and stability of the entire system. In order to ensure that photovoltaic cells can work properly, real-time monitoring and fault diagnosis have become an important research direction in the field of photovoltaic technology. Early photovoltaic cell monitoring mainly focused on simple electrical parameter measurements, such as voltage and current. With the advancement of technology, the monitoring parameters have gradually become richer, and the impact of environmental factors such as temperature and light intensity on the performance of photovoltaic cells has also begun to attract attention. At the same time, monitoring technology has also developed from a single on-site manual measurement to a remote automated monitoring system, which realizes real-time data collection and transmission of photovoltaic cells through sensor networks and communication technologies.

[0003] In many cases, existing photovoltaic cell monitoring technologies do not fully consider the impact of cell angles on monitoring results. The output power of photovoltaic cells is closely related to light intensity and temperature, which are in turn affected by the cell angle. When the cell angle changes, the actual received light intensity and heat dissipation will change. If the angle factor is not considered, it will lead to misjudgment of battery performance. At the same time, existing monitoring technologies have low accuracy when judging whether photovoltaic cells are faulty. On the one hand, since only some parameters are considered, the operating status of the battery is not comprehensively analyzed, resulting in inaccurate fault judgment. On the other hand, some existing monitoring technologies lack effective methods and models when dealing with complex environmental factors and battery characteristics, resulting in large errors in monitoring results.

[0004] Therefore, there is an urgent need in the art for a photovoltaic cell fault monitoring system to solve the above problems. Summary of the invention

[0005] The present invention provides a photovoltaic cell fault monitoring system, which aims to correct fault monitoring parameters by establishing a relationship model between angle, light intensity and temperature, so as to avoid misjudgment of photovoltaic cell performance due to angle changes; at the same time, the electrical parameters, temperature parameters and light intensity of the photovoltaic cell are comprehensively considered to establish a voltage change rate simulation model, so as to more accurately judge whether the photovoltaic cell is in a fault state.

[0006] The present invention provides a photovoltaic cell fault monitoring system, comprising:

[0007] The operating status acquisition module is set up on the photovoltaic cell and is used to collect the electrical parameters and temperature parameters of the current photovoltaic cell;

[0008] Angle acquisition module, which is used to obtain the current sun position and determine the current photovoltaic cell angle information in combination with the inclination and deflection of the photovoltaic cell;

[0009] An ideal voltage simulation module, which is connected to the operation status acquisition module and the angle acquisition module, and is used to establish a voltage change rate simulation model in combination with the electrical parameters, temperature parameters and angle information of the current photovoltaic cell, and determine the ideal voltage change rate of the current photovoltaic cell;

[0010] A fault judgment module, which is connected to the operation status acquisition module and the ideal voltage simulation module, and judges whether the photovoltaic cell is in a fault state based on the electrical parameters of the current photovoltaic cell and the ideal voltage change rate;

[0011] A visualization module is connected to the fault judgment module and is used to provide the administrator with a visualized fault status.

[0012] According to a photovoltaic cell fault monitoring system provided by the present invention, the operation status acquisition module comprises:

[0013] A cycle setting unit, which is used to pre-set a collection cycle and control the electrical parameter acquisition unit to collect data according to the preset cycle;

[0014] The electrical parameter acquisition unit is used to obtain the current output voltage V of the photovoltaic cell. t , and the difference between the current output voltage and the output voltage of the previous cycle, that is, the voltage change value ΔV t ;

[0015] The temperature parameter acquisition unit is used to obtain the current average surface temperature T of the photovoltaic cell. t .

[0016] According to a photovoltaic cell fault monitoring system provided by the present invention, the operation status acquisition module further includes:

[0017] A basic database, which is used to store basic parameters and theoretical parameters of photovoltaic cells; the basic parameters include photovoltaic cell area A, reflectivity ρ, specific heat capacity C, and mass M;

[0018] The theoretical parameters include the initial temperature T0, initial light intensity I0 and initial voltage change rate of the photovoltaic cell under vertical illumination conditions.

