Photovoltaic turn-off device starting control method and related device

Abstract

The invention provides a photovoltaic turn-off device starting control method and a related device, and relates to the field of photovoltaic technology, the method is applied to a controller in a photovoltaic turn-off device, and the photovoltaic turn-off device further comprises a first switch tube and a second switch tube which are connected with the controller. And the first switching tube and the second switching tube respectively control the on-off of the two paths of photovoltaic module loops. The starting control method of the photovoltaic turn-off device comprises the following steps: when a switch tube conduction instruction is received, judging whether the current working condition is a weak light starting working condition or not; and if the current working condition is the weak light starting working condition, the first switching tube is firstly switched on in a random delay manner, and after the first switching tube is switched on, the second switching tube is switched on in a random delay manner. After the first switch tube is switched on or the two switch tubes are switched on, the on-off states of the two switch tubes are controlled according to the current input end voltage of the photovoltaic turn-off device, so that the power failure restart phenomenon of the photovoltaic turn-off device under the weak light working condition is reduced, the stable operation of the turn-off device is ensured, and the overall operation reliability of a photovoltaic system is improved.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and more specifically, to a photovoltaic shutdown start-up control method and related apparatus. Background Technology

[0002] In distributed photovoltaic (PV) power generation systems, PV power switches are key devices for ensuring component-level safety. They need to work with inverters to achieve circuit switching and fault protection functions, and their operational stability will directly affect the startup reliability of the PV system.

[0003] However, under low-light conditions such as early morning and late evening when sunlight intensity is insufficient, when the output voltage and power of the photovoltaic modules are at the critical state of the shutdown circuit breaker's operating threshold, the instantaneous load generated when the switching transistors in the shutdown circuit breaker turn on will pull the module voltage below the shutdown circuit breaker's operating voltage, causing the shutdown circuit breaker to fail to start normally. This, in turn, leads to communication interruption and data upload failure between the shutdown circuit breaker and the main data acquisition equipment. This phenomenon is particularly pronounced in photovoltaic shutdown circuit breakers using a one-to-two architecture, as the instantaneous load generated by the simultaneous conduction of two switching transistors is more likely to cause a voltage drop in the modules. Prolonged operation in this state will significantly affect the lifespan of the shutdown circuit breaker. Furthermore, during the photovoltaic system startup phase, when the inverter and shutdown circuit breaker start simultaneously, the sudden drop in string voltage caused by the inverter startup process will also cause the shutdown circuit breaker to malfunction.

[0004] In summary, how to reduce the phenomenon of photovoltaic power outage restarts under low light conditions, ensure the stable operation of the power outage device, and thus improve the overall reliability of the photovoltaic system is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to provide a photovoltaic shutdown switch start-up control method and related device to reduce the phenomenon of photovoltaic shutdown switch restart under low light conditions, ensure stable operation of the shutdown switch, and thus improve the overall reliability of photovoltaic system operation.

[0006] To achieve the above objectives, the technical solution adopted in this application is as follows: In a first aspect, this application provides a photovoltaic (PV) shutdown switch start-up control method, applied to a controller in a PV shutdown switch, wherein the PV shutdown switch further includes a first switching transistor and a second switching transistor; the controller is connected to the first switching transistor and the second switching transistor respectively; the first switching transistor and the second switching transistor are respectively used to control the on / off state of two PV module circuits; the method includes: When a switch transistor is turned on, it is determined whether the current operating condition is a low-light start-up condition. If the current operation is in a low light start-up condition, the first switch is turned on after a random delay, and the second switch is turned on after a random delay after the first switch is turned on. After the first switch is turned on or both switches are turned on, the on / off state of the two switches is controlled according to the current input voltage of the photovoltaic switch.

[0007] Furthermore, the photovoltaic shutdown device also includes a voltage comparison module connected to the controller; the voltage comparison module is used to detect the current input voltage of the photovoltaic shutdown device in real time, and output a warning signal when the current input voltage is less than a preset low-voltage protection threshold; the step of controlling the on / off state of the two switching transistors according to the current input voltage of the photovoltaic shutdown device after the first switching transistor is turned on or after both switching transistors are turned on includes: If the warning signal sent by the voltage comparison module is received after the first switch is turned on or after both switches are turned on, the already turned-on switch is turned off. Repeat the steps of randomly delaying the switching transistor to control the switching state of the transistor according to the current input voltage of the photovoltaic switch until the photovoltaic system enters a stable state or receives a switch-off command.

