Overvoltage protection system and overvoltage protection method

Abstract

The application discloses an overvoltage protection system and an overvoltage protection method. The system comprises a voltage reduction module, a voltage division module, a comparison module and a control module; the commercial power is connected with the voltage division module through the voltage reduction module, and the voltage division module is connected with the control module through the comparison module; the voltage reduction module is used for reducing the voltage of the commercial power to obtain a first voltage, wherein the first voltage is the input voltage of the voltage division module, the power supply voltage of the comparison module and the driving voltage of the control module; the voltage division module is used for dividing the first voltage to obtain a second voltage and a reference voltage; the comparison module is used for obtaining a driving signal according to the second voltage and the reference voltage; and the driving signal is used for driving the relay of the control module to disconnect the power supply between the commercial power and a target object. The application can relieve the damage to the monitoring device in the overvoltage protection process and improve the system safety. The application can be widely applied in the power safety technical field.

Description

Technical Field

[0001] This invention relates to the field of power safety technology, and in particular to an overvoltage protection system and overvoltage protection method. Background Technology

[0002] A switching power supply is a widely used power converter in electronic devices, used to convert alternating current (AC) into stable direct current (DC) for power supply. Its technological background stems primarily from the demand for efficient, portable, and stable power supplies, achieving power conversion through the on / off control of switching transistors. Overvoltage protection circuitry in switching power supplies is one of the core technologies ensuring power supply safety and reliability. As electronic devices increasingly demand higher power stability, overvoltage protection must respond quickly to abnormal input voltage or sudden load changes to prevent damage to power devices (such as IGBTs and MOSFETs) and downstream circuits due to excessive voltage.

[0003] In related technologies, overvoltage protection is achieved based on voltage divider sampling and voltage comparators, such as using comparators like the LM339 to monitor input or output voltage. When the detected value exceeds a preset threshold, overvoltage protection is achieved by blocking the drive signal or cutting off the main circuit. However, this solution cannot provide overvoltage protection for the monitoring device, which can easily damage the monitoring device and affect the safety performance of the system. Summary of the Invention

[0004] The purpose of this invention is to at least partially solve one of the technical problems existing in the prior art.

[0005] Therefore, the purpose of this invention is to provide a reliable overvoltage protection system and overvoltage protection method.

[0006] To achieve the above-mentioned technical objectives, the technical solutions adopted in the embodiments of the present invention include the following aspects:

[0007] On one hand, this invention provides an overvoltage protection system, including: a step-down module, a voltage divider module, a comparator module, and a control module; mains power is connected to the voltage divider module through the step-down module, the voltage divider module is connected to the control module through the comparator module, the step-down module is also connected to the comparator module, and the control module is connected to a target object; the step-down module is used to reduce the mains voltage to obtain a first voltage, wherein the first voltage is the input voltage of the voltage divider module, the supply voltage of the comparator module, and the drive voltage of the control module; the voltage divider module is used to divide the first voltage to obtain a second voltage and a reference voltage; the comparator module is used to obtain a drive signal based on the second voltage and the reference voltage; the drive signal is used to drive the relay of the control module to disconnect the power supply between the mains power and the target object. This application uses a step-down module to reduce the mains voltage, and then uses the voltage divider module, comparator module, and control module to achieve reliable overvoltage protection, which can mitigate damage to monitoring devices during overvoltage protection and improve system safety.

[0008] In addition, the overvoltage protection system according to the above embodiments of the present invention may also have the following additional technical features:

[0009] Furthermore, in the overvoltage protection system of this embodiment, the voltage divider module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and an adjustable Zener diode;

[0010] The first terminal of the first resistor is connected to the first voltage output terminal of the step-down module, and the second terminal of the first resistor is grounded; the first terminal of the second resistor is connected to the first terminal of the first resistor, and the second terminal of the second resistor is grounded through the third resistor, and the second terminal of the second resistor is used to output the second voltage; the first terminal of the fourth resistor is connected to the first terminal of the first resistor, and the second terminal of the fourth resistor is connected to the first terminal of the fifth resistor, and the second terminal of the fifth resistor is grounded through the sixth resistor; the anode of the adjustable Zener diode is grounded, the cathode of the adjustable Zener diode is connected to the second terminal of the fourth resistor, and the reference electrode of the adjustable Zener diode is connected to the second terminal of the fifth resistor; the cathode of the adjustable Zener diode is used to generate the reference voltage.