[0019] According to a photovoltaic cell fault monitoring system provided by the present invention, the angle acquisition module comprises:

[0020] The cell angle acquisition unit is used to obtain the tilt angle β of the current photovoltaic cell. r and the direction angle γ r ;

[0021] A current sun angle acquisition unit, which is used to acquire the current sun zenith angle E and sun direction angle γ;

[0022] An angle determination unit, which is connected to the battery angle acquisition unit and the current sun angle acquisition unit, based on the formula cosθ=cosβ r cosE+sinβ r sinE*cos(γ r -γ) determines the cosine cosθ of the current photovoltaic cell angle, and then determines the current photovoltaic cell angle information θ.

[0023] According to a photovoltaic cell fault monitoring system provided by the present invention, the ideal voltage simulation module includes:

[0024] The ideal illumination intensity simulation unit is connected to the basic database and the angle determination unit, and establishes and trains an illumination intensity simulation model based on the current photovoltaic cell angle information θ and the initial illumination intensity I0 to determine the current ideal illumination intensity data I θ ;

[0025] The ideal temperature simulation unit is connected to the ideal light intensity simulation unit, the basic database and the angle determination unit, and establishes and trains a temperature simulation model based on the current photovoltaic cell angle information θ, the initial temperature T0 and the basic parameters of the photovoltaic cell to determine the current ideal temperature data T θ ;

[0026] The ideal voltage change rate simulation unit is connected to the ideal light intensity simulation unit and the ideal temperature simulation unit, and based on the current ideal light intensity data I θ 、Current ideal temperature data T θ , Initial voltage change rate Establish and train the voltage change rate simulation model to determine the current ideal voltage change rate

[0027] A training unit is connected to the ideal light intensity simulation unit, the ideal temperature simulation unit and the ideal voltage change rate simulation unit, and is used to train each model according to historical data.

[0028] According to a photovoltaic cell fault monitoring system provided by the present invention, the light intensity simulation model is:

[0029]

[0030] Among them, Iθ is the current ideal light intensity data, θ is the current photovoltaic cell angle information, I0 is the initial light intensity; n is the sensitivity coefficient, which is used to reflect the sensitivity of the photovoltaic cell to the change of the light incident angle and the optical properties of the photovoltaic panel itself. The value of n will affect the rate at which the light intensity decreases as the incident angle changes; k is the nonlinear coefficient, which is used to adjust the degree of nonlinear change caused by the incident angle and the photovoltaic cell material and structure factors; the sensitivity coefficient n and the nonlinear coefficient k are both determined by the training unit.

[0031] According to a photovoltaic cell fault monitoring system provided by the present invention, the temperature simulation model is:

[0032]

[0033] Among them, T θ is the current ideal temperature data, T0 is the initial temperature, A is the photovoltaic cell area, ρ is the photovoltaic cell reflectivity, which indicates the ratio of reflected solar radiation power to incident power, C is the photovoltaic cell specific heat capacity, which indicates the heat required to raise the unit mass of the panel by one degree Celsius, and M is the mass of the photovoltaic cell; S is the solar constant, which indicates the solar radiation power received per unit area perpendicular to the direction of sunlight outside the earth's atmosphere; I θ is the current ideal light intensity data.

[0034] According to a photovoltaic cell fault monitoring system provided by the present invention, the voltage change rate simulation model is:

[0035]

[0036] in, is the ideal voltage change rate, is the initial voltage change rate, and They are the current ideal light intensity data I θ And the current ideal temperature data T θ The derivative of ; d is the electrical characteristic coefficient, which is used to combine the electrical characteristics of the photovoltaic cell to reflect the influence of the rate of change of light intensity with angle on the rate of change of photovoltaic cell voltage; e is the temperature characteristic coefficient, which is used to combine the temperature characteristics of the photovoltaic cell to reflect the influence of the rate of change of temperature with angle on the rate of change of photovoltaic cell voltage; the electrical characteristic coefficient d and the temperature characteristic coefficient e are both determined by the training unit.

