Energy efficiency evaluation method for large-span flexible high support and double-sided assembly photovoltaic system

Abstract

The invention relates to an energy efficiency evaluation method for a large-span flexible high support and a double-sided assembly photovoltaic system, and the method comprises the steps: obtaining an azimuth angle and an elevating angle of a target, and determining a tracking angle of the double-sided assembly photovoltaic system according to the azimuth angle and the elevating angle of the target; the front irradiation dose and the back irradiation dose of the double-sided assembly photovoltaic system are calculated at different tracking angles in combination with different north-south distances and support heights, the total irradiation dose of the multiple double-sided assembly photovoltaic systems is obtained, and the tracking angle, the north-south distance and the support height corresponding to the maximum total irradiation dose serve as optimal target tracking results; and obtaining a dynamic shadow formed by the environment temperature, the environment diffuse reflection, the dust raising degree and the north-south interval of the double-sided assembly photovoltaic system, performing energy efficiency evaluation based on the dynamic shadow formed by the environment temperature, the environment diffuse reflection, the dust raising degree and the north-south interval of the double-sided assembly photovoltaic system, and obtaining an energy efficiency evaluation result of the double-sided assembly photovoltaic system. The accuracy of economic and technical feasibility research can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation, and in particular to an energy efficiency evaluation method for a large-span flexible high bracket and a double-sided component photovoltaic system. Background Art

[0002] The current photovoltaic system generally uses low-profile fixed brackets and single-sided photovoltaic modules. The system energy efficiency evaluation method is relatively simple and does not take into account the back gain contribution of the double-sided photovoltaic modules, the fact that high brackets are conducive to reducing module temperature under wind speed, the fact that they are conducive to keeping the photovoltaic modules clean, and the fact that a larger north-south spacing is conducive to reducing shadows. Therefore, the calculated system energy efficiency often deviates greatly from the measured parameters, which is not conducive to ensuring the accuracy and rationality of the economic and technical feasibility study in the project development stage. Summary of the invention

[0003] In order to solve the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an energy efficiency evaluation method for a large-span flexible high bracket and a double-sided component photovoltaic system, fully considering more practical factors and improving the accuracy and rationality of economic and technical feasibility studies.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] Energy efficiency evaluation method for photovoltaic system with large-span flexible high bracket and bifacial modules, including:

[0006] Acquiring the azimuth and altitude of the target, and determining the tracking angle of the bifacial module photovoltaic system according to the azimuth and altitude of the target;

[0007] Calculate the front and back irradiance of the bifacial photovoltaic system at different tracking angles combined with different north-south spacings and bracket heights, obtain the total irradiance of multiple bifacial photovoltaic systems, and take the tracking angle, north-south spacing and bracket height corresponding to the maximum total irradiance as the best target tracking result;

[0008] The ambient temperature, ambient diffuse reflection, dust level and dynamic shadows formed by the north-south distance of the bifacial component photovoltaic system are obtained, and energy efficiency evaluation is performed based on the ambient temperature, ambient diffuse reflection, dust level and dynamic shadows formed by the north-south distance of the bifacial component photovoltaic system to obtain the energy efficiency evaluation result of the bifacial component photovoltaic system.

[0009] Optionally, the formula for determining the tracking angle of the bifacial photovoltaic system is:

[0010]

[0011] Among them, θ is the reference tracking angle of the bifacial photovoltaic module, A is the solar altitude angle, and B is the solar azimuth angle.

[0012] Optionally, obtaining different tracking angles in combination with different north-south spacings and bracket heights includes:

[0013] The target ranges of the tracking angle, the north-south distance and the bracket height are respectively set, and different tracking angles combined with different north-south distances and bracket heights are obtained according to the target ranges.

[0014] Optionally, obtaining the ambient temperature of the bifacial photovoltaic system includes:

[0015] Arrange the surface of the ground around the bifacial photovoltaic system using sensing optical fibers to monitor the surface temperature around the bifacial photovoltaic system, and collect the ambient temperature of the back of the bifacial photovoltaic system using a fiber grating temperature sensor array fixedly arranged on the back of the bifacial photovoltaic system;

[0016] Connecting a fiber Bragg grating demodulator to the fiber Bragg grating temperature sensor array to collect temperature spatial distribution data of the fiber Bragg grating temperature sensor array, and connecting a distributed fiber temperature measurement demodulator to the sensing optical fiber to collect temperature distribution data of the sensing optical fiber;

[0017] The temperature spatial distribution data of the fiber grating temperature sensor array and the temperature distribution data of the sensing optical fiber are calibrated to form the ambient temperature of the double-sided component photovoltaic system.

