Photovoltaic grid-connected inverter overcurrent suppression method and system

Abstract

The application discloses a photovoltaic grid-connected inverter overcurrent suppression method and system, comprising: an inverter unit obtains corresponding circuit operation state parameters and prestored transient event characteristics for matching, generates a transient matching result, and in response to the transient matching result representing a light mutation transient, generates first circuit regulation parameters based on the circuit operation state parameters and the matched light mutation transient characteristics to suppress the current of the inverter unit by a given amount and generates a first suppression result; generates light mutation reporting information and sends the light mutation reporting information and the first suppression result to adjacent inverter units, so that the adjacent inverter units generate second circuit regulation parameters based on the light mutation reporting information, the first suppression result and the circuit operation state parameters of the adjacent inverter units. The application can realize early perception and collaborative suppression of the overcurrent risk of the inverter unit in the light mutation transient scene, and solve the problem of overcurrent suppression action lag in the prior art.

Description

Technical Field

[0001] This application relates to the field of overcurrent suppression technology for photovoltaic grid-connected inverters, and in particular to a method and system for overcurrent suppression of photovoltaic grid-connected inverters. Background Technology

[0002] In a grid-connected photovoltaic (PV) power generation system, the grid-connected inverter is responsible for converting DC power from the PV side into AC power that conforms to grid connection specifications and outputting it to the grid. Its operation requires meeting strict safety and grid connection constraints in terms of current amplitude, rate of change, and voltage stability. When the input power from the PV side or the system operating conditions change rapidly, key operating parameters of the inverter, such as grid-connected current, DC bus voltage, and modulation, are prone to transient fluctuations. This can lead to sudden current surges, violent fluctuations in bus voltage, or even approaching or exceeding the device's safe operating limits, creating overcurrent risks. Therefore, in a grid-connected PV system, appropriate overcurrent suppression control strategies are typically required to address potential transient overcurrent issues during inverter operation, ensuring the inverter's safety, grid connection stability, and long-term reliable system operation.

[0003] In practical engineering applications, such as centralized photovoltaic power plants and distributed photovoltaic arrays, cloud shadowing is one of the typical high-frequency scenarios that can trigger the aforementioned overcurrent risks. Specifically, when a cloud moves across the photovoltaic array, the irradiance intensity will rapidly decrease and recover within a short period of time, causing frequent fluctuations and repetitive oscillations in the output power of the photovoltaic side. When cloud shadows pass by rapidly, existing overcurrent suppression schemes based on fixed threshold triggering mainly rely on current, voltage, or power anomalies reaching a set threshold before implementing current limiting or load reduction control. Due to the influence of measurement, filtering, and judgment logic, their suppression actions often have inherent lag. At the same time, under different cloud shadow intensities and repeated cloud shadow conditions, this type of fixed parameter control strategy is prone to frequent switching between current limiting and current release, which can lead to control jitter problems such as fluctuating current setpoints and increased grid-connected current fluctuations, affecting the operational stability and power generation efficiency of the photovoltaic power plant. Summary of the Invention

[0004] This application provides a method to achieve early detection and coordinated suppression of overcurrent risk in inverter units under transient scenarios of sudden changes in illumination, thereby at least solving the problems of delayed overcurrent suppression, difficulty in adapting fixed control parameters to different transient intensities, and jitter in the control switching of multiple inverter units in the prior art.

[0005] On the one hand, this application provides an overcurrent suppression method for a photovoltaic grid-connected inverter, applied to multiple interconnected inverter units, including: The inverter unit acquires the corresponding circuit operating status parameters and extracts the operating status associated indication information. It then matches the operating status associated indication information with the pre-stored transient event characteristics to generate a transient matching result. In response to the transient matching result being characterized as a sudden change in illumination transient, the inverter unit generates a first circuit control parameter based on the circuit operating state parameters and the matched sudden change in illumination transient characteristics to at least suppress the current setpoint of the inverter unit and generate a first suppression result. The inverter unit generates illumination mutation notification information based on the transient illumination mutation, and sends the illumination mutation notification information and the first suppression result to the adjacent inverter unit; In response to the adjacent inverter unit receiving a light change notification and a first suppression result, the adjacent inverter unit generates a second circuit control parameter based on the light change notification, the first suppression result, and the circuit operating state parameters of the adjacent inverter unit to at least suppress the current setpoint of the adjacent inverter unit.

[0006] On the other hand, this application also provides a photovoltaic grid-connected inverter overcurrent suppression system, applied to multiple interconnected inverter units, the system comprising: The operation status indication module is used to obtain the circuit operation status parameters corresponding to the inverter unit and extract the operation status related indication information. It matches the operation status related indication information with the pre-stored transient event characteristics to generate transient matching results. The first circuit control module is used to respond to the transient matching result being characterized as a sudden change in illumination, and then, based on the circuit operating state parameters and the matched sudden change in illumination transient characteristics, generate first circuit control parameters to at least suppress the current setpoint of the inverter unit and generate a first suppression result. The event notification module is used to generate light change notification information based on the light change transient, and send the light change notification information and the first suppression result to the adjacent inverter unit; The second circuit control module is used to respond to the light change notification information and the first suppression result received by the adjacent inverter unit, and then generate the second circuit control parameters based on the light change notification information, the first suppression result and the circuit operation state parameters of the adjacent inverter unit to at least suppress the current setpoint of the adjacent inverter unit.

[0007] This application provides a photovoltaic grid-connected inverter overcurrent suppression method and system. By constructing a matching mechanism of "operating status associated indication information - pre-stored transient event characteristics," it achieves the identification, classification, and transient analysis of typical transients such as sudden changes in illumination. This allows the inverter unit to perceive the transient evolution trend in advance before the current exceeds the limit or the protection is triggered, thereby transforming overcurrent suppression from the traditional "post-trigger type" to "early perception type based on transient analysis." This reduces the risk of current spikes and severe DC bus voltage fluctuations caused by detection lag under conditions of rapid illumination fluctuations such as cloud cover and shading. Furthermore, after completing the transient analysis, a first circuit control is generated based on the circuit operating status parameters and the matched transient characteristics. The parameters enable adaptive suppression of sudden changes in illumination of varying intensities and rates, reducing insufficient suppression or excessive load reduction issues caused by fixed amplitude / slope. Furthermore, by transmitting transient information on sudden illumination changes and the first suppression result to adjacent inverter units, and enabling adjacent inverter units to generate second circuit control parameters in advance and enter a pre-control state, the spatially ordered characteristics of cloud shadow propagation are utilized to achieve coordinated suppression of multiple inverter units, reducing the adjustment delay of subsequent units. This reduces the risk of continuous overcurrent triggering, frequent control switching, and overall operational fluctuations when multiple unit stations experience cloud shadow "passing by" in succession, thereby significantly improving the stability, continuity, and overall grid-connected power quality under scenarios of rapid illumination fluctuations. Attached Figure Description

[0008] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 This is a schematic diagram illustrating the application environment of an overcurrent suppression method for a photovoltaic grid-connected inverter, as provided in an embodiment of this application. Figure 2 A flowchart of an overcurrent suppression method for a photovoltaic grid-connected inverter provided in this application embodiment; Figure 3 This application provides a schematic diagram of a photovoltaic array under cloud shadow shading. Figure 4 This is a block diagram of an overcurrent suppression system for a photovoltaic grid-connected inverter, provided as an embodiment of this application. Detailed Implementation

[0010] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0011] It should be noted that, in the description of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. The terms "first," "second," etc., in this application are used to distinguish similar objects and are not used to describe a specific order or sequence.

[0012] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0013] This application provides an overcurrent suppression method for photovoltaic grid-connected inverters, which can be applied to, for example... Figure 1 The application environment shown includes at least multiple photovoltaic arrays, multiple inverter units, multiple grid connection points, and a power grid. Each photovoltaic array is electrically connected to its corresponding inverter unit, and each inverter unit is electrically connected to the power grid through its corresponding grid connection point. The multiple inverter units establish communication connections through wired and / or wireless communication networks to form a collaborative control network, which is used to realize the linkage control of transient event reporting and overcurrent suppression strategies.

[0014] The photovoltaic array is a power generation unit formed by multiple photovoltaic modules connected in series and / or in parallel. It can be a centralized photovoltaic array, a string photovoltaic array, a distributed rooftop photovoltaic array, or a photovoltaic array with energy storage coupling. Its output side is electrically connected to the DC input terminal of the corresponding inverter unit through a DC combiner or string branch. The grid connection point is the electrical connection node between the grid connection side of the inverter unit and the AC side of the public power grid. It can be a low-voltage grid connection point, a medium-voltage grid connection point, or a medium-high voltage grid connection point connected via a step-up transformer. It is used to realize the grid-connected collection of the AC current output by the inverter unit and the detection of grid-connected electrical parameters. The power grid can be any one or more of the following: a public power system, a local microgrid, a park-level distribution network, or a multi-source collaborative power grid containing distributed power sources.

[0015] The inverter unit can be a centralized inverter, a string inverter, or a modular parallel inverter. Internally, it includes a power conversion module, a DC bus, a current / voltage sampling module, a control processing module, and a communication interface module. The control processing module can be implemented using a DSP, FPGA, ARM processor, or a combination thereof, and is used to execute the transient matching, regulation parameter generation, and suppression control logic of this application. The current / voltage sampling module is used to collect circuit operating status parameters such as the grid-connected current, DC bus voltage, and control loop state variables of the inverter unit, and provides these parameters to the control processing module to extract operating status-related indication information. The communication interface module is used to send and receive information on sudden changes in illumination and suppression results between the inverter units.

[0016] During operation, when the photovoltaic array corresponding to any inverter unit is affected by sudden changes in light intensity such as cloud shadow shading, the inverter unit first generates operation status association indication information based on the circuit operation status parameters it has collected, and matches the operation status association indication information with the pre-stored transient event characteristics to obtain a transient matching result. When the transient matching result is characterized as a sudden change in light intensity, the inverter unit further generates a first circuit control parameter based on its circuit operation status parameters and the matched transient characteristics of the sudden change in light intensity, performs suppression control on its own current setpoint and generates a first suppression result, and generates a sudden change in light intensity notification information containing information such as the direction of the sudden change in light intensity, the time of the event, and the unit identifier, and sends the sudden change in light intensity notification information and the first suppression result to one or more inverter units that are connected to it in communication and are adjacent in topology through the communication connection. After receiving the notification information of sudden change in light intensity and the first suppression result, the adjacent inverter unit generates the second circuit control parameters based on the notification information, the first suppression result and the circuit operation status parameters it has collected. Based on the second circuit control parameters, it performs pre-suppression control on its own current setpoint, thereby completing the overcurrent risk suppression in advance before the sudden change in light intensity propagates to the adjacent inverter unit. This realizes the coordinated transient suppression control among multiple inverter units, reduces the cascade overcurrent risk caused by sudden change in light intensity and improves the overall grid-connected stability of the system.

