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

Abstract

The invention discloses an electromagnetic interference accurate injection device and an electromagnetic interference accurate injection method for loop-level immunity verification, which are suitable for immunity tests of power equipment, electronic equipment and the like in various complex environments. The device is composed of an electromagnetic interference signal generator, a handheld injection probe, an oscilloscope, a coaxial transmission line and the like. The probe structure adopts a double-cavity design, cavities of an interference coupling network and an attenuation network are separated through a central shielding partition plate, the shielding partition plate is filled with high-insulation silica gel, and it is ensured 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 trains, damped oscillation waves and the like, and accurately injects the electromagnetic interference signals into an internal loop of equipment to be tested through a coaxial transmission line. The device is compact and flexible in design, is suitable for injection requirements of various electromagnetic interference signals, is especially suitable for immunity verification in a multi-stress environment, and has relatively high environmental adaptability and operation convenience.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system automation, and in particular to an electromagnetic interference precision injection device and method for loop-level anti-interference verification. Background Art

[0002] The existing electromagnetic immunity test method mainly injects electromagnetic interference signals through the external port of the device, which cannot accurately locate the electromagnetic sensitive points of the internal circuit of the device. This method treats the device as a black box, ignores the internal circuit and hardware structure characteristics of the device, and limits the accuracy of the test. In addition, the traditional injection device has a fixed structure and cumbersome operation, and cannot achieve flexible handheld injection operation, let alone accurate injection of sensitive points of the device under test; at the same time, the waveform monitoring of the injection signal has delays and distortions, and the injection waveform cannot be displayed in real time.

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

[0004] However, the prior art has the following problems:

[0005] (1) It is impossible to accurately inject interference signals at the loop level: Most electromagnetic interference immunity test methods can only inject interference signals through the external port of the device, and it is difficult to accurately inject electromagnetic interference signals into the internal loop of a specific device. This method can only evaluate the overall immunity of the device, but 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 testing in multiple stress environments: Traditional immunity testing systems are limited by the scale of the test platform and can usually only simulate a single electromagnetic interference, but are difficult to superimpose with other environmental stresses (such as high and low temperature stresses), and cannot test the immunity performance of equipment in multiple stress environments such as high and low temperature boxes. This limitation makes it difficult for existing systems to meet the actual working environment requirements of equipment 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 size and inflexible in structure. The probe lacks miniaturization and handheld design, which makes it difficult to meet the needs of refined operation. It is difficult for operators to flexibly switch injection points in complex hardware loops during testing, and different coupling networks or attenuation circuits need to be frequently switched during interference injection, which not only increases the difficulty of operation, but also reduces 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 high-intensity electromagnetic interference environments. It is difficult to achieve real-time monitoring of the waveform, and signal acquisition is easily disturbed and distorted. This defect makes it impossible to accurately record the instantaneous changes of the injection signal, increases the test error, and affects the reliability of the 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 in different frequency bands. For scenarios where multi-band switching needs to be achieved in the same device, existing devices cannot flexibly adjust coupling and attenuation parameters, resulting in insufficient test response when the device faces interference environments of different frequency bands and intensities, limiting the comprehensiveness of anti-interference verification.

[0010] (6) Inadequate high-voltage and high-current protection design: In existing test systems, many injection devices do not take high-voltage design into consideration, which results in easy damage to the 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 the test. Summary of the invention

[0011] The purpose of the present invention is to provide a method and device for accurately injecting electromagnetic interference for loop-level immunity verification in order to solve the problems existing in the above-mentioned prior art.

[0012] The technical solution to achieve the purpose of the present invention is as follows: on the one hand, a precise electromagnetic interference injection device for loop-level immunity verification is provided, the device comprising 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 an electromagnetic interference signal and transmit it 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 loop of the device under test;

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

[0016] The device supports independent injection of multiple sensitive points, and injects interference signals at different sensitive points through a handheld injection probe to achieve anti-interference 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 single or a combination of multiple electromagnetic interference signal generators, supporting separate injection or superimposed injection of multiple electromagnetic interference signals.

