Power generation monitoring method and system for photovoltaic panel

Abstract

The invention relates to the technical field of photovoltaic power generation monitoring, in particular to a power generation monitoring method and system for a photovoltaic panel, and the method comprises the steps: collecting the electrical parameters and environmental parameters of the photovoltaic panel in real time, and determining a preliminary voltage adjustment step length according to the electrical parameters and equivalent impedance characteristics of the photovoltaic panel; according to the change amplitude, the change rate and the historical stability of the illumination intensity and the temperature at the current moment, an environment influence factor is constructed, the initial voltage regulation step length is subjected to nonlinear correction through the environment influence factor, and the self-adaptive constraint and relaxation regulation of the step length on the severe environment change are realized. And on the basis, carrying out multiple symmetric disturbance operations on the voltage at the current moment, judging the adjustment direction through power difference, and carrying out dynamic adjustment in combination with the step length until the maximum power point is determined. The method improves the accuracy, stability and response sensitivity of photovoltaic power generation monitoring in a complex environment.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation monitoring. Specifically, it relates to a power generation monitoring method and system for photovoltaic panels. Background Art

[0002] As an important part of the application of renewable energy, the power generation efficiency of a photovoltaic power generation system depends to a large extent on whether the operating state of the photovoltaic panel can always be close to the maximum power point. How to stably and efficiently achieve maximum power point tracking is the key to ensuring the power generation efficiency of the photovoltaic panel.

[0003] The conductance increment method is a typical maximum power point tracking method. Based on the power-voltage characteristic curve of the photovoltaic panel, this method determines the relative position between the current operating point and the maximum power point by comparing the relationship between the conductance increment and the instantaneous conductance, and decides the voltage adjustment direction accordingly. Then, iterative adjustment is performed according to the voltage adjustment direction and a preset fixed adjustment step size to gradually approach the maximum power point.

[0004] However, the fixed-step strategy has inherent defects: when the step size is large, the system is prone to overshoot and oscillation when approaching the maximum power point, resulting in energy fluctuations and a decrease in conversion efficiency; when the step size is small, the system response becomes slow, especially in dynamic environments such as drastic changes in light intensity, and the tracking ability is significantly insufficient, showing an obvious deviation from the maximum power point.

[0005] More critically, in the actual photovoltaic operating environment, the changes in light intensity and ambient temperature usually have an asynchronous and non-linear combined effect on the electrical characteristics of the photovoltaic panel. The rapid fluctuation of light intensity will cause a drastic change in current, while the slow rise in temperature will cause the maximum power point voltage to continuously shift. Traditional methods do not model such environmental factor changes and also lack the dynamic adaptation ability to the adjustment strategy, and cannot flexibly adjust the step size according to the intensity of environmental disturbances, thus limiting the stability and tracking accuracy of the system in complex operating scenarios.

[0006] Therefore, there is an urgent need for a maximum power point tracking method that can integrate environmental dynamic characteristics and has an adaptive adjustment ability to improve the power generation efficiency and the robustness of system operation in an environment with light and temperature fluctuations, so as to accurately monitor the power generation of the photovoltaic panel. Summary of the Invention

[0007] To solve the problems that the fixed step size in the traditional conductance increment method is difficult to balance speed and accuracy during the maximum power point tracking process and has weak environmental disturbance adaptability, the present invention proposes a power generation monitoring method and system for photovoltaic panels.

[0008] In a first aspect, the present invention provides a power generation monitoring method for a photovoltaic panel, including: Collect the voltage, current, temperature and light intensity of the photovoltaic panel in real time; Taking any moment as the current moment, according to the voltage, current and power values at the current moment and the previous moment, and combining with the equivalent impedance characteristics of the photovoltaic panel, determine the preliminary voltage adjustment step size, which is used to adjust the rate of tracking the maximum power point; According to the change amplitude, change rate and historical stability of the light intensity and temperature at the current moment respectively, determine the environmental impact factor at the current moment, and non-linearly correct the preliminary voltage adjustment step size through the environmental impact factor, so as to limit the step size amplitude when the environment changes violently and increase the step size amplitude when the environment changes stably, and obtain the corrected voltage adjustment step size; Based on the corrected voltage adjustment step size, perform multiple symmetric perturbation operations on the voltage at the current moment, judge the voltage adjustment direction at the current moment according to the power difference after symmetric perturbation, and update the voltage according to the voltage adjustment direction and the corrected voltage adjustment step size until the maximum power point at the current moment is determined; Obtain the maximum power point of the photovoltaic panel at each moment in real time, and monitor the power generation of the photovoltaic panel according to the difference between the actual output power and the maximum power point at each moment.

