Control method, system and equipment suitable for photovoltaic inverter power supply

Abstract

The invention relates to the technical field of photovoltaic power supply, in particular to a control method, system and equipment suitable for a photovoltaic inverter power supply, and the method comprises the steps: determining the light receiving degree of each photovoltaic panel according to the reduction conditions of the current and voltage of each photovoltaic panel in a photovoltaic system; when the total current change speed of the photovoltaic system meets a first condition, determining the light receiving deviation of each photovoltaic panel according to the light receiving degree of each photovoltaic panel, and obtaining the light receiving fluctuation degree of the photovoltaic system; when the light receiving fluctuation degree meets a second condition, determining the overall light receiving change condition of the photovoltaic system according to the change rule of the light receiving degree of each photovoltaic panel; the initial disturbance step length is adjusted according to the overall light receiving change condition, the actual condition of photovoltaic power generation can be dynamically matched, and therefore the accuracy and reliability of disturbance step length setting are ensured. When the perturbation and observation method is adopted to carry out photovoltaic inversion control subsequently, the control reliability of the photovoltaic inversion power supply can be improved, and the photovoltaic power supply stability is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power supply, and in particular to a control method, system and device suitable for a photovoltaic inverter power supply. Background Art

[0002] As a key device in the photovoltaic system, the photovoltaic inverter converts direct current into alternating current and tracks the maximum output power of the photovoltaic module array, so that it can be connected to the power grid or used in electrical equipment with minimal conversion loss and optimal power quality.

[0003] During photovoltaic power generation, numerous factors influence the efficiency of photovoltaic panels, including their internal structure and characteristics, as well as external environmental factors such as light intensity and temperature. Regardless of environmental fluctuations, photovoltaic panels always maintain a single maximum power point. Maximum power point tracking (MPPT) technology, based on its control algorithm, tracks the maximum power point of photovoltaic cells, enabling the system to maintain high power generation efficiency under varying environmental conditions, typically increasing power generation by 5%-20%.

[0004] The most commonly used maximum power point tracking (MPPT) algorithm is usually the perturbation and observation method. The core idea of ​​the perturbation and observation method is to actively perturb the operating point (usually the voltage) of the photovoltaic panel, observe the direction of change in the output power, determine whether the perturbation direction is correct, and adjust the operating point closer to the maximum power point accordingly. Therefore, the perturbation and observation method gradually approaches the maximum power point by adjusting the voltage in small amplitudes and using the adjusted power feedback. The perturbation step size in the perturbation and observation method is a key parameter of the perturbation and observation method. However, the existing perturbation step size is fixed and cannot match the actual conditions of photovoltaic power generation. This leads to inaccurate perturbation step size settings, affecting the stability of photovoltaic power supply. Summary of the Invention

[0005] In order to solve the technical problem of inaccurate perturbation step size setting in the perturbation observation method when using the perturbation observation method for photovoltaic inverter control, the purpose of the present invention is to provide a control method, system and device suitable for photovoltaic inverter power supply. The technical solution adopted is as follows: In a first aspect of the present invention, a control method applicable to a photovoltaic inverter power supply is provided, comprising: Determine the light exposure level of each photovoltaic panel based on the reduction of current and voltage of each photovoltaic panel in the photovoltaic system; When the total current change rate of the photovoltaic system meets the first condition, the light reception deviation of each photovoltaic panel is determined according to the light reception degree of each photovoltaic panel, and the light reception fluctuation degree of the photovoltaic system is obtained; When the light fluctuation degree meets the second condition, the overall light variation of the photovoltaic system is determined according to the variation law of the light variation degree of each photovoltaic panel; The initial disturbance step size is adjusted according to the overall light change.

[0006] In an exemplary embodiment, the process of obtaining the light exposure level includes: Obtaining a current current of the photovoltaic panel, and determining a first shading performance characteristic characterized by a current reduction based on a difference between the current current and a preset standard current; Obtaining a current voltage of the photovoltaic panel, and determining a second shading performance characteristic represented by a voltage drop based on a difference between the current voltage and a preset standard voltage; The first light-shielding performance characteristic and the second light-shielding performance characteristic are integrated to obtain the light-receiving degree of the photovoltaic panel; the light-receiving degree is inversely correlated with both the first light-shielding performance characteristic and the second light-shielding performance characteristic.

[0007] In an exemplary embodiment, the process of obtaining the light deviation includes: The difference between the light receiving level of each photovoltaic panel and the average light receiving level is used as the light receiving deviation of each photovoltaic panel; the average light receiving level is the average value of the light receiving levels of all photovoltaic panels.

[0008] In an exemplary embodiment, the process of acquiring the light fluctuation degree includes: Determine the maximum light receiving deviation from the light receiving deviations of each photovoltaic panel; The light reception fluctuation degree is obtained from the light reception degree mean value and the maximum light reception deviation; the light reception fluctuation degree is positively correlated with the maximum light reception deviation and inversely correlated with the light reception degree mean value.

