Transient overvoltage protection device with active isolation and reconfiguration function

Abstract

The application relates to the technical field of circuit protection, in particular to a transient overvoltage protection device with active isolation and reconstruction functions, and discloses a system named a transient overvoltage protection device with active isolation and reconstruction functions, which aims to solve the problems of single-point failure and protection interruption caused by performance degradation of metal oxide varistors. The device comprises a main / auxiliary discharge path, a state sensing module and a central cooperative controller; by monitoring the leakage current, temperature and clamping voltage in real time, the controller actively turns off the main path before the element deteriorates and switches to the standby path in milliseconds, so that the reconstruction is realized without disturbance. The scheme ensures that the protection function is continuously effective, and significantly improves the system resilience and power supply safety.

Description

Technical Field

[0001] This invention relates to the field of circuit protection technology, and more specifically, to a transient overvoltage protection device with active isolation and reconfiguration functions. Background Technology

[0002] Against the backdrop of the rapid evolution of modern industrial automation and digital infrastructure, smart grids, high-end manufacturing production lines, and industrial IoT systems are placing increasingly stringent demands on power supply continuity and equipment safety. These systems are commonly deployed in environments with complex and variable electromagnetic conditions, frequently subjected to transient overvoltage surges caused by lightning strikes, switching operations, or sudden load changes. Although these surge events are extremely short-lived, their peak voltages can reach thousands of volts or even higher, easily breaking down the insulation barriers of sensitive electronic components and causing permanent damage to core equipment such as communication modules, edge computing gateways, and precision sensors. This not only leads to production interruptions and data loss but also incurs high maintenance costs and safety risks. Therefore, constructing efficient, reliable, and adaptive transient overvoltage protection mechanisms has become a key technological aspect in ensuring the resilience and availability of new industrial infrastructure.

[0003] To address the aforementioned needs, traditional transient overvoltage protection solutions have long relied on passive discharge structures with metal oxide varistors as the core component. These devices, due to their nonlinear volt-ampere characteristics, exhibit a high-resistivity state under normal operating voltages, but rapidly transition to a low-resistivity state upon encountering an overvoltage, diverting surge energy to ground and thus clamping the voltage level at the protected port. In a specific historical period, this approach effectively alleviated surge protection problems in basic industrial scenarios due to its simple structure, low cost, and relatively faster response speed compared to earlier devices such as gas discharge tubes or avalanche diodes. Its typical implementation usually involves directly connecting the varistor in parallel between the power input and ground, forming a permanent discharge path that automatically responds to overvoltage events without external control.

[0004] However, as industrial systems continue to evolve towards higher integration, higher reliability, and intelligent operation and maintenance, the inherent structural defects of the aforementioned traditional protection architecture at the principle level are gradually becoming apparent, giving rise to a series of deep-seated technical contradictions in actual operation. Specifically, after repeated surge impacts, the internal grain boundary structure of metal oxide varistors undergoes irreversible degradation, manifested as increased leakage current, clamping voltage drift, and even an increased risk of thermal runaway. This degradation process is highly insidious—the device often maintains basic conduction function before failure, making it difficult for the system to accurately assess its remaining lifespan and current protection effectiveness. More importantly, because varistors in traditional solutions are always hard-connected to the main circuit, once their performance degrades to a critical point, they not only fail to effectively dissipate energy in subsequent surge events but may also become a source of failure due to their own impedance abnormalities, causing short circuits, fires, or even cascading damage. Correspondingly, this "operating with defects" state directly leads to a significant single-point failure risk for the entire protection system. Based on this, the existing architecture lacks the ability to perceive and dynamically intervene in the health status of protection units in real time. It cannot proactively isolate devices from the circuit before they fail, nor can it seamlessly switch to backup protection paths after isolation, resulting in a complete interruption of protection functions. The reason for this is that traditional designs treat protection functions as static, one-time configured hardware attributes, rather than dynamic safety services that can be monitored, decided upon, and reconfigured. This conceptual limitation makes it difficult to adapt to the dual requirements of modern industrial systems for "predictive maintenance" and "fault resilience".

