Diagnostic measurement system for electromagnetic compatibility experiment and matched rectification system

Abstract

The invention discloses a diagnosis and measurement system for an electromagnetic compatibility experiment and a matched rectification system. The diagnosis and measurement system comprises a broadband LISN, a difference and common mode interference separation module, a radiation emission interference positioning module, ultra-wideband current calipers, a system power supply line rectification assembly and a system internal interconnection cable rectification assembly. The system provides stable impedance through a broadband LISN, samples high-frequency and low-frequency interference signals by using a difference and common mode interference separation module and a current caliper, and separates a difference mode component from a common mode component. And the radiated emission interference positioning module detects equipment radiation leakage points and generates a shielding effectiveness report. The rectification assembly quickly solves the electromagnetic compatibility problem of the equipment, and ensures that the test standard is met. The system realizes efficient and accurate electromagnetic interference detection and rectification.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic compatibility, and in particular relates to a diagnostic measurement system and a matching rectification system for electromagnetic compatibility experiments. Background Art

[0002] With the rapid development of electronic technology, various electronic products and electrical equipment are increasing in number and their functions are becoming more and more complex, and their electromagnetic compatibility (EMC) issues are receiving more and more attention. In the existing technology:

[0003] In terms of electromagnetic compatibility diagnostic measurement. Traditional electromagnetic interference diagnostic tools often have single functions and can only detect electromagnetic signals within a limited frequency band. They cannot fully cover the wide frequency band that electronic products may involve in actual use scenarios, making it difficult to accurately capture and analyze some interference signals. For multi-source interference signals in complex electromagnetic environments, existing measurement equipment lacks effective signal separation and identification capabilities, making it difficult to accurately determine the specific location and generation mechanism of the interference source, resulting in a lack of accurate basis for subsequent rectification work.

[0004] In terms of electromagnetic compatibility rectification, the current rectification measures are usually trial adjustments based on experience. There is a lack of a systematic and targeted rectification plan generation mechanism. The rectification effect is difficult to guarantee and often requires repeated experiments, which increases R&D costs and time cycles. The current rectification implementation mainly relies on capacitors and inductors of various specifications and models. There is no standard rectification tool. During the rectification process, the required components are often missing, making it impossible to continue the rectification. This leads to low rectification efficiency, failure to adjust the rectification strategy in a timely manner, and failure to quickly make the product meet the requirements of electromagnetic compatibility standards. Summary of the invention

[0005] The present invention aims to solve the problems of incomplete diagnosis and measurement, inability to locate, lack of effective tools, low efficiency, and difficulty in ensuring consistency in existing electromagnetic compatibility tests. The purpose is to provide a diagnostic measurement system and a matching rectification system for electromagnetic compatibility experiments, which can comprehensively and accurately diagnose and measure electromagnetic interference, accurately find the problem points that need to be rectified according to the measurement results, and use a highly integrated rectification tool to implement the rectification system, so as to quickly make the product meet the requirements of electromagnetic compatibility standards. In the process of electromagnetic compatibility testing of electronic products, electrical equipment, etc., it is used to diagnose and measure electromagnetic interference problems and implement rectification.

[0006] In order to solve the technical problem, the technical solution of the present invention is:

[0007] A diagnostic measurement system and a matching rectification system for electromagnetic compatibility experiments, the system comprising: a wideband LISN, a differential common mode interference separation module, a radiation emission interference positioning module, an ultra-wideband current caliper, a system power supply line rectification component, and a system internal interconnection cable rectification component; the differential common mode interference separation module comprises a low-frequency current caliper;

[0008] The broadband LISN is powered by a power supply, the power supply port of the broadband LISN supplies power to the device under test, the ultra-wideband current caliper and the low-frequency current caliper are both clamped on the power supply line between the power supply port of the LISN and the device under test, the ultra-wideband current caliper, the differential common mode interference separation module and the radiation emission interference positioning module are all connected to a spectrum analyzer or an EMI receiver through a coaxial cable and then connected to a computer, the EMI detection port of the broadband LISN and the low-frequency current caliper both collect signals and input them into the differential common mode interference separation module; the radiation emission interference positioning module detects the device under test through a spectrum analyzer or an EMI receiver space;

[0009] The system power supply line rectification component is connected to the power supply line between the power supply port of the LISN and the device under test, and is used to rectify the system power supply line. The system internal interconnection cable rectification component is used to rectify the internal interconnection cables of the device under test.

[0010] Furthermore, when conducting an electromagnetic compatibility test, the wide-band LISN provides a stable impedance for the test, the high-frequency differential common-mode interference signal is sampled through the EMI detection port of the wide-band LISN, and the low-frequency differential common-mode interference signal is sampled by clamping the low-frequency current caliper on the power supply line, and then the differential common-mode interference separation module is used to separate the differential mode interference and common mode interference of the interference signal sampled on the power line of the device under test, and the separated signals are transmitted to the computer, and the specific separated differential mode component data and common mode component data are given through analysis and calculation by the test software.