[0037] According to a photovoltaic cell fault monitoring system provided by the present invention, the fault judgment module comprises:

[0038] A difference calculation unit, which is connected to the ideal voltage change rate simulation unit and the electrical parameter acquisition unit, and is used to calculate the voltage change rate difference

[0039] A threshold setting unit, which is used to set the difference threshold ΔV x0 , which is pre-set based on the voltage change rate standard of the photovoltaic cell;

[0040] A result generating unit connected to the difference calculating unit and the threshold setting unit for comparing the voltage change rate difference ΔV x and difference threshold ΔV x0 ; When ΔV x >ΔV x0 When the photovoltaic cell is in a fault state, it is judged that the photovoltaic cell is in a fault state. x ≤ΔV x0 It can be judged that the current photovoltaic cell is in normal state.

[0041] Compared with the prior art, the beneficial effects of this application are:

[0042] This application establishes a relationship model between angle, light intensity and temperature by fully considering the impact of battery angle on monitoring results; determines the battery angle by obtaining information such as the tilt angle and direction angle of the battery's tilt surface and the sun's zenith angle and direction angle; simulates and calculates light intensity and temperature based on this angle information, taking into account the differences in light and heat dissipation caused by angle changes, avoiding misjudgment caused by angle factors, and improving the fit between monitoring results and actual conditions;

[0043] This application comprehensively considers multiple parameters to more comprehensively understand the working status of photovoltaic cells, avoid misjudgment due to the limitations of a single parameter, improve the accuracy of fault monitoring, and more keenly capture potential fault hazards of batteries, reducing economic losses and maintenance costs caused by misjudgment;

[0044] This application analyzes the electrical and temperature characteristics of the battery from multiple physical levels, uses these coefficients to accurately adjust the simulation results of the model, simulates the ideal voltage change rate of the photovoltaic cell under different conditions, and accurately determines whether the photovoltaic cell is faulty by comparing the difference between the actual voltage change rate and the ideal voltage change rate and comparing it with the set threshold.

[0045] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0046] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0048] Figure 1 It is a structural schematic diagram of a photovoltaic cell fault monitoring system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0050] Embodiment 1:

[0051] The present invention provides a photovoltaic cell fault monitoring system. Figure 1 ,include:

[0052] The operating status acquisition module is set up on the photovoltaic cell and is used to collect the electrical parameters and temperature parameters of the current photovoltaic cell;

[0053] Angle acquisition module, which is used to obtain the current sun position and determine the current photovoltaic cell angle information in combination with the inclination and deflection of the photovoltaic cell;

[0054] The ideal voltage simulation module is connected to the operation status acquisition module and the angle acquisition module, and is used to establish a voltage change rate simulation model in combination with the electrical parameters, temperature parameters and angle information of the current photovoltaic cell to determine the ideal voltage change rate of the current photovoltaic cell;

[0055] A fault judgment module is connected to the operation status acquisition module and the ideal voltage simulation module, and judges whether the photovoltaic cell is in a fault state based on the electrical parameters of the current photovoltaic cell and the ideal voltage change rate;

[0056] The visualization module is connected to the fault judgment module and is used to provide the administrator with a visualization of the fault status.

[0057] The principle of the above embodiment is: the operation status acquisition module collects electrical parameters (such as current, voltage, etc.) and temperature parameters by being set up on the photovoltaic cell, and these parameters reflect the current working status of the photovoltaic cell; the angle acquisition module obtains the current sun position and determines the angle information in combination with the inclination and deflection of the photovoltaic cell, because the output of the photovoltaic cell will be affected by the sun angle; the ideal voltage simulation module receives the electrical parameters and temperature parameters of the operation status acquisition module and the angle information of the angle acquisition module, and establishes a voltage change rate simulation model; the model can determine the voltage change rate of the photovoltaic cell under ideal conditions based on the current environmental conditions and the characteristics of the photovoltaic cell; the fault judgment module compares the actual electrical parameters collected by the operation status acquisition module with the ideal voltage change rate determined by the ideal voltage simulation module. If the actual electrical parameters deviate greatly from the ideal situation, it is judged that the photovoltaic cell is in a fault state; finally, the visualization module provides the fault state to the administrator in an intuitive manner so that the administrator can take timely measures to repair or adjust it.