[0017] like Figure 2 As shown, this application provides an overcurrent suppression method for a photovoltaic grid-connected inverter, comprising: Step 201: The inverter unit obtains the corresponding circuit operating status parameters and extracts the operating status associated indication information. It then matches the operating status associated indication information with the pre-stored transient event features to generate a transient matching result. Step 202: In response to the transient matching result being characterized as a sudden change in illumination transient, the inverter unit generates a first circuit control parameter based on the circuit operating state parameters and the matched sudden change in illumination transient characteristics to at least suppress the current setpoint of the inverter unit and generate a first suppression result. Step 203: The inverter unit generates illumination mutation notification information based on the illumination mutation transient, and sends the illumination mutation notification information and the first suppression result to the adjacent inverter unit; Step 204: In response to the adjacent inverter unit receiving the light change notification information and the first suppression result, the adjacent inverter unit generates the second circuit control parameters based on the light change notification information, the first suppression result and the circuit operation state parameters of the adjacent inverter unit to at least suppress the current setpoint of the adjacent inverter unit.

[0018] Specifically, the photovoltaic grid-connected inverter overcurrent suppression method provided in this embodiment constructs a matching mechanism of "operating status associated indication information - pre-stored transient event characteristics" to identify, classify, and analyze typical transients such as sudden changes in illumination. This allows the inverter unit to perceive the transient evolution trend in advance before the current exceeds the limit or the protection is triggered, thereby transforming overcurrent suppression from the traditional "post-trigger type" to "early perception type based on transient analysis." This reduces the risk of current spikes and severe DC bus voltage fluctuations caused by detection lag under conditions of rapid illumination fluctuations such as cloud cover and shading. Furthermore, after completing the transient analysis, a first circuit adjustment is generated based on the circuit operating status parameters and the matched transient characteristics. By controlling parameters, adaptive suppression of sudden changes in illumination of varying intensities and rates is achieved, reducing insufficient suppression or excessive load reduction caused by fixed amplitude / slope. Furthermore, by transmitting transient information of sudden illumination changes and the first suppression result to adjacent inverter units, and enabling adjacent inverter units to generate second circuit control parameters in advance and enter a pre-control state, the spatially ordered characteristics of cloud shadow propagation are utilized to achieve coordinated suppression of multiple inverter units, reducing the adjustment delay of subsequent units. This reduces the risk of continuous overcurrent triggering, frequent control switching, and overall operational fluctuations when multiple unit stations are "passing by" cloud shadows, thereby significantly improving the stability, continuity, and overall grid-connected power quality under scenarios of rapid illumination fluctuations.

[0019] In one embodiment, the inverter unit acquires the corresponding circuit operating state parameters and extracts the operating state associated indication information, including: Obtain the circuit operating status parameters of the inverter unit; Among them, the circuit operation status parameters refer to a set of parameters that can characterize the grid-connected operation status and control status of the inverter unit. They are preferably obtained from the internal registers of the controller or the output of status quantities set in the inverter unit, including but not limited to: grid connection point voltage, grid connection current feedback (RMS / component), DC bus voltage, DC side power or current, power setpoint, PLL (Phase-Locked Loop) phase / frequency, controller internal voltage reference vector phase angle (or modulation reference voltage vector phase angle), modulation ratio, limiter output, PI (Proportional-Integral Controller) controller integral quantity, PWM duty cycle saturation flag, temperature / derating flag, and one or more of these parameters. Based on preset transient correlation indicators, the circuit operating state parameters are mapped to indicators to generate multiple transient correlation feature components. Among them, the preset transient correlation index refers to the set of indicators or mapping rules used to characterize the sensitivity of transient evolution. It preferably includes one or more of the following: rate of change indicators, deviation indicators, saturation risk indicators, and fluctuation energy indicators. It may also include power angle disturbance indicators, such as one or more of the following: phase offset amplitude, phase offset change rate, phase offset over-limit duration, phase swing energy, etc. Preferably, the index mapping can be achieved by: obtaining the rate of change by calculating the "adjacent sampling difference" of the original parameters within a preset sliding time window; obtaining the deviation by calculating the difference between the given value and the feedback value; generating the saturation proximity of the integral quantity to its upper and lower limits; and generating the fluctuation energy index by the variance or peak-to-peak value of the waveform within the window. Based on one or more operational transient associated feature components, a combined mapping is performed to generate an operational transient associated vector and determine it as operational status associated indication information; Here, the combination mapping refers to concatenating multiple feature components in a preset order or linearly combining them according to preset weights to form a vector; preferably, the weights can be equal, or higher weights can be assigned to feature components with higher event distinguishability through offline statistics; the dimension of the transient correlation vector is preferably 3 to 20.

[0020] Preferably, the preset transient correlation indicators can be provided by the equipment factory calibration or obtained by offline statistics based on historical transient samples; for example, the current feedback change rate, DC power change rate, DC bus voltage fluctuation energy, and saturation proximity can be selected as the main characteristic components, and the phase offset amplitude and / or phase offset change rate can be further selected as the main characteristic components to enhance the sensitivity to the coupling scenario of transient phase disturbance and overcurrent risk.

[0021] Specifically, in this embodiment, the circuit operating state parameters are mapped based on preset transient correlation indicators to obtain multiple transient correlation feature components. Furthermore, a transient correlation vector is formed by combining and mapping these components as operating state correlation indication information. This transforms the inverter unit's representation of transients from "direct participation of original parameters in judgment" to "characteristic expression oriented towards transient evolution." This enhances the sensitivity and consistency of the operating state to transient evolution processes such as sudden changes in illumination, reduces the interference of instantaneous fluctuations of individual parameters on the identification results, and improves the stability and reliability of subsequent transient matching and transient analysis.

[0022] In one specific embodiment, the inverter unit can also construct a transient power angle representation based on the phase state quantities available inside its control loop. The transient power angle representation is preferably the phase offset between the "internal reference voltage vector phase of the inverter unit" and the "grid-connected voltage phase". The grid-connected voltage phase is preferably obtained by the output of the phase-locked loop, and the internal reference voltage vector phase is preferably the reference voltage vector phase obtained by coordinate transformation of the voltage command output by the current control loop, or the reference voltage vector phase before entering the modulation module. The inverter unit can further obtain power angle disturbance characterization quantities such as the rate of change of phase offset, peak offset, offset duration, and phase swing energy, which are used to reflect the impact of phase offset on grid current overshoot, modulation saturation, and control stability margin during transient periods.

[0023] In one embodiment, a transient matching result is generated by matching the runtime status association indication information with pre-stored transient event characteristics, including: Based on preset transient evolution discrimination conditions and operating status related indication information, the corresponding inverter unit is determined to perform transient evolution trend judgment and obtain transient trend discrimination results; The preset transient evolution discrimination condition refers to the trigger threshold rule used to determine whether a transient evolution trend exists. It preferably includes one or more of the following: within the preset confirmation window, at least a few components in the running transient correlation vector continuously exceed their respective thresholds; or the overall strength of the running transient correlation vector continuously exceeds the threshold. The confirmation window is preferably 50 milliseconds to 500 milliseconds. The threshold can be set by offline statistical steady-state noise level, for example, taking a number of times the upper limit of steady-state fluctuation as the trigger threshold. In response to the transient trend discrimination result indicating that the inverter unit has a transient evolution trend, the operation state association indication information is analyzed to obtain the operation transient association vector of the inverter unit; A transient matching feature vector is generated based on pre-stored transient event features. The transient event features include at least one or more of the following: transient features of sudden changes in illumination and transient features of power grid disturbances. The pre-stored transient event features refer to event templates or sets of statistical features that can be used for online matching, preferably including one or more of the following: typical vector template, mean vector and dispersion parameter, and segmented stage template; preferably, the transient matching feature vector can be directly constructed from the above templates or constructed after extracting statistical features. Based on the preset matching criteria, the feature matching degree between the transient correlation vector and multiple transient matching feature vectors is determined respectively, and the transient event feature corresponding to the highest feature matching degree is determined as the highest matching transient event feature; Among them, the preset matching criteria refer to the similarity calculation rules, which preferably include one or more of "directional similarity", "distance similarity" and "time alignment similarity". Specifically, the matching degree can be obtained by standardizing the transient association vector and the template vector in the same dimension, calculating the degree of consistency between the two in the direction or the degree of closeness in numerical difference, and obtaining a similarity score between low and high. The matching confidence of the highest matching transient event feature is determined based on the highest feature matching degree, the proportion of effective components of the running transient correlation vector, and / or the difference between the highest and second highest feature matching degrees. Among them, the effective component ratio refers to the proportion of components that "significantly exceed the noise threshold" in the transient correlation vector of operation; the noise threshold can be determined by the steady-state historical fluctuation statistics; the matching confidence can be obtained by mapping the "highest matching degree", "effective component ratio" and "difference between the highest and second highest" to standardized scores respectively, and then combining them according to the weights preset by the user or historical reference data to obtain the confidence score. If the feature matching degree of the highest matching transient event feature is greater than or equal to the feature matching threshold, and the matching confidence degree is greater than or equal to the confidence threshold, then a transient matching result representing the transient event type corresponding to the highest matching transient event feature is generated. The feature matching threshold and confidence threshold are preferably set by balancing the false alarm rate and false negative rate of offline samples. For example, when there are enough samples, a combination of thresholds that makes the false alarm rate lower than a preset target (such as 1% to 5%) can be selected; when there are insufficient samples, a more conservative threshold can be used to reduce false triggering. If the feature matching degree of the highest matching transient event feature is less than the feature matching threshold, or the matching confidence degree is less than the confidence threshold, then a transient matching result representing that the transient event is not matched is generated.

[0024] Specifically, in this embodiment, by introducing transient evolution trend determination, the presence of a transient evolution trend in the inverter unit is determined before matching. If an evolution trend exists, feature vector analysis and matching calculation are performed. Simultaneously, the feature matching degree is obtained based on a preset matching criterion, and a matching confidence degree is formed by combining the proportion of effective feature components and the difference between the highest and second-highest matching degrees. The transient matching result of "matched / unmatched" is determined by the matching degree threshold and the confidence threshold. This enables transient identification to have a complete closed loop of "trend triggering - matching judgment - confidence filtering - unmatched fallback". This reduces the probability of misjudging non-transient fluctuations as typical transients and avoids hastily triggering suppression strategies when features are insufficient or similar events are confused. This improves the ability to distinguish different event types such as sudden changes in illumination transients and power grid disturbance transients and enhances engineering robustness.

