Electromagnetic interference precise injection device and method for loop-level immunity verification

Abstract

The present invention discloses an electromagnetic interference precise injection device and method for loop-level immunity verification, which is applicable to the immunity tests of power equipment, electronic equipment, etc. under various complex environments. The device consists of an electromagnetic interference signal generator, a handheld injection probe, an oscilloscope, a coaxial transmission line, etc. The probe structure adopts a double-cavity design, and the cavities of the interference coupling network and the attenuation network are separated by a central shielding partition. The shielding partition is filled with high-insulation silica gel to ensure that the cavities are independently isolated and have high-voltage protection performance. The device can generate various electromagnetic interference signals including surges, electrical fast transient pulse groups, damped oscillatory waves, etc., and precisely inject them into the internal loop of the device under test through a coaxial transmission line. The present invention is designed to be compact and flexible, applicable to the injection requirements of various electromagnetic interference signals, especially suitable for immunity verification under multi-stress environments, and has strong environmental adaptability and operation convenience.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system automation, and particularly relates to an electromagnetic interference precise injection device and method for loop-level immunity verification. Background Art

[0002] Existing electromagnetic immunity test methods mainly inject electromagnetic interference signals through the external ports of devices, and cannot accurately locate the electromagnetic sensitive points inside the devices. This method treats the device as a black box, ignoring the internal loop and hardware structure characteristics of the device, which limits the test accuracy. In addition, the structure of traditional injection devices is fixed and the operation is cumbersome, and it is impossible to achieve flexible handheld injection operation, let alone accurately inject into the sensitive points of the device under test; at the same time, there are delays and distortions in the waveform monitoring of the injected signal, and the injected waveform cannot be displayed in real time.

[0003] The patent application number is CN202123347273.8, named "An injection device for transient pulse interference". This patent is an injection device for transient pulse interference, and its system composition includes a pulse generator, a coupling network and an injection probe. The pulse generator emits electromagnetic interference signals; the coupling network is a capacitive coupling network, and the injection probe includes a 50Ω BNC connector, a double-layer shielded coaxial metal wire, and an alligator clip output terminal. Its principle is to simulate electromagnetic interference signals through a pulse signal generator, and transmit the signals to the injection probe without distortion through a capacitive coupling network, and finally inject them into each port of the device under test through the probe.

[0004] However, the existing technology has the following problems:

[0005] (1) It is impossible to accurately achieve loop-level injection of interference signals: Most electromagnetic immunity test methods can only inject interference signals through the external ports of devices, and it is difficult to accurately inject electromagnetic interference signals into specific internal loops of devices. This method can only evaluate the overall immunity of the device, and it is difficult to identify the electromagnetic sensitive points of each functional module inside the device. Especially in multi-layer PCB boards or complex circuit structures, the test accuracy is limited, resulting in an incomplete evaluation of the immunity of specific functional modules inside the device.

[0006] (2) Lack of immunity test under multi-stress environments: Traditional immunity test systems are limited by the scale of the test platform and usually can only simulate a single electromagnetic interference, and it is difficult to superimpose other environmental stresses (such as high and low temperature stresses), and it is impossible to test the immunity performance of devices in multi-stress environments such as high and low temperature chambers. This limitation makes the existing systems difficult to meet the actual working environment requirements of devices under complex stress superposition conditions, reducing the reference value and authenticity of the test results.

[0007] (3) Single probe design and inconvenient operation: The existing electromagnetic interference injection device is large in design volume and its structure is not flexible enough. The probe lacks miniaturization and handheld design, making it difficult to meet the requirements of fine operation. When conducting tests, operators have difficulty flexibly switching injection points in complex hardware circuits, and need to frequently switch different coupling networks or attenuation circuits during interference injection, which not only increases the operation difficulty, but also reduces the test efficiency and flexibility.

[0008] (4) Insufficient real-time signal acquisition and monitoring: The real-time monitoring and signal acquisition capabilities of traditional injection devices are relatively limited. Especially in a high-intensity electromagnetic interference environment, it is difficult to achieve real-time monitoring of waveforms, and signal acquisition is easily interfered and distorted. This defect makes it impossible to accurately record the instantaneous changes of the injected signal, increasing test errors and affecting the reliability of test results.

[0009] (5) Lack of modular design to meet multi-band coupling and attenuation requirements: The coupling network and attenuation module designs in existing injection systems are usually relatively simple and difficult to adapt to interference signals of different frequency bands. For scenarios that require multi-band switching in the same device, existing devices cannot flexibly adjust coupling and attenuation parameters, resulting in insufficient test responses when the device faces interference environments of different frequency bands and intensities, limiting the comprehensiveness of immunity verification.

[0010] (6) Insufficient high-voltage and high-current protection design: In existing test systems, many injection devices do not consider high-voltage resistance design, resulting in easy damage to equipment or introduction of additional interference when injecting high-voltage electromagnetic interference signals. In addition, existing equipment often lacks reliable electrical isolation and insulation protection in high-voltage and high-current environments, increasing safety risks and affecting the stability and accuracy of tests. Summary of the Invention

[0011] The purpose of the present invention is to provide an electromagnetic interference precise injection method and device for loop-level immunity verification in view of the above problems existing in the prior art.