[0005] Furthermore, the aforementioned contradictions are amplified dramatically in scenarios requiring high availability. For example, in unattended smart substations or continuously operating smart manufacturing units, equipment damage caused by a single latent failure of a protection device can lead to downtime losses of several hours or even days, with economic costs far exceeding the cost of the protection device itself. In addition, as power supply topologies evolve towards higher frequencies and smaller sizes, systems place higher demands on the response time, energy absorption accuracy, and thermal management capabilities of protection devices. The inherent response delay of traditional varistors (while nanosecond-level response is fast, it is still insufficient for some high-speed digital interfaces) and their non-ideal clamping characteristics also constrain the improvement of overall protection performance at the microscopic level. Thus, existing technologies exhibit an inherent tension that is difficult to reconcile between "protection effectiveness," "state awareness," and "system robustness": pursuing high discharge capability necessitates accepting the uncertainty brought about by device aging; attempting to improve reliability through redundant design inevitably leads to resource waste and complex control logic due to the lack of intelligent switching mechanisms.

[0006] Therefore, how to construct a transient overvoltage protection device that combines real-time status awareness, active fault isolation, and seamless functional reconfiguration capabilities, enabling it to accurately identify and decisively disconnect core protection components before their performance degrades to a dangerous threshold, and simultaneously activate alternative pathways to maintain continuous protection, thereby fundamentally eliminating the risk of single-point failure and achieving full life-cycle controllability of protection functions, has become a key challenge and an urgent technical problem for those skilled in the art. Summary of the Invention

[0007] This invention provides a transient overvoltage protection device with active isolation and reconfiguration functions, aiming to solve the core problems in existing technologies, such as the risk of single-point failure, unsustainable protection functions, and insufficient system toughness caused by the performance degradation of metal oxide varistors. To achieve the above-mentioned objectives, this invention proposes a system-level protection architecture integrating state awareness, active isolation, and dynamic reconfiguration. Through hardware cascaded control logic and multi-path redundancy design, it ensures a smooth switching before the main discharge element deteriorates, thereby maintaining continuous protection for the protected equipment.

[0008] The transient overvoltage protection device includes a main discharge path, an auxiliary discharge path, a status sensing module, a central coordinating controller, and an electrical connection structure between the power input terminal and the ground bus. The main discharge path includes at least one metal oxide varistor. The input terminal of the metal oxide varistor is connected to the power input terminal via a first field-effect transistor switch, and its output terminal is directly connected to the ground bus. The first field-effect transistor switch is an N-channel enhancement-mode power MOSFET, with its source electrically connected to the input terminal of the metal oxide varistor, its drain electrically connected to the power input terminal, and its gate controlled by a drive signal output by the central coordinating controller.

[0009] The auxiliary discharge path includes a parallel branch consisting of a second field-effect transistor switch and a backup metal oxide varistor, or an independent discharge path consisting of a gas discharge tube and a current-limiting inductor connected in series. The drain of the second field-effect transistor switch is connected to the power input terminal, and the source is connected to one end of the backup metal oxide varistor, the other end of which is connected to the ground busbar. If a gas discharge tube scheme is used, one end of the gas discharge tube is connected to the power input terminal, and the other end is connected to the ground busbar via the current-limiting inductor. The trigger end of the gas discharge tube is connected to a high-voltage pulse excitation circuit controlled by a central coordinating controller.

[0010] The status sensing module includes a leakage current sampling unit, a temperature sensing unit, and a clamping voltage monitoring unit. The leakage current sampling unit consists of a high-precision sampling resistor and a differential amplifier. The sampling resistor is connected in series in the grounding loop of the metal oxide varistor. The input terminal of the differential amplifier is connected across the two ends of the sampling resistor, and the output terminal is connected to the analog signal input interface of the central coordinating controller. The temperature sensing unit is a thermistor or digital temperature sensor mounted on the surface of the metal oxide varistor. Its signal output terminal is connected to the temperature acquisition channel of the central coordinating controller. The clamping voltage monitoring unit consists of a high-speed comparator and a reference voltage source. The positive input terminal of the high-speed comparator is connected to the input terminal of the metal oxide varistor, the negative input terminal is connected to the reference voltage source corresponding to a preset threshold, and the output terminal is connected to the digital interrupt pin of the central coordinating controller.