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

[0020] Furthermore, n coupling network modules and a first switching unit are provided in the interference injection cavity, and different coupling network modules are switched to work by the first switching unit, that is, the gear position of the coupling network is adjusted to meet the transmission requirements of electromagnetic interference signals in different frequency bands;

[0021] The signal recovery cavity is provided with a plurality of attenuation network modules with different attenuation parameters and a second switching unit. The second switching unit is used to switch different attenuation network modules to work, that is, to adjust the gear position of the attenuation network module to achieve multi-level attenuation adjustment of the recovered electromagnetic interference signal, thereby ensuring stability during the signal recovery 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 baffle, and the vertical projections of the two PCBs on the shielding baffle 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, i.e., a sliding magnetically controlled switch, and a reed switch, and 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] Furthermore, the handheld injection probe is a pen-shaped structure, comprising a shell, wherein the shielding partition is arranged in the center of the shell along the axial direction thereof to divide the internal space of the shell into two parts, thereby forming the double-cavity structure;

[0025] The end surface of one end of the housing along the axial direction is divided into two mutually isolated areas, which communicate with the interference injection cavity and the signal recovery cavity respectively, and can contact with the sensitive points of the hardware loop at the same time, serving as the interference signal injection window of the interference injection cavity and the signal detection window of the signal recovery cavity respectively;

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

[0027] Furthermore, a clamping and fixing device is provided at the other end of the shell along the axial direction thereof, which is used to install the handheld injection probe on different platforms.

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

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

[0030] Outer shielding: The handheld injection probe is made of lightweight aluminum alloy;

[0031] The outer shield and the inner shield are filled with insulating silicone.

[0032] On the other hand, a method for accurate electromagnetic interference injection for loop-level immunity verification is provided, the method comprising:

[0033] Generate electromagnetic interference signals through conducted interference signal sources;

[0034] Inject electromagnetic interference signals into sensitive points of the internal circuit of the device under test through a handheld injection probe;

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

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

[0037] The electromagnetic interference signal waveform at the injection point is monitored in real time through the real-time monitoring module.

[0038] Compared with the prior art, the present invention has the following significant advantages:

[0039] (1) Accurate injection of interference signals at the loop level: The handheld injection probe of the present invention can accurately inject 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 anti-interference of electromagnetic sensitive points, thereby significantly improving the accuracy and effectiveness of the test and meeting the needs of refined testing.

[0040] (2) Flexible signal attenuation and coupling network switching: The probe integrates multiple sets of switchable attenuation networks and coupling networks. Operators can switch between different signal paths and attenuation multiples through simple magnetic switches or mechanical sliding switches to adapt to the requirements of multi-band and multi-intensity interference signals, significantly improving the flexibility and efficiency of operations 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 efficient real-time acquisition and transmission capabilities, and is connected to the oscilloscope located in the shielding box through a signal connector to achieve accurate monitoring of the interference signal waveform. This design ensures the synchronization of the injection and acquisition signals, provides distortion-free waveform display, makes the test data more complete and accurate, and effectively avoids the signal distortion problem in traditional testing.

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

[0043] (5) Adaptability to multiple stress environments: The present invention supports immunity testing under multiple stress environments. It can be placed in a high and low temperature test chamber to simulate the conditions of temperature stress and electromagnetic interference superposition, and conduct immunity verification that is closer to the actual working environment. Through comprehensive testing under multiple stress conditions, the system can comprehensively evaluate the immunity performance of the equipment and enhance the actual 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, which realizes a miniaturized design and facilitates flexible operation in complex hardware loops. The probe has a simple switching function and supports fast switching of different coupling networks and attenuation networks, ensuring fast response and efficient adaptation under different test conditions, thereby improving the applicability of the system in diversified tests.

[0045] (7) The present invention is compact and flexible in design and is suitable for the injection requirements of various electromagnetic interference signals. It is particularly suitable for anti-interference verification under multiple stress environments and has strong environmental adaptability and convenient operation.