[0009] This technical solution realizes the fast adaptive tracking of the maximum power point and the refined power generation status monitoring by introducing a dynamic voltage regulation mechanism based on the fusion of electrical state drive and environmental disturbance perception. Specifically, first, by analyzing the continuous time series of voltage, current and power, and combining with the equivalent impedance model of the photovoltaic panel, dynamically estimate the degree to which the current working point deviates from the maximum power point. Then, introduce the comprehensive analysis of light intensity and temperature in terms of change amplitude, change rate and stability dimensions, construct an environmental disturbance intensity index, quantify the external inducement of the maximum power point movement trend, and act on the preliminary voltage adjustment step size, and implement a non-linear suppression and relaxation adjustment mechanism for the preliminary voltage, achieving the dual optimization goals of suppressing oscillation in a strong disturbance environment and improving the response speed in a slow-changing environment. Subsequently, by testing the response results of the power change caused by the voltage floating up and down in a symmetric perturbation manner, a feedback closed-loop adjustment logic is established, which improves the ability to quickly lock the position of the maximum power point. Finally, through the deviation analysis of the maximum power point and the actual output power at each moment, the accurate monitoring of the power generation of the photovoltaic panel is realized.

[0010] Preferably, the initial voltage adjustment step size is determined based on the following method: Obtain the voltage and power at the current moment and the previous moment, calculate the power change amount and voltage change amount at the current moment, and use the ratio of the power change amount to the voltage change amount as the distance factor; Based on the current moment's current, power, and the equivalent parallel resistance of the photovoltaic panel, calculate the total output current of the photovoltaic panel at the current moment, and use the reciprocal of the total output current as the impedance factor; Multiply the voltage at the current moment by the distance factor and the impedance factor to determine the initial voltage adjustment step size.

[0011] This technical solution constructs the initial voltage adjustment step size by introducing the distance factor and the impedance factor, reflecting the deep integration of the electrical change characteristics of the photovoltaic panel and the impedance characteristics of the photovoltaic panel in the adjustment mechanism. The adjustment strategy not only considers the current power response trend but also takes into account the equivalent load characteristics of the system, thus realizing a step size adjustment mechanism with physical constraints and adaptive characteristics.

[0012] Preferably, the environmental impact factor at the current moment is determined based on the following method: Obtain the historical light intensity and historical temperature at the current moment; Use the product of the change amplitude and change rate of the light intensity at the current moment and the stability of the historical light intensity as the light intensity impact factor at the current moment; Use the product of the change amplitude and change rate of the temperature at the current moment and the stability of the historical temperature as the temperature impact factor at the current moment; Take the sum of the light intensity impact factor and temperature impact factor at the current moment as the environmental impact factor at the current moment.

[0013] This technical solution constructs the environmental impact factor by comprehensively considering the change characteristics of two key environmental variables, light intensity and temperature, reflecting the accurate quantification of the dynamic nature of environmental disturbances. It effectively integrates the combined effects of light and temperature on the output performance of the photovoltaic panel. This factor, as the correction weight of the adjustment step size, realizes the non-linear regulation of the voltage adjustment step size by environmental changes.

[0014] Preferably, the stability of the historical light intensity and the stability of the historical temperature are determined based on the reciprocals of the standard deviations of the historical light intensity and the historical temperature, respectively.

[0015] Preferably, the change amplitude of the light intensity at the current moment is determined based on the difference between the light intensity at the current moment and the mean of the historical light intensity; The change amplitude of the temperature at the current moment is determined based on the difference between the temperature at the current moment and the mean of the historical temperature.

