Distributed turn-off control method and system based on heartbeat signals

Abstract

The invention relates to the field of photovoltaic technology, in particular to a distributed turn-off control method and system based on heartbeat signals. The method comprises the following steps: an inverter issues a periodic heartbeat signal to an optimizer, and after the optimizer receives the heartbeat signal and switches on, a photovoltaic module enters normal power generation work; and the temperature sensing element monitors the working temperature of the photovoltaic module in real time, triggers a multi-stage turn-off response mechanism of the optimizer when monitoring that the working temperature is abnormal so as to actively cut off the heartbeat of the current photovoltaic group string for switching off, and transmits the switching-off state of the optimizer to the inverter. A turn-off decision is issued to a photovoltaic module end, direct monitoring of the working temperature of the photovoltaic module is taken as a trigger condition, an optimizer is driven to actively disconnect the heartbeat of the current photovoltaic string, and the equipment end is endowed with an autonomous decision-making capability, so that intermediate delay in the prior art is avoided, and the response speed to a distributed fault with sudden high temperature is improved; and high-efficiency and accurate system-level turn-off is realized, so that the fire hazard of the photovoltaic system is effectively prevented.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, specifically to a distributed shutdown control method and system based on heartbeat signals. Background Technology

[0002] The series optimizer architecture is a highly efficient grid-connected photovoltaic (PV) system. A series optimizer PV system includes an inverter and several PV strings connected in parallel to the inverter. Each PV string contains several PV modules and an optimizer. Each PV module is connected to an optimizer capable of power optimization, forming a DC bus. The subsequent PV inverter then transfers energy to the grid. One optimizer can be connected to one or more PV modules. The series optimizer architecture decouples the maximum power point tracking (MPPT) of the PV array into the MPPT of each individual PV module. While solving the problems of PV module mismatch and partial shading, it also offers advantages such as low cost, high efficiency, flexible system configuration, and good scalability.

[0003] However, due to the high DC voltage generated by the series-connected photovoltaic (PV) module array, heat can easily accumulate rapidly and cause sudden high temperatures when triggered by adverse internal or external factors such as electrical faults or poor heat dissipation, posing a significant safety hazard. Therefore, there is an urgent need for a shutdown control scheme that can achieve efficient, precise, and system-level shutdown when PV system equipment experiences a sudden high temperature, in order to prevent major safety accidents such as fires and improve the safety of PV systems.

[0004] Currently, some existing technologies rely on the photovoltaic inverter detecting faults (such as DC arcing or grid outages) and actively controlling the discharge circuit to quickly reduce the voltage of the photovoltaic modules, achieving system-level shutdown. Simultaneously, they stop sending heartbeat signals to prevent equipment recovery. However, this approach typically focuses on monitoring electrical faults such as arcing, relying solely on the detection of indirect electrical parameters (such as voltage / current anomalies) at the inverter end. High temperatures may precede electrical faults, and the shutdown trigger is entirely controlled by the photovoltaic inverter (or central controller), initiating shutdown by detecting DC arcing or grid anomalies. The equipment acts only as a passive execution unit, its state changes dependent on the inverter's heartbeat signals and voltage changes. This design cannot respond promptly to sudden high-temperature faults in the photovoltaic modules, leading to delayed or missed shutdowns. In other words, the response delay in existing technologies depends on the inverter's detection speed, especially for distributed sudden high-temperature anomalies, where the response speed is insufficient. Moreover, the heartbeat signal has a single function, which is only used to maintain the connection of photovoltaic module equipment and as an auxiliary means to prevent the equipment from recovering after shutdown. For example, after the inverter stops sending the heartbeat signal, the photovoltaic module equipment enters the standby state, which cannot adapt to complex fault scenarios.

[0005] Another part of the existing technology relies solely on local hardware events to trigger component-level shutdown, meaning the shutdown is isolated and the protection mechanism depends on hardware. Each photovoltaic module independently handles temperature anomalies. When the shutdown device overheats, the fuse blows, physically disconnecting the circuit and ensuring current flow to other photovoltaic modules in the system through a bypass diode. However, this solution requires the temperature to accumulate to the fuse blowing threshold before responding to shutdown. The response time is limited by thermal conductivity, making it unable to meet the immediate shutdown requirements for sudden high temperatures. Furthermore, because the protection mechanism relies on hardware, the thermal fuse needs to be physically replaced after it blows, resulting in rigid control logic that is difficult to handle complex operating conditions. Moreover, when a single photovoltaic module overheats, only that module can be isolated; it cannot notify the inverter or other photovoltaic modules to take action, making it difficult to prevent cascading risks such as fires. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a distributed shutdown control method and system based on heartbeat signals, aiming to rapidly respond to distributed faults caused by sudden high temperatures, achieve efficient and precise system-level shutdown, and effectively prevent fire hazards in photovoltaic systems.

[0007] In a first aspect, this application provides a distributed shutdown control method based on heartbeat signals, applied to a photovoltaic system with a series optimizer structure. Each optimizer is equipped with a temperature sensing element and is communicatively connected to the inverter. The method includes the following steps:

[0008] S1, the inverter sends a periodic heartbeat signal to the optimizer. After the optimizer receives the heartbeat signal and closes the circuit, the photovoltaic module enters normal power generation operation.

[0009] S2, the temperature sensing element monitors the operating temperature of the photovoltaic module in real time. When an abnormal operating temperature is detected, it triggers the multi-level shutdown response mechanism of the optimizer to actively disconnect the heartbeat of the current photovoltaic string to open the gate, and transmits the optimizer's gate opening status to the inverter.

[0010] In some embodiments, S2, when an abnormal operating temperature is detected, the optimizer's multi-level shutdown response mechanism is triggered to actively disconnect the heartbeat of the current photovoltaic string to open the gate, including:

[0011] S211, when the operating temperature is detected to be greater than the first temperature threshold and less than the second temperature threshold for the first time, the optimizer temporarily disconnects the heartbeat of the current photovoltaic string and opens the gate, and the current photovoltaic string stops generating electricity.