[0058] The beneficial effects of the above embodiments are: it can collect the electrical parameters, temperature parameters and angle information of photovoltaic cells in real time and detect faults in time; by establishing a voltage change rate simulation model and combining various information for fault judgment, the accuracy of judgment is improved; the fault status is provided to the administrator in a visual manner, so that the administrator can quickly understand the situation and take corresponding measures; it is helpful to detect and solve photovoltaic cell failures in time and improve the power generation efficiency and stability of the photovoltaic system; it takes into account factors such as the position of the sun and the angle of the photovoltaic cell, and is suitable for different installation environments and operating conditions.

[0059] In order to further optimize the above embodiment, the operation status acquisition module includes:

[0060] A cycle setting unit, which is used to pre-set a collection cycle and control the electrical parameter acquisition unit to collect data according to the preset cycle;

[0061] The electrical parameter acquisition unit is used to obtain the current output voltage V of the photovoltaic cell. t , and the difference between the current output voltage and the output voltage of the previous cycle, that is, the voltage change value ΔV t ;

[0062] The temperature parameter acquisition unit is used to obtain the current average surface temperature T of the photovoltaic cell. t .

[0063] It should be noted that the cycle setting unit can be implemented by a timer module inside a microcontroller (such as a common single-chip microcomputer); the time interval of the acquisition cycle is determined by programming the timer; the voltage measurement in the electrical parameter acquisition unit can use a voltage sensor or a voltage transformer; the voltage sensor has the advantages of high precision and good linearity, and can directly convert the voltage signal into an electrical signal that can be processed by the microcontroller (such as an analog signal with a voltage range of 0-5V); the voltage transformer is suitable for high voltage measurement scenarios, which can convert high voltage into low voltage in proportion, and then measure it; in order to obtain the voltage change value, a differential amplifier circuit can be used to amplify the difference signal between the current output voltage and the output voltage of the previous cycle; the differential amplifier can effectively suppress common-mode interference and improve the measurement accuracy of the signal; temperature measurement can use thermocouples, thermistors or integrated temperature sensors; for thermocouples and thermistors, corresponding signal conditioning circuits are required to convert temperature signals into electrical signals that can be processed by the microcontroller; the signal conditioning circuit usually includes circuit elements such as amplifiers and filters for amplifying and filtering temperature signals.

[0064] In order to further optimize the above embodiment, the running status acquisition module also includes:

[0065] Basic database, which is used to store basic parameters and theoretical parameters of photovoltaic cells; basic parameters include photovoltaic cell area A, reflectivity ρ, specific heat capacity C, and mass M;

[0066] Theoretical parameters include the initial temperature T0, initial light intensity I0 and initial voltage change rate of the photovoltaic cell under vertical illumination conditions.

[0067] It should be noted that the initial temperature T0 can be determined by placing the photovoltaic cell under vertical lighting conditions in a laboratory environment and measuring its temperature using a temperature sensor; during the measurement process, it is necessary to ensure that the conditions such as light intensity and ambient temperature are relatively stable to obtain an accurate initial temperature value; the initial light intensity I0 can be measured using a light intensity sensor under vertical lighting conditions; similarly, the stability of the measurement environment must be ensured to ensure the accuracy of the measurement results; the initial voltage change rate The initial voltage change rate can be determined by continuously measuring the voltage of the photovoltaic cell under vertical illumination conditions, and then calculating the ratio of the voltage change value to the voltage value between adjacent measurement time points; for example, if the voltage V1 is measured at time t1 and the voltage V2 is measured at time t2, the initial voltage change rate can be determined by the formula to calculate.

[0068] In order to further optimize the above embodiment, the angle acquisition module includes:

[0069] The cell angle acquisition unit is used to obtain the tilt angle β of the current photovoltaic cell. r and the direction angle γ r ;

[0070] A current sun angle acquisition unit, which is used to acquire the current sun zenith angle E and sun direction angle γ;

[0071] Angle determination unit, which is connected to the battery angle acquisition unit and the current sun angle acquisition unit, based on the formula cosθ=cosβ r cosE+sinβ r sinE*cos(γ r -γ) determines the cosine cosθ of the current photovoltaic cell angle, and then determines the current photovoltaic cell angle information θ.