[0018] Optionally, calibrating the temperature spatial distribution data of the fiber Bragg grating temperature sensor array and the temperature distribution data of the sensing optical fiber comprises:

[0019] Immersing the fiber grating temperature sensor array and a sensing optical fiber of a preset length in an ice-water compound to obtain the temperature value recorded by the fiber grating temperature sensor array and the sensing optical fiber, and immersing the fiber grating temperature sensor array and the sensing optical fiber in continuously boiling water to obtain the temperature value recorded by the fiber grating temperature sensor array and the sensing optical fiber;

[0020] According to the recorded temperature values, the sensitivity coefficient of the fiber Bragg grating temperature sensor array and the sensitivity coefficient of the sensing optical fiber are calculated respectively, and based on the sensitivity coefficient of the fiber Bragg grating temperature sensor array and the sensitivity coefficient of the sensing optical fiber, the temperature spatial distribution data of the fiber Bragg grating temperature sensor array and the temperature distribution data of the sensing optical fiber are calibrated.

[0021] Optionally, obtaining the energy efficiency evaluation result of the bifacial photovoltaic system includes:

[0022] Analyze the diffuse reflection of the environment on the back of the bifacial photovoltaic system to obtain the diffuse reflection irradiance, evaluate the dust level of the bifacial photovoltaic system to obtain the pollution loss rate, and analyze the dynamic shadow formed by the north-south distance to obtain the shadow shielding rate;

[0023] The ambient temperature, the diffuse reflection radiation, the pollution loss rate and the shadow shielding rate are input into an energy efficiency evaluation model to obtain an energy efficiency evaluation result of the bifacial component photovoltaic system.

[0024] Optionally, the formula for obtaining the diffuse reflection radiation is:

[0025] H diffuse =f×ρ g ×(i d +i b )

[0026] Among them, H diffuse is the diffuse irradiance, f is the visual factor, ρ g is the ground reflectivity, i d is the solar diffuse radiation on the horizontal plane, i b is the direct solar radiation on the horizontal plane.

[0027] Optionally, the formula for obtaining the pollution loss rate is:

[0028] C=1-η cleaned

[0029] Among them, C is the pollution loss rate, η cleaned is the component efficiency after accounting for pollution losses.

[0030] Optionally, the formula for obtaining the shadow occlusion rate is:

[0031]

[0032] Among them, D is the shadow occlusion rate, H i is the total radiation exposure, H i,adjusted To adjust the irradiance after accounting for occlusion.

[0033] Optionally, the formula for obtaining the energy efficiency evaluation result of the bifacial module photovoltaic system is:

[0034]

[0035] Among them, P actual is the energy efficiency evaluation result, P rated is the rated power of the bifacial photovoltaic system under standard test conditions, α is the temperature coefficient of the photovoltaic module, T is the actual ambient temperature, T STC is the temperature under standard test conditions, Hdiffuse is the diffuse irradiance, G ref is the reference irradiance, C is the pollution loss rate, D is the shadow occlusion rate, H i is the total radiation exposure.

[0036] The beneficial effects of the present invention are:

[0037] The present invention calculates the front and back irradiance of a bifacial photovoltaic system at different tracking angles combined with different north-south spacings and bracket heights, obtains the total irradiance of multiple bifacial photovoltaic systems, and uses the tracking angle, north-south spacing and bracket height corresponding to the maximum total irradiance as the optimal target tracking result, thereby increasing the power generation and further improving the power generation efficiency of the entire system.

[0038] The present invention obtains the energy efficiency evaluation result of the bifacial photovoltaic system by inputting the ambient temperature, diffuse reflection radiation, pollution loss rate and shadow shielding rate into the energy efficiency evaluation model, and fully considers factors such as temperature, diffuse reflection on the back of the component, dust, dynamic shadow, etc., providing a more accurate evaluation method for the system energy efficiency calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0040] Figure 1 This is a flow chart of the energy efficiency evaluation method of a photovoltaic system with a large-span flexible high bracket and bifacial components according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] It should be noted that the following implementation methods are also applicable to the energy efficiency evaluation method. The following is only an example of energy efficiency evaluation:

[0043] Power generation efficiency judgment module, photovoltaic system temperature monitoring module, photovoltaic system status monitoring module, comprehensive analysis module, performance classification module and response management module;