[0011] Furthermore, the radiation leakage point of the device under test is tested and diagnosed and located through the radiation emission interference positioning module, and the test signal is transmitted to the computer. The test software automatically realizes the synchronous scanning control of the signal source and the spectrum analyzer according to the frequency domain shielding effectiveness test standard, automatically calculates the resonant frequency of the shielding body, automatically reads the test data, calculates the measured shielding effectiveness, and generates a frequency domain test report.

[0012] Furthermore, based on the separated differential mode component data and common mode component data and the measured shielding effectiveness, the electromagnetic compatibility problems of the equipment under test are quickly and reliably rectified through the system power supply line rectification components and the system internal interconnection cable rectification components until they meet the electromagnetic compatibility test standards.

[0013] Compared with the prior art, the advantages of the present invention are:

[0014] A diagnostic measurement system and a matching rectification system for electromagnetic compatibility experiments solve the problems of incomplete diagnostic measurement, inability to locate, lack of effective tools for rectification, low efficiency, and difficulty in ensuring consistency in existing electromagnetic compatibility tests. A system is provided that can comprehensively and accurately diagnose and measure electromagnetic interference, accurately find the problem points that need to be rectified based on the measurement results, and use highly integrated rectification tools to implement rectification, so as to quickly make the product meet the requirements of electromagnetic compatibility standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 , an overall system block diagram of a diagnostic measurement system and a matching rectification system for electromagnetic compatibility experiments of the present invention;

[0016] Figure 2 , a software framework diagram of a diagnostic measurement system and a matching rectification system for electromagnetic compatibility experiments of the present invention;

[0017] Figure 3 , the system power supply line test component is composed of the actual use wiring diagram;

[0018] Figure 4 , System power supply line test component diagram;

[0019] Figure 5 , filter circuit schematic;

[0020] Figure 6 , Schematic diagram of inductor box wiring (taking single-phase power supply as an example);

[0021] Figure 7 , Usage diagram (taking single-phase power supply as an example);

[0022] Figure 8 , the actual use of interconnection diagram;

[0023] Fig. 9 , filter module installation diagram. DETAILED DESCRIPTION

[0024] The specific implementation mode of the present invention is described below in conjunction with embodiments:

[0025] It should be noted that the structures, proportions, sizes, etc. shown in this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them, and are not used to limit the conditions under which the present invention can be implemented. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0026] At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0027] Embodiment 1:

[0028] like Figure 1 As described above, the overall system architecture: This system is mainly composed of a wideband LISN, a differential common mode interference separation module, a radiation emission interference positioning module, an ultra-wideband current caliper, a system power supply line rectification component, a system internal interconnection cable rectification component and supporting software. The modules are connected and data exchanged through coaxial cables, data cables, etc.

[0029] Detailed introduction of each module:

[0030] 1. Broadband LISN:

[0031] The ultra-wideband line impedance stabilization network provides stable impedance between the power supply and the reference ground of the device under test in the frequency range of 9kHz to 1GHz; at the same time, it isolates the power signal from the power grid from the measurement circuit to achieve the purpose of measuring the interference signal generated by the power supply of the device under test by the measurement receiver.

[0032] Further, the main functions:

[0033] Providing stable impedance:

[0034] The wideband LISN provides standardized impedance (usually 50Ω±10Ω) between the power supply line and the ground line of the equipment within the frequency range of 9kHz to 1GHz through the internal precisely designed network circuit, ensuring the consistency and standardization of the test environment.

[0035] Isolation power signal:

[0036] It isolates the power signal (low frequency) from the power grid from the measurement circuit through filtering and isolation networks to prevent power grid noise from interfering with the test results.

[0037] Collect interference signals:

[0038] LISN can accurately separate the high-frequency interference signal generated by the device under test on the power supply line, and output it to the spectrum analyzer or measurement receiver through the EMI detection port for spectrum analysis of the interference signal.

[0039] Technical features:

[0040] Ultra-wideband range:

[0041] Covering the frequency range from low frequency 9kHz to high frequency 1GHz, it meets the testing needs of modern complex electromagnetic interference environment.

[0042] Precise impedance matching:

[0043] Providing consistent impedance across the entire frequency range ensures repeatable test results and standards compliance.

[0044] High efficiency isolation capability:

[0045] Through effective filtering circuits, low-frequency power signals in the power grid are isolated to prevent external noise from affecting the measurement results.

[0046] Working principle:

[0047] Connection and power supply:

[0048] The grid power supply is connected to the device under test through the LISN, which provides a stable impedance and isolation network.

[0049] Signal separation:

[0050] The interference signal is transmitted to the LISN from the power supply line of the device under test, the low-frequency power signal is isolated, and the high-frequency interference signal is output through the dedicated EMI detection port.

[0051] Signal analysis:

[0052] The output interference signal is transmitted to a spectrum analyzer or measurement receiver for analysis of its amplitude and frequency distribution.

[0053] 2. Differential and common mode interference separation module:

[0054] The differential and common mode interference separation module can extract and separate the differential and common mode components in the power supply within the frequency range of 1kHz to 50MHz. It is mainly used for quantitative analysis of common mode interference and differential mode interference in conducted emission test interference signals. It provides data support for the rectification of conducted emission, especially the test of EMI filters.

