Interference test circuit and interference detection device

Abstract

The utility model discloses an interference test circuit and an interference detection device, the interference test circuit comprises a power supply, a controller, a relay, an AC contactor and an interference coil, the power supply, the relay, the AC contactor and the interference coil form a loop, the power supply is used for providing AC electric energy, the controller is connected with the power supply through a zero cross detection circuit, and the controller is connected with the interference coil. The acquisition module is used for acquiring crest time and trough time of a power supply; the controller is further used for controlling the relay to be switched on or switched off at the wave crest moment and the wave trough moment, so that the alternating current contactor generates instantaneous induction potential, and then the interference coil generates interference signals under the instantaneous induction potential. According to the utility model, by generating the interference signal and simulating an interference scene, developers are helped to better understand and solve the possible interference problem in the tested equipment, and the anti-interference capability and reliability of the tested equipment are improved.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic compatibility testing, and in particular to an interference testing circuit and an interference detection device. Background Art

[0002] Anti-interference performance is a crucial factor in the design and development of electronic products. Since electronic products are subject to various interferences in practical applications, such as electromagnetic interference and radio frequency interference, these interferences may affect their normal operation or even cause malfunctions. To ensure the stability and reliability of electronic products, they must undergo thorough anti-interference testing. Therefore, a device or equipment that can generate interference signals is crucial for testing the anti-interference performance of electronic products. Summary of the Invention

[0003] The purpose of the utility model is to provide an interference test circuit and an interference detection device to realize the generation of interference signals and improve the anti-interference performance and reliability of the equipment through the anti-interference performance of the interference signal detection equipment.

[0004] The technical solutions provided by this utility model are as follows:

[0005] In a first aspect, the present invention provides an interference test circuit, comprising:

[0006] A power supply, a controller, a relay, an AC contactor and an interference coil, wherein the power supply, the relay, the AC contactor and the interference coil form a loop;

[0007] The power supply is used to provide AC power;

[0008] The controller is connected to the power supply through a zero-crossing detection circuit, and is used to obtain the peak moment and trough moment of the power supply; the controller is also used to control the relay to close or disconnect at the peak moment and trough moment, so that the AC contactor generates an instantaneous induced potential, and then the interference coil generates an interference signal under the instantaneous induced potential.

[0009] The above interference test circuit obtains the zero-crossing point detected by the zero-crossing detection circuit through the controller, and calculates the peak and trough moments of the power supply based on the zero-crossing point. The controller controls the relay to close or disconnect at the peak and trough moments, so that the AC contactor generates an instantaneous induced potential, and then the interference coil generates an interference signal, thereby realizing precise control of the timing of the occurrence of the interference signal, enhancing the strength of the interference signal, and improving the flexibility and reliability of the test.

[0010] In one embodiment, the interference testing circuit further includes:

[0011] The driving circuit is connected between the controller and the relay, and is used to receive the control signal from the controller and control the on and off of the relay.

[0012] In one embodiment, the driving circuit includes:

[0013] a first resistor and a first semiconductor switching element;

[0014] One end of the first resistor is connected to the controller, and the other end is connected to the first electrode of the first semiconductor switch element. The second electrode of the first semiconductor switch element is connected to the relay coil, and the third electrode of the first semiconductor switch element is grounded.

[0015] In one embodiment, the zero-crossing detection circuit includes:

[0016] a second resistor, a third resistor, a fourth resistor, and an optical coupler;

[0017] The first port of the optocoupler is connected to the live wire of the power supply via the second resistor in series, the second port of the optocoupler is connected to the neutral wire of the power supply via the third resistor in series, the third port of the optocoupler is connected to the controller via the fourth resistor in parallel, and the fourth port of the optocoupler is grounded.

[0018] In one embodiment, the interference testing circuit further includes:

[0019] A first step-down conversion circuit is connected between the controller and the power supply and is used to supply power to the relay.

[0020] In one embodiment, the first buck conversion circuit includes:

[0021] Common mode inductor, first capacitor, second capacitor, third capacitor, AC-DC converter chip;

[0022] The common-mode inductor is connected in series between the input and output ends of the power live wire and the power neutral wire. The output end of the common-mode inductor is connected to one end of the first capacitor. The other end of the first capacitor is connected to the input end of the AC-DC conversion chip. The output end of the AC-DC conversion chip is connected to the second capacitor and the third capacitor. One end of the third capacitor is connected to the controller, and the other end is grounded.