[0044] Power generation efficiency judgment module: monitors and obtains the real-time operation data of the photovoltaic system, and analyzes the acquired real-time operation data to determine whether the power generation of the photovoltaic system reaches the expected value; if the power generation of the photovoltaic system reaches the expected value, the actual power generation efficiency of the photovoltaic system is calculated according to the actual power generation and lighting conditions, and by comparing with the expected performance indicators, it is determined whether the overall power generation efficiency of the photovoltaic system is abnormal; Photovoltaic system temperature monitoring module: when the overall power generation efficiency of the photovoltaic system is abnormal, the temperature change rate of the inverter in the photovoltaic system is analyzed according to the shadow coverage area of ​​the photovoltaic system, the real-time fluctuation of the inverter temperature data is determined, and the stability of the inverter temperature data is evaluated; Photovoltaic system status monitoring module: when the overall power generation efficiency of the photovoltaic system is abnormal, the temperature change rate of the inverter in the photovoltaic system is analyzed according to the shadow coverage area of ​​the photovoltaic system, the real-time fluctuation of the inverter temperature data is determined, and the stability of the inverter temperature data is evaluated; Photovoltaic system status monitoring module: when the overall power generation efficiency of the photovoltaic system is abnormal When the overall power generation efficiency is abnormal, the working status of the photovoltaic panels in the photovoltaic system is analyzed according to the different working environments of the photovoltaic system, the degree of performance aging of the photovoltaic panels is determined, and the interference of the working efficiency of the photovoltaic panels is evaluated; Comprehensive analysis module: Comprehensive analysis is performed on the stability of the inverter temperature data and the interference of the working efficiency of the photovoltaic panels to evaluate whether the overall performance of the photovoltaic system is abnormal; Performance division module: According to the evaluation results, the photovoltaic system is divided into a normal performance state of the photovoltaic system and an abnormal performance state of the photovoltaic system; Response management module: When the performance of the photovoltaic system is in an abnormal state, the reduction in power generation of the photovoltaic system under the abnormal state is analyzed, the impact on the power supply is evaluated, and corresponding management plans are formulated according to the evaluation results.

[0045] Among them, in the power generation efficiency judgment module, the real-time operation data of the photovoltaic system is monitored and analyzed to determine whether the power generation of the photovoltaic system reaches the expected value; if the power generation of the photovoltaic system reaches the expected value, the actual power generation efficiency of the photovoltaic system is calculated according to the actual power generation and lighting conditions, and compared with the expected performance indicators to determine whether the overall power generation efficiency of the photovoltaic system is abnormal, specifically:

[0046] Use monitoring equipment or systems to collect real-time operating data of the photovoltaic system, including power generation, light intensity, temperature, voltage, current, etc. Record and organize the collected real-time operating data to ensure the integrity and accuracy of the data. It can be recorded every minute, every hour or every day, depending on the needs.

[0047] Determine the method for calculating expected power generation. Expected power generation is usually calculated based on parameters such as light conditions, system capacity, and component rated power. The specific calculation formula can be: Expected power generation = light intensity × system capacity × component efficiency; where light intensity is usually expressed in standard watts per square meter (W / m 2 ), system capacity in kilowatts (kW), and component efficiency in percentage.

[0048] Determine the time period for calculating the power generation, which can be every minute, every hour, every day or other time intervals as needed. Obtain the power generation data within the time period from the monitoring device or system. These data are usually in kilowatt-hours (kWh), indicating the amount of electricity generated during the time period.

[0049] Add up the power generation data obtained to get the total power generation in that time period. If the data is power generation per minute or hour, you need to add them up to get the total power generation. If the power generation data is expressed in other units, such as watt-hours (Wh), you need to convert it to kilowatt-hours (kWh) to compare with parameters such as system capacity.

[0050] Compare the actual power generation with the expected power generation. If the actual power generation is greater than or equal to the expected power generation, it means that the system is performing well, otherwise there may be problems.

[0051] It should be noted that when comparing actual and expected power generation, it is necessary to consider the impact of environmental factors on power generation, such as weather, light conditions, temperature, etc. Sometimes, environmental factors may cause the actual power generation to deviate from the expected power generation.

[0052] Calculate the actual power generation efficiency of the photovoltaic system based on the actual power generation and lighting conditions.

[0053] The calculated actual power generation efficiency is compared with the expected performance index. The expected performance index is the expected power generation efficiency of the photovoltaic system under ideal working conditions. The specific value is set by those skilled in the art according to the specific power generation situation of the photovoltaic system and will not be described in detail here.

[0054] If the actual power generation efficiency is greater than or equal to the expected performance index, it means that the overall power generation efficiency of the photovoltaic system is normal. On the contrary, if the actual power generation efficiency is less than the expected performance index, it may indicate that the performance of the photovoltaic system is abnormal.

[0055] Photovoltaic system temperature monitoring module: When the overall power generation efficiency of the photovoltaic system is abnormal, the temperature change rate of the inverter in the photovoltaic system is analyzed according to the shadow coverage area of ​​the photovoltaic system, the real-time fluctuation of the inverter temperature data is determined, and the stability of the inverter temperature data is evaluated.