[0009] In an exemplary embodiment, the process of acquiring the overall light exposure change includes: Construct a photovoltaic panel location matrix based on the geographical location of each photovoltaic panel; Determining the speed of change of the light exposure level of each row of photovoltaic panels in the photovoltaic panel position matrix, and fusing the speed of change to obtain a lateral light exposure level change feature; Determining the speed of change of the light exposure level of each column of photovoltaic panels in the photovoltaic panel position matrix, and fusing them to obtain a longitudinal light exposure level change feature; The overall light exposure change condition is obtained by fusing the horizontal light exposure change characteristic and the vertical light exposure change characteristic.

[0010] In an exemplary embodiment, the process of acquiring the speed of change of the light exposure level of each row of photovoltaic panels includes: Calculate the average value of the light exposure of each photovoltaic panel in the candidate row of photovoltaic panels to obtain the light exposure of the candidate row of photovoltaic panels; Calculating a rate of change in the light exposure level of the candidate row of photovoltaic panels; The process of acquiring the lateral light exposure degree variation characteristic includes: calculating an average value of the speed of change of the light exposure degree of each row of photovoltaic panels as the lateral light exposure degree variation characteristic.

[0011] In an exemplary embodiment, adjusting the initial disturbance step size according to the overall light exposure change includes: An adjustment coefficient is obtained according to the overall light exposure change; the adjustment coefficient is positively correlated with the overall light exposure change; The initial disturbance step size is adjusted according to the adjustment coefficient.

[0012] In an exemplary embodiment, the control method applicable to a photovoltaic inverter power supply further includes: When the light fluctuation degree does not satisfy the second condition, an adjustment coefficient is obtained according to the total current change speed; the adjustment coefficient is positively correlated with the total current change speed; The initial disturbance step size is adjusted according to the adjustment coefficient.

[0013] In a second aspect of the present invention, a control system suitable for a photovoltaic inverter power supply is provided, comprising: a memory and a processor; the memory is connected to the processor; the memory is used to store program instructions; and the processor is used to implement the above-mentioned control method suitable for a photovoltaic inverter power supply when the program instructions are executed.

[0014] In a third aspect of the present invention, a control device suitable for a photovoltaic inverter power supply is provided, comprising a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-mentioned control method suitable for a photovoltaic inverter power supply.

[0015] The present invention has the following beneficial effects: the present invention determines the overall light exposure change of the photovoltaic system based on the change in current and voltage of each photovoltaic panel in the photovoltaic system, and thus adjusts the initial disturbance step size according to the overall light exposure change, so that the adjusted disturbance step size is related to the overall state of the photovoltaic system. When the overall state of the photovoltaic system changes, the disturbance step size will also change accordingly, realizing adaptive adjustment of the disturbance step size. Compared with the fixed setting of the disturbance step size, it can dynamically match the actual situation of photovoltaic power generation, thereby ensuring the accuracy and reliability of the disturbance step size setting. Subsequently, when the disturbance observation method is used for photovoltaic inverter control, the control reliability of the photovoltaic inverter power supply can be improved, and the stability of the photovoltaic power supply can be ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1This is a flowchart of a control method for a photovoltaic inverter power supply provided by an embodiment of the present invention; Figure 2 is a flow chart for obtaining the light exposure level provided by one embodiment of the present invention; Figure 3 This is a flow chart for obtaining the light fluctuation degree provided by one embodiment of the present invention; Figure 4 This is a flow chart for obtaining the overall light exposure change provided by one embodiment of the present invention; Figure 5 This is a flow chart for obtaining the speed of change of the light exposure level of each row of photovoltaic panels provided by one embodiment of the present invention; Figure 6 This is a flow chart of adjusting the initial disturbance step size based on the overall light exposure change provided by one embodiment of the present invention; Figure 7 A control method for a photovoltaic inverter power supply provided by an embodiment of the present invention further includes a flowchart of the steps. DETAILED DESCRIPTION

[0017] To further illustrate the technical means and effects employed by the present invention to achieve its intended objectives, the following detailed description of the specific embodiments, structures, features, and effects of the present invention is provided in conjunction with the accompanying drawings and preferred embodiments. In the following description, references to "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this invention pertains. The data and information collected in this application were obtained with full consent and authorization.

[0019] In a photovoltaic system, photovoltaic panels serve as the core power generation component. The electricity they generate must undergo a series of processing steps before it can be successfully integrated into the power grid and effectively utilized. To achieve better energy output and lower wiring costs, photovoltaic panels are typically configured in a mixed series-parallel configuration. This involves connecting multiple groups of photovoltaic panels in series and then in parallel to form a photovoltaic system. In this embodiment, the photovoltaic panels in the photovoltaic system are of the same model to ensure perfect electrical parameter matching.

[0020] When sunlight strikes the surface of photovoltaic panels, it converts light energy into direct current (DC) electricity. This DC power is first aggregated by a combiner box and then centrally processed and protected by a DC distribution cabinet. The power then passes through a photovoltaic inverter, which performs the core task of converting DC to AC. This converted AC power is smoothed by filters to remove high-frequency harmonics and ensure power quality. The transformer regulates the voltage to match grid requirements and ensure stable grid connection. Throughout this process, the photovoltaic inverter plays multiple key roles, including current control, grid synchronization, MPPT, and anti-islanding protection.