[0072] It should be noted that, from the perspective of vectors, the direction of sunlight and the normal direction of the photovoltaic cell are regarded as two vectors, and the cosine value of their angle, that is, the cosine value of the photovoltaic cell angle, is obtained according to the definition of vector dot product.

[0073] To calculate the vector dot product, it is necessary to determine the coordinates of the two vectors in the horizontal coordinate system. The direction vector of the sun's rays can be determined by the solar zenith angle and the solar direction angle, and the normal direction vector of the photovoltaic cell is determined by the inclination angle and direction angle of the photovoltaic cell's tilt surface.

[0074] By substituting the two vector coordinates into the vector dot product formula and simplifying it using the sum and difference formula of trigonometric functions, we finally get an expression for the relationship between the cosine value of the photovoltaic cell angle and the inclination angle of the tilt surface, the solar zenith angle, the direction angle and the solar direction angle, so that the photovoltaic cell angle can be determined based on these angle information.

[0075] In order to further optimize the above embodiment, the ideal voltage simulation module includes:

[0076] The ideal light intensity simulation unit is connected to the basic database and the angle determination unit, and establishes and trains the light intensity simulation model based on the current photovoltaic cell angle information θ and the initial light intensity I0 to determine the current ideal light intensity data I θ ;

[0077] The ideal temperature simulation unit is connected to the ideal light intensity simulation unit, the basic database and the angle determination unit, and establishes and trains a temperature simulation model based on the current photovoltaic cell angle information θ, the initial temperature T0 and the basic parameters of the photovoltaic cell to determine the current ideal temperature data T θ ;

[0078] The ideal voltage change rate simulation unit is connected to the ideal light intensity simulation unit and the ideal temperature simulation unit, and based on the current ideal light intensity data I θ、Current ideal temperature data T θ , Initial voltage change rate Establish and train a voltage change rate simulation model to determine the current ideal voltage change rate

[0079] A training unit, which is connected to the ideal light intensity simulation unit, the ideal temperature simulation unit, and the ideal voltage change rate simulation unit, and is used to train each model according to historical data;

[0080] The light intensity simulation model is:

[0081]

[0082] Among them, I θ is the current ideal light intensity data, θ is the current photovoltaic cell angle information, and I0 is the initial light intensity; n is the sensitivity coefficient, which is used to reflect the sensitivity of the photovoltaic cell to the change of the light incident angle and the optical characteristics of the photovoltaic panel itself. The value of n will affect the rate at which the light intensity decreases as the incident angle changes; k is the nonlinear coefficient, which is used to adjust the degree of nonlinear changes caused by the incident angle and the photovoltaic cell material and structure factors; the sensitivity coefficient n and the nonlinear coefficient k are both determined by the training unit;

[0083] The temperature simulation model is:

[0084]

[0085] Among them, T θ is the current ideal temperature data, T0 is the initial temperature, A is the photovoltaic cell area, ρ is the photovoltaic cell reflectivity, which indicates the ratio of reflected solar radiation power to incident power, C is the photovoltaic cell specific heat capacity, which indicates the heat required to raise the unit mass of the panel by one degree Celsius, and M is the mass of the photovoltaic cell; S is the solar constant, which indicates the solar radiation power received per unit area perpendicular to the direction of sunlight outside the earth's atmosphere; I θ is the current ideal light intensity data.

[0086] The voltage change rate simulation model is;

[0087]

[0088] in, is the ideal voltage change rate, is the initial voltage change rate, and They are the current ideal light intensity data I θ And the current ideal temperature data T θThe derivative of ; d is the electrical characteristic coefficient, which is used to combine the electrical characteristics of the photovoltaic cell to reflect the influence of the rate of change of light intensity with angle on the rate of change of photovoltaic cell voltage; e is the temperature characteristic coefficient, which is used to combine the temperature characteristics of the photovoltaic cell to reflect the influence of the rate of change of temperature with angle on the rate of change of photovoltaic cell voltage; the electrical characteristic coefficient d and the temperature characteristic coefficient e are both determined by the training unit.