[0011] The central coordinating controller is an embedded microcontroller based on the ARM Cortex-M series core, which integrates an analog-to-digital converter, timers, general-purpose input / output ports, and non-volatile memory. The central coordinating controller periodically reads the output signals of the leakage current sampling unit and the temperature sensing unit through the analog-to-digital converter, and calculates the comprehensive health index of the metal oxide varistor in real time by combining the state changes of the clamping voltage monitoring unit. The health index is determined according to the failure criterion model pre-stored in the non-volatile memory. The failure criterion model defines the weighted logical relationship between the leakage current amplitude, the temperature rise rate, and the clamping voltage offset. When the comprehensive health index is lower than the preset failure threshold, the central coordinating controller immediately executes the protection reconfiguration process.

[0012] During normal operation, the central coordinating controller outputs a high-level drive signal to the gate of the first field-effect transistor switch, putting it in a fully conducting state. The main discharge path presents a low-impedance connection, and the metal oxide varistor normally undertakes the task of transient overvoltage discharge. At the same time, the central coordinating controller outputs a low-level signal to the second field-effect transistor switch, keeping it in a turned-off state, and the backup metal oxide varistor branch is in an electrically isolated state. If a gas discharge tube scheme is used, the high-voltage pulse excitation circuit is in standby mode, and the gas discharge tube maintains a high-impedance state.

[0013] When the central coordinating controller determines that the performance of the metal oxide varistor in the main discharge path has degraded to a preset failure threshold, it immediately performs the following sequence of operations: First, it sets the gate drive signal of the first field-effect transistor switch to a low level, forcibly turning off the switch and cutting off the electrical connection between the metal oxide varistor and the power input terminal, thereby achieving active isolation of the degraded component; Second, after confirming that the first field-effect transistor switch has been completely turned off, it synchronously starts the activation mechanism of the auxiliary discharge path; If the auxiliary discharge path adopts a backup metal oxide varistor structure, the central coordinating controller outputs a high-level drive signal to the second field-effect transistor switch to turn it on, thereby connecting the backup metal oxide varistor to the main circuit; If the auxiliary discharge path adopts a gas discharge tube structure, the central coordinating controller triggers a high-voltage pulse excitation circuit, applying a momentary high-voltage pulse sufficient to induce glow discharge across the gas discharge tube, causing it to quickly switch to a low-resistance conduction state and establish a new surge discharge path.

[0014] During the isolation and reconfiguration operations, the central coordinating controller strictly adheres to the timing constraint mechanism to ensure that there is no protection window between the disconnection of the main discharge path and the closure of the auxiliary discharge path. Specifically, the turn-off action of the first field-effect transistor switch is precisely controlled by a hardware timer, with a turn-off delay time not exceeding ten nanoseconds. The activation command for the auxiliary discharge path is issued within a time window of no more than fifty nanoseconds, and the turn-on rise time of the second field-effect transistor switch or the breakdown response time of the gas discharge tube are both limited to within one hundred nanoseconds, thereby ensuring that at least one effective discharge path is ready when any transient overvoltage event occurs.

[0015] Furthermore, the transient overvoltage protection device also includes a communication interface module, which is an RS-485 bus transceiver or an Ethernet physical layer chip. Its data port is connected to the serial communication peripheral of the central coordinating controller to upload the real-time health status of the metal oxide varistor, historical surge event records, and current working path identification information to the upper-level monitoring system. The communication interface module supports Modbus RTU or IEC 61850-9-2LE protocol to achieve seamless integration with industrial automation systems.