[0021] Traditional MPPT uses a fixed perturbation step size for maximum power point tracking, which is difficult to adapt to rapid changes in light. However, when the light conditions on the photovoltaic panel surface change, its current and voltage data will also change. Therefore, the current and voltage data of the photovoltaic panel can reflect its light conditions, thereby performing maximum power point tracking with an adaptive perturbation step size.

[0022] The current and voltage of each photovoltaic panel are collected. A voltage sensor, specifically an isolated differential voltage sensor, is installed in parallel inside the junction box of each photovoltaic panel. The measurement point is directly connected to the positive and negative output terminals of the photovoltaic panel to collect the voltage data of the photovoltaic panel. A current sensor, such as a Hall current sensor, is installed on the output line of each photovoltaic panel to collect the current of each photovoltaic panel. At the same time, a current sensor is also provided on the total output line of the photovoltaic system to collect the total current of the photovoltaic system. The sampling frequency of each sensor is set according to actual needs. In this embodiment, 1kHz is used as an example.

[0023] This embodiment provides a control method applicable to a photovoltaic inverter power supply, which is used to adjust the perturbation step size in the MPPT, thereby controlling the photovoltaic inverter power supply using the MPPT based on the adjusted perturbation step size. It should be understood that when executing the control method applicable to a photovoltaic inverter power supply provided by this embodiment, it is necessary to ensure that the photovoltaic system is in normal operation. Therefore, if a fault occurs in the photovoltaic system, such as a short circuit or open circuit, the fault diagnosis system equipped in the photovoltaic system will be used to perform the fault diagnosis, and the control method applicable to the photovoltaic inverter power supply provided by this embodiment will no longer be executed. Therefore, the control method applicable to a photovoltaic inverter power supply provided by this embodiment is only executed when the photovoltaic system is in normal operation, thereby ensuring the accuracy of the obtained results.

[0024] like Figure 1 As shown, the control method for a photovoltaic inverter power supply provided in this embodiment includes the following steps: Step 1: Determine the light exposure level of each photovoltaic panel based on the reduction in current and voltage of each photovoltaic panel in the photovoltaic system; Step 2: When the total current change rate of the photovoltaic system meets the first condition, the light reception deviation of each photovoltaic panel is determined based on the light reception degree of each photovoltaic panel to obtain the light reception fluctuation degree of the photovoltaic system; Step 3: When the light fluctuation degree meets the second condition, the overall light variation of the photovoltaic system is determined according to the variation law of the light variation of each photovoltaic panel; Step 4: Adjust the initial perturbation step size based on the overall light changes.

[0025] Each step is described in detail below with reference to the accompanying drawings.

[0026] Step 1: Determine the light exposure level of each photovoltaic panel based on the reduction in current and voltage of each photovoltaic panel in the photovoltaic system.

[0027] Since a photovoltaic system is composed of photovoltaic panels connected in series and parallel, for ease of description, any one photovoltaic panel is taken as an example and any one photovoltaic panel is defined as a candidate photovoltaic panel.

[0028] Since the voltage and current of a candidate photovoltaic panel are controlled by light intensity, the higher the light intensity, the greater the voltage and current. Therefore, the light exposure level of the candidate photovoltaic panel is determined based on the reduction in current and voltage of the candidate photovoltaic panel. The light exposure level refers to the degree of light exposure, which can also be understood as light intensity.

[0029] This embodiment predetermines a time period. Based on the data information of the photovoltaic system during each time period, an adjusted perturbation step size corresponding to the time period is determined. Then, based on the determined perturbation step size, MPPT is used to control the photovoltaic inverter power supply during the next one or more time periods. It should be understood that the length of the time period is set based on actual conditions. It should be understood that if the time period consists of multiple time points, the voltage of the candidate photovoltaic panel is the average of the voltages at each moment in the time period, and the current of the candidate photovoltaic panel is the average of the currents at each moment in the time period.

[0030] In an exemplary embodiment, Figure 2 As shown, a specific process of obtaining the light exposure degree is given as follows: Step 11: Obtain the current of the photovoltaic panel, and determine the first shading performance feature represented by the current reduction based on the difference between the current current and the preset standard current.

[0031] Obtain the current current of the candidate photovoltaic panel, i.e., the current of the candidate photovoltaic panel during the current time period (i.e., the average current at each moment in the current time period, and the same applies to the voltage below). It should be understood that if the time period is a time period, the current moment is the last moment in the current time period.

[0032] In an exemplary embodiment, the preset standard current can be the current output by the photovoltaic panel when exposed to the strongest light intensity in the area and without any obstructions. Therefore, the preset standard current can be understood as the maximum current that the photovoltaic panel can output in the area, or can be directly understood as the maximum current that the photovoltaic panel can output. In this case, the preset standard current is the same for all photovoltaic panels in the photovoltaic system.