[0089] It should be noted that the light intensity simulation model is used to simulate the current ideal light intensity data based on the photovoltaic cell angle information and the initial light intensity. Considering the sensitivity of photovoltaic cells to changes in light incident angle and their own optical properties, the sensitivity coefficient n is introduced. The n value affects the rate at which light intensity decreases as the incident angle changes, and reflects the comprehensive effect of the solar panel on optical processes such as light absorption and reflection at different incident angles. At the same time, in order to consider the degree of nonlinear changes caused by the incident angle and photovoltaic cell materials and structural factors, a nonlinear coefficient is set. It can adjust the model to better adapt to the complex nonlinear relationship between light intensity and angle changes in actual situations.

[0090] The temperature simulation model determines the current ideal temperature data based on the photovoltaic cell angle information, initial temperature and basic parameters.

[0091] From the perspective of heat absorption and transfer, the solar radiation power absorbed by photovoltaic cells is related to the light intensity, and the reflectivity affects the absorption ratio. Area, specific heat capacity and mass are basic parameters related to battery thermal capacity and heat transfer. The solar constant represents the solar radiation power received per unit area outside the Earth's atmosphere, which is a benchmark value. Based on these factors, a formula is established to simulate the change of temperature with angle. When the angle changes, the light intensity changes, which in turn affects the heat absorption. Combined with the thermal characteristics of the battery itself (determined by area, specific heat capacity and mass), the ideal temperature at different angles can be simulated.

[0092] The voltage change rate simulation model is designed to simulate the current ideal voltage change rate according to the current ideal light intensity data, the ideal temperature data and the initial voltage change rate.

[0093] The changes in light intensity and temperature with angle will affect the voltage of photovoltaic cells. The electrical characteristic coefficient combines the electrical characteristics of photovoltaic cells to reflect the degree of influence of the rate of change of light intensity with angle on the rate of change of voltage. The temperature characteristic coefficient combines the temperature characteristics of the battery to reflect the influence of the rate of change of temperature with angle on the rate of change of voltage.

[0094] By calculating the derivatives of the current ideal light intensity data and the ideal temperature data, we can obtain information about their rate of change with angle. Taking these factors into account in the formula, and then using the training unit to determine the values ​​of the electrical characteristic coefficient and the temperature characteristic coefficient, the model can accurately simulate the ideal voltage change rate under different conditions.

[0095] Among them, the process of training and determining the sensitivity coefficient n and the nonlinear coefficient k is as follows: collect a large amount of actual measurement data of the light intensity of photovoltaic cells at different angles, and record the corresponding angle information and relevant parameters of the cell itself (such as materials, structures, etc. that may affect the optical properties). These data will be used as training samples; set the objective function, the goal is to minimize the error between the simulated light intensity value and the actual measured value. Here, the mean square error (MSE) can be used as an indicator to measure the error; use an optimization algorithm (such as the gradient descent algorithm) to adjust the values ​​of the sensitivity coefficient n and the nonlinear coefficient k to minimize the objective function. In each iteration, the simulated light intensity is calculated based on the current coefficient value, and then the error is calculated and the coefficient value is updated based on the error. This process is repeated until the error reaches an acceptable level or the stopping condition is met (such as reaching the maximum number of iterations)

[0096] The training process for the electrical characteristic coefficient d and the temperature characteristic coefficient e can be:

[0097] Data preparation: A large amount of actual measurement data of the voltage change rate of photovoltaic cells under different angles, light intensities and temperatures, as well as the corresponding angle, light intensity and temperature information, are also collected. These data constitute the training data set.

[0098] Goal setting: The goal is to minimize the error between the simulated voltage change rate and the actual measured voltage change rate. A similar mean square error is used as the error measure;

[0099] Output: Use optimization algorithms (such as stochastic gradient descent algorithm) to adjust the electrical characteristic coefficient d and temperature characteristic coefficient e. Each iteration calculates the analog voltage change rate according to the current coefficient value, then calculates the error and updates the coefficient value based on the error. Continue iterating until the error meets the requirements or the stop condition is met (such as the specified number of iterations is used up).

