Active surge protection circuit and surge suppression method

Abstract

The application discloses an active surge protection circuit and a surge suppression method, and belongs to the technical field of circuit protection. The active surge protection circuit calculates the energy of an input surge based on the voltage and current parameters of the input surge in real time through an energy determination module, judges the energy, and acquires accurate current parameters in cooperation with a current acquisition module. A trigger signal can be generated rapidly when the surge energy reaches a risk threshold. An energy offset module responds immediately, controls an energy storage unit to accurately inject the pre-stored electrical energy in the form of a reverse current into the surge input line, directly offsets and cancels part of the invading surge energy, and effectively reduces the change rate of the surge voltage. The process actively shares the energy required to be absorbed by the traditional passive protection device at the back end, greatly reduces the instantaneous current and thermal stress it bears, significantly prolongs the service life of the passive device, improves the tolerance of the entire circuit system to high-energy surges and the operation reliability, and realizes the improvement of the protection level from passive absorption to active offset.

Description

Technical Field

[0001] This application relates to the field of circuit protection technology, and in particular to active surge protection circuits and surge suppression methods. Background Technology

[0002] In the field of circuit protection technology, traditional surge protection mainly relies on passive protection devices such as TVS (Transient Voltage Suppressor), varistors, or silicon controlled rectifiers. These devices quickly conduct when the surge voltage exceeds their clamping voltage, clamping the surge peak voltage to a certain level and dissipating the surge energy as heat. However, this type of passive protection has inherent limitations: firstly, the energy absorption capacity of a single device is limited (for example, the single-pulse energy handling capacity of a typical TVS device is usually on the order of 1 joule), making it difficult to independently cope with high-energy surges; secondly, during the protection process, most of the surge energy still needs to be absorbed by the downstream protected equipment or borne by the protective device itself, resulting in the protective device being subjected to severe instantaneous thermal shocks, which can easily deteriorate or even be damaged with long-term use, thus shortening the lifespan and reliability of the overall protection system and restricting further improvement of equipment protection capabilities. Therefore, how to break through the energy absorption limit of passive protection and effectively reduce the stress on core protective devices has become a key issue in improving the surge withstand reliability of equipment. Summary of the Invention

[0003] To address the limitations of existing surge protection devices in energy absorption capacity and the fact that surge energy is primarily absorbed by the protected equipment, leading to increased susceptibility to thermal shock and shortened lifespan, this paper presents an active surge protection circuit and surge suppression method. This method aims to proactively trigger and control an energy storage unit to inject reverse current into the input line before the passive protection device reaches its risk threshold, based on real-time calculated surge energy. This counteracts a portion of the surge energy, significantly reducing stress and thermal damage to the passive device. Furthermore, it extends the device's lifespan by reducing the surge voltage change rate to distribute energy.

[0004] This application provides an active surge protection circuit, including:

[0005] The energy determination module, connected to the surge input terminal, is used to calculate the energy parameters of the input surge based on its voltage and current parameters, and generate a trigger signal.

[0006] A current acquisition module is connected between the surge input terminal and the current input terminal of the energy determination module. It is used to acquire the current parameters of the surge input terminal and send the current parameters to the energy determination module.

[0007] An energy cancellation module is connected to the surge input terminal, the energy determination module, the current acquisition module, and the power ground, respectively. In response to the trigger signal, it controls the energy storage unit to release the stored electrical energy to the surge input terminal in the form of reverse current to cancel out part of the surge energy, thereby reducing the voltage change rate of the input surge.

[0008] Optionally, the energy cancellation module includes:

[0009] An energy storage unit is connected between the surge input terminal and the power ground.

[0010] The energy replenishment unit is connected to the energy storage unit, the energy determination module, the surge input terminal, and the power ground, respectively. In response to the trigger signal, it releases the electrical energy stored in the energy storage unit to the surge input terminal in the form of reverse current to offset part of the surge energy.

[0011] Optionally, the energy storage unit includes:

[0012] A first capacitor, the positive terminal of which is connected to the surge input terminal, and the negative terminal of which is connected to the power ground;

[0013] The second capacitor has its negative terminal connected to the surge input terminal and its positive terminal connected to the power supply ground.

[0014] Optionally, the energy replenishment unit includes:

[0015] A first switch, one end of which is connected to the surge input terminal, and the other end of which is connected to the positive terminal of the first capacitor;

[0016] A second switch, one end of which is connected to the negative terminal of the first capacitor;

[0017] The first DC power supply, the positive terminal of the first DC power supply, together with the other end of the first switch, the positive terminal of the first capacitor, and the other end of the second switch, forms the first input terminal of the energy cancellation module and is connected to the power ground and the first output terminal of the energy determination module; the negative terminal of the first DC power supply is connected to the negative terminal of the first capacitor.

