Intelligent controller capable of automatically isolating photovoltaic external faults

Abstract

The invention discloses an intelligent controller for self-isolating photovoltaic external faults, which relates to the technical field of power electronic control and comprises a time anchoring module, a rhythm correction module, an isolation planning module, an energy balance module, a track traction module and a reset regulation and control module. Tracking the propagation sequence of the external disturbance on the side of the plurality of photovoltaic modules, generating a rhythm list, and marking a disturbance arrival window. Unification of the isolation time sequence of the photovoltaic module is realized through the time anchoring chain and the correction rhythm, voltage fluctuation caused by asynchronous response is eliminated, and continuous and stable bus voltage is guaranteed; through cooperative regulation and control of an isolation rhythm frame, a balance index and a phase traction dome, energy flow direction balance and segmented resetting are realized, stable convergence of inverter control is ensured, and the operation safety and reliability of a system are improved.

Description

Technical Field

[0001] This invention relates to the field of power electronic control technology, and more specifically to an intelligent controller for self-isolation of external photovoltaic faults. Background Technology

[0002] A self-isolating photovoltaic (PV) external fault intelligent controller refers to an intelligent power electronic control device deployed in PV modules or DC-side circuits. It continuously collects and analyzes the operating status of the modules, such as voltage, current, power, and temperature, and combines this with locally preset control strategies or remote control commands from a cloud platform to determine the external operating environment of the PV system. When it detects grid-side anomalies, string-side anomalies, maintenance safety triggering conditions, or other external fault risks, it can automatically drive the internal power switching unit to quickly shut down the corresponding PV module or circuit without manual intervention, reducing the output voltage to a safe range, thereby achieving active isolation of the fault source from the rest of the system. Simultaneously, the controller maintains communication with the gateway and cloud platform via wireless communication, reporting status information and receiving strategy updates while performing isolation control. It also supports remote reset or linkage control, enabling the PV system to autonomously identify, make autonomous decisions, and autonomously isolate itself under external fault conditions, improving overall operational safety and controllability.

[0003] The existing technology has the following shortcomings:

[0004] In existing technologies, photovoltaic systems typically employ a combination of independent sampling at the module level and local decision-making to achieve isolation control under external faults. Each photovoltaic module's intelligent controller periodically collects state parameters such as voltage and current during operation and independently triggers isolation actions based on its own decision-making results. However, under dynamic conditions where external grid disturbances propagate rapidly along the DC side, inherent differences in sampling period settings, signal processing paths, and timing responses among different modules can easily lead to time skew in the identification of the same disturbance event, causing inconsistencies in the isolation triggering actions of each module on the timeline. This inconsistent isolation behavior causes the DC-side circuit to be in an alternating state of partial module shutdown and continuous output for a very short period, resulting in repeated instantaneous voltage drops and rapid recoveries on the DC bus, forming high-frequency voltage fluctuations. Under the aforementioned conditions of severe voltage fluctuations, the voltage control loop and current control loop inside the inverter are difficult to maintain a stable working state, which can easily lead to control loop oscillations. In some cases, the inverter's protection logic may misjudge the situation as an abnormal condition and trigger protection actions, resulting in unplanned inverter shutdowns or protection failures. This causes the impact of external grid disturbances to extend from the local component level to the inverter level, reducing the overall stability and safety of the photovoltaic system.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide an intelligent controller for self-isolating external photovoltaic faults, in order to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an intelligent controller for self-isolating external photovoltaic faults, comprising a time anchoring module, a rhythm correction module, an isolation planning module, an energy balance module, a trajectory traction module, and a regression control module:

[0008] The time anchoring module constructs a unified time anchoring chain, tracks the propagation sequence of external disturbances on multiple photovoltaic modules, generates a rhythm list, and marks the arrival window of the disturbance;

[0009] The rhythm correction module performs alignment analysis on the sampling rhythm of each photovoltaic module based on the arrival window of external disturbances marked in the rhythm list, extracts the sampling phase deviation, forms a phase correction factor, and uses the phase correction factor to correct the rhythm list to generate a corrected rhythm.

[0010] The isolation planning module rearranges the isolation response sequence of photovoltaic modules according to the correction rhythm, constructs a hierarchical isolation trigger sequence, generates isolation rhythm frames, and limits the timing boundaries of isolation actions.

[0011] The energy balance module redistributes the transient energy flow direction on the DC side according to the timing boundary of the isolation rhythm frame, and constructs a slow-release ridge at the bus level to form a corresponding balance index.

[0012] The trajectory traction module tractions and shapes the inverter's reference operating trajectory based on the balance index, generates a reference trajectory traction band synchronized with the isolation rhythm frame, enables voltage control and current control to converge gradually according to the correction rhythm, and forms a recovery threshold cable.

[0013] The reversion control module dynamically controls the phase traction dome based on the recovery threshold cable. It performs micro-opening and closing of the isolation channel according to the isolation rhythm frame time structure, guiding the photovoltaic modules to synchronously release isolation and revert in segments, so as to suppress control instability caused by DC side voltage collapse and recovery.

[0014] Preferably, the steps for generating a rhythm list and marking the arrival window of perturbations are as follows:

[0015] Continuous monitoring of grid-side input voltage, current frequency and power fluctuations; when external disturbances occur, the DC-side voltage change trend is used to identify the disturbance start time and determine the start point of the time anchor chain.

[0016] Establish a time recording benchmark on each photovoltaic module side to record the first fluctuation moment when the disturbance signal is transmitted to the module input end and form the initial time set of disturbance propagation;

[0017] Based on the geographical location, line length, conductor impedance and connection position of each photovoltaic module, the disturbance propagation path is mapped, the temporal sequence of disturbance propagation is arranged and a time axis structure is generated.

[0018] Based on the time axis structure, the arrival time of disturbances and the propagation interval are integrated to generate a rhythm list. The arrival time of disturbances for each photovoltaic module is then extended in the rhythm list to form a time interval with a start and an end point to form a disturbance arrival window.

[0019] Preferably, the steps for generating the corrected rhythm are as follows:

[0020] The sampling sequence of voltage change, current change and output power change values ​​of multiple photovoltaic modules is recorded within the external disturbance arrival window, and the sampling rhythm is determined by taking the start time of the external disturbance arrival window as the time zero point.

[0021] Taking the photovoltaic module that is first affected by the external disturbance as the reference object, the sampling time series of the remaining photovoltaic modules are compared with the sampling time series of the reference photovoltaic module one by one, and the sampling start time difference, sampling interval difference and sampling end time difference are calculated to form a time offset dataset.

[0022] The time offset data is converted into sampling phase deviation, arranged according to the propagation direction of external disturbance to form a phase sequence, and integrated into a phase correction factor.

[0023] The phase correction factor is used to correct the time nodes corresponding to the photovoltaic modules in the rhythm list to generate the corrected rhythm.

[0024] Preferably, the steps for generating isolated rhythm frames are as follows:

[0025] The identification, decision-making, driving, and execution processes of multiple photovoltaic modules during external disturbances are time-series processed to form a complete isolation response time trajectory and arrange a preliminary isolation response sequence.

[0026] Based on the physical distribution location of the photovoltaic modules in the DC circuit, the output power level, and the intensity of their influence on the bus voltage, the photovoltaic modules are divided into a first triggering layer near the positive end of the bus, a second triggering layer in the middle section, and a third triggering layer near the negative end of the bus.

[0027] Using the time anchor point of the corrected rhythm as a reference, the start and end times of each trigger layer are determined, isolated rhythm frames are generated, and a stepped structure is formed on the time axis;

[0028] The timing range of isolation actions and energy regulation is limited according to the time boundary of the isolation rhythm frame, and a continuous energy regulation window is formed between each trigger layer to maintain the stability of the bus voltage.