[0012] S212, repeat step S2 to continuously monitor the operating temperature of the photovoltaic module. When the operating temperature is detected to gradually decrease to below the third temperature threshold, the optimizer restores the heartbeat of the current photovoltaic string and closes the circuit, and the photovoltaic module resumes normal power generation. The third temperature threshold is less than the first temperature threshold.

[0013] In some embodiments, S2, when an abnormal operating temperature is detected, the optimizer's multi-level shutdown response mechanism is triggered to actively disconnect the heartbeat of the current photovoltaic string to open the gate, including:

[0014] When the operating temperature is detected to be greater than or equal to the second temperature threshold, the optimizer disconnects the heartbeat of the current photovoltaic string to open the gate and transmits the optimizer's open status to the inverter, waiting to be restarted.

[0015] In some embodiments, S2, when an abnormal operating temperature is detected, triggering the optimizer's multi-level shutdown response mechanism to actively disconnect the heartbeat of the current photovoltaic string for gate opening, further includes:

[0016] When the detected operating temperature is greater than or equal to the second temperature threshold, the optimizer continuously monitors the operating temperature of the photovoltaic module and compares the detected operating temperature with the second temperature threshold n times within the diagnostic cycle, where n is a positive integer.

[0017] If any of the comparison results show that the operating temperature is lower than the second temperature threshold, then step S2 is executed again.

[0018] If the results of n consecutive comparisons are all that the operating temperature is greater than or equal to the second temperature threshold, the optimizer disconnects the heartbeat of the current photovoltaic string to open the gate and transmits the optimizer opening status to the inverter, waiting to be restarted.

[0019] In some embodiments, prior to step S1, the method further includes:

[0020] The user defines the heartbeat period for the inverter to send heartbeat signals to each optimizer. When the user defines the heartbeat period, the inverter will actively stop sending heartbeat signals to the corresponding optimizer when the maximum interval threshold is reached. The optimizer will not receive the heartbeat signal and will trigger the disconnection of the heartbeat of the current photovoltaic string to open the gate, and the current photovoltaic string will stop generating electricity.

[0021] In some embodiments, if the custom heartbeat cycle does not exceed the maximum interval threshold, the diagnostic cycle of the optimizer is consistent with the heartbeat cycle of the inverter sending the heartbeat signal to the corresponding optimizer; if the custom heartbeat cycle exceeds the maximum interval threshold, the diagnostic cycle is the maximum interval threshold.

[0022] In some embodiments, the inverter is equipped with a hardware button, which is used by the user to manually enable or disable the sending of heartbeat signals to the optimizer.

[0023] In some embodiments, each optimizer and inverter are connected via HPLC high-speed carrier communication.

[0024] In some embodiments, the optimizer is equipped with a fuse. In step S2, when an abnormal operating temperature is detected, the optimizer's multi-level shutdown response mechanism is triggered to actively disconnect the heartbeat of the current photovoltaic string and open the gate, including:

[0025] When the operating temperature is detected to be greater than or equal to the fourth temperature threshold, the optimizer's fuse blows, the optimizer is passively opened, and the optimizer's open status is transmitted to the inverter, awaiting maintenance. The fourth temperature threshold is greater than the second temperature threshold.

[0026] Secondly, this application provides a distributed shutdown control system based on heartbeat signals, used to execute the aforementioned distributed shutdown control method based on heartbeat signals. The system includes an inverter, a DC bus, and several optimizers. Each optimizer is connected to the inverter via HPLC high-speed carrier communication. The inverter sends periodic heartbeat signals to the optimizers connected to the photovoltaic modules in the photovoltaic system and receives the on / off status transmitted by the optimizers. The inverter has hardware buttons for users to manually enable or disable sending heartbeat signals to the optimizers. The optimizers are used to shut down or connect the circuit between the connected photovoltaic modules and the DC bus through on / off operations, and to optimize the power of the connected photovoltaic modules. Each optimizer contains a temperature sensing element and a fuse.

[0027] The beneficial technical effects of the present invention include at least the following:

[0028] 1. A distributed shutdown control method and system based on heartbeat signals is adopted. By using temperature signals as direct triggers, the heartbeat signal is reconstructed from an existing "connection maintenance tool" into an "active safety controller." Through deep integration of temperature monitoring and the core control logic of the heartbeat signal, a signal-driven distributed intelligent shutdown mechanism led by the device end is creatively invented, realizing a transformation from passive protection to active prevention. Essentially, it breaks the existing central control paradigm, delegating shutdown decisions to the photovoltaic module end. Direct monitoring of the photovoltaic module's operating temperature is used as a trigger condition to actively disconnect the current photovoltaic string's heartbeat, giving the device end (optimizer) autonomous decision-making capabilities. Simultaneously, combined with HPLC communication to maintain system-level coordination, it avoids the indirect detection of electrical parameters by the inverter in existing central control and the intermediate delay of the inverter's central control processing of parameters before issuing commands. Furthermore, because the heartbeat signal is continuous, it further improves the response speed to distributed faults caused by sudden high temperatures, achieving efficient and accurate system-level shutdown, thereby effectively preventing fire hazards in photovoltaic systems.

[0029] 2. Through the design of a multi-level shutdown response mechanism, firstly, an intelligent primary protection closed loop is constructed to specifically handle reversible, non-catastrophic sudden temperature rises (such as short-term overloads or temporarily excessively high ambient temperatures). In this case, fully automated management from fault detection and shutdown to recovery is achieved, significantly reducing operation and maintenance costs and the need for human intervention, avoiding "one-size-fits-all" permanent shutdowns. At the same time, a temperature hysteresis design is introduced to ensure the stability of optimizer state switching and prevent the impact of frequent switching on equipment and the power grid. Secondly, events with operating temperatures greater than or equal to the second temperature threshold are considered more serious faults. Therefore, recovery at this time requires external intervention to restart, effectively preventing the fault from expanding and recurring, reflecting the safety and reliability of the design. Next, the most reliable protection method, hardware fuse blowing, is set as the final level of temperature-triggered shutdown and combined with high-speed HPLC communication to ensure that software responds quickly in most manageable situations, and hardware fuse blowing is only triggered in extreme cases of complete software failure. This ultimately forms a tiered, redundant protection system, progressing from "software-recoverable shutdown" (Level 1) to "software-restartable shutdown" (Level 2) and then to "hardware-fuse shutdown" (Level 3). The software layer provides fast and intelligent primary and secondary protection, while the hardware layer provides absolutely reliable final protection. This combination achieves both the speed and flexibility of the software system and ensures ultimate safety through hardware. Simultaneously, HPLC communication, acting like a neural network, feeds back the status of each stage of this multi-level shutdown response mechanism to the inverter in real time, which then reports the alarm to the cloud platform. By successfully integrating the speed and flexibility of software control with the absolute reliability of hardware protection, it achieves instant detection, rapid decision-making, precise isolation, and coordinated shutdown of sudden high temperatures in photovoltaic modules. This effectively solves the problems of slow response, inaccuracy, and difficulty in coordination found in traditional solutions, providing an efficient, accurate, and reliable system-level shutdown control scheme for preventing photovoltaic system fires.

