A photovoltaic micro-inverter anti-reverse flow monitoring method

Abstract

The present invention relates to the field of backflow prevention monitoring technology, specifically a photovoltaic micro-inverter backflow prevention monitoring method, comprising the following steps: collecting real-time data between the inverter and the power grid through a Hall sensor, the real-time data including voltage, current and frequency, calculating the current power balance state according to the real-time data, and generating a real-time power state; based on the real-time power state, detecting whether there is a potential backflow risk. In the present invention, a Hall sensor is used to obtain the voltage, current and frequency data of the power grid and the inverter, and the backflow risk is calculated in combination with the power balance state, so that data collection can reflect instantaneous power flow and reduce the monitoring blind area caused by fixed collection intervals. Based on the analysis results of the power flow direction, the output power threshold is dynamically adjusted so that the inverter can respond quickly when the power feedback fluctuates, avoiding power feedback imbalance caused by unreasonable threshold setting.

Description

Technical Field

[0001] The present invention relates to the technical field of backflow prevention monitoring, and in particular to a backflow prevention monitoring method for a photovoltaic micro inverter. Background Art

[0002] The field of anti-backflow monitoring technology involves power systems, distributed energy management and smart grid control. It mainly studies the power regulation, flow control and safe operation strategy when grid-connected power sources (such as photovoltaic inverters, wind turbines, etc.) transmit electricity to the public power grid. The photovoltaic micro-inverter anti-backflow monitoring method is an intelligent control technology designed for photovoltaic grid-connected systems. It collects real-time data such as voltage, current, frequency, etc. between the inverter and the grid through sensors, analyzes the power flow direction, and dynamically adjusts the output power of the inverter to avoid the occurrence of backflow.

[0003] In the prior art, the optimization of the inverter working mode relies on the adjustment of fixed parameters, and does not fully consider the impact of environmental factors. This may make it difficult to adjust the operating mode in time when the light or temperature changes, reducing the stability of the power output. The sensor data acquisition frequency is fixed, which is difficult to adapt to the data update requirements under different load conditions. This may lead to insufficient data under high load conditions and redundant data under low load conditions, increasing the computing pressure and reducing the monitoring accuracy. Therefore, improvements are needed. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings existing in the prior art and to propose a photovoltaic micro-inverter anti-backflow monitoring method.

[0005] In order to achieve the above object, the present invention adopts the following technical solution, a photovoltaic micro-inverter anti-backflow monitoring method, comprising the following steps: The real-time data between the inverter and the power grid is collected through the Hall sensor, and the real-time data includes voltage, current and frequency. The current power balance state is calculated based on the real-time data to generate a real-time power state. Based on the real-time power state, whether there is a potential reverse flow risk is detected, and the output power threshold of the inverter is dynamically adjusted to obtain the adjusted output power threshold. Based on the adjusted output power threshold, monitor the output power of the inverter and generate a monitoring result; according to the monitoring result, in combination with the ambient temperature and the ambient light intensity, adjust the working mode of the inverter to obtain an optimized working mode; Comparing the optimized working mode with the operation data, analyzing the performance under different environmental conditions, and generating a mode performance analysis result; adjusting the data collection frequency of the Hall sensor according to the mode performance analysis result, and establishing an adjusted sensor configuration; Based on the adjusted sensor configuration, the anti-reverse flow performance between the inverter and the grid is re-evaluated to generate a system evaluation result.

[0006] Preferably, the steps of acquiring the real-time power status are: Collect the instantaneous voltage, current and frequency data of the inverter output end and the grid input end respectively, store the collected instantaneous voltage value, current value and frequency value into the data buffer area, and obtain the real-time monitoring data set; Based on the real-time monitoring data set, the current power balance state is calculated using the following formula: ; in, Representative moments The electrical energy balance state, Representative moments The instantaneous voltage value of the inverter output terminal, Representative moments The instantaneous current value of the inverter output, Representative moments The phase angle between the inverter output and the grid input, Representative moments The impedance on the inverter side, Representative moments The impedance of the grid side, Representative moments Reactive power on the inverter side, Representative moments Active power on the inverter side, For decimal values, prevent the denominator from being zero; Based on the power balance state, the stability of current power transmission is determined and a real-time power state is generated.

[0007] Preferably, the step of obtaining the adjusted output power threshold is: According to the real-time power state, the potential reverse flow risk score is calculated, and the calculation formula is: ; in, represents the potential backflow risk score, represents the instantaneous power at the inverter output, represents the instantaneous power at the grid input, Represents the power response time on the inverter side, represents the power response time on the grid side, represents the equivalent capacitance on the inverter side, represents the equivalent inductance on the grid side, represents the equivalent impedance on the inverter side, Represents the equivalent impedance on the grid side; According to the potential reverse flow risk score, it is determined whether to adjust the inverter output power threshold to obtain an adjusted output power threshold.

[0008] Preferably, the steps of obtaining the monitoring results are: Based on the adjusted output power threshold, real-time power data of the inverter output end is called, the deviation between the current output power and the adjusted output power threshold is calculated, and the data is divided into intervals after being arranged in chronological order to form power deviation trend data; According to the power deviation trend data, the power fluctuation amplitude in each interval is calculated, and the classification standard is set according to the fluctuation amplitude, and the interval is divided into stable, fluctuating and abnormal to form a monitoring result.

[0009] Preferably, the steps for obtaining the optimized working mode are: According to the monitoring results, the current ambient temperature value and the ambient light intensity value are obtained, and the current working mode parameters of the inverter are extracted, including output power, working frequency and heat dissipation load level, to form an environment and inverter working state data set; Based on the environment and inverter working state data set, the working mode adjustment index is calculated, and the calculation formula is: ; in, Represents the working mode adjustment index, Represents the current ambient temperature. Represents the nominal operating temperature of the inverter, represents the instantaneous load level of the inverter heat dissipation, Represents the maximum heat dissipation capacity of the inverter. Represents the current ambient light intensity. Represents the current inverter output power, represents the power stability parameter on the inverter side, Represents the power fluctuation amplitude on the inverter side; Based on the working mode adjustment index, the adaptability of the current inverter working mode is analyzed, the influence of different working parameters on the inverter power output and heat dissipation load is evaluated, the output power and the working frequency are set, and the optimized working mode is obtained.

[0010] Preferably, the steps for obtaining the model performance analysis results are: According to the optimized working mode, the mode performance score is calculated, and the calculation formula is: ; in, represents the model effectiveness score, Represents the inverter output power in the current time period, Represents the output current in the current time period, Represents the current power factor, Represents the current ambient light intensity. Represents the current inverter temperature, represents the current operating load of the cooling, Represents the load of the inverter; Based on the mode performance score, combined with output stability, power factor fluctuation and temperature change trend, a mode performance analysis result is obtained.

[0011] Preferably, the steps of obtaining the adjusted sensor configuration are: According to the results of the model performance analysis, the new data collection frequency is calculated using the following formula: ; in, represents the new data collection frequency, represents the model effectiveness score, Represents the current ambient temperature. Represents the current ambient light intensity. Represents the output current change rate recorded by the sensor during the current time period. Represents the output power fluctuation amplitude of the inverter, Represents the current power factor; Based on the new data collection frequency, the data collection interval of the Hall sensor is adjusted to establish an adjusted sensor configuration.

[0012] Preferably, the steps for obtaining the system evaluation results are: Based on the adjusted sensor configuration, real-time data of the inverter output and the grid input are acquired to form a record of the interaction status between the inverter and the grid; According to the interactive state record between the inverter and the power grid, the stability of power transmission is evaluated, and the reverse flow situation is determined in combination with the power flow direction to form an anti-reverse flow performance evaluation result; Based on the anti-reverse flow efficiency evaluation results, the power flow direction and fluctuation amplitude under different load conditions are analyzed to establish system evaluation results.