[0016] In a preferred embodiment of the present invention, the main discharge path and the auxiliary discharge path adopt a symmetrical layout structure, and their parasitic inductance and distributed capacitance parameters are kept highly consistent to eliminate the reflection effect of impedance change caused by path switching on high-frequency surge waveform; the metal oxide varistor and the field-effect transistor switch are both mounted on the same heat dissipation substrate, which is tightly attached to the metal shell by thermal grease to form an efficient heat conduction path; the grounding bus adopts a low-impedance copper bus structure with a cross-sectional area of ​​not less than 25 square millimeters to ensure that the voltage drop during the high current discharge process is minimized.

[0017] During each system power-on initialization phase, the central coordinating controller executes a self-test procedure to verify the functional integrity of the first MOSFET switch, the second MOSFET switch, and the status sensing module. If any critical component is detected to have an open circuit, short circuit, or abnormal signal, all output drive signals are immediately locked, and a fault code is reported through the communication interface module to prevent operation with defects.

[0018] In addition, the device described in this invention also has a surge event recording function. After the central coordinating controller detects a valid interrupt signal output by the clamping voltage monitoring unit each time, it automatically records the time of the event, duration, peak leakage current and corresponding temperature value, and writes the data into the circular buffer of the non-volatile storage unit. It can store the complete parameter set of the most recent one thousand surge events for subsequent fault analysis and life prediction.

[0019] In summary, this invention, by introducing a state-aware driven active isolation mechanism and a millisecond-level response dynamic reconfiguration strategy, completely changes the static and passive working mode of traditional transient overvoltage protection devices. It not only enables precise intervention in the early stages of performance degradation of core protection components, preventing latent failures from evolving into catastrophic faults, but also ensures the continuous effectiveness of protection functions throughout the entire lifecycle through seamless switching of hardware-level redundant paths. The system architecture of this device has high engineering feasibility; all control logic is executed by an embedded controller without external intervention, making it suitable for applications with stringent power supply safety requirements, such as smart grids, industrial IoT nodes, edge computing servers, and high-reliability manufacturing equipment. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of a transient overvoltage protection device with active isolation and reconfiguration functions according to the present invention.

[0021] Figure 2 This is a flowchart illustrating the switching timing and control logic between the main discharge path and the auxiliary discharge path in this invention. Detailed Implementation

[0022] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0023] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly or indirectly attached to that other component. When a component is referred to as being "connected to" another component, it can be directly or indirectly connected to that other component.

[0024] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0026] This invention provides a transient overvoltage protection device with active isolation and reconfiguration functions, the overall structure of which is as follows: Figure 1 As shown, the device includes a main discharge path, an auxiliary discharge path, a status sensing module, a central coordination controller, and the electrical connection structure between the power input terminal and the grounding busbar. This device achieves continuous and reliable protection against transient overvoltage events by integrating status sensing, active isolation, and dynamic reconfiguration mechanisms.

[0027] The main discharge path consists of at least one metal-oxide-semiconductor (MOSFET). The input of this MOSFET is connected to the power input terminal via a first field-effect transistor (FET) switch, and its output is directly connected to the ground bus. The first FET switch is an N-channel enhancement-mode power MOSFET, with its source electrically connected to the input of the MOSFET, its drain electrically connected to the power input terminal, and its gate controlled by a drive signal output from the central co-controller. During normal operation, the central co-controller applies a high-level drive signal to the gate of the first FET switch, putting it in a fully conducting state, thereby connecting the MOSFET to the main circuit to handle transient overvoltage discharge.

[0028] The auxiliary discharge path can adopt two structural forms: one is a parallel branch consisting of a second field-effect transistor switch and a backup metal-oxide varistor; the other is an independent discharge path consisting of a gas discharge tube and a current-limiting inductor connected in series. In the first structure, the drain of the second field-effect transistor switch is connected to the power input terminal, and the source is connected to one end of the backup metal-oxide varistor, the other end of which is connected to the ground bus. In the second structure, one end of the gas discharge tube is connected to the power input terminal, and the other end is connected to the ground bus via the current-limiting inductor. The trigger end of the gas discharge tube is connected to a high-voltage pulse excitation circuit controlled by the central coordinating controller. Under normal conditions, the central coordinating controller outputs a low-level signal to the second field-effect transistor switch to keep it off, and the backup metal-oxide varistor branch is in an electrically isolated state. If the gas discharge tube scheme is used, the high-voltage pulse excitation circuit is in standby mode, and the gas discharge tube maintains a high-impedance state.