[0030] 3. The trigger condition for the secondary response was optimized from "instantaneous value exceeding the limit" to "continuous value exceeding the limit," significantly improving the system's stability and intelligence level without sacrificing safety response speed. Specifically, through continuous sampling and confirmation, it is ensured that the shutdown action is based on a continuous high-temperature fault, effectively avoiding false shutdowns caused by instantaneous false alarms from sensors or short-term drastic fluctuations in ambient temperature. This reduces unnecessary downtime, making shutdown decisions more scientific and accurate, and improving the system's power generation availability. Simultaneously, the diagnostic cycle is tied to the heartbeat cycle and has an upper limit (maximum 15 seconds). While preventing false alarms, it still ensures that a genuine continuous fault is diagnosed and shutdown is executed within a few seconds, a response speed far faster than hardware fuse solutions that rely on heat conduction.

[0031] Other features and advantages of the present invention will be disclosed in detail in the following detailed description and accompanying drawings. Attached Figure Description

[0032] The invention will be further described below with reference to the accompanying drawings:

[0033] Figure 1 This is a flowchart of a distributed shutdown control method based on heartbeat signals according to Embodiment 1 of the present invention.

[0034] Figure 2 This is a flowchart illustrating the distributed shutdown control method based on heartbeat signals in Embodiment 1 of the present invention.

[0035] Figure 3 This is a flowchart illustrating the distributed shutdown control method based on heartbeat signals in Embodiment 2 of the present invention.

[0036] Figure 4 This is a schematic diagram of the distributed shutdown control system based on heartbeat signals in Embodiment 3 of the present invention.

[0037] Figure 5 This is a schematic diagram of the distributed shutdown control system based on heartbeat signals in Embodiment 4 of the present invention. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be explained and described below with reference to the accompanying drawings. However, the following embodiments are only preferred embodiments of the present invention and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments in the implementation methods without creative effort are all within the protection scope of the present invention.

[0039] In the following description, terms such as “inner,” “outer,” “upper,” “lower,” “left,” and “right” are used only to indicate orientation or positional relationship for the convenience of describing the embodiments and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0040] Example 1:

[0041] Please see the appendix Figure 1 , Figure 1 A flowchart illustrating a distributed shutdown control method based on heartbeat signals provided in one embodiment of this specification is shown.

[0042] like Figure 1 As shown, the distributed shutdown control method based on heartbeat signals may include at least the following steps:

[0043] S1, the inverter sends a periodic heartbeat signal to the optimizer. After the optimizer receives the heartbeat signal and closes the circuit, the photovoltaic module enters normal power generation operation.

[0044] In existing photovoltaic systems, the heartbeat signal is a periodic communication signal sent by the inverter or CNC to the optimizer / monitoring shutdown device to prove that the equipment (optimizer / monitoring shutdown device) is "online". When the photovoltaic system is working normally, the heartbeat signal is continuously sent, and the equipment keeps the photovoltaic modules conducting and generating electricity.

[0045] Specifically, after the photovoltaic system is powered on each day, the CNC (signal controller) located on or connected to the inverter side begins to operate. In this embodiment, the inverter acts as the sender of the heartbeat signal, periodically sending heartbeat signals to all its subordinate optimizers. Each optimizer continuously listens for signals, and upon receiving a heartbeat signal that conforms to the protocol, its internal processor decodes and verifies it to confirm that the signal source is correct and the content is complete. If the optimizer successfully receives and verifies the heartbeat signal, it means that the photovoltaic system is in a normal state, and the optimizer immediately controls its internal fast switching unit (such as a MOSFET) to conduct, i.e., performs a "closing" operation. At this time, the photovoltaic modules connected to the optimizer are connected to the circuit and begin outputting electrical energy. All optimizers operate in this manner, forming a complete conduction loop for the entire photovoltaic string. The DC power generated by the photovoltaic modules, after power optimization by the optimizer, is delivered to the inverter, converted into AC power, and fed into the grid, allowing the system to enter normal power generation operation. This is a parallel and continuous protection mechanism. While generating electricity normally, the optimizer will monitor the reception of the heartbeat signal in real time. As long as the optimizer can continuously receive the heartbeat signal, it will maintain this closed-circuit power generation state.

[0046] Furthermore, in this embodiment, each optimizer and inverter are connected via HPLC high-speed carrier communication.

[0047] It is understood that this embodiment further employs HPLC (High-Speed ​​Power Line Carrier) communication. Compared with the wireless communication used in the prior art, this embodiment transmits the heartbeat signal through the power line connecting the inverter and the optimizer. The signal is modulated onto the power line using carrier technology, which is unaffected by weather and obstacles. Its high speed helps to ensure safety, has higher reliability, and is more suitable for the harsh environment of photovoltaic power plants.

[0048] Furthermore, in this embodiment, before step S1, the following steps are also included:

[0049] The user defines the heartbeat period for the inverter to send heartbeat signals to each optimizer. When the user defines the heartbeat period, the inverter will actively stop sending heartbeat signals to the corresponding optimizer when the maximum interval threshold is reached. The optimizer will not receive the heartbeat signal and will trigger the disconnection of the heartbeat of the current photovoltaic string to open the gate, and the current photovoltaic string will stop generating electricity.

