Photovoltaic module operation temperature on-line monitoring system

Abstract

The invention relates to the technical field of photovoltaic module monitoring, and discloses a photovoltaic module operation temperature on-line monitoring system, which comprises a string type inverter, a temperature testing device, an environmental interference elimination module, a fault early warning module and a monitoring system, the string type inverter is used for converting direct current generated by the photovoltaic module into alternating current; the temperature testing device leads out a temperature testing line from the string type inverter and is installed on the back face of the photovoltaic module nearby so as to collect temperature data of the photovoltaic module. The temperature data of the plurality of assemblies collected by the temperature test module and other operation data of the inverter are uploaded to the monitoring system through the inverter communication interface. According to the invention, the module temperature testing device is additionally arranged on a conventional inverter, and the module temperature testing device and other operation data of the inverter are uploaded to the monitoring system together, so that the number of testing equipment and data acquisition equipment is reduced, the cost is reduced, the real-time monitoring of the operation temperature of the photovoltaic module is realized, and the operation is convenient.

Description

Technical Field

[0001] The invention relates to the technical field of photovoltaic component monitoring, and in particular to an online monitoring system for operating temperature of a photovoltaic component. Background Art

[0002] As the global demand for renewable energy continues to grow, photovoltaic power generation has been widely used as a clean and sustainable form of energy. Photovoltaic modules are the core components of photovoltaic power generation systems. Their performance and reliability directly affect the power generation efficiency and stability of the entire system. Excessive temperature will reduce the power generation efficiency of photovoltaic modules, shorten their service life, and may even cause component damage and fire and other safety accidents. Therefore, real-time monitoring of the operating temperature of photovoltaic modules and timely detection of temperature abnormalities are of great significance to improving the operating efficiency and safety of photovoltaic power stations.

[0003] Traditional photovoltaic module temperature monitoring methods generally include the following two methods: first, offline testing, which mostly uses a handheld temperature gun or infrared thermal imager, etc. The disadvantages are large errors and the inability to test continuously. Second, separate online testing equipment is arranged to monitor the operating temperature of the components. The disadvantages are high cost and complexity. Separate data acquisition and transmission equipment is often required to upload the monitoring data to the production management system or test analysis system. In addition, the above test system is greatly affected by environmental factors and it is difficult to provide real-time warning of faults. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an online monitoring system for the operating temperature of a photovoltaic module, which solves the deficiencies in accuracy, economy and safety of the existing photovoltaic module temperature monitoring system.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a photovoltaic module operating temperature online monitoring system, including a string inverter, a temperature testing device, an environmental interference elimination module, a fault warning module and a monitoring system; the string inverter is used to convert the direct current generated by the photovoltaic module into alternating current; the temperature testing device leads the temperature test line from the string inverter and is installed nearby on the back of the photovoltaic module to collect temperature data of the photovoltaic module; the environmental interference elimination module is used to eliminate the interference of external environmental factors on the temperature test; the fault warning module is used to issue a warning when an abnormal situation is detected; the temperature data of multiple components collected by the temperature testing module are uploaded to the monitoring system through the inverter communication interface together with other operating data of the inverter.

[0006] Preferably, the temperature testing device includes a temperature testing sensor and a data transmission line. The temperature testing sensor can accurately measure the temperature on the back of the photovoltaic module and transmit the temperature data to the string inverter through the data transmission line.

[0007] Preferably, the environmental interference elimination module includes a temperature compensation unit and an interference filtering unit. The temperature compensation unit is used to compensate for errors caused by changes in ambient temperature, and the interference filtering unit is used to filter out adverse effects of external electromagnetic interference on temperature testing.

[0008] Preferably, the temperature compensation unit establishes a temperature compensation model to compensate the measured temperature in real time according to the ambient temperature and light intensity factors. The temperature compensation model collects ambient temperature data T env And the light intensity data I are calculated by the following algorithm formula to calculate the compensated temperature T compensated :

[0009] T compensated =T measured +k1×(T env -T reference )+k2×(II reference )

[0010] Among them, T measured is the temperature value measured by the temperature test sensor, T reference is the reference ambient temperature, I reference is the reference light intensity, k1 and k2 are compensation coefficients, which are determined by fitting the experimental data.