[0016] Preferably, the non-linear correction of the initial voltage adjustment step size by the environmental impact factor is based on the following relational expression: ; In the formula, is the voltage regulation step size corrected at time is the environmental impact factor at time is the preliminary voltage regulation step size at time is the cosine function, which is used to non-linearly map

[0017] This technical solution uses the cosine function to non-linearly map the environmental impact factor, realizes the dynamic correction of the preliminary voltage regulation step size, realizes the smooth, continuous and controllable regulation of the voltage, helps the photovoltaic system to achieve efficient and stable maximum power point tracking under complex and changeable environments, and improves the overall power generation performance and system robustness.

[0018] Preferably, judging the voltage adjustment direction at the current time according to the power difference after symmetric perturbation includes: performing forward perturbation and reverse perturbation respectively based on the voltage at the current time; obtaining the power after forward perturbation and the power after reverse perturbation; if the power after forward perturbation is greater than the power at the current time and the power after forward perturbation is greater than the power after reverse perturbation, it is determined that the voltage adjustment direction at the current time is to increase; if the power after reverse perturbation is greater than the power at the current time and the power after reverse perturbation is greater than the power after forward perturbation, it is determined that the voltage adjustment direction at the current time is to decrease.

[0019] Preferably, the method for determining the maximum power point at the current time is: after each symmetric perturbation operation, update the voltage according to the voltage adjustment direction determined by the perturbation operation and the corrected voltage regulation step size, and obtain the power corresponding to the updated voltage as the power after the symmetric perturbation operation; if the power after a certain symmetric perturbation operation is less than the power after the previous symmetric perturbation operation and the power after the previous symmetric perturbation operation is greater than the power after the symmetric perturbation operation before the previous one, determine the power after the previous symmetric perturbation operation as the maximum power point at the current time.

[0020] This technical solution determines the position of the maximum power point by continuously performing multiple symmetric perturbation operations and analyzing the change trend of the power before and after the symmetric perturbation. This method of judging based on the local power change trend can avoid incorrect tracking caused by instantaneous fluctuations or errors, and effectively improve the accuracy and stability of locking the maximum power point.

[0021] Preferably, the method for power generation monitoring based on the difference between the actual output power and the maximum power point at each moment is as follows: If during the monitoring process, there is a continuous time period in which the actual output power continuously deviates from the maximum power point and the degree of deviation exceeds the deviation threshold, it is determined that there is an abnormal power generation in the photovoltaic panel during this continuous time period; If during the monitoring process, there is no continuous time period in which the actual output power continuously deviates from the maximum power point and the degree of deviation exceeds the deviation threshold, it is determined that there is no abnormal power generation in the photovoltaic panel during this continuous time period. [[ID={1}]]

[0022] In a second aspect, the present invention also provides a power generation monitoring system for a photovoltaic panel. The power generation monitoring system includes a memory and a processor. A computer program is stored on the memory, and the processor executes the computer program to implement the steps of any one of the power generation monitoring methods.

[0023] The present invention has the following effects: Based on the variation relationship between voltage and power and the equivalent impedance characteristics of the photovoltaic panel, the present invention first estimates the preliminary voltage adjustment step size, and further non-linearly dynamically corrects the preliminary voltage adjustment step size in combination with the environmental change situation, realizing the adaptive control of the adjustment step size to the environmental disturbance intensity, and overcoming the defect that the fixed step size in the traditional conductance increment method cannot take into account both the dynamic response speed and the steady-state tracking accuracy. The precise locking of the maximum power point is achieved through the symmetric perturbation method, enabling the photovoltaic panel to stably operate in the optimal power output state under different environmental conditions and improving the accuracy of power generation monitoring. Description of the Drawings

[0024] Figure 1 is a schematic flowchart of the method of the present invention; Figure 2 is a schematic flowchart of the method of step S5 of the present invention. Detailed Embodiments

[0025] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0026] A power generation monitoring method and system for a photovoltaic panel provided by the present invention, as Figure 1 shown in, includes: S1: Real-time collect the electrical parameters and environmental parameters of the photovoltaic panel.