[0018] A third switch, one end of which is connected to the surge input terminal, and the other end of which is connected to the negative terminal of the second capacitor;

[0019] A fourth switch, one end of which is connected to the positive terminal of the second capacitor;

[0020] The second DC power supply, the negative terminal of which together with the other end of the third switch, the negative terminal of the second capacitor, and the other end of the fourth switch forms the second input terminal of the energy cancellation module and is connected to the power ground and the second output terminal of the energy determination module. The positive terminal of the second DC power supply is connected to the positive terminal of the second capacitor.

[0021] Optionally, the energy determination module includes:

[0022] A first Zener diode, wherein the first terminal of the first Zener diode is connected to the surge input terminal;

[0023] The second Zener diode has its first terminal connected to the second terminal of the first Zener diode, and its second terminal is connected to one end of the current acquisition module, one end of the energy cancellation module, and the power supply ground.

[0024] The first operational amplifier has its non-inverting input terminal connected to a positive power supply terminal and a positive bias power supply terminal, its inverting input terminal connected to the second terminal of the first Zener diode and the first terminal of the second Zener diode, and its negative power supply terminal connected to power ground.

[0025] The second operational amplifier has its non-inverting input terminal connected to the positive power supply terminal and the power supply ground, its inverting input terminal connected to the second terminal of the first Zener diode and the first terminal of the second Zener diode, and its negative power supply terminal connected to a negative bias power supply.

[0026] The control unit has a first input terminal connected to the output terminal of the first operational amplifier, a second input terminal connected to the output terminal of the second operational amplifier, a third input terminal forming the current input terminal of the energy determination module and connected to the current output terminal of the current acquisition module, a first output terminal connected to the first input terminal of the energy cancellation module, and a second output terminal connected to the second input terminal of the energy cancellation module.

[0027] Optionally, the energy determination module further includes:

[0028] A first resistor, one end of which is connected to the second end of the first Zener diode;

[0029] The second resistor has one end connected to the other end of the first resistor, the inverting input terminal of the first operational amplifier, and the inverting input terminal of the second operational amplifier, and the other end connected to the first end of the second Zener diode.

[0030] Optionally, the energy determination module further includes:

[0031] The first diode has its anode connected to the other end of the first resistor and one end of the second resistor, and its cathode connected to the inverting input terminal of the first operational amplifier.

[0032] The second diode has its cathode connected to the other end of the first resistor and one end of the second resistor, and its anode connected to the inverting input terminal of the second operational amplifier.

[0033] Optional, also includes:

[0034] A bidirectional thyristor device, wherein the first end of the bidirectional thyristor device is connected to the surge input terminal and the first end of the first Zener diode, the second end of the bidirectional thyristor device is connected to the current acquisition module, and the third end of the bidirectional thyristor device is connected to one end of the second resistor and the other end of the first resistor.

[0035] Optionally, the control unit is further configured to acquire the voltage and current signals of the bidirectional thyristor device, and integrate the voltage and current signals based on time parameters to determine the energy value; the condition for the control unit to generate the trigger signal includes the energy value reaching a preset threshold.

[0036] This application also provides a surge suppression method applied to the above-mentioned active surge protection circuit, comprising:

[0037] Real-time monitoring of input surge voltage and current parameters, and calculation of their energy parameters;

[0038] When the energy parameters indicate that the surge energy reaches a preset condition, a trigger signal is generated;

[0039] In response to the trigger signal, the control energy storage unit injects pre-stored electrical energy into the surge input line in the form of reverse current to actively offset part of the surge energy, thereby reducing the voltage change rate of the input surge.

[0040] The beneficial effects of the above technical solution are as follows:

[0041] In this technical solution, the active surge protection circuit of this application calculates and judges the energy of the input surge in real time based on the voltage and current parameters of the input surge through an energy determination module, and obtains accurate current parameters in conjunction with a current acquisition module. This enables the circuit to quickly generate a trigger signal when the surge energy reaches a risk threshold. The energy cancellation module then responds, controlling the energy storage unit to precisely inject pre-stored electrical energy into the surge input line in the form of a reverse current, thereby directly offsetting and canceling part of the intruding surge energy and effectively reducing the rate of change of surge voltage (dv / dt). This process actively shares the energy that traditional passive protection devices (such as TVS or thyristors) need to absorb, significantly reducing the instantaneous current and thermal stress they bear, significantly extending the service life of passive devices, and improving the overall circuit system's tolerance to high-energy surges and operational reliability. This achieves a protection level upgrade from passive absorption to active cancellation. Attached Figure Description

[0042] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0043] Figure 1 This is a circuit diagram of one embodiment of the active surge protection circuit described in this application;

[0044] Figure 2 This is a flowchart illustrating one embodiment of the surge suppression method described in this application.