[0008] Furthermore, if the warning signal sent by the voltage comparison module is received, the step of turning off the already turned-on switching transistor includes: If the warning signal sent by the voltage comparison module is received in multiple consecutive sampling periods, it is determined to be a valid low voltage alarm, and the already turned-on switching transistor is turned off.

[0009] Furthermore, the step of controlling the on / off state of the two switching transistors based on the current input voltage of the photovoltaic switch after the first switching transistor is turned on or after both switching transistors are turned on also includes: After both switching transistors are turned on, if no warning signal is received within a preset time period, the photovoltaic system is determined to have entered a stable state, and the first and second switching transistors are controlled to remain in a continuously conducting state to complete the startup of the photovoltaic shutdown device.

[0010] Furthermore, if the current operation is in a low-light start-up condition, the steps of first randomly delaying the conduction of the first switch, and then randomly delaying the conduction of the second switch after the first switch is conducted, include: Under the current low light start-up condition, a random number seed is generated based on the unique identifier of the photovoltaic shut-off device; Based on the random number seed, a first random delay value and a second random delay value are generated; The first switch is controlled to turn on after a delay of the first random delay value, and after the first switch is turned on, the second switch is controlled to turn on after a delay of the second random delay value.

[0011] Furthermore, when a switch-on command is received, the steps for determining whether the current operating condition is a low-light start-up condition include: After receiving the switch tube turn-on command, the current input voltage and historical power outage records of the photovoltaic power cut-off device are obtained; If the current input voltage is less than the preset low light voltage threshold, or if the historical power outage records indicate that there are more than a predetermined number of power outage events in the current time period, then the current state is determined to be low light start-up mode. If the current input voltage is greater than or equal to the preset low light voltage threshold, and the historical power outage records indicate that there are no more than a predetermined number of power outage events in the current time period, then the current operation is determined to be in normal startup condition.

[0012] Furthermore, after determining whether the current operating condition is a low-light start-up condition, the method further includes: If the current operation is in normal startup condition, the first switch and the second switch are directly turned on.

[0013] Secondly, this application also provides a photovoltaic shutdown device for starting control, applied to a controller in a photovoltaic shutdown device, wherein the photovoltaic shutdown device further includes a first switching transistor and a second switching transistor; the controller is connected to the first switching transistor and the second switching transistor respectively; the first switching transistor and the second switching transistor are respectively used to control the on / off state of two photovoltaic module circuits; the device is used to execute the photovoltaic shutdown device starting control method as described in any one of the first aspects, the device comprising: The judgment module is used to determine whether the current state is a low light start-up condition when a switch tube is turned on. The delayed-on module is used to first randomly delay the on-time of the first switch transistor when the current low-light start-up condition is met, and then randomly delay the on-time of the second switch transistor after the first switch transistor is turned on. The control module is used to control the on / off state of the two switching transistors according to the current input voltage of the photovoltaic switch after the first switching transistor is turned on or after both switching transistors are turned on.

[0014] Thirdly, this application also provides an electronic device, including a processor and a memory, the memory storing a computer program executable by the processor, the processor being able to execute the computer program to implement the photovoltaic shutdown start-up control method as described in any of the first aspects.

[0015] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the photovoltaic shutdown start-up control method as described in any of the first aspects.