[0056] Analyzing the temperature change rate of the inverter in the photovoltaic system based on the shadow coverage area of ​​the photovoltaic system means further analyzing the temperature change of the inverter taking into account the possible shadow coverage in the system. Specifically, this means that it is necessary to pay attention to the rate of change of the inverter temperature, that is, the degree of temperature change per unit time, and this change will be affected by the shadow coverage area.

[0057] Shadow coverage in the photovoltaic system will affect the reception of light, thereby affecting the heating of the photovoltaic modules. In the shadowed part, the photovoltaic modules receive less light and generate relatively less heat, which may cause the inverter temperature change rate in this part to be different from that in the normal part.

[0058] Monitor and analyze the temperature change rate data of the inverter in the shadow coverage area of ​​the photovoltaic system to determine the real-time fluctuation of the inverter temperature data. According to the temperature change rate data obtained by real-time monitoring, the temperature conversion rate fluctuation index of the inverter is obtained to evaluate the stability of the inverter temperature data. The method for obtaining the temperature conversion rate fluctuation index is as follows:

[0059] The size of the sliding window is determined according to the temperature change rate of the inverter in the shadow coverage area of ​​the photovoltaic system. If the data changes frequently, a smaller window size can be selected; if the data changes frequently, a larger window size can be selected.

[0060] For the temperature data in each sliding window, the temperature conversion rate is calculated. For each sliding window, the temperature conversion rate abnormal value is calculated according to the calculated temperature conversion rate, and the standard temperature range of the photovoltaic system inverter under the pre-set normal state is obtained. The calculated temperature conversion rate abnormal value is compared and analyzed with it, and the temperature conversion rate fluctuation index is calculated. When the calculated temperature conversion rate abnormal value is greater than the maximum temperature value of the photovoltaic system inverter under the normal state, the obtained temperature conversion rate fluctuation index is compared with the temperature conversion rate fluctuation index reference threshold. If the temperature conversion rate fluctuation index is greater than or equal to the temperature conversion rate fluctuation index reference threshold, it means that the temperature data fluctuation in the inverter is more obvious and the stability of the inverter temperature data is lower, and a temperature data abnormal signal is generated at this time; if the temperature conversion rate fluctuation index is less than the temperature conversion rate fluctuation index reference threshold, it means that the temperature data fluctuation in the inverter is less obvious and the stability of the inverter temperature data is higher, and a temperature data normal signal is generated at this time.

[0061] The temperature conversion rate fluctuation index reflects the degree of fluctuation of the inverter temperature data, that is, the degree of fluctuation of the rate of temperature change. When the temperature conversion rate fluctuation index is large, it means that the inverter temperature data fluctuates violently within a certain period of time, and the temperature change rate fluctuates significantly. This may be due to the instability of temperature changes caused by external environmental factors, system failures or other factors. Therefore, the larger the temperature conversion rate fluctuation index, the worse the stability of the inverter temperature data and the more unstable the system operation state.

[0062] Photovoltaic system status monitoring module: When the overall power generation efficiency of the photovoltaic system is abnormal, the working status of the photovoltaic panels in the photovoltaic system is analyzed according to the different working environments of the photovoltaic system, the degree of performance aging of the photovoltaic panels is determined, and the interference of the working efficiency of the photovoltaic panels is evaluated.

[0063] Conduct electrical performance tests on components in photovoltaic panels, analyze characteristic data of performance degradation of panels and obtain performance degradation sensitivity index of panels, evaluate interference with working efficiency of photovoltaic panels, take performance degradation value of panels at initial time t=1 as initial value of first performance degradation value of panels, compare and analyze performance degradation value of panels at each time with initial degradation value for each time t>1, calculate performance degradation sensitivity index of panels by exponential smoothing method, compare obtained performance degradation sensitivity index of panels with reference threshold of performance degradation sensitivity index, if performance degradation sensitivity index of panels is greater than or equal to reference threshold of performance degradation sensitivity index, it indicates that performance aging degree of photovoltaic panels is more serious, interference with working efficiency of photovoltaic panels is more obvious, and abnormal performance signal of panels is generated at this time; if performance degradation sensitivity index of panels is less than reference threshold of performance degradation sensitivity index, it indicates that performance aging degree of photovoltaic panels is less serious, interference with working efficiency of photovoltaic panels is less obvious, and normal performance signal of panels is generated at this time.

[0064] The larger the performance degradation sensitivity index is, the faster the performance of the photovoltaic panel is degraded, that is, the greater the degree of decline in the working efficiency of the photovoltaic panel is. Therefore, it indicates that the working efficiency of the photovoltaic panel is more disturbed.

[0065] In other words, when the performance degradation sensitivity index is large, the performance of the panel is unstable and may be affected by various factors, such as component aging, shadow coverage, temperature changes, etc., which will lead to a decrease in the working efficiency of the photovoltaic panel. Therefore, the performance degradation sensitivity index can be used as an indicator to evaluate the interference of the working efficiency of photovoltaic panels. The larger the index, the more obvious the interference.