[0045] The names of the parts referred to by the numbers in the attached diagram are as follows:

[0046] Energy cancellation module 1, energy determination module 2, control unit 21, first capacitor C1, second capacitor C2, first switch S1, second switch S2, third switch S3, fourth switch S4, first DC power supply DC1, second DC power supply DC2, first Zener diode D1, second Zener diode D11, third Zener diode D2, fourth Zener diode D4, first diode D6, second diode D7, third diode D3, fourth diode D5, first resistor R1, second resistor R2, third resistor R3, fourth resistor R4, fifth resistor R5, sixth resistor R6, seventh resistor R7, eighth resistor R8, first operational amplifier U1, second operational amplifier U2, current acquisition module CT, bidirectional thyristor device T1. Detailed Implementation

[0047] The advantages of this application are further illustrated below with reference to the accompanying drawings and specific embodiments.

[0048] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0049] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0050] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0051] In the description of this application, it should be understood that the numerical labels before the steps do not indicate the order of the steps, but are only used to facilitate the description of this application and to distinguish each step, and therefore should not be construed as a limitation of this application.

[0052] See Figure 1 As shown, this application provides an active surge protection circuit, including:

[0053] Energy determination module 2, connected to the surge input terminal, is used to calculate the energy parameters of the input surge based on the voltage and current parameters, and generate a trigger signal;

[0054] The current acquisition module CT is connected between the surge input terminal and the current input terminal of the energy determination module 2. It is used to acquire the current parameters of the surge input terminal and send the current parameters to the energy determination module 2.

[0055] The energy cancellation module 1 is connected to the surge input terminal, the energy determination module 2, the current acquisition module CT, and the power ground, respectively. In response to the trigger signal, it controls the energy storage unit to release the stored electrical energy to the surge input terminal in the form of reverse current to cancel part of the surge energy, thereby reducing the voltage change rate of the input surge.

[0056] In this embodiment, the active surge protection circuit calculates and judges the energy of the input surge in real time based on the voltage and current parameters of the input surge through the energy determination module 2, and obtains accurate current parameters in conjunction with the current acquisition module CT. This enables the circuit to quickly generate a trigger signal when the surge energy reaches the risk threshold. The energy cancellation module 1 then responds, controlling the energy storage unit to precisely inject pre-stored electrical energy into the surge input line in the form of reverse current, thereby directly offsetting and canceling part of the intruding surge energy and effectively reducing the rate of change of surge voltage (dv / dt). This process actively shares the energy that traditional passive protection devices (such as TVS or thyristors) need to absorb, significantly reducing the instantaneous current and thermal stress they bear, significantly extending the service life of passive devices, and improving the overall circuit system's tolerance to high-energy surges and operational reliability. This achieves a protection level upgrade from passive absorption to active cancellation.

[0057] In a preferred embodiment, the energy cancellation module 1 includes:

[0058] An energy storage unit is connected between the surge input terminal and the power ground to store electrical energy in advance when the circuit is working normally.

[0059] The energy replenishment unit is connected to the energy storage unit, the energy determination module 2, the surge input terminal and the power ground respectively. In response to the trigger signal, it releases the electrical energy stored in the energy storage unit to the surge input terminal in the form of reverse current to offset part of the surge energy.

[0060] In this embodiment, when the trigger signal generated by the energy determination module 2 is issued, the energy replenishment unit responds quickly and precisely controls the pre-stored electrical energy in the energy storage unit, releasing it to the surge input terminal in the form of a reverse current with the opposite polarity to the input surge. This process achieves immediate and active cancellation of intrusive surge energy, rather than simply relying on the absorption of back-end devices, thereby significantly reducing the impact of surge peaks on the protection circuit and improving the overall system's protection capacity and operational reliability.

[0061] In a preferred embodiment, the energy storage unit may include: a first capacitor C1 and a second capacitor C2;

[0062] A first capacitor C1, the positive terminal of the first capacitor C1 is connected to the surge input terminal, and the negative terminal of the first capacitor C1 is connected to the power supply ground;

[0063] The second capacitor C2 has its negative terminal connected to the surge input terminal and its positive terminal connected to the power supply ground.

[0064] In this embodiment, the energy storage unit consists of a first capacitor C1 and a second capacitor C2. The symmetrical connection structure of the first capacitor C1 and the second capacitor C2 enables the energy storage unit to pre-store electrical energy in the corresponding directions of positive and negative surges, ensuring a rapid response capability to bidirectional surges. By flexibly configuring the capacitance values ​​of these two capacitors according to the actual protection level requirements (e.g., from 1000uF or 2000uF), the energy reserve scale of the energy storage unit can be precisely adjusted to match the expected surge energy level. This not only optimizes the space and cost efficiency of the circuit but also ensures that sufficient and controllable reserve energy is available for use when a surge event occurs, thereby providing a stable and reliable energy source for subsequent active energy cancellation and enhancing the adaptability and protection margin of the entire protection circuit.

[0065] In a preferred embodiment, the energy replenishment unit includes:

[0066] A first switch S1, one end of which is connected to the surge input terminal, and the other end of which is connected to the positive terminal of the first capacitor C1;

[0067] The second switch S2, one end of which is connected to the negative terminal of the first capacitor C1;

[0068] The first DC power supply DC1, the positive terminal of the first DC power supply DC1, together with the other end of the first switch S1, the positive terminal of the first capacitor C1, and the other end of the second switch S2, forms the first input terminal of the energy cancellation module 1 and is connected to the power ground and the first output terminal of the energy determination module 2. The negative terminal of the first DC power supply DC1 is connected to the negative terminal of the first capacitor C1.