[0013] Compared with the prior art, the advantages and positive effects of the present invention are: In the present invention, a Hall sensor is used to obtain the voltage, current, and frequency data of the power grid and the inverter, and the reverse flow risk is calculated in combination with the power balance state, so that data acquisition can reflect the instantaneous power flow and reduce the monitoring blind area caused by the fixed acquisition interval. Based on the analysis results of the power flow direction, the output power threshold is dynamically adjusted so that the inverter can respond quickly when the power feedback fluctuates, avoiding the imbalance of power feedback caused by unreasonable threshold setting. The inverter working mode is adjusted in combination with the ambient temperature and light intensity to make the power output under different environmental conditions more stable and avoid the reduction in energy efficiency caused by temperature and light changes. Through real-time data analysis of the operating performance under different load conditions, the optimized working mode can match the current power demand and enhance the adaptability to sudden power changes. Adjusting the data acquisition frequency of the sensor can adapt to the data update requirements under different load states, ensure data integrity under high dynamic changes, and reduce the calculation burden during low power changes, thereby improving calculation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the steps of the present invention. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0016] See also Figure 1 The present invention provides a technical solution, a photovoltaic micro-inverter anti-backflow monitoring method, comprising the following steps: The real-time data between the inverter and the power grid is collected through the Hall sensor. The real-time data includes voltage, current and frequency. The current power balance state is calculated based on the real-time data to generate the real-time power state. Based on the real-time power state, it is detected whether there is a potential reverse flow risk, and the output power threshold of the inverter is dynamically adjusted to obtain the adjusted output power threshold. Based on the adjusted output power threshold, the output power of the inverter is monitored to generate monitoring results; according to the monitoring results, the working mode of the inverter is adjusted in combination with the ambient temperature and the ambient light intensity to obtain an optimized working mode; Compare the optimized working mode with the operating data, analyze the performance under different environmental conditions, and generate the mode performance analysis results; according to the mode performance analysis results, adjust the data collection frequency of the Hall sensor and establish the adjusted sensor configuration; Based on the adjusted sensor configuration, the anti-backflow performance between the inverter and the grid is re-evaluated to generate system evaluation results.

[0017] The steps to obtain the real-time power status are: Collect the instantaneous voltage, current and frequency data of the inverter output end and the grid input end respectively, store the collected instantaneous voltage value, current value and frequency value into the data buffer area, and obtain the real-time monitoring data set; Based on the real-time monitoring data set, the current power balance state is calculated using the following formula: ; in, Representative moments The electrical energy balance state, Representative moments The instantaneous voltage value of the inverter output terminal, Representative moments The instantaneous current value of the inverter output, Representative moments The phase angle between the inverter output and the grid input, Representative moments The impedance on the inverter side, Representative moments The impedance of the grid side, Representative moments Reactive power on the inverter side, Representative moments Active power on the inverter side, For decimal values, prevent the denominator from being zero; Based on the power balance status, the stability of current power transmission is judged and the real-time power status is generated.

[0018] Specifically, in the process of synchronously reading the instantaneous voltage, current and frequency data at the inverter output end and the grid input end, it is necessary to set a sampling period and perform multiple scans according to the period, and record the voltage amplitude and the corresponding current amplitude and frequency value at each moment in real time. The monitoring range of voltage can be determined to be between 0V and 380V, the monitoring range of current can be determined to be between 0A and 10A, and the monitoring range of frequency can be determined to be between 45Hz and 65Hz. During each scan, the three types of data acquired at the current time point will be retained in the cache area through the data storage method, and sorted in order according to the timestamp. For the sampling values ​​with abnormal fluctuations, they can be cross-compared with multiple sampling points before and after. When the voltage or current exceeds the limit, the marking operation will be performed according to the established reference standard and the comparison and correction will be performed later. After multiple rounds of scanning and recording, the voltage, current and frequency data on the same time axis can be integrated into corresponding record entries to form a real-time monitoring data structure to ensure that the subsequent steps can accurately obtain valid values ​​from the data structure, and finally obtain the real-time monitoring data set.

[0019] The benefit of the formula is that by combining multiple factors such as voltage, current, phase angle, impedance, and active and reactive power, it integrates multiple source electrical parameters for comprehensive calculation, thereby more finely characterizing the instantaneous energy balance between the inverter output and the grid input, which helps to capture more subtle energy flow differences in real-time scenarios.

[0020] The acquisition step is to determine the voltage monitoring data obtained at time The voltage value at the output of the inverter is combined with the stability interval obtained by multiple scans to calibrate the specific value. The specific value can be extracted from the instantaneous voltage sequence read. For example, in the running test environment, each sampling cycle is 1 second. After collecting 600 voltage data in total, the fluctuation value is compared according to the time sequence and stability judgment standard, and the part exceeding the reference fluctuation range (such as ±10V) is eliminated. Then the average value of the remaining data is used as the time sequence. The voltage value is finally obtained in a certain running scenario ; To obtain this voltage value, the acquisition sequence can be recorded as , remove the items whose absolute value of difference with the previous and next sampling points is greater than 10 one by one, and after removing 20 abnormal records, take the arithmetic average of the remaining 580 data to obtain a result of 220 and use this value as the time The voltage value.

[0021] The acquisition steps are to use the current sampling data on the same time axis, and obtain the time through multi-point correction and comparison. The current value of the monitored current is first compared with the pre-defined valid range (0A to 10A), and the data entries higher than 10A are directly marked and moved to the abnormal statistics. The remaining current value is corrected by linear interpolation due to the fluctuation caused by high-frequency noise. The arithmetic average of all the corrected entries can be used to obtain a stable current value. Combined with the records measured on site, the final result is ; For the current data series ,After removing the abnormal items higher than 10A, the remaining data are interpolated and corrected according to the differences of adjacent sampling points, and the current value at that moment is determined by the average value of the corrected valid items.

[0022] The acquisition steps are as follows: using the phase data collected in the grid-connected system, first record the phase Phase with inverter output , and then find the difference between the two to get the time The phase angle In order to achieve the accuracy of quantification, phase comparison is performed within the frequency range collected per second, and abnormal values ​​with large phase jumps are eliminated. For example, 600 phase measurement values ​​are obtained within 600 consecutive seconds. Assuming that 30 of them have jumps greater than 10 degrees due to device jitter or interference, they are all removed. After averaging the remaining 570 values, , remember; this value comes from the measurement record, such as , move the records with absolute difference greater than 10 degrees into the abnormal list, and take the arithmetic average of the rest.

[0023] The acquisition steps are as follows: the impedance value is obtained according to the resistance measurement process of the electrical circuit at the inverter end, the impedance values ​​measured by the line segments at the inverter output end are operated in series and parallel, and then the impedance is corrected in combination with the actual power output during operation. For the convenience of quantification, a no-load measurement is performed when the system is put into use to obtain an initial value of about 7 ohms, and then a value of 11 ohms is obtained under a load current of 2A. Finally, the value is summarized by the segmented weighted method, and let are the weights under each measurement condition, according to , and then rounded to 10 according to the on-site working conditions.

[0024] The acquisition steps are as follows: perform the same resistance measurement and actual load measurement on the grid side, the method is similar to the inverter side, first measure 6 ohms at no load, and then measure 9 ohms when the line active power maintains 200W output, and also use the segmented weighted method to make ,final , and round up the actual nominal value to get 8.

[0025] The acquisition steps are as follows: the reactive power measurement value of the inverter side within the specified sampling period is obtained by recording the reactive power measurement value provided by the electrical monitoring instrument, and the average value can be used as the time after multiple accumulations. Reactive power, for example, after running for 300 seconds, a set of reactive power data is obtained through instrument recording , each acquisition is performed under the same power factor condition, and all entries are added together and then divided by 300 to get a value of 100.