[0055] Further, the main functions:

[0056] Extraction and separation of interference components: The differential and common mode interference separation module uses circuit design to accurately extract the interference signal in the power line and separate the differential mode component and common mode component.

[0057] Quantitative analysis: Provides support for the characteristic analysis of interference signals in conducted emission tests, and measures and calculates the frequency distribution and amplitude of differential mode interference and common mode interference respectively.

[0058] Provide test basis: The differential mode and common mode component data output by the module provide specific data support for the design and verification of electromagnetic interference (EMI) filters and the rectification of conducted emission problems.

[0059] Technical features:

[0060] Wide frequency range: Supports frequency range from 1kHz to 50MHz, covering the interference frequency band required for typical conducted emission tests.

[0061] High-precision separation: Through high-precision circuit design, the separation accuracy of differential mode and common mode signals is ensured to avoid signal aliasing or distortion.

[0062] Real-time output: Output separated differential and common mode interference signals, which is convenient for spectrum analyzers or other equipment to monitor and process the signals in real time.

[0063] Working principle:

[0064] Interference extraction: The power cord of the equipment under test (EUT) passes through the differential and common mode interference separation module, which receives and extracts the total interference signal in the cable.

[0065] Signal separation: Use circuit design to decompose the total interference signal into two parts.

[0066] Differential Mode Noise (DM): Interference signal flowing between two power lines (phase line and neutral line).

[0067] Common Mode Noise (CM): Interference signal that flows to the ground line at the same time.

[0068] Signal output: The separated differential mode signal and common mode signal are output separately and connected to a spectrum analyzer or data acquisition system for analysis and recording.

[0069] Application scenarios:

[0070] Conducted emission test: used to quantitatively analyze the differential mode and common mode interference components of the device under test, helping to evaluate the conducted interference characteristics of the device.

[0071] Design and verification of EMI filters: By analyzing the amplitude and frequency distribution of differential-mode and common-mode interference, the design of EMI filters is optimized to improve their ability to suppress target interference frequency bands.

[0072] Interference rectification support: Provides differential mode and common mode component data to provide a basis for targeted conducted interference rectification, ensuring that rectification measures are efficient and reliable.

[0073] Typical application process:

[0074] Equipment connection: Connect the differential and common mode interference separation module to the power line of the device under test and connect it to the test loop.

[0075] Signal acquisition and separation: The module extracts the total interference signal on the power supply line and separates it into differential mode and common mode.

[0076] Spectrum analysis: Analyze the output differential and common mode signals through a spectrum analyzer and record their amplitude and frequency distribution.

[0077] Optimize design: Based on the analysis results, optimize the EMI filter or adjust the circuit design to reduce interference.

[0078] Verify the rectification effect: Test the interference signal of the device under test again to ensure that it complies with the electromagnetic compatibility standards.

[0079] Summarize:

[0080] The differential and common mode interference separation module is an important tool in conducted emission testing. It helps to achieve quantitative analysis of interference sources by separating the differential and common mode interference components in the power line with high precision. Its output data provides a scientific basis for EMI filter design, diagnosis and rectification of equipment electromagnetic compatibility problems, and is an important technical means to improve the electromagnetic compatibility performance of equipment.

[0081] 3. Radiation emission interference positioning module:

[0082] The radiation emission interference positioning module is equipped with a near-field probe, a preamplifier, a portable screen effect test antenna, and a signal source. The hole leakage parts of the tested equipment such as shelters and cabinets are usually located at the edges and corners of the shielding body, which is very hidden. When the shielding effectiveness of a certain test frequency point does not meet the requirements, the standard antenna used to test a large local area cannot accurately locate the leakage part (it cannot reach the leakage part, the size is large and the detection accuracy is poor), which will lead to blind rectification in the later stage and half the result with twice the effort. The use of near-field probes with different positioning accuracy can accurately locate the radiation leakage position. Combined with portable screen effect test antennas and signal sources, the shielding effectiveness of various shielding bodies can be tested and problems can be rectified.

[0083] 4.Ultra-wideband current caliper:

[0084] Ultra-wideband current calipers are the most effective and repeatable test probes for electromagnetic coupling tests on power cables (10kHz to 200MHz) of various devices in the system. By placing the interconnecting cables in the calipers and placing them in differential and common modes, it is possible to distinguish between differential mode (electromagnetic coupling transmitted through ground wires or power wires) and common mode (electromagnetic coupling transmitted through line-to-line coupling or field-to-line) conducted electromagnetic interference on the interconnecting lines. Since the current calipers are clamped on the tested cables for non-contact measurement, the calipers are the simplest and most reliable test method for coupling tests or interference source location tests on cables in field environments.

[0085] 5. System power supply line rectification components:

[0086] For the electromagnetic compatibility rectification of the system power supply interface, different types of inductor / capacitor combination toolboxes (compatible with transient suppression) are needed to suppress interference from 25Hz to 50MHz. This component solves the complexity of temporarily building a filter circuit in actual rectification and provides a variety of filter circuit combinations, which is convenient and fast, and safety and reliability are guaranteed.