[0033] Determine the difference between the current current of the candidate photovoltaic panel and the preset standard current, and determine the first shading performance feature characterized by the current reduction of the candidate photovoltaic panel based on the difference. The first shading performance feature indicates the degree to which the light of the candidate photovoltaic panel is blocked. Among them, the gap can be characterized by a ratio, that is, the ratio of the current current of the candidate photovoltaic panel to the preset standard current is calculated. It should be understood that the ratio is greater than or equal to 0 and less than or equal to 1. The larger the ratio, the smaller the difference between the current current of the candidate photovoltaic panel and the preset standard current, the smaller the current reduction amplitude, and the weaker the first shading performance feature. Then, the first shading performance feature is inversely correlated with the ratio. In an exemplary embodiment, a specific quantification method of the first shading performance feature is given as follows: ; in, represents the first shading performance characteristic of the i-th photovoltaic panel; Indicates the preset standard current; Represents the current of the i-th photovoltaic panel.

[0034] Step 12: Obtain the current voltage of the photovoltaic panel, and determine the second shading performance characteristic represented by the voltage reduction based on the difference between the current voltage and the preset standard voltage.

[0035] Obtain the current voltage of the candidate photovoltaic panel, i.e., the voltage of the candidate photovoltaic panel during the current time period. In an exemplary embodiment, the preset standard voltage may be the voltage of the photovoltaic panel when exposed to the strongest light intensity in the area and without any obstructions. Therefore, the preset standard voltage can be understood as the maximum voltage that the photovoltaic panel can output in the area, or can be directly understood as the maximum voltage that the photovoltaic panel can output. In this case, the preset standard voltage is the same for all photovoltaic panels in the photovoltaic system.

[0036] Determine the gap between the current voltage of the candidate photovoltaic panel and the preset standard voltage, and determine the second shading performance characteristic represented by the voltage reduction of the candidate photovoltaic panel based on the gap. The second shading performance characteristic indicates the degree to which the light of the candidate photovoltaic panel is blocked. Among them, the gap can be characterized by a ratio, that is, the ratio of the current voltage of the candidate photovoltaic panel to the preset standard voltage is calculated. It should be understood that the ratio is greater than or equal to 0 and less than or equal to 1. The larger the ratio is, the smaller the gap between the current voltage of the candidate photovoltaic panel and the preset standard voltage is, the smaller the voltage reduction is, and the weaker the second shading performance characteristic is. Then, the second shading performance characteristic is inversely correlated with the ratio. In an exemplary embodiment, a specific quantification method of the second shading performance characteristic is given as follows: ; in, represents the second shading performance characteristics of the i-th photovoltaic panel; Indicates the preset standard voltage; Represents the current voltage of the i-th photovoltaic panel.

[0037] Step 13: The first shading performance characteristic and the second shading performance characteristic are integrated to obtain the light receiving degree of the photovoltaic panel.

[0038] The stronger the first light-shielding performance characteristic of the candidate photovoltaic panel, the stronger the degree to which the current of the candidate photovoltaic panel is blocked by light, and the lower the degree of light received by the candidate photovoltaic panel. Therefore, the degree of light received is inversely correlated with the first light-shielding performance characteristic; the stronger the second light-shielding performance characteristic of the candidate photovoltaic panel, the stronger the degree to which the voltage of the candidate photovoltaic panel is blocked by light, and the lower the degree of light received by the candidate photovoltaic panel. Therefore, the degree of light received is inversely correlated with the second light-shielding performance characteristic. Based on the above logic, a specific quantification method for the degree of light received is given as follows: ; in, The light exposure level of the i-th photovoltaic panel is represented by . Using the above process, the current light exposure level of each photovoltaic panel is obtained. The light exposure level represents the degree to which the photovoltaic panel is exposed to light.

[0039] Step 2: When the total current change rate of the photovoltaic system meets the first condition, the light reception deviation of each photovoltaic panel is determined according to the light reception degree of each photovoltaic panel to obtain the light reception fluctuation degree of the photovoltaic system.

[0040] The main reason for the change in the light exposure of photovoltaic panels is obstruction by clouds, buildings, etc., so when the light exposure changes, it can be mainly divided into two situations. The first is the sudden change of the overall light intensity of the photovoltaic system, that is, the sudden change of the overall light intensity of the photovoltaic system. At this time, there is no spatial gradient in the change of light intensity, and all photovoltaic panels in the photovoltaic system change synchronously; the second is the gradual obstruction of shadows. At this time, the change in the light exposure of each photovoltaic panel is spatially distributed, and the change in light exposure propagates along the space.

[0041] To obtain the total current change rate of the photovoltaic system, in one exemplary embodiment, the average total current of the photovoltaic system at each moment in the current time period is calculated as the total current of the photovoltaic system for the current time period. Similarly, the total current of the photovoltaic system for each previous time period can be obtained to obtain the total current of the time period before the current time period. The absolute value of the difference between the total current of the current time period and the total current of the previous time period is calculated, and the obtained absolute value of the total current difference is divided by the duration of the current time period to obtain the total current change rate of the photovoltaic system for the current time period. It should be understood that if the duration of the time period is used as the unit time, the total current change rate of the photovoltaic system for the current time period is essentially the absolute value of the difference between the total current of the current time period and the total current of the previous time period. Alternatively, if the time period is a single point in time, the instantaneous rate of change of the total current for the current time period is obtained (for example, a total current change curve is obtained, and the absolute value of the tangent slope of each data point on the curve is used as the instantaneous rate of change) as the total current change rate for the current time period.