[0012] On the one hand, a technical solution to achieve the purpose of the present invention is to provide an electromagnetic interference precise injection device for loop-level immunity verification, which includes a conducted interference signal source, a real-time monitoring module, and at least one handheld injection probe;

[0013] The conducted interference signal source is used to generate electromagnetic interference signals and transmit them to the handheld injection probe through a specific conduction path;

[0014] The handheld injection probe is used to inject interference signals into sensitive points of the hardware circuit of the device under test;

[0015] The real-time monitoring module is connected to the handheld injection probe and is used to monitor the waveform of the interference signal at the interference signal injection point in real time;

[0016] The device supports independent injection at multiple sensitive points. The handheld injection probe is used to inject interference signals at different sensitive points to achieve immunity verification at the loop level;

[0017] The real-time monitoring module supports multi-channel input to achieve synchronous monitoring of multiple sensitive points.

[0018] Furthermore, the conducted interference signal source is a combination of one or more electromagnetic interference signal generators, and supports separate injection or superimposed injection of various electromagnetic interference signals.

[0019] Furthermore, the handheld injection probe adopts a double-cavity design, including an interference injection cavity and a signal acquisition cavity. The two cavities are isolated by a shielding partition to form an independent cavity structure. Among them, the interference injection cavity is used to inject electromagnetic interference signals into the sensitive points of the hardware loop; the signal acquisition cavity is used to collect the interference signals at the sensitive points of the hardware loop and transmit the collected signals to the real-time monitoring module.

[0020] Furthermore, the interference injection cavity is provided with n coupling network modules and a first switching unit. By switching different coupling network modules through the first switching unit, that is, adjusting the gear of the coupling network, the transmission requirements of electromagnetic interference signals in different frequency bands can be met;

[0021] The signal acquisition cavity is provided with a plurality of attenuation network modules with different attenuation parameters and a second switching unit. By switching different attenuation network modules through the second switching unit, that is, adjusting the gear of the attenuation network module, multi-stage attenuation adjustment of the acquired electromagnetic interference signals can be achieved to ensure the stability during the signal acquisition process.

[0022] Furthermore, the coupling network module and the attenuation network module are respectively arranged on two PCBs installed on both sides of the shielding partition. The vertical projections of the two PCBs on the shielding partition do not overlap and maintain a certain distance.

[0023] Furthermore, the coupling network modules are all RC coupling networks. The first switching unit includes a magnetically controlled switch controlled by a sliding magnet, that is, a sliding magnetically controlled switch, and a reed switch. The second switching unit includes a mechanical sliding switch. The magnetically controlled switch and the mechanical sliding switch are both arranged on the outer surface of the handheld injection probe.

[0024] Further, the handheld injection probe has a pen-shaped structure and includes a housing. A shielding partition is disposed in the center of the housing along its axial direction to divide the internal space of the housing into two parts, forming the double-cavity structure;

[0025] One end face of the housing along its axial direction is divided into two isolated regions, which are respectively in communication with the interference injection cavity and the signal acquisition cavity, and can both contact the sensitive points of the hardware circuit. They serve as the interference signal injection window of the interference injection cavity and the signal detection window of the signal acquisition cavity respectively;

[0026] The interference signal injection window and the signal detection window of the signal acquisition cavity are respectively connected to the PCB through spring pins.

[0027] Further, a clamping and fixing device is provided at the other end of the housing along its axial direction for mounting the handheld injection probe on different platforms.

[0028] Further, the handheld injection probe adopts multi-layer internal and external shielding, specifically:

[0029] Inner layer shielding: Each cavity is filled with insulating silicone to wrap the circuit components, forming an inner layer shielding layer, and this inner layer shielding layer is grounded to the shielding partition;

[0030] Outer layer shielding: The handheld injection probe adopts a lightweight aluminum alloy material;

[0031] The space between the outer layer shielding and the inner layer shielding is filled with insulating silicone.

[0032] On the other hand, an electromagnetic interference precise injection method for loop-level immunity verification is provided. The method includes:

[0033] Generating an electromagnetic interference signal through a conducted interference signal source;

[0034] Injecting the electromagnetic interference signal into the sensitive points of the internal loop of the device under test through the handheld injection probe;

[0035] Switching different coupling network modules to meet different test requirements;

[0036] Switching different attenuation network modules to meet different test requirements;

[0037] Real-time monitoring the waveform of the electromagnetic interference signal at the injection point through a real-time monitoring module.

[0038] Compared with the prior art, the remarkable advantages of the present invention are:

[0039] (1)Precise interference signal loop-level injection: The handheld injection probe of the present invention can achieve precise injection of interference signals at multiple sensitive points of different functional modules through a dual-cavity design. Compared with the traditional external port injection method, this design enables the system to penetrate into specific circuits inside the device, accurately identify and evaluate the immunity of electromagnetic sensitive points, thereby significantly improving the accuracy and effectiveness of testing and meeting the refined testing requirements.

[0040] (2)Flexible signal attenuation and coupling network switching: The probe integrates multiple groups of switchable attenuation networks and coupling networks. Operators can switch between different signal paths and attenuation multiples through simple magnetic control switches or mechanical sliding switches, adapting to the requirements of interference signals with multiple frequencies and intensities, significantly improving the flexibility and efficiency of operation, and adapting to a variety of complex test environments.

[0041] (3)Efficient signal acquisition and real-time waveform monitoring: The signal acquisition module in the probe has high-efficiency real-time acquisition and transmission capabilities. It is connected to an oscilloscope located in a shielding box through a signal connector to achieve precise monitoring of the interference signal waveform. This design ensures the synchronization of injected and acquired signals, provides distortion-free waveform display, makes the test data more complete and accurate, and effectively avoids signal distortion problems in traditional tests.