[0016] Compared with the prior art, this application has the following advantages: The photovoltaic shutdown control method provided in this application combines a "step-by-step random delay conduction" strategy with an "input voltage feedback control" strategy, effectively mitigating the problem of shutdown restart due to instantaneous load surges under low light conditions. Specifically, by employing a step-by-step random delay conduction strategy, this application avoids the instantaneous load superposition caused by the simultaneous conduction of two switching transistors under low light startup conditions, effectively reducing the risk of the photovoltaic module output voltage being pulled down. At the same time, the random delay conduction method allows the current path establishment process of multiple photovoltaic shutdown devices in the same photovoltaic string to be naturally staggered in time, avoiding the instantaneous voltage collapse of the string caused by multiple photovoltaic shutdown devices drawing power at the same time, ensuring that the voltage fluctuation of the same string is within a controllable range, and reducing the overall startup inrush current of the string. Furthermore, after the first switch is turned on or both switches are turned on, this application adopts an input voltage feedback control strategy. The controller continuously monitors the current input voltage of the photovoltaic power cut-off device and dynamically adjusts the on / off state of each switch accordingly. This achieves adaptive matching between load behavior and power supply capacity, forming a "pulse-type energy storage" effect, gradually raising the photovoltaic system voltage to a stable level. This effectively reduces the power failure and restart phenomenon of the photovoltaic power cut-off device in low light environments, ensuring its startup success rate and operational stability in low light environments, thereby improving the overall reliability of the photovoltaic system. Attached Figure Description

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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, not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0018] Figure 1 This application provides a schematic diagram of the structure of a distributed photovoltaic system. Figure 2 One of the flowcharts for a photovoltaic shutdown start-up control method provided in this application; Figure 3 A second schematic flowchart of a photovoltaic shutdown device start-up control method provided in this application; Figure 4 The third flowchart illustrating a photovoltaic shutdown start-up control method provided in this application; Figure 5 The fourth flowchart illustrating a photovoltaic shutdown start-up control method provided in this application; Figure 6 A circuit diagram of a voltage comparison module provided in this application; Figure 7 The fifth flowchart illustrating a photovoltaic shutdown start-up control method provided in this application; Figure 8 This application provides a structural block diagram of a photovoltaic shutdown start-up control device.

[0019] Icons: 10-Photovoltaic shutdown start control device; 11-Judgment module; 12-Delayed conduction module; 13-Control module. Detailed Implementation

[0020] 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. The components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, 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 process, method, article, or apparatus.

[0023] like Figure 1 As shown, in distributed photovoltaic (PV) systems, a one-to-two architecture PV switch is commonly used, where two PV modules share one switch. The outputs of each switch are connected in series to form a PV string, which is ultimately connected to the DC input of the inverter. This type of PV switch integrates two switching transistors to synchronously control the on / off state of the two PV modules it is connected to. Furthermore, the PV switch is directly powered by the PV modules it is connected to, achieving self-powered operation.

[0024] However, under low-light conditions (early morning and evening) with insufficient sunlight, the voltage and power output of the photovoltaic modules are within the critical range of the normal operating threshold of the shutdown circuit breaker. When two switching transistors are turned on simultaneously, a large instantaneous load current is generated, causing the module terminal voltage to drop rapidly, even below the minimum operating voltage of the shutdown circuit breaker, thus triggering a power outage or restart of the shutdown circuit breaker, making it unable to maintain normal operation. Furthermore, during the system startup process in the early morning, the inverter and multiple shutdown circuit breakers will start synchronously. Because the inverter performs Maximum Power Point Tracking (MPPT) operation during startup, it causes a momentary drop in the photovoltaic string voltage, similarly leading to instability in the shutdown circuit breaker's supply voltage, making it difficult to start reliably. Therefore, how to reduce the power outage and restart phenomenon of photovoltaic shutdown circuit breakers under low-light conditions, ensure stable operation of the shutdown circuit breakers, and thus improve the overall reliability of the photovoltaic system, is a technical problem that urgently needs to be solved by those skilled in the art.

[0025] To address the aforementioned technical problems, this application provides a photovoltaic (PV) switch start-up control method. This method is applied to the controller in each PV switch of a photovoltaic system, and each PV switch further includes a first switching transistor and a second switching transistor. The controller is connected to both the first and second switching transistors, which are used to control the on / off switching of two PV module circuits.

[0026] like Figure 2 As shown, the photovoltaic shutdown start-up control method provided in this application includes the following steps: Step S100: When a switch tube is turned on, determine whether the current state is a low light start-up condition.

[0027] In step S200, if the current state is a low light start-up condition, the first switch is turned on after a random delay, and the second switch is turned on after a random delay after the first switch is turned on.