[0011] Preferably, the fault warning module includes an abnormality judgment unit and a warning notification unit. The abnormality judgment unit judges whether there is a fault risk based on a preset temperature threshold and change trend. The warning notification unit issues a warning to relevant personnel through sound, light and communication when an abnormal situation is detected.

[0012] Preferably, the judgment method of the abnormality judgment unit includes the following steps:

[0013] S1. Continuously receive the photovoltaic module temperature data T and the ambient temperature data T collected by the temperature test device env and light intensity data I, determine the time window size t window , used to analyze temperature change trends;

[0014] S2. Calculate the average temperature T avg : In time window t window The temperature data T is averaged, that is, T avg=sum(T) / n, where sum(T) is the sum of the temperature data in the time window and n is the number of data points; calculate the temperature change rate T rate : Calculate the rate of change of temperature within the time window, T rate =(T end -T start ) / t window , where T end is the temperature at the end of the time window, T start is the temperature at the beginning of the time window;

[0015] S3. Determine the upper limit of the normal temperature range T based on the characteristics of the photovoltaic modules and historical data and experience max(normal) and lower limit T min(normal) , set the warning temperature threshold T warning and the dangerous temperature threshold T danger ;

[0016] S4. When T>T warning When T rate >k*T avg , k is the empirical coefficient, indicating that the temperature changes too quickly and there is a greater risk of failure; considering the influence of environmental factors: if (TT avg(env)) / T avg(env) >m, m is another empirical coefficient, T avg(env) is the average value of the ambient temperature, and the light intensity does not change much, indicating that the temperature of the PV module is abnormally high relative to the ambient temperature, and there may also be a fault;

[0017] S5. If it is judged to be a normal situation, continue monitoring; if it is judged that there may be an abnormal situation, pass the information to the early warning notification unit and mark it as an "early warning" state; if it is judged that there is a large risk of failure, mark it as a "dangerous" state and immediately trigger the early warning notification unit for an emergency warning.

[0018] Preferably, the communication interface adopts wireless communication technology, including but not limited to Bluetooth, Wi-Fi and ZigBee, so as to achieve remote data transmission and monitoring.

[0019] Preferably, the monitoring system includes a data receiving unit, a storage unit and a display unit, the data receiving unit is used to receive temperature data and operating data from the string inverter, the storage unit is used to store historical data, and the display unit is used to display the temperature of the photovoltaic module and the operating status of the inverter in real time.

[0020] The present invention provides a photovoltaic module operating temperature online monitoring system, which has the following beneficial effects:

[0021] 1. The present invention adds a component temperature testing device to a conventional inverter, and uploads the component temperature testing device to the monitoring system together with other operating data of the inverter through the inverter communication interface, thereby reducing the number of testing equipment and data acquisition equipment, reducing costs, and expanding the inverter function. It can realize real-time monitoring of the operating temperature of photovoltaic components, and the testing process is relatively simple and easy to operate.

[0022] 2. The present invention adopts a temperature compensation model to perform real-time compensation for the measured temperature according to the ambient temperature and light intensity, thereby reducing the impact of environmental factors on temperature measurement and improving the accuracy of temperature monitoring. At the same time, the interference filtering unit filters out adverse effects such as external electromagnetic interference, further improving the reliability of temperature monitoring.

[0023] 3. Real-time monitoring of the operating temperature of photovoltaic modules, timely detection of abnormal temperature, and taking appropriate measures to deal with it, avoiding problems such as module damage and reduced power generation efficiency caused by excessive temperature, and improving the operating efficiency and safety of photovoltaic power stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a system block diagram of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the specification 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.