[0011] Furthermore, in one embodiment of the present invention, the voltage divider module further includes: a first Zener diode, the anode of the first Zener diode being connected to a first terminal of the first resistor, the cathode of the first Zener diode being grounded, and the first Zener diode being used to limit the first voltage.

[0012] Furthermore, in one embodiment of the present invention, the comparison module includes: a first comparator, the reference voltage output terminal of the voltage divider module is connected to the non-inverting input terminal of the first comparator, the second voltage output terminal of the voltage divider module is connected to the inverting input terminal of the first comparator, and the output terminal of the first comparator is used to output a relay drive signal.

[0013] Furthermore, in one embodiment of the present invention, the comparison module further includes: a second comparator, wherein the reference voltage output terminal is connected to the non-inverting input terminal of the second comparator, the output terminal of the first comparator is connected to the inverting input terminal of the second comparator, and the output terminal of the second comparator is connected to the first voltage output terminal of the buck module through a seventh resistor.

[0014] Furthermore, in one embodiment of the present invention, the control module includes a transistor, the output terminal of the first comparator is connected to the base of the transistor, the emitter of the transistor is connected to the first voltage output terminal, the collector of the transistor is connected to the coil of the relay, one end of the normally closed switch of the relay is connected to the mains power, and the other end of the normally closed switch is connected to the target object.

[0015] Furthermore, in one embodiment of the present invention, the difference between the resistance of the coil and the resistance of the seventh resistor is less than or equal to a preset difference.

[0016] On the other hand, embodiments of the present invention propose an overvoltage protection method, applied to the aforementioned overvoltage protection system, the method comprising:

[0017] The mains power is stepped down to obtain the first voltage;

[0018] Divide the first voltage to obtain the second voltage and the reference voltage;

[0019] A drive signal is obtained based on the second voltage and the reference voltage; the drive signal is used to drive the relay of the control module to disconnect the power supply between the mains power and the target object.

[0020] Furthermore, the overvoltage protection method of this embodiment of the invention further includes:

[0021] The first value is determined based on the ratio of the mains voltage to the capacitance value of the step-down module;

[0022] The first voltage is determined based on the product of the first value and the parallel resistance; the parallel resistance is related to the first, second, third, and fourth resistors of the voltage divider module and the seventh resistor of the comparator module.

[0023] The second voltage is determined based on the voltage division of the first voltage by the third resistor in the series branch of the second resistor and the third resistor.

[0024] Furthermore, the overvoltage protection method of this embodiment of the invention further includes:

[0025] Adjust the capacitance value, the first resistor, the second resistor, the third resistor, the fourth resistor, and the seventh resistor to determine the overvoltage protection threshold for generating the drive signal;

[0026] Alternatively, adjust the adjustable Zener diode to determine the overvoltage protection threshold for generating the drive signal.

[0027] On the other hand, embodiments of the present invention provide an overvoltage protection device, comprising:

[0028] At least one processor;

[0029] At least one memory for storing at least one program;

[0030] When the at least one program is executed by the at least one processor, the at least one processor implements the overvoltage protection method described above.

[0031] On the other hand, embodiments of the present invention provide a storage medium storing a processor-executable program, which, when executed by a processor, is used to implement the above-described overvoltage protection method.