[0026] The acquisition steps are as follows: the active power data of the inverter side in the same time period is counted, and the power count value is accumulated and averaged. For example, in a certain operation, the current output is 2A, the corresponding voltage is 220V, and the meter shows that the output power is about 200. At the same time, it runs stably for a period of time. Select the 300-second active power monitoring sequence , calculate the average value.

[0027] The steps to obtain is to take a very small value of 0.001.

[0028] Calculation process: The first step is to calculate the denominator , first ask , and then calculate , then 1 plus the value is , and then take the square root of 2.5625 to get a result of 1.601.

[0029] The second step is to calculate the numerator ,Right now , , so the numerator is approximately .

[0030] The third step is to divide the numerator by the denominator and get .

[0031] Step 4: Calculate ,Right now .

[0032] Step 5: Add the two together ,then .

[0033] The result shows that the instantaneous energy balance value at the current moment is 271.217. When the value falls within the balance threshold range set by the system (for example, 200 to 300), it can be determined that the inverter output and the grid input are in a relatively stable energy transmission state at this moment. If the subsequent monitoring shows that the value is lower than 200 or higher than 300, it means that there is fluctuation in energy transmission at the corresponding moment, and further analysis or adjustment should be made based on the specific reasons.

[0034] After obtaining the instantaneous energy balance result in the previous step, it is necessary to compare the current value with the threshold interval with reference to the established stable interval threshold, so as to identify the state of electric energy transmission. At this time, the previously obtained balance value can be compared with the lower and upper limits of the reference interval item by item. If the value is higher than the upper limit, it is marked as a fluctuation state item. If the value is lower than the lower limit, it is classified as a weak transmission state item. In addition, the voltage and current data in the same time period should be collected and cross-checked to determine the continuity of energy distribution. All records in the stable interval are uniformly placed in the data list of the electric energy stable interval, and then sorted in time series to identify whether there are value jumps or repeated deviations in adjacent time periods. By searching whether these jump segments exceed a certain number of empirical thresholds and recording them in a special statistical table, the statistical table can include items such as cumulative jump frequency and jump period. Records whose jump frequency reaches the reference value range should be classified separately and subsequently analyzed jointly with other moments. After these processes are completed, all records can be rearranged and summarized in chronological order to generate real-time electric energy status.

[0035] The steps for obtaining the adjusted output power threshold are: According to the real-time power status, the potential reverse flow risk score is calculated using the following formula: ; in, represents the potential backflow risk score, represents the instantaneous power at the inverter output, represents the instantaneous power at the grid input, Represents the power response time on the inverter side, represents the power response time on the grid side, represents the equivalent capacitance on the inverter side, represents the equivalent inductance on the grid side, represents the equivalent impedance on the inverter side, Represents the equivalent impedance on the grid side; According to the potential reverse flow risk score, it is determined whether to adjust the output power threshold of the inverter to obtain the adjusted output power threshold.

[0036] Specifically, the benefit of the formula is that by integrating multiple factors such as instantaneous power, response time, capacitance, inductance, and impedance on the inverter and grid sides, the system can take into account the impact of different dynamic links when scoring the reverse flow risk, thereby more accurately evaluating potential reverse flow conditions.

[0037] The acquisition steps are as follows: in a fully configured photovoltaic micro-inverter system, a real-time power monitoring instrument is used to record the power at the inverter output end, and an instantaneous output power reading is obtained every 1 second to ensure that a sufficient number of sample data can be summarized under a stable power supply state. In order to obtain numerical accuracy, it is necessary to check the grid fluctuations in advance and eliminate the moments when the voltage is too high or too low, and then perform consistency verification on the remaining data to obtain reliable power data; in order to quantify this parameter, the inverter can be operated continuously for 300 seconds in a constant irradiance environment, and the power values ​​of all sampling points during this period are recorded. After superposition and elimination of abnormal values, the average value is selected as For example, in a system with a single-phase output power of 500W, the monitoring instrument measured 270 valid collection items during this period, and the values ​​were mainly concentrated between 240W and 260W. The final comprehensive selected average value was 250W.

[0038] The acquisition steps are as follows: continuous collection is carried out according to the actual power detection device at the input end of the power grid. First, a power sensor is installed on the same transmission circuit connected to the inverter to record the power value of the power grid input per second. The record will be synchronized with the inverter side in terms of timing. In order to prevent data jumps caused by sudden changes in external load, it is necessary to compare the time of sudden increase or decrease according to the timestamp after the collection is completed, and move these abnormal data to the troubleshooting list, and then use the remaining record entries to take the average value to obtain a value that can represent the current load level and grid-connected situation; for example, in the collection process that also lasts 300 seconds, after eliminating the jump values ​​higher than 350W or lower than 100W, the power entries in the remaining normal range are accumulated and averaged to obtain a result of 300W.

[0039] The acquisition steps are as follows: to obtain the duration parameter through the power response test process of the inverter, it is necessary to issue a quick adjustment command to the inverter in a stable lighting environment in advance, and record the time from the issuance of the command to the power at the inverter output reaching the target value. This process can perform multiple rounds of tests at the same load level to offset the impact of the randomness of the single measurement environment. When the obtained multiple rounds of time-consuming values ​​converge to a certain area, the average value of the area is confirmed as the power response time; for example, through 6 independent measurements, under the condition that the interference is as fixed as possible, the recorded time consumption is 0.032s, 0.028s, 0.035s, 0.031s, 0.029s and 0.034s respectively. After removing the abnormal outliers, the average is 0.03s, and this value is used as .

[0040] The acquisition steps are as follows: perform power response time detection on the grid side. The response time refers to the time it takes for the system to reach a new balanced output level when the grid receives a certain power change demand. With the help of special monitoring equipment, perform multiple rounds of pressurization or unloading operations within the same range and record the power change rate. After centralized analysis, obtain an average response time. If 0.055s, 0.048s, 0.052s, 0.047s and 0.056s are obtained after 5 tests, the average value of about 0.05s is calculated, and 0.05s is used as .

[0041] The acquisition steps are as follows: it is determined by the nominal value of the main energy storage capacitor in the internal circuit of the inverter and the measured correction value. It is necessary to measure its capacitive reactance characteristics under different load conditions through a tester during the operation of the inverter, so as to infer the true equivalent value of the capacitor. Typically, a measurement is performed once in each of the two states of full-load power output and half-load power output, and the capacitive reactance parameters are obtained respectively. The capacitive reactance is converted into farad units through a predetermined calculation formula, and then a final equivalent capacitance value is summarized in a weighted manner under the two working conditions; in a photovoltaic micro-inverter with a rated power of 500W, after measurement and conversion, .

[0042] The acquisition steps are as follows: test the equivalent inductance value on the grid side. The inductive reactance can be measured on the wiring port and the value can be converted into Henry units. The specific process is to apply a voltage signal of a certain frequency to the grid line, measure the voltage drop and current formed by the inductance, and thus calculate the equivalent inductive reactance, and then convert it into the inductance value based on the relationship between the inductive reactance and the frequency; in the actual process, in order to maintain accuracy under 50Hz working conditions, it is necessary to measure multiple times and take the average, and finally get .

[0043] The acquisition steps are as follows: through the previously recorded inverter side impedance data and the impedance measurement sequence obtained by the detection instrument, the parallel and series impedances of the output line and internal components are comprehensively calculated to obtain a total impedance value including active and reactive components. After the unit conversion and segment calculation are completed, the overall amplitude is taken as the equivalent impedance. Assuming that the system is 5 The calculated value needs to meet the test conditions. The specific method is to convert the 3.8 obtained by independent measurement into , 5.1 , 4.7 The data are averaged according to the test method number and appropriately corrected to the maximum load condition, and then the final result is 5 As .