[0026] Example:

[0027] Please see attached Figure 1 The embodiment of the present invention provides an online monitoring system for the operating temperature of a photovoltaic module, including a string inverter, a temperature testing device, an environmental interference elimination module, a fault warning module and a monitoring system; the string inverter is used to convert the direct current generated by the photovoltaic module into alternating current; the temperature testing device leads a temperature testing line from the string inverter and is installed nearby on the back of the photovoltaic module to collect temperature data of the photovoltaic module; the environmental interference elimination module is used to eliminate the interference of external environmental factors on the temperature test; the fault warning module is used to issue a warning when an abnormal situation is detected; the temperature data of multiple components collected by the temperature testing module are uploaded to the monitoring system together with other operating data of the inverter through the inverter communication interface, the temperature testing device includes a temperature testing sensor and a data transmission line, the temperature testing sensor can accurately measure the temperature on the back of the photovoltaic module, and transmit the temperature data to the string inverter through the data transmission line.

[0028] Specifically, in a photovoltaic power station, according to the layout and power requirements of the photovoltaic modules, string inverters are installed to ensure that the inverter can stably convert the DC power generated by the photovoltaic modules into AC power and has good heat dissipation and protection performance. The temperature test line is led out from the string inverter, and the temperature test sensor is installed on the back of the photovoltaic module. A high-precision, high-stability thermistor or thermocouple is selected as the temperature test sensor to ensure the accuracy of temperature measurement. At the same time, ensure that the connection of the temperature test line is firm and reliable to avoid affecting the transmission of temperature data due to looseness or poor contact. The temperature compensation unit and the interference filtering unit are integrated into the monitoring system. In the system, the temperature compensation unit collects ambient temperature data and light intensity data, establishes a temperature compensation model, and performs real-time compensation on the temperature test data. The interference filtering unit uses electromagnetic shielding and filtering technology to filter out the adverse effects of external electromagnetic interference on the temperature test. The fault warning module determines in real time whether there is a risk of failure in the photovoltaic module and sends a warning to relevant personnel through sound, light and communication when an abnormal situation is detected. The monitoring system uses wireless communication technology to receive temperature data and operating data from the string inverter, and displays the temperature of the photovoltaic module and the operating status of the inverter in real time, which is convenient for monitoring personnel to conduct real-time monitoring.

[0029] The environmental interference elimination module includes a temperature compensation unit and an interference filtering unit. The temperature compensation unit is used to compensate for the error caused by the change of environmental temperature, and the interference filtering unit is used to filter out the adverse effects of external electromagnetic interference on temperature testing.

[0030] The temperature compensation unit establishes a temperature compensation model to compensate the measured temperature in real time according to the ambient temperature and light intensity factors. The temperature compensation model collects ambient temperature data T env And the light intensity data I are calculated by the following algorithm formula to calculate the compensated temperature T compensated :

[0031] T compensated =T measured +k1×(T env -T reference )+k2×(II reference )

[0032] Among them, T measured is the temperature value measured by the temperature test sensor, T reference is the reference ambient temperature, I reference is the reference light intensity, k1 and k2 are compensation coefficients, which are determined by fitting the experimental data.

[0033] Specifically, in this temperature compensation model, ambient temperature and light intensity are considered to be the main factors affecting the temperature measurement of photovoltaic modules. By collecting the actual ambient temperature data T envThe light intensity data I is compared with the reference value, and the measured temperature is corrected using the compensation coefficients k1 and k2, referring to the ambient temperature T reference and the reference light intensity I reference It can be set according to the actual application scenario. Usually, the stable value under specific conditions can be selected or the average value can be obtained through multiple measurements. The determination of compensation coefficients k1 and k2 requires fitting of experimental data. The temperature of photovoltaic modules can be measured under different ambient temperatures and light intensities, and compared with the actual standard temperature. Then, the data fitting method such as the least squares method can be used to determine the optimal compensation coefficients k1 and k2, so that the compensated temperature value T compensated As close to the actual temperature as possible. By establishing a temperature compensation model, the accuracy of photovoltaic module temperature measurement can be effectively improved, and the error caused by changes in environmental factors can be reduced, thereby improving the reliability and stability of the entire online monitoring system.

[0034] The fault warning module includes an abnormality judgment unit and a warning notification unit. The abnormality judgment unit judges whether there is a fault risk based on the preset temperature threshold and change trend. The warning notification unit issues a warning to relevant personnel through sound, light and communication when an abnormal situation is detected.