[0069] The third switch S3, one end of which is connected to the surge input terminal, and the other end of which is connected to the negative terminal of the second capacitor C2;

[0070] The fourth switch S4, one end of which is connected to the positive terminal of the second capacitor C2;

[0071] The second DC power supply DC2, the negative terminal of the second DC power supply DC2, together with the other end of the third switch S3, the negative terminal of the second capacitor C2, and the other end of the fourth switch S4, forms the second input terminal of the energy cancellation module 1 and is connected to the power ground and the second output terminal of the energy determination module 2. The positive terminal of the second DC power supply DC2 is connected to the positive terminal of the second capacitor C2.

[0072] In this embodiment, the energy replenishment unit achieves rapid energy release through precise switch control: when the energy determination module 2 sends a first trigger signal for a positive surge, it controls the first switch S1 and the second switch S2 to close, forming a parallel circuit between the first capacitor C1, the first DC power supply DC1, and the surge input terminal. The stored energy in the capacitor is then injected into the line as a reverse current in conjunction with the output of the DC power supply. For a second trigger signal for a negative surge, it controls the third switch S3 and the fourth switch S4 to close, achieving parallel release of the second capacitor C2 and the second DC power supply DC2. This structure ensures a rapid and directional response to bidirectional surges. By actively injecting reverse current during the surge's rising edge, it can directly offset and cancel out some of the surge energy. This significantly reduces the rate of change of surge voltage (dv / dt), thereby greatly weakening the transient impact and stress of the surge pulse on the downstream load equipment, improving the smoothness of protection and overall reliability.

[0073] In a preferred embodiment, the energy determination module 2 includes:

[0074] A first Zener diode D1, the first terminal of which is connected to the surge input terminal;

[0075] The second Zener diode D11 has its first terminal connected to the second terminal of the first Zener diode D1, and its second terminal is connected to one end of the current acquisition module CT, one end of the energy cancellation module 1, and the power ground.

[0076] The first operational amplifier U1 has its non-inverting input terminal connected to a positive bias power supply (+3.3V) and its inverting input terminal connected to the second terminal of the first Zener diode D1 and the first terminal of the second Zener diode D11. The negative power supply terminal of the first operational amplifier U1 is connected to the power supply ground.

[0077] The second operational amplifier U2 has its non-inverting input terminal connected to the positive power supply terminal and the power supply ground. Its inverting input terminal is connected to the second terminal of the first Zener diode D1 and the first terminal of the second Zener diode D11. The negative power supply terminal of the second operational amplifier U2 is connected to a negative bias power supply (-3.3V).

[0078] Control unit 21, the first input terminal of control unit 21 is connected to the output terminal of the first operational amplifier U1, the second input terminal of control unit 21 is connected to the output terminal of the second operational amplifier U2, the third input terminal of control unit 21 forms the current input terminal of the energy determination module 2 and is connected to the current output terminal of the current acquisition module CT, the first output terminal of control unit 21 is connected to the first input terminal of the energy cancellation module 1, and the second output terminal of control unit 21 is connected to the second input terminal of the energy cancellation module 1.

[0079] In this embodiment, the energy determination module 2 of this preferred embodiment employs a detection network composed of a first Zener diode D1 and a second Zener diode D11 connected in series. Combined with the first operational amplifier U1, the second operational amplifier U2, and the control unit 21, it achieves accurate sensing and intelligent judgment of input surges. The first Zener diode D1 and the second Zener diode D11 can be bidirectional Zener diodes with a clamping voltage of 15V to ensure reliable operation of the circuit within the protection start-up voltage range of 20V to 22V, and to stably limit the conduction current to within 40mA, balancing sensitivity and safety. The two operational amplifiers are respectively configured with positive and negative bias power supplies, enabling them to independently and quickly respond to positive and negative surge events and convert them into clear level transition signals for output. The control unit 21 synchronously receives the voltage event signal and real-time current parameters from the current acquisition module CT, thereby quickly and accurately calculating the surge energy and generating corresponding trigger commands. This structure enables real-time monitoring and polarity determination of bidirectional surges. Its rapid response and accurate determination provide a reliable guarantee for the timely and directional action of the subsequent energy cancellation module 1. It is the key control core that enables the entire active protection system to achieve efficient and reliable counter-current intervention.

[0080] In a preferred embodiment, the energy determination module 2 may further include: a first resistor R1 and a second resistor R2;

[0081] The first resistor R1, one end of which is connected to the second end of the first Zener diode D1;

[0082] The second resistor R2 has one end connected to the other end of the first resistor R1, the inverting input terminal of the first operational amplifier U1, and the inverting input terminal of the second operational amplifier U2. The other end of the second resistor R2 is connected to the first end of the second Zener diode D11.