[0046] The present invention is further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 Schematic diagram of an electromagnetic interference precision injection device for loop-level immunity verification in one embodiment.

[0048] Figure 2 FIG. 1 is a schematic diagram of the structure of a handheld injection probe in one embodiment, wherein Figure 2 (a) is a schematic diagram of the overall structure. Figure 2 (b) is a local schematic diagram of the interference injection cavity. Figure 2 (c) is a partial schematic diagram of the signal recovery cavity.

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

[0050] Figure 4 A top view of a handheld injection probe in one embodiment.

[0051] Figure 5 FIG. 1 is a schematic diagram of the internal circuit of a handheld injection probe in one embodiment.

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

[0053] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with 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 the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0055] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed 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 Figure 1 , provides an electromagnetic interference precision injection device for loop-level immunity verification, the device comprising 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 sensitive points of the hardware loop 4 of the device to be tested;

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

[0060] The device supports independent injection of multiple sensitive points, and injects interference signals at different sensitive points through a handheld injection probe 2 to achieve anti-interference verification at the loop level;

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

[0062] In order 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 where temperature stress and electromagnetic interference are superimposed, thereby realizing anti-interference testing under multi-stress environments and comprehensively evaluating the anti-interference performance of the equipment in complex environments. Figure 1 The multiple sensitive points shown in the figure indicate that the system is capable of accurately injecting interference and acquiring waveforms at key locations inside the loop, thereby improving the accuracy of the test and the validity of the data.

[0063] In the simulation test, the probe and the device under test can be placed together in a high and low temperature test chamber to perform temperature and electromagnetic interference superposition tests to enhance the reliability of the test results.

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

[0065] Here, the electromagnetic interference signal includes but is not limited to surge, electrical fast transient pulse group, damped oscillation wave signal and other signals or their combination to meet different types of electromagnetic interference test requirements.

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

[0067] Further, in one embodiment, in combination Figures 2 to 4 The handheld injection probe adopts a dual-cavity design, including an interference injection cavity and a signal recovery 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 sensitive points of the hardware loop 4; the signal recovery cavity is used to collect interference signals at sensitive points of the hardware loop 4 and transmit the collected signals to the real-time monitoring module 3.

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

[0069] Here, preferably, the shielding baffle is fixed in a middle position by a locking structure to provide two-way support.

[0070] Preferably, the signal transmission of the device of the present invention adopts a flexible coaxial cable, which is directly connected to the recovery loop to reduce signal loss and enhance pressure resistance, thereby ensuring signal integrity in a high-voltage environment.

[0071] Furthermore, in one of the embodiments, n coupling network modules and a first switching unit are provided in the interference injection cavity, and different coupling network modules are switched to work by the first switching unit, that is, the gear of the coupling network is adjusted to couple interference signals of different frequencies to the circuit to be tested, so as to meet the transmission requirements of electromagnetic interference signals in different frequency bands, and then adapt to the signal injection requirements of different intensities, thereby ensuring the flexibility of the test.

[0072] The signal recovery cavity is provided with a plurality of attenuation network modules with different attenuation parameters and a second switching unit. Different attenuation network modules are switched to work by the second switching unit, that is, the gear position of the attenuation network module is adjusted to achieve multi-stage attenuation adjustment of the recovered electromagnetic interference signal, thereby adjusting the strength of the recovered signal to ensure stability during the signal recovery process.

[0073] Preferably, in some embodiments, the coupling network module and the attenuation network module are connected to the flexible coaxial cable through a signal connector 11. Specifically: the coupling network module is connected to the 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 the real-time monitoring module 3 through a common signal connector and a second flexible coaxial cable 12. The flexible coaxial cable passes through the 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 traditional connection methods, this high-voltage signal connector can ensure stable signal transmission while reducing contact resistance and potential electromagnetic interference.

[0075] Here, it is further preferred that a high-voltage insulating protective 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 under high-voltage environment and ensure the stability of signal transmission and the safety of equipment.