[0044] The acquisition steps are to perform similar multiple rounds of impedance measurement on the line connected to the power grid. The measurement process also needs to consider factors such as line length, conductor material and rated load, introduce the voltage and current data recorded throughout the process, and then calculate the sum of active and reactive components in segments to obtain the amplitude of the total line impedance.

[0045] Calculation process: Step 1: Calculation ,Right now .

[0046] Step 2: Ask ,Then ,after , and then take the square root to get 1.166.

[0047] Step 3: Divide the result of the first step by the result of the second step, that is .

[0048] Step 4: Calculation , and then calculate ,then ,then .

[0049] Step 5: Add the two results together ,get .

[0050] The result shows that the current potential reverse flow risk score is about 42.8672. The indicator corresponding to this step can be used to quantify the degree of reverse flow risk during the grid connection process. The higher the number, the more obvious the reverse flow threat is under the current operating state. For example, when When it exceeds 40, it can be considered that the potential backflow pressure is large. A value between 20 and 30 is considered to be within the controllable range. This score can be used in conjunction with subsequent steps to determine whether the inverter output power threshold needs to be further adjusted.

[0051] According to the potential reflux risk score obtained previously In the process of determining whether to adjust the inverter output power threshold, the score needs to be compared with the established score threshold list. The score threshold list lists several value ranges including 20 to 30, 30 to 40, and above 40, and allocates different processing suggestions accordingly. When the value of falls into any value segment, the corresponding processing strategy can be retrieved, and then a comprehensive comparison is made in combination with the current stable output data of the inverter and the power fluctuation information of the previous period. In order to make the power threshold setting more practical, it is necessary to read the inverter power adjustment information for the overload warning scenario in the historical monitoring, and compare the output power change level and response time difference of the previous period at the current moment. If the scoring segment and the fluctuation of the previous period both point to the risk of excessive output, the inverter power threshold of the next step can be fine-tuned and quantified downward. For this purpose, an adjustable parameter sequence will be set in the system, such as setting the adjustment step size to 5W or 10W and matching it with the scoring segment one by one. After that, each parameter will be mapped to the specific inverter output port, and the possible over-temperature risk and grid-connected instability factors will be recalculated. The comparison is further subdivided by supplementing the temperature metering data and the voltage and current change rate, so as to clarify the optimal threshold setting range. Finally, the output power threshold obtained after adjustment will be incorporated into the system configuration and called in the grid-connected detection process of the subsequent period.

[0052] The steps to obtain monitoring results are: Based on the adjusted output power threshold, the real-time power data of the inverter output end is called to calculate the deviation between the current output power and the adjusted output power threshold, and the data is divided into intervals after being arranged in chronological order to form power deviation trend data; According to the power deviation trend data, the power fluctuation range in each interval is calculated, and the classification standard is set according to the fluctuation range. The intervals are divided into stable, fluctuating and abnormal to form the monitoring results.

[0053] Specifically, based on the adjusted output power threshold obtained above, the current output power value per second is first extracted from the real-time monitoring record of the inverter and arranged in chronological order. Then, according to the reference standard compiled in advance for the characteristics of the inverter output, these instantaneous power readings are compared with the output power threshold obtained above, and the power difference at each moment is recorded and stored in a power difference sequence. In order to accurately divide the difference interval, it is necessary to first perform a range confirmation on the power difference sequence, for example, compare the difference between 0W and 50W to determine whether it is within an acceptable small deviation range, compare it with 50W to 100W to determine whether there is an obvious power increase or decrease, and compare it with the power difference sequence. The interval greater than 100W is used to identify sudden significant deviations. The same interval comparison is performed for each power difference value, and the corresponding timestamp and belonging interval are recorded after the matching is completed. In order to avoid the interval division being biased towards a certain extreme case, it is also necessary to establish multiple classification thresholds in the reference standard and state the basis for their setting. For example, in actual testing, 300 seconds of historical power collection records were used to calculate the average deviation of 30W, and 50W was established as the main monitoring threshold based on this. If it exceeds this value, it is considered worthy of separate attention. If it exceeds 100W, it can be determined as a large deviation. Through this multi-level comparison process based on threshold setting, the intervals to which the difference belongs are rearranged in chronological order to generate complete power deviation trend data.

[0054] According to the power deviation trend data formed above, the fluctuation amplitude of the accumulated power value in each interval needs to be analyzed. First, the interval records are read one by one and the adjacent records are differentially calculated based on the order of the actual collection time, so as to obtain the power fluctuation value within each interval, and then compared one by one in combination with the pre-classification standard for the fluctuation amplitude. This classification standard often includes three range segments. For example, the fluctuation amplitude between 0W and 20W can be regarded as a stable state, the fluctuation amplitude between 20W and 70W can be regarded as a fluctuating state, and if it reaches 70W or more, it is determined to be an abnormal state. The division of these value intervals is usually calculated by consulting the inverter output power history data for 600 seconds or even longer. For example, when continuously monitoring an inverter with a peak output of 300W, it is found that most of its normal fluctuation amplitudes are within 30W. Therefore, 20W is taken as the dividing line between stability and fluctuation, and then 70W is confirmed as the dividing line between fluctuation and abnormality in subsequent observations. After completing the one-to-one comparison of the interval fluctuation values, all records are summarized and three subsets of stability, fluctuation and abnormality are obtained at the end of classification, and finally the monitoring results are formed.

[0055] The steps to obtain the optimized working mode are: According to the monitoring results, the current ambient temperature and ambient light intensity values ​​are obtained, and the current working mode parameters of the inverter are extracted, including output power, working frequency and heat dissipation load level, to form an environment and inverter working status data set; Based on the environment and inverter working status data set, the working mode adjustment index is calculated using the following formula: ; in, Represents the working mode adjustment index, Represents the current ambient temperature. Represents the nominal operating temperature of the inverter, represents the instantaneous load level of the inverter heat dissipation, Represents the maximum heat dissipation capacity of the inverter. Represents the current ambient light intensity. Represents the current inverter output power, represents the power stability parameter on the inverter side, Represents the power fluctuation amplitude on the inverter side; Based on the working mode adjustment index, the adaptability of the current inverter working mode is analyzed, the impact of different working parameters on the inverter power output and heat dissipation load is evaluated, the output power and working frequency are set, and the optimized working mode is obtained.

[0056] Specifically, according to the recorded content of the previous monitoring results, first obtain the current ambient temperature and ambient light intensity values ​​on the same time axis, and on this basis extract the working mode parameters used in the current operation stage of the inverter. These parameters include output power, operating frequency and heat dissipation load level. In order to ensure the comparability of data collection, it is necessary to compare the ambient temperature and light intensity item by item in the established timestamp order. The comparison range can be set to the temperature range of 0℃ to 80℃ and the light intensity range of 0 to 1200W / ㎡. After comparing one by one, mark the temperature and light data that meet the range, and then compare the inverter output power, operating frequency and heat dissipation load level, and extract the corresponding values ​​at each moment in the actual operation period. If a record with a temperature higher than 80℃ or a light intensity exceeding 1200W / ㎡ is encountered, such records will be marked separately and subsequently handed over to The fault inspection link is used to identify the fault. Next, the four types of monitoring data are merged to form a time-related numerical group, in which the temperature index and light index can be used to match the output power and heat dissipation load level at the corresponding time. The same matching steps are also performed on the operating frequency value. If the temperature is lower than 10°C, the statistical trend of the sub-zero environment will be compared and the heat dissipation situation of the time period will be recorded. If the heat dissipation load exceeds the specified threshold, the temperature level and light value of the previous sampling data in the time period will continue to be retrieved to determine whether the change of the heat dissipation load is stable. After these interlocking comparison actions are completed, all record entries need to be integrated and numbered uniformly with time as the key sequence. Finally, the ambient temperature, light intensity, and working mode parameters corresponding to these numbers are stored one by one as the environment and inverter working status data set.