[0066] Comprehensive analysis module: Comprehensively analyze the stability of inverter temperature data and the interference of photovoltaic panel working efficiency to evaluate whether the overall performance of the photovoltaic system is abnormal.

[0067] The temperature conversion rate fluctuation index and the performance degradation sensitivity index are normalized, and the abnormal evaluation coefficient of the overall performance of the photovoltaic system is calculated based on the normalized temperature conversion rate fluctuation index and the performance degradation sensitivity index.

[0068] Performance division module: Based on the evaluation results, the PV system is divided into a PV system performance normal state and a PV system performance abnormal state.

[0069] The acquired abnormal assessment coefficient of the overall performance of the photovoltaic system is compared with the reference threshold of the abnormal assessment coefficient; if the abnormal assessment coefficient of the overall performance of the photovoltaic system is greater than or equal to the reference threshold of the abnormal assessment coefficient, it means that the possibility of abnormality in the overall performance of the photovoltaic system is greater, and the photovoltaic system is classified as an abnormal photovoltaic system performance state. At this time, an abnormal photovoltaic system state signal is generated, and the performance of the photovoltaic system needs to be adjusted immediately, and the system operating parameters are optimized to improve the overall performance of the system; if the abnormal assessment coefficient of the overall performance of the photovoltaic system is less than the reference threshold of the abnormal assessment coefficient, it means that the possibility of abnormality in the overall performance of the photovoltaic system is smaller, and the photovoltaic system is classified as a normal photovoltaic system performance state. At this time, a normal photovoltaic system signal is generated, and the system performance needs to be continuously monitored to promptly discover and solve potential problems to ensure the long-term stable operation of the system.

[0070] In this embodiment, the operation data of the photovoltaic system is monitored in real time, including power generation and light conditions, to determine whether the power generation of the photovoltaic system reaches the expected value. If the power generation reaches the expected value, the system will calculate the actual power generation efficiency of the photovoltaic system and compare it with the expected performance index to determine whether the overall power generation efficiency of the photovoltaic system is normal.

[0071] If the power generation efficiency is abnormal, the system will further analyze the temperature change rate of the inverter in the photovoltaic system and evaluate the stability of the inverter temperature data. At the same time, according to the working environment of the photovoltaic system, the system will analyze the working status of the photovoltaic panels, determine the degree of performance aging, and evaluate the interference of the working efficiency of the photovoltaic panels. By comprehensively analyzing the stability of the inverter temperature data and the interference of the working efficiency of the photovoltaic panels, the system evaluates whether the overall performance of the photovoltaic system is abnormal and divides it into normal or abnormal performance status. This system can promptly detect and diagnose abnormal conditions of the photovoltaic system, provide effective decision-making support for operation and maintenance personnel, and ensure the stable operation of the photovoltaic system.

[0072] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0073] like Figure 1As shown, this embodiment discloses a method for evaluating the energy efficiency of a large-span flexible high bracket and a bifacial component photovoltaic system, including: obtaining the azimuth and altitude of the target, and determining the tracking angle of the bifacial component photovoltaic system according to the azimuth and altitude of the target; calculating the front irradiation and the back irradiation of the bifacial component photovoltaic system at different tracking angles combined with different north-south spacings and bracket heights, obtaining the total irradiation of multiple bifacial component photovoltaic systems, and taking the tracking angle, north-south spacing and bracket height corresponding to the maximum total irradiation as the optimal target tracking result; obtaining the ambient temperature, ambient diffuse reflection, dust level and dynamic shadow formed by the north-south spacing of the bifacial component photovoltaic system, performing energy efficiency evaluation based on the ambient temperature, ambient diffuse reflection, dust level and dynamic shadow formed by the north-south spacing of the bifacial component photovoltaic system, and obtaining the energy efficiency evaluation result of the bifacial component photovoltaic system.

[0074] Specifically:

[0075] This embodiment discloses a method for evaluating the energy efficiency of a photovoltaic system with a large-span flexible high bracket and a bifacial component, including:

[0076] Step 1: Set the optimal tilt angle, north-south spacing and bracket height according to local latitude and lighting conditions;

[0077] Step 2: Establish an ideal model for system energy efficiency analysis;

[0078] Step 3: Perform temperature field analysis to obtain the accurate range of the ambient temperature of the photovoltaic module;

[0079] Step 4: Analyze the diffuse reflection of the surrounding environment on the back of the component and calculate the diffuse reflection radiation;

[0080] Step 5: Evaluate the dust level on site and calculate the pollution loss rate on the front of the module;

[0081] Step 6: Analyze the dynamic shadow formed by the north-south distance and calculate the shadow occlusion rate;

[0082] Step 7: Introduce the disturbance factors calculated in steps 3, 4, 5, and 6 into the ideal model of system energy efficiency analysis, and recalculate the system energy efficiency.