[0042] (4)Superior electromagnetic interference resistance performance: The probe uses a lightweight aluminum alloy shell and combines high-insulation silica gel as a filling material to form a double electromagnetic shielding protection. The shielding partition further improves the electromagnetic isolation effect between the front and rear cavities, ensuring the stable operation of the probe in a high-interference environment and guaranteeing the reliability and anti-interference performance of signal transmission.

[0043] (5)Multi-stress environment adaptability: The present invention supports immunity tests in multi-stress environments. It can be placed in a high and low temperature test chamber to simulate the conditions of the superposition of temperature stress and electromagnetic interference, and conduct immunity verification closer to the actual working environment. Through comprehensive tests under multi-stress conditions, the system can comprehensively evaluate the immunity performance of the device and enhance the practical reference value of the test results.

[0044] (6)Modular and miniaturized design: The probe of the present invention adopts a dual-cavity parallel and modular structure, achieving a miniaturized design, which is convenient for flexible operation in complex hardware circuits. The probe has a simple switching function, supports rapid conversion of different coupling networks and attenuation networks, ensures rapid response and efficient adaptation under different test conditions, and thus improves the applicability of the system in diverse tests.

[0045] (7)The design of the present invention is compact and flexible, suitable for the injection requirements of various electromagnetic interference signals, especially suitable for immunity verification in multi-stress environments, and has strong environmental adaptability and operation convenience.

[0046] The present invention will be further described in detail below with reference to the accompanying drawings. Description of the Drawings

[0047] Figure 1 It is a schematic diagram of an electromagnetic interference precise injection device for loop-level immunity verification in an embodiment.

[0048] Figure 2 It is a schematic diagram of the structure of a handheld injection probe in an embodiment, where Figure 2 Figure (a) therein is a schematic diagram of the overall structure, Figure 2 Figure (b) therein is a partial schematic diagram of the interference injection cavity, Figure 2 Figure (c) therein is a partial schematic diagram of the signal acquisition cavity,

[0049] Figure 3 It is a left view of the handheld injection probe in an embodiment.

[0050] Figure 4 It is a top view of the handheld injection probe in an embodiment.

[0051] Figure 5 It is a schematic diagram of the internal circuit of the handheld injection probe in an embodiment.

[0052] Reference numerals: 1 - conducted interference signal source, 2 - handheld injection probe, 3 - real-time monitoring module, 4 - hardware loop, 5 - flexible coaxial cable, 6 - spring needle, 7 - end face, 8 - mechanical sliding switch, 9 - sliding magneto switch, 10 - shielding partition, 11 - signal connector, 12 - second flexible coaxial cable, 13 - first flexible coaxial cable, 14 - 10-fold attenuation circuit, 15 - 100-fold attenuation circuit, 16 - second PCB, 17 - RC coupling network, 18 - first PCB, 19 - second grounding point, 20 - first grounding point, 21 - reed switch. Detailed Embodiment

[0053] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0054] It should be noted that if there are directional indications (such as up, down, left, right, front, back,...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0055] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, such descriptions of "first", "second", etc. are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0056] In one embodiment, in combination with Figure 1 , an electromagnetic interference precise injection device for loop-level immunity verification is provided. The device includes a conducted interference signal source 1, a real-time monitoring module 3, and at least one handheld injection probe 2;

[0057] The conducted interference signal source is used to generate an electromagnetic interference signal and transmit it to the handheld injection probe 2 through a specific conduction path;

[0058] The handheld injection probe 2 is used to inject interference signals into the sensitive points of the hardware loop 4 of the device under test;

[0059] The real-time monitoring module 3 is connected to the handheld injection probe 2 and is used to monitor the waveform of the interference signal at the interference signal injection point in real time;

[0060] The device supports independent injection of multiple sensitive points. By injecting interference signals at different sensitive points through the handheld injection probe 2, loop-level immunity verification is achieved;

[0061] The real-time monitoring module 3 supports multi-channel input to synchronously monitor multiple sensitive points, ensuring the stability and accuracy of the interference signal transmission process, and also ensuring the accuracy of multi-point testing in a complex interference environment.

[0062] To enhance the environmental adaptability of the system, the entire device can be placed in a high and low temperature test chamber to simulate the conditions of temperature stress and electromagnetic interference superposition, so as to achieve immunity testing under multi-stress environments and comprehensively evaluate the anti-interference performance of the device in complex environments. Figure 1 The multiple sensitive points shown in

[0063] indicate that the system can perform precise interference injection and waveform acquisition at key positions inside the loop, thereby improving the accuracy of the test and the validity of the data.

[0064] Furthermore, in one of the embodiments, the conducted interference signal source is not limited to a combination of one or more electromagnetic interference signal generators, and supports separate injection or superposition injection of multiple electromagnetic interference signals.

[0065] Here, the electromagnetic interference signals include, but are not limited to, various signals or combinations thereof such as surges, electrical fast transient pulse groups, damped oscillatory wave signals, etc., to meet the electromagnetic interference test requirements of different types.

[0066] Preferably, in some embodiments, the conducted interference signal source is connected to the high-voltage terminal of the handheld injection probe through a calibrated characteristic impedance coaxial cable.