[0032] The method provided in this invention includes: a step-down module, a voltage divider module, a comparison module, and a control module; mains power is connected to the voltage divider module through the step-down module, the voltage divider module is connected to the control module through the comparison module, the step-down module is also connected to the comparison module, and the control module is connected to a target object; the step-down module is used to reduce the voltage of the mains power to obtain a first voltage, wherein the first voltage is the input voltage of the voltage divider module, the supply voltage of the comparison module, and the drive voltage of the control module; the voltage divider module is used to divide the first voltage to obtain a second voltage and a reference voltage; the comparison module is used to obtain a drive signal based on the second voltage and the reference voltage; the drive signal is used to drive the relay of the control module to disconnect the power supply between the mains power and the target object. This application uses a step-down module to reduce the mains power, and then uses the voltage divider module, comparison module, and control module to achieve reliable overvoltage protection, which can mitigate damage to monitoring devices during overvoltage protection and improve system safety. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following description is provided with accompanying drawings of the relevant technical solutions in the embodiments of the present invention or the prior art. It should be understood that the accompanying drawings described below are only for the purpose of clearly illustrating some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of one embodiment of the overvoltage protection system provided by the present invention;

[0035] Figure 2 This is a schematic diagram of one embodiment of the overvoltage protection system provided by the present invention;

[0036] Figure 3 This is a circuit connection diagram of one embodiment of the overvoltage protection system provided by the present invention. Detailed Implementation

[0037] The embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. The step numbers in the following embodiments are set only for ease of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0038] First, the terms used in this application will be explained:

[0039] Switching power supply: A high-frequency power conversion device that can convert AC or DC power, such as mains power, into stable DC power.

[0040] A rectifier bridge is an electronic component that converts alternating current (AC) to direct current (DC). It consists of four diodes connected in a bridge circuit. During operation, utilizing the forward conduction and reverse cutoff characteristics of diodes, two diodes conduct during the positive half-cycle of the AC current, allowing current to flow through a specific path and output a positive voltage. During the negative half-cycle, the other two diodes conduct, outputting a negative voltage, thus converting AC to DC and ensuring that the current flows in only one direction.

[0041] RC step-down circuit: A circuit that uses resistors and capacitors to reduce voltage. Its principle is based on the capacitive reactance generated by a capacitor under alternating current. This capacitive reactance limits the current, thus reducing the voltage.

[0042] Overvoltage: The input voltage is too high.

[0043] A switching power supply is a widely used power converter in electronic devices, used to convert alternating current (AC) into stable direct current (DC) for power supply. Its technological background stems primarily from the demand for efficient, portable, and stable power supplies, which achieves power conversion through the on / off control of switching transistors. Currently, switching power supplies are characterized by high efficiency, small size, light weight, and high reliability. Compared to traditional linear power supplies, switching power supplies are more efficient and can provide high power output in a compact and lightweight form factor. Therefore, switching power supplies are widely used in many applications requiring stable voltage input.

[0044] Overvoltage protection circuits in switching power supplies are one of the core technologies for ensuring power supply safety and reliability. As electronic devices increasingly demand higher power stability, overvoltage protection needs to respond quickly to abnormal input voltages or sudden load changes to prevent damage to power devices (such as IGBTs and MOSFETs) and downstream circuits due to excessive voltage. Traditional solutions are mostly based on voltage divider sampling and voltage comparators, such as using comparators like the LM339 to monitor input or output voltage. When the detected value exceeds a preset threshold, protection is achieved by blocking the PWM drive signal or cutting off the main circuit. However, such methods have limitations in response speed and anti-interference capability, potentially leading to delayed protection. This application uses a resistor-capacitor step-down circuit to convert the high-voltage AC input into a stable DC voltage, offering advantages such as small size and low cost. Compared to traditional comparison methods, it is also less prone to chip damage due to excessive input voltage.

[0045] The overvoltage protection system and method proposed according to embodiments of the present invention will now be described in detail with reference to the accompanying drawings. First, an overvoltage protection system proposed according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0046] Figure 1 This is a schematic diagram of an overvoltage protection system according to an embodiment of the present invention. The system specifically includes:

[0047] The module consists of a step-down module, a voltage divider module, a comparator module, and a control module.

[0048] The mains power is connected to the voltage divider module through the step-down module. The voltage divider module is connected to the control module through the comparator module. The step-down module is also connected to the comparator module. The control module is connected to the target object.

[0049] The step-down module is used to reduce the mains voltage to obtain a first voltage, wherein the first voltage is the input voltage of the voltage divider module, the power supply voltage of the comparator module, and the drive voltage of the control module;

[0050] The voltage divider module is used to divide the first voltage to obtain the second voltage and the reference voltage;

[0051] The comparison module is used to obtain a drive signal based on the second voltage and the reference voltage; the drive signal is used to drive the relay of the control module to disconnect the power supply between the mains power and the target object.