[0076] It should be noted that the use of other connectors or high-voltage resistant designs to achieve the same function also falls within the scope of protection 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, respectively recorded as the first PCB 18 and the second PCB 16; the vertical projections of the two PCBs on the shielding partition do not overlap 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, and the flexible coaxial cable 5 is installed on the handheld injection probe 2 through the detachable buckle, and is connected to the grounding on the two PCBs through the through hole on the handheld injection probe 2. Here, the length of the flexible coaxial cable 5 is adjustable. The solution of this embodiment enables the device to be applicable to the grounding environment of any scenario.

[0080] Here, it is further preferred that the PCBs on both sides of the shielding partition are coated with aluminum foil, which further enhances the electromagnetic isolation effect between the two cavities and ensures that the signal is not disturbed during transmission.

[0081] Preferably, in some embodiments, Figure 5The coupling network module adopts but is not limited to an RC coupling network 17, which is composed of a plurality of coupling capacitors (C1, C2, C3...) and a series impedance resistor (R s1 , R s2 , R s3 ....)composition.

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

[0083] Here, it is further preferred that the coupling capacitor adopts a high-voltage ceramic capacitor that can withstand the impact of high-voltage interference signals to ensure stability under high-voltage environments; the series resistor adopts a high-precision high-voltage metal film resistor to ensure stable impedance matching, thereby ensuring the stability and anti-interference of signal transmission. It should be noted that if other components and materials with high-voltage resistance are used to achieve the same function, it also falls within the protection scope of the present invention.

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

[0085] Here, further preferably, the attenuation network module is provided with but 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 (R1-R3, R6) and inductors (L0, L1) of different resistance values.

[0086] Here, resistors of different resistance values ​​are used to adjust the attenuation ratio of the signal to meet the needs of signals of different strengths. The inductor and the attenuation resistor network work together to ensure impedance matching under high-frequency conditions, so that the signal remains stable during transmission.

[0087] Here, it is further preferred that the resistors in the attenuation network are high-voltage resistant metal oxide film resistors, which can operate stably under high-voltage signal conditions and avoid signal distortion, thereby ensuring the accuracy of signal acquisition.

[0088] Here, it is further preferred that the inductor material in the attenuation network is a ferrite material 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 recovered signal.

[0089] Here, it is further preferred to add a high-voltage resistant insulating coating around the key components and signal transmission paths of the attenuation network, and to provide a high-voltage resistant insulating sheath 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 adopts but is not limited to a combination of a magnetically controlled switch controlled by a sliding magnet, i.e., a sliding magnetically controlled switch 9 and a reed switch 21 , and the second switching unit adopts but is not limited to a mechanical sliding switch 8 .

[0091] Here, the sliding magnet controls the open and closed state of the reed switch, thereby switching between different coupling loops to meet different interference signal injection requirements. The gear position of the attenuation network is switched by a mechanized sliding switch, and then different attenuation paths are selected to meet the signal conditioning requirements under different test conditions.

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

[0093] Here, it is further preferred that the reed switch uses a high-pressure sealed reed switch, which can work safely in a high-voltage environment, and an insulating sleeve is added to 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 is a pen-shaped structure, including a shell, and the shielding partition is arranged in the center of the shell along its axial direction to divide the internal space of the shell into two parts, forming the dual-cavity structure.

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

[0096] Here, it is further preferred that the end face 7 of the shell at one end along its axial direction is divided into two isolated areas, which communicate with the interference injection cavity and the signal recovery cavity respectively, and can both contact with the sensitive points of the hardware loop 4, serving as the interference signal injection window of the interference injection cavity and the signal detection window of the signal recovery cavity respectively.

[0097] Here, further preferably, the interference signal injection window and the signal detection window are respectively connected to the PCB via spring pins 6. The spring pins 6 realize signal transmission between the interference signal injection window and the signal detection window and their corresponding PCBs, and are also used to realize the installation support function between components.

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

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

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

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

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

[0103] The outer shield and the inner shield are filled with insulating silicone.