[0087] In order to solve the problems of conducted emission, radiated emission and electromagnetic pulse protection of the system, a rectification component with adjustable parameters is designed, which is suitable for testing and rectification during the electromagnetic compatibility test. Since EMI filters, that is, components integrating inductors and capacitors, are mainly used to solve conducted emission and radiated emission, the inductor / capacitor combination design is carried out according to this requirement. At the same time, in order to solve the problem of transient protection, transient protection devices are added on the basis of the original circuit. Finally, the inductor / capacitor / transient protection combination rectification component is designed to solve the rectification of transient protection, conducted emission and radiated emission projects, as well as the rectification of conducted and radiated sensitivity projects.

[0088] The system power supply line test components include two types of two-wire components and four-wire components. Among them, the two-wire component includes one single-phase common differential mode combined inductor tool box, four single-phase capacitor / transient protection combination tool boxes of three voltages each, which are used to insert the reserved capacitors in the inductor tool box; the four-wire component includes one three-phase four-wire common differential mode combined inductor tool box, and four three-phase four-wire capacitor / transient protection combination tool boxes, as shown in Table 1 below.

[0089] Table 1 - System power line test component composition and specific quantity

[0090]

[0091]

[0092] The single-phase common-differential mode combined inductor toolbox is an EMI choke component with selectable current and inductance. This toolbox is combined with the single-phase capacitor / transient protection combined toolbox for low-pass filtering to achieve broadband EMI filtering and electromagnetic pulse interference protection for power lines. It is suitable for CE and RE rectification of 10kHz to 50MHz frequency bands of equipment powered by 28VDC, 270VDC, and single-phase 115V / 400Hz, as well as rectification of conducted and radiated sensitivity items. In particular, the flexible combination of current and inductance enables rapid implementation of rectification measures and rapid optimization of component parameters. It greatly shortens the fault diagnosis cycle, thereby improving the efficiency of fault diagnosis and resolution of electronic systems.

[0093] The single-phase capacitor / transient protection combination toolbox is an EMI high-frequency bypass component that can preset the capacitance, and at the same time, it is a low-frequency transient bypass component that can preset the large energy protection voltage. The low-pass filter combination of this toolbox and the single-phase common differential mode inductor box can realize broadband EMI filtering and electromagnetic pulse interference protection of the power line. It is suitable for CE and RE rectification of the 10KHz~50MHz frequency band of equipment powered by two polarities, as well as rectification of conducted and radiated sensitivity items. In particular, the switch selection method for selecting capacitance and transient protection voltage realizes the rapid implementation of rectification measures and the rapid optimization of component parameters. It greatly shortens the fault diagnosis cycle, thereby improving the efficiency of fault diagnosis and resolution of electronic systems.

[0094] The three-phase four-wire system is the same as the above single-phase system.

[0095] How to use the system power line rectification component (using single-phase as an example):

[0096] Taking single-phase power supply as an example, the system power supply line test assembly is connected to the equipment during the test as shown in the figure Figure 3 and Figure 4 As shown, the input end is connected to the LISN and the output end is connected to the device under test.

[0097] Taking single-phase power supply as an example, Figure 5 The filter circuit shown is connected to the device under test;

[0098] The inductors are L-1, L-3 and L-5, such as Figure 6 Connect the wires as shown, and put a shielding braid on the cable at the output end of the system power supply line test component and ensure that the shielding braid is well grounded;

[0099] Insert the capacitor box in sequence Figure 6 In the socket in the red circle, the required capacitance value is controlled by the switch;

[0100] After connecting Figure 7 As shown, put the cover of the inductor box on and then conduct the test.

[0101] 6. System internal interconnection cable rectification components:

[0102] This component is different from the above-mentioned system power line rectification component in that it has the ability to make rapid rectifications. This tool is a set of quick-plug shielding and filtering integrated components specially designed by Kairong Company based on its understanding of the mechanisms, frequency bands and magnitudes of interference generated by various power supplies and signals, as well as years of rectification experience. Through specific tooling, it can be quickly plugged in and out to improve rectification efficiency. It solves the prominent problem that filtering and shielding between interconnected cables of equipment cannot be met at the same time during temporary rectification. It has the characteristics of fast operation, easy replacement and a full range of types.

[0103] The system internal interconnection cable test assembly consists of three parts: quick plug-in fault diagnosis tooling, serialized filter module plug-in toolbox, and direct module plug-in toolbox. As shown in Table 3-4, the configuration of a set of system internal interconnection cable test assembly is shown in Table 2:

[0104] Table 2 - Configuration of the system internal interconnection cable test assembly

[0105]

[0106] Table 3 - Configuration list of the serialized filter module plug-in toolbox

[0107]

[0108] Table 4 - Configuration checklist for the pass-through module plug-in toolbox

[0109] Serial number Part Name Specification quantity Remark 1 Mixed Signal Interface Channel Pass-Through Module 5A / line×9 lines 9 — 2 Video signal dedicated interface channel pass-through module 3A / line×30 lines 1 —