[0028] In step S300, after the first switch is turned on or both switches are turned on, the on / off state of the two switches is controlled according to the current input voltage of the photovoltaic switch. The current input voltage of the photovoltaic switch reflects the current output voltage level and light intensity of the connected photovoltaic module.

[0029] Therefore, this application effectively mitigates the power-off restart problem caused by instantaneous load surges under low-light conditions by combining a "two-stage random delay turn-on" strategy with "input voltage feedback control." Specifically, when the system is detected to be in a low-light start-up condition, the controller does not immediately turn on both switches simultaneously. Instead, it uses a random delay to turn on the first and second switches in stages, avoiding the instantaneous load superposition caused by the simultaneous turn-on of the two switches and reducing the risk of the module output voltage being pulled down under low-light conditions. At the same time, the random delay turn-on method naturally staggers the current path establishment process of multiple photovoltaic turn-off devices in the same photovoltaic string, avoiding the instantaneous voltage collapse of the string caused by multiple photovoltaic turn-off devices drawing power at the same time. This ensures that the voltage fluctuation of the same string is within a controllable range and reduces the overall start-up inrush current of the string. Furthermore, after the first switch is turned on or both switches are turned on, the controller continuously monitors the current input voltage of the photovoltaic power cut-off device and dynamically adjusts the on / off state of each switch accordingly. This achieves adaptive matching between load behavior and power supply capacity, forming a "pulse-type energy storage" effect. This gradually raises the photovoltaic system voltage to a stable level, effectively reducing the power failure and restart phenomenon of the photovoltaic power cut-off device in low light environments. It ensures the success rate of its start-up and operational stability in low light environments, thereby improving the overall reliability of the photovoltaic system.

[0030] As can be seen, both the above-mentioned two-stage random delay turn-on strategy and input voltage feedback control strategy are triggered and executed under the premise that the system is currently in a low-light start-up condition; if the system is not currently in a low-light start-up condition, different start-up control methods are adopted to balance the response speed and operating efficiency under normal lighting conditions.

[0031] To better understand this, the determination mechanism for low-light start-up conditions will be explained in detail below. In one alternative implementation, please refer to Figure 3 When a switch tube is received to turn on, the step S100 of determining whether the current state is under weak light start-up condition includes sub-steps S110, S120 and S130.

[0032] Step S110: After receiving the switch tube turn-on command, obtain the current input voltage and historical power outage records of the photovoltaic power cut-off device.

[0033] Step S120: If the current input voltage is less than the preset low light voltage threshold, or if the historical power outage records indicate that there are more than a predetermined number of power outage events in the current time period, then it is determined that the current state is in low light start-up mode.

[0034] Understandably, if the current input voltage is less than the preset low-light voltage threshold, it indicates that the current light intensity is weak, the photovoltaic module output voltage is low, and the photovoltaic shutdown device is in a critical operating state. It is prone to repeated start-stop cycles or operational instability due to light fluctuations or load changes, and this is considered a low-light start-up condition. If historical power outage records indicate that there have been more than a predetermined number of power outages in the current period, it indicates frequent fluctuations in the recent power supply environment, possibly due to intermittent shading, cloud movement, low light levels in the morning and evening, or poor connection issues. This causes the shutdown device to experience multiple power outages and restarts, reflecting that the current period is not a stable power generation window, and this should also be considered a low-light start-up condition. This judgment logic ensures that the controller adopts a more cautious low-light start-up strategy when power supply is insufficient or the equipment has a recent history of instability, thus covering all high-risk scenarios that may lead to start-up failure.

[0035] Step S130: If the current input voltage is greater than or equal to the preset low light voltage threshold, and it is determined from the historical power outage records that there are no more than a predetermined number of power outage events in the current time period, then it is determined that the current state is in normal startup condition.

[0036] Understandably, if the current input voltage of the photovoltaic switch is sufficient and its historical operating status is stable, it indicates that the current lighting conditions are good and that it has the power and environmental foundation for normal startup. This is considered a normal startup condition.

[0037] Therefore, by combining real-time voltage detection with historical operating status analysis, this application can more comprehensively and accurately distinguish between normal operating conditions that truly have continuous power generation capabilities and edge low light scenarios that only briefly recover, thereby improving the adaptive control capability and operational stability of photovoltaic power switches in complex environments.