[0067] Furthermore, in one of the embodiments, in combination with Figures 2 to 4 , the handheld injection probe adopts a double-cavity design, including an interference injection cavity and a signal acquisition cavity, and the two cavities are isolated by a shielding partition 10 to form an independent cavity structure; wherein, the interference injection cavity is used to inject electromagnetic interference signals into the sensitive point of the hardware circuit 4; the signal acquisition cavity is used to collect the interference signals at the sensitive point of the hardware circuit 4 and transmit the collected signals to the real-time monitoring module 3.

[0068] Here, by setting the shielding partition 10, the influence of electromagnetic interference on signal transmission can be reduced, ensuring the signal stability of the two cavities.

[0069] Preferably here, the shielding partition is fixed in the middle position through a clamping structure to provide bidirectional support.

[0070] Preferably here, the signal transmission of the device of the present invention adopts a flexible coaxial cable, which is directly connected to the acquisition circuit to reduce signal loss and enhance the withstand voltage ability, ensuring signal integrity in a high-voltage environment.

[0071] Furthermore, in one of the embodiments, the interference injection cavity is provided with n coupling network modules and a first switching unit. By switching different coupling network modules through the first switching unit, that is, adjusting the gear of the coupling network, interference signals of different frequencies are coupled to the circuit under test to meet the transmission requirements of electromagnetic interference signals in different frequency bands, and further adapt to the signal injection requirements of different intensities, ensuring the flexibility of the test.

[0072] The signal acquisition cavity is provided with a plurality of attenuation network modules with different attenuation parameters and a second switching unit. By switching different attenuation network modules through the second switching unit, that is, adjusting the gear of the attenuation network module, multi-stage attenuation adjustment of the acquired electromagnetic interference signals is realized, and further the intensity of the acquired signals is adjusted to ensure the stability during the signal acquisition process.

[0073] Preferably, in some embodiments, the coupling network module and the attenuation network module are connected to a flexible coaxial cable through a signal connector 11. Specifically: the coupling network module is connected to a conducted interference signal source through a high-voltage-resistant signal connector and a first flexible coaxial cable 13, and the attenuation network module is connected to a real-time monitoring module 3 through a general signal connector and a second flexible coaxial cable 12. Among them, the flexible coaxial cable passes through a through hole at the tail end of the handheld injection probe and is respectively connected to the conducted interference signal source / real-time monitoring module 3.

[0074] Compared with the traditional connection method, this method using a high-voltage-resistant signal connector can ensure stable signal transmission while reducing contact resistance and potential electromagnetic interference.

[0075] Here, further preferably, a high-voltage insulation protection sleeve or coating is provided at the connection between the high-voltage-resistant signal connector and the central shielding partition to enhance the protection performance in a high-voltage environment and ensure the stability of signal transmission and the safety of the device.

[0076] It should be noted that using other connectors or high-voltage-resistant designs to achieve the same function also falls within the protection scope of the present invention.

[0077] Preferably, in some embodiments, the coupling network module and the attenuation network module are respectively arranged on two PCBs installed on both sides of the shielding partition, which are respectively denoted as the first PCB 18 and the second PCB 16; the vertical projections of the two PCBs on the shielding partition do not coincide and maintain a certain distance.

[0078] Here, the first grounding point 20 of the first PCB 18 and the second grounding point 19 of the second PCB 16 are led out from the handheld injection probe 2.

[0079] Here, further preferably, the grounding points on the two PCBs are led out through a detachable device installed on the handheld injection probe 2; the detachable device includes a flexible coaxial cable 5 and a detachable buckle. The flexible coaxial cable 5 is installed on the handheld injection probe 2 through the detachable buckle and is connected to the ground on the two PCBs through a through hole on the handheld injection probe 2. Here, the length of the flexible coaxial cable 5 is adjustable. Adopting the solution of this embodiment enables the device to be applicable to the grounding environment of any scenario.

[0080] Here, further preferably, the PCBs on both sides of the shielding partition are coated with aluminum foil, further improving the electromagnetic isolation effect between the two cavities and ensuring that the signal is not interfered during transmission.

[0081] Preferably, in some embodiments, in combination with Figure 5, the coupling network module employs, but is not limited to, the RC coupling network 17, which consists of multiple coupling capacitors (C1, C2, C3...) and series impedance resistors (R s1 、R s2 、R s3 ....).

[0082] Here, capacitors of different capacitances are applicable to signal transmission at different frequencies, enabling the coupling network to maintain good coupling performance at multiple frequencies. Each coupling capacitor is in series with a resistor of a specific resistance value to adjust the transmission impedance of the coupling network and ensure the impedance characteristics of the signal generator match the injection path.

[0083] Here, further preferably, the coupling capacitors are made of high-voltage-resistant ceramic capacitors, which can withstand the impact of high-voltage interference signals to ensure stability in a high-voltage environment; the series resistors are made of high-precision high-voltage-resistant metal film resistors to ensure stable impedance matching, thereby ensuring the stability and anti-interference ability of signal transmission. It should be noted that if other component materials with high-voltage-resistant performance are used to achieve the same function, they also fall within the protection scope of the present invention.

[0084] Preferably, in some embodiments, in combination with Figure 5 , the attenuation network module includes, but is not limited to, a multi-ratio adjustable attenuator, which can adjust the attenuation ratio according to actual needs to ensure signal stability.