[0027] During the power generation monitoring process of the photovoltaic panel, the electrical parameters include voltage and current, and the voltage and current of the photovoltaic panel are synchronously sampled with a fixed sampling period of 1 second. The environmental parameters include light intensity and temperature, and the sampling frequencies of light intensity and temperature are consistent with the electrical parameters.

[0028] S2: Determine the preliminary voltage adjustment step size based on the change of the electrical parameters.

[0029] To achieve fast tracking of the maximum power point, the setting of the voltage regulation step size plays a crucial role. For each moment, when adjusting the voltage at that moment to track the maximum power point of the photovoltaic panel at that moment, if the voltage regulation step size is too large, overshoot and oscillation are likely to occur during the tracking of the maximum power point. If the step size is too small, the response is sluggish and the maximum power point cannot be tracked in a timely manner, affecting the power generation efficiency.

[0030] Therefore, this step adaptively determines the preliminary voltage regulation step size according to the electrical operating state at each moment, providing a basis for subsequent dynamic correction and tracking direction judgment.

[0031] Usually during the maximum power tracking process, it is necessary to construct a power-voltage curve. The abscissa is the voltage at each moment, and the ordinate is the power at each moment. This curve usually exhibits a single-peak characteristic, and the peak is the maximum power point, and the slope at the maximum power point is 0. On the left side of the maximum power point, as the voltage increases, the power rises and the curve slope is positive; on the right side of the maximum power point, as the voltage increases, the power drops and the curve slope is negative. Moreover, the farther away from the maximum power point, the greater the inclination of the curve, that is, the greater the absolute value of the slope; the closer to the maximum power point, the flatter the curve, and the absolute value of the slope approaches 0.

[0032] In one embodiment, the preliminary voltage regulation step size is determined based on the following method: First, take any moment as the current moment, obtain the voltage and power at the current moment and the previous moment, calculate the power change amount and voltage change amount at the current moment, and take the ratio of the power change amount and voltage change amount as the distance factor. Then, based on the current moment's current, power, and the equivalent parallel resistance of the photovoltaic panel, calculate the total output current of the photovoltaic panel at the current moment, and take the reciprocal of the total output current as the impedance factor. Finally, multiply the voltage at the current moment by the product of the distance factor and the impedance factor to determine the preliminary voltage regulation step size.

[0033] Specifically, it can be expressed by the formula:

[0034] In this formula, is the preliminary voltage regulation step size at the is the voltage at the is the voltage at the is the power at the is the power at the is the The current at a moment is the equivalent parallel resistance of the photovoltaic panel is the absolute value symbol. The calculation of the equivalent parallel resistance belongs to the conventional parameter extraction of the equivalent circuit model of the photovoltaic panel. Existing technologies usually use the open-circuit voltage decay method and the dark I-V (current-voltage) curve method to obtain the equivalent parallel resistance, and these methods have formed standard processes.

[0035] In this formula, part is calculated through a first-order difference operation the ratio of the power change amount to the voltage change amount at a moment, and this ratio represents the slope of the power-voltage curve at a moment, and it is used as a distance factor to reflect the distance between the power at the current moment and the maximum power point at the current moment. The larger it is, that is, the larger the absolute value of the slope, it means that the power at the current moment is farther from the maximum power point at the current moment (because the slope is smaller closer to the maximum power point), then the adjustment step size should be larger to approach the maximum power point faster, and vice versa.

[0036] In this formula, part is the impedance factor, which is used to dynamically adjust the sensitivity of the step size. reflects the effective output current of the photovoltaic panel at a moment reflects the current lost by the photovoltaic panel due to its own impedance part represents the total output current of the photovoltaic panel at a moment, which reflects the power generation state of the photovoltaic panel at a moment. The larger the total output current, the more likely it is that the photovoltaic panel is in a high-power state. Therefore, when tracking the maximum power point, it should be more cautious and the step size should be smaller. Therefore, by reducing the sensitivity of the voltage step size, it is prevented that at a high-power operating point close to the maximum power point, the adjustment step size is too large, resulting in power oscillation.