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

[0105] The solution of this embodiment can work stably in an electromagnetic interference environment, ensuring that signal transmission is not interfered with by the outside world.

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

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

[0108] Generate electromagnetic interference signals through conducted interference signal sources;

[0109] Inject electromagnetic interference signals into sensitive points of the internal circuit of the device under test through a handheld injection probe;

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

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

[0112] The electromagnetic interference signal waveform at the injection point is monitored in real time through the real-time monitoring module.

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

[0114] The device and the equipment under test are placed in a high and low temperature test chamber to conduct multiple stress superposition tests to evaluate the anti-interference performance of the equipment in a complex environment.

[0115] If other injection probe configurations or test environments are used to achieve the same test function, it also falls within the protection scope of the present invention.

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

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

[0118] (2) Supporting comprehensive immunity testing in multiple 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) on the basis of electromagnetic interference testing. Combined with a high and low temperature test chamber, the device can test the immunity performance of the device in an environment with multiple stresses superimposed, enhancing the environmental simulation capability of the test, thereby more realistically reflecting the immunity performance of the device in the actual working environment.

[0119] (3) Improve the flexibility of probe design and ease of operation: The present invention uses a miniaturized design of a handheld test lead probe to enable operators to accurately locate and switch injection points in a compact and complex hardware loop. The probe has a fast switching function of multiple coupling networks and attenuation circuits, which not only facilitates flexible testing at different frequency bands and intensities, but also simplifies the operation process, improves test efficiency and flexibility, and adapts to a variety of test conditions.

[0120] (4) Enhanced real-time signal acquisition and monitoring capabilities: The present invention designs an oscilloscope placed in a shielded box with a real-time waveform monitoring function, which can accurately acquire and display signal waveforms in real time in a high-intensity electromagnetic interference environment, ensuring that the instantaneous changes of the injected signal are reflected without distortion. This real-time monitoring design improves the accuracy of test records and the reliability of results, ensuring that users can obtain high-quality immunity data.

[0121] (5) Modular design for multi-band coupling and multi-rate attenuation: The injection probe of the present invention is designed with a multi-band coupling network and a multi-rate adjustable attenuation module to meet the requirements of interference signals of different frequency bands and intensities. Through modular design, users can flexibly select and switch coupling and attenuation circuits according to test requirements, improve the device's adaptability 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-insulation materials and shielding structures inside the probe to ensure equipment safety and signal transmission stability under high-voltage environments. This protection design reduces operational risks and effectively reduces interference errors that may be caused 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 precision injection device and method for verifying loop-level immunity. The structure and working principle of the device are as follows: Figures 1 to 5 As shown in the figure, it mainly includes electromagnetic interference signal generator, handheld injection probe, oscilloscope placed in a shielding box, coaxial transmission line, coupling network and attenuation network. Specifically including:

[0125] (1) Structure of the precise electromagnetic interference fault 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 an interference signal of a specific frequency and intensity, which is transmitted to the handheld injection probe through a coaxial transmission line. The coupling network in the probe accurately injects the interference signal into a specific circuit inside the device. The signal is adjusted by the attenuation network and transmitted to the oscilloscope placed in the shielding box to ensure stable monitoring of the signal.

[0127] (2) Structure and function of 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 silicone is filled on both sides of the partition to ensure electrical insulation and independence of the cavity structure under high-voltage environments. The design of the probe enables it to accurately locate the injection point of the interference signal in a complex hardware loop, and to acquire the response of the interference signal in real time, supporting the needs of multi-point testing and acquisition.

[0129] (3) Hardware circuit structure

[0130] The hardware circuit of the device under test contains multiple functional modules and sensitive points, which can realize the anti-interference test from the overall to the chip pin level. The hardware circuit supports multi-point interference signal injection and global scanning. By performing precise interference injection and signal recovery at key sensitive points inside the device, the anti-interference ability of each module under different interference conditions is tested.