[0029] The status awareness module includes a leakage current sampling unit, a temperature sensing unit, and a clamping voltage monitoring unit. The leakage current sampling unit consists of a high-precision sampling resistor and a differential amplifier. The sampling resistor is connected in series in the grounding loop of the metal oxide varistor. The input of the differential amplifier is connected across the sampling resistor, and its output is connected to the analog signal input interface of the central coordinating controller. The temperature sensing unit is a thermistor or digital temperature sensor mounted on the surface of the metal oxide varistor. Its signal output is connected to the temperature acquisition channel of the central coordinating controller. The clamping voltage monitoring unit consists of a high-speed comparator and a reference voltage source. The positive input of the high-speed comparator is connected to the input of the metal oxide varistor, the negative input is connected to the reference voltage source corresponding to a preset threshold, and the output is connected to the digital interrupt pin of the central coordinating controller. When the voltage across the metal oxide varistor exceeds the preset clamping threshold, the high-speed comparator outputs a switching signal, triggering the interrupt service routine of the central coordinating controller.

[0030] The central coordinating controller is an embedded microcontroller based on the ARM Cortex-M series core, integrating an analog-to-digital converter, timers, general-purpose input / output ports, and non-volatile memory. The central coordinating controller periodically reads the output signals of the leakage current sampling unit and the temperature sensing unit through the analog-to-digital converter, and combines this with the state changes of the clamping voltage monitoring unit to calculate the comprehensive health index of the metal oxide varistor in real time. This health index is determined based on a failure criterion model pre-stored in the non-volatile memory, which defines the weighted logical relationship between leakage current amplitude, temperature rise rate, and clamping voltage offset. Specifically, the comprehensive health index H can be expressed as:

[0031] H=w1×f(I leak )+w2×f(ΔT / Δt)+w3×f(ΔVclamp Among them, I leak The current leakage current is given, ΔT / Δt is the temperature rise rate per unit time, and ΔV is the current leakage current value. clamp The clamping voltage is the offset relative to the initial nominal value. w1, w2, and w3 are normalized weighting coefficients that satisfy w1 + w2 + w3 = 1. The function f(.) is a monotonically decreasing mapping used to convert the physical quantity into a health score. When the comprehensive health index H is lower than the preset failure threshold Hth, the central coordinating controller immediately initiates the protection reconfiguration process.

[0032] During the reconfiguration process, the central coordinating controller first sets the gate drive signal of the first MOSFET switch to a low level, forcibly turning off the switch and severing the electrical connection between the metal oxide varistor and the power input terminal, thus achieving active isolation of the degraded component. This turn-off action is precisely controlled by a hardware timer, with a turn-off delay time not exceeding ten nanoseconds. After confirming that the first MOSFET switch is completely turned off, the central coordinating controller synchronously activates the auxiliary discharge path activation mechanism. If the auxiliary discharge path uses a backup metal oxide varistor structure, the central coordinating controller outputs a high-level drive signal to the second MOSFET switch, turning it on and connecting the backup metal oxide varistor to the main circuit; the rise time of the second MOSFET switch is limited to within 100 nanoseconds. If the auxiliary discharge path uses a gas discharge tube structure, the central coordinating controller triggers a high-voltage pulse excitation circuit, applying a momentary high-voltage pulse sufficient to induce glow discharge across the gas discharge tube, causing it to quickly switch to a low-resistance conduction state; the breakdown response time of the gas discharge tube is also controlled to within 100 nanoseconds. The above operations ensure that there is no protection gap between the disconnection of the main discharge path and the closure of the auxiliary discharge path, and that at least one effective discharge path is ready when any transient overvoltage event occurs.