[0029] Preferably, the time boundary of the isolation rhythm frame and the energy control window are continuously connected on the time axis. The end time of each trigger layer is used as the start time of the next trigger layer. During the isolation action, the energy control window synchronously adjusts the output power of the photovoltaic module to keep the bus voltage change rate within a preset range, thereby achieving time coordination and balanced transition between the isolation action and energy control.

[0030] Preferably, the process for forming the balance index is as follows:

[0031] Within the time frame of the isolation rhythm, the voltage change rate, current change rate, and bus voltage response of multiple photovoltaic modules during the isolation process are identified to determine the direction and amount of transient energy transfer.

[0032] Based on the layered triggering order of the isolation rhythm frames, the energy flow direction is redistributed in a time-division manner, and the energy absorption ratio and release ratio are set in each layer time interval to maintain the continuity of energy transfer.

[0033] A buffer ridge is constructed at the DC bus level, and a dynamic energy buffer zone is formed by adjusting the bus capacitor bank, wiring inductance and shunt path.

[0034] Based on the energy absorption and release characteristics of the slow-release ridge, a balance index corresponding to the isolation rhythm frame is formed, and the bus voltage variation range is constrained by the balance index node to maintain dynamic energy balance.

[0035] Preferably, the steps for restoring the threshold cable formation are as follows:

[0036] Based on the established balance index, capture the operating status of the inverter voltage control loop and current control loop, record the bus voltage change rate, inverter input current amplitude and phase change trend, and determine the control deviation direction.

[0037] Based on the time distribution characteristics of the isolation rhythm frame, the inverter voltage reference curve and current reference curve are rearranged in time to make them consistent with the energy balance point corresponding to the balance index in time.

[0038] The shaped voltage and current reference curves are unfolded on the time axis to form voltage and current traction bands synchronized with the isolation rhythm frame.

[0039] The voltage control loop and current control loop of the inverter are subjected to traction synchronous constraints so that they gradually converge according to the correction rhythm and achieve synchronous adjustment in time.

[0040] At the end of the reference trajectory traction belt, a recovery threshold is formed based on the convergence state of the balance index and the termination boundary of the isolation rhythm frame. This threshold is used to determine the transition time window for the inverter from rhythm-guided control to normal operation.

[0041] Preferably, the formation of the recovery threshold cable is based on the bus voltage stabilization start time and the inverter output current phase stabilization time. The start and end intervals of the recovery threshold cable are determined by detecting the balance state of the bus energy over a continuous period of time. Within this interval, the inverter gradually adjusts its output according to the reference trajectory of the end of the traction belt, so that the voltage and current remain synchronous and stable, and automatically switch to normal grid-connected operation after the threshold cable is completed.

[0042] Preferably, based on the dynamic control of the phase traction dome initiated by the recovery threshold cable, the isolation channel is opened and closed slightly according to the time structure of the isolation rhythm frame, guiding the photovoltaic modules to synchronously release isolation and return in segments. The steps are as follows:

[0043] After the recovery threshold is determined, the phase traction dome time frame, which includes the rising segment, the balancing segment, and the convergence segment, is constructed along the positive direction of the time axis, taking the stable time point of the bus voltage and the inverter output current as the starting condition.

[0044] Based on the layered time structure of the isolation rhythm frame, a slight opening operation is performed on the isolation channel of each photovoltaic module, and the output voltage of the photovoltaic module is gradually made to converge with the bus voltage by adjusting the conduction angle of the power switch;

[0045] Phase synchronous traction is implemented under the guidance of the phase traction dome. By delaying or advancing the conduction time, the voltage recovery curve of each photovoltaic module is limited to the dome time envelope to achieve synchronous recovery.

[0046] During the middle period of the dome, the isolation channel is dynamically controlled in a breathing manner, and the energy cycle release and absorption balance is achieved through periodic micro-closing and opening;

[0047] Based on the convergence time structure of the phase traction dome, a segmented regression operation is performed to enable the photovoltaic modules to gradually resume conduction and smoothly return to steady-state operation in both time and energy dimensions.

[0048] The technical effects and advantages provided by the present invention in the above technical solution are as follows:

[0049] This invention achieves unified timing control of photovoltaic modules under external disturbance conditions by constructing a unified time anchoring chain and correction rhythm, ensuring that the identification and response of each module to the same disturbance event are consistent across the time axis. By marking the disturbance arrival window in the rhythm list and introducing a phase correction factor, the isolation actions of multiple photovoltaic modules are rhythmically coordinated, eliminating the isolation asynchrony problem caused by differences in sampling and response delays. This allows the DC bus voltage to remain continuously changing during the disturbance propagation phase, avoiding high-frequency voltage fluctuations and improving the operational stability and control consistency of the photovoltaic array under dynamic conditions.

[0050] This invention achieves a progressive temporal match between isolation actions and energy flow through the synergistic effect of isolation rhythm frames, balance indices, and phase traction domes. By gradually absorbing and releasing transient energy through the ridge, the inverter reference trajectory achieves smooth convergence under rhythmic guidance. Finally, through breathing-style dynamic regulation, the photovoltaic modules are guided to return to their original positions in stages, ensuring a stable transition of the bus voltage throughout the isolation and recovery process. This effectively prevents inverter control instability caused by sudden energy changes, improving the safety recovery capability and continuous operation reliability of the photovoltaic system. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0052] Figure 1 This is a schematic diagram of the module of the intelligent controller for self-isolating external photovoltaic faults according to the present invention. Detailed Implementation

[0053] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art.

[0054] This invention provides, for example Figure 1 The intelligent controller for self-isolation of photovoltaic external faults shown includes a time anchoring module, a rhythm correction module, an isolation planning module, an energy balance module, a trajectory traction module, and a regression control module.

[0055] The time anchoring module constructs a unified time anchoring chain to track the propagation and arrival order of external disturbances on multiple photovoltaic module sides, generates a time-oriented rhythm list, and marks the arrival window of external disturbances in the rhythm list;

[0056] To achieve synchronous sensing and time unification of multiple photovoltaic modules under external disturbance conditions, a unified time anchoring chain is established to track the propagation and arrival order of external disturbances at each photovoltaic module, thereby generating a time-oriented rhythm list, in which the arrival window of the external disturbance is marked. The specific implementation process is as follows:

[0057] When the photovoltaic system is in stable operation, the input voltage, current frequency, and power fluctuations on the grid side are continuously monitored. When external disturbances occur, such as sudden voltage drops, current surges, reverse power fluctuations, or frequency drift, the onset time of the disturbance is identified by the DC-side voltage change trend of the photovoltaic system, and this moment is used as the starting point of a unified time anchor chain. To ensure the traceability of the unified time anchor chain, a time recording reference is established on each photovoltaic module side to record the first fluctuation instant when the disturbance signal is transmitted from the outside to the input terminal of this module. The recording process includes detecting the voltage change amplitude, direction, and duration at the input terminal, and recording these changes one by one in a time series at fixed time sampling intervals, forming an initial time set of external disturbance propagation across multiple photovoltaic modules. This initial time set, with the start time of the external disturbance as a reference, establishes the order of response of each photovoltaic module to the disturbance.

[0058] After obtaining the time set of external disturbance arrival times for each photovoltaic (PV) module, the disturbance propagation path is physically mapped based on the differences in geographical location, line length, conductor impedance, and connection position to the inverter for each PV module. By comparing the time records of different modules, the actual propagation order of the disturbance along the DC loop is determined. Starting from the module that responds first, the time sequence of the disturbance propagation among the PV modules is arranged sequentially. Subsequently, the time nodes of each PV module are arranged sequentially from the starting point of the external disturbance to the last module, forming a time axis structure with a temporal order. In this time axis structure, each PV module corresponds to a specific disturbance arrival time and relative time interval, which can reflect the temporal characteristics of the external disturbance propagation throughout the DC side, allowing the difference in the perception of the disturbance by each module to be clearly located in the time dimension.