[0050] Specifically, before the inverter starts working, this embodiment allows users to customize the heartbeat period within a certain range (the default heartbeat period is 3 seconds) according to actual needs (such as system equipment scale and communication load), but sets a safety upper limit (maximum interval threshold of 15 seconds): when the user attempts to set the heartbeat period to more than 15 seconds (such as 20 seconds), the inverter will not wait for the complete set period, but will actively stop sending heartbeat signals to the corresponding optimizer after 15 seconds. This causes the optimizer to not receive a heartbeat signal within the heartbeat period, triggering the disconnection of the heartbeat of the current photovoltaic string to open the gate, and the current photovoltaic string stops generating electricity. That is, the optimizer immediately controls its internal fast switching unit (such as MOSFET) to disconnect, i.e., performs the "opening" operation. At this time, the photovoltaic modules connected to the optimizer cannot be connected to the circuit and stop generating electricity.

[0051] Understandably, a shorter custom heartbeat period results in a faster response, while a longer heartbeat period reduces communication load, thus adapting to different scenarios. The maximum interval threshold set in this embodiment is actually a "misoperation prevention" safety mechanism, preventing users from setting excessively long heartbeats, thereby avoiding increased risks to the photovoltaic system due to heartbeat loss detection delays. Specifically, the longer the heartbeat period, the slower the photovoltaic system's response time to heartbeat loss detection, resulting in higher safety risks (such as shutdown delays during sudden failures). Therefore, this embodiment automatically corrects invalid heartbeat periods set by the user through inverter logic control, forcing shutdown within 15 seconds, ensuring the timely shutdown response of the photovoltaic system, and avoiding the delay risks introduced by excessively long heartbeat periods. This reflects, to some extent, the improvement from the "fixed frequency" of existing technology to the "definable but limited" approach of this embodiment, setting hard safety boundaries through software logic.

[0052] S2, the temperature sensing element monitors the operating temperature of the photovoltaic module in real time. When an abnormal operating temperature is detected, it triggers the multi-level shutdown response mechanism of the optimizer to actively disconnect the heartbeat of the current photovoltaic string to open the gate, and transmits the optimizer's gate opening status to the inverter.

[0053] In photovoltaic systems with a series optimizer structure, if only a single optimizer is turned off, other optimizers in the string may still be in the closed state. However, the abnormal behavior of an optimizer experiencing a sudden high-temperature fault (such as a short circuit) can disrupt the overall electrical balance of the photovoltaic string, leading to string voltage instability or arcing risks. Therefore, this embodiment designs a more conservative and reliable safety strategy. When an abnormal operating temperature is detected, the heartbeat of the entire photovoltaic string is disconnected to open the gate, ensuring string-level shutdown, preventing fault escalation, and only shutting down the heartbeat of the faulty string, isolating strings and localizing the fault shutdown without affecting other normal strings. Simultaneously, HPLC high-speed carrier communication is used to transmit the optimizer's open-gate status to the inverter to ensure rapid coordination and improve overall availability.

[0054] Understandably, the core concept of this embodiment is "signal-driven shutdown," reconstructing the heartbeat signal from an existing "connection maintenance tool" into an "active safety controller." Through the coordination of temperature monitoring and the heartbeat signal, distributed intelligent shutdown of the photovoltaic system is achieved, realizing a shift from passive protection to active prevention. Essentially, it breaks the existing central control paradigm, delegating shutdown decisions to the photovoltaic module end. Direct monitoring of the photovoltaic module's operating temperature serves as a trigger condition, driving the active disconnection of the current photovoltaic string's heartbeat, giving the device end (optimizer) autonomous decision-making capabilities. Simultaneously, it combines HPLC communication to maintain system-level coordination, avoiding the indirect detection of electrical parameters by the inverter in existing central control systems and the intermediate delay in the inverter's central control processing of parameters before issuing commands. Furthermore, because the heartbeat is a continuously existing signal, it further improves the response speed to distributed faults caused by sudden high temperatures, achieving efficient and accurate system-level shutdown, thereby effectively preventing fire hazards in photovoltaic systems.

[0055] Specifically, please refer to the appendix. Figure 2 In this embodiment, S2, when an abnormal operating temperature is detected, the optimizer's multi-level shutdown response mechanism is triggered to actively disconnect the heartbeat of the current photovoltaic string to open the gate, including:

[0056] S211, when the operating temperature is detected to be greater than the first temperature threshold and less than the second temperature threshold for the first time, the optimizer temporarily disconnects the heartbeat of the current photovoltaic string and opens the gate, and the current photovoltaic string stops generating electricity.

[0057] S212, repeat step S2 to continuously monitor the operating temperature of the photovoltaic module. When the operating temperature is detected to gradually decrease to below the third temperature threshold, the optimizer restores the heartbeat of the current photovoltaic string and closes the circuit, and the photovoltaic module resumes normal power generation. The third temperature threshold is less than the first temperature threshold.

[0058] Specifically, when the operating temperature is detected to exceed the first temperature threshold (100°C) for the first time, for example, reaching 105°C, but not yet reaching the second temperature threshold (110°C), the optimizer immediately executes the software shutdown logic, actively disconnecting the heartbeat signal of its photovoltaic string, causing the entire current photovoltaic string to stop generating electricity and the DC voltage to be reduced to a safe range. In the shutdown state, the optimizer's temperature sensing chip does not stop working but continues to monitor the operating temperature, i.e., "repeatedly executing step S2 to continuously monitor the operating temperature of the photovoltaic module." When the monitoring shows that the operating temperature gradually decreases due to the shutdown and cessation of power generation, and drops below the third temperature threshold (95°C), the system determines that the thermal risk has been eliminated. The third temperature threshold (95°C) is lower than the first temperature threshold (100°C). This design establishes a temperature hysteresis range between "shutdown" and "recovery," effectively preventing frequent switching oscillations of the optimizer caused by small temperature fluctuations at the threshold critical points. Once the above recovery conditions are met, the optimizer cancels the shutdown command, automatically closes the circuit breaker to restore normal response to the heartbeat signal, the heartbeat signal path of the corresponding photovoltaic string is re-established, and each photovoltaic module resumes normal power generation. The entire process requires no manual intervention to restart, achieving fully automatic fault healing.