[0033] In a preferred embodiment of the present invention, the main discharge path and the auxiliary discharge path adopt a symmetrical layout structure, and their parasitic inductance and distributed capacitance parameters are highly consistent. Specifically, the trace length, width, and stack-up structure from the power input terminal to each discharge element are strictly matched to eliminate the reflection effect of impedance sudden changes caused by path switching on the high-frequency surge waveform. The metal oxide varistor and the field-effect transistor switch are both mounted on the same heat dissipation substrate, which is made of high thermal conductivity aluminum-based copper-clad laminate with a thickness of not less than 1.5 mm and covered with an insulating ceramic coating. The heat dissipation substrate is tightly attached to the metal shell with thermal grease to form an efficient heat conduction path, ensuring that heat can be rapidly dissipated during high current discharge. The grounding bus adopts a low-impedance copper bus structure with a cross-sectional area of ​​not less than 25 square millimeters and a tin-plated surface to reduce contact resistance, ensuring that the voltage drop of the grounding loop does not exceed the system's allowable residual voltage margin under the maximum discharge current condition.

[0034] The transient overvoltage protection device also includes a communication interface module, which is an RS-485 bus transceiver or an Ethernet physical layer chip. Its data port is connected to the serial communication peripheral of the central coordinating controller. The communication interface module supports Modbus RTU or IEC 61850-9-2LE protocol for uploading real-time health status of the metal oxide varistor, historical surge event records, and current working path identification information to the upper-level monitoring system. Each time the central coordinating controller detects a valid interrupt signal from the clamping voltage monitoring unit, it automatically records the event occurrence time, duration, peak leakage current, and corresponding temperature value, and writes the data to the circular buffer of the non-volatile memory unit, which can store the complete parameter set of the most recent one thousand surge events. The non-volatile memory unit uses ferroelectric random access memory (FRAM), which has high write endurance and power-loss data retention capability, ensuring that event records are not lost during long-term operation.

[0035] During each system power-on initialization phase, the central coordinating controller executes a self-test procedure to verify the functional integrity of the first MOSFET switch, the second MOSFET switch, and the status sensing module. The self-test process includes: applying a test pulse to the first MOSFET switch to check if its on-state voltage drop is within the normal range; applying a reverse bias to the second MOSFET switch to verify if its turn-off impedance is higher than a set threshold; injecting a standard test current into the leakage current sampling unit to verify the differential amplifier gain error; reading the output value of the temperature sensing unit at room temperature to determine if it is within the calibration range; and triggering the reference voltage source switching of the clamping voltage monitoring unit to confirm the correct response of the high-speed comparator. If any critical component is detected to have an open circuit, short circuit, or abnormal signal, the central coordinating controller immediately locks all output drive signals and reports a fault code through the communication interface module to prevent operation with defects.

[0036] In one specific embodiment, the main discharge path uses a single metal oxide varistor with a rated voltage of 275V AC and a maximum discharge current of 40kA (8 / 20μs waveform), whose static leakage current does not exceed 10μA at an ambient temperature of 25℃. The first field-effect transistor switch is an N-channel MOSFET with a withstand voltage of 650V and an on-resistance of 15mΩ, packaged in TO-247 and mounted on a heat sink. The auxiliary discharge path uses a spare metal oxide varistor of the same specification to form a redundant branch with the second field-effect transistor switch. In the status sensing module, the sampling resistor has a resistance of 10mΩ and an accuracy of ±0.5%, and the differential amplifier gain is set to 100 times; the temperature sensing unit uses a DS18B20 digital temperature sensor with a temperature measurement range of -55℃ to +125℃ and a resolution of 0.0625℃; the reference voltage source of the clamping voltage monitoring unit is set to 385V DC, corresponding to the upper limit of the peak voltage of the 275V AC system. The central coordinating controller uses an STM32G474RET6 microcontroller with a main frequency of 170MHz, and has a built-in 12-bit ADC, high-resolution timer and hardware CRC check unit.