[0052] The step-down module in this application includes a rectifier bridge and a resistor-capacitor unit. The second voltage in this application is related to the mains voltage; the second voltage is lower than the mains voltage, and it reflects the magnitude of the mains voltage. When the second voltage is greater than the reference voltage, the power supply between the mains and the target object is disconnected. This application is applicable to any application scenario that requires mains or AC input.

[0053] Furthermore, in the overvoltage protection system of this embodiment, the voltage divider module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and an adjustable Zener diode;

[0054] The first terminal of the first resistor is connected to the first voltage output terminal of the step-down module, and the second terminal of the first resistor is grounded. The first terminal of the second resistor is connected to the first terminal of the first resistor, and the second terminal of the second resistor is grounded through the third resistor. The second terminal of the second resistor is used to output the second voltage. The first terminal of the fourth resistor is connected to the first terminal of the first resistor, and the second terminal of the fourth resistor is connected to the first terminal of the fifth resistor. The second terminal of the fifth resistor is grounded through the sixth resistor. The anode of the adjustable Zener diode is grounded, the cathode of the adjustable Zener diode is connected to the second terminal of the fourth resistor, and the reference electrode of the adjustable Zener diode is connected to the second terminal of the fifth resistor. The cathode of the adjustable Zener diode is used to generate a reference voltage.

[0055] Furthermore, in one embodiment of the present invention, the voltage divider module further includes: a first Zener diode, the anode of the first Zener diode being connected to the first terminal of the first resistor, the cathode of the first Zener diode being grounded, and the first Zener diode being used to limit the first voltage.

[0056] In this application, the first voltage output terminal of the step-down module is one end of the rectifier bridge, the reference voltage output terminal of the voltage divider module is the anode of the adjustable Zener diode, and the second voltage output terminal of the voltage divider module is the second end of the second resistor.

[0057] Furthermore, in one embodiment of the present invention, the comparison module includes: a first comparator, the reference voltage output terminal of the voltage divider module is connected to the non-inverting input terminal of the first comparator, the second voltage output terminal of the voltage divider module is connected to the inverting input terminal of the first comparator, and the output terminal of the first comparator is used to output a relay drive signal.

[0058] Furthermore, in one embodiment of the present invention, the comparison module further includes: a second comparator, wherein the reference voltage output terminal is connected to the non-inverting input terminal of the second comparator, the output terminal of the first comparator is connected to the inverting input terminal of the second comparator, and the output terminal of the second comparator is connected to the first voltage output terminal of the buck module through a seventh resistor.

[0059] Furthermore, in one embodiment of the present invention, the control module includes a transistor, the output terminal of the first comparator is connected to the base of the transistor, the emitter of the transistor is connected to the first voltage output terminal, the collector of the transistor is connected to the coil of the relay, one end of the normally closed switch of the relay is connected to the mains power, and the other end of the normally closed switch is connected to the target object.

[0060] Furthermore, in one embodiment of the present invention, the difference between the resistance of the coil and the resistance of the seventh resistor is less than or equal to a preset difference.

[0061] On the other hand, embodiments of the present invention propose an overvoltage protection method applied to the aforementioned overvoltage protection system. This invention provides an overvoltage protection method that can be applied to a terminal, a server, or software running on a terminal or server. The terminal can be a tablet computer, a laptop computer, a desktop computer, etc., but is not limited to these. The server can be an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The method includes:

[0062] The mains power is stepped down to obtain the first voltage;

[0063] Divide the first voltage to obtain the second voltage and the reference voltage;

[0064] Based on the second voltage and the reference voltage, a drive signal is obtained; the drive signal is used to drive the relay of the control module to disconnect the power supply between the mains power and the target object.