[0025] In one embodiment, before matching the runtime association indication information with pre-stored transient event characteristics, the method further includes: The system acquires historical circuit operation status parameters of multiple inverter units, historical photovoltaic operation parameters of multiple photovoltaic units connected to the inverter units, and historical scene data, which includes at least historical weather event information and historical power grid event information. Among them, the historical photovoltaic operating parameters preferably include string voltage / current, array power, irradiance (if a sensor is configured), and module temperature; the historical weather event information preferably includes one or more of the following: cloud cover changes, irradiance abrupt change records, and rainfall / strong wind records; the historical power grid event information preferably includes one or more of the following: voltage drop / rise, frequency disturbance, fault waveform triggering records, and dispatch switching records. Based on a preset time window, the historical circuit operation status parameters and historical photovoltaic operation parameters are segmented to obtain multiple sets of operation parameters for historical segments; The preset time window is used to form discernible short time segments, preferably 0.2 seconds to 5 seconds; the segmentation method can be a sliding window or a non-overlapping window, and the sliding step size is preferably 10 milliseconds to 200 milliseconds; Based on preset transient correlation indicators, the operation parameter sets of multiple historical segments are processed to generate operation indicator sets of multiple historical segments. The operational index set refers to the set of multi-dimensional indicators calculated for each segment. Specifically, the operational index set can be obtained by statistically analyzing the peak rate of change, fluctuation energy, deviation amplitude, and proportion of saturation indicators of parameters such as current, power, and voltage within each segment to form the index set for that segment. If the set of operating indicators meets the preset transient evolution discrimination conditions, the corresponding historical segment is determined as a transient segment, and the corresponding set of operating parameters is determined as a transient parameter set. Based on the time periods corresponding to multiple transient segments, event types with preset time correlations to transient segments are sequentially filtered from historical weather event information and historical power grid event information to obtain a set of scene-related events. Here, preset time correlation refers to the proximity or overlap between the event occurrence time and the transient segment time period. Preferably, it can be set that "the event occurrence time falls within a certain number of seconds before or after the transient segment to determine correlation". The "several seconds" can be set according to the event recording granularity, such as 1 second, 5 seconds or 60 seconds. Based on event type, the set of scene-related events is classified and aggregated to obtain multiple subsets of scene-related events; Based on multiple transient parameter sets corresponding to the subset of scene-related events, generate a transient sample set of events and determine the intrinsic similarity of the transient sample set of events; Intrinsic similarity refers to the degree of aggregation of multiple transient samples under the same event type in the feature space. Specifically, intrinsic similarity can be obtained by converting each transient sample into a feature vector of a uniform dimension, and then calculating the average similarity between samples or the degree of dispersion within a class. When samples show "high similarity or low dispersion", the event type is considered to have a stable transient form. If the intrinsic similarity of the event transient sample set is greater than or equal to a preset similarity threshold, the corresponding event type is determined to be a transient associated event type, and statistical features are extracted from the event transient sample set to obtain the event transient sample features. The similarity threshold can be set through offline sample statistics, such as requiring "average similarity to reach a preset lower limit" or "intra-class dispersion to be lower than a preset upper limit"; statistical feature extraction can include mean features, quantile features, peak values ​​and peak occurrence time, segmented stage templates, etc.; the distribution method can be achieved through intra-site LAN broadcast or centralized distribution by the main control, and the update cycle can be configured by day / week / month. Transient event features are generated based on the transient correlation event type and transient sample features, and then distributed to multiple inverter units to generate transient matching results.

[0026] Specifically, in this embodiment, by utilizing historical operating data of multiple inverter units, photovoltaic operating data, and historical scenario data including weather events and grid events, the system first segments the data by time window and calculates the set of operating indicators for historical segments based on transient correlation indicators. Then, transient segments are filtered using transient evolution discrimination conditions. Within the corresponding time period of the transient segments, event types with time correlation are selected from historical scenario events, classified and aggregated, and sample similarity is checked. Statistical features are then extracted from samples that meet the similarity requirements to form transient event features, which are then distributed to each inverter unit. This ensures that the pre-stored transient event feature library originates from real scenarios and verifiable sample aggregation results, thereby improving the representativeness and transferability of the feature library, reducing the bias caused by manually constructed features, enhancing the accuracy and consistency of online matching, and enabling the system to better adapt to transient morphological changes under different sites, seasons, or operating conditions.

[0027] In one specific embodiment, generating transient event features based on transient associated event types and transient event sample features further includes: In response to the transient correlation event type being a sudden illumination event, shadow intensity feature parameters representing the shading intensity are extracted based on the transient sample features of the event. Shadow intensity feature parameters include, for example, power drop amplitude, grid current change rate, DC side voltage / current disturbance amplitude and duration. Based on the transient sample features of the event, power angle risk characteristic parameters related to power angle disturbance are extracted. The power angle risk characteristic parameters include at least one or more of the following: phase offset amplitude, peak phase offset change rate, peak phase offset, phase swing energy, and / or phase offset over-limit duration. By fusing and mapping shading characteristic parameters with power angle risk characteristic parameters, a transient level of illumination change (e.g., Level I / II / III or light / medium / heavy shading) is obtained. The transient level and / or power angle risk characteristic parameters are used as part of the transient event characteristics for the adaptive generation of subsequent circuit control parameters and the selection of suppression intensity. This ensures that when the shading degree is higher and / or the power angle disturbance is more severe, the corresponding amplitude limiting threshold, slope limiting intensity, anti-saturation weight or suppression weight is greater, and / or the start-up advance is greater, thereby improving the suppression accuracy and economy under different shading degrees and different phase disturbance levels.

[0028] In one embodiment, the inverter unit generates first circuit control parameters based on circuit operating state parameters and matched transient characteristics of sudden changes in illumination, including: Based on the transient characteristics of sudden changes in illumination, the corresponding transient sample characteristics of sudden changes in illumination are determined; among them, the transient sample characteristics of sudden changes in illumination preferably include "stage division characteristics" and "typical change amplitude / change rate characteristics within the stage" to support subsequent stage determination and short-term prediction. Align the circuit operating state parameters with the transient sample characteristics of sudden light changes to determine the current transient stage parameters of the inverter unit. Among them, state alignment refers to comparing the currently observed feature change pattern with the sample template in terms of stage features to determine which stage it is in; preferably, the stage determination can be done in the following ways: comparing whether the current rate of change, deviation amplitude, fluctuation energy and other indicators fall within the typical range of the template stage, and the stage that falls the most is the current stage; or calculating the similarity with each stage template within a short window and selecting the stage with the highest similarity. Based on the current transient stage parameters and the characteristics of transient samples of sudden illumination changes, the subsequent operating state of the inverter unit in the preset prediction time domain is predicted, and the predicted operating state parameters are generated. The preset prediction time domain is preferably 20 milliseconds to 200 milliseconds, or set to several times the typical response time of the current loop. Specifically, the predicted operating state parameters can be obtained in the following way: at the current stage, based on the "typical change trend" given by the sample template, the current / power / bus voltage and other states in the future short period of time are predicted, and the predicted values ​​are subject to constraints that do not exceed the grid connection limit and control capability. Based on the predicted operating state parameters, multiple circuit risk items and corresponding circuit risk indicators are determined, and based on the multiple circuit risk items and corresponding circuit risk indicators, multiple control items of the inverter unit are determined. The circuit risk items preferably include one or more of the following: grid current over-limit risk, control saturation risk, DC bus overvoltage / undervoltage risk, and phase-locked loop disturbance risk. Transient power angle disturbance risk may also be included. The transient power angle disturbance risk is preferably characterized by indicators such as phase offset amplitude, peak phase offset rate of change, and duration of phase offset over-limit, used to reflect the impact of rapid phase oscillation on current overshoot, modulation saturation, and control stability margin. The risk indicators are preferably obtained through "margin of predicted value relative to limit," "margin of predicted rate of change relative to allowable rate of change," and "probability or duration of saturation indicator occurrence." Based on preset coordination rules, multiple control items are coordinated and integrated to generate the first circuit control parameters; The preset coordination rules can be set through factory calibration or simulation scanning; preferably, the coordination rules include at least the following: safety-related control items (such as amplitude limiting / anti-saturation) take precedence over performance-related control items (such as recovery slope optimization); when multiple items are triggered simultaneously, a more conservative limit or a stricter slope limit is selected as the final constraint; when the predicted risk is eliminated, the recovery rules can be gradually withdrawn.

[0029] Preferably, when the transient power angle disturbance risk index characterizes phase shift or its rate of change exceeding a preset threshold, the preset coordination rules further include: increasing the slope limit strength of the current setpoint and / or reducing the amplitude limit threshold, increasing the anti-saturation processing weight or extending the recovery slope limit window, and appropriately shifting the suppression effective window forward to suppress current spikes and saturation de-emergence impacts caused by power angle disturbance coupling.

[0030] Specifically, in this embodiment, a chain generation logic of "transient sample characteristics - operating state alignment - transient stage determination - prediction of subsequent operating state - risk item identification - control item selection - coordination and integration" is introduced when generating the first circuit control parameters. This makes the suppression control no longer rely solely on passive restrictions on the current instantaneous state, but combines the transient stage and short-term evolution prediction to expose potential risks in advance and select control items. Then, it is comprehensively integrated through coordination rules, thereby improving the targeting of control parameters to different light change intensities and evolution rates, reducing insufficient suppression caused by fixed strategies or response lags, and also reducing unnecessary over-intervention, taking into account both safety margin and power generation efficiency.