[0110] How to use: Install the quick-plug fault diagnosis tool according to Figure 8 In the interconnection lines of the serially connected devices, according to the analysis, the lines with large interference are connected to the filter module, and the other lines are connected to the pass-through module to test the interference suppression effect of conducted emission and radiated emission; then the pass-through module is gradually replaced with the filter module until the system interference disappears;

[0111] The through module or filter module is reliably interconnected with the quick-plug fault diagnosis tooling through the DB9 connector, such as Fig. 9 ;

[0112] The shield tail of the equipment lead wire and the input and output connector of the plug-in fault diagnosis tooling are overlapped 360° to ensure the shielding integrity of the cable; the filtering or pass-through module and the plug-in fault diagnosis tooling are screwed to achieve line conductivity and shielding integrity.

[0113] 7. Supporting software:

[0114] The supporting test software integrates the power supply line low-frequency current caliper EMI sampling current loss coefficient module and the line impedance stabilization network EMI detection port voltage loss coefficient module. In the test interface, the power supply line low-frequency current caliper EMI sampling current loss coefficient module is called to achieve differential common mode isolation and signal extraction in the 1KHz≤f<10KHz frequency band; the line impedance stabilization network EMI detection port voltage loss coefficient module is called to achieve differential common mode isolation and signal extraction in the 10KHz≤f≤50MHz frequency band; it supports the test and fault diagnosis of the electric field radiation emission characteristics of the chassis cabinet or product; it has a rich electromagnetic compatibility standard database and a large number of typical electromagnetic interference case knowledge bases. By comparing the analyzed signal characteristics with the standards and cases in the database, it can quickly and accurately determine the type of electromagnetic interference, the cause of the occurrence, and the specific location of the related interference source.

[0115] Further, the core functional modules:

[0116] Power supply line low frequency current caliper EMI sampling current loss coefficient module

[0117] Function description: used to compensate for the loss coefficient of differential mode and common mode interference current signals in the power supply line within the frequency band of 1kHz≤f<10kHz. Main features: After calling this module, the interference characteristics in the power supply line are extracted by sampling the current signal and combining the loss coefficient compensation. It realizes high-precision extraction of differential mode and common mode interference, which is suitable for low-frequency interference characteristic analysis.

[0118] Application scenarios: Analyze the interference source of low-frequency power supply lines, which is often used to diagnose interference problems in high-current equipment or industrial power supply lines.

[0119] Line Impedance Stabilization Network (LISN) EMI detection port voltage loss coefficient module

[0120] Functional description: Used to analyze the power line voltage signal extracted by LISN in the frequency band of 10kHz≤f≤50MHz, and separate differential mode and common mode interference. Main features: Based on voltage signal sampling, compensation calculation is performed in combination with circuit loss characteristics (voltage loss coefficient). In the medium and high frequency bands (10kHz~50MHz), high-precision differential and common mode interference extraction and separation is achieved.

[0121] Application scenarios: Mainly used for analysis of conducted interference characteristics of equipment power supply lines, including high-frequency interference location and filter optimization design.

[0122] Other key features

[0123] Equipment electric field radiation emission characteristics test:

[0124] Functional description: Test the electric field radiation characteristics of the device housing, chassis cabinet or product. Main features: Support the measurement of the internal and external electromagnetic field emission intensity and distribution characteristics of the device. The test software can collect and visualize radiation intensity data in real time. Application scenarios: Radiation emission testing and rectification, such as optimizing the device shielding design or reducing the radiation leakage of the chassis cabinet.

[0125] Fault diagnosis function:

[0126] Functional description: Locate the interference source and fault point of the equipment based on the characteristics of the sampled signal. Main features: Analyze the extracted differential mode and common mode interference signals, as well as the electric field radiation characteristic data. Quickly determine the interference type, possible cause and location of the interference source based on the frequency distribution and amplitude characteristics of the signal. Application scenarios: Diagnosis of radiation interference leakage points. Accurately locate the conduction and radiation interference problems of the equipment.

[0127] Database and knowledge base functions

[0128] Electromagnetic compatibility standards database:

[0129] Function description: Built-in rich international and industry electromagnetic compatibility standards (such as CISPR, IEC, GJB standards, etc.). Features: Supports automatic comparison and analysis of test signals and standard limits to determine whether the equipment meets the standards. Covers multiple test standards such as conducted emission and radiated emission to ensure clear rectification direction.

[0130] Electromagnetic Interference Case Knowledge Base: Functional Description: A large number of typical electromagnetic interference cases are collected, including interference types, causes and solutions. Features: Based on the standard test software and the test signal curves that have been obtained, the software can further identify the emission characteristics of the test data, analyze the data exceeding the standard, and compare multiple test curves under the same project. It has a fault diagnosis test function suitable for typical test products, supports the test and fault diagnosis of electromagnetic radiation emission characteristics of chassis cabinets or products, and realizes the location of typical interference sources. Application scenario: Helps to quickly determine the type and cause of interference, and provides a basis for product design and rectification.