[0065] Furthermore, the overvoltage protection method of this embodiment of the invention further includes:

[0066] The first value is determined based on the ratio of the mains voltage to the capacitance value of the step-down module;

[0067] The first voltage is determined by the product of the first value and the parallel resistance; the parallel resistance is related to the first, second, third, and fourth resistors of the voltage divider module and the seventh resistor of the comparator module.

[0068] The second voltage is determined based on the voltage division of the first voltage by the third resistor in the series branch of the second and third resistors.

[0069] Furthermore, the overvoltage protection method of this embodiment of the invention further includes:

[0070] Adjust the capacitance value, the first resistor, the second resistor, the third resistor, the fourth resistor, and the seventh resistor to determine the overvoltage protection threshold for generating the drive signal;

[0071] Alternatively, adjust the adjustable Zener diode to determine the overvoltage protection threshold for generating the drive signal.

[0072] The overvoltage protection system and overvoltage method of this application will be described in detail below with specific embodiments:

[0073] To address the aforementioned deficiencies in the prior art, this invention provides an input overvoltage protection circuit for a switching power supply. The input overvoltage protection circuit for the switching power supply is composed as follows: Figure 1 As shown, it includes: a resistor-capacitor (RC) step-down circuit (i.e., a step-down module), a voltage divider circuit (i.e., a voltage divider module), a comparator circuit (i.e., a comparator module), and a relay control circuit (i.e., a control module). The RC step-down circuit is connected to the voltage divider circuit, the voltage divider circuit is connected to the comparator circuit, and the comparator circuit is connected to the relay control circuit.

[0074] The working principle block diagram of the input overvoltage protection circuit of the switching power supply is as follows: Figure 2 As shown, the AC input of the switching power supply is connected to a resistor-capacitor step-down circuit to obtain a stepped-down voltage VCC (i.e., the first voltage), which serves as the input to the voltage divider circuit, the power supply for the comparator chip in the comparator circuit, and the drive voltage for the relay control circuit. The voltage divider circuit further divides VCC to obtain a comparison voltage Vcmp (i.e., the second voltage) and a reference voltage of 5V, which are used as the input to the comparator circuit. The comparator circuit compares the input comparison voltage Vcmp with the reference voltage +5V. Since the input voltage is stepped down to obtain the comparison voltage Vcmp, there is a linear relationship between the input voltage and the comparison voltage Vcmp. The overvoltage protection value can be set by adjusting the resistance value in the voltage divider circuit. When Vcmp exceeds +5V, it is considered an input overvoltage. The comparator circuit outputs a relay drive signal to the relay control circuit, continuously driving the relay to engage, causing the normally closed contact to open, thereby disconnecting the AC input from the power supply circuit of the switching power supply product and protecting the switching power supply product from overvoltage damage.

[0075] Implementation of input overvoltage protection circuit for switching power supply, for example Figure 3 As shown, it includes: a resistor-capacitor step-down circuit (1), a voltage divider circuit (2), a comparator circuit (3), and a relay control circuit (4). The external network connection includes: the mains input live wire (L) and the mains input neutral wire (N).

[0076] In the RC step-down circuit, the AC input live wire (L) is converted into pulsating DC power by a rectifier bridge composed of diodes D1, D2, D4, and D5. The specific working process is as follows:

[0077] Positive half-cycle: The current path is L→D2→load→D4→step-down capacitor C4→N.

[0078] Negative half-cycle: The current path is N→D5→load→D1→step-down capacitor C4→L. The pulsed DC current passes through the filter capacitor C1 to obtain a stable DC voltage (VCC). The step-down capacitor C4 utilizes its capacitive reactance to limit the AC current and undertakes the main voltage reduction task. In this embodiment, the capacitance of the step-down capacitor C4 is 0.8uF, and the formula for capacitive reactance is as follows:

[0079]

[0080] Where f is the frequency of the mains input, and C is the capacitance of the step-down capacitor C4. According to the formula, Xc≈3979Ω.

[0081] The step-down capacitor C4 limits the maximum AC current of the entire circuit. The current calculation formula is as follows:

[0082]

[0083] Vin represents the effective value of the AC input voltage. Taking a 220VAC AC input voltage, after full-bridge rectification, the average DC current is approximately 0.9 times the effective AC value.