[0042] This embodiment presets a first condition for performing the subsequent processing of this step when the total current change rate of the photovoltaic system meets the first condition. In an exemplary embodiment, a current change rate threshold is preset, and the preset current change rate threshold is used to compare with the total current change rate of the photovoltaic system in the current time period to determine whether the total current change rate of the photovoltaic system in the current time period is large. The specific value of the preset current change rate threshold is set according to actual needs, such as 30mA / unit time. Then, the first condition is: the total current change rate of the photovoltaic system is greater than or equal to the preset current change rate threshold. Therefore, when the total current change rate of the photovoltaic system in the current time period is greater than or equal to the preset current change rate threshold, it indicates that the overall light intensity of the photovoltaic system has changed significantly.

[0043] The current light exposure type of the photovoltaic system is determined by the overall light exposure of the photovoltaic system. When there is a large difference in the light exposure levels of different photovoltaic panels, it is considered to be an occlusion-type light mutation; otherwise, it is an overall light mutation of the photovoltaic system.

[0044] When the total current change rate of the photovoltaic system in the current time period is greater than or equal to the preset current change rate threshold, the light exposure deviation of each photovoltaic panel is determined by the light exposure level of each photovoltaic panel. In an exemplary embodiment, the average value of the current light exposure levels of all photovoltaic panels in the photovoltaic system is calculated and defined as the mean light exposure level.

[0045] For each candidate photovoltaic panel, the difference between the current light exposure level of the candidate photovoltaic panel and the average light exposure level is obtained. Specifically, the absolute value of the difference between the current light exposure level of the candidate photovoltaic panel and the average light exposure level is calculated, and this absolute value of the difference is used as the current light exposure deviation of the candidate photovoltaic panel. In this way, the current light exposure deviation of each photovoltaic panel is obtained.

[0046] Then, the light receiving fluctuation degree of the photovoltaic system is obtained according to the light receiving deviation of each photovoltaic panel. Figure 3 As shown, a specific process for obtaining the degree of light fluctuation is given as follows: Step 21: Determine the maximum light receiving deviation from the light receiving deviations of each photovoltaic panel; Step 22: Obtain the light reception fluctuation degree from the light reception mean value and the maximum light reception deviation.

[0047] Among them, the maximum value is found from the current light reception deviation of each photovoltaic panel, which is defined as the current maximum light reception deviation. The larger the maximum light reception deviation, the stronger the fluctuation of the light reception level of the photovoltaic system, and the higher the light reception fluctuation level of the photovoltaic system, and the two are positively correlated. The higher the mean light reception level, the higher the level of light reception level of the photovoltaic system as a whole, then the lower the credibility of the maximum light reception deviation. Therefore, the mean light reception level is used to reversely characterize the credibility of the maximum light reception deviation, and the light reception fluctuation level is inversely correlated with the mean light reception level. Based on the above logic, a specific quantification method for the light reception fluctuation level is given as follows: ; in, Indicates the degree of light fluctuation of the photovoltaic system. Indicates the maximum light receiving deviation, Indicates the average light intensity.

[0048] As another implementation, the average value of the current light reception deviations of all photovoltaic panels in the photovoltaic system may be used as the current light reception fluctuation degree of the photovoltaic system.

[0049] The greater the degree of light fluctuation, the more the light of each photovoltaic panel is gradually blocked, that is, the shadow on the photovoltaic panel is gradually formed. At this time, the light conditions of each photovoltaic panel are spatially distributed.

[0050] Step 3: When the light fluctuation level meets the second condition, the overall light variation of the photovoltaic system is determined according to the variation pattern of the light variation of each photovoltaic panel.

[0051] The greater the light receiving fluctuation degree, the more gradually the light of each photovoltaic panel is blocked, i.e., the shadow on the photovoltaic panel is gradually formed, and the light receiving condition of each photovoltaic panel has a spatial distribution. When the shadow gradually blocks the surface of the photovoltaic panel to cause the change of the light receiving degree, the blocking object usually moves along a certain angle, and then the overall light receiving change of the photovoltaic system needs to be determined according to the change rule of the light receiving degree in the photovoltaic system.

[0052] The second condition is preset in the embodiment, and when the light receiving fluctuation degree meets the second condition, it indicates that the light of each photovoltaic panel is gradually blocked, and then the subsequent processing of the step is performed. In an exemplary embodiment, a light receiving fluctuation degree threshold is preset, which is used to compare with the light receiving fluctuation degree of the photovoltaic system to determine whether the light receiving fluctuation degree of the photovoltaic system in the current time period is large. The specific value of the preset light receiving fluctuation degree threshold is set by actual needs, which can be set to 0.1. Then, the second condition is that the light receiving fluctuation degree of the photovoltaic system is greater than or equal to the preset light receiving fluctuation degree threshold.