[0083] In this embodiment, the energy determination module 2 may further include a first resistor R1 and a second resistor R2. These resistors, each with a resistance of 150 ohms, are connected in series between the first Zener diode D1 and the second Zener diode D11, and their common connection point is simultaneously connected to the inverting input terminals of both the first and second operational amplifiers U2. These two resistors act as current-limiting and voltage-dividing resistors, constructing a stable detection network. Their core function is to effectively limit the current flowing through the downstream Zener diodes when a surge voltage is applied to the detection network, ensuring that they operate within a safe current range, thereby protecting the core detection device from large current surges. Simultaneously, they pre-divide the input signal, providing a stable and appropriate detection voltage for the operational amplifiers, improving the accuracy of voltage comparison and anti-interference capability. This configuration significantly enhances the reliability and durability of the detection circuit, laying a solid foundation for the long-term, stable, and accurate operation of the entire energy determination module 2 under various severe surge conditions, thus ensuring the accuracy of the active cancellation trigger timing and the consistency of system protection.

[0084] In a preferred embodiment, the energy determination module 2 further includes:

[0085] The first diode D6 has its anode connected to the other end of the first resistor R1 and one end of the second resistor R2, and its cathode connected to the inverting input terminal of the first operational amplifier U1.

[0086] The second diode D7 has its cathode connected to the other end of the first resistor R1 and one end of the second resistor R2, and its anode connected to the inverting input terminal of the second operational amplifier U2.

[0087] Furthermore, the energy determination module 2 may also include:

[0088] The third Zener diode D2 has its anode connected to the power supply ground, and its cathode connected to the cathode of the first diode D6 and the inverting input terminal of the first operational amplifier U1.

[0089] The fourth Zener diode D4 is connected to the positive terminal of the second diode D7 and the inverting input terminal of the second operational amplifier U2, and the negative terminal of the fourth Zener diode D4 is connected to the power supply ground.

[0090] In this embodiment, the energy determination module 2 further incorporates a protection and isolation network consisting of a first diode D6, a second diode D7, a third Zener diode D2, and a fourth Zener diode D4. The first diode D6 and the second diode D7 are connected between the detection node and the inverting inputs of the two operational amplifiers, respectively. Utilizing their unidirectional conductivity, they achieve electrical isolation between the positive and negative surge detection signal paths, effectively preventing crosstalk between bidirectional surge signals at the input and ensuring the purity and accuracy of polarity determination. Furthermore, the third and fourth Zener diodes D4 are connected in parallel between the inverting inputs of the two operational amplifiers and the power supply ground, respectively. Their 3.3V clamping voltage provides precise voltage limiting protection for the input. This combination effectively suppresses potentially excessive transient voltages, reliably protecting sensitive components such as the downstream operational amplifiers from accidental overvoltage surges. It significantly enhances the robustness and long-term operational stability of the entire determination circuit in harsh electromagnetic environments, thereby ensuring the continuous and reliable operation of the energy calculation and triggering logic.

[0091] In a preferred embodiment, the energy determination module 2 may further include: a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a third diode D3, and a fourth diode D5;

[0092] One end of the third resistor R3 is connected to the cathode of the first diode D6, and the other end of the third resistor R3 is connected to the cathode of the third Zener diode D2; one end of the seventh resistor R7 is connected to the inverting input terminal of the first operational amplifier U1 and the cathode of the third Zener diode D2, and the other end of the seventh resistor R7 is connected to the power supply ground; one end of the fourth resistor R4 is connected to the non-inverting input terminal and the positive power supply terminal of the first operational amplifier U1, and the other end of the fourth resistor R4 is connected to the anode of the third diode D3, and the cathode of the third diode D3 is connected to the power supply ground;

[0093] One end of the sixth resistor R6 is connected to the anode of the second diode D7, and the other end of the sixth resistor R6 is connected to the anode of the fourth Zener diode D4, one end of the eighth resistor R8, and the inverting input of the second operational amplifier U2; the other end of the eighth resistor R8 is connected to the negative bias power supply; the anode of the fourth diode D5 is connected to the power supply ground, and the cathode of the fourth diode D5 is connected to the non-inverting input of the second operational amplifier U2 and one end of the fifth resistor R5; the other end of the fifth resistor R5 is connected to the negative bias power supply.

[0094] Both the seventh resistor R7 and the eighth resistor R8 are pull-down resistors to ensure that the initial level of the op-amp's - terminal is low. R7 = R8 = 100K ohm.

[0095] The third diode D3 and the fourth diode D5 are forward-biased, providing a stable +0.7V / -2.6V voltage to the op-amp reference potential; the fourth resistor R4 and the fifth resistor R5 are current-limiting resistors.