[0100] In order to further optimize the above embodiment, the fault judgment module includes:

[0101] The difference calculation unit is connected to the ideal voltage change rate simulation unit and the electrical parameter acquisition unit to calculate the voltage change rate difference.

[0102] A threshold setting unit, which is used to set the difference threshold ΔV x0 , which is pre-set based on the voltage change rate standard of the photovoltaic cell;

[0103] The result generating unit is connected to the difference calculating unit and the threshold setting unit to compare the voltage change rate difference ΔV x and the difference threshold ΔV x0 ; When ΔV x >ΔV x0 When the photovoltaic cell is in a fault state, it is judged that the photovoltaic cell is in a fault state. x ≤ΔV x0 It can be judged that the current photovoltaic cell is in normal state.

[0104] It should be noted that the setting of the difference threshold needs to be based on the voltage change rate standard of the photovoltaic cell; this standard is usually obtained by statistically analyzing the voltage change rate of a large number of normally working photovoltaic cells under different environmental conditions (such as different light intensities, temperatures, angles, etc.); in practical applications, it is also necessary to make appropriate adjustments based on the specific photovoltaic cell system characteristics and usage environment; for example, if the environmental conditions of the photovoltaic cell are relatively harsh (such as large temperature changes, unstable light, etc.), it may be necessary to appropriately increase the difference threshold to avoid misjudgment; on the contrary, if the environmental conditions are relatively stable and the accuracy requirements for fault detection are high, the difference threshold can be appropriately reduced.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A photovoltaic cell fault monitoring system, characterized in that: include: The operating status acquisition module is set up on the photovoltaic cell and is used to collect the electrical parameters and temperature parameters of the current photovoltaic cell; Angle acquisition module, which is used to obtain the current sun position and determine the current photovoltaic cell angle information in combination with the inclination and deflection of the photovoltaic cell; An ideal voltage simulation module, which is connected to the operation status acquisition module and the angle acquisition module, and is used to establish a voltage change rate simulation model in combination with the electrical parameters, temperature parameters and angle information of the current photovoltaic cell, and determine the ideal voltage change rate of the current photovoltaic cell; A fault judgment module, which is connected to the operation status acquisition module and the ideal voltage simulation module, and judges whether the photovoltaic cell is in a fault state based on the electrical parameters of the current photovoltaic cell and the ideal voltage change rate; The visualization module is connected to the fault judgment module and is used to provide the administrator with a visualized fault status.

2. A photovoltaic cell fault monitoring system according to claim 1, characterized in that: The operating status acquisition module includes: A cycle setting unit, which is used to pre-set a collection cycle and control the electrical parameter acquisition unit to collect data according to the preset cycle; The electrical parameter acquisition unit is used to obtain the current output voltage V of the photovoltaic cell. t , and the difference between the current output voltage and the output voltage of the previous cycle, that is, the voltage change value ΔV t ; The temperature parameter acquisition unit is used to obtain the current average surface temperature T of the photovoltaic cell. t .

3. A photovoltaic cell fault monitoring system according to claim 2, characterized in that: The running status acquisition module also includes: A basic database, which is used to store basic parameters and theoretical parameters of photovoltaic cells; the basic parameters include photovoltaic cell area A, reflectivity ρ, specific heat capacity C, and mass M; The theoretical parameters include the initial temperature T0, initial light intensity I0 and initial voltage change rate of the photovoltaic cell under vertical illumination conditions.

4. A photovoltaic cell fault monitoring system according to claim 3, characterized in that: The angle acquisition module comprises: The cell angle acquisition unit is used to obtain the tilt angle β of the current photovoltaic cell. r and the direction angle γ r ; A current sun angle acquisition unit, which is used to acquire the current sun zenith angle E and sun direction angle γ; An angle determination unit, which is connected to the battery angle acquisition unit and the current sun angle acquisition unit, based on the formula cosθ=cosβ r cosE+sinβ r sinE*cos(γ r -γ) determines the cosine cosθ of the current photovoltaic cell angle, and then determines the current photovoltaic cell angle information θ.