[0031] In one embodiment, suppressing the current setpoint of the inverter unit and generating a first suppression result includes: Analyze the circuit operating state parameters of the inverter unit to determine at least the current setpoint, current limiting related quantities, and control saturation related quantities of the inverter unit. Among them, the current limiting related quantities preferably include one or more of the following: grid-connected current limit, limiter output status, synthetic current amplitude indication, and component current amplitude indication; the control saturation related quantities preferably include one or more of the following: modulation ratio close to saturation value, PWM saturation flag, PI integral close to upper and lower limits, and anti-saturation back-calculation / freeze status; the above related quantities can preferably be directly read from the controller's internal status quantities; Based on the matched transient characteristics of illumination change, determine the direction parameters of illumination change; The illumination change direction parameter is the event direction label or direction classification result corresponding to the matched illumination change transient feature, used to characterize the direction of illumination intensity change (rising / falling) or the direction of equivalent input power change. Preferably, the direction parameter can be given by the event transient sample features in the feature library, such as the sample features containing "DC side power change trend label", "current given change trend label" or "monotonicity label of stage template". In a further implementation, the direction given by the sample features can also be used as the main criterion, and the DC power change direction within the local short window can be used as the consistency check to avoid direction misjudgment caused by noise. The first circuit control parameters are analyzed to generate a set of current control parameters to control the current setpoint of the inverter unit. The set of current control parameters includes at least one or more of the following: slope limit parameter, amplitude limit threshold, over-limit judgment threshold, enhancement suppression parameter, anti-saturation parameter in the downward direction, current limit parameter, and recovery slope limit parameter. In response to the change in illumination direction parameter representing the increase in illumination intensity, the rising slope index of the current setpoint is constrained according to the slope limiting parameter, and the amplitude index of the current setpoint is constrained according to the amplitude limiting threshold, thus generating the current setpoint after initial suppression. Based on the current given after initial suppression and combined with the circuit operating state parameters, the predicted quantity of the inverter unit is determined. The predicted quantity includes at least one or more of the following: predicted peak output current and predicted rate of change of current. The generation of the prediction is preferably based on the "event transient sample features corresponding to the matched transient features of light mutation" to make the prediction consistent with the event type, transient stage and typical evolution law; The predicted quantity is compared with the over-limit judgment threshold to obtain the over-limit judgment result. If the over-limit judgment result indicates an over-limit, then the enhanced suppression processing is applied to the initially suppressed current setpoint according to the enhanced suppression parameter to obtain the suppressed current setpoint. The over-limit judgment threshold is preferably given by the first circuit control parameter, or set by the grid current limit combined with the reserved margin; the reserved margin can be set to a more conservative or more aggressive level based on the equipment's short-term overload capacity, grid connection specification requirements, or historical overcurrent statistics. In response to the light intensity decrease characterized by the direction parameter of the sudden change in illumination, a control saturation risk judgment result is generated based on the control saturation related quantity and combined with the anti-saturation parameter, and a synthetic current over-limit risk judgment result is generated based on the current limit related quantity and combined with the current limit parameter. If the control saturation risk assessment result indicates that the inverter unit has a control saturation risk, then according to the anti-saturation parameter and / or recovery slope limit parameter, the current setpoint is subjected to a process to suppress the control saturation release shock. The process includes at least one of the following: performing anti-saturation processing on the current setpoint and applying a recovery slope limit to the rate of change index of the current setpoint to suppress the sudden change in the current setpoint caused by the release of control loop saturation. If the result of the synthetic current over-limit risk assessment indicates that the inverter unit has a synthetic current over-limit risk, then the current setpoint is subjected to a limiting process according to the current limit parameter. The limiting process includes at least one of the following: limiting the synthetic current vector amplitude index and limiting the component current setpoint to obtain the suppressed current setpoint. Preferably, to maintain consistency with the sample feature chain, the determination of control saturation risk and the triggering of recovery constraints in the descent direction can refer to the "relief shock risk label" or "recovery segment change rate range" in the transient sample features of the event to determine whether a stricter recovery slope limit window and intensity are needed; in practice, this can be manifested as follows: when the sample features indicate that this type of descent event is prone to saturation relief shock, the recovery window is set to be longer or the recovery slope is set to be more conservative; One or more current control parameters used in the current control parameter set are determined as suppression action parameters, and the first suppression result of the inverter unit is generated based on the suppression action parameters and the current setpoint after suppression.

[0032] Preferably, the predicted amount can be obtained in the following ways: Extract inference criteria such as "typical rate of change level", "typical peak arrival trend" and "stage duration range" corresponding to the current transient stage from the transient sample characteristics of the event; By combining local circuit operating status parameters (such as current grid current feedback level, current setpoint, grid current margin, and control bandwidth capability) to adapt and correct the above typical trends, a prediction of the current change rate and the peak level that may be reached in the short term is obtained. Among them, the "preset prediction time domain" is preferably matched with the stage duration range in the transient sample characteristics of the event, and can be truncated or shortened according to the current loop response time to avoid over-extrapolation.

[0033] It is worth noting that in this embodiment, whether the sudden change in light intensity is in the upward or downward direction, it may induce the risk of overcurrent on the grid-connected side, thus requiring the triggering of overcurrent suppression. However, the risk mechanisms and suppression focuses of the two are different: When the irradiance increases, the available power of the photovoltaic array increases rapidly, and the active current setpoint of the inverter is usually increased accordingly. Under the combined effect of current loop response, PLL phase tracking, DC bus energy balance, and outer loop power regulation, the increase in current setpoint may be characterized by a steep rise or accompanied by transient overshoot, causing the grid-connected current to approach or exceed the grid-connected current limit in a short period of time, forming a typical "rising impulse overcurrent risk". Therefore, in the rising direction, it is preferable to apply slope limitation and amplitude limitation to the current setpoint, and trigger enhanced suppression when "the peak overshoot trend" is obtained based on transient sample characteristics to suppress current spikes and overshoot. Regarding the direction of decreasing light intensity, although the reduction in active power input tends to lower the steady-state current level, overcurrent risks may still occur during transient processes. On the one hand, a sudden drop in power can disrupt the energy balance between the DC and AC sides, potentially leading to regulation lag and state accumulation between the voltage / power outer loop and the current inner loop. This is especially true when the system was previously operating under high load or near modulation limits, where the controller integral and limiter states may enter or approach saturation. When the light intensity decreases and triggers a target reduction, the moment the control loop is released from saturation may produce a "release shock," manifested as a sudden change and oscillation in the current setpoint or current component, thus causing a short-term overcurrent risk. Within a short period of time, a peak current is formed; on the other hand, a decrease in illumination is often accompanied by a redistribution of current components (e.g., a rapid drop in the active component and a relative increase in the proportion of reactive or compensating components). Under the coupling effect of grid impedance and voltage disturbance, the amplitude of the synthesized current may still surge in a short time and trigger the limit risk. Based on the above mechanism, the suppression strategy in the downward direction needs to cover both the "sudden change risk caused by the release of control saturation" and the "risk of synthesized current exceeding the limit". Therefore, it is preferable to introduce anti-saturation treatment, slope limitation in the recovery phase, and amplitude limiting treatment of synthesized current / component current to suppress overcurrent peaks and improve control smoothness in the power drop scenario.

[0034] Specifically, in this embodiment, the first circuit control parameters are analyzed into a set of current control parameters, and differentiated suppression paths are adopted according to the direction of sudden changes in illumination: in the direction of enhanced illumination, the slope and amplitude of the given current change process are jointly constrained, and enhanced suppression is further triggered when an over-limit trend is predicted; in the direction of weakened illumination, the constraints of anti-saturation treatment, amplitude limiting treatment and recovery stage are adopted in combination with the control saturation risk and the current over-limit risk, so that the suppression strategy can cover the two typical problems of "rising impact type overcurrent risk" and "falling release type impact risk", thereby reducing current spikes and sudden change risks caused by saturation release, and improving the effectiveness and smoothness of the suppression action under transients in different directions, reducing frequent control jitter and operation fluctuations.

[0035] In one embodiment, the inverter unit generates illumination change notification information based on the transient illumination change, and sends the illumination change notification information and the first suppression result to the adjacent inverter unit, including: Based on the transient state of illumination change, at least the illumination change direction parameters and the event start time parameters of the corresponding illumination change event should be determined. Among them, the event start time parameter refers to the timestamp when the change in illumination is determined to be the start, preferably the time when the transient trend determination is first triggered, or the time when the rate of change index first crosses the threshold; the timestamp is preferably generated by the controller's internal clock, and the resolution can be milliseconds or higher; The identifier corresponding to the inverter unit is determined as the notification source identifier; wherein, the notification source identifier is preferably the inverter communication node address, topology number or unique ID within the station; The illumination change direction parameter, the event start time parameter, and the notification source identifier are encapsulated to generate illumination change notification information; wherein, the notification sending time parameter refers to the actual time when the message is sent from the channel, which is used by the receiving side to estimate the link delay; preferably, the notification sending time parameter can be written by the communication driver when the message is framed. Analyze the first suppression result and determine the first suppression notification information. The first suppression notification information includes at least the current setpoint of the inverter unit after suppression and the corresponding suppression action parameters. The illumination mutation notification information and the first suppression notification information are optically encapsulated to generate a notification linkage message; wherein, the association encapsulation means placing the event field and the suppression result field in the same message body, or under the same transaction sequence number; preferably, the message sequence number or event number can be carried to support duplicate packet identification and out-of-order correction; Based on the communication connection relationship and topology distribution of multiple inverter units, one or more adjacent inverter units that are topologically adjacent to the inverter unit and have a communication connection relationship are identified. The notification and linkage message will be sent to one or more adjacent inverter units.

[0036] Specifically, in this embodiment, by encapsulating at least the direction of the sudden change in illumination, the start time of the event, and the identifier of the notification source in the notification information, and further parsing the first suppression result to form notification content containing information on the suppressed target and suppression action, and then encapsulating the two together into a notification linkage message, and selecting adjacent inverter units to send it according to the communication connection relationship and topology distribution, the information obtained by the adjacent inverter units includes both "event occurrence and direction" and "suppression results and reference actions already taken", thereby improving the operability and timeliness of the linkage information, reducing the ineffective pre-control caused by blind or delayed responses of adjacent inverter units, and enhancing the coordination consistency and overall stability in multi-unit cascade scenarios.