[0085] Here, further preferably, the attenuation network module has, but is not limited to, two attenuation options: a 10-fold attenuation circuit 14 and a 100-fold attenuation circuit 15. The key components include a combination of resistors with different resistance values (R1 - R3, R6) and inductors (L0, L1).

[0086] Here, resistors with different resistance values are used to adjust the attenuation ratio of the signal to meet the signal strength requirements of different levels. The inductors cooperate with the attenuation resistor network to ensure impedance matching under high-frequency conditions and keep the signal stable during transmission.

[0087] Here, further preferably, the resistors in the attenuation network are made of high-voltage-resistant metal oxide film resistors, which can operate stably under high-voltage signal conditions, avoid signal distortion, and thus ensure the accuracy of signal acquisition.

[0088] Here, further preferably, the inductor material in the attenuation network is selected as ferrite with high magnetic permeability, which can effectively filter out high-frequency noise, maintain the purity of the signal, and ensure the stable transmission of the acquired signal.

[0089] Here, further preferably, around the key components and signal transmission paths of the attenuation network, a high-voltage resistant insulation coating is added, and a high-voltage resistant insulation sheath is provided at the connection interface to ensure electrical safety under high-voltage conditions and prevent signal interference caused by high-voltage leakage.

[0090] Preferably, in some embodiments, the first switching unit employs, but is not limited to, a magnetically controlled switch controlled by a sliding magnet, namely, a combination of a sliding magnetically controlled switch 9 and a reed switch 21, and the second switching unit employs, but is not limited to, a mechanical sliding switch 8.

[0091] Here, the sliding magnet controls the opening and closing state of the reed switch, thereby switching between different coupling circuits to meet different requirements for injecting interference signals. The attenuation levels of the attenuation network are switched by a mechanical sliding switch, and then different attenuation paths are selected to meet the signal adjustment requirements under different test conditions.

[0092] Here, further preferably, both the magnetically controlled switch and the mechanical sliding switch are provided on the outer surface of the handheld injection probe 2 for easy operation. The specific position is not limited, and it is preferably close to the corresponding cavity.

[0093] Here, further preferably, a high-voltage resistant sealed reed switch is selected for the reed switch, which can work safely in a high-voltage environment, and an insulating sleeve is added in the pin area to enhance insulation. The shielding layer of the reed switch is grounded to effectively isolate electromagnetic interference and ensure the stability of the high-voltage switching process.

[0094] Preferably, in some embodiments, the handheld injection probe has a pen-shaped structure, including a housing. A shielding partition is provided along the axial direction in the center of the housing to divide the internal space of the housing into two parts, forming the double-cavity structure.

[0095] Here, a miniaturized design with a pen-shaped structure is adopted, which is convenient to hold and enables the operator to accurately locate and switch the injection points in a compact and complex hardware circuit.

[0096] Here, further preferably, one end face 7 of the housing along its axial direction is divided into two mutually isolated regions, which are respectively in communication with the interference injection cavity and the signal acquisition cavity, and can both contact the sensitive points of the hardware circuit 4, serving as the interference signal injection window of the interference injection cavity and the signal detection window of the signal acquisition cavity respectively.

[0097] Here, further preferably, the interference signal injection window and the signal detection window are respectively connected to the PCB through spring pins 6. The spring pins 6 realize the signal transmission between the interference signal injection window, the signal detection window and their respective corresponding PCBs, and also play a role in installing and supporting between components.

[0098] Here, further preferably, the other end of the housing in its axial direction is provided with a clamping and fixing device for mounting the handheld injection probe on different platforms.

[0099] Here, further preferably, the housing is made of but not limited to lightweight aluminum alloy material, and the housing is provided with hollow holes to enhance the heat dissipation effect in a high-temperature test environment.

[0100] Furthermore, in one embodiment, the handheld injection probe adopts multi-layer internal and external shielding, specifically:

[0101] Inner layer shielding: Each cavity is filled with but not limited to insulating silica gel to wrap the circuit components, forming an inner layer shielding layer, and the inner layer shielding layer is grounded with the shielding partition;

[0102] Outer layer shielding: The handheld injection probe is made of lightweight aluminum alloy material;

[0103] The space between the outer layer shielding and the inner layer shielding is filled with insulating silica gel.

[0104] Furthermore, in one embodiment, the real-time monitoring module 3 is a shielded module.

[0105] Adopting the solution of this embodiment can work stably in an electromagnetic interference environment and ensure that signal transmission is not interfered by the outside world.

[0106] Here, the real-time monitoring module 3 is made of but not limited to an oscilloscope.

[0107] In one embodiment, an electromagnetic interference precise injection method for loop-level immunity verification based on the above device is provided, and the method includes:

[0108] Generating an electromagnetic interference signal through a conducted interference signal source;

[0109] Injecting the electromagnetic interference signal into the sensitive point of the internal loop of the device under test through the handheld injection probe;

[0110] Switching different coupling network modules to meet different test requirements;

[0111] Switching different attenuation network modules to meet different test requirements;

[0112] Real-time monitoring of the waveform of the electromagnetic interference signal at the injection point through the real-time monitoring module.

[0113] Furthermore, in one embodiment, the method further includes:

[0114] Placing the device and the device under test in a high and low temperature test chamber for multi-stress superposition testing to evaluate the immunity performance of the device in a complex environment.

[0115] If the same test function is implemented using other injection probe configurations or test environments, it also falls within the protection scope of the present invention.