[0023] In one embodiment, the interference testing circuit further includes:

[0024] A second buck conversion circuit is connected between the controller and the first buck conversion circuit and is used to supply power to the controller.

[0025] In one embodiment, the second buck conversion circuit includes:

[0026] A second semiconductor switch element, a voltage divider circuit, an input capacitor circuit, a linear voltage regulator chip, and an output capacitor circuit;

[0027] The first electrode of the second semiconductor switch element is connected to the voltage divider circuit, the second electrode of the second semiconductor switch element is connected to the first step-down conversion circuit, the third electrode of the second semiconductor switch element is connected to the input capacitor circuit, the input capacitor circuit is connected to the input end of the linear voltage regulator chip, the output end of the linear voltage regulator chip is connected to the output capacitor circuit, and the output capacitor circuit is connected to the controller.

[0028] In one embodiment, the interference testing circuit further includes:

[0029] A button is connected to the controller and is used to receive user instructions and generate a button signal. The controller receives the button signal and controls the on and off of the relay through the button signal.

[0030] The interference test circuit provided by this utility model provides an additional human-machine interaction interface through integrated buttons, allowing users to directly control the status of the relay. This not only enhances the usability and functionality of the system, but also improves safety and flexibility.

[0031] In some embodiments, the present invention further provides an interference detection device, comprising the above-mentioned interference test circuit.

[0032] The utility model provides an interference test circuit, which has at least one of the following technical effects:

[0033] 1. The controller obtains the zero-crossing point detected by the zero-crossing detection circuit and calculates the peak and trough moments of the power supply based on the zero-crossing point. The controller controls the relay to close or disconnect at the peak and trough moments, causing the AC contactor to generate an instantaneous induced potential, thereby causing the interference coil to generate an interference signal. This achieves precise control of the timing of the interference signal, enhances the strength of the interference signal, and improves the flexibility and reliability of the test.

[0034] 2. The integrated button provides an additional human-machine interface, allowing users to directly control the status of the relay. This not only enhances the system's usability and functionality, but also improves safety and flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0036] Figure 1 This is a basic implementation block diagram of an interference test circuit of the utility model;

[0037] Figure 2 This is a circuit implementation block diagram of an interference test circuit of the utility model;

[0038] Figure 3 This is a circuit diagram of a controller for an interference test circuit of the utility model;

[0039] Figure 4 This is a circuit structure diagram of a driving circuit of an interference test circuit of the utility model;

[0040] Figure 5 This is a circuit structure diagram of a zero-crossing detection circuit of an interference test circuit of the utility model;

[0041] Figure 6 This is a circuit structure diagram of a first step-down conversion circuit of an interference test circuit of the utility model;

[0042] Figure 7 This is a circuit structure diagram of a second step-down conversion circuit of an interference test circuit of the utility model;

[0043] Figure 8 The utility model is a circuit structure diagram of a key of an interference test circuit.

[0044] Reference numerals: controller-100, relay-200, AC contactor-300, interference coil-400 and zero-crossing detection circuit-500. DETAILED DESCRIPTION

[0045] In the following description, specific details such as specific system structures and technologies are provided for illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obstructing the description of the present application with unnecessary details.

[0046] It will be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections.

[0047] It should be further understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0048] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific embodiments of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings and other embodiments can be obtained based on these drawings without inventive work.

[0050] Anti-interference performance is a crucial factor in the design and development of electronic products. Since electronic products are subject to various interferences in practical applications, such as electromagnetic interference and radio frequency interference, these interferences may affect their normal operation or even cause malfunctions. To ensure the stability and reliability of electronic products, they must undergo thorough anti-interference testing. Therefore, there is an urgent need for a device or equipment that can generate interference signals to test the product's anti-interference performance.

[0051] The interference detection device designed in the utility model controls the state of the contacts of the relay through a controller, so that the AC contactor generates an instantaneous induced potential, and then the interference coil generates an interference signal under the instantaneous induced potential, simulating a real interference scenario.

[0052] One embodiment of the present invention, as Figure 1 As shown, the utility model provides an interference test circuit, including a power supply, a controller 100, a relay 200, an AC contactor 300 and an interference coil 400, and a loop is formed between the power supply, the relay 200, the AC contactor 300 and the interference coil 400.

[0053] The power supply is used to provide AC power.