[0037] In one embodiment, adjacent inverter units generate second circuit control parameters based on illumination change notification information, first suppression results, and circuit operating state parameters of adjacent inverter units, including: Parse the illumination change notification information to obtain the illumination change direction parameters, event start time parameters, and notification source identifier of the illumination change event, and obtain the notification sending time parameters carried in the illumination change notification information; Generate information reception time parameters based on the time when adjacent inverter units receive notifications of sudden changes in illumination. Based on the information reception time parameter and the notification transmission time parameter, the link transmission delay parameter between adjacent inverter units is generated; wherein, the link transmission delay parameter is preferably obtained by subtracting the "notification transmission time" carried in the message from the "information reception time" recorded by the adjacent inverter unit to obtain the one-way transmission delay estimate; if there is clock asynchrony, it is preferable to use intra-station time synchronization or correct it with a fixed offset obtained from multiple statistics; Based on the notification source identifier and the communication connection relationship and topology distribution of multiple inverter units, the propagation path parameters of the illumination change event from the notification source inverter unit to the adjacent inverter unit are determined. The propagation path parameters include at least: path distance parameters and path order parameters. Among them, the path series parameter refers to the number of topology hops traversed from the reporting source to this unit; the path distance parameter is preferably obtained through inverter layout coordinates or array arrangement information, such as by using an approximation method of multiplying the distance between adjacent inverter units by the number of hops, or by using the projected distance along the array direction. The event notification interval parameter is generated based on the notification sending time parameter and the event start time parameter. The event notification interval parameter is then corrected for delay based on the information receiving time parameter and the link transmission delay parameter to obtain the local equivalent time parameter for the start of the event. Specifically, the local equivalent time parameter can be obtained in the following way: first calculate the time interval between the event start time and the notification sending time, then subtract the time interval and the link transmission delay from the local reception time, thereby mapping the event start time to the local time base and obtaining the local equivalent event start time. Based on the propagation model parameters and propagation path parameters obtained from the statistics of historical illumination change events, the propagation time parameters are determined. Based on the local equivalent time parameter of the event start and the propagation time parameter, the expected arrival time parameter of the illumination change event is determined. Among them, the propagation model parameters are the average propagation speed parameters or the average single-hop propagation delay parameters. The propagation time parameter can be obtained in the following ways: if the average propagation speed is used, the propagation time is calculated by combining the propagation path distance with the average propagation speed; if the average single-hop propagation delay is used, the propagation time is calculated by combining the propagation path series with the single-hop delay; the expected arrival time parameter can be obtained by superimposing the propagation time onto the local equivalent event start time; the average propagation speed and average single-hop propagation delay can be obtained from historical cloud shadow events; under default conditions, it can also be initialized according to an empirical range, for example, the cloud shadow propagation speed is set in the range of several meters per second to tens of meters per second, and rolled correction is performed in subsequent deviation calibration embodiments; The start-up advance parameter is determined based on the expected arrival time parameter and the current loop response time parameter of the adjacent inverter unit, and the circuit control start-up time parameter is determined based on the start-up advance parameter. The start-up advance parameter can also be adaptively corrected based on transient level and / or power angle risk characteristic parameters: when the transient level or power angle risk is higher, the start-up advance is increased to ensure that current limiting, anti-saturation and modulation margin protection are completed before the expected arrival time; when the transient level and power angle risk are lower, a smaller start-up advance is allowed to reduce unnecessary early load reduction. The current loop response time parameter can be obtained by bandwidth conversion or step response calibration; the start advance is preferably set to several times the current loop response time to ensure that the pre-suppression entry and parameter readiness are completed before the arrival time. Analyze the first suppression result to obtain the current setpoint of the notification source inverter unit after suppression and the corresponding suppression action parameters; The reference current control target of the adjacent inverter unit is determined based on the suppressed current setpoint, and the reference current control parameter of the adjacent inverter unit is determined based on the suppression action parameter and the circuit operation state parameter of the adjacent inverter unit. Based on the circuit control start-up time parameters, the reference current control target quantity, the reference current control parameters, and the circuit operation status parameters of the adjacent inverter units, the second circuit control parameters of the adjacent inverter units are generated.

[0038] Specifically, in this embodiment, by comprehensively processing the notification message on the side of adjacent inverter units to consider the time delay and propagation link, the inverter units can capture the spatially ordered characteristics of the cloud shadow propagation "passing by one after another" through information interaction. Under this characteristic, a pre-regulation closed loop of "time synchronization - prediction - early start - reference alignment" is realized, thereby significantly shortening the effective response time when the transient state arrives, reducing the coordination mismatch caused by communication delay and propagation differences, and reducing the risk of continuous overcurrent in cascaded units and the overall fluctuation caused by control switching.

[0039] In one embodiment, based on the circuit control start-up time, the reference current control target amount, the reference current control parameters, and the circuit operating state parameters of the adjacent inverter units, a second circuit control parameter for the adjacent inverter unit is generated, including: Analyze the circuit operation status parameters of adjacent inverter units to determine the grid connection point voltage parameters, DC bus voltage parameters, grid connection current feedback effective value parameters, grid connection current limit parameters, current loop bandwidth parameters, and grid connection side equivalent impedance estimation parameters of adjacent inverter units. The grid current margin parameter is generated based on the grid current feedback effective value parameter and the grid current limit parameter. The target correction coefficient is determined by the grid current margin parameter according to the preset target mapping relationship, and the target correction coefficient is limited to the preset coefficient range. Specifically, the grid-connected current margin parameter can be obtained as follows: the "remaining margin" between the grid-connected current limit and the current grid-connected current feedback is used as a metric and normalized to a ratio; the target correction coefficient can be obtained through a preset target mapping relationship: when the margin is small, a smaller coefficient is given to reduce the reference target, and when the margin is large, the coefficient approaches 1 to maintain the reference target; the preset coefficient range can be set to 0.6 to 1.0 or a more conservative range, which can be determined by the equipment rating and grid connection specifications. Based on the target correction coefficient, a scaling operation is performed on the reference current control target quantity to obtain the refined current control target quantity; By pre-setting the slope mapping relationship, the slope correction coefficient is determined based on the current loop bandwidth parameter. The slope correction coefficient can be obtained in the following ways: the rate of change capability is determined based on the size of the current loop bandwidth, and the higher the bandwidth, the greater the allowable slope; the preset slope mapping relationship can be obtained by factory calibration or simulation scanning, and upper and lower limits are applied to the results to prevent them from being too large or too small; The current slope limit parameter and recovery slope parameter are obtained by analyzing the reference current control parameter, and the current slope limit parameter and recovery slope parameter are scaled based on the slope correction coefficient to obtain the slope refinement parameter; The threshold correction coefficient is determined based on the grid-connected side equivalent impedance estimation parameters by using a preset threshold mapping relationship. The threshold correction coefficient can be obtained in the following ways: the sensitivity of current change to voltage fluctuation is determined based on the estimated equivalent impedance of the grid-connected side; the larger the impedance, the more conservative the threshold setting. The preset threshold mapping relationship can be obtained by the grid-connected impedance grading. The amplitude limiting threshold parameter and the over-limit judgment threshold parameter are obtained by analyzing the reference current control parameters. Then, based on the threshold correction coefficient, a scaling operation is performed on the amplitude limiting threshold parameter and the over-limit judgment threshold parameter to obtain the threshold refinement parameter. The target current regulation target quantity is subjected to target limiting processing to limit the target current regulation target quantity within the target range determined by the grid-connected current limit parameter, thereby obtaining the second current regulation target quantity; Slope limiting processing is performed on the slope refinement parameters to limit the current slope limiting parameters and the recovery slope parameters within the slope range determined by the pre-stored slope boundary table, thus obtaining the second current slope control parameters. The pre-stored slope boundary table refers to the set of upper and lower limits of the slope allowed under different capacity levels, filter parameters and grid-connected voltage levels; preferably, the slope boundary table can be obtained by factory type test, simulation scan or grid-connected test calibration; for example, the upper limit of the rising slope can be set to a certain range of the rated change rate, and the upper limit of the recovery slope can be set to a small proportion of the rising slope to improve the recovery smoothness. Threshold limiting processing is performed on the threshold refinement parameters to limit the amplitude limiting threshold parameters and the over-limit judgment threshold parameters to a threshold range consistent with the grid-connected current limit parameters, thereby obtaining the second current amplitude threshold control parameters; The circuit control start-up time parameter, the second current control target quantity, the second current slope control parameter, and the second current amplitude threshold control parameter are combined as the second circuit control parameters of the adjacent inverter unit.

[0040] Furthermore, adjacent inverter units can generate additional correction coefficients based on the locally detected phase offset amplitude and / or phase offset change rate during the pre-regulation preparation stage, and use these additional correction coefficients to further scale the slope refinement parameters and / or threshold refinement parameters: when the power angle disturbance is more severe, the current slope limit is made more conservative and / or the limiting threshold is made more conservative to reduce the risk of current overshoot caused by rapid phase swing; when the power angle disturbance is weak, a smaller additional correction is allowed to balance power generation efficiency and control smoothness.

[0041] Specifically, in this embodiment, a refined correction mechanism based on local grid-connection margin, control response capability, and grid-connection equivalence is introduced when generating the second circuit control parameters. The reference control target, change process constraints, and judgment threshold are adaptively scaled, and further limited to a safe range consistent with local capability through target limiting, slope limiting, and threshold limiting. This ensures that adjacent inverter units do not simply copy the suppression settings of the reporting source, but rather implement them differently based on their own grid-connection conditions and response characteristics. This improves the adaptability and safety of the linkage suppression under different unit parameter differences and grid-connection condition differences, reduces the risk of insufficient suppression, excessive suppression, or operational instability caused by parameter mismatch, and further improves the station-level collaborative effect and grid-connected power quality.

[0042] In one embodiment, after generating the second circuit control parameters, the method further includes: The second circuit control parameters are analyzed to determine the circuit control start time parameters. At the corresponding circuit control start time, the second suppression processing is performed on the current setpoint of the adjacent inverter unit based on the second circuit control parameters to generate the second suppression result of the adjacent inverter unit. The second suppression result is analyzed to determine the second suppression notification information, which includes at least the current setpoint after suppression in this unit and the set of suppression action parameters that actually take effect this time, for reference alignment and action inheritance of downstream units; The illumination change notification information is analyzed to obtain the illumination change direction parameters, event start time parameters, and notification source identifier; Generate forwarding time parameters based on the timing of chain notifications sent by adjacent inverter units; The local identifier of the adjacent inverter unit is determined as the forwarding source identifier; The illumination change direction parameter, event start time parameter, notification source identifier, forwarding source identifier, forwarding transmission time parameter, and second suppression notification information are encapsulated; among them, the forwarding transmission time parameter refers to the timestamp of the actual frame output of the chained forwarding message of this unit; the forwarding source identifier refers to the unique identifier of this unit in the topology, which is used to form a traceable propagation trajectory chain; Based on the communication connection relationship and topology distribution of multiple inverter units, one or more adjacent inverter units that are topologically adjacent to the adjacent inverter units and have a communication connection relationship are identified. The chain forwarding notification message is sent to one or more adjacent inverter units so that the adjacent inverter units can generate the corresponding circuit control parameters, update and forward the chain forwarding notification message to the next inverter unit, until all inverter units have completed the suppression of the current setpoint.

[0043] Among them, the updates of propagation parameters, estimated arrival time, and second circuit control parameters are preferably completed by the next adjacent inverter unit on the receiving side: after receiving, the next adjacent inverter unit estimates the local link delay based on the forwarding transmission time and its local reception time, and performs self-update by combining the propagation path and propagation model, thereby reducing the spread of deviation along the link.