[0059] Understandably, the multi-level shutdown response mechanism in this embodiment constructs an intelligent primary protection closed loop, specifically designed to deal with reversible, non-catastrophic sudden temperature rises (such as short-term overloads or temporarily excessively high ambient temperatures). In this case, it achieves fully automated management from fault detection and shutdown to recovery, significantly reducing operation and maintenance costs and the need for human intervention, avoiding "one-size-fits-all" permanent shutdowns. At the same time, the introduction of temperature hysteresis design ensures the stability of optimizer state switching and prevents frequent switching from impacting equipment and the power grid.

[0060] Specifically, in this embodiment, S2, when an abnormal operating temperature is detected, triggering the optimizer's multi-level shutdown response mechanism to actively disconnect the heartbeat of the current photovoltaic string to open the gate includes:

[0061] When the operating temperature is detected to be greater than or equal to the second temperature threshold, the optimizer disconnects the heartbeat of the current photovoltaic string to open the gate and transmits the optimizer's open status to the inverter, waiting to be restarted.

[0062] For example, when the temperature sensing element detects that the operating temperature of the photovoltaic module is greater than or equal to the second temperature threshold (110°C), the optimizer determines it to be a serious overheating fault and immediately executes the shutdown logic, actively disconnecting the heartbeat signal of its photovoltaic string to open it up. The entire current photovoltaic string stops generating electricity, and the DC voltage drops to a safe range. Simultaneously with the shutdown, the optimizer transmits the "optimizer open (shutdown) status" to the inverter / CNC via the HPLC communication link. The inverter / CNC then reports this to the cloud platform alarm, which maintenance engineers can view immediately. This status signal indicates that the optimizer is offline due to a serious fault and awaits subsequent restart processing. After shutdown, the system enters the "waiting to be restarted" state.

[0063] Understandably, unlike the primary protection loop that automatically recovers at temperatures between 100-110°C, events with operating temperatures ≥110°C are considered more serious faults. Therefore, recovery requires external intervention to restart, effectively preventing the fault from escalating and recurring, reflecting the design's safety and reliability. Restarting is not automatic; it requires a strict prerequisite: the optimizer's operating temperature must have dropped to a safe level (current temperature <110°C). Under this premise, there are two restart recovery methods:

[0064] 1. Manual Intervention Restart (Active Recovery): After receiving a system alarm, the maintenance engineer arrives on-site. First, they must rule out the underlying fault causing the high temperature (such as poor heat dissipation or component damage). Then, confirming that the photovoltaic module temperature is below 110°C, meeting the restart conditions, they manually execute a forced closing command using specialized tools or a specific interface on the equipment. This command simulates or re-issues a heartbeat signal, causing the optimizer to unshut down and the MOSFET to re-close. After successful closing, the photovoltaic string resumes receiving heartbeat signals and restarts normal power generation.

[0065] 2. Natural Cycle Restart (Passive Recovery): Every day after dark, the photovoltaic modules stop generating electricity, and there is no longer any voltage or current input to the system. The optimizer shuts down due to complete power loss. This state is equivalent to a "hard reboot." The next day, after sunrise, sunlight causes the photovoltaic modules to generate electricity again, and the optimizer is powered on and starts up, performing a self-check. After powering on, the optimizer first checks the current temperature of the photovoltaic modules. If the temperature is below 110°C (e.g., after overnight cooling), the optimizer will automatically initialize, resume normal operation, wait for and receive a heartbeat signal, and then close the circuit to generate electricity. If the fault causing the high temperature has not disappeared, and the temperature rises rapidly again after startup, triggering an alarm, the system will execute the shutdown process again, entering a new round of "waiting for restart" state. This forms a fault protection cycle until the root cause is resolved.

[0066] Furthermore, in this embodiment, the optimizer is equipped with a fuse. In S2, when an abnormal operating temperature is detected, the optimizer's multi-level shutdown response mechanism is triggered to actively disconnect the heartbeat of the current photovoltaic string and open the gate, including:

[0067] When the operating temperature is detected to be greater than or equal to the fourth temperature threshold, the optimizer's fuse blows, the optimizer is passively turned on, and the optimizer's on-state is transmitted to the inverter via HPLC, awaiting maintenance. The fourth temperature threshold is greater than the second temperature threshold.

[0068] Specifically, fuse blowing is a purely physical hardware event, independent of the processor, software, or external signals. Even if the optimizer's software system has completely failed due to extreme conditions (such as program crashes or chip damage), the fuse will still blow. Once blown, the photovoltaic module circuit it belongs to is forcibly disconnected, achieving "passive opening." At this time, the optimizer will transmit an "optimizer open status" to the inverter, indicating that it has gone offline due to a hardware failure. This state is irreversible and can only be restored by manually replacing the fuse.

[0069] It is understandable that the multi-level shutdown response mechanism in this embodiment is as follows:

[0070] Level 1 Response (Software Layer): When the temperature is between 100°C and 110°C, a recoverable software shutdown is initiated via a heartbeat signal. The optimizer automatically resumes shutdown when the temperature drops to 95°C.

[0071] Level 2 response (software reinforcement layer): When the temperature exceeds 110°C, a shutdown requiring a restart is triggered (provided the temperature is <110°C).

[0072] Level 3 Response (Hardware Layer): When all the above software protection measures fail for any reason and the temperature continues to rise above 150°C, the fuse will blow as the last line of defense to achieve absolute shutdown.