[0131] Comprehensive analysis and comparison functions:

[0132] Signal feature analysis: The software combines the spectrum, amplitude and other features of the sampled signal and compares them with the standard database limits and case library. Accurately identify interference types, such as differential mode, common mode or electric field radiation interference.

[0133] Interference source location: By comparing signal features with typical features in the case library, the software can efficiently determine the location of the interference source, such as the power supply interface, power cable, or internal circuit of the device.

[0134] Quickly output results: Generate detailed test reports, including the spectrum distribution of interference signals, interference types, causes and possible interference source locations.

[0135] Comprehensive process of testing and rectification

[0136] S1: Test preparation:

[0137] By calling the power line EMI sampling current loss coefficient module and the LISN voltage loss coefficient module, interference signals are extracted and separated for the low frequency band (1kHz~10kHz) and the medium and high frequency band (10kHz~50MHz) respectively.

[0138] S2: Data Analysis:

[0139] The extracted signal features are compared with the standard limits and case knowledge base in the database to determine the type and cause of interference.

[0140] S3: Diagnosis and Correction:

[0141] Locate the interference source, combine the solutions recommended by the case knowledge base, and select appropriate filters or shielding measures for rectification.

[0142] S4: Verification and reporting:

[0143] Verify the rectification effect through testing, ensure that the interference problem is eliminated, and generate a test and rectification report.

[0144] Summarize:

[0145] The supporting test software integrates multiple functional modules and a rich database to accurately extract power line interference signals, analyze electric field radiation emission characteristics, quickly locate interference sources, and provide scientific rectification suggestions. Its high efficiency, accuracy and convenience provide strong technical support for electromagnetic compatibility testing and rectification.

[0146] Embodiment 2:

[0147] When conducting electromagnetic compatibility tests, a wideband LISN is used to provide a stable impedance for the test to ensure the accuracy of the test; the differential and common mode interference separation module is used to separate and extract the interference on the power line of the device under test, and then the separated and extracted signals are transmitted to the computer, and the specific separated differential mode component data and common mode component data are given through software analysis and calculation; the radiation emission interference positioning module is used to test and diagnose the radiation leakage point of the device under test, and the test signal is transmitted to the computer. The software automatically realizes the synchronous scanning control of the signal source and the spectrum analyzer according to the frequency domain shielding effectiveness test standard; automatically calculates the resonant frequency of the shielding body; automatically reads the test data, calculates the measured shielding effectiveness, and generates a frequency domain test report; combined with the results of the diagnostic test, the system power line rectification component and the system internal interconnection cable rectification component are used to quickly and reliably rectify the electromagnetic compatibility problems of the device under test until it meets the electromagnetic compatibility test standard. Specifically including:

[0148] 1. Provide stable impedance through wide-band LISN to ensure test accuracy

[0149] Wideband LISN (Line Impedance Stabilization Network) is one of the core components of the test. Stable impedance: Wideband LISN provides a stable standard impedance (usually 50Ω) for the power line of the equipment under test (EUT), covering a wide bandwidth range from 9kHz to 1GHz. Signal acquisition: LISN separates the conducted interference signal from the power line of the equipment under test, and isolates the noise interference in the external power supply to avoid affecting the test results. Signal output: The separated interference signal is output from the EMI detection port of the LISN to a spectrum analyzer or other test equipment for further analysis. Function: Ensure stable power supply conditions and eliminate the impact of power supply impedance fluctuations on interference signal measurement, thereby improving the accuracy and repeatability of test results.

[0150] 2. Differential and common mode interference separation and extraction

[0151] Use the differential and common mode interference separation module to perform differential and common mode separation and extraction of interference signals on the power supply line. Signal separation and extraction: Differential mode interference (DM): Interference signals existing between the phase line and the neutral line of the power supply line. Common mode interference (CM): Interference signals existing on both the phase line and the neutral line, usually flowing to the ground line. The differential and common mode interference separation module combines low-frequency current calipers and ultra-wideband current calipers to extract interference signals in the frequency band of 1kHz to 50MHz. Signal transmission: The separated differential mode signal and common mode signal are transmitted to the spectrum analyzer via a coaxial cable, and then transferred to a computer for further analysis. Data processing: The extracted interference signal is subjected to spectrum analysis through the supporting software to identify its frequency distribution and amplitude characteristics. The software automatically calculates and generates the separated differential mode interference component data and common mode interference component data, and provides a visual report.

[0152] 3. Testing and diagnosis of radiated emission interference

[0153] Use the radiation emission interference positioning module to detect the radiation emission characteristics and leakage points of the device under test. Radiation signal detection: Use a spectrum analyzer and a radiation positioning antenna to test the radiation signals of the housing, chassis cabinet, and internal cables of electronic products or electrical equipment. Leakage point positioning: The module determines the specific location of the radiation leakage by accurately measuring the strength of the electromagnetic field in space. Combined with high-sensitivity detection equipment, it captures the intensity changes of the radiation signal and identifies the weak points of the equipment shielding. Automated testing and analysis: The software automatically and synchronously controls the signal source and the spectrum analyzer according to the frequency domain shielding effectiveness test standard to achieve spectrum scanning. Automatically calculate the resonant frequency of the shielding body (the resonance point of the equipment housing) and the main frequency band of the radiation interference. Automatically read and store test data, analyze the shielding effectiveness and generate a frequency domain test report, providing detailed shielding body performance parameters.