[0116] In summary, the present invention can achieve:

[0117] (1) Achieve precise injection of interference signals at the circuit level: The present invention aims to provide an electromagnetic interference precise injection device and method that can penetrate into specific circuits inside the device. By designing a handheld injection probe, the electromagnetic interference signal is directly injected into the specified functional module inside the device to achieve signal interference injection at the circuit level. This design can identify the electromagnetic sensitive points inside the device, effectively evaluate the immunity of specific functional modules, improve the test accuracy and refinement degree, and ensure the pertinence and reliability of the test results.

[0118] (2) Support comprehensive immunity tests under multi-stress environments: Another object of the present invention is to provide a test system that can simulate other environmental stresses (such as high and low temperature stresses) in addition to electromagnetic interference tests. Combined with a high and low temperature test chamber, the device can test the immunity performance of the device in an environment with multi-stress superposition, enhancing the environmental simulation ability of the test, and thus more realistically reflecting the immunity performance of the device in the actual working environment.

[0119] (3) Improve the flexibility and operation convenience of the probe design: Through the miniaturization design of the handheld pen probe of the present invention, the operator can accurately locate and switch the injection point in a compact and complex hardware circuit. The probe has a fast switching function for multi-coupling networks and attenuation circuits, which is not only convenient for flexible testing at different frequencies and intensities, but also simplifies the operation process, improves the test efficiency and flexibility, and adapts to various test conditions.

[0120] (4) Enhance the real-time signal acquisition and monitoring ability: The present invention designs an oscilloscope placed inside a shielding box with a real-time waveform monitoring function, which can accurately acquire and display the signal waveform in a high-intensity electromagnetic interference environment to ensure that the instantaneous change of the injected signal is reflected without distortion. This real-time monitoring design improves the accuracy of the test record and the reliability of the result, ensuring that users can obtain high-quality immunity data.

[0121] (5) Achieve modular design of multi-band coupling and multi-magnification attenuation: The injection probe of the present invention is internally designed with a multi-band coupling network and a multi-magnification adjustable attenuation module, which can meet the requirements of interference signals at different frequencies and intensities. Through the modular design, users can flexibly select and switch the coupling and attenuation circuits according to the test requirements, improve the adaptability of the device to multi-band interference, and make it suitable for complex and changeable electromagnetic interference test scenarios.

[0122] (6) Enhanced high-voltage resistance and safety protection design: To meet the requirements of high-voltage electromagnetic interference injection, the present invention designs a high-voltage-resistant connector at the connection between the probe and the coaxial transmission line, and uses high-insulating materials and shielding structures inside the probe to ensure the safety of the equipment and the stability of signal transmission in a high-voltage environment. This protection design reduces the operation risk and effectively reduces the interference error that may be brought by high-voltage injection.

[0123] As a specific example, the present invention is further systematically analyzed and verified.

[0124] The present invention provides an electromagnetic interference precise injection device and method for verifying loop-level immunity. The structure and working principle of the device are as Figures 1 to 5 shown, mainly including components such as an electromagnetic interference signal generator, a handheld injection probe, an oscilloscope placed in a shielding box, a coaxial transmission line, a coupling network, and an attenuation network. Specifically, it includes:

[0125] (1) Structure of the electromagnetic conduction interference fault precise injection device

[0126] This device mainly includes modules such as an electromagnetic interference signal generator, a handheld injection probe, an oscilloscope placed in a shielding box, a coaxial transmission line, a coupling network, and an attenuation network. The electromagnetic interference signal generator generates interference signals with specific frequencies and intensities, which are transmitted to the handheld injection probe through the coaxial transmission line. The coupling network inside the probe precisely injects the interference signal into a specific loop inside the device, and the signal is transmitted to the oscilloscope placed in the shielding box after being adjusted by the attenuation network to ensure stable monitoring of the signal.

[0127] (2) Structure and function of the handheld injection probe

[0128] Two independent cavities are designed inside the handheld injection probe: the interference coupling cavity is used for the transmission of interference signals, and the signal attenuation cavity is used for signal acquisition and processing. A central shielding partition is set between the two cavities, and insulating silica gel is filled on both sides of the partition to ensure electrical insulation in a high-voltage environment and the independence of the cavity structure. The design of the probe enables it to accurately locate the injection point of the interference signal in a complex hardware loop and real-time acquire the response of the interference signal, supporting the requirements of multi-point testing and acquisition.

[0129] (3) Hardware loop structure

[0130] The hardware loop of the device under test includes multiple functional modules and sensitive points, and can realize immunity testing from the overall level to the chip pin level. The hardware loop supports multi-point interference signal injection and global scanning, and tests the immunity of each module under different interference conditions by precisely injecting interference signals and acquiring signals at key sensitive points inside the device.

[0131] (4) Dual-cavity structure design and housing material

[0132] The handheld injection probe adopts a dual-cavity parallel design. The central shielding partition is used to separate the interference coupling network and the attenuation network into two independent cavities, and high-insulation silica gel is filled around the partition to form an insulating structure with high voltage resistance and anti-interference. The shell is made of lightweight aluminum alloy material, and an aluminum foil shielding layer is added to the inner surface; the outside is covered with elastic rubber and a metal braid layer to form a multi-layer shielding protection, providing high-strength electromagnetic isolation and anti-impact protection.