[0059] After obtaining the disturbance propagation timeline structure, a rhythm list is generated by integrating the arrival times and propagation intervals of external disturbances across multiple photovoltaic (PV) modules. The rhythm list is a time-directed table containing sequential and time interval relationships, used to describe the propagation rhythm of external disturbances among multiple PV modules. During the generation of the rhythm list, the arrival time of the disturbance for each PV module is recorded with a specific time value, and the propagation delay interval is calculated between adjacent PV modules. In this way, the rhythm list not only reflects the order of disturbance arrivals but also the temporal continuity and rhythm of disturbance propagation. The generated rhythm list is arranged chronologically, with the first row indicating the start time of the external disturbance and the last row indicating the end time of the disturbance propagation. The arrival times of all PV modules in the propagation path are arranged sequentially in a table, giving the overall temporal structure of disturbance propagation a clear directionality. Thus, the position of each PV module in the rhythm list represents its temporal role in the disturbance propagation chain, providing a quantifiable basis for subsequent time correction and response coordination.

[0060] After generating the rhythm list, the propagation time span of external disturbances on the DC side is further analyzed. Due to the potential influence of conductor length, module spacing, and electromagnetic coupling during disturbance propagation, the time at which each photovoltaic module receives the disturbance signal varies within a certain range. Therefore, the single arrival time in the rhythm list is expanded into a time interval with a start and end point, constructing an external disturbance arrival window. The disturbance arrival window for each photovoltaic module is determined by the start time when the disturbance signal begins to show significant change at the module's input and the end time after the change trend stabilizes. By summarizing the disturbance arrival windows of all photovoltaic modules, the overall time coverage of external disturbance propagation on the DC side is obtained. In the rhythm list, the corresponding disturbance arrival window is marked for each photovoltaic module, ensuring that the rhythm list contains not only propagation sequence information but also time duration information. In this way, the propagation of external disturbances within the photovoltaic system is no longer described as a single point in time but as a continuous time interval, reflecting both the directionality of disturbance propagation and the persistence of the disturbance effect. The resulting rhythm list has a complete temporal correlation, which can serve as a unified temporal basis for subsequent sampling rhythm alignment, phase correction, isolation trigger sequence rearrangement, and energy flow regulation.

[0061] The rhythm correction module performs alignment analysis on the sampling rhythm of multiple photovoltaic modules based on the arrival window of external disturbances marked in the rhythm list, extracts the sampling phase deviation of each photovoltaic module, and condenses the sampling phase deviation to form a phase correction factor. The phase correction factor is used to correct the rhythm list to generate a corrected rhythm.

[0062] To enable multiple photovoltaic (PV) modules to perform data sampling and response control at the same tempo under external disturbances, a detailed alignment analysis of the sampling rhythms of multiple PV modules is required, based on the arrival window of the external disturbance as marked in the rhythm list. This alignment analysis identifies the time offset of each PV module and further extracts the sampling phase deviation of each module. Subsequently, the sampling phase deviations of each PV module are aggregated in an orderly manner to form a unified phase correction factor. This phase correction factor is then used to correct the rhythm list, thereby generating a corrected rhythm that reflects the unified sampling rhythm. The specific implementation steps are as follows:

[0063] Given a known external disturbance arrival window, the sampling behavior of multiple photovoltaic (PV) modules within that window is recorded in detail. Each PV module performs fixed-cycle data sampling during the external disturbance period, sampling voltage, current, and output power changes. Each sampling action is stored chronologically and mapped to the external disturbance arrival window in the rhythm list on the timeline. To ensure the accuracy of the data mapping, the sampling sequence of each PV module is positioned with the start time of the external disturbance arrival window as the time zero point, and the start time, sampling interval length, number of samples, and sampling duration are recorded. In this way, the complete sampling rhythm of each PV module during the external disturbance period can be obtained. The sampling rhythm includes not only the start time of sampling but also the end time of sampling and the time interval between each sample. Thus, the sampling rhythms of all PV modules have clear boundaries and spacing on the timeline, providing a basis for subsequent rhythm alignment.

[0064] After obtaining the time data of the sampling rhythms of all photovoltaic modules, the sampling rhythms of multiple photovoltaic modules are compared and analyzed one by one, using the external disturbance arrival window marked in the rhythm list as a reference. Specifically, the photovoltaic module whose external disturbance arrives first is used as the reference object, and the sampling time series of other photovoltaic modules are compared with the sampling time series of the reference module item by item. The sampling start time difference, sampling interval difference, and sampling end time difference of each photovoltaic module within the same disturbance window are calculated. Through this comparison process, the time misalignment of sampling rhythms of different photovoltaic modules can be clearly identified. For example, when the sampling start time of a photovoltaic module is delayed compared with that of the reference module, the delay time is recorded as a positive offset; if the sampling start time is earlier, it is recorded as a negative offset. The sampling time differences between all photovoltaic modules and the reference module are summarized to form a set of time offset datasets, which fully reflect the differences in the sampling response timing of external disturbances on different photovoltaic module sides. This dataset provides the basis for extracting sampling phase bias.

[0065] After obtaining the time offset dataset of the photovoltaic module sampling rhythm, this time offset data is converted into sampling phase deviation. Sampling phase deviation describes the degree of time displacement of the photovoltaic module's sampling rhythm relative to a reference photovoltaic module and is a key parameter for measuring sampling synchronization. To form a correction basis with global reference significance, the photovoltaic module that responds first on the external disturbance propagation path is used as a fixed reference photovoltaic module, and its sampling rhythm is used as a unified time reference. Then, based on the time offset of each photovoltaic module relative to the reference photovoltaic module, the sampling phase deviations of all photovoltaic modules are arranged sequentially according to the disturbance propagation direction, forming a continuous phase sequence from the first response to the last response. This phase sequence reflects the step-by-step time delay characteristics of the sampling rhythm during the propagation of the external disturbance from the reference photovoltaic module to the last photovoltaic module. By continuously integrating this phase sequence, a correction parameter representing the overall sampling time difference is obtained; this parameter is the phase correction factor. The phase correction factor uses time as the only variable, unifying the expression of the sampling time relationship between photovoltaic modules, making all photovoltaic modules adjustable in the time dimension, and providing a basis for the correction of the rhythm list.

[0066] The original rhythm list is corrected using the generated phase correction factor to generate a corrected rhythm. The correction process uses the time series of the reference photovoltaic module as a fixed benchmark, adjusting the time nodes corresponding to each photovoltaic module in the rhythm list according to the time offset reflected by the phase correction factor. During the adjustment process, if a photovoltaic module is delayed relative to the reference photovoltaic module in the external disturbance propagation path, its time node is shifted forward to the position determined by the phase correction factor; if it is advanced, its time node is shifted backward, aligning the sampling rhythms of all photovoltaic modules on the time axis. After correction, the generated corrected rhythm retains the original order of external disturbance propagation in its time structure while achieving synchronous and unified sampling rhythms. In the corrected rhythm, the sampling time of each photovoltaic module maintains a uniform time interval with the sampling time of the reference photovoltaic module, and the sampling behavior of each module unfolds under the same time benchmark, thereby eliminating response delays or advances caused by differences in sampling periods. The correction rhythm provides a unified time frame for subsequent isolation trigger sequence adjustment, DC energy flow coordination, and synchronous response of inverter control, enabling the photovoltaic system to maintain a coordinated sampling and control rhythm during external disturbances.

[0067] The isolation planning module rearranges the isolation response sequence of multiple photovoltaic modules according to the correction rhythm, constructs a hierarchical isolation trigger sequence, generates an isolation rhythm frame, and uses the isolation rhythm frame to limit the timing boundaries of isolation actions and subsequent energy regulation.