[0073] To address potential issues, this embodiment employs a clear temperature threshold hierarchy (e.g., 100°C, 110°C, 150°C) for isolation. This ensures rapid software response in most manageable situations, triggering hardware shutdown only in extreme cases of complete software failure. The logic is clear, avoiding redundant operations, thus forming a tiered, redundant protection system from "software recoverable shutdown" (Level 1) to "software restart-required shutdown" (Level 2) and finally to "hardware shutdown" (Level 3). The software layer provides fast, intelligent primary and secondary protection, while the hardware layer provides absolutely reliable final protection. This combination achieves both the speed and flexibility of the software system and ultimate hardware security. Furthermore, HPLC communication, acting like a neural network, feeds back the status of each stage of this multi-level shutdown response mechanism to the inverter in real time, which then reports the alarm to the cloud platform. By setting the most reliable protection method of hardware fuse blowing as the final level of temperature-triggered shutdown and combining it with high-speed HPLC communication, a robust and intelligent safety net is created. This not only solves the concerns about the reliability of pure software systems, but also greatly improves the maintainability of the system through the status reporting function.

[0074] Furthermore, in this embodiment, the inverter is equipped with a hardware button, which is used by the user to manually enable or disable the sending of heartbeat signals to the optimizer.

[0075] The inverter acts as the source of the heartbeat signal, and a hardware button is integrated at this source to directly control whether the heartbeat signal is output. Specifically, in the default state, the inverter continuously sends heartbeat signals to the optimizer according to a custom heartbeat cycle. At this time, the hardware button is in the "on" or "enabled" state, continuously opening the heartbeat signal path. When a user (such as an after-sales engineer) presses this hardware button for maintenance or other needs, a hardware-level event is triggered. This action directly and forcibly cuts off the heartbeat signal transmission path, ensuring that the heartbeat signal stops being sent to the corresponding optimizer. If the optimizer does not detect a heartbeat signal within the heartbeat cycle, it will immediately execute a safety shutdown procedure, disconnecting the internal MOSFET, causing the entire photovoltaic string to stop generating electricity, and the DC voltage to drop to a safe range.

[0076] Understandably, this design elevates the control of the heartbeat signal from a purely "software signal" to a "hardware-controllable resource." When after-sales engineers need to inspect the system, they can directly press the hardware button on-site to forcibly shut off the heartbeat, causing the entire photovoltaic array to quickly drop to a safe voltage without relying on remote commands, thus greatly ensuring personnel safety.

[0077] In summary, traditional solutions (whether it's inverter arc detection or component fuse blowing) are essentially a "post-incident remediation" approach: the former involves a central controller ordering shutdown after an electrical fault occurs, while the latter involves physical fuse blowing after heat accumulates to a hardware damage threshold. Both suffer from significant response delays or lags in action. The core concept of this embodiment is a specific combination of "temperature monitoring + heartbeat signal-driven shutdown," and its fundamental breakthrough lies in:

[0078] 1. Pre-triggered conditions: The temperature signal, the physical quantity that most directly and earliest reflects overheating faults, is used as the primary trigger condition for shutdown. High temperatures are often a precursor or accompanying phenomenon of electrical faults (such as arcing or short circuits). This embodiment directly monitors the operating temperature of the photovoltaic modules, which is equivalent to taking action in the "budding stage" of fire hazards, realizing the transformation from "shutdown after a fault" to "prevention before a hazard occurs."

[0079] 2. Decentralized Decision-Making: The shutdown decision-making power is decentralized from the central inverter to each optimizer. Each optimizer has the ability to make independent judgments and take actions based on local temperature monitoring. This breaks the serial path of "central controller detection - issuing instructions - device execution", eliminates the delay caused by inverter detection, calculation, and communication, and enables the response speed to distributed, sudden high-temperature faults to reach the second level, achieving true "instant response".

[0080] 3. Redefinition and Deep Utilization of the Heartbeat Signal Function: Traditional heartbeat signals are only used to prove that the equipment is online and maintain conduction. This embodiment upgrades it to a virtual "safety enable line". The optimizer's "right" to close and generate electricity is directly dependent on the existence of this signal. When the temperature is abnormal, the optimizer actively disconnects its own response or transmission path to the heartbeat signal, which is equivalent to actively "cutting off" this enable line, causing itself and even the entire string to shut down immediately due to "heartbeat loss".

[0081] Therefore, on the one hand, compared with existing technologies using pure hardware fuses, this embodiment avoids the thermal conduction delay that relies on physical melting, achieving instantaneous shutdown at the "signal level," greatly improving speed. Furthermore, this embodiment is software-configurable and recoverable, avoiding the maintenance burden and rigidity issues associated with replacing blown fuses. On the other hand, compared with existing technologies for centralized inverter control, this embodiment solves the slow response problem caused by the indirectness of electrical parameter detection, communication delays, and central processing unit bottlenecks. Local temperature directly drives local heartbeat control, resulting in the shortest path and fastest speed.

[0082] Example 2:

[0083] This embodiment only applies to comparisons with... Figure 1 and Figure 2The differences between the two embodiments will be described in the following descriptions. The technical concepts of the remaining designs are similar to those of the first embodiment, and will not be repeated here.

[0084] To improve the system's fault tolerance to instantaneous or fluctuating high temperatures, prevent false shutdowns, and ensure a decisive response to real, sustained high-temperature faults, please refer to the appendix. Figure 3 In this embodiment, S2, when an abnormal operating temperature is detected, triggering the optimizer's multi-level shutdown response mechanism to actively disconnect the heartbeat of the current photovoltaic string for gate opening, further includes:

[0085] When the operating temperature is detected to be greater than or equal to the second temperature threshold, the optimizer continuously monitors the operating temperature of the photovoltaic module and compares the detected operating temperature with the second temperature threshold n times during the diagnostic cycle, where n is a positive integer (e.g., n=10).

[0086] If any of the comparison results show that the operating temperature is lower than the second temperature threshold, then step S2 is executed again.

[0087] If the results of n consecutive comparisons are all that the operating temperature is greater than or equal to the second temperature threshold, the optimizer disconnects the heartbeat of the current photovoltaic string to open the gate and transmits the optimizer opening status to the inverter, waiting to be restarted.