[0057] The benefit of the formula is that by incorporating multiple factors such as ambient temperature difference, inverter's current heat dissipation load ratio, ambient light intensity and output power, power stability and fluctuation range into a comprehensive calculation framework, it can more comprehensively measure the adaptability of the inverter's working mode under specific environmental conditions.

[0058] The acquisition steps are as follows: use the temperature measurement equipment installed at the operation site for real-time collection. This equipment scans the ambient temperature and records the value every second. After the collection sequence is synchronized, the records exceeding 80℃ or below -10℃ are compared and marked separately, and then the remaining valid records are averaged to obtain the temperature value at the current moment. In the actual site, a large number of temperature sampling points can be obtained in 300 seconds of continuous monitoring. For example, in an environment with strong light and general external ventilation conditions, most temperature values ​​are between 30℃ and 40℃. If the average value of 35℃ is obtained at this moment, this 35℃ is used as the average value. For subsequent operations.

[0059] The steps to obtain it are to refer to the nominal operating temperature listed in the inverter manufacturer or system configuration file. This value is usually determined during product design, and in a specific usage scenario, a more suitable design temperature may be determined through multiple proofing tests. For example, the nominal operating temperature of some photovoltaic micro-inverters is about 25°C. To ensure the accuracy of the value, it is necessary to adjust the external environment under laboratory conditions and monitor the temperature rise of the inverter components. After obtaining multiple rounds of test results, the average value is calculated. For example, for a micro-inverter with a power capacity of 500W, the temperature of its casing and internal key components is collected during 10 hours of continuous operation and the average value is calculated to obtain a nominal value of 25°C, and 25°C is used as Write it down.

[0060] The acquisition steps are as follows: by measuring the instantaneous occupancy of the inverter on the cooling system at the current moment, a cooling sensor point needs to be reserved inside the inverter to continuously read the speed, voltage and current of the cooling fan, and then combine the fan power, heat sink temperature and other indicators to comprehensively quantify the cooling load. To accurately represent the load level, at least 300 seconds of monitoring records can be selected after the system runs stably, and the fan speed and power consumption are compared one by one. These records are put in the same table, and then the average power of the value is counted and mapped to a range of 0 to 5. The range division is based on the equipment design. For example, 0 represents fan stop and 5 represents fan maximum power operation. After actual measurement at a certain moment, it is obtained .

[0061] The steps to obtain the maximum heat dissipation capacity setting value of the inverter equipment are as follows: the manufacturer usually gives a limit heat dissipation value during the thermal design evaluation before leaving the factory, and then converts it into a range of 0 to 5 or 0 to 10. The value will be listed in the factory documents and can be tested and verified by laboratory means. For example, for an inverter with a cooling fan rated power of 2W, if the fan power reaches 2W when the full power consumption is dissipated and the heat sink temperature is maintained at a normal level, the full-scale heat dissipation level corresponding to this state can be recorded as 5. If the user measures and finds that the speed value is equal to the set limit at the highest heat dissipation load, it can be attributed to .

[0062] The acquisition steps are as follows: use a light intensity monitoring device to obtain the ambient light intensity. The device will output the detected solar irradiance value in W / ㎡, collect it once per second and record it in the light sequence. After screening out abnormal entries with values ​​greater than 1300W / ㎡ or less than 0, the current light intensity can be obtained by averaging the valid data. Continuous observations can be carried out in advance in the field environment. If the light intensity measured in a certain test interval is mostly distributed between 700W / ㎡ and 900W / ㎡, the current sequence average is 800W / ㎡.

[0063] The acquisition steps are to collect and verify the inverter output power. First, install a power meter at the output end, set a sampling period of 1 second, and continuously record the current power value of the inverter. Each record must be cross-validated with the existing voltage and current measurement values. After filtering out records that deviate too much from the theoretical power, perform an average operation on the remaining sampled items to obtain the output power value applicable to that moment. In the demonstration scenario, a certain inverter stably outputs an actual power of about 180W, which can be determined. .

[0064] The acquisition steps are as follows: refers to the power stability parameter on the inverter side, which needs to be calculated using the previous power deviation trend data and fluctuation amplitude classification results. The minimum, maximum, average and median power fluctuations within a certain sampling period are comprehensively counted, and then these statistics are reduced to a stability indicator through a quantitative formula. For example, the value is obtained by weighting the fluctuation standard deviation and the maximum deviation. If the calculation of a 300-second power record shows that the inverter power standard deviation is 5W and the maximum deviation is 20W, a ratio can be set. and ,make , and the final rounded value is 13.

[0065] The acquisition steps are as follows: the power fluctuation amplitude parameter on the inverter side is usually aggregated and counted in combination with the fluctuation interval classification formed by the previous monitoring system. The maximum deviation and the minimum deviation are extracted in each fluctuation interval, and the average value is calculated after adding them up to represent the fluctuation amplitude scale. Assuming that there are multiple significant fluctuations in an operation stage, and each fluctuation range is between 25W and 35W after statistics, the central value of 30W is selected as In actual implementation, the fluctuation range can also be subdivided, for example, data can be collected progressively at 5W intervals, and then all of them can be merged and averaged to ensure that more accurate values ​​can be obtained when the amount of data collected is sufficient.

[0066] Substituting the formula into the current working mode adjustment index, the value is 22777.48. A high value means that the inverter is in a high-load operation state when it outputs 180W power and has a certain heat dissipation load under the environment of 35℃ and 800W / ㎡. If the threshold value defined by the system is set, once If it exceeds 10,000, it means that the heat dissipation and power configuration need to be further optimized. If it is in the range of 5,000 to 10,000, it means medium load. If it is below 500, it means light load. The manager can reduce or maintain the output power and operating frequency accordingly to obtain the optimized working mode mentioned in the subsequent steps.

[0067] Based on the working mode adjustment index obtained earlier, first compare the measured data of output power, working frequency and heat dissipation load one by one in the collected historical working parameters of the inverter, and compare these measured data with the inverter performance indicators under different ambient temperatures and light intensities one by one. By crossing the change curve of each working parameter under the current environmental conditions with the previously recorded reference interval, record the fluctuation range of each parameter in the reference interval and the response during the high-load period. If a certain working parameter exceeds the set threshold for multiple consecutive moments, trace it back against the source of the threshold. For example, an upper limit of the interval is obtained from the average value extracted multiple times during the test period. If the current parameter value is monitored to exceed the upper limit by a large margin, it is marked as a potential abnormality in the comparison, and then all the marked results are concentrated in a summary index to perform a correlation test on the correlation between the heat dissipation load and the power output. The output power is arranged in grades according to the ambient light level in different time periods, and the results are summarized. A distribution chart of the heat dissipation load under each output level during actual operation is drawn to locate the corresponding relationship between the heat dissipation load and the power. For periods of time when the heat dissipation load is high but the output power is relatively low, the working mode will be fine-tuned in subsequent steps. The above process can fully demonstrate the mutual influence between heat dissipation, frequency and power. If there are multiple high frequencies and high heat dissipation loads coexisting in certain periods, it is necessary to mark the temperature and light records corresponding to the situation in the table, and further check whether there are electrical fluctuations or power factor deviations, so as to obtain new setting suggestions for the output power and operating frequency. Then, according to the evaluation results, the power setting value and the frequency setting value are gradually lowered or increased during the execution process. When there are multiple optional schemes, they can be compared side by side with the ambient temperature data obtained previously, and the power trend and heat dissipation situation of each scheme under high or low temperature conditions can be quantified, and finally an output power and operating frequency combination, that is, the optimized working mode, is selected.