[0037] In short, this formula is based on and, according to the distance between the power at a moment and the maximum power point and the impedance characteristics of the photovoltaic panel itself, obtains the preliminary voltage adjustment step size. When the operating point at the current moment is far from the maximum power point, the step size is increased to improve the tracking speed, and when approaching the maximum power point, the step size is decreased to improve the positioning accuracy, which meets the voltage adjustment requirements.

[0038] S3: Determine the environmental impact factor according to the change of environmental parameters.

[0039] Since the electrical parameters of the photovoltaic panel are also affected by the environment, when the light intensity or temperature changes, parameters such as the open-circuit voltage, short-circuit current, and internal resistance of the photovoltaic panel will change, resulting in an overall shift in the power-voltage curve.

[0040] Therefore, this step further analyzes the change characteristics of the environment and evaluates the environmental impact factor at each moment to quantify the interference degree of environmental factors on the adjustment step size.

[0041] In one embodiment, the environmental impact factor is determined based on the following method: Obtain all the light intensities and temperatures within the previous 1 minute (empirical value) of the current moment as the historical light intensity and historical temperature of the current moment, and calculate the mean and standard deviation of the historical light intensity.

[0042] Determine the environmental impact factor according to the following relational expression:

[0043] In this formula, is the environmental impact factor at is the light intensity at is the light intensity at is the mean of all historical light intensities at is the normalization function. is the standard deviation of all historical light intensities at is the temperature at is the temperature at is the mean of all historical temperatures at is the standard deviation of all historical temperatures at, and the standard deviation is used to reflect the degree of data fluctuation.

[0044] In this formula, the part is the light intensity impact factor at the larger the value of this part, the greater the impact of the light intensity at is the change amplitude of the light intensity at reflects the change rate of the light intensity at reflects the stability of the historical light intensity at. If The greater the change range of the light intensity at a moment and the faster the change rate, and the better the stability of the historical light intensity, it indicates that the change of the light intensity at a moment is more obvious, and the greater the impact on the adjustment of the voltage step. Vice versa.

[0045] In this formula, the part is the temperature influence factor at a moment. The greater the value of this part, it indicates that the influence of the temperature at a moment on the voltage regulation is greater. is the change range of the temperature at a moment, reflects the change rate of the temperature at a moment, reflects the stability of the historical temperature at a moment. If the change range of the temperature at a moment is greater, the change rate is faster, and the stability of the historical temperature is better, it indicates that the change of the temperature at a moment is more intense, and it is more obvious relative to the historical temperature change, and the greater the impact on the voltage step adjustment. Vice versa.

[0046] In short, the greater, it indicates that the environment under the working conditions at a moment is more unstable, indicating that there is a sudden change in temperature or light. In the case of an unstable environment, the voltage step should be adjusted carefully to reduce the influence of environmental factors. the smaller, it indicates that the environment under the working conditions at a moment is more stable, and the environmental influence on the voltage step adjustment is smaller, and it can be adjusted stably according to the conventional step.

[0047] S4: Use the environmental influence factor to adaptively correct the preliminary voltage adjustment step.

[0048] During the power generation monitoring of the photovoltaic panel, the changes of the light intensity and temperature in the environment often have non-linear and uncertain characteristics, which are likely to cause rapid fluctuations or slow drifts in the output characteristics of the photovoltaic panel. If the adjustment strategy cannot adapt to the strength changes of environmental disturbances, it is easy to cause oscillations or lags in the maximum power point tracking process.

[0049] Therefore, in this step, the preliminary voltage adjustment step is non-linearly scaled by the environmental influence factor, so that when adjusting the voltage, the interference of environmental factors is fully considered. When the environment changes violently, the step is converged to suppress overshoot, and when the environment is stable, the step is relaxed to improve the tracking efficiency, so as to realize the adaptive dynamic control of the voltage adjustment rate and effectively improve the stability and accuracy of the maximum power point locking.

[0050] In one embodiment, the adaptive correction of the preliminary voltage regulation step size is performed based on the following formula:

[0051] In the formula, is the corrected voltage regulation step size at time is the environmental impact factor at time is the preliminary voltage regulation step size at time is the cosine function, which is used to nonlinearly map to an angular range.