[0038] Furthermore, in another alternative implementation, please refer to... Figure 4 After step S100, which determines whether the current operating condition is a low-light start-up condition, the photovoltaic shutdown control method provided in this application embodiment further includes: In step S400, if the current operating condition is normal startup, the first and second switching transistors are directly turned on.

[0039] Under normal startup conditions, the input voltage of the photovoltaic shutdown device is sufficient and the power supply environment is stable, so there is no need to adopt a protective delay strategy. At this time, directly controlling the first and second switching transistors to conduct synchronously can achieve rapid power-on and energy transfer, shorten the overall startup time of the photovoltaic system, and thus improve response efficiency and power generation utilization.

[0040] To better understand the technical solution of this application, the control logic and processing strategy under low light start-up conditions will be explained in detail below.

[0041] In one alternative implementation, please refer to Figure 5 If the current state is a low light start-up condition, the step S200, which involves first randomly delaying the conduction of the first switch and then randomly delaying the conduction of the second switch after the first switch is turned on, includes sub-steps S210, S220 and S230.

[0042] Step S210: Under the current weak light start-up condition, generate a random number seed based on the unique identifier of the photovoltaic shut-off device.

[0043] Step S220: Based on the random number seed, generate a first random delay value and a second random delay value. The first and second random delay values ​​are limited to a preset time range to avoid infinite delay and ensure the system starts up within a reasonable time.

[0044] Step S230: Control the first switch to turn on after a first random delay value, and after the first switch is turned on, control the second switch to turn on after a second random delay value.

[0045] Understandably, each photovoltaic (PV) switch has a unique and unchangeable hardware identifier. By generating a random number seed based on the unique identifier of the PV switch and determining the step-by-step turn-on delay time of each switch accordingly, differentiated and decentralized startup timing control can be achieved in low-light environments. Since the identifiers of each PV switch are different, the generated random delay values ​​are also different, thus preventing multiple PV switches in the same string from starting simultaneously under the same low-light conditions, which could pull down the string voltage and improve the overall stability and power supply reliability of the system. Furthermore, the random delay turn-on mechanism can reduce the risk of resonant power outages caused by periodic synchronization behavior among multiple devices, making it particularly suitable for distributed deployment and large-scale gridded PV systems.

[0046] In one optional implementation, the photovoltaic shutdown device further includes a voltage comparison module connected to the controller. This voltage comparison module is used to detect the current input voltage of the photovoltaic shutdown device in real time and send a warning signal to the controller when the current input voltage is less than a preset low-voltage protection threshold. Specifically, the photovoltaic shutdown device's start-up voltage is less than the preset low-voltage protection threshold and less than the stable operating voltage under normal power generation conditions.

[0047] For example, please refer to Figure 6 The voltage comparison module consists of a voltage comparator, multiple resistors, and capacitors. The voltage comparator has two input pins (non-inverting input IN+ and inverting input IN-) and one output pin OUT. The non-inverting input IN+ is connected to the input of the photovoltaic switch to acquire the current input voltage of the photovoltaic switch in real time (i.e.,...). The inverting input IN- is connected to the reference voltage (i.e., the preset low-voltage protection threshold); the output pin OUT is connected to the controller and is used to output the comparison result (i.e., ...). The data is transmitted to the controller in real time.

[0048] If the current input voltage If the voltage is ≥ the preset low-voltage protection threshold, it indicates that the component is powered normally, and the voltage comparator outputs a low level to the controller; if the current input voltage is ≥ the preset low-voltage protection threshold, it indicates that the component is powered normally, and the voltage comparator outputs a low level to the controller. If the preset low-voltage protection threshold is less than the threshold, it indicates that there is a risk of insufficient power supply to the components. The voltage comparator outputs a high level to the controller as a warning signal.

[0049] Further, please refer to Figure 7 The step S300, which controls the on / off state of the two switching transistors according to the current input voltage of the photovoltaic switch after the first switching transistor is turned on or after both switching transistors are turned on, includes sub-steps S310 and S320.

[0050] Step S310: After the first switch is turned on or after both switches are turned on, if a warning signal is received from the voltage comparison module, the already turned-on switch is turned off.