[0133] (5)Coupling Network Design and Component Selection

[0134] The coupling network includes multiple coupling capacitors and resistors. The capacitors are selected as high-voltage-resistant ceramic capacitors (C1, C2, C3), and the resistors are selected as metal film resistors (R s1 , R s2 ), ensuring that signals can be transmitted safely and stably under high-voltage interference signal injection conditions. Each coupling loop realizes three-level switching through a magnetron switch and a reed switch to meet the transmission requirements of multi-band interference signals.

[0135] The specific component selection is as follows:

[0136] Coupling capacitors: High-voltage-resistant ceramic capacitors of 10pF, 20pF, and 47pF are used to adapt to the signal requirements of different frequency bands and ensure stability in a high-voltage environment.

[0137] Series resistors: High-precision metal film resistors of 100Ω and 200Ω are selected to ensure stable impedance matching and meet the requirements of different test conditions.

[0138] Switching different coupling paths is achieved through the combination of a reed switch and a magnetron switch. The built-in three-level and switching switch of the probe can flexibly adjust the signal path to meet the multi-band signal injection requirements. The reed switch component is selected as a high-voltage-tolerant model to ensure the safety and reliability of high-voltage signals.

[0139] (6)Attenuation Network (Backhaul Circuit) Design and Component Selection

[0140] The attenuation network is used to adjust the intensity of the backhaul signal, and two attenuation ratios of 10 times and 100 times are designed. The key components include high-voltage-resistant metal oxide film resistors (ensuring signal stability under high-voltage conditions) and high-frequency ferrite inductance L0. The backhaul circuit also adds a high-voltage-resistant insulation coating at key parts to ensure electrical insulation in a high-voltage environment. The specific component selection is as follows:

[0141] Attenuation resistors: The 10-fold attenuation and 100-fold attenuation gears are realized by 1MΩ and 10MΩ high-voltage-resistant metal oxide film resistors to ensure accurate signal attenuation.

[0142] High-frequency inductor: A high-permeability ferrite inductor is selected to filter out high-frequency noise and maintain signal purity.

[0143] Switching between different attenuation paths is achieved through a mechanical sliding switch. An internal two-position switch can be used to flexibly adjust the signal path to meet the injection requirements of signals with different intensities.

[0144] (7)Signal connector design and high-voltage protection

[0145] The hole and slot at the probe tail are hollowed out. The flexible coaxial cable is directly connected from the shielding partition to the external generator or oscilloscope, providing efficient signal transmission and reducing signal loss.

[0146] A signal connector is used for the connection between the PCB and the flexible cable. A high-voltage-resistant connector is used on the coupling network side, and a signal connector is used on the attenuation network side. The design of the connector involves a high-voltage insulation sheath and high-voltage-resistant filling materials to ensure safe connection under high-voltage conditions. A groove structure is also designed at the bottom of the probe to facilitate fixation with the auxiliary fixture and ensure stability in various environments such as a high and low temperature test chamber.

[0147] Application example: The process of the equipment loop-level electromagnetic interference immunity test

[0148] (1)Preparation of experimental equipment

[0149] Prepare an electromagnetic interference signal generator, a handheld injection probe, an oscilloscope placed in a shielding box, and a hardware loop. Check whether the connections of all equipment are complete, ensure that the coaxial transmission line is firmly connected, the signal generator is working properly, and the oscilloscope placed in the shielding box is in the real-time monitoring mode to observe the response of the interference signal.

[0150] (2)Setting of interference signal parameters

[0151] Select the type of interference signal (such as electrical fast transient pulse group or surge signal) on the electromagnetic interference signal generator, and set the appropriate frequency and amplitude. According to the test requirements, a single interference signal output or a multiple signal superposition mode can be selected to simulate the electromagnetic interference situation in the real working environment.

[0152] (3)Probe coupling network configuration

[0153] According to the requirements of the device test frequency band, different coupling capacitance values (such as 10 pF, 20 pF, 47 pF) are switched through the magnetic control switch of the handheld injection probe to achieve precise coupling of interference signals in different frequency bands. The combination of the reed switch and the magnetic control switch realizes the switching of different coupling paths to ensure effective coupling of signals in different frequency bands.

[0154] (4)Setting of signal attenuation ratio

[0155] Use the mechanical slide switch inside the probe to switch the attenuation ratio (such as 10 times or 100 times), and adjust the signal strength to adapt to the monitoring range of the oscilloscope placed in the shielding box. The high-voltage resistors and high-frequency inductors in the attenuation network ensure the stable transmission of signals under high-voltage and high-frequency conditions, preventing signal distortion.

[0156] (5) Connect and position the probe

[0157] Align the tip probe of the handheld injection probe with a specific sensitive point on the hardware loop of the device under test. Connect the ground wire interface to ensure electromagnetic compatibility during the test, and ensure that the probe is in a stable state before contacting the sensitive point for accurate signal injection.

[0158] (6) Interference signal injection

[0159] Start the electromagnetic interference signal generator, and transmit the signal to the handheld injection probe through a flexible coaxial cable. After the tip probe contacts the sensitive point of the device, the probe accurately injects the interference signal into the device loop to simulate the device response under real electromagnetic interference conditions.

[0160] (7) Real-time monitoring and recording

[0161] The handheld injection probe is connected to the oscilloscope placed in the shielding box to monitor the waveform of the interference signal at the sensitive point in real time. Record the response of the device during the interference injection process, including changes and distortions of the signal waveform, for subsequent analysis.