[0068] To ensure that multiple photovoltaic (PV) modules can perform isolation actions in a unified time sequence and coordinated energy release rhythm after an external disturbance, the isolation response sequence of each PV module needs to be rearranged based on the corrected rhythm. This creates a hierarchical isolation trigger sequence, and an isolation rhythm frame is generated accordingly. This rhythm frame clearly defines the start and end range of each layer of isolation action on the timeline, thereby defining the timing boundaries of isolation behavior and subsequent energy regulation. The specific implementation steps are as follows:

[0069] With the calibration rhythm already determined, the response behavior of multiple photovoltaic (PV) modules during external disturbances is time-series processed. Each PV module, upon detecting an external disturbance signal, undergoes four processes: identification, decision-making, driving, and execution. The start and end times of these four processes can be determined using time calibration points within the calibration rhythm. To obtain the actual response sequence of each PV module during external disturbances, the response start times of each PV module are arranged chronologically to form a preliminary isolation response sequence. This sequence records the complete response time trajectory of the external disturbance, starting from the first sensed PV module and proceeding sequentially along the DC loop to the last PV module. By comparing the response start time, isolation drive start time, and power switch completion time of each PV module, the start and end points of the isolation response for each PV module can be accurately determined. The resulting isolation response sequence provides the temporal data basis for subsequent trigger sequence rearrangement, making the temporal relationship of each PV module's actions clearly discernible.

[0070] After obtaining the initial isolation response sequence, the photovoltaic (PV) modules are hierarchically divided based on their physical distribution location in the DC loop, output power level, and impact on the bus voltage. The division process is based on the electrical connection topology of the PV modules. First, the set of PV modules closest to the positive terminal of the DC bus is identified as the first trigger layer. These modules have the greatest impact on voltage stability during the initial stage of bus voltage fluctuations and therefore must be isolated first. Next, the set of PV modules located in the middle of the loop, providing medium power output, is identified as the second trigger layer, used to continue releasing energy in stages after the first layer of isolation. Finally, the set of PV modules closest to the negative terminal of the bus, with lower output power, is identified as the third trigger layer, used to smoothly conclude the energy release process during the overall isolation process. Each layer corresponds to an independent time period. Within this time period, the PV modules within the layer trigger isolation actions sequentially according to the sampling time relationship in the correction rhythm, thus maintaining time coordination within the same layer. This hierarchical division based on power level and location relationship transforms the overall isolation action into a graded process with a sequential order and energy distribution pattern, providing a structured hierarchical basis for subsequent rhythm frame generation.

[0071] After completing the layering, corresponding isolation rhythm frames are generated using the time anchor points in the calibration rhythm as references. The isolation rhythm frame defines the unfolding form of the entire isolation action on the time axis and is a key time frame connecting the isolation actions of each layer with the energy regulation process. The specific process for generating the isolation rhythm frame is as follows: First, determine the start time of each trigger layer. The isolation start time of the earliest responding photovoltaic module in the first trigger layer is used as the starting point of the rhythm frame, and this time value is recorded on the time axis. Second, determine the end time of the first trigger layer's isolation completion; this time serves as the start boundary for the next layer's isolation action. Then, the start and end times of the second and third trigger layers are determined sequentially, with the time interval between each layer determined by the phase spacing reflected in the calibration rhythm. The start and end times of all trigger layers form a stepped structure on the time axis, with each step corresponding to the isolation action process of one photovoltaic module. The rhythm frame not only records the start and end times of each layer's action but also the length of the interlayer transition interval, used for the dynamic connection of the subsequent energy balance process. By using this layer-by-layer stacking method, the isolation rhythm frame can fully reflect the distribution pattern of isolation actions in the time dimension, so that the isolation behavior of each photovoltaic module is carried out within a clear time interval, avoiding time overlap or gaps between multiple layers.

[0072] After the isolation rhythm frame is determined, the time boundaries defined in the rhythm frame are used to limit the timing range of isolation actions and subsequent energy regulation. On the time axis of the rhythm frame, an energy regulation window is formed between the start and end points of each isolation action. This window is used to coordinate the balance between the bus voltage change rate and the output power of the remaining photovoltaic modules. When the photovoltaic modules in the first trigger layer perform isolation actions, the bus voltage will initially drop. At this time, the first energy regulation window is activated in the rhythm frame to adjust the power output of other unisolated photovoltaic modules, keeping the voltage drop rate within a preset range. When the photovoltaic modules in the second trigger layer enter the isolation stage, the second energy regulation window in the rhythm frame begins to function, using the energy released after the previous layer's isolation is completed and the energy difference between the next layer's isolation to achieve a transition balance, ensuring the continuity of the bus voltage during inter-layer transitions. Finally, when the photovoltaic modules in the third trigger layer perform isolation actions, the tail end of the rhythm frame is used as a smooth energy release zone. During this time interval, the bus voltage is gradually stabilized to a safe range, avoiding reverse surges caused by rapid rebounds. In this way, the isolation rhythm frame not only defines the specific triggering sequence and duration of the isolation action of each photovoltaic module, but also provides time boundary constraints for the energy regulation process, so that the isolation behavior and energy distribution are carried out in coordination within the same time frame, thereby achieving controllable management of transient changes on the DC side.

[0073] The energy balance module redistributes the transient energy flow direction on the DC side according to the timing boundary defined by the isolation rhythm frame, constructs a slow-release ridge at the DC bus level, and forms a balance index corresponding to the isolation rhythm frame based on the slow-release ridge.

[0074] To ensure the stability of the DC bus voltage during the isolation process of the photovoltaic system and prevent rapid voltage fluctuations caused by uneven energy release, the flow of transient energy on the DC side needs to be redistributed according to the time boundaries defined by the isolation rhythm frame. This ensures that energy transfer at each stage has temporal coordination and spatial buffering. To achieve this, a buffer ridge is constructed at the DC bus level to absorb the transient energy released by each photovoltaic module during isolation and gradually feed it back to the bus. Subsequently, based on the energy absorption and release patterns of the buffer ridge in each isolation stage, a balance index corresponding to the time structure of the isolation rhythm frame is formed. The specific implementation process is as follows:

[0075] Within the time frame defined by the isolation rhythm, a comprehensive identification and analysis of transient energy flow on the DC side is performed. After an external disturbance triggers isolation, multiple photovoltaic (PV) modules will perform shutdown operations at different times, accompanied by charge release, capacitor energy transfer, and power output changes. To understand the direction and sequence of these energy transfers, continuous monitoring of the output voltage change rate, output current change rate, and bus voltage response of each PV module is required. Based on the hierarchical triggering sequence in the isolation rhythm frame, the energy release sequence of each PV module during isolation is arranged temporally to obtain the propagation path of DC bus energy under external disturbance. In this path, the energy released by the PV module that first performs isolation is rapidly transferred to the bus capacitor, creating a momentary upward or downward trend in the bus voltage; the energy released by the PV modules that subsequently perform isolation has a superposition effect with the previous stage, thus determining the amplitude and duration of the bus voltage change. Through this layer-by-layer identification method, the direction and quantity of transient energy at each stage can be clearly identified, providing a precise basis for subsequent energy redistribution.