[0051] Step S320: Repeat the steps of randomly delaying the switching transistor to control the switching state of the transistor according to the current input voltage of the photovoltaic switch, until the photovoltaic system enters a stable state or receives a switching transistor turn-off command.

[0052] Understandably, after the first switch is turned on or both switches are turned on, if the current input voltage of the photovoltaic switch (i.e., the photovoltaic module voltage) is pulled down below the preset low-voltage protection threshold by the load, the voltage comparison module can quickly detect this and send a warning signal. The controller then turns off the already turned-on switches. Because the turn-on time is extremely short and the amount of electricity drawn from the module is small, the module voltage only drops slightly and does not decrease to the photovoltaic switch's startup voltage, thus preventing the photovoltaic switch from completely losing power.

[0053] Based on this, by repeatedly executing frequent switching operations of "random delayed turn-on - voltage monitoring - abnormal turn-off," the load is intermittently connected in a pulse manner, gradually transferring electrical energy to downstream circuits (such as the inverter DC bus). As electrical energy gradually accumulates, the bus voltage gradually rises and tends to stabilize, providing continuous power supply conditions for the inverter's internal control circuit, enabling its MPPT algorithm to start and enter a smooth tracking state. With the inverter-side voltage stabilizing and the inverter MPPT starting to work, the entire photovoltaic system will enter a relatively stable operating state. It can be seen that this application achieves "energy accumulation start-up" under low light conditions through hardware comparison and software control synergy, effectively improving the adaptability and start-up success rate of photovoltaic shut-off devices in low light intensity and high fluctuation environments.

[0054] In addition, due to noise interference or instantaneous voltage fluctuations in the actual application environment, these non-continuous abnormal signals may cause the protection mechanism to be falsely triggered, resulting in unnecessary frequent shutdown of the switching transistor, which affects the system stability and normal operation.

[0055] To avoid malfunctions caused by brief, accidental voltage disturbances, in one optional embodiment, if a warning signal is received from the voltage comparison module, the step S310 of turning off the already turned-on switch includes: if a warning signal is received from the voltage comparison module in multiple consecutive sampling periods, it is determined to be a valid low-voltage alarm, and the already turned-on switch is turned off.

[0056] Therefore, by introducing a multi-cycle continuous detection mechanism, this application can effectively distinguish between real component voltage deficiency and transient interference, which not only improves the system's robustness in complex electromagnetic environments, but also reduces the risk of system interruption caused by false protection and enhances the reliability of the overall control logic.

[0057] Furthermore, step S300, which controls the on / off state of the two switches based on the current input voltage of the photovoltaic switch after the first switch is turned on or after both switches are turned on, also includes: After both switching transistors are turned on, if no warning signal is received within a preset time, the photovoltaic system is determined to have entered a stable state, and the first and second switching transistors are controlled to remain in a continuously conducting state to complete the start-up of the photovoltaic shutdown device.

[0058] Understandably, if no warning signal is received from the voltage comparison module within a preset time after both switches are turned on, it indicates that the current input voltage (i.e., the module voltage) is stable, the photovoltaic power cut-off switch has not caused a voltage drop during the process of drawing power from the module, and the system's power supply capacity is sufficient to meet the conditions for continuous operation. At this time, it is determined that the photovoltaic system has entered a stable state, and the controller can release the trial control mode (i.e., frequent switching operation) and switch the first and second switches to the continuous conduction state to complete the startup process.

[0059] This mechanism dynamically verifies the voltage maintenance capability after both switches are turned on by setting a "stability observation window" (i.e., a preset duration), avoiding the misjudgment of long-term stability based solely on instantaneous voltage compliance. Only when the input voltage consistently exceeds the preset low-voltage protection threshold for a continuous period is it considered that the lighting conditions are sufficient to support the normal operation of downstream equipment such as the inverter, and that the MPPT can operate smoothly, thus ultimately confirming successful startup. This design not only improves the accuracy of system judgment but also enhances the anti-interference capability in low-light fluctuation environments, achieving a smooth transition from "trial startup" to "reliable operation."