[0083] Positioning and tracking: First, determine the direction and height of the target (i.e. the sun), and adjust the tracking direction of the photovoltaic system based on these data. According to different tracking angles, combined with different north-south spacing and bracket heights, calculate the total radiation on the front and back of the photovoltaic system. By comparing the total radiation under different configurations, find the tracking angle, north-south spacing and bracket height that can produce the maximum radiation as the optimal tracking configuration.

[0084] Energy efficiency evaluation: Environmental factors, including temperature, ground reflectivity, dust level, and shadow effects caused by the spacing between modules are considered. Based on these environmental parameters, the energy efficiency of the bifacial module photovoltaic system is analyzed to evaluate its performance. Finally, the energy efficiency evaluation results of the photovoltaic system are obtained to guide system design and optimization.

[0085] In short, this process involves precise sun tracking of the PV system and a comprehensive evaluation of the system’s performance taking into account a variety of environmental factors. Through these steps, the optimal system configuration can be determined and its energy efficiency performance can be evaluated.

[0086] Furthermore, the formula for determining the tracking angle of a bifacial photovoltaic system is:

[0087]

[0088] Among them, θ is the reference tracking angle of the bifacial photovoltaic module, A is the solar altitude angle, and B is the solar azimuth angle.

[0089] Further, obtaining different tracking angles in combination with different north-south spacing and bracket heights includes:

[0090] Set the target ranges of tracking angle, north-south distance and bracket height respectively, and obtain different tracking angles combined with different north-south distances and bracket heights according to the target ranges.

[0091] Furthermore, obtaining the ambient temperature of the bifacial photovoltaic system includes:

[0092] The sensing optical fiber is arranged around the surface of the bifacial photovoltaic system to monitor the surface temperature around the bifacial photovoltaic system, and the fiber grating temperature sensor array is fixedly set on the back of the bifacial photovoltaic system to collect the ambient temperature on the back of the bifacial photovoltaic system;

[0093] Connecting a fiber Bragg grating demodulator to a fiber Bragg grating temperature sensor array to collect temperature spatial distribution data of the fiber Bragg grating temperature sensor array, and connecting a distributed fiber optic temperature measurement demodulator to a sensing optical fiber to collect temperature distribution data of the sensing optical fiber;

[0094] The temperature spatial distribution data of the fiber Bragg grating temperature sensor array and the temperature distribution data of the sensing optical fiber are calibrated to form the ambient temperature of the bifacial module photovoltaic system.

[0095] Specifically:

[0096] Surface temperature monitoring: By arranging sensor optical fibers on the surface around the photovoltaic system, the surface temperature can be monitored in real time.

[0097] Back ambient temperature collection: A fiber Bragg grating temperature sensor array is installed on the back of the photovoltaic system to collect the back ambient temperature data.

[0098] Temperature data acquisition and demodulation: Use a fiber Bragg grating demodulator to connect to the sensor array to collect the temperature spatial distribution data in the sensor array. At the same time, connect a distributed fiber temperature measurement demodulator to the sensing fiber to collect the temperature distribution data of the sensing fiber.

[0099] Data calibration and integration: Calibrate the temperature data collected by the sensor array and sensing fiber to ensure data accuracy. Integrate the calibrated data to form a comprehensive view of the ambient temperature of the photovoltaic system.

[0100] In short, the process involves using fiber optic sensors to monitor the temperature of the ground and backside of the photovoltaic system, collecting and calibrating these data through a demodulator, and ultimately forming an accurate description of the ambient temperature of the photovoltaic system. Such a monitoring system helps to more accurately understand and optimize the performance of the photovoltaic system under different environmental conditions.

[0101] Furthermore, calibrating the temperature spatial distribution data of the fiber Bragg grating temperature sensor array and the temperature distribution data of the sensing optical fiber includes:

[0102] Immersing a fiber Bragg grating temperature sensor array and a sensing optical fiber of a preset length in an ice-water compound to obtain a temperature value recorded by the fiber Bragg grating temperature sensor array and the sensing optical fiber, and immersing the fiber Bragg grating temperature sensor array and the sensing optical fiber in continuously boiling water to obtain a temperature value recorded by the fiber Bragg grating temperature sensor array and the sensing optical fiber;

[0103] According to the recorded temperature values, the sensitivity coefficient of the fiber Bragg grating temperature sensor array and the sensitivity coefficient of the sensing optical fiber are calculated respectively. Based on the sensitivity coefficient of the fiber Bragg grating temperature sensor array and the sensitivity coefficient of the sensing optical fiber, the temperature spatial distribution data of the fiber Bragg grating temperature sensor array and the temperature distribution data of the sensing optical fiber are calibrated.