[0096] In this embodiment, the seventh resistor R7 and the eighth resistor R8 act as pull-down resistors, ensuring that the inverting input terminals of the first and second operational amplifiers U2 have a clear low initial potential, effectively preventing false triggering caused by power-on or interference. The third diode D3 and the fourth diode D5 utilize their forward voltage drop characteristics to provide stable and accurate +0.7V and -2.6V reference voltages to the non-inverting input terminals of the two operational amplifiers, respectively. This establishes a stable and accurate comparison benchmark for surge voltage detection, significantly improving the consistency of polarity discrimination and trigger level. The third, fourth, fifth, and sixth resistors R6 play a role in current limiting and signal conditioning in the circuit. They collectively optimize the signal path, protecting the subsequent Zener diodes and operational amplifier input terminals from current surges while ensuring the purity and stability of the detected voltage signal. The addition of this component makes the DC operating point of the entire energy determination module 2 more stable, the comparator threshold more accurate, and significantly enhances the circuit's anti-interference capability and long-term operational stability in complex noise environments, thereby ensuring the high reliability and accuracy of energy calculation and trigger decision-making.

[0097] In a preferred embodiment, it further includes:

[0098] A bidirectional thyristor T1 is provided, wherein the first end of the bidirectional thyristor T1 is connected to the surge input terminal and the first end of the first Zener diode D1, the second end of the bidirectional thyristor T1 is connected to the current acquisition module CT, and the third end of the bidirectional thyristor T1 is connected to one end of the second resistor R2 and the other end of the first resistor R1.

[0099] In this embodiment, the first terminal of the bidirectional thyristor T1 is connected to the surge input terminal, the second terminal is connected to the current acquisition module CT, and the third terminal is connected to the voltage divider resistor network in the energy determination module 2. The bidirectional thyristor T1 is set with a specific gate trigger voltage (5V) and cutoff voltage (15V), forming a fast, passive discharge channel. Its operation works in conjunction with the aforementioned active cancellation mechanism: when the surge voltage exceeds its trigger threshold, the bidirectional thyristor quickly conducts, directly and quickly discharging part of the surge energy to ground, achieving initial clamping and energy diversion of the surge voltage peak. This discharge path effectively alleviates the pressure on the subsequent active energy cancellation module 1, providing the control circuit with more stable response conditions. The combination of the two forms a multi-level collaborative protection architecture of "passive fast clamping discharge" and "active precise energy offsetting," which not only significantly reduces the surge stress applied to the final protected device but also optimizes the energy processing and distribution of the overall protection system, greatly improving the overall robustness and reliability of the system in dealing with high-intensity, high-energy surge events.

[0100] In a preferred embodiment, the control unit 21 is further configured to acquire the voltage signal and current signal of the bidirectional thyristor device T1, and integrate the voltage signal and the current signal based on a time parameter to determine an energy value; the condition for the control unit 21 to generate the trigger signal includes the energy value reaching a preset threshold.

[0101] In this embodiment, the control unit 21 synchronously acquires the real-time voltage signal v(t) across the bidirectional thyristor device T1 and the current signal i(t) flowing through it at a fixed sampling frequency, and continuously calculates its cumulative energy value E(t) using a numerical integration algorithm. Whether this real-time energy value reaches a preset threshold is used as one of the core conditions for generating a trigger signal, achieving a precise and quantitative assessment of the surge threat level, thereby driving subsequent active cancellation actions. Simultaneously, the first DC power supply DC1 and the second DC power supply DC2 constitute an automatic energy replenishment circuit. When the corresponding switch is turned on, the power supply can continuously replenish the first capacitor C1 or the second capacitor C2, ensuring that the energy storage unit can quickly recover to its rated energy storage state during the action interval. This integrated control and energy replenishment strategy enables the system to not only achieve adaptive and precise trigger control based on accurate energy calculations, effectively avoiding the premature or late action problems that may exist with the traditional voltage threshold method, but also ensures the continuous availability of energy in the energy storage unit, thereby significantly improving the accuracy, adaptability, and long-term reliability of the entire active surge protection system.

[0102] In this embodiment, the energy determination module 2 (whose core is the control unit 21) acquires the voltage v(t) and current i(t) signals flowing through the bidirectional thyristor device T1 (as an example of a passive protection device) in real time, and integrates the product of the two signals over time according to the formula E = ∫(v(t) ×i(t)) dt, thereby accurately calculating the cumulative energy value of the surge event applied to the device. This calculation is typically performed by digitizing the analog signal using an analog-to-digital converter, and then the control unit 21 executes the numerical integration algorithm.

[0103] As an example, and not a limitation, energy assessment is performed using the output of a test signal generator as an example:

[0104] Surge parameters: open circuit voltage 6000V, source internal resistance 40Ω, waveform is 1.25 / 50 μs impulse wave.

[0105] Impact power calculation: P = V² / R = (6000V)² / 40Ω = 900,000W.

[0106] Impact energy calculation: The main energy is released during the wavefront time, therefore the energy released at the rising edge is approximately... .