[0044] It is worth noting that in this embodiment, after receiving the notification linkage message, the adjacent inverter unit first determines the circuit control start time parameter based on the expected arrival time parameter and the start advance parameter, and generates the second circuit control parameter in advance to enter the pre-control preparation state. To avoid information inconsistencies caused by "upstream generating but not executed pre-control settings and then propagating them downstream" during chain-linked operations, this embodiment limits the triggering time of chain forwarding to: forwarding is only performed after the adjacent inverter unit reaches the circuit control start-up parameters, completes the second suppression process, and obtains the second suppression result. The purpose is twofold: First, the second circuit control parameters may still be subject to local operating state parameters (such as grid margin, bandwidth capacity, threshold boundary table, etc.) during the generation stage and undergo detailed correction. Furthermore, during the execution stage, differences in action branches and parameter adoption may occur due to over-limit trend judgment, anti-saturation risk judgment, etc. Therefore, propagating only "generated but not executed" pre-control information can easily lead to downstream units misjudging the actual suppression behavior of the upstream. Second, the linkage suppression in the cloud shadow propagation scenario needs to form a consistent "reference alignment" among multiple units. That is, the downstream unit should deduce its own reference current control target and reference current control parameters based on the actual suppression target and suppression action adopted by the upstream unit, thereby making the linkage link executable and traceable. Therefore, after performing the second suppression process, the adjacent inverter unit parses the second suppression result to obtain the current setpoint after suppression and the actual suppression action parameters used in this unit, and determines them as the second suppression notification information; then, the second suppression notification information is associated and encapsulated with the light change direction parameter, the event start time parameter, the notification source identifier, the forwarding source identifier and the forwarding transmission time parameter to generate a chain forwarding notification message and send it to the next adjacent inverter unit; Through the above mechanism, the chain information obtained by subsequent units is no longer the "predicted / preset" control intention, but the "implemented / executed" suppression results and action set. This enables subsequent units to perform circuit control target and control parameter alignment, scaling and limiting processing based on the real reference, reducing problems such as insufficient suppression, excessive load reduction or frequent control switching caused by reference deviation.

[0045] Specifically, in this embodiment, by establishing chain forwarding on the second suppression result, the chain forwarding notification message received by the downstream unit can simultaneously reflect the actual suppression target and actual suppression action of the upstream unit under local constraints, threshold boundaries, and execution branch effects. This transforms the linkage suppression of multiple inverter units from "parameter assumption linkage" to "result alignment linkage," reducing semantic drift and coordination mismatch caused by unit differences in the link. At the same time, the chain forwarding carries the notification source identifier and forwarding source identifier hop by hop, forming a traceable event propagation trajectory chain. This enables subsequent units to have more stable topological constraints and link basis when determining propagation paths, correcting delays, predicting arrival times, and correcting start times, reducing the pre-suppression window drift caused by communication delay differences and propagation speed fluctuations. Furthermore, since the chain message carries "executed results," it can avoid the downstream from prematurely or excessively following the suppression based on preset parameters that have not yet been executed or may be corrected by local limiting / slope limits. This ensures that controllable overcurrent risk is taken into account while balancing control smoothness and power generation efficiency, reducing the risk of frequent control switching, overall operational fluctuations, and grid-connected power quality degradation in cascaded scenarios.

[0046] In one embodiment, the method further includes: Obtain the circuit operating status parameters of adjacent inverter units and / or the photovoltaic operating parameters of photovoltaic units connected to them; Based on preset arrival confirmation criteria, the circuit operating status parameters and / or photovoltaic operating parameters are detected to determine the actual arrival time parameters of the sudden change in illumination to the adjacent inverter unit. Among them, the arrival confirmation criteria are used to confirm that "the cloud shadow has actually reached this unit". It is preferred to use multiple conditions in combination to improve reliability: for example, within the preset confirmation window, the DC side power or current shows a continuous decrease and the rate of decrease exceeds the threshold. At the same time, the grid-connected current feedback or the operating status related indication information shows a sudden change consistent with the decrease in illumination. The confirmation window can be set from 100 milliseconds to 1 second. The threshold can be obtained by calibrating the upper limit of steady-state noise and the typical cloud shadow change amplitude, for example, by setting it according to a certain proportion of rated power or rated current. The arrival time parameter is generated by comparing the actual arrival time parameter with the expected arrival time parameter. Specifically, the arrival time deviation parameter can be obtained by comparing the actual arrival time with the expected arrival time to determine whether the prediction is too early or too late and the magnitude of the deviation, which can be used for subsequent model correction. Based on the arrival time deviation parameter, propagation path parameter, and propagation model parameter, update the propagation parameters of the illumination change event. The propagation parameters include at least the average propagation speed parameter and / or the average single-hop propagation delay parameter. Specifically, the propagation parameters can be updated in the following way: based on the time consumed from the event origin to the actual arrival of this unit and the propagation path distance or number of hops, the propagation speed or single-hop delay corresponding to this event is re-estimated; then the estimation is smoothly integrated with the historical propagation model, for example, by adopting a sliding update method in which "the new estimation has a smaller weight and the historical model has a larger weight" to balance convergence speed and stability. The actual arrival time parameters, arrival time deviation parameters, and updated propagation parameters are encapsulated to generate deviation calibration notification information. Based on the communication connection relationship and topology distribution of multiple inverter units, one or more adjacent inverter units that are topologically adjacent to the adjacent inverter units and have a communication connection relationship are identified. The deviation calibration notification information is sent to one or more adjacent inverter units so that the adjacent inverter units can correct their expected arrival time parameters and / or circuit control start-up time parameters based on the deviation calibration notification information, and update their circuit control parameters.

[0047] Specifically, in this embodiment, since the second suppression is a pre-suppression based on the expected arrival time, its start time inevitably deviates from the actual arrival time of cloud shadow shading. To prevent this deviation from accumulating in the chain propagation and causing the start window of subsequent units to continuously drift, the adjacent inverter unit further confirms the actual arrival of the sudden change in illumination through local parameter detection after performing the second suppression, obtains the actual arrival time and calculates the arrival deviation, and then updates and estimates the propagation parameters by combining the propagation path and historical propagation model. Finally, it feeds back to the subsequent units in the form of deviation calibration notification. Through the above mechanism, the subsequent units can re-correct the expected arrival time and start time based on the calibration information of "actual arrival - deviation amount - updated model", thereby reducing the propagation risk of pre-suppression error, improving the timing consistency and suppression accuracy under multi-hop cascade linkage, and reducing the problems of excessive load reduction, control jitter and grid power quality degradation caused by premature / late suppression.

[0048] In one embodiment, the method further includes: Adjacent inverter units receive illumination change notification information, chain forwarding notification messages, and / or deviation calibration notification information from at least two different notification source identifiers and / or different forwarding source identifiers; Each notification message is analyzed to obtain the corresponding parameters for the direction of the sudden change in illumination, the start time of the event, the notification sending time, and / or the forwarding sending time, and information receiving time parameters are generated accordingly. Based on the information reception time parameter, the notification transmission time parameter and / or the forwarding transmission time parameter, link transmission delay parameters are generated respectively, and the event start time parameter is delayed to obtain the local equivalent time parameters of the start of multiple events. Based on the notification source identifier / forwarding source identifier, as well as the communication connection relationship and topology distribution, the corresponding propagation path parameters are determined respectively, and multiple candidate values ​​of the expected arrival time are generated by combining the propagation model parameters. Multiple candidate values ​​for estimated arrival time are fused to generate a fused estimated arrival time parameter; wherein, the fusion calculation includes at least one or more of the following processes: weighting by path level parameter, weighting by link transmission delay parameter, weighting by notification type weight, and removing candidate values ​​that exceed a preset outlier threshold; The start-up advance parameter and / or circuit-controlled start-up timing parameter are adjusted based on the fused expected arrival time parameter, and the second circuit control parameter is updated. The correction can be achieved by "direct replacement" of the fusion result or by "gradual correction": the original prediction and the fusion prediction are mixed in a preset ratio to make the correction process smoother; the mixing ratio can be adjusted according to the consistency of the candidates, and the higher the consistency, the greater the proportion of the fusion result.

[0049] Preferably, the fusion calculation can be obtained by assigning weights to each candidate value and performing weighted fusion. The weights can be related to the path level, link delay stability, and notification type reliability. Preferably, the notification type weights satisfy the condition that "deviation calibration notifications are higher than chain suppression result notifications, and higher than single pre-notifications".

[0050] Outlier removal can be achieved by first calculating the central trend (such as the median level) of candidate values, and then removing candidate values ​​that deviate from the central trend by more than a preset threshold, in order to avoid abnormal links or abnormal messages from skewing the fusion results; the preset threshold can be set by the historical latency fluctuation range or the allowable prediction error range.

[0051] Specifically, in this embodiment, to address the instability of single-source prediction caused by fluctuations in cloud propagation speed, inconsistent local occlusion patterns, or deviations in individual reports, adjacent inverter units perform multi-source fusion processing on report information from different sources / different hops, involving "time synchronization—candidate prediction—fusion correction": First, a unified local equivalent time corresponding to each source is generated, and multiple sets of expected arrival time candidate values ​​are obtained. Then, a more robust fused expected arrival time is formed through weighted fusion and outlier elimination, so that the determination of the start time does not depend on a single message, but rather on the comprehensive topology path constraints and link delay consistency to obtain a more reliable time prediction. Through the above mechanism, the risk of error amplification can be significantly reduced in scenarios with multi-hop propagation and multiple links, the reliability of arrival time prediction and pre-suppression start window can be improved, and the overall operational fluctuations caused by frequent control switching and coordination mismatch can be reduced.

[0052] In one embodiment, the method further includes: The adjacent inverter unit analyzes the first suppression result received and / or the second suppression result of the upstream adjacent inverter unit to obtain the current setpoint after suppression by the upstream unit and the corresponding suppression action parameters, and generates the reference current control target amount and reference current control parameters accordingly. The current setpoint of the adjacent inverter unit is obtained and compared with the reference current control target to generate the target current bias parameter. The target current bias parameter refers to the difference between the current setpoint target of this unit and the reference target, and is used to reflect "how much adjustment is needed" and "the direction of adjustment". Based on the target quantity bias parameters and the circuit operating status parameters of adjacent inverter units, determine the upper limit parameters of the target change amplitude and / or the upper limit parameters of the target change rate. The upper limit parameters can be determined in the following ways: the upper limit of the amplitude is determined based on the size of the grid-connected current margin; the smaller the margin, the smaller the allowable single adjustment amplitude. The upper limit of the rate of change is determined based on the current loop bandwidth or control response capability; the lower the bandwidth, the smaller the allowable rate of change. At the same time, the upper limit parameters can also be constrained by the grid-connected current limit and the factory calibration boundary of the equipment to ensure that they do not exceed the allowable range of the hardware and grid-connected specifications. Preferably, the upper limit parameters can be obtained by looking up a table: the corresponding upper limit is read from the pre-stored boundary table according to the "margin classification" and "bandwidth classification". The target quantity of the reference current regulation is subjected to target limiting processing to limit it within the range defined by the upper limit parameter of the target change range, thus obtaining the limited reference target quantity; The target amplitude limiting process can be implemented in the following way: the reference target is restricted to an allowable range centered on the current target with the upper limit of amplitude as the radius, and the part exceeding the range is truncated; The target slope limiting processing is performed on the target quantity of the reference current regulation or the target quantity of the limit reference to limit its rate of change within the range of the rate of change limited by the upper limit parameter of the target rate of change, so as to obtain the slope-limited reference target quantity. The target slope limit processing can be obtained in the following way: within each control cycle, the target change is limited to the "allowable increment corresponding to the upper limit of the change rate", so that the target gradually approaches the reference target at a speed not exceeding the allowable speed; The slope-limited reference target quantity is determined as the second current regulation target quantity, and the upper limit parameter of the target change amplitude and / or the upper limit parameter of the target change rate are encapsulated as part of the second circuit regulation parameters.