[0076] After understanding the transmission patterns of transient energy on the DC side, energy flow is redistributed time-divisionally according to the time boundaries defined in the isolation rhythm frame. The goal of energy redistribution is to maintain the continuity and controllability of energy transmission across different time periods, avoiding large fluctuations in bus voltage caused by concentrated energy release. Specifically, the time interval of each triggering stage in the isolation rhythm frame is divided into multiple energy management sub-intervals, and the energy release and absorption ratios are determined within each sub-interval. Taking the first triggering layer as an example, when the photovoltaic modules in this layer enter the isolation stage, their residual stored energy is released to the bus through the output circuit. To prevent the bus voltage from rising too quickly in a short period, a time period with a high energy absorption ratio is set in this stage, allowing the bus capacitor to absorb most of the transient energy. In the second triggering layer stage, the bus is in an energy balance adjustment state, at which point the energy absorption ratio is reduced, allowing some energy to be naturally conducted to the inverter input. In the third triggering layer stage, the bus mainly performs energy release balancing tasks, smoothing voltage changes by extending the energy release duration. Through this segmented management method, the energy flow of the DC bus throughout the entire isolation cycle becomes regular, thereby achieving energy time coordination during the isolation process.

[0077] After completing the energy distribution structure design, a buffer ridge is constructed at the DC bus level based on the time boundary of the isolation rhythm frame to dynamically buffer energy during each isolation stage. The construction process of the buffer ridge includes three consecutive steps. First, determining the buffer interval. In the isolation rhythm frame, each isolation action has a start time and an end time. The interval between these two time points is defined as the buffer interval, which is used to absorb transient energy in the corresponding stage. Second, establishing the buffer channel. By adjusting the bus capacitor bank, wiring inductance, and bus branch current distribution path, the bus has a high energy absorption capacity in the early stage of energy release, while gradually reducing the energy absorption rate in the later stage of isolation, achieving a rhythmic distribution of energy absorption and release. Third, setting the buffer feedback path. When the buffer ridge reaches a stable state after absorbing energy in the middle of isolation, a portion of the energy is fed back to the main bus through a controlled channel, enabling a smooth transition of the bus voltage between each triggering layer. The buffer ridge operates continuously throughout the entire isolation rhythm frame cycle, participating in the energy absorption and release process during each isolation action, thus forming an energy buffer band covering the entire isolation cycle. The buffer band corresponds strictly to the rhythm frame in time, so that the bus voltage maintains a controllable dynamic stability during the isolation period.

[0078] After the slow-release ridge is formed, a balance index corresponding to the isolation rhythm frame time structure needs to be formed based on its dynamic energy absorption and release characteristics. The balance index is used to describe the energy balance of the DC bus throughout the isolation process and its temporal consistency with the rhythm frame. The process of forming the balance index includes the following three steps: First, record the energy absorption and energy release of the slow-release ridge in the corresponding time period of each isolation layer to obtain the energy change curve. Second, map the energy change curve to the time nodes in the isolation rhythm frame, so that each time node corresponds to an energy change state, thereby establishing a synchronous relationship between the bus energy flow and the isolation action on the time axis. Third, extract key time points as energy balance reference points based on the smoothness and fluctuation range of the energy change curve, and define them as balance index nodes. The balance index nodes are used to constrain the bus voltage change range and serve as a target reference in the subsequent energy regulation stage. Through the existence of the balance index, the transfer of bus energy in different isolation stages is quantitatively controlled, and dynamic balance can be achieved in different stages according to the time pattern of the rhythm frame. Ultimately, the balance index serves as a bridge connecting the isolation rhythm frame and the bus energy regulation, ensuring that the action rhythm in the time dimension is consistent with the flow pattern in the energy dimension, thus achieving unified coordination between isolation control and energy regulation.

[0079] The trajectory traction module tractions and shapes the inverter-side reference operating trajectory based on the balance index, generates a reference trajectory traction belt synchronized with the isolation rhythm frame, enables voltage control and current control to gradually converge according to the correction rhythm, and forms a recovery threshold cable at the end of the reference trajectory traction belt.

[0080] To ensure the smooth convergence and orderly recovery of the control loop on the inverter side after the photovoltaic system completes isolation control and energy redistribution, the reference operating trajectory on the inverter side needs to be shaped based on the balance index. This ensures that the inverter's voltage and current control loops are synchronized with the isolation rhythm frame in time, thus forming a reference trajectory traction band that corresponds to the isolation rhythm frame in the control logic. A recovery threshold is then constructed at the end of this traction band to determine the time range and conditions for inverter control recovery. The specific implementation steps are as follows:

[0081] Based on the established balance index, the current operating status of the inverter is comprehensively captured to determine the deviation between the inverter's voltage control loop and current control loop during the energy coordination phase. The captured parameters include the instantaneous value of the bus voltage, the rate of change of the bus voltage, the transient amplitude and phase change trend of the inverter input current, the time curve of the inverter output power, and the dynamic relationship between bus energy absorption and release. The capture process is synchronized with the balance index, continuously recording various state parameters of the inverter using the time nodes recorded in the balance index as references. By comparing the real-time voltage of the inverter with the target voltage value corresponding to the balance index, it can be determined whether the inverter's energy response is lagging or premature in the current stage. If the inverter input voltage is consistently higher than the corresponding value of the balance index, it indicates that the bus energy release is not yet complete; if it is lower than the corresponding value of the balance index, it indicates that energy recovery is not yet sufficient. Through this continuous capture and comparison, the direction and magnitude of the inverter control loop's deviation on the time axis are clarified, providing a precise reference for subsequent trajectory guidance.

[0082] After understanding the deviation relationship between the inverter control state and the balance index, the inverter reference operating trajectory is traction-shaped according to the time distribution characteristics of the isolation rhythm frame. The core of the reference operating trajectory traction-shaped shaping is to rearrange the original voltage target curve and current target curve of the inverter according to the time dimension, so that they completely correspond to the timing structure of the isolation rhythm frame. During the traction process, the bus energy balance point reflected by the balance index is used as the benchmark, and the rising and falling segments of the voltage reference curve are respectively corresponding to the energy absorption segment and energy release segment in the isolation rhythm frame. Specifically, after the first trigger layer isolation ends, the rate of change of the inverter reference voltage curve should be reduced so that it follows the downward trend of the bus voltage in time to prevent over-response; in the second trigger layer stage, the reference curve maintains a slow upward trend to ensure that the voltage loop's response to the bus voltage change remains linear; after the third trigger layer ends, the reference voltage curve begins to return to the balance value, preparing for the voltage recovery stage. At the same time, the inverter current reference trajectory is adjusted according to the same time frame so that the rate of change of the current is consistent with the phase of the voltage curve, avoiding reverse offset between the two in time. This time-rhythm-based traction shaping enables the reference trajectory and the isolated rhythm frame to be synchronously coupled in the time dimension.

[0083] After the reference trajectory is traction-shaped, the shaping results are continuously unfolded on the time axis to form a reference trajectory traction band with duration characteristics. This traction band consists of two parts: a voltage traction band and a current traction band. The voltage traction band consists of multiple continuous time periods, corresponding to different triggering stages of the isolation rhythm frame. In the first stage, the voltage traction band converges slowly with a decreasing trend to suppress fluctuations in the bus voltage at the initial stage of energy release; in the second stage, the voltage traction band rises gradually, allowing the bus voltage to gradually recover to a stable range; in the third stage, the voltage traction band flattens out, indicating that the bus voltage has entered the steady-state recovery region. The current traction band maintains the same time distribution as the voltage traction band, but its amplitude changes inversely to the voltage curve: in the first stage, the current rises slowly to compensate for energy output; in the second stage, the current gradually decreases to match the bus energy release rate; and in the third stage, it tends to stabilize. By superimposing the voltage and current traction bands, a time-continuous and amplitude-coordinated dual-track control reference structure is formed, enabling the inverter to have rhythmic control guidance after isolation action.