[0084] I avg =0.9I rms

[0085] According to the formula, Iavg = 49.76mA.

[0086] The bleeder resistor R10 provides a discharge circuit for the step-down capacitor C4 after power is cut off, thus avoiding the risk of electric shock.

[0087] In the voltage divider circuit, the +5V voltage is provided by the adjustable voltage regulator U1 (i.e., the adjustable Zener diode). In this embodiment, the adjustable voltage regulator U1 is a TL431. The resistance values ​​of resistors R5 (i.e., the fifth resistor) and R7 (i.e., the sixth resistor) are both 10KΩ. Since the dynamic impedance of the adjustable voltage regulator U1 is 0.2Ω (refer to the TL431 datasheet), it is equivalent to shorting resistors R5 and R7, and the resistance value here can be ignored. The voltage value of VCC is determined by the equivalent resistance Rx (i.e., the parallel resistance) of the series connection of resistors R1 (i.e., the fourth resistor), R3 (i.e., the second resistor), R8 (i.e., the third resistor), R6 (i.e., the seventh resistor), and R12 (i.e., the first resistor) and the average DC current Iavg. The resistors R1, R3, R8, R6, and R12 are all 1.5KΩ, 3KΩ, 1.2KΩ, 1.5KΩ, and 500Ω respectively. The equivalent resistance Rx after these resistors are connected in parallel is:

[0088]

[0089] According to the formula, Rx = 280Ω.

[0090] The voltage value of VCC can be determined by Ohm's law:

[0091] VCC = I avg ·R x

[0092] According to the formula, VCC = 13.9V.

[0093] VCC will serve as the power supply and drive voltage for the comparator circuit and the relay control circuit. As shown in the formula above, VCC increases with the input voltage Vin. To prevent excessively high VCC from damaging the comparator chip in the comparator circuit, a Zener diode D3 (the first Zener diode) is connected in parallel with VCC. In this embodiment, Zener diode D3 is a 27V Zener diode to ensure that subsequent circuits are not damaged due to excessively high VCC. VCC is divided by resistors R3 and R8 to obtain Vcmp, which is the voltage across resistor R8. Vcmp can be obtained according to the voltage divider formula:

[0094]

[0095] Combining the previous formula, we can obtain:

[0096]

[0097] Therefore, Vcmp is 3.97V, and there is a linear relationship between the input voltage Vin and the comparison voltage Vcmp. The voltage value of the comparison voltage Vcmp will increase as the input voltage Vin increases.

[0098] The comparator circuit mainly consists of two comparators, U1A (the second comparator) and U1B (the first comparator). In this embodiment, the comparator chip is LM293. The comparison voltage Vcmp serves as the inverting input of U1B, and +5V serves as the non-inverting input. Resistors R9 and R11 form the positive feedback network of the comparator. In this embodiment, the resistance of R9 is 100KΩ, and the resistance of R11 is 3KΩ. The output of U1B is connected to VCC via resistor R2 (i.e., the output of U1B is connected to VCC via pull-up resistor R2) and to the positive terminal of Zener diode D6 via resistor R4. The resistances of R2 and R4 are both 10KΩ. The output of U1B controls the activation of the relay; a low output level activates the relay, and a high output level deactivates it.

[0099] +5V is used as the non-inverting input of U1A, and the output of U1B is connected to the inverting input of U1A. The output of U1A is connected to VCC through resistor R6. When U1B outputs a high level (U1B output has a pull-up voltage VCC, the high-level voltage is approximately VCC), U1A outputs a low level, and resistor R6 is essentially connected in parallel to the load of VCC; when U1B is low, U1A outputs a high level, and resistor R6 is equivalent to breaking the circuit. The resistance value of resistor R6 needs to match the impedance of the relay coil to avoid voltage fluctuations in VCC caused by changes in the load when the relay is energized. In this embodiment, the resistance of resistor R6 is 1.5KΩ, the relay is an 892-1CC-C-DC12V, and the coil resistance is 1.44KΩ.