[0052] In this formula, since , belongs to , is a monotonically decreasing function in . If is smaller, it indicates that the environmental change at time has less interference on voltage regulation. When is the smallest, , which means that the environment is stable and basically has no interference on voltage regulation. At this time, , , which means that the maximum power point tracking operation can be directly performed by maintaining the initial voltage regulation step size. If is larger, it indicates that the environmental change at time has greater interference on voltage regulation. When is the largest, , which means that the environment changes violently and has a large interference on voltage regulation. A larger suppression of the regulation step size is required. It is set to suppress at most half of the regulation step size to avoid excessive suppression. At this time, , , which means that the maximum power point tracking operation is performed according to half of the initial voltage regulation step size.

[0053] In summary, this regulation formula performs non-linear adaptive correction on the preliminary voltage regulation step size through the environmental impact factor. Its core significance lies in: using the monotonically decreasing characteristic of the cosine function, mapping the severity of environmental change to the suppression coefficient of step size regulation. When the environment is stable, a small correction is made to the initial voltage regulation step size to ensure the tracking efficiency; when the environment changes violently, a large correction is made to the initial voltage regulation step size, thereby suppressing the overshoot of regulation caused by environmental disturbances.

[0054] This adaptive correction mechanism can dynamically balance the tracking speed and anti-interference ability, effectively reduce power oscillation when the environment fluctuates, quickly lock the maximum power point when the environment is stable, and improve the adaptability and tracking accuracy of the photovoltaic panel power generation monitoring system to complex working conditions.

[0055] S5: Perform a symmetric perturbation operation based on the corrected voltage adjustment step size to determine the maximum power point.

[0056] Symmetric perturbation refers to the forward and reverse adjustment of the voltage of the photovoltaic panel, which is used to detect the maximum power point and belongs to an anti-interference strategy. By perturbing the voltage and observing the power change, it is verified whether the current voltage is near the maximum power point, and then adjustments are made. The purpose is to test the effectiveness of the current voltage by perturbing the voltage, so as to ensure that the system is stable near the maximum power point, reduce power oscillation and improve the tracking accuracy.

[0057] Specifically, perform multiple symmetric perturbations on the voltage at the current moment, judge the voltage adjustment direction at the current moment according to the power difference after each symmetric perturbation, and update the voltage according to the voltage adjustment direction and the corrected voltage adjustment step size (update once for each symmetric perturbation) until the maximum power point at the current moment is determined.

[0058] Such as Figure 2 shown, including: S51: Perform a symmetric perturbation once.

[0059] Perform the first symmetric perturbation on the voltage at the current moment, including: Perform forward perturbation and reverse perturbation ; The power value after forward perturbation is ; The power value after reverse perturbation is ; Among them, represents the output current of the photovoltaic panel after forward perturbation, represents the output current of the photovoltaic panel after reverse perturbation, is the voltage at moment, is the adjusted step size of the voltage after correction at

[0060] S52: Judge the voltage adjustment direction at the current moment according to the power difference after symmetric perturbation.

[0061] Set the sign function to represent the voltage adjustment direction:

[0062] If , indicating that after the first symmetrical disturbance, the power of the photovoltaic panel changes positively, and the output power of the photovoltaic panel increases, which means that the system is approaching the maximum power point. Therefore, the voltage needs to be increased appropriately, and it is determined that the voltage adjustment direction at the current moment is increasing.

[0063] if , indicating that after the first symmetrical disturbance, the power of the photovoltaic panel changes negatively, and the output power of the photovoltaic panel decreases, which means that the system is moving away from the maximum power point. Therefore, the voltage needs to be appropriately reduced. It is determined that the voltage adjustment direction at the current moment is decreasing.

[0064] In summary, the use of the sign function shows that the direction of voltage update is closely related to the direction of power change. By comparing the power at the current moment The power after the first perturbation is calculated using the sign function to determine whether the power changes in the expected direction. If the power changes in a positive direction, the voltage should increase; if the power changes in a negative direction, the voltage should decrease.

[0065] S53: After each symmetrical disturbance, the voltage is updated according to the voltage adjustment direction and the voltage correction adjustment step size.

[0066] Specifically, the voltage update strategy is set as:

[0067] In this formula, for The updated voltage corresponding to the first symmetrical perturbation is: for The voltage at the moment, is a symbolic function, for The voltage at the moment is adjusted by the corrected adjustment step.