[0053] Specifically, in this embodiment, the suppression result inheritance is used to achieve "reference alignment" in the linkage of multiple inverter units, enabling downstream units to use the actual suppression target and action of the unit that has already occurred as a reference for pre-suppression. However, considering the differences in grid connection margin, control bandwidth, grid connection limit, etc. among different inverter units, directly copying the upstream suppression target value may easily lead to excessive load reduction or target oscillation. Therefore, this embodiment introduces target bias calculation and local amplitude / slope constraint before the reference target is implemented, ensuring that the adjustment range and adjustment speed of the reference target are consistent with the local capability. The constraint result and constraint parameters are also incorporated into the second circuit control parameters, thereby ensuring that control smoothness and power generation efficiency are taken into account while ensuring that the overcurrent risk is controllable, reducing the risk of insufficient suppression, excessive suppression, and unstable operation caused by parameter mismatch in the cascade linkage scenario.

[0054] For example, to further illustrate this embodiment, such as Figure 3The photovoltaic array shown is obscured by cloud shadows. U11 to U33 in the diagram all refer to photovoltaic arrays, and each array is connected to a corresponding inverter unit. Communication connections are established between the inverter units, enabling the transmission and chaining of notification information between adjacent inverter units. In a scenario where the cloud shadow only sequentially obscures U11, U21, U22, and U32 along its direction of travel (the remaining arrays are not obscured or only slightly obscured), the notification and pre-regulation process in this embodiment can be briefly described as follows: When the cloud shadow first blocks U11, U11 detects a sudden change in illumination (the direction of the change is downward), triggers local suppression and generates the first suppression result, and then sends illumination change notification information to the adjacent inverter unit with which it has a communication connection (for example, it sends it to U21, and can also send it to U12 at the same time). The notification information carries at least the event start time parameter, the change direction parameter, and the notification source identifier (U11) and other fields. After receiving the notification, U21 records the information reception time, generates the link transmission delay by combining the event start time, and determines the propagation path parameters based on the topology. Then, it estimates the expected arrival time of the light change to U21 and determines the circuit control start time, so that U21 completes the generation of the second circuit control parameters and enters the pre-control preparation state before the expected arrival time. When the start time arrives, the second suppression is performed to suppress possible overcurrent risks in advance. The cloud shadow continues to advance and block U21. After U21 reaches its circuit control start time and completes the second suppression, it encapsulates the second suppression result (such as the current setpoint after suppression and the corresponding suppression action parameters) with fields such as the notification source identifier, the forwarding source identifier (U21) and the forwarding transmission time parameters, generates a chain forwarding notification message and sends it to U22 and U31. After receiving the U22 signal, the link transmission delay is obtained based on the receiving time and the forwarding time. The expected arrival time is estimated by combining the propagation path parameters to determine the circuit control start time, so as to enter the pre-control in advance and perform the second suppression at the start time. When the cloud shadow further obscures U22, U22 completes the second suppression and obtains the second suppression result, and then sends a chain forwarding notification message containing its actual suppression result and action parameters to U32 and U23; After receiving the signal, U32 estimates the expected arrival time and determines the circuit control start time using the same mechanism, thus achieving pre-control of its own occlusion. This ensures that the second suppression is completed when the cloud shadow finally occludes U32, thereby suppressing the current surge caused by occlusion within a controllable range. U32 then sends a notification message and the corresponding suppression result to U31 and U33. In this process, for units that receive the notification but are not actually shaded during the chain notification propagation, such as U12, U31, and U33, although they receive the notification and calculate the expected arrival time, generate the second circuit control parameters, and enter the pre-control preparation state, if the circuit operation parameters and / or photovoltaic operation parameters of this unit do not enter transient evolution or show a sudden change characteristic consistent with shading during the expected circuit control start time and extended waiting period, it is determined that the expected arrival is not valid or the shading intensity is insufficient. The unit then cancels the generated second circuit control parameters and exits the pre-control state (or smoothly restores the current setpoint to the original control target according to the preset backoff strategy) to avoid excessive load reduction and grid power fluctuation caused by ineffective linkage, and improve the accuracy and economy of chain pre-control in local shading scenarios. Similarly, when the cloud shadow leaves U11, U21, U22 and U32 in sequence, the message communication and pre-control process between the corresponding inverter units is similar to the above process, except that the direction of the sudden change in illumination changes from decreasing to increasing, which will not be described in detail here.

[0055] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method.

[0056] In one embodiment, such as Figure 4 As shown, this application also provides an overcurrent suppression system for a photovoltaic grid-connected inverter, applied to multiple interconnected inverter units. The system includes: The operation status indication module is used to obtain the circuit operation status parameters corresponding to the inverter unit and extract the operation status related indication information. It matches the operation status related indication information with the pre-stored transient event characteristics to generate transient matching results. The first circuit control module is used to respond to the transient matching result being characterized as a sudden change in illumination, and then, based on the circuit operating state parameters and the matched sudden change in illumination transient characteristics, generate first circuit control parameters to at least suppress the current setpoint of the inverter unit and generate a first suppression result. The event notification module is used to generate light change notification information based on the light change transient, and send the light change notification information and the first suppression result to the adjacent inverter unit; The second circuit control module is used to respond to the light change notification information and the first suppression result received by the adjacent inverter unit, and then generate the second circuit control parameters based on the light change notification information, the first suppression result and the circuit operation state parameters of the adjacent inverter unit to at least suppress the current setpoint of the adjacent inverter unit.

[0057] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, generator software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0058] The above provides a detailed description of the overcurrent suppression method and system for a photovoltaic grid-connected inverter provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only intended to help understand the method and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. A method for suppressing overcurrent in a photovoltaic grid-connected inverter, characterized in that, The method, applied to multiple interconnected inverter units, includes: The inverter unit acquires the corresponding circuit operating status parameters and extracts the operating status association indication information. It then matches the operating status association indication information with the pre-stored transient event features to generate a transient matching result. In response to the transient matching result being characterized as a sudden change in illumination transient, the inverter unit generates a first circuit control parameter based on the circuit operating state parameters and the matched sudden change in illumination transient characteristics to at least suppress the current setpoint of the inverter unit and generate a first suppression result. The inverter unit generates illumination mutation notification information based on the illumination mutation transient, and sends the illumination mutation notification information and the first suppression result to the adjacent inverter unit; In response to the adjacent inverter unit receiving the light change notification information and the first suppression result, the adjacent inverter unit generates a second circuit control parameter based on the light change notification information, the first suppression result, and the circuit operating state parameters of the adjacent inverter unit to at least suppress the current setpoint of the adjacent inverter unit.

2. The overcurrent suppression method for photovoltaic grid-connected inverters according to claim 1, characterized in that, The inverter unit acquires the corresponding circuit operating status parameters and extracts the operating status associated indication information, including: Obtain the circuit operating status parameters of the inverter unit; Based on preset transient correlation indicators, the circuit operating state parameters are mapped to indicators to generate multiple transient correlation feature components. Based on one or more of the aforementioned transient operational associated feature components, a combined mapping is performed to generate a transient operational associated vector, which is then determined as the operational status associated indication information.

3. The overcurrent suppression method for photovoltaic grid-connected inverters according to claim 2, characterized in that, The step of matching the operational status association indication information with pre-stored transient event features to generate transient matching results includes: Based on the preset transient evolution discrimination conditions and the operation state association indication information, the corresponding inverter unit is determined to perform transient evolution trend judgment and obtain transient trend discrimination result; In response to the transient trend discrimination result indicating that the inverter unit has a transient evolution trend, the operating state association indication information is parsed to obtain the operating transient association vector of the inverter unit; A transient matching feature vector is generated based on the pre-stored transient event features, wherein the transient event features include at least one or more of the following: transient features of sudden changes in illumination and transient features of power grid disturbances; Based on a preset matching criterion, the feature matching degree between the transient correlation vector and multiple transient matching feature vectors is determined, and the transient event feature corresponding to the highest feature matching degree is determined as the highest matching transient event feature. Based on the highest feature matching degree, the proportion of effective feature components of the transient correlation vector, and / or the difference between the highest feature matching degree and the second highest feature matching degree, the matching confidence of the highest matching transient event feature is determined. In response to the feature matching degree of the highest matching transient event feature being greater than or equal to the feature matching threshold, and the matching confidence degree being greater than or equal to the confidence threshold, a transient matching result representing the transient event type corresponding to the highest matching transient event feature is generated; In response to the highest matching transient event feature having a feature matching degree less than a feature matching threshold, or the matching confidence degree being less than a confidence threshold, a transient matching result representing that the transient event is not matched is generated.

4. The overcurrent suppression method for photovoltaic grid-connected inverters according to claim 1, characterized in that, Before matching the operation status association indication information with pre-stored transient event features, the method further includes: The historical circuit operation status parameters of multiple inverter units, the historical photovoltaic operation parameters of multiple photovoltaic units connected to the inverter units, and historical scene data are obtained. The historical scene data includes at least historical weather event information and historical power grid event information. The historical circuit operation status parameters and the historical photovoltaic operation parameters are segmented based on a preset time window to obtain multiple sets of operation parameters for historical segments; Based on preset transient correlation indicators, the operation parameter sets of multiple historical segments are processed to generate multiple operation indicator sets of the historical segments; In response to the set of operating indicators satisfying the preset transient evolution discrimination condition, the corresponding historical segment is determined as a transient segment, and the corresponding set of operating parameters is determined as a transient parameter set; Based on the time periods corresponding to multiple transient segments, event types with preset time correlations to the transient segments are sequentially filtered from the historical weather event information and historical power grid event information to obtain a scene-related event set; The scene-related event set is classified and aggregated based on event type to obtain multiple scene-related event subsets; Based on the multiple transient parameter sets corresponding to the subset of events associated with the scene, an event transient sample set is generated, and the intrinsic similarity of the event transient sample set is determined. If the intrinsic similarity of the event transient sample set is greater than or equal to a preset similarity threshold, the corresponding event type is determined to be a transient associated event type, and statistical features are extracted from the event transient sample set to obtain event transient sample features. Transient event features are generated based on the transient associated event type and the transient sample features of the event, and then distributed to multiple inverter units to generate transient matching results.