[0035] The determination method of the abnormality determination unit comprises the following steps:

[0036] S1. Continuously receive the photovoltaic module temperature data T and the ambient temperature data T collected by the temperature test device env and light intensity data I, determine the time window size t window , used to analyze temperature change trends;

[0037] S2. Calculate the average temperature T avg : In time window t window The temperature data T is averaged, that is, T avg =sum(T) / n, where sum(T) is the sum of the temperature data in the time window and n is the number of data points; calculate the temperature change rate T rate : Calculate the rate of change of temperature within the time window, T rate =(T end -T start ) / t window , where T end is the temperature at the end of the time window, T start is the temperature at the beginning of the time window;

[0038] S3. Determine the upper limit of the normal temperature range T based on the characteristics of the photovoltaic modules and historical data and experience max(normal) and lower limit T min(normal) , set the warning temperature threshold Twarning and the dangerous temperature threshold T danger ;

[0039] S4. When T>T warning When T rate >k*T avg , k is the empirical coefficient, indicating that the temperature changes too quickly and there is a greater risk of failure; considering the influence of environmental factors: if (TT avg(env)) / T avg(env) >m, m is another empirical coefficient, T avg(env) is the average value of the ambient temperature, and the light intensity does not change much, indicating that the temperature of the PV module is abnormally high relative to the ambient temperature, and there may also be a fault;

[0040] Specifically, the normal temperature range is determined to be 25°C-45°C, the warning temperature threshold is 50°C, the dangerous temperature threshold is 60°C, the time window is 30 minutes, k is 0.1, and m is 0.5. If the current temperature is 52°C, the average temperature is 40°C, the temperature change rate is 0.2°C / minute, and the average ambient temperature is 30°C, then the judgment is:

[0041] First, 52°C is greater than the warning temperature threshold of 50°C, and it is preliminarily judged that there may be an abnormality;

[0042] Calculate the relationship between the temperature change rate and the average temperature: 0.2℃ / minute is less than 0.1*40℃=4℃ / minute, indicating that the temperature change rate is within the acceptable range;

[0043] Considering environmental factors: (52℃-40℃) / 40℃=0.3, which is greater than 0.5*(30℃-40℃) / 40℃=-0.25, it means that the temperature of the PV module is abnormally high relative to the ambient temperature. Comprehensively judging, there is a great risk of failure, and the early warning notification unit should be triggered for emergency warning.

[0044] S5. If it is judged to be a normal situation, continue monitoring; if it is judged that there may be an abnormal situation, pass the information to the early warning notification unit and mark it as an "early warning" state; if it is judged that there is a large risk of failure, mark it as a "dangerous" state and immediately trigger the early warning notification unit for an emergency warning.

[0045] The communication interface uses wireless communication technology, including but not limited to Bluetooth, Wi-Fi and ZigBee, to achieve remote data transmission and monitoring.

[0046] The monitoring system includes a data receiving unit, a storage unit and a display unit. The data receiving unit is used to receive temperature data and operation data from the string inverter, the storage unit is used to store historical data, and the display unit is used to display the temperature of the photovoltaic module and the operating status of the inverter in real time.

[0047] Through the above specific embodiments, the present invention adds a component temperature testing device to a conventional inverter, and multiple component temperature data collected on the temperature testing module are uploaded to the monitoring system together with other operating data of the inverter through the inverter communication interface, thereby realizing real-time and accurate monitoring of the operating temperature of the photovoltaic components, timely discovering potential faults, and improving the operating efficiency and safety of the photovoltaic power station.

[0048] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A photovoltaic module operating temperature online monitoring system, characterized in that: It includes a string inverter, a temperature testing device, an environmental interference elimination module, a fault warning module and a monitoring system; the string inverter is used to convert the direct current generated by the photovoltaic module into alternating current; the temperature testing device leads the temperature testing line from the string inverter and is installed nearby on the back of the photovoltaic module to collect temperature data of the photovoltaic module; the environmental interference elimination module is used to eliminate the interference of external environmental factors on the temperature test; the fault warning module is used to issue a warning when an abnormal situation is detected; the temperature data of multiple components collected by the temperature testing module are uploaded to the monitoring system through the inverter communication interface together with other operating data of the inverter.