[0068] S54: Obtain the power of the updated voltage, and use the updated voltage as the new voltage at the current moment, and repeat steps S51 to S53 until the maximum power point at the current moment is determined.

[0069] Specifically, continue to for The new voltage at time t, repeating the symmetric perturbation-update strategy of this step, is obtained , and so on, repeat continuously, and after each symmetrical disturbance, judge whether the maximum power point at the current moment can be determined once. If the maximum power point at the current moment can be determined, stop repeating and the disturbance operation ends.

[0070] The method for determining the maximum power point at the current moment is: If the power of the updated voltage corresponding to a certain symmetric perturbation is less than the power of the updated voltage corresponding to the previous symmetric perturbation, and the power of the updated voltage corresponding to the previous symmetric perturbation is greater than the power of the updated voltage corresponding to the symmetric perturbation before the previous one, then the power after the previous symmetric perturbation operation is determined as the maximum power point at the current moment.

[0071] For example, when after the th perturbation, the output power starts to decrease, that is , and after the previous perturbation, the output power is increasing, that is , then the after the previous perturbation is taken as the optimal voltage of the photovoltaic panel at the current moment. At this voltage, the photovoltaic panel is at the maximum power point, and the output power is .

[0072] In summary, through step S51 - step S54, the maximum power point at the current moment is obtained.

[0073] S6: Perform power generation monitoring based on the difference between the real-time output power and the maximum power point.

[0074] During the power generation monitoring process of the photovoltaic panel, the maximum power point at each moment is obtained in real time according to the operations of step S2 - step S5. If within any consecutive 1 minute (empirical value), the actual output power at all moments deviates from its respective maximum power point, and the deviation exceeds 20% (empirical value), it is determined that there is an abnormal power generation of the photovoltaic panel within this 1 minute. If this situation does not exist, it is determined that there is no abnormal power generation of the photovoltaic panel. Through this method, the system can ensure that the photovoltaic panel can always operate near the maximum power point under different light, temperature, and weather conditions, and can identify and handle potential abnormal situations at the same time.

[0075] A power generation monitoring system for a photovoltaic panel according to the present invention includes a memory and a processor. A computer program is stored on the memory, and the processor executes the computer program to implement the operations of step S1 - step S6, and perform power generation monitoring on the photovoltaic panel.

[0076] Although this specification has shown and described multiple embodiments of the present invention, it is obvious to those skilled in the art that such embodiments are provided by way of example only.

Claims

1. A power generation monitoring method for a photovoltaic panel, characterized in that, Including: Real-time collecting the voltage, current, temperature and light intensity of the photovoltaic panel; Taking any moment as the current moment, based on the voltage, current and power values at the current moment and the previous moment, and combining with the equivalent impedance characteristics of the photovoltaic panel, determining the preliminary voltage adjustment step size, where the preliminary voltage adjustment step size is used to adjust the rate of tracking the maximum power point; Based on the change amplitude, change rate and historical stability of the light intensity and temperature at the current moment respectively, determining the environmental impact factor at the current moment, and non-linearly correcting the preliminary voltage adjustment step size through the environmental impact factor, so as to limit the step size amplitude when the environment changes violently and increase the step size amplitude when the environment changes stably, obtaining the corrected voltage adjustment step size; Based on the corrected voltage adjustment step size, performing multiple symmetric perturbation operations on the voltage at the current moment, judging the voltage adjustment direction at the current moment according to the power difference after the symmetric perturbation, and updating the voltage according to the voltage adjustment direction and the corrected voltage adjustment step size until the maximum power point at the current moment is determined; Real-time obtaining the maximum power point of the photovoltaic panel at each moment, and performing power generation monitoring on the photovoltaic panel according to the difference between the actual output power and the maximum power point at each moment.