[0060] In summary, the photovoltaic shutdown start-up control method provided in this application solves the problem of photovoltaic shutdown devices restarting due to instantaneous load surges in low-light environments by constructing a full-link adaptive control mechanism of "operating condition identification—step-by-step delayed conduction—voltage closed-loop feedback—stability confirmation". Specifically, the method first accurately identifies the low-light start-up condition based on the dual criteria of real-time input voltage (i.e., module voltage) and historical power outage records, avoiding misjudging a brief voltage rebound as a stable power generation condition. After determining that the condition is a low-light start-up condition, a random number seed generation mechanism based on the unique identifier of the photovoltaic shutdown device is used to achieve differentiated delayed control of the conduction sequence of the switching transistors in each photovoltaic shutdown device, effectively staggering the power-taking time of multiple shutdown devices in the string and suppressing voltage collapse caused by concentrated loads. Next, by introducing a fast response mechanism that coordinates the voltage comparison module with the controller, the already conducting switching transistor is dynamically turned off when the input voltage is detected to be lower than the preset low voltage protection threshold. Combined with multi-sampling cycle continuous judgment logic to eliminate instantaneous interference and false judgment, reliable identification and rapid protection against real undervoltage risks are achieved.

[0061] Based on this, a pulsed energy accumulation strategy that cyclically executes "random delayed turn-on—voltage monitoring—abnormal turn-off" gradually raises the DC bus voltage of the photovoltaic system under low light conditions, supporting the inverter to complete MPPT startup and enter a stable operating state. After both switches are turned on, a preset stability observation window is set. Only when the voltage remains consistently above a preset low-voltage protection threshold does the system enter continuous conduction mode, ultimately completing the entire startup process. This application can reduce the phenomenon of photovoltaic power-off restarts under low light conditions, ensuring stable operation of the power-off device and thus improving the overall reliability of the photovoltaic system.

[0062] Based on the above methodological concept, in one optional implementation, please refer to... Figure 8This application also provides a photovoltaic shutdown start-up control device 10, applied to a controller in a photovoltaic shutdown device. The photovoltaic shutdown device further includes a first switching transistor and a second switching transistor. The controller is connected to both the first and second switching transistors, which are used to control the on / off switching of two photovoltaic module circuits. The photovoltaic shutdown start-up control device 10 is used to execute the photovoltaic shutdown start-up control method as described in any of the foregoing embodiments. The device includes: The judgment module 11 is used to determine whether the current state is a weak light start-up condition when a switch tube is turned on.

[0063] The delayed-on module 12 is used to first randomly delay the first switch transistor when the current low light start-up condition is met, and then randomly delay the second switch transistor after the first switch transistor is turned on.

[0064] The control module 13 is used to control the on / off state of the two switching transistors according to the current input voltage of the photovoltaic switch after the first switching transistor is turned on or after both switching transistors are turned on.

[0065] Specific limitations regarding the photovoltaic shutdown start-up control device 10 can be found in the limitations of the photovoltaic shutdown start-up control method described above, and will not be repeated here. Each module in the photovoltaic shutdown start-up control device 10 can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in the electronic device, or stored in the memory of the electronic device in software form, so that the processor can call and execute the corresponding operations of each module.

[0066] Furthermore, embodiments of this application also provide an electronic device, including a processor and a memory, wherein the memory stores a computer program that can be executed by the processor, and the processor can execute the computer program to implement the photovoltaic shutdown start-up control method as described in any of the foregoing embodiments.

[0067] Furthermore, embodiments of this application also provide a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the photovoltaic shutdown start-up control method as described in any of the foregoing embodiments.

[0068] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0069] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0070] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A photovoltaic shutdown switch start-up control method, characterized in that, A controller is applied in a photovoltaic (PV) shutdown device, the PV shutdown device further including a first switching transistor and a second switching transistor; the controller is connected to the first switching transistor and the second switching transistor respectively; the first switching transistor and the second switching transistor are used to control the on / off state of two PV module circuits respectively; the method includes: When a switch transistor is turned on, it is determined whether the current operating condition is a low-light start-up condition. If the current operation is in a low light start-up condition, the first switch is turned on after a random delay, and the second switch is turned on after a random delay after the first switch is turned on. After the first switch is turned on or both switches are turned on, the on / off state of the two switches is controlled according to the current input voltage of the photovoltaic switch.