[0088] Understandably, when the temperature sensing element detects an abnormal operating temperature of the photovoltaic module, the optimizer processor initiates a corresponding multi-level shutdown response mechanism. The improvement in this embodiment is mainly reflected in the triggering logic of the second-level response (severe overheating, operating temperature greater than or equal to a second temperature threshold, such as 110°C). When the operating temperature is greater than or equal to the second temperature threshold, the optimizer initiates a "diagnostic cycle," and within this cycle, performs continuous and multiple confirmation diagnoses. Diagnostic judgment:

[0089] Scenario 1 (Diagnosis Failed, Possibly Due to Transient Interference): If, in any of the n consecutive comparisons, the operating temperature is lower than the second temperature threshold, the optimizer determines that this overheating may be due to transient fluctuations or sensor interference, and does not meet the conditions for sustained severe overheating. The optimizer will terminate the current diagnostic process and re-execute step S2, i.e., exit the secondary response diagnostic state and resume continuous real-time temperature monitoring. If the temperature subsequently rises back to the second temperature threshold, a new diagnostic cycle will be restarted.

[0090] Scenario 2 (Diagnosis Passed, Confirmed as Continuous Fault): If the operating temperature is greater than or equal to the second temperature threshold in every n consecutive comparisons, the optimizer confirms that the photovoltaic module is in a continuous and genuine severe overheating state and immediately executes a shutdown operation. The optimizer actively disconnects the heartbeat of its photovoltaic string (disconnects the heartbeat signal path or makes itself unresponsive to the heartbeat signal), causing the entire current photovoltaic string to stop generating electricity due to "heartbeat loss," achieving rapid power-off. Simultaneously, the optimizer immediately sends an "optimizer open status" signal to the inverter via the HPLC communication link. The inverter uploads this fault status to the monitoring platform, triggering an alarm. Afterward, the optimizer enters a "waiting to be restarted" locked state.

[0091] Specifically, in this embodiment, if the customized heartbeat cycle does not exceed the maximum interval threshold (system safety limit, such as 15 seconds), the optimizer's diagnostic cycle is consistent with the heartbeat cycle of the inverter sending heartbeat signals to the corresponding optimizer (e.g., both are 3 seconds), thus ensuring that the diagnostic speed is synchronized with the normal communication rhythm of the system. If the customized heartbeat cycle exceeds the maximum interval threshold (e.g., the user sets it to 20 seconds), the diagnostic cycle is the maximum interval threshold (15 seconds), thus ensuring that even if the heartbeat cycle is set too long, the diagnostic confirmation of a severe overheating fault will not exceed the safe time limit of 15 seconds.

[0092] Understandably, this embodiment optimizes the triggering condition for the secondary response from "instantaneous value exceeding the limit" to "continuous value exceeding the limit," significantly improving the system's stability and intelligence level without sacrificing safety response speed. Specifically, by continuously sampling and confirming, it ensures that the shutdown action is based on a continuous high-temperature fault, effectively avoiding false shutdowns caused by instantaneous false alarms from sensors or short-term drastic fluctuations in ambient temperature, reducing unnecessary downtime, making shutdown decisions more scientific and accurate, and improving the system's power generation availability. Simultaneously, the diagnostic cycle is bound to the heartbeat cycle and has an upper limit (maximum 15 seconds), preventing false triggering while still ensuring that a genuine continuous fault is diagnosed and shutdown is executed within a few seconds, a response speed far faster than hardware fuse solutions that rely on heat conduction.

[0093] Example 3:

[0094] Please see the appendix Figure 4 , Figure 4 This is a schematic diagram of a distributed shutdown control system based on heartbeat signals, provided as an embodiment of this specification.

[0095] like Figure 4As shown, the distributed shutdown control system based on heartbeat signals can include at least an inverter, a DC bus, and several optimizers. Each optimizer is connected to the inverter via HPLC high-speed carrier communication. The inverter sends periodic heartbeat signals to the optimizers connected to the photovoltaic modules in the photovoltaic system and receives the opening status transmitted by the optimizers. The inverter is equipped with hardware buttons for users to manually turn on or off sending heartbeat signals to the optimizers. The optimizers are used to turn off or connect the circuit between the connected photovoltaic modules and the DC bus through opening or closing operations, and to optimize the power of the connected photovoltaic modules. The optimizers are equipped with temperature sensing elements and fuses (not shown in the figure).

[0096] The positive terminals of each cascaded optimizer are connected to the corresponding positive terminals of the inverter's DC interface via the positive terminals of the DC bus; the negative terminals of each cascaded optimizer are connected to the corresponding negative terminals of the inverter's DC interface via the negative terminals of the DC bus.

[0097] Understandable, Figure 4 This invention describes a structure where one optimizer is connected to one photovoltaic module, and multiple photovoltaic strings are connected to the inverter through the optimizer. Alternatively, one optimizer can also be connected to two photovoltaic modules. Other specific structures are not detailed here but are all within the scope of this application.

[0098] It is understood that the technical concept of the distributed shutdown control system based on heartbeat signals provided in this embodiment is similar to the technical concept of the aforementioned distributed shutdown control method based on heartbeat signals, and will not be repeated here.

[0099] Example 4:

[0100] Please see the appendix Figure 5 , Figure 5 This is a schematic diagram of a distributed shutdown control system based on heartbeat signals, provided as an embodiment of this specification.

[0101] like Figure 5 As shown, the distributed shutdown control system based on heartbeat signals can include at least an inverter, a CNC, a DC bus, and several optimizers. The inverter and each optimizer are connected to the CNC via HPLC high-speed carrier communication. The CNC is used to send periodic heartbeat signals to the optimizers connected to the photovoltaic modules in the photovoltaic system and to receive the opening status transmitted by the optimizers. The CNC is equipped with hardware buttons for users to manually start or stop sending heartbeat signals to the optimizers. The optimizers are used to shut down or connect the circuit between the connected photovoltaic modules and the DC bus through opening or closing operations, and to optimize the power of the connected photovoltaic modules. The optimizers are equipped with temperature sensing elements and fuses.

[0102] It is understandable that, compared to the system structure in Embodiment 3 that integrates the inverter with the CNC controller, the system structure in this embodiment that uses the inverter and CNC controller to be installed independently is suitable for larger or more complex photovoltaic systems.