[0154] 4. Analysis and diagnosis of test results

[0155] Comprehensive data analysis: Correlate the data of conducted interference and radiated interference to confirm the main source of interference. Compare signal characteristics with the built-in electromagnetic compatibility standard database (such as CISPR, IEC, GJB standards) and electromagnetic interference case knowledge base: determine whether the interference exceeds the standard. Analyze the type of interference (differential mode, common mode or radiated interference). Infer the possible cause of the interference and its related sources (such as power interface, internal cable or casing leakage, etc.). Fault location: Combine differential mode / common mode data and radiation signal test results to accurately locate the specific location of the interference source, such as power supply lines, internal interconnect cables, shielding bodies or equipment casings.

[0156] 5. Rectification of electromagnetic compatibility issues

[0157] Through the system power supply line rectification components and the system internal interconnection cable rectification components, the electromagnetic compatibility problems of electronic products or electrical equipment can be rectified quickly and reliably.

[0158] (1) System power line rectification components: Scope of application: Solve the problems of conducted emission, radiated emission and transient interference of power lines. Rectification method: Use the inductor / capacitor combination toolbox to build a suitable filter circuit according to the interference frequency band (25Hz~50MHz). Add transient protection devices (such as transient suppression diodes, varistors) to suppress electromagnetic pulses or power spike interference. Adjust the filtering parameters, optimize the performance of the EMI filter, and reduce the conducted emission interference. Use shielding measures to reduce the radiation of the power line to the outside world. Result verification: Tests confirm that the power line interference has been reduced to meet the standard requirements.

[0159] (2) System internal interconnect cable rectification components: Application scope: Solve the filtering and shielding problems of signal lines inside the equipment. Rectification method: Use quick-plug shielded filter integrated components to achieve differential and common mode interference suppression of signal lines. Combine the filter and shielding layer design to optimize the electromagnetic compatibility performance of the signal line and solve the radiation leakage problem. Adjust the cable layout to reduce cross interference between cables and avoid the formation of antenna effect. Result verification: Retest the signal line after rectification to ensure that both radiation and conducted interference meet the standards.

[0160] 6. Generate a complete test and rectification report

[0161] Report content: Conducted interference test data: differential mode, common mode component spectrum distribution and amplitude. Radiated emission test data: equipment shielding effectiveness, radiation intensity distribution, resonant frequency. Fault diagnosis results: interference type, cause and source location. Corrective measures: specific correction methods and implementation details. Verification results: whether the corrected equipment meets the electromagnetic compatibility standards. Automated output: The software automatically generates standardized test and correction reports, providing visual charts and suggestions.

[0162] Embodiment 3:

[0163] 1. System power line rectification components:

[0164] Function and goal: The system power line rectification component is designed for electromagnetic compatibility (EMC) testing and rectification, and provides an integrated filtering and protection solution for the conducted emission, radiated emission and transient protection of the power supply interface. By suppressing interference from 25Hz to 50MHz, it ensures that the equipment under test meets the EMC standard.

[0165] Working principle: Inductor / capacitor combination filtering: Through the integrated inductor and capacitor combination design, the interference signals in the low frequency to medium and high frequency range on the power line are filtered out. The inductor suppresses differential mode interference, and the capacitor suppresses common mode interference. The combination of the two can achieve full-band suppression of conducted interference. A variety of filter circuit combinations are provided (such as π-type filters, T-type filters, etc.), and users can choose the appropriate filter configuration according to different interference frequency characteristics.

[0166] Transient suppression function: Add transient protection devices (such as transient suppression diodes, varistors, etc.) to quickly suppress transient spike interference introduced in the power line due to electromagnetic pulses (EMP) or power fluctuations, thereby protecting the safety of the equipment circuit.

[0167] Parameter adjustability: The component design supports parameter adjustment of inductors and capacitors. Users can adjust the cutoff frequency and suppression capability of the filter according to test data to meet different test requirements.

[0168] Features and advantages: Modular design: Pre-designed multiple filter combinations eliminate the need for complex temporary circuit construction during the test process, greatly simplifying the rectification work. Fast and efficient: Plug-and-play components support fast switching of different filter configurations, greatly improving the efficiency of testing and rectification. High safety and reliability: Integrated high-quality filter components and transient protection components ensure the long-term stability of the rectification circuit and equipment safety. Versatility: Suitable for solving the conducted emission problems (differential mode and common mode interference) of the power supply line, the radiated emission problems, and the transient electromagnetic pulse protection needs of the equipment.

[0169] Application scenarios: Conducted emission test rectification: Suppress differential and common mode interference in the power supply interface to improve the conduction compatibility of the equipment. Radiated emission rectification: Reduce the impact of the power supply line on the radiation of the equipment by improving the radiation resistance of the power supply line. Transient protection: Protect the equipment from power spike interference, electromagnetic pulse (EMP) and lightning surge.