[0054] The controller 100 is connected to the power supply through the zero-crossing detection circuit 500, and is used to obtain the peak moment and trough moment of the power supply; the controller 100 is also used to control the relay 200 to close or disconnect at the peak moment and trough moment, so that the AC contactor 300 generates an instantaneous induced potential, and then the interference coil 400 generates an interference signal under the instantaneous induced potential.

[0055] Specifically, such as Figure 1 and Figure 4 As shown, the controller 100 in this application specifically corresponds to the MCU, and the AC power supply voltage is 220V. In the interference test circuit of this application, the AC power supply is connected to the MCU through the zero-crossing detection circuit 500, and the MCU is connected to the relay 200. A diode D1 is connected between the coil terminals 1 and 4 of the relay 200 to prevent the influence of back electromotive force. The common terminal 2 of the relay 200 is connected to the neutral line of the AC power supply, the contact terminal 3 of the relay 200 is connected to the input terminal 2 of the primary winding of the transformer T1, and the other input terminal 1 of the primary winding of the transformer T1 is connected to the live wire of the AC power supply. The output terminal 3 of the secondary winding of the transformer T1 is connected to the AC contactor coil port 1, and the output terminal 4 of the secondary winding of the transformer T1 is connected to the AC contactor coil port 2 through the interference coil. The MCU, relay, AC contactor, interference coil, transformer and AC power supply form a loop.

[0056] Among them, the AC power supply provides the required AC power to the transformer T1, and the transformer T1 converts the voltage of the AC power supply into the required voltage level. The zero-crossing detection circuit 500 detects the zero-crossing point of the converted AC power and transmits the signal to the MCU. The MCU receives the zero-crossing point and calculates the peak and trough moments of the AC power supply based on the zero-crossing point. The MCU sends a control signal at the peak and trough moments to control the relay 200 to switch its contact state: when the contact terminal 3 of the relay 200 is closed, the inductor coil of the AC contactor 300 is connected to the circuit and starts to be energized. At this time, the current passes through the coil and generates a magnetic field; when the contact terminal 3 of the relay 200 is disconnected, the current in the inductor coil suddenly decreases or is interrupted, and a strong induced electromotive force (back electromotive force) is generated in the inductor coil. The induced electromotive force acts on the interference coil 400, causing a changing electromagnetic field to be generated around the interference coil 400, and then generating an interference signal. The interference signal is used to simulate a real electromagnetic interference environment. Through electromagnetic interference testing, potential electromagnetic compatibility problems can be discovered and solved in a timely manner, thereby improving the overall quality of the product.

[0057] In one embodiment, Figure 2 As shown, the interference test circuit further includes a driving circuit connected between the controller 100 and the relay 200 , for receiving a control signal from the controller 100 and controlling the on and off of the relay 200 .

[0058] Specifically, the controller 100 sends a high-level output signal to the drive circuit. The drive circuit receives the high-level output signal and converts it into a high-current, high-voltage signal capable of driving the relay 200, thereby controlling the relay 200 to switch its contact state. Integrating the drive circuit between the controller 100 and the relay 200 enables the controller 100 to effectively control the relay 200.

[0059] In one embodiment, Figure 3 and Figure 4 As shown, the driving circuit includes: a first resistor R8 and a first semiconductor switch element; one end of the first resistor R8 is connected to the controller 100, and the other end is connected to the first electrode of the first semiconductor switch element, the second electrode of the first semiconductor switch element is connected to the relay coil, and the third electrode of the first semiconductor switch element is grounded.

[0060] Specifically, in this solution, the first semiconductor switching element corresponds to the transistor Q2, which is used to amplify the control signal of the MCU and also to reduce the direct electrical connection between the MCU and the relay coil. The first electrode of the first semiconductor switching element corresponds to the base of the transistor Q2, the second electrode of the first semiconductor switching element corresponds to the collector of the transistor Q2, and the third electrode of the first semiconductor switching element corresponds to the emitter of the transistor Q2. The base of the transistor Q2 is connected to the RELAY pin of the MCU through the first resistor R8. The first resistor R8 is used to limit the current to prevent excessive current from directly entering the base of the transistor Q2. The collector of the transistor Q2 is connected to the relay coil end, and the emitter of the transistor Q2 is grounded.