[0107] Based on the above assessment, this application adopts a multi-level collaborative protection strategy:

[0108] Passive absorption: The bidirectional thyristor device T1 is activated first, which can quickly release most of the energy E_TVS (e.g., 0.8J).

[0109] Active cancellation: After passive peak reduction, the remaining energy needs to be processed by active energy cancellation module 1, i.e., E_active = E_surge - E_TVS = 1.125J - 0.8J = 0.325J, where E_active is the remaining energy.

[0110] This application allows for the calculation of the required capacitor value to provide 0.325J of compensation energy under a set residual voltage condition in the circuit, using the formula E = 1 / 2 × C × U². For example, if the residual voltage of the bus during compensation is U, calculations show that approximately 200μF of capacitor energy storage is sufficient to meet the requirements. This parameter provides a direct basis for the selection of energy storage units (such as the first capacitor C1 and the second capacitor C2).

[0111] The active surge protection circuit precisely releases the pre-stored electrical energy in the capacitor to the line through real-time control of the switches, directly offsetting or significantly reducing the rising edge energy of the surge pulse. The energy determination module 2 generates a determination signal based on the real-time calculated energy value, and selectively drives the switch pairs of the first switch S1, the second switch S2, or the third switch S3 and the fourth switch S4 to control the energy release of the corresponding path. Through the four switches, the control module for energy calculation, and the energy replenishment unit for the energy storage capacitor, a complete closed loop of surge energy acquisition, judgment, processing, and active offsetting is achieved.

[0112] The bidirectional thyristor T1 handles the initial rapid peak clamping and energy dissipation, while the active surge protection circuit subsequently performs the precise cancellation of the main energy. The two work together to optimize the protection effect. To achieve symmetrical protection against positive and negative polarity surges, the circuit employs a dual-channel active energy release structure, controlled by switch pairs of the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4, ensuring equal effectiveness against bidirectional surges. The system's control algorithm supports graded responses based on surge level. For example, when the calculated energy E < 0.5J, only event counting is performed; when 0.5J ≤ E < 0.8J, an early warning is issued; and when E ≥ 0.8J, active protection is triggered, thus achieving intelligent energy management.

[0113] Furthermore, the system incorporates a mechanism that automatically sets or adapts the energy storage capacitor capacity based on the remaining energy to be offset. The capacity of the energy storage capacitor can be calculated using the formula C = 2E / (V_cap²), where E is the energy to be offset, V_cap is the capacitor's operating voltage, and C is the capacity of the energy storage capacitor, which can be adjusted according to the residual energy requirement. By adjusting the capacity of the first capacitor C1 or the second capacitor C2 in the circuit accordingly, the entire protection circuit can flexibly adapt to surge environments of different levels and energies, significantly improving the versatility and configurability of the solution.

[0114] See Figure 2 As shown, this application provides a surge suppression method applied to the above-mentioned active surge protection circuit, comprising the following steps:

[0115] S1. Monitor the voltage and current parameters of the input surge in real time and calculate its energy parameters;

[0116] S2. When the energy parameters indicate that the surge energy reaches the preset condition, a trigger signal is generated;

[0117] S3. In response to the trigger signal, the energy storage unit is controlled to inject the pre-stored electrical energy into the surge input line in the form of reverse current to actively offset part of the surge energy, thereby reducing the voltage change rate of the input surge.

[0118] In this embodiment, the surge suppression method is mainly applied to the active surge protection circuit. The method first involves the energy determination module 2, in conjunction with the current acquisition module CT, executing step S1, which involves real-time synchronous monitoring of the voltage and current parameters of the input surge and calculating its energy parameters. When the energy parameters are determined to reach a preset threshold, the energy determination module 2 quickly generates a trigger signal. The energy cancellation module 1 then responds to this signal, controlling its energy storage unit to precisely inject pre-stored electrical energy into the surge input line in the form of a reverse current with the opposite polarity to the intrusive surge. This active cancellation process directly neutralizes a portion of the surge energy, significantly reducing the amplitude and rate of change (dv / dt) of the surge pulse, thereby weakening its impact intensity before it reaches the backend core protection devices and the protected equipment. This method transforms the traditional passive absorption mode into an intelligent intervention mode of "monitoring calculation-judgment-active cancellation," effectively distributing the energy burden of backend devices such as TVS, reducing their thermal stress, and extending their service life. Furthermore, it comprehensively improves the system's ability to suppress high-energy surges and the reliability of equipment operation.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An active surge protection circuit, characterized in that, include: The energy determination module, connected to the surge input terminal, is used to calculate the energy parameters of the input surge based on its voltage and current parameters, and generate a trigger signal. A current acquisition module is connected between the surge input terminal and the current input terminal of the energy determination module. It is used to acquire the current parameters of the surge input terminal and send the current parameters to the energy determination module. An energy cancellation module is connected to the surge input terminal, the energy determination module, the current acquisition module, and the power ground, respectively. In response to the trigger signal, it controls the energy storage unit to release the stored electrical energy to the surge input terminal in the form of reverse current to cancel out part of the surge energy, thereby reducing the voltage change rate of the input surge.