5. A photovoltaic cell fault monitoring system according to claim 4, characterized in that: The ideal voltage simulation module comprises: The ideal light intensity simulation unit is connected to the basic database and the angle determination unit, and establishes and trains a light intensity simulation model based on the current photovoltaic cell angle information θ and the initial light intensity I0 to determine the current ideal light intensity data I θ ; The ideal temperature simulation unit is connected to the ideal light intensity simulation unit, the basic database and the angle determination unit, and establishes and trains a temperature simulation model based on the current photovoltaic cell angle information θ, the initial temperature T0 and the photovoltaic cell basic parameters to determine the current ideal temperature data T θ ; The ideal voltage change rate simulation unit is connected to the ideal light intensity simulation unit and the ideal temperature simulation unit, and based on the current ideal light intensity data I θ 、Current ideal temperature data T θ , Initial voltage change rate Establish and train a voltage change rate simulation model to determine the current ideal voltage change rate A training unit is connected to the ideal light intensity simulation unit, the ideal temperature simulation unit and the ideal voltage change rate simulation unit, and is used to train each model according to historical data.

6. A photovoltaic cell fault monitoring system according to claim 5, characterized in that: The light intensity simulation model is: Among them, I θ is the current ideal light intensity data, θ is the current photovoltaic cell angle information, I0 is the initial light intensity; n is the sensitivity coefficient, which is used to reflect the sensitivity of the photovoltaic cell to the change of the light incident angle and the optical properties of the photovoltaic panel itself. The value of n will affect the rate at which the light intensity decreases as the incident angle changes; k is the nonlinear coefficient, which is used to adjust the degree of nonlinear change caused by the incident angle and the photovoltaic cell material and structure factors; the sensitivity coefficient n and the nonlinear coefficient k are both determined by the training unit.

7. A photovoltaic cell fault monitoring system according to claim 6, characterized in that: The temperature simulation model is: Among them, T θ is the current ideal temperature data, T0 is the initial temperature, A is the photovoltaic cell area, ρ is the photovoltaic cell reflectivity, which indicates the ratio of reflected solar radiation power to incident power, C is the photovoltaic cell specific heat capacity, which indicates the heat required to raise the unit mass of the panel by one degree Celsius, and M is the mass of the photovoltaic cell; S is the solar constant, which indicates the solar radiation power received per unit area perpendicular to the direction of sunlight outside the earth's atmosphere; I θ is the current ideal light intensity data.

8. A photovoltaic cell fault monitoring system according to claim 7, characterized in that: The voltage change rate simulation model is: in, is the ideal voltage change rate, is the initial voltage change rate, and They are the current ideal light intensity data I θ And the current ideal temperature data T θ The derivative of ; d is the electrical characteristic coefficient, which is used to combine the electrical characteristics of the photovoltaic cell to reflect the influence of the rate of change of light intensity with angle on the rate of change of photovoltaic cell voltage; e is the temperature characteristic coefficient, which is used to combine the temperature characteristics of the photovoltaic cell to reflect the influence of the rate of change of temperature with angle on the rate of change of photovoltaic cell voltage; the electrical characteristic coefficient d and the temperature characteristic coefficient e are both determined by the training unit.

9. A photovoltaic cell fault monitoring system according to claim 8, characterized in that: The fault judgment module comprises: A difference calculation unit, which is connected to the ideal voltage change rate simulation unit and the electrical parameter acquisition unit, and is used to calculate the voltage change rate difference A threshold setting unit, which is used to set the difference threshold ΔV x0 , which is pre-set based on the voltage change rate standard of the photovoltaic cell; A result generating unit connected to the difference calculating unit and the threshold setting unit for comparing the voltage change rate difference ΔV x and difference threshold ΔV x0 ; When ΔV x >ΔV x0 When the photovoltaic cell is in a fault state, it is judged that the photovoltaic cell is in a fault state. x ≤ΔV x0 It can be judged that the current photovoltaic cell is in normal state.

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