[0061] Among them, the driving circuit receives the control signal of the MCU. When the MCU outputs a high-level signal, the current limited by the first resistor R8 enters the base of the transistor Q2, causing the transistor Q2 to be turned on. At this time, the collector and emitter of the transistor Q2 form a path, allowing current to pass through, and the relay coil obtains current; when the MCU outputs a low-level signal, there is not enough current to flow into the base of the transistor Q2, the transistor Q2 is cut off, the collector and emitter of the transistor Q2 are disconnected, and the current in the relay coil is interrupted.

[0062] By integrating the driving circuit, the control signal of the MCU is amplified so that it can drive the relay 200, while improving the control capability and electrical isolation of the circuit for high-power loads.

[0063] In another embodiment of the present invention, based on any of the above embodiments, the first semiconductor switching element is composed of other switching elements that can also provide sufficient current and voltage to achieve the effect of driving the relay. For example, MOS transistors, BJTs, IGBTs, etc. are not limited in this utility model. Of course, the use of other types of semiconductor switching elements as an alternative solution to the present invention is also within the scope of protection of this application.

[0064] In one embodiment, Figure 5 As shown, the zero-crossing detection circuit 500 includes: a second resistor R5, a third resistor R6, a fourth resistor R4, and an optocoupler; the first port of the optocoupler is connected to the live wire of the power supply through the second resistor R5 in series, the second port of the optocoupler is connected to the neutral wire of the power supply through the third resistor R6 in series, the third port of the optocoupler is connected to the controller 100 through the fourth resistor R4 in parallel, and the fourth port of the optocoupler is grounded.

[0065] Specifically, in this solution, the optical coupler U5 of the zero-crossing detection circuit 500 is composed of a light-emitting diode and a phototransistor, which is used to isolate the AC power supply and the MCU, and is also used to detect the zero-crossing point of the AC power supply. The positive electrode of the light-emitting diode is connected to the live wire of the 220V AC power supply through the second resistor R5, and the negative electrode of the light-emitting diode is connected to the neutral wire of the 220V AC power supply through the resistor R6. The collector of the phototransistor is connected to the PA1 pin of the MCU through the fourth resistor R4 in parallel, and the emitter of the phototransistor is grounded. The light-emitting diode is used to convert the voltage signal of the 220V AC power supply into an optical signal. The second resistor R5 and the third resistor R6 are used to For current limiting and voltage division, the phototransistor is used to receive the light signal from the light-emitting diode and convert it into an electrical signal. When the AC power supply voltage rises, the light-emitting diode emits light, the phototransistor is turned on, the collector voltage of the phototransistor decreases, and a low-level signal is output through the fourth resistor R4; when the 220V AC power supply voltage drops to zero, the light-emitting diode goes out, the phototransistor is cut off, the collector voltage of the phototransistor increases, and a high-level signal is output through the fourth resistor R4. By capturing the low-level and high-level signals, the MCU can determine the zero-crossing point of the AC power supply voltage and calculate the peak and trough moments of the AC power supply voltage.

[0066] In one embodiment, Figure 2 As shown, the interference detection circuit also includes a first step-down conversion circuit, which is connected between the controller 100 and the power supply to convert the 220V AC power supply voltage into a 12V DC power supply voltage for powering the relay 200. Through voltage conversion, electronic equipment that originally could only use a specific voltage can be connected to a wider power supply environment, thereby improving the compatibility and flexibility of the equipment.

[0067] In one embodiment, Figure 6 As shown, the first step-down conversion circuit includes: a first capacitor C5, a second capacitor C6, a third capacitor C7, and a conversion chip.

[0068] The common-mode inductor U2 is connected between the input and output ends of the live wire and neutral wire of the power supply and is used for EMI filtering. At the same time, the common-mode inductor U2 is connected in parallel with the varistor R2. The varistor R2 is used to clamp the voltage when the circuit is subjected to overvoltage and absorb excess current to protect sensitive devices. One end of the varistor R2 is connected to the P1 port through a fuse. The fuse is used to protect the circuit from damage when overcurrent or short circuit occurs in the circuit. The other end of the varistor R2 is connected to the P2 port. The common-mode inductor U2 is connected to one end of the first capacitor C5. The first capacitor C5 is used to smooth the rectified DC power and remove ripples and fluctuations in the voltage. The other end of the first capacitor C5 is connected to the input end of the AC-DC conversion chip. The output end of the AC-DC conversion chip is connected to the second capacitor C6 and the third capacitor C7. The second capacitor C6 and the third capacitor C7 are used to further smooth the output voltage. One end of the third capacitor C7 is connected to the controller 100 and the other end is grounded.