2. The active surge protection circuit according to claim 1, characterized in that, The energy cancellation module includes: An energy storage unit is connected between the surge input terminal and the power ground. The energy replenishment unit is connected to the energy storage unit, the energy determination module, the surge input terminal, and the power ground, respectively. In response to the trigger signal, it releases the electrical energy stored in the energy storage unit to the surge input terminal in the form of reverse current to offset part of the surge energy.

3. The active surge protection circuit according to claim 2, characterized in that, The energy storage unit includes: A first capacitor, the positive terminal of which is connected to the surge input terminal, and the negative terminal of which is connected to the power ground; The second capacitor has its negative terminal connected to the surge input terminal and its positive terminal connected to the power supply ground.

4. The active surge protection circuit according to claim 3, characterized in that, The energy replenishment unit includes: A first switch, one end of which is connected to the surge input terminal, and the other end of which is connected to the positive terminal of the first capacitor; A second switch, one end of which is connected to the negative terminal of the first capacitor; The first DC power supply, the positive terminal of the first DC power supply, together with the other end of the first switch, the positive terminal of the first capacitor, and the other end of the second switch, forms the first input terminal of the energy cancellation module and is connected to the power ground and the first output terminal of the energy determination module; the negative terminal of the first DC power supply is connected to the negative terminal of the first capacitor. A third switch, one end of which is connected to the surge input terminal, and the other end of which is connected to the negative terminal of the second capacitor; A fourth switch, one end of which is connected to the positive terminal of the second capacitor; The second DC power supply, the negative terminal of which together with the other end of the third switch, the negative terminal of the second capacitor, and the other end of the fourth switch forms the second input terminal of the energy cancellation module and is connected to the power ground and the second output terminal of the energy determination module. The positive terminal of the second DC power supply is connected to the positive terminal of the second capacitor.

5. The active surge protection circuit according to claim 1, characterized in that, The energy determination module includes: A first Zener diode, wherein the first terminal of the first Zener diode is connected to the surge input terminal; The second Zener diode has its first terminal connected to the second terminal of the first Zener diode, and its second terminal is connected to one end of the current acquisition module, one end of the energy cancellation module, and the power supply ground. The first operational amplifier has its non-inverting input terminal connected to a positive power supply terminal and a positive bias power supply terminal, its inverting input terminal connected to the second terminal of the first Zener diode and the first terminal of the second Zener diode, and its negative power supply terminal connected to power ground. The second operational amplifier has its non-inverting input terminal connected to the positive power supply terminal and the power supply ground, its inverting input terminal connected to the second terminal of the first Zener diode and the first terminal of the second Zener diode, and its negative power supply terminal connected to a negative bias power supply. The control unit has a first input terminal connected to the output terminal of the first operational amplifier, a second input terminal connected to the output terminal of the second operational amplifier, a third input terminal forming the current input terminal of the energy determination module and connected to the current output terminal of the current acquisition module, a first output terminal connected to the first input terminal of the energy cancellation module, and a second output terminal connected to the second input terminal of the energy cancellation module.

6. The active surge protection circuit according to claim 5, characterized in that, The energy determination module also includes: A first resistor, one end of which is connected to the second end of the first Zener diode; The second resistor has one end connected to the other end of the first resistor, the inverting input terminal of the first operational amplifier, and the inverting input terminal of the second operational amplifier, and the other end connected to the first end of the second Zener diode.

7. The active surge protection circuit according to claim 6, characterized in that, The energy determination module also includes: The first diode has its anode connected to the other end of the first resistor and one end of the second resistor, and its cathode connected to the inverting input terminal of the first operational amplifier. The second diode has its cathode connected to the other end of the first resistor and one end of the second resistor, and its anode connected to the inverting input terminal of the second operational amplifier.

8. The active surge protection circuit according to claim 6, characterized in that, Also includes: A bidirectional thyristor device, wherein the first end of the bidirectional thyristor device is connected to the surge input terminal and the first end of the first Zener diode, the second end of the bidirectional thyristor device is connected to the current acquisition module, and the third end of the bidirectional thyristor device is connected to one end of the second resistor and the other end of the first resistor.

9. The active surge protection circuit according to claim 8, characterized in that, The control unit is also used to acquire the voltage and current signals of the bidirectional thyristor device, and integrate the voltage and current signals based on time parameters to determine the energy value; the condition for the control unit to generate the trigger signal includes the energy value reaching a preset threshold.

10. A surge suppression method, applied to the active surge protection circuit described in claims 1-9, characterized in that, include: Real-time monitoring of input surge voltage and current parameters, and calculation of their energy parameters; When the energy parameters indicate that the surge energy reaches a preset condition, a trigger signal is generated; In response to the trigger signal, the control energy storage unit injects pre-stored electrical energy into the surge input line in the form of reverse current to actively offset part of the surge energy, thereby reducing the voltage change rate of the input surge.

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