[0084] After the reference trajectory traction band is formed, traction band synchronization constraints are applied to the inverter's voltage control loop and current control loop respectively, enabling them to achieve gradual convergence according to the correction rhythm. The convergence process of the voltage control loop uses the voltage traction band as a dynamic target. By continuously adjusting the output control signal, the actual input voltage of the inverter gradually approaches the target value in the traction band curve, thus achieving a gradual and smooth voltage recovery in time. The convergence process of the current control loop is guided by the current traction band. By controlling the rate and direction of change of the inverter's output current, the current response remains in phase with the voltage curve. During this process, the convergence actions of voltage control and current control use the correction rhythm as a unified time reference, and they adjust synchronously in the time dimension. As time progresses, the deviation between voltage and current gradually decreases, eventually reaching a stable convergence state in the middle of the traction band. Through this rhythmic gradual convergence method, the inverter achieves multi-dimensional coordination in terms of energy, time, and control, avoiding control instability problems caused by rapid voltage rises or current surges during traditional isolation recovery processes.

[0085] At the end of the reference trajectory traction belt, a recovery threshold is formed based on the convergence state of the balance index and the termination boundary of the isolation rhythm frame. The recovery threshold defines the transition time window for the inverter control strategy from the rhythm-guided phase to the normal operation phase. Its formation process includes three steps: First, determining the point in time when the bus voltage remains stable without fluctuations over a continuous period, as the voltage stabilization start time; second, confirming the point in time when the phase deviation between the inverter output current and voltage remains within a set range, as the current stabilization start time; third, combining the above two time points to form the starting position of the recovery threshold, and determining the ending position of the recovery threshold based on the duration of stable bus energy. The time interval of the recovery threshold is the transition interval for the inverter to switch from rhythm-guided control to normal grid-connected operation. Within this interval, the inverter gradually adjusts its output according to the reference trajectory at the end of the traction belt, bringing the voltage and current into a stable synchronized state. When the time interval covered by the recovery threshold ends, the inverter automatically exits rhythm-guided control and enters normal operation mode, thus achieving a natural transition from the isolation control phase to the stable grid-connected phase.

[0086] The reversion control module, based on the dynamic control of the phase traction dome initiated by the recovery threshold cable, performs micro-opening and closing of the isolation channel according to the time structure of the isolation rhythm frame, guiding multiple photovoltaic modules to simultaneously release isolation and revert in segments, so as to suppress control instability caused by DC side voltage collapse and rebound.

[0087] To ensure the photovoltaic system can recover its operating state stably and controllably after the isolation process, a dynamic control process of the phase traction dome needs to be initiated based on the aforementioned recovery threshold. The phase traction dome forms an arched control structure in the time dimension, guiding the micro-opening and closing of the isolation channels of each photovoltaic module along the time axis, enabling each photovoltaic module to synchronously recover its energy output in a rhythmic manner. Through this process, segmented recovery of multiple photovoltaic modules can be achieved without triggering voltage surges, thereby effectively suppressing control instability caused by DC-side voltage collapse and recovery. The specific implementation steps are as follows:

[0088] After the recovery threshold is determined, the time frame for constructing the phase-traction dome is initiated, using the stable time points of the bus voltage and inverter output current as the starting conditions. The existence of the recovery threshold indicates that the bus voltage has entered a controllable range, and the phase difference between the inverter output current and voltage remains within a stable range. At this point, the dome structure is gradually expanded along the positive time axis, with the start time of the recovery threshold as the origin of the dome formation. The dome structure consists of an initial rising segment, a balancing segment, and a convergence segment, with its time span covering the entire recovery phase. The rising segment defines the starting time for the gradual recovery of the photovoltaic modules, the balancing segment maintains the stable range of energy transfer, and the convergence segment guides the system to gradually return to a steady state. The formation of the phase-traction dome marks the beginning of the transition of the photovoltaic system from static isolation to dynamic recovery, and this time frame will serve as a timing reference for the subsequent micro-movements of the isolation channels of each photovoltaic module.

[0089] After the phase-traction dome is established, a micro-opening operation is performed on the isolation channels of each photovoltaic module according to the layered time structure of the isolation rhythm frame. The goal of micro-opening is to gradually make the output voltage of the photovoltaic module converge with the bus voltage, thereby achieving flexible energy injection in the early stage of recovery. In specific implementation, the time point when the last trigger action in the rhythm frame is completed is selected as the starting point for the micro-opening of the first batch of photovoltaic modules. During this period, the conduction angle of the power switch is adjusted to slowly raise the output voltage of the photovoltaic module to 80% to 90% of the bus voltage to prevent energy from being injected too quickly. Subsequently, in the middle period of the dome, the conduction angle is gradually expanded to allow the isolation channels of the second batch of photovoltaic modules to begin conducting, forming time-sharing output. Finally, in the upper period of the dome, the isolation channels of all photovoltaic modules are in a partially conducting state, and the bus voltage transitions from a slow rise to a stable transition. Through this layer-by-layer micro-opening method, the bus voltage presents a gradual climbing curve on the time axis, ensuring that the energy injection process is controllable and avoiding instantaneous voltage surges.

[0090] After the photovoltaic (PV) modules complete their initial startup, phase synchronization traction is implemented under the guidance of a phase traction dome to prevent time drift in the recovery rhythm of each module. Phase synchronization traction ensures that all PV modules maintain the same rhythm during energy recovery. Specifically, the upper time limit of the dome is used as the upper synchronization limit, and the lower time limit is used as the lower synchronization limit. The output voltage rise rate of all PV modules must be controlled within this time envelope. When the output voltage rise rate of a module exceeds the upper limit of the dome, its rise curve is converged towards the interior of the dome by controlling the conduction time delay of its power switch. When the voltage recovery of a module lags behind the lower edge of the dome, the delay is compensated by advancing the conduction time. After multiple rounds of dynamic adjustments, the voltage recovery curves of each PV module are all confined within the dome's time envelope, thus forming a synchronous recovery phase relationship in the time dimension. The purpose of this stage is to ensure that each PV module does not experience independent fluctuations during the energy recovery phase, maintaining the recovery consistency of the entire PV array.

[0091] After the phase recovery of each photovoltaic module is synchronized, breathing-style dynamic control of the isolation channels is required to further balance the energy release rate and the bus absorption rate. Breathing-style control refers to achieving a periodic balance between energy release and absorption by periodically closing and reopening the isolation channels within a short time frame of the phase-traction dome. Specifically, during the middle time interval of the dome, when the bus voltage rises to the median range of the balance index, a portion of the isolation channels is briefly closed, temporarily retaining the bus energy; when the bus voltage drops slightly, the isolation channels are reopened, slowly releasing the retained energy back to the bus. The closing and opening durations of each breathing cycle are set according to the dome's time amplitude ratio, ensuring a one-to-one correspondence between the breathing frequency and the rhythm frame time interval. Breathing-style dynamic control causes small fluctuations in the bus voltage during the recovery phase, thereby eliminating voltage jumps that may be caused by concentrated energy reinjection and achieving smoother and more rhythmic energy release.

[0092] After the breathing-style dynamic control is completed, based on the convergence time structure of the phase-traction dome, a segmented reset operation is performed on each photovoltaic module, gradually returning the entire photovoltaic system to steady-state operation in both time and energy dimensions. The execution sequence of the segmented reset corresponds to the falling edge of the dome, specifically: at the beginning of the falling edge, the first batch of photovoltaic modules is fully turned on, increasing their output power to 50% of the rated value; when the dome enters the middle stage, the second batch of photovoltaic modules is fully turned on, further stabilizing the rise of the bus voltage; when the falling edge of the dome is reached, the remaining photovoltaic modules are fully turned on, synchronizing the output voltage and current of the entire array to a steady state. Afterward, the time envelope of the dome naturally disappears, marking the photovoltaic system's return to grid-connected operation. Through this segmented, layer-by-layer reset method, the photovoltaic system achieves a smooth transition on the time axis, with no voltage abrupt changes or power surges between photovoltaic modules, a continuous and stable bus voltage recovery process, and stable convergence of the inverter control loop within the rhythmic framework.