[0069] Specifically, common-mode inductor U2 receives AC power and serves as the input of the entire circuit. Varistor R2 is connected in parallel to common-mode inductor U2 to adjust the voltage passing through common-mode inductor U2. Common-mode inductor U2 inputs the filtered 220V AC voltage into the AC-DC converter chip, which converts the AC voltage into a 12V DC voltage. The AC-DC converter chip receives the DC voltage filtered by the first capacitor C5 and performs further processing and voltage stabilization through its internal circuit to ensure that the output voltage remains stable at 12V. The second capacitor C6 and the third capacitor C7 further smooth the output voltage. Finally, the stable 12V DC voltage is output through the controller 100 and supplied to the subsequent circuits. The coordinated operation of common-mode inductor U2 and the AC-DC converter chip achieves the conversion of high-voltage AC power to low-voltage DC power, providing a stable output voltage for the subsequent circuits.

[0070] In one embodiment, Figure 2 As shown, the interference detection circuit further includes a second step-down conversion circuit, which is connected between the controller 100 and the first step-down conversion circuit and is used to supply power to the controller 100. By converting the 12V DC power supply voltage into a 5V DC power supply voltage, efficient voltage conversion and stable voltage output are achieved, noise and interference in the circuit are reduced, and the stability and reliability of the entire system are improved.

[0071] In one embodiment, Figure 7As shown, the second step-down conversion circuit includes a second semiconductor switching element, a voltage divider circuit, an input capacitor circuit, a linear voltage regulator chip, and an output capacitor circuit; the first electrode of the second semiconductor switching element is connected to the voltage divider circuit, the second electrode of the second semiconductor switching element is connected to the first step-down conversion circuit, the third electrode of the second semiconductor switching element is connected to the input capacitor circuit, the input capacitor circuit is connected to the input end of the linear voltage regulator chip, the output end of the linear voltage regulator chip is connected to the output capacitor circuit, and the output capacitor circuit is connected to the controller.

[0072] Specifically, the second semiconductor switch element corresponds to the NMOS tube, the first electrode of the second semiconductor switch element corresponds to the gate of the NMOS tube, the second electrode of the second semiconductor switch element corresponds to the drain of the NMOS tube, and the third electrode of the second semiconductor switch element corresponds to the source of the NMOS tube.

[0073] Furthermore, the gate of the NMOS transistor is connected to a voltage divider circuit formed by resistors R1 and R3, causing the NMOS transistor to output a voltage of approximately 5V. The NMOS transistor is used to step down the voltage to prevent excessive voltage from flowing into the linear regulator U1. The source of the NMOS transistor is connected to the input of the linear voltage regulator chip via parallel capacitors C1 and C2. The output of the linear voltage regulator chip is connected to the controller via parallel capacitors C3 and C4. The linear voltage regulator chip is used to improve voltage conversion efficiency, and capacitors C1, C2, C3, and C4 are used to filter noise. This second step-down conversion circuit converts a 12V DC power supply into a 5V DC power supply, improving conversion efficiency and output voltage stability while reducing noise.

[0074] In another embodiment of the present invention, based on any of the above embodiments, the linear voltage regulator chip can be replaced with other components. For example, a DC-DC chip, etc., is not limited in this invention. Of course, using other types of voltage regulator chips as an alternative to the present invention is also within the scope of protection of this application.

[0075] In one embodiment, Figure 8 As shown, the interference test circuit also includes a button, which is connected to the controller 100 for receiving user instructions and generating a button signal. The controller 100 receives the button signal and controls the on and off of the relay 200 through the button signal.

[0076] Specifically, such as Figure 3 and Figure 8As shown, the buttons include a first button and a second button. The first button is connected to the PA3 pin of the MCU via the KEY1 pin. The KEY1 pin is grounded via a series resistor R12 and a key switch KEY1. The KEY1 pin is also connected to a 5V power supply via a resistor R10. The second button is connected to the PA4 pin of the MCU chip via the KEY2 pin. The KEY2 pin is grounded via a series resistor R13 and a key switch KEY2. The KEY2 pin is also connected to a 5V power supply via a resistor R11. The first and second buttons are used to turn on or off the power supply of the interference detection device and are also used to switch the operating mode of the relay. The relay operating modes include fast uniform mode, slow uniform mode, and random mode.