[0068] The steps to obtain the results of model effectiveness analysis are as follows: According to the optimized working mode, the mode performance score is calculated, and the calculation formula is: ; in, represents the model effectiveness score, Represents the inverter output power in the current time period, Represents the output current in the current time period, Represents the current power factor, Represents the current ambient light intensity. Represents the current inverter temperature, represents the current operating load of the cooling, Represents the load of the inverter; Based on the mode performance score, combined with output stability, power factor fluctuation and temperature change trend, the mode performance analysis results are obtained.

[0069] Specifically, the formula is beneficial in that, by comprehensively comparing the output power and output current of the inverter in the current time period, as well as the power factor and ambient light intensity, the temperature, heat dissipation load and inverter load factors are incorporated into the denominator structure, thereby achieving an accurate quantitative evaluation of the actual performance of the working mode.

[0070] The acquisition steps are as follows: take the actual output power of the inverter in the current time period. It is necessary to install a power metering device at the output end of the inverter, record the power with a sampling period of one second, and verify the recorded data with the voltage and current monitoring items. For abnormal data that exceeds the nominal power limit, remove it, and then perform an average operation on the remaining recorded values ​​in the same time period. For example, the power values ​​measured in the 300-second monitoring are mainly distributed between 180W and 200W. Finally, 190W is obtained as the average output power of the time period and assigned to .

[0071] The acquisition steps are to directly read the output current of the current time period and match it with the above-mentioned output power value. The current value is collected once a second through the current sampler equipped at the output end of the inverter, and the voltage and power data at the sampling time are synchronously compared to ensure data consistency. If it is detected that the current sampling value obviously exceeds the electrical rated range, it will be marked and excluded separately, and then the remaining valid samples will be averaged to obtain the current value of the current period. For example, after removing the abnormal items that are too high or too low in the 300-second monitoring record, the average current of 2.8A is calculated, and the value can be determined as .

[0072] The steps to obtain it are as follows: refers to the current power factor. When the inverter is connected to the grid, the ratio of active power to apparent power on the inverter side needs to be calculated. It can be obtained indirectly by relying on a power factor measuring instrument or by recording reactive power and active power. Then the measured power factor is compared with the voltage and current in the same time period to confirm the authenticity of the data and obtain the most representative average value of the period. For example, in a measurement period of 300 seconds, reactive power and active power are recorded, apparent power is calculated first, and then the power factor is obtained by dividing the active power by the apparent power. In order to avoid errors caused by sudden fluctuations at extreme individual moments, the data at most moments can be taken for statistical averaging. If 0.95 is finally obtained, 0.95 can be recorded as .

[0073] The acquisition steps are as follows: obtain the ambient light intensity through the light monitoring device with the same frequency as above, combine it with the second-level record in the current time period, remove the abnormal values ​​in the light data that exceed 1300W / ㎡ or are lower than 0, and then average the remaining valid entries. Assuming that the final light intensity of this period is 800W / ㎡, 800 is used as The numerical value of .

[0074] The acquisition steps are as follows: refers to the current inverter temperature. It is necessary to place a temperature sensor inside the inverter or on the surface of the casing and record it continuously. The temperature values ​​per second are collected in sequence. The measurement records that are higher than the inverter protection limit or significantly lower than the normal temperature are placed separately in the abnormal sequence. The rest of the data within the normal range are aggregated and averaged to obtain the temperature value of the period. For example, if the average temperature result of a certain measurement is 45°C, 45 is recorded as .

[0075] The steps for obtaining the current operating load of heat dissipation are as follows: for the current operating load of heat dissipation, it is necessary to install power and speed monitoring on the built-in heat dissipation unit of the inverter, and to perform quantitative calculations based on multiple information such as the heat dissipation fan power and the heat pipe temperature transfer efficiency. To make the results easy to compare, the heat dissipation load level can be represented by a range of 0 to 5 or 0 to 10. After mapping and counting the fan speed and the actual temperature difference of the heat sink, if the fan power is at a mid-range level and the temperature difference is also medium after multiple measurements, the quantified value of the heat dissipation load during this period can be recorded as 3, and then 3 is assigned to .

[0076] The steps of obtaining are as follows: for the load of the inverter, it is necessary to observe the ratio of the power output to the rated power when the inverter is running, or to perform real-time statistics on the load current of the internal components and map it to the range of 0 to 10. If the on-site measurement finds that the current load is about 30% higher than usual, and it is confirmed based on multiple rounds of records that it continues to be at a high level, then a value of 7 can be assigned in the quantitative mapping, and let .

[0077] Substituting the formula into the calculation, the current mode efficiency score is 49.46. The high score indicates that under the conditions of 190W output power, 2.8A output current, power factor 0.95 and 800W / ㎡ lighting environment, the operating status when the inverter temperature is 45℃, the heat dissipation load is 3, and the overall load level is 7, there are still certain differences and inconsistencies. If this score exceeds 40, a comprehensive comparison can be made in the subsequent steps based on the output stability, power factor fluctuation and temperature change trend, and the mode efficiency analysis results can be obtained after summary.

[0078] Based on the previously obtained mode efficiency score, the output stability data, power factor fluctuation data and temperature change data recorded in the same time period are compared and compared with the mode efficiency score value one by one. The output stability data can refer to the fluctuation range defined previously to determine whether it is a slight fluctuation or a significant fluctuation, and the degree of deviation of the power factor in the same time period is included in a numerical sequence for viewing in conjunction with the current score value. The observation items of the inverter at different temperature levels are then arranged in chronological order and the heat dissipation records corresponding to each temperature point are marked. The heat dissipation load is compared with the heat dissipation status in the corresponding record to see if it is too high or too low. If several comparisons show that the heat dissipation load is high but the mode efficiency score exceeds the specified threshold, the setting method of the threshold in the production test phase can be extracted. For example, the 60-point level previously calculated through multiple months of data is used as a key value. If the mode efficiency score is A score higher than 60 means that there is a greater power deviation or temperature pressure under the corresponding conditions. Combined with the fluctuation record, it is also possible to retrieve whether the power factor fluctuation has exceeded the pre-set range, such as the power factor drops from 0.95 to below 0.85. If it exceeds this range, the data of this time period will be specially marked. After marking, the temperature rise and fall or heat dissipation power distribution of this period will be traced back and archived for comparison. If it is found that the temperature shows a continuous upward trend and the output stability is weakening, it will be recorded as a potential factor that may lead to subsequent abnormalities. These potential factors are classified as general problems or states that require further adjustment. Subsequently, the mode performance analysis results are obtained based on the superposition of fluctuation classification and scoring range. By arranging the various values ​​​​in chronological order in the final table and querying them with the score as the index, the interactive relationship between temperature, power factor and heat dissipation load in different working modes can be screened out, and these analysis results are recorded in the result list.

[0079] The steps to obtain the adjusted sensor configuration are: According to the results of the model effectiveness analysis, the new data collection frequency is calculated using the following formula: ; in, represents the new data collection frequency, represents the model effectiveness score, Represents the current ambient temperature. Represents the current ambient light intensity. Represents the output current change rate recorded by the sensor during the current time period. Represents the output power fluctuation amplitude of the inverter, Represents the current power factor; Based on the new data collection frequency, the data collection interval of the Hall sensor is adjusted to establish an adjusted sensor configuration.