[0104] Specifically:

[0105] Surface temperature monitoring: By arranging sensor optical fibers on the surface around the photovoltaic system, the surface temperature can be monitored in real time.

[0106] Back ambient temperature collection: A fiber Bragg grating temperature sensor array is installed on the back of the photovoltaic system to collect the back ambient temperature data.

[0107] Temperature data acquisition and demodulation: Use a fiber Bragg grating demodulator to connect to the sensor array to collect the temperature spatial distribution data in the sensor array. At the same time, connect a distributed fiber temperature measurement demodulator to the sensing fiber to collect the temperature distribution data of the sensing fiber.

[0108] Data calibration and integration: Calibrate the temperature data collected by the sensor array and sensing fiber to ensure data accuracy. Integrate the calibrated data to form a comprehensive view of the ambient temperature of the photovoltaic system.

[0109] In short, the process involves using fiber optic sensors to monitor the temperature of the ground and backside of the photovoltaic system, collecting and calibrating these data through a demodulator, and ultimately forming an accurate description of the ambient temperature of the photovoltaic system. Such a monitoring system helps to more accurately understand and optimize the performance of the photovoltaic system under different environmental conditions.

[0110] Furthermore, the energy efficiency evaluation results of the bifacial photovoltaic system are obtained including:

[0111] Analyze the diffuse reflection of the back environment of the bifacial photovoltaic system to obtain the diffuse reflection irradiance, evaluate the dust level of the bifacial photovoltaic system to obtain the pollution loss rate, and analyze the dynamic shadow formed by the north-south distance to obtain the shadow shielding rate;

[0112] The ambient temperature, diffuse radiation, contamination loss rate and shadow shielding rate are input into the energy efficiency evaluation model to obtain the energy efficiency evaluation results of the bifacial module photovoltaic system.

[0113] Furthermore, the formula for obtaining diffuse reflection irradiance is:

[0114] H diffuse =f×ρ g ×(i d +i b )

[0115] Among them, H diffuse is the diffuse irradiance, f is the visual factor, ρ g is the ground reflectivity, i d is the solar diffuse radiation on the horizontal plane, i b is the direct solar radiation on the horizontal plane.

[0116] Furthermore, the formula for obtaining the pollution loss rate is:

[0117] C=1-η cleaned

[0118] Among them, C is the pollution loss rate, η cleaned is the component efficiency after accounting for pollution losses.

[0119] Furthermore, the formula for obtaining the shadow occlusion rate is:

[0120]

[0121] Among them, D is the shadow occlusion rate, Hi is the total radiation exposure, H i,adjusted To adjust the irradiance after accounting for occlusion.

[0122] Furthermore, the formula for obtaining the energy efficiency evaluation result of the bifacial photovoltaic system is:

[0123]

[0124] Among them, P actual is the energy efficiency evaluation result, P rated is the rated power of the bifacial photovoltaic system under standard test conditions, α is the temperature coefficient of the photovoltaic module, T is the actual ambient temperature, T STC is the temperature under standard test conditions, H diffuse is the diffuse irradiance, G ref is the reference irradiance, C is the pollution loss rate, D is the shadow occlusion rate, H i is the total radiation exposure.

[0125] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for evaluating the energy efficiency of a photovoltaic system with a large-span flexible high bracket and bifacial components, characterized in that: include: Acquiring the azimuth and altitude of the target, and determining the tracking angle of the bifacial module photovoltaic system according to the azimuth and altitude of the target; Calculate the front and back irradiance of the bifacial photovoltaic system at different tracking angles combined with different north-south spacings and bracket heights, obtain the total irradiance of multiple bifacial photovoltaic systems, and take the tracking angle, north-south spacing and bracket height corresponding to the maximum total irradiance as the best target tracking result; The ambient temperature, ambient diffuse reflection, dust level and dynamic shadows formed by the north-south distance of the bifacial component photovoltaic system are obtained, and energy efficiency evaluation is performed based on the ambient temperature, ambient diffuse reflection, dust level and dynamic shadows formed by the north-south distance of the bifacial component photovoltaic system to obtain the energy efficiency evaluation result of the bifacial component photovoltaic system.

2. The method for evaluating the energy efficiency of a photovoltaic system with a large-span flexible high bracket and bifacial components according to claim 1 is characterized in that: The formula for determining the tracking angle of the bifacial photovoltaic system is: Among them, θ is the reference tracking angle of the bifacial photovoltaic module, A is the solar altitude angle, and B is the solar azimuth angle.

3. The method for evaluating the energy efficiency of a photovoltaic system with a large-span flexible high bracket and bifacial components according to claim 1 is characterized in that: Acquiring different tracking angles combined with different north-south spacing and bracket heights includes: The target ranges of the tracking angle, the north-south distance and the bracket height are respectively set, and different tracking angles combined with different north-south distances and bracket heights are obtained according to the target ranges.