[0053] When the light receiving fluctuation degree meets the second condition, the overall light receiving change of the photovoltaic system is determined according to the change rule of the light receiving degree of each photovoltaic panel. As shown in Figure 4 A specific acquisition process of the overall light receiving change is given as follows: Step 31: A photovoltaic panel position matrix is constructed according to the geographical positions of the photovoltaic panels.

[0054] In the embodiment, the photovoltaic panels are arranged in multiple rows and multiple columns to form a photovoltaic array. Then, the geographical positions of the photovoltaic panels are determined, and a two-dimensional coordinate system is constructed with the ground plane, wherein the position of the lower left photovoltaic panel is taken as the origin of the two-dimensional coordinate system, the horizontal arrangement direction of the photovoltaic panels is taken as the X axis, and the vertical arrangement direction of the photovoltaic panels is taken as the Y axis. The geographical positions of the photovoltaic panels are mapped into the two-dimensional coordinate system to obtain the two-dimensional coordinate points of the photovoltaic panels. The photovoltaic panel position matrix is constructed according to the two-dimensional coordinate points of the photovoltaic panels. Thus, the composition of each row of photovoltaic panels and the composition of each column of photovoltaic panels in the photovoltaic panel position matrix are obtained. For any row of photovoltaic panels, the X axis coordinate points of the photovoltaic panels included are different, and the Y axis coordinate points are the same; for any column of photovoltaic panels, the X axis coordinate points of the photovoltaic panels included are the same, and the Y axis coordinate points are different.

[0055] Step 32: The change speed of the light receiving degree of each row of photovoltaic panels in the photovoltaic panel position matrix is determined, and a horizontal light receiving degree change feature is fused.

[0056] The change speed of the light receiving degree of each row of photovoltaic panels in the photovoltaic panel position matrix is determined, and a horizontal light receiving degree change feature is fused. Figure 5As shown, a specific process for obtaining the speed of change of the light exposure level of each row of photovoltaic panels is given as follows: Step 321: Calculate the average value of the light exposure levels of each photovoltaic panel in the candidate row of photovoltaic panels to obtain the light exposure level of the candidate row of photovoltaic panels.

[0057] For ease of explanation, let the candidate row of photovoltaic panels be any row of photovoltaic panels. The current light exposure level of each photovoltaic panel in the candidate row is obtained, and then the average of the current light exposure levels of each photovoltaic panel in the candidate row is calculated as the light exposure level of the candidate row photovoltaic panel in the current time period.

[0058] Step 322: Calculate the rate of change of the light exposure level of the candidate rows of photovoltaic panels.

[0059] Obtain the speed of change of the light exposure level of the candidate row photovoltaic panel. In an exemplary embodiment, obtain the light exposure level of the candidate row photovoltaic panel in the time period before the current time period, calculate the absolute value of the difference between the light exposure level of the candidate row photovoltaic panel in the current time period and the light exposure level of the previous time period, and divide the obtained absolute value of the difference by the duration of the current time period to obtain the speed of change of the light exposure level of the candidate row photovoltaic panel in the current time period. For the convenience of data processing, the absolute value of the difference between the light exposure level of the candidate row photovoltaic panel in the current time period and the light exposure level of the previous time period is used as the speed of change of the light exposure level of the candidate row photovoltaic panel in the current time period, that is, the time period is a unit time. Similarly, the speed of change of the light exposure level of each row photovoltaic panel is obtained.

[0060] Then, the light exposure change speeds of each row of photovoltaic panels in the photovoltaic panel position matrix are integrated to obtain a lateral light exposure change feature. Specifically, the average value of the light exposure change speeds of each row of photovoltaic panels is calculated as the lateral light exposure change feature.

[0061] Step 33: Determine the speed of change of the light exposure level of each column of photovoltaic panels in the photovoltaic panel position matrix, and fuse them to obtain the longitudinal light exposure level change characteristics.

[0062] The process of obtaining the speed of change of the light exposure level of each row of photovoltaic panels in the above-mentioned photovoltaic panel position matrix is ​​similar to that of obtaining the light exposure level of each row of photovoltaic panels in the above-mentioned photovoltaic panel position matrix. For the sake of convenience, the candidate column photovoltaic panel is set to be any column of photovoltaic panels. The current light exposure level of each photovoltaic panel in the candidate column photovoltaic panel is obtained, and then the average value of the current light exposure level of each photovoltaic panel in the candidate column photovoltaic panel is calculated as the light exposure level of the candidate column photovoltaic panel in the current time period. The light exposure level of the candidate column photovoltaic panel in the previous time period is obtained, and the absolute value of the difference between the light exposure level of the candidate column photovoltaic panel in the current time period and the light exposure level of the previous time period is calculated, and then divided by the duration of the current time period. The result obtained is the speed of change of the light exposure level of the candidate column photovoltaic panel in the current time period. For the convenience of data processing, the absolute value of the difference between the light exposure level of the candidate column photovoltaic panel in the current time period and the light exposure level of the previous time period is used as the speed of change of the light exposure level of the candidate column photovoltaic panel in the current time period, that is, the time period is the unit time. Similarly, the speed of change of the light exposure level of each column photovoltaic panel is obtained.