[0080] Specifically, the benefit of the formula is that by aggregating the elements such as mode performance score, ambient temperature, light intensity, current change rate, power fluctuation amplitude and power factor into a comprehensive indicator, it can more intuitively express the necessity of adjusting the data collection frequency under the current operating conditions, thereby taking into account the inverter output power fluctuation, external temperature and light environment and current changes at the sensor end.

[0081] The steps to obtain the model performance score are as follows: .

[0082] The acquisition steps are to use a dedicated temperature sensor to capture the current ambient temperature in real time, collect the temperature once a second, and compare it with the previous inverter power, current, etc. records at the same timestamp. If the temperature range in the field is between 0℃ and 80℃, first filter out abnormal readings less than 0℃ or greater than 80℃, then perform a consistency check on the remaining temperature entries and select their average value, which can be used as the current ambient temperature. For example, in a field monitoring, the temperature readings are mostly between 25℃ and 35℃. After removing the extreme values, the average is 30℃. If a certain operation needs to be quoted, it can be used. .

[0083] The steps to obtain it are: you need to install a light intensity detection device in advance, and use second-level sampling to obtain the light intensity at that moment, usually expressed in W / ㎡. To ensure the validity of the measurement data, records above 1300W / ㎡ or below 0 need to be marked as abnormal and removed, and the average of the remaining records can be used to obtain the current light intensity. For an outdoor photovoltaic area, all sampled values ​​can be aggregated and calculated for 300 consecutive seconds. If they are mainly distributed between 600W / ㎡ and 800W / ㎡, and the final statistics are 750W / ㎡, the value can be determined as .

[0084] The acquisition steps are as follows: the output current change rate recorded by the sensor needs to be counted in the current sampler at the inverter end, and the increase or decrease of the current value in adjacent sampling periods. The method is to collect the current value once per second, and then calculate the difference between the value and the value of the previous second, and then arrange all the differences in time series and calculate the average or a certain quantile to reflect the overall rate of current change. In order to avoid the influence of individual outliers, extreme readings that exceed the set range (for example, ±3A / s) can be further screened out. The remaining difference sequence is averaged. If a current change rate of 0.8A / s is finally obtained, the value is recorded as .

[0085] The steps to obtain the output power fluctuation amplitude of the inverter can refer to the previous classification results of the power deviation trend and calculate the average value of the fluctuation amplitude in the selected time window. For example: first make the difference between the maximum and minimum values ​​of the recorded output power sequence, and then combine other power deviations in the interval to calculate the overall average. For example, in a 300-second monitoring window, the power range is 180W to 220W, and the fluctuation amplitude is about 40W. If 40W is determined as the fluctuation amplitude of the current window after calculation, then .

[0086] The steps to obtain are as follows: to represent the current power factor, the ratio of active power to apparent power needs to be monitored when the inverter is connected to the grid, or it can be directly read out in real time by the power factor measurement device. Usually only acceptable records in the range of 0.8 to 1.0 are retained, and the rest are regarded as abnormal values. After a certain on-site statistics, if the power factor is finally obtained as 0.9, which is relatively stable, then this value is assigned .

[0087] Calculation process: Setting parameters: .

[0088] Substitute into the formula and calculate The result shows that the new data collection frequency is about 38571.36. The higher value means that under the conditions of the current mode performance score of 49.46, ambient temperature of 30℃, light of 750W / ㎡ and current change rate of 0.8A / s, the data collection of the sensor needs to be configured more intensively. For example, the result value unit can be interpreted as Hz and then further corrected to guide the number of samples per second. If the subsequent definition is The upper limit is set to 2000Hz. If it exceeds the upper limit, it will be configured according to 2000Hz. In this case, it can be judged that it is far beyond the upper limit of the threshold and the maximum sampling density needs to be implemented. If it is less than 500, it means that the sensor sampling requirement is relatively low, and the value can be adjusted based on the actual power consumption and accuracy requirements.

[0089] Based on the new data acquisition frequency, it is necessary to first read the upper and lower limits of the sampling density obtained previously in the system configuration to determine whether there is an over-sampling or under-sampling problem, and then compare the result value of 38571.36 with the sampling limit set by the system. For example, the maximum sampling frequency is limited to 2000Hz or 3000Hz. If the calculation result is greater than the limit value, it will be mapped to the maximum sampling frequency in the subsequent configuration and recorded in the sensor configuration plan. If the calculation result falls at a lower level, such as less than 500Hz, it is necessary to evaluate whether it will affect the fine capture of voltage and current data. At this time, this lower frequency value can be compared with the previously obtained A secondary comparison is performed on the power and current fluctuation data to check whether rapid mutations will be missed under this sampling frequency. Once it is confirmed that no key information will be lost, the new data collection interval and the scanning period of the Hall sensor can be updated to the system configuration, such as dividing 1 second into several equal parts for data collection. Then, in the actual operation stage, the resolution and noise of the sensor are further observed, and independent record entries are added for instantaneous jumps that occur in extreme cases, so that more real current fluctuation characteristics can be carried in the next round of sampling frequency calculation. After completing this series of comparisons and matches, the final sampling interval results are merged into the sensor configuration list.

[0090] The steps to obtain the system evaluation results are as follows: Based on the adjusted sensor configuration, real-time data of the inverter output and grid input are obtained to form a record of the interaction status between the inverter and the grid; According to the interactive status record between the inverter and the grid, the stability of power transmission is evaluated, and the reverse flow situation is judged in combination with the power flow direction to form the anti-reverse flow performance evaluation result; Based on the anti-reverse flow efficiency evaluation results, the power flow direction and fluctuation amplitude under different load conditions are analyzed, and the system evaluation results are established.

[0091] Specifically, based on the adjusted sensor configuration obtained above, the Hall sensor is first synchronized according to the set data acquisition frequency and electrical measurement range, and the instantaneous voltage and current at the inverter output and the grid input are compared in time sequence. In order to distinguish the corresponding relationship between the power supply side and the load side during the recording process, it is necessary to establish a unified time reference for the data records at the inverter output and the grid input, and mark the voltage, current and frequency values ​​collected every second with timestamps respectively. Then, they are merged in the order of timestamps and the entries with mismatched times are deleted. Records that exceed the predetermined range, such as voltages higher than 450V or lower than 0V, are marked, and records with currents exceeding 10A or less than 0A are also separately classified. These marked records will be retained in the abnormal pair According to the list, so as to carry out centralized inspection later, all normal records are numbered in sequence, and then the values ​​of the inverter output and the grid input under the corresponding number are packaged into a record, so that a merged data table containing voltage, current, frequency and timing information can be continuously generated. In order to further identify the rate of change in the interactive state, the difference between adjacent records is calculated, and the entries with a difference exceeding a certain threshold are reviewed. For example, the threshold is set according to the jump amplitude of 5V or 1A. If the voltage or current difference of any record exceeds the threshold, a warning mark is attached to the special floating fluctuation sequence. After the entire time scan is completed, the complete data sequence is summarized and the position index and difference information of all abnormal entries are attached.

[0092] According to the previously obtained records of the interaction status between the inverter and the grid, the fluctuation of power transmission needs to be checked one by one. First, the two main dimensions of voltage and current are extracted from the merged data table arranged according to the timestamp to perform active and reactive power calculations, and the results are compared with the actual grid-connected status at each moment to determine the energy flow from the load end to the grid end or the energy flow from the grid end to the load end. If there are multiple records in which the inverter outputs a power value greater than a preset threshold to the grid, for example, the preset threshold can be set to 100W through historical monitoring, then it is recorded in the mark as a possible reverse flow state. For all records marked as reverse flow states, the data of several seconds around them can be retrieved to check the voltage and current. The evolution trend of the difference is recorded and whether there are large fluctuations. For reactive power data, it is compared with the basic benchmark value range. For example, ±50Var is taken as the evaluation interval. After comparison with the actual monitoring data, it is determined whether it exceeds the interval. If it exceeds, it is listed as a sample to be observed. This information is summarized in an analysis list with the voltage and current curves. By comparing the active power and voltage and current phase angle positions at each moment, it is determined whether there is a persistent reverse flow or short-term reverse transmission. If the judgment conclusion shows that the reverse transmission continues for more than the specified time, it is included in the core sequence. The large current jumps in this core sequence are counted and summarized in the final current fluctuation item to meet the next step of comprehensive comparison requirements.