4. The method for evaluating energy efficiency of a photovoltaic system with a large-span flexible high bracket and bifacial components according to claim 1 is characterized in that: Obtaining the ambient temperature of the bifacial photovoltaic system includes: Arrange the surface of the ground around the bifacial photovoltaic system using sensing optical fibers to monitor the surface temperature around the bifacial photovoltaic system, and collect the ambient temperature of the back of the bifacial photovoltaic system using a fiber grating temperature sensor array fixedly arranged on the back of the bifacial photovoltaic system; Connecting a fiber Bragg grating demodulator to the fiber Bragg grating temperature sensor array to collect temperature spatial distribution data of the fiber Bragg grating temperature sensor array, and connecting a distributed fiber temperature measurement demodulator to the sensing optical fiber to collect temperature distribution data of the sensing optical fiber; The temperature spatial distribution data of the fiber grating temperature sensor array and the temperature distribution data of the sensing optical fiber are calibrated to form the ambient temperature of the double-sided component photovoltaic system.

5. The method for evaluating the energy efficiency of a photovoltaic system with a large-span flexible high bracket and a bifacial module according to claim 4 is characterized in that: Calibrating the temperature spatial distribution data of the fiber grating temperature sensor array and the temperature distribution data of the sensing optical fiber includes: Immersing the fiber grating temperature sensor array and a sensing optical fiber of a preset length in an ice-water compound to obtain the temperature value recorded by the fiber grating temperature sensor array and the sensing optical fiber, and immersing the fiber grating temperature sensor array and the sensing optical fiber in continuously boiling water to obtain the temperature value recorded by the fiber grating temperature sensor array and the sensing optical fiber; According to the recorded temperature values, the sensitivity coefficient of the fiber Bragg grating temperature sensor array and the sensitivity coefficient of the sensing optical fiber are calculated respectively, and based on the sensitivity coefficient of the fiber Bragg grating temperature sensor array and the sensitivity coefficient of the sensing optical fiber, the temperature spatial distribution data of the fiber Bragg grating temperature sensor array and the temperature distribution data of the sensing optical fiber are calibrated.

6. The method for evaluating energy efficiency of a photovoltaic system with a large-span flexible high bracket and bifacial components according to claim 1 is characterized in that: Obtaining the energy efficiency evaluation results of the bifacial photovoltaic system includes: Analyze the diffuse reflection of the environment on the back of the bifacial photovoltaic system to obtain the diffuse reflection irradiance, evaluate the dust level of the bifacial photovoltaic system to obtain the pollution loss rate, and analyze the dynamic shadow formed by the north-south distance to obtain the shadow shielding rate; The ambient temperature, the diffuse reflection radiation, the pollution loss rate and the shadow shielding rate are input into an energy efficiency evaluation model to obtain an energy efficiency evaluation result of the bifacial component photovoltaic system.

7. The method for evaluating energy efficiency of a photovoltaic system with a large-span flexible high bracket and bifacial components according to claim 6 is characterized in that: The formula for obtaining the diffuse reflection irradiance is: H diffuse =f×ρ g ×(i d +i b ) Among them, H diffuse is the diffuse irradiance, f is the visual factor, ρ g is the ground reflectivity, i d is the solar diffuse radiation on the horizontal plane, i b is the direct solar radiation on the horizontal plane.

8. The method for evaluating energy efficiency of a photovoltaic system with a large-span flexible high bracket and bifacial components according to claim 6 is characterized in that: The formula for obtaining the pollution loss rate is: C=1-th cleaned Among them, C is the pollution loss rate, η cleaned is the component efficiency after accounting for pollution losses.

9. The method for evaluating energy efficiency of a photovoltaic system with a large-span flexible high bracket and bifacial components according to claim 6 is characterized in that: The formula for obtaining the shadow occlusion rate is: Among them, D is the shadow occlusion rate, H i is the total radiation exposure, H i,adjusted To adjust the irradiance after accounting for occlusion.

10. The method for evaluating energy efficiency of a photovoltaic system with a large-span flexible high bracket and bifacial components according to claim 6, characterized in that: The formula for obtaining the energy efficiency evaluation result of the bifacial photovoltaic system is: Among them, P actual is the energy efficiency evaluation result, P rated is the rated power of the bifacial photovoltaic system under standard test conditions, α is the temperature coefficient of the photovoltaic module, T is the actual ambient temperature, T STC is the temperature under standard test conditions, H diffuse is the diffuse irradiance, G ref is the reference irradiance, C is the pollution loss rate, D is the shadow occlusion rate, H i is the total radiation exposure.

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