2. A photovoltaic module operating temperature online monitoring system according to claim 1, characterized in that: The temperature testing device comprises a temperature testing sensor and a data transmission line. The temperature testing sensor can accurately measure the temperature on the back of the photovoltaic module and transmit the temperature data to the string inverter through the data transmission line.

3. A photovoltaic module operating temperature online monitoring system according to claim 1, characterized in that: The environmental interference elimination module includes a temperature compensation unit and an interference filtering unit. The temperature compensation unit is used to compensate for errors caused by changes in environmental temperature, and the interference filtering unit is used to filter out adverse effects of external electromagnetic interference on temperature testing.

4. A photovoltaic module operating temperature online monitoring system according to claim 3, characterized in that: The temperature compensation unit establishes a temperature compensation model to compensate the measured temperature in real time according to the ambient temperature and light intensity factors. The temperature compensation model collects ambient temperature data T env And the light intensity data I are calculated by the following algorithm formula to calculate the compensated temperature T compensated : T compensated =T measured +k1×(T env -T reference )+k2×(I-I reference ) Among them, T measured is the temperature value measured by the temperature test sensor, T reference is the reference ambient temperature, I reference is the reference light intensity, k1 and k2 are compensation coefficients, which are determined by fitting the experimental data.

5. The photovoltaic module operating temperature online monitoring system according to claim 1, characterized in that: The fault warning module includes an abnormality judgment unit and a warning notification unit. The abnormality judgment unit judges whether there is a fault risk based on a preset temperature threshold and change trend. The warning notification unit issues a warning to relevant personnel through sound, light and communication when an abnormal situation is detected.

6. A photovoltaic module operating temperature online monitoring system according to claim 5, characterized in that: The determination method of the abnormality determination unit comprises the following steps: S1. Continuously receive the photovoltaic module temperature data T and the ambient temperature data T collected by the temperature test device env and light intensity data I, determine the time window size t window , used to analyze temperature change trends; S2. Calculate the average temperature T avg : In time window t window The temperature data T is averaged, that is, T avg =sum(T) / n, where sum(T) is the sum of the temperature data in the time window and n is the number of data points; calculate the temperature change rate T rate : Calculate the rate of change of temperature within the time window, T rate =(T end -T start ) / t window , where T end is the temperature at the end of the time window, T start is the temperature at the beginning of the time window; S3. Determine the upper limit of the normal temperature range T based on the characteristics of the photovoltaic modules and historical data and experience max(normal) and lower limit T min(normal) , set the warning temperature threshold T warning and the dangerous temperature threshold T danger ; S4. When T>T warning When T rate >k*T avg , k is the empirical coefficient, indicating that the temperature changes too quickly and there is a greater risk of failure; considering the influence of environmental factors: if (TT avg(env)) / T avg(env) >m, m is another empirical coefficient, T avg(env) is the average value of the ambient temperature, and the light intensity does not change much, indicating that the temperature of the PV module is abnormally high relative to the ambient temperature, and there may also be a fault; S5. If it is judged to be normal, continue monitoring; if it is judged that there may be an abnormal situation, pass the information to the early warning notification unit and mark it as "alarm" status; if it is judged that there is a large risk of failure, mark it as "dangerous" status and immediately trigger the early warning notification unit for emergency warning.

7. The photovoltaic module operating temperature online monitoring system according to claim 1, characterized in that: The communication interface uses wireless communication technology, including but not limited to Bluetooth, Wi-Fi and ZigBee, to achieve remote data transmission and monitoring.

8. The photovoltaic module operating temperature online monitoring system according to claim 1, characterized in that: The monitoring system includes a data receiving unit, a storage unit and a display unit. The data receiving unit is used to receive temperature data and operation data from the string inverter, the storage unit is used to store historical data, and the display unit is used to display the temperature of the photovoltaic module and the operating status of the inverter in real time.

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