[0131] (4) Dual-cavity structure design and shell 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 silicone is filled around the partition to form an insulating structure that is resistant to high voltage and 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 metal braided layers to form a multi-layer shielding protection, providing high-strength electromagnetic isolation and impact protection.

[0133] (5) Coupling network design and component selection

[0134] The coupling network includes multiple coupling capacitors and resistors. The capacitors are high-voltage ceramic capacitors (C1, C2, C3) and the resistors are 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 achieves three-speed switching through a magnetically controlled switch and a reed switch to meet the transmission requirements of multi-band interference signals.

[0135] The specific components are as follows:

[0136] Coupling capacitors: 10pF, 20pF and 47pF high-voltage ceramic capacitors are used to meet the signal requirements of different frequency bands and ensure stability under high-voltage environments.

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

[0138] Switching different coupling paths is achieved through the combination of reed switches and magnetic switches. The three gears and switching switches built into the probe can flexibly adjust the signal path to meet the needs of multi-band signal injection. The reed switch components are selected to be high-voltage tolerant models to ensure the safety and reliability of high-voltage signals.

[0139] (6) Attenuation network (recovery loop) design and component selection

[0140] The attenuation network is used to adjust the strength of the recovery signal, and two attenuation ratios of 10 times and 100 times are designed. Key components include high-voltage metal oxide film resistors (to ensure signal stability under high-voltage conditions) and high-frequency ferrite inductors L0. The recovery circuit also adds high-voltage insulation coatings at key locations to ensure electrical insulation in high-voltage environments. The specific component selections are as follows:

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

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

[0143] Switching between different attenuation paths is achieved through a mechanical sliding switch. The built-in two-position switch can flexibly adjust the signal path to meet the injection requirements of signals of different strengths.

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

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

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

[0147] Application example: Equipment loop-level electromagnetic interference immunity test experimental process

[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 each device 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 real-time monitoring mode to observe the response of the interference signal.

[0150] (2) Set interference signal parameters

[0151] Select the interference signal type (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, you can choose a single interference signal output or multiple signal superposition mode to simulate the electromagnetic interference situation in the real working environment.

[0152] (3) Probe coupling network configuration

[0153] According to the requirements of the equipment test frequency band, the magnetic switch of the handheld injection probe switches different coupling capacitor values ​​(such as 10pF, 20pF, 47pF) to achieve accurate coupling of interference signals in different frequency bands. The combination of reed switch and magnetic switch realizes the switching of different coupling paths to ensure effective coupling of signals in different frequency bands.

[0154] (4) Set the signal attenuation ratio

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

[0156] (5) Connect and position the probe

[0157] Aim the pen tip of the handheld injection probe at 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 to accurately perform 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 pen tip probe touches the sensitive point of the device, the probe accurately injects the interference signal into the device circuit 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 an oscilloscope placed in a shielded box to monitor the waveform of the interference signal at the sensitive point in real time. The response of the device during the interference injection process, including the change and distortion of the signal waveform, is recorded for subsequent analysis.

[0162] (8) Multi-point interference injection

[0163] To fully evaluate the immunity of the device, point-by-point testing can be performed at different sensitive points in the hardware loop. Each time, an interference signal is injected and its response is monitored, and steps (3) to (7) are repeated to test the electromagnetic immunity of the device at different sensitive points.

[0164] (9) Multi-stress testing

[0165] The hardware loop and handheld injection probe are placed in a high and low temperature test chamber, and temperature stress is superimposed to simulate the working state of the equipment in an extreme environment. The superposition of temperature range (e.g. -40°C to 85°C) and electromagnetic interference signals simulates the equipment immunity in a real environment. Repeat interference injection and waveform monitoring to record the response of the equipment under complex stress conditions.