2. The power generation monitoring method for a photovoltaic panel according to claim 1, characterized in that The preliminary voltage adjustment step size is determined based on the following method: Obtaining the voltage and power at the current moment and the previous moment, calculating the power change amount and voltage change amount at the current moment, and taking the ratio of the power change amount and the voltage change amount as the distance factor; Based on the current of the current moment, power and the equivalent parallel resistance of the photovoltaic panel, calculating the total output current of the photovoltaic panel at the current moment, and taking the reciprocal of the total output current as the impedance factor; Determining the product of the voltage at the current moment, the distance factor and the impedance factor as the preliminary voltage adjustment step size.

3. The power generation monitoring method for a photovoltaic panel according to claim 1, characterized in that, The environmental impact factor at the current moment is determined based on the following method: Obtaining the historical light intensity and historical temperature at the current moment; Taking the product of the change amplitude and change rate of the light intensity at the current moment and the stability of the historical light intensity as the light intensity impact factor at the current moment; Taking the product of the change amplitude and change rate of the temperature at the current moment and the stability of the historical temperature as the temperature impact factor at the current moment; Taking the sum of the light intensity impact factor and temperature impact factor at the current moment as the environmental impact factor at the current moment.

4. The power generation monitoring method for a photovoltaic panel according to claim 3, wherein The stability of the historical light intensity and the stability of the historical temperature are respectively determined based on the reciprocal of the standard deviation of the historical light intensity and the reciprocal of the standard deviation of the historical temperature.

5. The power generation monitoring method for a photovoltaic panel according to claim 3, characterized in that, The change amplitude of the light intensity at the current moment is determined based on the difference between the light intensity at the current moment and the mean value of the historical light intensity; the change amplitude of the temperature at the current moment is determined based on the difference between the temperature at the current moment and the mean value of the historical temperature.

6. The power generation monitoring method for a photovoltaic panel according to claim 1, wherein The non-linear correction of the preliminary voltage adjustment step size through the environmental impact factor is carried out based on the following relational expression: ； In the formula, is the voltage regulation step size corrected at time is the environmental impact factor at time is the preliminary voltage regulation step size at time is the cosine function used to non-linearly map to an angular range.

7. The power generation monitoring method for a photovoltaic panel according to claim 1, characterized in that, Judging the voltage adjustment direction at the current moment according to the power difference after the symmetric perturbation includes: Performing forward perturbation and reverse perturbation respectively based on the voltage at the current moment; Obtaining the power after the forward perturbation and the power after the reverse perturbation; If the power after the positive perturbation is greater than the power at the current moment, and the power after the positive perturbation is greater than the power after the negative perturbation, it is determined that the voltage adjustment direction at the current moment is to increase; If the power after the negative perturbation is greater than the power at the current moment, and the power after the negative perturbation is greater than the power after the positive perturbation, it is determined that the voltage adjustment direction at the current moment is to decrease.

8. The power generation monitoring method for a photovoltaic panel according to claim 1, characterized in that, The method for determining the maximum power point at the current moment is as follows: After each symmetric perturbation operation, update the voltage according to the voltage adjustment direction determined by the perturbation operation and the corrected voltage adjustment step size, and obtain the power corresponding to the updated voltage as the power after the symmetric perturbation operation; If the power after a certain symmetric perturbation operation is less than the power after the previous symmetric perturbation operation, and the power after the previous symmetric perturbation operation is greater than the power after the symmetric perturbation operation before the previous one, determine the power after the previous symmetric perturbation operation as the maximum power point at the current moment.

9. The power generation monitoring method for a photovoltaic panel according to claim 1, characterized in that The method for power generation monitoring based on the difference between the actual output power at each moment and the maximum power point is as follows: If during the monitoring process, there is a continuous time period in which the actual output power continuously deviates from the maximum power point and the degree of deviation exceeds the deviation threshold, it is determined that there is an abnormal power generation of the photovoltaic panel during this continuous time period; If during the monitoring process, there is no continuous time period in which the actual output power continuously deviates from the maximum power point and the degree of deviation exceeds the deviation threshold, it is determined that there is no abnormal power generation of the photovoltaic panel during this continuous time period.

10. A power generation monitoring system for a photovoltaic panel, characterized in that, The power generation monitoring system includes a memory and a processor. A computer program is stored on the memory, and the processor executes the computer program to implement the steps of the power generation monitoring method according to any one of claims 1-9.

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