2. The photovoltaic shutdown start-up control method according to claim 1, characterized in that, The photovoltaic shutdown device also includes a voltage comparison module connected to the controller; the voltage comparison module is used to detect the current input voltage of the photovoltaic shutdown device in real time, and output a warning signal when the current input voltage is less than a preset low voltage protection threshold. After the first switch is turned on, or after both switches are turned on, the steps of controlling the on / off state of the two switches according to the current input voltage of the photovoltaic switch include: If the warning signal sent by the voltage comparison module is received after the first switch is turned on or after both switches are turned on, the already turned-on switch is turned off. Repeat the steps of randomly delaying the switching transistor to control the switching state of the transistor according to the current input voltage of the photovoltaic switch until the photovoltaic system enters a stable state or receives a switch-off command.

3. The photovoltaic shutdown start-up control method according to claim 2, characterized in that, If the warning signal sent by the voltage comparison module is received, the step of turning off the already turned-on switching transistor includes: If the warning signal sent by the voltage comparison module is received in multiple consecutive sampling periods, it is determined to be a valid low voltage alarm, and the already turned-on switching transistor is turned off.

4. The photovoltaic shutdown start-up control method according to claim 2, characterized in that, After the first switch is turned on or both switches are turned on, the step of controlling the on / off state of the two switches based on the current input voltage of the photovoltaic switch further includes: After both switching transistors are turned on, if no warning signal is received within a preset time period, the photovoltaic system is determined to have entered a stable state, and the first and second switching transistors are controlled to remain in a continuously conducting state to complete the startup of the photovoltaic shutdown device.

5. The photovoltaic shutdown start-up control method according to claim 1, characterized in that, If the current operation is in a low-light start-up condition, the steps of first randomly delaying the conduction of the first switch, and then randomly delaying the conduction of the second switch after the first switch is conducted include: Under the current low light start-up condition, a random number seed is generated based on the unique identifier of the photovoltaic shut-off device; Based on the random number seed, a first random delay value and a second random delay value are generated; The first switch is controlled to turn on after a delay of the first random delay value, and after the first switch is turned on, the second switch is controlled to turn on after a delay of the second random delay value.

6. The photovoltaic shutdown start-up control method according to claim 1, characterized in that, When a switch is turned on, the steps to determine whether the current operation is in a low-light start-up state include: After receiving the switch tube turn-on command, the current input voltage and historical power outage records of the photovoltaic power cut-off device are obtained; If the current input voltage is less than the preset low light voltage threshold, or if the historical power outage records indicate that there are more than a predetermined number of power outage events in the current time period, then the current state is determined to be low light start-up mode. If the current input voltage is greater than or equal to the preset low light voltage threshold, and the historical power outage records indicate that there are no more than a predetermined number of power outage events in the current time period, then the current operation is determined to be in normal startup condition.

7. The photovoltaic shutdown start-up control method according to claim 1, characterized in that, After determining whether the current operation is in a low-light startup condition, the method further includes: If the current operation is in normal startup condition, the first switch and the second switch are directly turned on.

8. A photovoltaic switch start-up control device, characterized in that, A controller applied in a photovoltaic (PV) shutdown device, the PV shutdown device further comprising a first switching transistor and a second switching transistor; the controller is connected to the first switching transistor and the second switching transistor respectively; the first switching transistor and the second switching transistor are respectively used to control the on / off state of two PV module circuits; the device is used to execute the PV shutdown device start-up control method as described in any one of claims 1-7, the device comprising: The judgment module is used to determine whether the current state is a low light start-up condition when a switch tube is turned on. The delayed-on module is used to first randomly delay the on-time of the first switch transistor when the current low-light start-up condition is met, and then randomly delay the on-time of the second switch transistor after the first switch transistor is turned on. The control module is used to control the on / off state of the two switching transistors according to the current input voltage of the photovoltaic switch after the first switching transistor is turned on or after both switching transistors are turned on.

9. An electronic device, characterized in that, It includes a processor and a memory, the memory storing a computer program that can be executed by the processor, the processor being able to execute the computer program to implement the photovoltaic shutdown start-up control method as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the photovoltaic shutdown start-up control method as described in any one of claims 1-7.

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