[0093] Example:

[0094] The intelligent controller for self-isolation of photovoltaic external faults includes a time anchoring unit, a rhythm correction unit, an isolation planning unit, an energy balance unit, a trajectory traction unit, and a recovery control unit. To further improve the accuracy of fault identification and the self-calibration capability of post-fault recovery, differential protection logic, grounding distance protection algorithm, and matching correction information mechanism are introduced on the original basis, enabling the controller to have enhanced diagnostic and self-correcting capabilities throughout the entire process of external disturbance arrival, isolation execution, and system recovery.

[0095] During the operation of the photovoltaic system, the time anchoring unit continuously samples the voltage, current, and power fluctuations on the grid side and identifies the start time of the disturbance signal as the starting point of the time anchoring chain. Multiple photovoltaic modules simultaneously record the time when the external disturbance signal first arrives at the input, forming a set of initial disturbance propagation times. Based on the geographical location, conductor length, and connection location of each module, a time mapping of the disturbance propagation path is established, sequentially arranging the order of disturbance propagation between modules, forming a rhythm list, and marking the disturbance arrival window, thus giving the disturbance propagation process directionality and time span.

[0096] The rhythm correction unit aligns the sampling rhythm of each photovoltaic module based on the disturbance arrival window marked in the rhythm list. The controller records the sampling sequence of voltage, current, and power changes for each module within the external disturbance window, and determines the sampling rhythm with the disturbance start time as the time zero point. Using the photovoltaic module that responds first as the time reference, the sampling start time, interval, and end time of other modules are compared to calculate the sampling time offset and convert it into phase deviation. The phase deviations of each module are arranged according to the disturbance propagation direction to form a phase correction factor, which is used to correct the corresponding time nodes in the rhythm list, generating a correction rhythm, enabling all modules to achieve synchronous sampling and response within the same time frame.

[0097] The isolation planning unit determines the isolation response sequence of the photovoltaic modules based on the correction rhythm, constructs a hierarchical isolation triggering structure, and generates isolation rhythm frames. The photovoltaic modules are divided into three triggering layers according to their position and power level in the DC circuit, corresponding to the positive terminal, middle section, and negative terminal of the bus, respectively. The isolation rhythm frames specify the start and end times of the isolation actions for each triggering layer and set time transition zones between adjacent layers for subsequent energy regulation sequence connection. The isolation rhythm frames form a stepped distribution on the time axis, enabling the isolation actions to be performed in layers and segments, avoiding voltage surges caused by the simultaneous turn-off of multiple modules.

[0098] Within the time frame of the isolation rhythm, the energy balancing unit analyzes and redistributes the transient energy flow of the DC bus in a time-division manner. When an external disturbance triggers isolation, the energy released by each component is transiently transferred through the bus capacitance and wiring inductance. The controller determines the energy absorption and release ratios based on the trigger times of each layer in the rhythm frame and constructs a buffer ridge at the bus level. The buffer ridge is used to absorb and release transient energy at each isolation stage, achieving dynamic energy balance by adjusting the capacitor bank and shunt path. Based on the energy change curve of the buffer ridge in the time dimension, the controller extracts key balance nodes to form balance indices, which are used to constrain the range of bus voltage changes, ensuring that the bus energy flow is consistent with the isolation rhythm.

[0099] Based on energy balance, the trajectory traction unit performs time shaping on the reference trajectories of the inverter-side voltage and current control loops. Using the balance index as a reference, the inverter's voltage and current target curves are synchronized with the isolation rhythm frames in time, generating a reference trajectory traction band. The voltage traction band decreases slowly during the energy release phase and gradually rises and stabilizes during the energy reinjection phase; the current traction band maintains the same time distribution as the voltage traction band but in the opposite direction. The inverter control loop gradually converges with the traction band as the dynamic target, forming a stable rhythmic response. At the end of the traction band, a recovery threshold is formed, using the stabilization time of the bus voltage and inverter output current as the boundary, to define the time interval for the inverter to switch from rhythm-guided control to normal operation.

[0100] After the recovery threshold is determined, the reversion control unit initiates dynamic control of the phase traction dome. The phase traction dome constructs a time frame guided by a time axis, including rising, balancing, and converging segments, performing micro-opening and closing operations on the isolation channels of each photovoltaic module. Under the dome's guidance, each module gradually resumes conduction rhythmically, with the bus voltage showing a continuous upward trend. To maintain synchronization, the controller monitors the voltage recovery curve of each module in real time and achieves phase synchronization by delaying or advancing the conduction time. The middle section of the dome performs breathing-style dynamic control, periodically closing and opening the isolation channels slightly within a short period to achieve a balance between periodic energy release and absorption. Finally, segmented reversion is completed at the dome's falling edge, allowing the entire photovoltaic array to return to steady-state operation.

[0101] To improve the accuracy of isolation and reset actions, differential protection judgment logic and ground distance protection algorithm are introduced in this embodiment. The controller collects current signals at the input and output terminals of each photovoltaic module, forming... , , , Data group. Under normal or external fault conditions, and , and The values ​​are basically equal in magnitude and opposite in direction; when a fault occurs within the zone, the current difference exceeds the set threshold, the controller determines it as a fault within the zone and immediately drives the internal power switch to perform isolation action. At the same time, based on the fixed impedance parameters of the DC line, the grounding distance protection algorithm calculates the distance from the fault point to the module location by measuring the voltage and current change rate, and records the location result in the control dataset, providing a basis for subsequent fault diagnosis and line maintenance.

[0102] Furthermore, to facilitate disconnection detection and wiring correction, matching and correction information is set in each photovoltaic module. This information includes the module number, upstream and downstream connection nodes, and sampling time identifier, and is uploaded synchronously during the rhythm list generation phase. During system operation, the controller periodically compares the matching and correction information of each module. When inconsistencies in upstream and downstream identifiers or signal loss are detected, the controller automatically marks the abnormal module and performs connection correction. This mechanism enables continuous self-checking of line status and automatic disconnection location without affecting normal rhythm operation, providing data support for subsequent maintenance.

[0103] This invention achieves unified timing control of photovoltaic modules under external disturbance conditions by constructing a unified time anchoring chain and correction rhythm, ensuring that the identification and response of each module to the same disturbance event are consistent across the time axis. By marking the disturbance arrival window in the rhythm list and introducing a phase correction factor, the isolation actions of multiple photovoltaic modules are rhythmically coordinated, eliminating the isolation asynchrony problem caused by differences in sampling and response delays. This allows the DC bus voltage to remain continuously changing during the disturbance propagation phase, avoiding high-frequency voltage fluctuations and improving the operational stability and control consistency of the photovoltaic array under dynamic conditions.

[0104] This invention achieves a progressive temporal match between isolation actions and energy flow through the synergistic effect of isolation rhythm frames, balance indices, and phase traction domes. By gradually absorbing and releasing transient energy through the ridge, the inverter reference trajectory achieves smooth convergence under rhythmic guidance. Finally, through breathing-style dynamic regulation, the photovoltaic modules are guided to return to their original positions in stages, ensuring a stable transition of the bus voltage throughout the isolation and recovery process. This effectively prevents inverter control instability caused by sudden energy changes, improving the safety recovery capability and continuous operation reliability of the photovoltaic system.