[0063] Then, the speed of change of the light exposure level of each photovoltaic panel column in the photovoltaic panel position matrix is ​​integrated to obtain the longitudinal light exposure level change feature. Specifically, the average value of the speed of change of the light exposure level of each photovoltaic panel column is calculated as the longitudinal light exposure level change feature.

[0064] Step 34: The horizontal light exposure variation characteristics and the vertical light exposure variation characteristics are integrated to obtain the overall light exposure variation.

[0065] The average values ​​of the horizontal and vertical light exposure variation characteristics are calculated, and the result obtained is the overall light exposure variation of the photovoltaic system in the current time period.

[0066] Step 4: Adjust the initial perturbation step size based on the overall light changes.

[0067] Combined with the overall light changes of the photovoltaic system in the current time period, the adaptive perturbation step size is adjusted to track the maximum power point. In an exemplary embodiment, Figure 6 As shown, the specific process of adjusting the initial perturbation step size according to the overall light change is given as follows: Step 41: Obtain an adjustment coefficient based on the overall light variation.

[0068] The adjustment coefficient for the current time period is obtained based on the overall light exposure change of the photovoltaic system in the current time period. The adjustment coefficient is positively correlated with the overall light exposure change. In an exemplary embodiment, the overall light exposure change is directly used as the adjustment coefficient.

[0069] Step 42: Adjust the initial perturbation step size according to the adjustment coefficient.

[0070] This embodiment sets an initial perturbation step size, which can be a preset maximum perturbation step size. The adjustment coefficient is multiplied by the initial perturbation step size, and the resulting product is the adjusted perturbation step size for the current time period of the photovoltaic system. Using the resulting adaptive perturbation step size, the perturbation-and-observe method is used for MPPT tracking for subsequent time periods, achieving more effective tracking results.

[0071] In an exemplary embodiment, Figure 7 As shown, the control method for a photovoltaic inverter power supply provided in this embodiment further includes the following steps: Step 5: When the light fluctuation level does not meet the second condition, the adjustment coefficient is obtained from the total current change rate.

[0072] If the degree of light fluctuation does not meet the second condition, that is, if the total current change rate of the photovoltaic system in the current time period is less than the preset current change rate threshold, it indicates that the total current change rate of the photovoltaic system in the current time period is not large. An adjustment coefficient for the current time period is then derived based on the total current change rate of the photovoltaic system in the current time period. The adjustment coefficient is positively correlated with the total current change rate. In one exemplary embodiment, the total current change rate is normalized, for example, using a tanh function, and the normalized result is the adjustment coefficient.

[0073] Step 6: Adjust the initial perturbation step size according to the adjustment coefficient.

[0074] Multiplying the adjustment coefficient by the initial perturbation step size yields the adjusted perturbation step size for the current time period of the PV system. Using the resulting adaptive perturbation step size, the perturbation-and-observe method is then used for MPPT tracking over subsequent time periods, achieving more effective tracking results.

[0075] This embodiment provides a control method for photovoltaic inverter power supplies based on the perturbation-observation method, but addresses its vulnerability to misjudgment and oscillation near the maximum power point (MPP) when light intensity changes rapidly. By collecting electrical data (voltage and current) from the photovoltaic panels and determining their light intensity, the perturbation-observation method's control step size is adaptively adjusted, improving the adaptability and efficiency of the MPPT control strategy. Based on the light intensity and predicted light intensity changes, the adaptive step size at the MPPT tracking point is calculated to achieve more efficient maximum power point tracking.

[0076] The control method for a photovoltaic inverter power supply provided in this embodiment has the following specific technical effects: it can improve power generation efficiency: through the MPPT control strategy with adaptive step size, it can more effectively track the maximum power point of the photovoltaic cell and increase the power generation of the system, which can generally increase the power generation of the system by 5%-20%; enhance adaptability: it can accurately judge the light conditions of the photovoltaic panel and adaptively adjust the disturbance step size of the MPPT according to the light conditions, thereby improving the adaptability of the system under different environmental conditions and avoiding falling into local optimality; reduce losses: reduce oscillations near the maximum power point and reduce energy loss; extend equipment life: by optimizing the MPPT control strategy, unnecessary adjustments and oscillations of the system are reduced, which helps to extend the service life of the photovoltaic inverter and related equipment; improve power quality: optimized MPPT control helps to improve power quality and ensure the stability of grid-connected power; intelligent judgment and response: it can intelligently judge the light conditions and light change types of the photovoltaic panel, provide a more accurate control basis for the system, and improve the intelligence level of the system; reduce maintenance costs: more accurate light condition judgment and prediction help to timely discover potential problems and reduce maintenance costs.