[0037] In the comparative example, a traditional transient overvoltage protection device without state sensing and reconfiguration functions consisted of only a single metal oxide varistor directly connected in parallel between the power input terminal and the ground bus, without any switch isolation or redundancy design. After experiencing multiple surge impacts, the leakage current continued to increase due to the performance degradation of the metal oxide varistor, eventually leading to thermal breakdown without triggering any warning, resulting in complete loss of protection function.

[0038] To verify the technical effectiveness of the present invention, accelerated aging and surge impact tests were conducted on the above embodiments and comparative examples. The test conditions were: ambient temperature 85℃, application of 1.15 times the rated AC voltage, and application of an 8 / 20μs, 20kA surge current impact every 24 hours. Table 1 lists the performance comparison data of the two types of devices after 500 hours of continuous operation.

[0039] Table 1: Performance Comparison of Examples and Comparative Examples

[0040]

[0041] Test results show that in the embodiment, the status awareness module accurately identified the initial performance degradation of the main discharge path. The central coordinating controller determined that the overall health index was below the failure threshold when the leakage current reached 12.6 μA, the temperature rise rate was 0.8℃ / min, and the clamping voltage offset was +3.1%. It successfully executed active isolation and reconfiguration operations, switching to the auxiliary discharge path without any protection interruption. In contrast, the comparative embodiment, lacking status monitoring and redundancy mechanisms, experienced irreversible thermal breakdown after the leakage current continued to increase to 215.3 μA, resulting in permanent failure of the protection function.

[0042] Furthermore, the device described in this invention exhibits excellent timing control performance during the switching process. By capturing the gate drive signal waveforms of the first MOSFET switch turning off and the second MOSFET switch turning on using a high-speed oscilloscope, the main switch turn-off delay was measured to be 8.3 nanoseconds and the auxiliary switch turn-on delay to be 42.7 nanoseconds, with an interval of less than 50 nanoseconds. Moreover, no significant fluctuation in the voltage to ground at the power input terminal was observed at the moment of switching, proving the existence of no protection window period.

[0043] In terms of communication functionality, the embodiment periodically reports its health status to the host computer via an RS-485 interface using the Modbus RTU protocol. The reported data frame includes the device address, the current working path identifier (0x01 for the main path, 0x02 for the auxiliary path), a comprehensive health index, the timestamp of the most recent surge event, and the peak leakage current. The host monitoring system can then perform remote status assessments and predictive maintenance scheduling based on this information.

[0044] Furthermore, the non-volatile storage unit of this invention pre-stores multiple failure criterion models, each applicable to different application scenarios. For example, for industrial motor drive systems, the model assigns a higher weight to the temperature rise rate; for data center power supplies, the model focuses more on the long-term stability of leakage current. The central coordinating controller can load the corresponding model according to configuration instructions to achieve intelligent criterion adaptation for applications.

[0045] In summary, this invention constructs a highly reliable, long-life, and monitorable transient overvoltage protection device by combining hardware cascaded control logic and multi-path redundancy design with embedded state awareness and millisecond-level dynamic reconfiguration strategies. Its technical solution is highly feasible in engineering implementation; all components are industrial-grade standard devices, and the control algorithm is embedded in the microcontroller firmware, requiring no external intervention. It is suitable for applications with stringent power supply safety requirements, such as smart grids, industrial IoT nodes, edge computing servers, and high-reliability manufacturing equipment.