[0100] In the relay control circuit, the emitter of PNP transistor Q1 is connected to VCC, the base is connected to the negative terminal of Zener diode D6, and the collector is connected to the relay coil and the negative terminal of diode D7. The other end of the coil is connected to GND and the positive terminal of diode D7, with diode D7 providing a discharge circuit for the coil. The normally closed contact of the relay is connected to the mains power line and the live input terminal of the switching power supply. In this embodiment, Zener diode D6 is a 3.3V Zener diode, PNP transistor Q1 is an MMBT4403, and diode D7 is a US1M.

[0101] The working process of the input overvoltage protection circuit composed of the aforementioned resistor-capacitor step-down circuit, voltage divider circuit, comparator circuit, and relay control circuit is illustrated in the above-mentioned embodiment:

[0102] As shown in the comparator circuit, when Vcmp ≥ 5V (i.e., input voltage Vin ≥ 276VAC), comparator U1B outputs a low level. At this time, the base-emitter voltage Vbe of PNP transistor Q1 ≥ -0.95V, satisfying the conduction condition. Zener diode D6 breaks down, and resistor R4 limits the base current, allowing PNP transistor Q1 to conduct. When the relay coil voltage reaches the pull-in voltage, the relay pulls in, and the normally closed contact opens, cutting off the live wire input of the switching power supply. This protects the internal components of the switching power supply from damage due to high voltage. In practical applications, the input overvoltage threshold (i.e., overvoltage protection threshold) can be adjusted by changing Vcmp or the +5V reference voltage as needed. Zener diode D6 is selected as a 3.3V Zener diode to prevent mis-conduction of the transistor, avoiding interference at the output of U1B that could cause mis-conduction of transistor Q1.

[0103] In one embodiment, the present invention provides an input overvoltage protection circuit for use in switching power supplies, which can prevent damage to the switching power supply due to accidental connection of high voltage during use. The overvoltage protection threshold of the input overvoltage protection circuit can be adjusted according to actual needs, and the circuit can be integrated into the switching power supply. It also uses common and inexpensive components, including transistors, Zener diodes, and relays, achieving the required functionality at a low cost while maintaining stable performance.

[0104] It is evident that the content of the above system embodiments is applicable to this method embodiment. The specific functions implemented in this method embodiment are the same as those in the above system embodiments, and the beneficial effects achieved are also the same as those achieved in the above system embodiments.

[0105] On the other hand, embodiments of the present invention provide an overvoltage protection device, comprising:

[0106] At least one processor;

[0107] At least one memory for storing at least one program;

[0108] When the at least one program is executed by the at least one processor, the at least one processor implements the overvoltage protection method.

[0109] Similarly, the content of the above method embodiments is applicable to this device embodiment. The specific functions implemented by this device embodiment are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0110] This invention also provides a computer-readable storage medium storing a processor-executable program, which, when executed by a processor, performs the above-described overvoltage protection method.

[0111] Similarly, the content of the above method embodiments is applicable to this storage medium embodiment. The specific functions implemented in this storage medium embodiment are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0112] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this invention are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is altered and sub-operations described as part of a larger operation are executed independently.

[0113] Furthermore, although the invention has been described in the context of functional modules, it should be understood that, unless otherwise stated, one or more of the functions and / or features may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding the invention. Rather, given the properties, functions, and internal relationships of the various functional modules in the apparatus disclosed herein, the actual implementation of the module will be understood within the scope of conventional skill of an engineer. Therefore, those skilled in the art can implement the invention as set forth in the claims using ordinary techniques without excessive experimentation. It is also understood that the specific concepts disclosed are merely illustrative and not intended to limit the scope of the invention, which is determined by the full scope of the appended claims and their equivalents.

[0114] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several programs to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0115] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequential list of executable programs for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, a program execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can retrieve and execute a program from or in conjunction with such a program execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can mean any means that can contain, store, communicate, propagate, or transmit a program for use by or in conjunction with a program execution system, apparatus, or device.