[0162] (8) Multi-point interference injection

[0163] To comprehensively evaluate the immunity of the device, point-by-point tests can be carried out at different sensitive points in the hardware loop. Inject the interference signal each time and monitor its response, repeating steps (3) to (7) to test the electromagnetic immunity of the device at different sensitive points.

[0164] (9) Multi-stress test

[0165] Place the hardware loop and the handheld injection probe in a high and low temperature test chamber, and superimpose temperature stress to simulate the working state of the device in extreme environments. The temperature range (such as -40°C to 85°C) and the superposition of electromagnetic interference signals simulate the immunity of the device in real environments. Repeat the interference injection and waveform monitoring, and record the response of the device under complex stress conditions.

[0166] (10) Analysis and evaluation

[0167] Analyze the test data of each sensitive point to evaluate the electromagnetic immunity of the device. Record the response data of the device under different conditions, including waveform distortion, device function changes, etc. Compare the performance of the device under different temperature and interference intensity conditions to comprehensively evaluate the adaptability and anti-interference ability of the device.

[0168] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An electromagnetic interference precise injection device for loop-level immunity verification, characterized in that The device includes a conducted interference signal source, a real-time monitoring module, and at least one handheld injection probe; The conducted interference signal source is used to generate electromagnetic interference signals and transmit them to the handheld injection probe through a specific conduction path; The handheld injection probe is used to inject interference signals into the sensitive points of the hardware circuit of the device under test; The real-time monitoring module is connected to the handheld injection probe and is used to monitor the waveform of the interference signal at the interference signal injection point in real time; The device supports independent injection of multiple sensitive points. The handheld injection probe injects interference signals at different sensitive points to achieve immunity verification at the circuit level; The real-time monitoring module supports multi-channel input to achieve synchronous monitoring of multiple sensitive points; The handheld injection probe adopts a double-cavity design, including an interference injection cavity and a signal acquisition cavity. The two cavities are isolated by a shielding partition to form an independent cavity structure. Among them, the interference injection cavity is used to inject electromagnetic interference signals into the sensitive points of the hardware circuit; the signal acquisition cavity is used to collect the interference signals at the sensitive points of the hardware circuit and transmit the collected signals to the real-time monitoring module; The interference injection cavity is provided with n coupling network modules and a first switching unit. By switching different coupling network modules through the first switching unit, that is, adjusting the gear of the coupling network, the transmission requirements of electromagnetic interference signals under different frequency bands can be met; The signal acquisition cavity is provided with a plurality of attenuation network modules with different attenuation parameters and a second switching unit. By switching different attenuation network modules through the second switching unit, that is, adjusting the gear of the attenuation network module, multi-level attenuation adjustment of the acquired electromagnetic interference signals can be achieved to ensure the stability during the signal acquisition process; The coupling network module and the attenuation network module are respectively arranged on two PCBs installed on both sides of the shielding partition. The vertical projections of the two PCBs on the shielding partition do not coincide and maintain a certain distance.

2. The electromagnetic interference precise injection device for loop-level immunity verification according to claim 1, characterized in that The conducted interference signal source is a combination of single or multiple electromagnetic interference signal generators, and supports separate injection or superimposed injection of multiple electromagnetic interference signals.

3. The electromagnetic interference precise injection device for loop-level immunity verification according to claim 1, characterized in that The coupling network module adopts an RC coupling network. The first switching unit includes a magnetically controlled switch controlled by a sliding magnet, that is, a sliding magnetically controlled switch, and a reed switch. The second switching unit includes a mechanical sliding switch. The sliding magnetically controlled switch and the mechanical sliding switch are both arranged on the outer surface of the handheld injection probe; 4. The electromagnetic interference precise injection device for loop-level immunity verification according to claim 1, wherein The handheld injection probe has a pen-shaped structure, including a housing. The shielding partition is arranged along the axial direction in the center of the housing to divide the internal space of the housing into two parts, forming the double-cavity structure; One end face of the housing along its axial direction is divided into two isolated regions, which are respectively in communication with the interference injection cavity and the signal acquisition cavity, and can both contact the sensitive points of the hardware circuit, serving as the interference signal injection window of the interference injection cavity and the signal detection window of the signal acquisition cavity respectively; The interference signal injection window and the signal detection window of the signal acquisition cavity are respectively connected to their corresponding PCBs through spring pins.

5. The electromagnetic interference precise injection device for loop-level immunity verification according to claim 4, wherein At the other end of the housing along its axial direction, there is a clamping and fixing device for mounting the handheld injection probe on different platforms.

6. The electromagnetic interference precise injection device for loop-level immunity verification according to claim 1, characterized in that The handheld injection probe adopts multi-layer internal and external shielding, specifically: Inner layer shielding: Each cavity is filled with insulating silicone to wrap the circuit components, forming an inner layer shielding layer, and this inner layer shielding layer is grounded with the shielding partition; Outer layer shielding: The handheld injection probe is made of lightweight aluminum alloy material; The space between the outer layer shielding and the inner layer shielding is filled with insulating silicone.

7. An electromagnetic interference precise injection method for loop-level immunity verification based on the device according to any one of claims 1 to 6, characterized in that, The method includes: Generating an electromagnetic interference signal through a conducted interference signal source; Injecting the electromagnetic interference signal into the sensitive point of the internal circuit of the device under test through the handheld injection probe; Switching different coupling network modules to meet different test requirements; Switching different attenuation network modules to meet different test requirements; Real-time monitoring the waveform of the electromagnetic interference signal at the injection point through a real-time monitoring module.

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