[0105] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. An intelligent controller for self-isolating photovoltaic external faults, characterized by, The time anchoring module, the rhythm correction module, the isolation planning module, the energy balance module, the trajectory traction module, and the reset control module are included. The time anchoring module constructs a unified time anchoring chain, tracks the propagation order of external disturbances on the side of multiple photovoltaic components, generates a rhythm list and labels the disturbance arrival window. The rhythm correction module aligns the sampling rhythm of each photovoltaic component based on the external disturbance arrival window labeled in the rhythm list, extracts the sampling phase deviation, forms the phase correction factor, and corrects the rhythm list using the phase correction factor to generate a corrected rhythm. The isolation planning module rearranges the isolation response order of the photovoltaic components according to the corrected rhythm, constructs a hierarchical isolation trigger sequence, generates an isolation rhythm frame and limits the timing boundary of the isolation action. The energy balance module redistributes the direct current side transient energy flow according to the timing boundary of the isolation rhythm frame, constructs a slow-release ridge at the bus level and forms a corresponding balance index. The trajectory traction module tractions the reference operation trajectory of the inverter based on the balance index, generates a reference trajectory traction band synchronized with the isolation rhythm frame, makes the voltage control and current control gradually converge according to the corrected rhythm, and forms a recovery threshold curve. The reset control module starts the dynamic control of the phase traction dome based on the recovery threshold curve, implements the micro-opening and closing of the isolation channel according to the time structure of the isolation rhythm frame, and guides the photovoltaic components to be synchronized to remove the isolation and segmented reset.

2. The self-isolating photovoltaic external fault intelligent controller according to claim 1, characterized in that, The steps of generating the rhythm list and labeling the disturbance arrival window are as follows: The input voltage, current frequency and power fluctuation of the power grid side are continuously monitored, and when external disturbance occurs, the disturbance starting time is identified by the direct current side voltage change trend and the time anchoring chain starting point is determined. A time record reference is established on each photovoltaic component side to record the first fluctuation moment when the disturbance signal is transmitted to the component input end and form a disturbance propagation initial time set. According to the geographical position, line length, wire impedance and connection position of each photovoltaic component, the disturbance propagation path is mapped, the time sequence of disturbance propagation is arranged, and a time axis structure is generated. Based on the time axis structure, the disturbance arrival time and propagation interval are integrated to generate a rhythm list, and the disturbance arrival time of each photovoltaic component is extended in the rhythm list to form a time interval with a starting point and an ending point to form a disturbance arrival window.

3. The self-isolating photovoltaic external fault intelligent controller according to claim 2, characterized in that, The steps of generating the corrected rhythm are as follows: The sampling sequence of the voltage change value, current change value and output power change value of multiple photovoltaic components is recorded within the external disturbance arrival window, and the sampling rhythm is determined with the starting time of the external disturbance arrival window as the time zero point. Taking the photovoltaic component that the external disturbance first arrives as the reference object, the sampling time sequence of the remaining photovoltaic components is compared with the sampling time sequence of the reference photovoltaic component, the sampling start time difference, sampling interval difference and sampling end time difference are calculated, and a time offset data set is formed. The time offset data is converted into a sampling phase deviation, arranged in a phase sequence according to the external disturbance propagation direction, and integrated into a phase correction factor. The time nodes of the photovoltaic components in the rhythm list are corrected using the phase correction factor to generate a corrected rhythm.

4. The self-isolating photovoltaic external fault intelligent controller according to claim 3, characterized in that, The steps of generating the isolation rhythm frame are as follows: The identification, decision, driving and execution processes of multiple photovoltaic components during external disturbance are time-sequenced to form a complete isolation response time track and arrange a preliminary isolation response sequence; The photovoltaic components are divided into a first trigger layer close to the positive terminal of the bus, a second trigger layer in the middle section and a third trigger layer close to the negative terminal of the bus according to the physical distribution position of the photovoltaic components in the DC loop, the output power level and the influence intensity on the bus voltage; The start and end times of each trigger layer are determined with reference to the time anchor point of the correction rhythm to generate an isolation rhythm frame and form a step structure on the time axis; The time sequence range of the isolation action and energy regulation is limited according to the time boundary of the isolation rhythm frame, and a continuous energy regulation window is formed between the trigger layers to maintain the stability of the bus voltage.

5. The self-isolating photovoltaic external fault intelligent controller according to claim 4, characterized in that, The time boundary of the isolation rhythm frame and the energy regulation window are continuously connected on the time axis, the end time of each trigger layer is used as the start time of the next trigger layer, and the energy regulation window adjusts the output power of the photovoltaic components during the isolation action to keep the bus voltage change rate within the preset range, thereby realizing the time coordination and balanced transition of the isolation action and energy regulation.

6. The self-isolating photovoltaic external fault intelligent controller according to claim 4, characterized in that, The balance index formation process is as follows: The voltage change rate, current change rate and bus voltage response of multiple photovoltaic components during the isolation process are identified within the time sequence range of the isolation rhythm frame to determine the transfer direction and amount of transient energy; The energy flow direction is time-reallocated according to the layered trigger sequence of the isolation rhythm frame, and the energy absorption ratio and release ratio are set in each layer time interval to maintain the continuity of energy transfer; A slow-release ridge is constructed at the DC bus level, and a dynamic energy buffer band is formed by adjusting the bus capacitor group, wiring inductance and shunt path; Based on the energy absorption and release characteristics of the slow-release ridge, a balance index corresponding to the isolation rhythm frame is formed, and the balance index node is used to constrain the bus voltage change range to maintain energy dynamic balance.

7. The self-isolating photovoltaic external fault intelligent controller according to claim 6, characterized in that, The recovery threshold formation steps are as follows: The operating state of the inverter voltage control loop and current control loop is captured based on the formed balance index, the bus voltage change rate, inverter input current amplitude and phase change trend are recorded, and the control deviation direction is determined; The inverter voltage reference curve and current reference curve are time-rearranged according to the time distribution characteristics of the isolation rhythm frame, so that they are consistent with the energy balance point corresponding to the balance index in time; The reshaped voltage reference curve and current reference curve are unfolded on the time axis to form a voltage traction band and a current traction band synchronized with the isolation rhythm frame; The inverter voltage control loop and current control loop are subjected to synchronous constraints of the traction band, so that they gradually converge according to the correction rhythm and realize synchronous adjustment in time; The recovery threshold is formed at the tail of the reference trajectory traction band according to the convergence state of the balance index and the termination boundary of the isolation rhythm frame, which is used to determine the transition time window of the inverter from rhythm-guided control to normal operation.

8. The self-isolating photovoltaic external fault intelligent controller according to claim 7, characterized in that, The formation of the recovery threshold is based on the starting time of bus voltage stabilization and the phase stabilization time of inverter output current. The starting and ending intervals of the recovery threshold are determined by detecting the balance of bus energy in continuous time. In the interval, the inverter gradually adjusts the output according to the reference trajectory of the traction belt end section, so that the voltage and current are kept synchronized and stable, and automatically switch to normal grid-connected operation after the end of the threshold.

9. The self-isolating photovoltaic external fault intelligent controller according to claim 7, wherein, Based on the dynamic regulation of the recovery threshold, the isolation channel is opened and closed in a small amplitude according to the time structure of the isolation rhythm frame, and the photovoltaic components are guided to be synchronized to remove the isolation and segmented to return as follows: After the recovery threshold is determined, the stable time points of the bus voltage and the inverter output current are used as the starting conditions to construct a phase traction dome time frame along the positive direction of the time axis, which includes the rising section, the balance section and the convergence section; According to the hierarchical time structure of the isolation rhythm frame, the isolation channel of each photovoltaic component is executed in a small amplitude, and the output voltage of the photovoltaic component is gradually adjusted to be consistent with the bus voltage by adjusting the conduction angle of the power switch; Under the guidance of the phase traction dome, the phase synchronization traction is implemented, and the voltage recovery curve of each photovoltaic component is limited in the dome time envelope to realize synchronous recovery by delaying or advancing the conduction time; In the middle section of the dome, the isolation channel is executed in a breathing dynamic control, and the energy cycle release and absorption balance are realized by periodic small amplitude closing and opening; According to the convergence section time structure of the phase traction dome, the segmented return operation is executed, so that the photovoltaic components are gradually recovered and returned to stable operation in time and energy dimensions.

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