[0046] The above embodiments are merely explanations of the present invention and are not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to these embodiments without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A transient overvoltage protection device with active isolation and reconfiguration functions, characterized in that, include: The main discharge path and auxiliary discharge path between the power input terminal and the ground bus; The main discharge path includes a first metal oxide varistor and a first field-effect transistor switch. The first field-effect transistor switch is an N-channel enhancement-mode power MOSFET, whose drain is connected to the power input terminal and whose source is connected to the input terminal of the first metal oxide varistor. The output terminal of the first metal oxide varistor is connected to the ground bus. The auxiliary discharge path includes a parallel branch consisting of a second field-effect transistor switch and a spare metal oxide varistor, or an independent discharge path consisting of a gas discharge tube and a current-limiting inductor connected in series. The state sensing module includes a leakage current sampling unit, a temperature sensing unit, and a clamping voltage monitoring unit, which are used to collect the leakage current, surface temperature, and input voltage of the first metal oxide varistor, respectively. The central coordinating controller has its signal input terminal connected to the state sensing module, and its output terminal connected to the gate of the first field-effect transistor switch, the gate of the second field-effect transistor switch, or the high-voltage pulse excitation circuit of the gas discharge tube, respectively. The central coordinating controller is configured to: calculate a comprehensive health index based on the leakage current, temperature and clamping voltage, and when the index is lower than a preset failure threshold, first turn off the first field-effect transistor switch to isolate the first metal oxide varistor, and then activate the auxiliary discharge path, and the time interval between the main path shutdown and the auxiliary path activation does not exceed fifty nanoseconds.

2. The transient overvoltage protection device with active isolation and reconfiguration function according to claim 1, characterized in that, The leakage current sampling unit includes a high-precision sampling resistor connected in series in the grounding loop of the first metal oxide varistor, and a differential amplifier connected across the two ends of the sampling resistor. The output of the differential amplifier is connected to the analog signal input interface of the central coordinating controller.

3. The transient overvoltage protection device with active isolation and reconfiguration function according to claim 1, characterized in that, The temperature sensing unit is a thermistor or digital temperature sensor mounted on the surface of the first metal oxide varistor, and its signal output terminal is connected to the temperature acquisition channel of the central coordinating controller.

4. A transient overvoltage protection device with active isolation and reconfiguration function according to claim 1, characterized in that, The clamping voltage monitoring unit includes a high-speed comparator and a reference voltage source. The positive input terminal of the high-speed comparator is connected to the input terminal of the first metal oxide varistor, the negative input terminal is connected to the reference voltage source, and the output terminal is connected to the digital interrupt pin of the central coordinating controller.

5. A transient overvoltage protection device with active isolation and reconfiguration function according to claim 1, characterized in that, When the auxiliary discharge path adopts a gas discharge tube and current limiting inductor structure, one end of the gas discharge tube is connected to the power input terminal, and the other end is connected to the ground busbar through the current limiting inductor, and its trigger end is connected to the high-voltage pulse excitation circuit controlled by the central coordinating controller.

6. A transient overvoltage protection device with active isolation and reconfiguration function according to claim 1, characterized in that, The main discharge path and the auxiliary discharge path are symmetrically arranged, and the trace length, width and stack-up structure from the power input terminal to their respective discharge elements are consistent, so as to match the parasitic inductance and distributed capacitance parameters.

7. A transient overvoltage protection device with active isolation and reconfiguration function according to claim 1, characterized in that, The first metal oxide varistor, the first field-effect transistor switch, the spare metal oxide varistor, and the second field-effect transistor switch are all mounted on the same heat dissipation substrate, which is bonded to the metal casing with thermal grease.

8. A transient overvoltage protection device with active isolation and reconfiguration function according to claim 1, characterized in that, The grounding bus is a low-impedance copper bus with a cross-sectional area of ​​not less than 25 square millimeters and a tin-plated surface.

9. A transient overvoltage protection device with active isolation and reconfiguration function according to claim 1, characterized in that, It also includes a communication interface module, which is an RS-485 bus transceiver or an Ethernet physical layer chip. Its data port is connected to the serial communication peripheral of the central coordinating controller for uploading real-time health status, surge event records and current working path identification information.

10. A transient overvoltage protection device with active isolation and reconfiguration function according to claim 1, characterized in that, The central coordinating controller executes a self-test program during system power-on initialization to verify the functional integrity of the first field-effect transistor switch, the second field-effect transistor switch, and the status sensing module. When an anomaly is detected, all output drive signals are locked and a fault code is reported through the communication interface module.

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