[0116] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0117] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable program execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0118] In the foregoing description of this specification, references to terms such as "one embodiment," "another embodiment," or "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0119] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0120] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. An overvoltage protection system, characterized in that, The system includes: a step-down module, a voltage divider module, a comparison module, and a control module; The mains power is connected to the voltage divider module through the step-down module, the voltage divider module is connected to the control module through the comparison module, the step-down module is also connected to the comparison module, and the control module is connected to the target object; The step-down module is used to reduce the mains voltage to obtain a first voltage, wherein the first voltage is the input voltage of the voltage divider module, the power supply voltage of the comparator module, and the drive voltage of the control module; The voltage divider module is used to divide the first voltage to obtain a second voltage and a reference voltage; The comparison module is used to obtain a drive signal based on the second voltage and the reference voltage; the drive signal is used to drive the relay of the control module to disconnect the power supply between the mains power and the target object; The comparison module includes: a first comparator, the reference voltage output terminal of the voltage divider module is connected to the non-inverting input terminal of the first comparator, the second voltage output terminal of the voltage divider module is connected to the inverting input terminal of the first comparator, and the output terminal of the first comparator is used to output a relay drive signal; The comparison module further includes: a second comparator, wherein the reference voltage output terminal is connected to the non-inverting input terminal of the second comparator, the output terminal of the first comparator is connected to the inverting input terminal of the second comparator, and the output terminal of the second comparator is connected to the first voltage output terminal of the buck module through a seventh resistor.

2. The overvoltage protection system according to claim 1, characterized in that, The voltage divider module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and an adjustable Zener diode; The first terminal of the first resistor is connected to the first voltage output terminal of the step-down module, and the second terminal of the first resistor is grounded; the first terminal of the second resistor is connected to the first terminal of the first resistor, and the second terminal of the second resistor is grounded through the third resistor, and the second terminal of the second resistor is used to output the second voltage; the first terminal of the fourth resistor is connected to the first terminal of the first resistor, and the second terminal of the fourth resistor is connected to the first terminal of the fifth resistor, and the second terminal of the fifth resistor is grounded through the sixth resistor; the anode of the adjustable Zener diode is grounded, the cathode of the adjustable Zener diode is connected to the second terminal of the fourth resistor, and the reference electrode of the adjustable Zener diode is connected to the second terminal of the fifth resistor; the cathode of the adjustable Zener diode is used to generate the reference voltage.

3. The overvoltage protection system according to claim 2, characterized in that, The voltage divider module further includes: a first Zener diode, the cathode of which is connected to the first end of the first resistor, and the anode of which is grounded. The first Zener diode is used to limit the first voltage.

4. The overvoltage protection system according to claim 1, characterized in that, The control module includes a transistor. The output of the first comparator is connected to the base of the transistor, the emitter of the transistor is connected to the first voltage output terminal, the collector of the transistor is connected to the coil of the relay, one end of the normally closed switch of the relay is connected to the mains power, and the other end of the normally closed switch is connected to the target object.

5. The overvoltage protection system according to claim 4, characterized in that, The difference between the resistance of the coil and the resistance of the seventh resistor is less than or equal to a preset difference.

6. An overvoltage protection method, characterized in that, Applied to an overvoltage protection system as described in any one of claims 1 to 5, the method comprises: The mains power is stepped down to obtain the first voltage; Divide the first voltage to obtain the second voltage and the reference voltage; A drive signal is obtained based on the second voltage and the reference voltage; the drive signal is used to drive the relay of the control module to disconnect the power supply between the mains power and the target object.

7. The overvoltage protection method according to claim 6, characterized in that, The method further includes: The first value is determined based on the ratio of the mains voltage to the capacitance value of the step-down module; The first voltage is determined based on the product of the first value and the parallel resistance; the parallel resistance is related to the first, second, third, and fourth resistors of the voltage divider module and the seventh resistor of the comparator module. The second voltage is determined based on the voltage division of the first voltage by the third resistor in the series branch of the second resistor and the third resistor.

8. The overvoltage protection method according to claim 7, characterized in that, The method further includes: Adjust the capacitance value, the first resistor, the second resistor, the third resistor, the fourth resistor, and the seventh resistor to determine the overvoltage protection threshold for generating the drive signal; Alternatively, adjust the adjustable Zener diode to determine the overvoltage protection threshold for generating the drive signal.

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