5. The overcurrent suppression method for photovoltaic grid-connected inverters according to claim 1, characterized in that, The inverter unit generates first circuit control parameters based on the circuit operating state parameters and the matched transient characteristics of sudden changes in illumination, including: Based on the aforementioned transient characteristics of illumination change, the corresponding transient sample characteristics of illumination change are determined; Align the circuit operating state parameters with the transient sample features of the sudden change in illumination to determine the current transient stage parameters of the inverter unit; Based on the current transient stage parameters and the characteristics of the light sudden transient sample, the subsequent operating state of the inverter unit in the preset prediction time domain is predicted, and the predicted operating state parameters are generated. Based on the predicted operating state parameters, multiple circuit risk items and corresponding circuit risk indicators are determined, and based on the multiple circuit risk items and corresponding circuit risk indicators, multiple control items of the inverter unit are determined. Based on preset coordination rules, multiple control items are coordinated and integrated to generate the first circuit control parameters.

6. The overcurrent suppression method for photovoltaic grid-connected inverters according to claim 1, characterized in that, The process of suppressing the current setpoint of the inverter unit and generating a first suppression result includes: Analyze the circuit operating state parameters of the inverter unit to determine at least the current setpoint, current limiting related quantity, and control saturation related quantity of the inverter unit. Based on the matched transient characteristics of the illumination change, determine the direction parameters of the illumination change. The first circuit control parameters are analyzed to generate a current control parameter set to control the current setpoint of the inverter unit. The current control parameter set includes at least one or more of the following: slope limit parameter, amplitude limit threshold, over-limit judgment threshold, enhancement suppression parameter, anti-saturation parameter in the downward direction, current limit parameter, and recovery slope limit parameter. In response to the illumination change direction parameter representing the increase in illumination intensity, the rising slope index of the current setpoint is constrained according to the slope limiting parameter, and the amplitude index of the current setpoint is constrained according to the amplitude limiting threshold, thereby generating the current setpoint after initial suppression. Based on the initial suppressed current setpoint and combined with the circuit operating state parameters, the predicted quantity of the inverter unit is determined. The predicted quantity includes at least one or more of the following: predicted peak output current and predicted current change rate. The predicted quantity is compared with the over-limit judgment threshold to obtain the over-limit judgment result. If the over-limit judgment result indicates an over-limit, then the enhanced suppression processing is applied to the initially suppressed current setpoint according to the enhanced suppression parameter to obtain the suppressed current setpoint. In response to the light intensity decrease characterized by the light change direction parameter, a control saturation risk judgment result is generated based on the control saturation correlation quantity and the anti-saturation parameter, and a synthetic current over-limit risk judgment result is generated based on the current limiting correlation quantity and the current limit parameter. If the control saturation risk determination result indicates that the inverter unit has a control saturation risk, then according to the anti-saturation parameter and / or the recovery slope limit parameter, the current setpoint is subjected to a process to suppress the control saturation release shock. The process includes at least one of the following: performing anti-saturation processing on the current setpoint and applying a recovery slope limit to the rate of change index of the current setpoint to suppress the sudden change in the current setpoint caused by the control loop saturation release. If the result of the synthetic current over-limit risk assessment indicates that the inverter unit has a synthetic current over-limit risk, then the current setpoint is subjected to a limiting process according to the current limit parameter. The limiting process includes at least one of the following: limiting the synthetic current vector amplitude index and limiting the component current setpoint to obtain a suppressed current setpoint. One or more current control parameters used in the set of current control parameters are determined as suppression action parameters, and the first suppression result of the inverter unit is generated based on the suppression action parameters and the current setpoint after suppression.

7. The overcurrent suppression method for photovoltaic grid-connected inverters according to claim 1, characterized in that, The inverter unit generates illumination mutation notification information based on the illumination mutation transient, and sends the illumination mutation notification information and the first suppression result to the adjacent inverter unit, including: Based on the light change transient, at least the light change direction parameter and the event start time parameter of the corresponding light change event are determined. The identifier corresponding to the inverter unit is determined as the notification source identifier; The illumination change direction parameter, the event start time parameter, and the notification source identifier are encapsulated to generate the illumination change notification information. Analyze the first suppression result to determine the first suppression notification information, which includes at least the current setpoint of the inverter unit after suppression and the corresponding suppression action parameters. The illumination change notification information and the first suppression notification information are optically encapsulated to generate a notification linkage message; Based on the communication connection relationship and topology distribution of the multiple inverter units, one or more adjacent inverter units that are topologically adjacent to the inverter unit and have a communication connection relationship are identified. The notification and linkage message is sent to one or more of the adjacent inverter units.

8. The overcurrent suppression method for a photovoltaic grid-connected inverter according to claim 7, characterized in that, The adjacent inverter unit generates second circuit control parameters based on the illumination change notification information, the first suppression result, and the circuit operating state parameters of the adjacent inverter unit, including: The illumination change notification information is parsed to obtain the illumination change direction parameter, the event start time parameter, and the notification source identifier of the illumination change event, and the notification sending time parameter carried in the illumination change notification information is obtained. Based on the time when the adjacent inverter unit receives the light change notification information, an information reception time parameter is generated; Based on the information reception time parameter and the notification transmission time parameter, the link transmission delay parameter between the adjacent inverter unit and the inverter unit is generated; Based on the notification source identifier and the communication connection relationship and topology distribution of the multiple inverter units, the propagation path parameters of the illumination change event from the notification source inverter unit to the adjacent inverter unit are determined. The propagation path parameters include at least: path distance parameters and path order parameters. An event notification interval parameter is generated based on the notification sending time parameter and the event start time parameter, and the event notification interval parameter is adjusted for delay based on the information receiving time parameter and the link transmission delay parameter to obtain the local equivalent time parameter of the event start. Based on the propagation model parameters obtained from the statistics of historical illumination change events and the propagation path parameters, the propagation time parameters are determined, and based on the local equivalent time parameter of the event start and the propagation time parameters, the expected arrival time parameter of the illumination change event is determined, wherein the propagation model parameters are average propagation speed parameters or average single-hop propagation delay parameters. The start-up advance parameter is determined based on the expected arrival time parameter and the current loop response time parameter of the adjacent inverter unit, and the circuit control start-up time parameter is determined based on the start-up advance parameter. Analyze the first suppression result to obtain the current setpoint of the notification source inverter unit after suppression and the corresponding suppression action parameters; The reference current control target amount of the adjacent inverter unit is determined based on the suppressed current setpoint, and the reference current control parameter of the adjacent inverter unit is determined based on the suppression action parameter and the circuit operation state parameter of the adjacent inverter unit. The second circuit control parameters of the adjacent inverter unit are generated based on the circuit control start-up time parameters, the reference current control target amount, the reference current control parameters, and the circuit operation status parameters of the adjacent inverter unit.

9. The overcurrent suppression method for a photovoltaic grid-connected inverter according to claim 8, characterized in that, The step of generating the second circuit control parameters of the adjacent inverter unit based on the circuit control start-up time, the reference current control target amount, the reference current control parameters, and the circuit operating state parameters of the adjacent inverter unit includes: Analyze the circuit operating status parameters of the adjacent inverter units to determine the grid connection point voltage parameters, DC bus voltage parameters, grid connection current feedback effective value parameters, grid connection current limit parameters, current loop bandwidth parameters, and grid connection side equivalent impedance estimation parameters of the adjacent inverter units. A grid-connected current margin parameter is generated based on the grid-connected current feedback effective value parameter and the grid-connected current limit parameter. A target correction coefficient is determined by the grid-connected current margin parameter according to a preset target mapping relationship, and the target correction coefficient is limited to a preset coefficient range. Based on the target correction coefficient, a scaling operation is performed on the reference current control target amount to obtain the refined current control target amount; The slope correction coefficient is determined based on the current loop bandwidth parameter by using a preset slope mapping relationship; The reference current control parameters are analyzed to obtain the current slope limit parameters and the recovery slope parameters. Based on the slope correction coefficient, a scaling operation is performed on the current slope limit parameters and the recovery slope parameters to obtain the slope refinement parameters. The threshold correction coefficient is determined based on the grid-connected side equivalent impedance estimation parameters by using a preset threshold mapping relationship. The amplitude limiting threshold parameter and the over-limit judgment threshold parameter are obtained by analyzing the reference current control parameter, and a scaling operation is performed on the amplitude limiting threshold parameter and the over-limit judgment threshold parameter based on the threshold correction coefficient to obtain the threshold refinement parameter; The target current regulation target quantity is subjected to target limiting processing to limit the target current regulation target quantity within the target range determined by the grid-connected current limit parameter, thereby obtaining the second current regulation target quantity; Slope limiting processing is performed on the slope refinement parameter to limit the current slope limiting parameter and the recovery slope parameter within the slope range determined by the pre-stored slope boundary table, thereby obtaining the second current slope control parameter; The threshold refinement parameter is subjected to threshold limiting processing to restrict the amplitude limiting threshold parameter and the over-limit judgment threshold parameter to a threshold range consistent with the grid-connected current limit parameter, thereby obtaining the second current amplitude threshold control parameter; The circuit control start-up time parameter, the second current control target amount, the second current slope control parameter, and the second current amplitude threshold control parameter are combined as the second circuit control parameter of the adjacent inverter unit.

10. An overcurrent suppression system for a photovoltaic grid-connected inverter, characterized in that, The system is applied to multiple interconnected inverter units and includes: The operation status indication module is used to obtain the circuit operation status parameters corresponding to the inverter unit and extract the operation status related indication information, and match the operation status related indication information with the pre-stored transient event features to generate a transient matching result. The first circuit control module is used to respond to the transient matching result being characterized as a sudden change in illumination transient, and then, based on the circuit operating state parameters and the matched sudden change in illumination transient characteristics, generate first circuit control parameters to at least suppress the current setpoint of the inverter unit and generate a first suppression result. The event notification module is used to generate light change notification information based on the light change transient, and send the light change notification information and the first suppression result to the adjacent inverter unit; The second circuit control module is used to respond to the adjacent inverter unit receiving the light change notification information and the first suppression result, and then generate a second circuit control parameter based on the light change notification information, the first suppression result and the circuit operating state parameters of the adjacent inverter unit to at least suppress the current setpoint of the adjacent inverter unit.

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