[0166] (10) Analysis and evaluation

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

[0168] The above shows and describes 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 the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An electromagnetic interference precision injection device for circuit-level immunity verification, characterized in that: The device comprises 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 an electromagnetic interference signal and transmit it to the handheld injection probe through a specific conduction path; The handheld injection probe is used to inject interference signals into sensitive points of the hardware loop of the device under test; The real-time monitoring module is connected to the handheld injection probe and is used to monitor the interference signal waveform at the interference signal injection point in real time; The device supports independent injection of multiple sensitive points, and injects interference signals at different sensitive points through a handheld injection probe to achieve anti-interference verification at the loop level; The real-time monitoring module supports multi-channel input to achieve synchronous monitoring of multiple sensitive points.

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

3. The electromagnetic interference precision injection device for loop-level immunity verification according to claim 1 is characterized in that: The handheld injection probe adopts a dual-cavity design, including an interference injection cavity and a signal recovery cavity, and the two cavities are isolated by a shielding partition to form an independent cavity structure; wherein the interference injection cavity is used to inject electromagnetic interference signals into sensitive points of the hardware loop; the signal recovery cavity is used to collect interference signals at sensitive points of the hardware loop and transmit the collected signals to the real-time monitoring module.

4. The electromagnetic interference precision injection device for loop-level immunity verification according to claim 3 is characterized in that: The interference injection cavity is provided with n coupling network modules and a first switching unit, and the first switching unit is used to switch different coupling network modules to work, that is, to adjust the gear of the coupling network to meet the transmission requirements of electromagnetic interference signals in different frequency bands; The signal recovery cavity is provided with a plurality of attenuation network modules with different attenuation parameters and a second switching unit. The second switching unit is used to switch different attenuation network modules to work, that is, to adjust the gear position of the attenuation network module to achieve multi-level attenuation adjustment of the recovered electromagnetic interference signal, thereby ensuring stability during the signal recovery process.

5. The electromagnetic interference precision injection device for loop-level immunity verification according to claim 4 is characterized in that: The coupling network module and the attenuation network module are respectively arranged on two PCBs installed on both sides of the shielding baffle, and the vertical projections of the two PCBs on the shielding baffle do not overlap and maintain a certain distance.

6. The electromagnetic interference precision injection device for loop-level immunity verification according to claim 4, 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, i.e., a sliding magnetically controlled switch, and a reed switch, and 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.

7. The electromagnetic interference precision injection device for loop-level immunity verification according to claim 3, characterized in that: The handheld injection probe is a pen-shaped structure, comprising a shell, wherein the shielding partition is arranged in the center of the shell along the axial direction thereof to divide the internal space of the shell into two parts, forming the double-cavity structure; The end surface of one end of the housing along the axial direction is divided into two mutually isolated areas, which communicate with the interference injection cavity and the signal recovery cavity respectively, and can contact with the sensitive points of the hardware loop at the same time, serving as the interference signal injection window of the interference injection cavity and the signal detection window of the signal recovery cavity respectively; The interference signal injection window and the signal detection window of the signal recovery cavity are respectively connected to the PCB through spring pins.

8. The electromagnetic interference precision injection device for loop-level immunity verification according to claim 7, characterized in that: The other end of the shell along the axial direction thereof is provided with a clamping and fixing device for mounting the handheld injection probe on different platforms.

9. The electromagnetic interference precision injection device for loop-level immunity verification according to claim 3, characterized in that: The handheld injection probe adopts internal and external multi-layer shielding, specifically: Inner shielding: Each cavity is filled with insulating silicone to wrap the circuit components to form an inner shielding layer, and the inner shielding layer is grounded to the shielding partition; Outer shielding: The handheld injection probe is made of lightweight aluminum alloy; The outer shield and the inner shield are filled with insulating silicone.

10. A precise electromagnetic interference injection method for loop-level immunity verification based on the device according to any one of claims 1 to 9, characterized in that: The method comprises: Generate electromagnetic interference signals through conducted interference signal sources; Inject electromagnetic interference signals into sensitive points of the internal circuit of the device under test through a handheld injection probe; Switch different coupling network modules to meet different test requirements; Switch different attenuation network modules to meet different test requirements; The electromagnetic interference signal waveform at the injection point is monitored in real time through the real-time monitoring module.

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