[0093] Based on the anti-reverse flow performance evaluation results obtained above, it is necessary to classify the power flow under different load conditions into grades, for example, define low load as 0W to 100W, medium load as 100W to 200W, and high load as above 200W, compare the voltage fluctuation information and reactive power amplitude in each interval, and then combine the continuous reverse flow or short-term reverse flow mark items recorded in the previous stage, and associate them with the operating time of the corresponding load interval. If the reverse flow mark still appears multiple times during the low load period and the duration exceeds the reference boundary, for example, the boundary is set to 30 seconds through historical analysis, it will be highlighted in the evaluation report. The fluctuation situation during the high load period needs to check the stability of the grid-connected voltage and grid-connected current. By comparing the statistically obtained voltage standard deviation and current standard deviation, it is determined whether it has entered an extreme fluctuation level. Then, the determination result is used for stratification, and the period with large fluctuations is divided into a high-risk interval and its corresponding power flow is recorded. If there is an obvious reverse current, it is marked as a high possibility of reverse flow. In this way, multiple comparison results in the entire record are merged into the final operating status chart.

Claims

1. A photovoltaic micro-inverter anti-backflow monitoring method, characterized in that: The following steps are involved: The Hall sensor collects real-time data between the inverter and the power grid, including voltage, current and frequency. The current power balance state is calculated based on the real-time data to generate real-time power state. Based on the real-time power state, detecting whether there is a potential reverse flow risk, dynamically adjusting the output power threshold of the inverter, and obtaining an adjusted output power threshold; Based on the adjusted output power threshold, monitor the output power of the inverter and generate a monitoring result; according to the monitoring result, in combination with the ambient temperature and the ambient light intensity, adjust the working mode of the inverter to obtain an optimized working mode; Comparing the optimized working mode with the operating data, analyzing the performance under different environmental conditions, and generating mode effectiveness analysis results; According to the pattern performance analysis result, adjusting the data acquisition frequency of the Hall sensor and establishing an adjusted sensor configuration; Based on the adjusted sensor configuration, the anti-reverse flow performance between the inverter and the grid is re-evaluated to generate a system evaluation result.

2. The photovoltaic micro-inverter anti-backflow monitoring method according to claim 1, characterized in that: The steps of acquiring the real-time power state are: Collect the instantaneous voltage, current and frequency data of the inverter output end and the grid input end respectively, store the collected instantaneous voltage value, current value and frequency value into the data buffer area, and obtain the real-time monitoring data set; Based on the real-time monitoring data set, the current power balance state is calculated using the following formula: ； in, Representative moments The electrical energy balance state, Representative moments The instantaneous voltage value of the inverter output terminal, Representative moments The instantaneous current value of the inverter output, Representative moments The phase angle between the inverter output and the grid input, Representative moments The impedance on the inverter side, Representative moments The impedance of the grid side, Representative moments Reactive power on the inverter side, Representative moments Active power on the inverter side, For decimal values, prevent the denominator from being zero; Based on the power balance state, the stability of current power transmission is determined and a real-time power state is generated.

3. The photovoltaic micro-inverter anti-backflow monitoring method according to claim 1, characterized in that: The steps for obtaining the adjusted output power threshold are: According to the real-time power state, the potential reverse flow risk score is calculated, and the calculation formula is: ； in, represents the potential reflux risk score, represents the instantaneous power at the inverter output, represents the instantaneous power at the grid input, Represents the power response time on the inverter side, represents the power response time on the grid side, represents the equivalent capacitance on the inverter side, represents the equivalent inductance on the grid side, represents the equivalent impedance on the inverter side, Represents the equivalent impedance on the grid side; According to the potential reverse flow risk score, it is determined whether to adjust the inverter output power threshold to obtain an adjusted output power threshold.

4. The photovoltaic micro-inverter anti-backflow monitoring method according to claim 1, characterized in that: The steps for obtaining the monitoring results are: Based on the adjusted output power threshold, real-time power data of the inverter output end is called, the deviation between the current output power and the adjusted output power threshold is calculated, and the data is divided into intervals after being arranged in chronological order to form power deviation trend data; According to the power deviation trend data, the power fluctuation amplitude in each interval is calculated, and the classification standard is set according to the fluctuation amplitude, and the interval is divided into stable, fluctuating and abnormal to form a monitoring result.

5. The photovoltaic micro-inverter backflow prevention monitoring method according to claim 1, characterized in that: The steps for obtaining the optimized working mode are: According to the monitoring results, the current ambient temperature value and the ambient light intensity value are obtained, and the current working mode parameters of the inverter are extracted, including output power, working frequency and heat dissipation load level, to form an environment and inverter working state data set; Based on the environment and inverter working state data set, the working mode adjustment index is calculated, and the calculation formula is: ； in, Represents the working mode adjustment index, Represents the current ambient temperature. Represents the nominal operating temperature of the inverter, represents the instantaneous load level of the inverter heat dissipation, Represents the maximum heat dissipation capacity of the inverter. Represents the current ambient light intensity. Represents the current inverter output power, represents the power stability parameter on the inverter side, Represents the power fluctuation amplitude on the inverter side; Based on the working mode adjustment index, the adaptability of the current inverter working mode is analyzed, the influence of different working parameters on the inverter power output and heat dissipation load is evaluated, the output power and the working frequency are set, and the optimized working mode is obtained.

6. The photovoltaic micro-inverter anti-backflow monitoring method according to claim 1, characterized in that: The steps for obtaining the model effectiveness analysis results are: According to the optimized working mode, the mode performance score is calculated, and the calculation formula is: ； in, represents the model effectiveness score, Represents the inverter output power in the current time period, Represents the output current in the current time period, Represents the current power factor, Represents the current ambient light intensity. Represents the current inverter temperature, represents the current operating load of the cooling, Represents the load of the inverter; Based on the mode performance score, combined with output stability, power factor fluctuation and temperature change trend, a mode performance analysis result is obtained.

7. The photovoltaic micro-inverter anti-backflow monitoring method according to claim 1, characterized in that: The steps of obtaining the adjusted sensor configuration are: According to the results of the model performance analysis, the new data collection frequency is calculated using the following formula: ； in, represents the new data collection frequency, represents the model effectiveness score, Represents the current ambient temperature. Represents the current ambient light intensity. Represents the output current change rate recorded by the sensor during the current time period. Represents the output power fluctuation amplitude of the inverter, Represents the current power factor; Based on the new data collection frequency, the data collection interval of the Hall sensor is adjusted to establish an adjusted sensor configuration.

8. The photovoltaic micro-inverter anti-backflow monitoring method according to claim 1, characterized in that: The steps for obtaining the system evaluation results are as follows: Based on the adjusted sensor configuration, real-time data of the inverter output and the grid input are acquired to form a record of the interaction status between the inverter and the grid; According to the interactive state record between the inverter and the power grid, the stability of power transmission is evaluated, and the reverse flow situation is determined in combination with the power flow direction to form an anti-reverse flow performance evaluation result; Based on the anti-reverse flow efficiency evaluation results, the power flow direction and fluctuation amplitude under different load conditions are analyzed to establish system evaluation results.

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