[0170] 2. System internal interconnection cable rectification components:

[0171] Function and goal: The system internal interconnect cable rectification component focuses on solving the electromagnetic compatibility problems in the signal interconnection cables inside the equipment, especially the filtering and shielding problems of the internal cables. The component improves the rectification efficiency through the integrated design of shielding and filtering with quick plug-in, ensuring that both conducted and radiated interference meet the EMC standards.

[0172] Working principle: Shielding and filtering integration: Adopting optimal circuit design, shielding and filtering functions are integrated into one component, the shielding layer isolates external interference, and the filter suppresses the conducted interference in the signal line. The internal filter can be a low-pass filter, a band-pass filter or a band-stop filter, and the appropriate filtering method is selected for different interference frequency bands.

[0173] Quick plug-in design: The components are designed with specific tooling to achieve quick plug-in and pull-out, making it easy to quickly replace different types of shielding filters during testing and rectification to meet temporary testing needs.

[0174] Interference characteristic optimization: According to the interference characteristics of signal lines of different devices (such as frequency band and interference intensity), the shielding materials and filter parameters in the components can be flexibly matched to achieve more efficient interference suppression effect.

[0175] Features and advantages: Rapid rectification capability: Modular design and quick plug-in tooling enable convenient rectification operations, greatly shortening testing and rectification time. Complete range: Covers a variety of filters and shielding structures to meet the needs of different equipment cables and interference characteristics. High adaptability: Suitable for various types of power cables, data cables and signal cables, especially complex cable layouts inside equipment. High reliability: The components are optimized to maintain stable performance after multiple plug-in operations and provide long-term electromagnetic compatibility guarantees.

[0176] Application scenarios: Equipment signal line interference rectification: used to solve the simultaneous shielding problem of conducted interference and radiated interference in interconnected cables. Sensitivity rectification: improve the cable's ability to resist electromagnetic interference and reduce the impact of external interference on the normal operation of the equipment. Equipment rectification verification: during the EMC test process, quickly switch different shielding and filtering components to verify the effectiveness of rectification measures.

[0177] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

[0178] Many other changes and modifications may be made without departing from the concept and scope of the present invention.It should be understood that the present invention is not limited to the specific embodiments, and the scope of the present invention is defined by the appended claims.

Claims

1. A diagnostic measurement system and a matching rectification system for electromagnetic compatibility experiments, characterized in that: The system includes: a broadband LISN, a differential and common mode interference separation module, a radiation emission interference positioning module, an ultra-wideband current clamp, a system power supply line rectification component, and a system internal interconnection cable rectification component; the differential and common mode interference separation module includes a low-frequency current clamp; The broadband LISN is powered by a power supply, the power supply port of the broadband LISN supplies power to the device under test, the ultra-wideband current caliper and the low-frequency current caliper are both clamped on the power supply line between the power supply port of the LISN and the device under test, the ultra-wideband current caliper, the differential common mode interference separation module and the radiation emission interference positioning module are all connected to a spectrum analyzer or an EMI receiver through a coaxial cable and then connected to a computer, the EMI detection port of the broadband LISN and the low-frequency current caliper both collect signals and input them into the differential common mode interference separation module; the radiation emission interference positioning module detects the device under test through a spectrum analyzer or an EMI receiver space; The system power supply line rectification component is connected to the power supply line between the power supply port of the LISN and the device under test, and is used to rectify the system power supply line. The system internal interconnection cable rectification component is used to rectify the internal interconnection cables of the device under test.

2. A diagnostic measurement system and a matching rectification system for electromagnetic compatibility experiments according to claim 1, characterized in that: When conducting an electromagnetic compatibility test, the wide-band LISN provides a stable impedance for the test, the high-frequency differential common-mode interference signal is sampled through the EMI detection port of the wide-band LISN, and the low-frequency differential common-mode interference signal is sampled by clamping the low-frequency current caliper on the power supply line, and then the differential common-mode interference separation module is used to separate the differential mode interference and common mode interference of the interference signal sampled on the power line of the device under test, and the separated signals are transmitted to the computer, and the specific separated differential mode component data and common mode component data are given through analysis and calculation by the test software.

3. A diagnostic measurement system and a matching rectification system for electromagnetic compatibility experiments according to claim 2, characterized in that: The radiation leakage point of the device under test is tested and diagnosed and located through the radiation emission interference positioning module, and the test signal is transmitted to the computer. The test software automatically realizes the synchronous scanning control of the signal source and the spectrum analyzer according to the frequency domain shielding effectiveness test standard, automatically calculates the resonant frequency of the shielding body, automatically reads the test data, calculates the measured shielding effectiveness, and generates a frequency domain test report.

4. A diagnostic measurement system and a matching rectification system for electromagnetic compatibility experiments according to claim 3, characterized in that: Based on the separated differential mode component data and common mode component data and the measured shielding effectiveness, the electromagnetic compatibility problems of the equipment under test are quickly and reliably rectified through the system power supply line rectification components and the system internal interconnection cable rectification components until they meet the electromagnetic compatibility test standards.

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