[0103] In this embodiment, the CNC controller is installed at the DC terminal of the inverter. A wire harness with a magnetic ring is fitted onto the DC terminal of the inverter to sense the current transmitted from the optimizer to the inverter. Furthermore, the CNC controller, hardware buttons, and magnetic ring can all be integrated into a control box and connected to the DC terminal of the inverter; this will not be elaborated further in this embodiment.

[0104] The above description is merely a preferred embodiment disclosed in this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of protection involved in this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-disclosed concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this disclosure.

[0105] Furthermore, while the operations are described in a specific order, this should not be construed as requiring these operations to be performed in the specific order shown or in a sequential order. In certain environments, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the above discussion, these should not be construed as limiting the scope of this disclosure. Certain features described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

Claims

1. A distributed turn-off control method based on heartbeat signals, applied to a photovoltaic system with a series optimizer structure, characterized in that, The optimizer is equipped with a temperature sensing element, and each optimizer is communicatively connected to the inverter. The method includes the following steps: S1, the inverter sends a periodic heartbeat signal to the optimizer. After the optimizer receives the heartbeat signal and closes the circuit, the photovoltaic module enters normal power generation operation. S2, the temperature sensing element monitors the operating temperature of the photovoltaic module in real time. When an abnormal operating temperature is detected, it triggers the multi-level shutdown response mechanism of the optimizer to actively disconnect the heartbeat of the current photovoltaic string to open the gate, and transmits the optimizer's gate opening status to the inverter.

2. The distributed shutdown control method based on heartbeat signals as described in claim 1, characterized in that, S2, when an abnormal operating temperature is detected, the optimizer's multi-level shutdown response mechanism is triggered to actively disconnect the heartbeat of the current photovoltaic string to open the gate, including: S211, when the operating temperature is detected to be greater than the first temperature threshold and less than the second temperature threshold for the first time, the optimizer temporarily disconnects the heartbeat of the current photovoltaic string and opens the gate, and the current photovoltaic string stops generating electricity. S212, repeat step S2 to continuously monitor the operating temperature of the photovoltaic module. When the operating temperature is detected to gradually decrease to below the third temperature threshold, the optimizer restores the heartbeat of the current photovoltaic string and closes the circuit, and the photovoltaic module resumes normal power generation. The third temperature threshold is less than the first temperature threshold.

3. The distributed shutdown control method based on heartbeat signals as described in claim 1, characterized in that, S2, when an abnormal operating temperature is detected, the optimizer's multi-level shutdown response mechanism is triggered to actively disconnect the heartbeat of the current photovoltaic string to open the gate, including: When the operating temperature is detected to be greater than or equal to the second temperature threshold, the optimizer disconnects the heartbeat of the current photovoltaic string to open the gate and transmits the optimizer's open status to the inverter, waiting to be restarted.

4. The distributed shutdown control method based on heartbeat signals as described in claim 3, characterized in that, S2, when an abnormal operating temperature is detected, triggers the optimizer's multi-level shutdown response mechanism to actively disconnect the heartbeat of the current photovoltaic string to open the gate, and also includes: When the detected operating temperature is greater than or equal to the second temperature threshold, the optimizer continuously monitors the operating temperature of the photovoltaic module and compares the detected operating temperature with the second temperature threshold n times within the diagnostic cycle, where n is a positive integer. If any of the comparison results show that the operating temperature is lower than the second temperature threshold, then step S2 is executed again. If the results of n consecutive comparisons are all that the operating temperature is greater than or equal to the second temperature threshold, the optimizer disconnects the heartbeat of the current photovoltaic string to open the gate and transmits the optimizer opening status to the inverter, waiting to be restarted.

5. The distributed shutdown control method based on heartbeat signals as described in claim 4, characterized in that, Before step S1, the following is also included: The user defines the heartbeat period for the inverter to send heartbeat signals to each optimizer. When the user defines the heartbeat period, the inverter will actively stop sending heartbeat signals to the corresponding optimizer when the maximum interval threshold is reached. The optimizer will not receive the heartbeat signal and will trigger the disconnection of the heartbeat of the current photovoltaic string to open the gate, and the current photovoltaic string will stop generating electricity.

6. The distributed shutdown control method based on heartbeat signals as described in claim 5, characterized in that, If the custom heartbeat cycle does not exceed the maximum interval threshold, the optimizer's diagnostic cycle is consistent with the heartbeat cycle of the inverter sending the heartbeat signal to the corresponding optimizer. If the custom heartbeat cycle exceeds the maximum interval threshold, the diagnostic cycle is the maximum interval threshold.

7. The distributed shutdown control method based on heartbeat signals as described in claim 1, characterized in that, The inverter is equipped with a hardware button, which is used by the user to manually enable or disable the sending of heartbeat signals to the optimizer.

8. The distributed shutdown control method based on heartbeat signals as described in claim 1, characterized in that, Each optimizer and inverter is connected via HPLC high-speed carrier communication.

9. The distributed shutdown control method based on heartbeat signals as described in claim 1, characterized in that, The optimizer has an internal fuse. When an abnormal operating temperature is detected in S2, the optimizer's multi-level shutdown response mechanism is triggered to actively disconnect the heartbeat of the current photovoltaic string and open the gate, including: When the operating temperature is detected to be greater than or equal to the fourth temperature threshold, the optimizer's fuse blows, the optimizer is passively opened, and the optimizer's open status is transmitted to the inverter, awaiting maintenance. The fourth temperature threshold is greater than the second temperature threshold.

10. A distributed shutdown control system based on heartbeat signals, used to execute the distributed shutdown control method based on heartbeat signals as described in any one of claims 1 to 9, characterized in that, It includes an inverter, a DC bus, and several optimizers. Each optimizer is connected to the inverter via HPLC high-speed carrier communication. The inverter sends periodic heartbeat signals to the optimizers connected to the photovoltaic modules in the photovoltaic system and receives the opening and closing status transmitted by the optimizers. The inverter is equipped with hardware buttons for users to manually turn on or off the sending of heartbeat signals to the optimizers. The optimizers are used to turn off or connect the circuit between the connected photovoltaic modules and the DC bus through opening or closing operations, and are used to optimize the power of the connected photovoltaic modules. The optimizers are equipped with temperature sensing elements and fuses.

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