[0077] By pressing a button, the interference test circuit can be turned on or off, which is convenient for operation and maintenance. The relay working mode can also be switched to facilitate users to adjust the working status of the circuit according to their needs, making it easier for users to operate and control the interference test circuit, improving the convenience of use.

[0078] In another embodiment of the present invention, based on any of the above embodiments, the power supply can be of other voltage levels. For example, 380V, etc., which is not limited in the present invention. Of course, using other types of power supplies as an alternative to the present invention should also be within the scope of protection of this application.

[0079] In one embodiment, according to another aspect of the present invention, the present invention further provides an interference detection device, comprising the interference test circuit provided in the above embodiment.

[0080] In one embodiment, according to another aspect of the present invention, the present invention further provides an interference detection device, comprising the interference test circuit provided in the above embodiment.

[0081] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0082] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented with electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0083] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0084] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0085] It should be noted that the above embodiments can be freely combined as needed. The above are only preferred embodiments of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An interference test circuit, characterized in that: include: A power supply, a controller, a relay, an AC contactor and an interference coil, wherein the power supply, the relay, the AC contactor and the interference coil form a loop; The power supply is used to provide AC power; The controller is connected to the power supply through a zero-crossing detection circuit, and is used to obtain the peak moment and trough moment of the power supply; the controller is also used to control the relay to close or disconnect at the peak moment and trough moment, so that the AC contactor generates an instantaneous induced potential, and then the interference coil generates an interference signal under the instantaneous induced potential.

2. The interference test circuit according to claim 1, characterized in that: The interference test circuit further includes: The driving circuit is connected between the controller and the relay, and is used to receive the control signal from the controller and control the on and off of the relay.

3. The interference test circuit according to claim 2, characterized in that: The driving circuit includes: a first resistor and a first semiconductor switching element; One end of the first resistor is connected to the controller, and the other end is connected to the first electrode of the first semiconductor switch element. The second electrode of the first semiconductor switch element is connected to the relay coil, and the third electrode of the first semiconductor switch element is grounded.

4. The interference test circuit according to claim 1, characterized in that: The zero-crossing detection circuit comprises: a second resistor, a third resistor, a fourth resistor, and an optical coupler; The first port of the optocoupler is connected to the live wire of the power supply via the second resistor in series, the second port of the optocoupler is connected to the neutral wire of the power supply via the third resistor in series, the third port of the optocoupler is connected to the controller via the fourth resistor in parallel, and the fourth port of the optocoupler is grounded.

5. The interference test circuit according to claim 1, characterized in that: The interference test circuit further includes: A first step-down conversion circuit is connected between the controller and the power supply and is used to supply power to the relay.

6. The interference test circuit according to claim 5, characterized in that: The first step-down conversion circuit includes: Common mode inductor, first capacitor, second capacitor, third capacitor, AC-DC converter chip; The common-mode inductor is connected in series between the input and output ends of the power live wire and the power neutral wire. The output end of the common-mode inductor is connected to one end of the first capacitor. The other end of the first capacitor is connected to the input end of the AC-DC conversion chip. The output end of the AC-DC conversion chip is connected to the second capacitor and the third capacitor. One end of the third capacitor is connected to the controller, and the other end is grounded.

7. The interference test circuit according to claim 5 or 6, characterized in that: The interference test circuit further includes: A second buck conversion circuit is connected between the controller and the first buck conversion circuit and is used to supply power to the controller.

8. The interference test circuit according to claim 7, characterized in that: The second step-down conversion circuit includes: A second semiconductor switch element, a voltage divider circuit, an input capacitor circuit, a linear voltage regulator chip, and an output capacitor circuit; The first electrode of the second semiconductor switch element is connected to the voltage divider circuit, the second electrode of the second semiconductor switch element is connected to the first step-down conversion circuit, the third electrode of the second semiconductor switch element is connected to the input capacitor circuit, the input capacitor circuit is connected to the input end of the linear voltage regulator chip, the output end of the linear voltage regulator chip is connected to the output capacitor circuit, and the output capacitor circuit is connected to the controller.

9. The interference test circuit according to claim 1, characterized in that: The interference test circuit further includes: A button is connected to the controller and is used to receive user instructions and generate a button signal. The controller receives the button signal and controls the on and off of the relay through the button signal.

10. An interference detection device, characterized in that: The interference test circuit comprises any one of claims 1 to 9.

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