[0077] In an exemplary embodiment, this embodiment also provides a control system suitable for a photovoltaic inverter power supply, including: a memory and a processor; the memory is connected to the processor, and the memory is used to store program instructions; the processor is used to implement the steps in the above-mentioned control method embodiment suitable for a photovoltaic inverter power supply when the program instructions are executed.

[0078] In an exemplary embodiment, this embodiment also provides a control device suitable for a photovoltaic inverter power supply, including: a computer-readable storage medium, the computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, implementing the steps in the above-mentioned control method embodiment suitable for a photovoltaic inverter power supply.

[0079] It should be noted that the order in which the embodiments of the present invention are described above is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0080] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A control method for photovoltaic inverter power supply, characterized in that: include: Determine the light exposure level of each photovoltaic panel based on the reduction of current and voltage of each photovoltaic panel in the photovoltaic system; When the total current change rate of the photovoltaic system meets the first condition, the light reception deviation of each photovoltaic panel is determined according to the light reception degree of each photovoltaic panel, and the light reception fluctuation degree of the photovoltaic system is obtained; When the light fluctuation degree meets the second condition, the overall light variation of the photovoltaic system is determined according to the variation law of the light variation degree of each photovoltaic panel; The initial disturbance step size is adjusted according to the overall light change.

2. The control method for photovoltaic inverter power supply according to claim 1, characterized in that: The process of obtaining the light exposure degree includes: Obtaining a current current of the photovoltaic panel, and determining a first shading performance characteristic characterized by a current reduction based on a difference between the current current and a preset standard current; Obtaining a current voltage of the photovoltaic panel, and determining a second shading performance characteristic represented by a voltage drop based on a difference between the current voltage and a preset standard voltage; The first light-shielding performance characteristic and the second light-shielding performance characteristic are integrated to obtain the light-receiving degree of the photovoltaic panel; the light-receiving degree is inversely correlated with both the first light-shielding performance characteristic and the second light-shielding performance characteristic.

3. The control method for photovoltaic inverter power supply according to claim 1, wherein: The process of obtaining the light deviation includes: The difference between the light receiving level of each photovoltaic panel and the average light receiving level is used as the light receiving deviation of each photovoltaic panel; the average light receiving level is the average value of the light receiving levels of all photovoltaic panels.

4. The control method for photovoltaic inverter power supply according to claim 3, characterized in that: The process of obtaining the light fluctuation degree includes: Determine the maximum light receiving deviation from the light receiving deviations of each photovoltaic panel; The light reception fluctuation degree is obtained from the light reception degree mean value and the maximum light reception deviation; the light reception fluctuation degree is positively correlated with the maximum light reception deviation and inversely correlated with the light reception degree mean value.

5. The control method for photovoltaic inverter power supply according to claim 1, wherein: The process of obtaining the overall light change condition includes: Construct a photovoltaic panel location matrix based on the geographical location of each photovoltaic panel; Determining the speed of change of the light exposure level of each row of photovoltaic panels in the photovoltaic panel position matrix, and fusing the speed of change to obtain a lateral light exposure level change feature; Determining the speed of change of the light exposure level of each column of photovoltaic panels in the photovoltaic panel position matrix, and fusing them to obtain a longitudinal light exposure level change feature; The overall light exposure change condition is obtained by fusing the horizontal light exposure change characteristic and the vertical light exposure change characteristic.

6. The control method for photovoltaic inverter power supply according to claim 5, characterized in that: The process of obtaining the speed of change of the light exposure degree of each row of photovoltaic panels includes: Calculate the average value of the light exposure of each photovoltaic panel in the candidate row of photovoltaic panels to obtain the light exposure of the candidate row of photovoltaic panels; Calculating a rate of change in the light exposure level of the candidate row of photovoltaic panels; The process of acquiring the lateral light exposure degree variation characteristic includes: calculating an average value of the speed of change of the light exposure degree of each row of photovoltaic panels as the lateral light exposure degree variation characteristic.

7. The control method for photovoltaic inverter power supply according to claim 1, wherein: The adjusting of the initial disturbance step size according to the overall light receiving change comprises: An adjustment coefficient is obtained according to the overall light exposure change; the adjustment coefficient is positively correlated with the overall light exposure change; The initial disturbance step size is adjusted according to the adjustment coefficient.

8. The control method for photovoltaic inverter power supply according to claim 1, wherein: The control method applicable to the photovoltaic inverter power supply further includes: When the light fluctuation degree does not satisfy the second condition, an adjustment coefficient is obtained according to the total current change speed; the adjustment coefficient is positively correlated with the total current change speed; The initial disturbance step size is adjusted according to the adjustment coefficient.

9. A control system suitable for a photovoltaic inverter power supply, characterized by comprising: Memory and processor; The memory is connected to the processor; The memory is used to store program instructions; The processor is configured to implement the control method applicable to a photovoltaic inverter power supply according to any one of claims 1 to 8 when the program instructions are executed.

10. A control device suitable for photovoltaic inverter power supply, characterized in that: The invention comprises a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the control method for a photovoltaic inverter power supply according to any one of claims 1 to 8.

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