Electromagnetic compatibility test method and test system for industrial control power supply

Abstract

The invention discloses an electromagnetic compatibility testing method and an electromagnetic compatibility testing system for an industrial control power supply, which are used for evaluating conducted interference, radiated interference and immunity performance. The system comprises a load module, a signal connection module, an electromagnetic interference measurement module, an immunity test module, a data processing module and a hardware acceleration module. The load module simulates the actual working state of the industrial control power supply through resistive, inductive, capacitive and dynamic loads; the signal connection module adopts high-frequency shielding and grounding optimization design, so that external interference is reduced; the electromagnetic interference measurement module is combined with the frequency domain analysis and time domain response module to capture interference signal characteristics and power supply dynamic output; the data processing module generates an electromagnetic compatibility report through a comprehensive evaluation algorithm; and the hardware acceleration module realizes real-time processing of high-frequency sampling data by utilizing the FPGA. The method is suitable for the electromagnetic compatibility test of the industrial control power supply in the fields of industrial automation, communication equipment and power electronics, and has wide engineering application value.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial control equipment, in particular to an electromagnetic compatibility testing method and a testing system for an industrial control power supply. Background Art

[0002] Industrial control power supplies are key components in the fields of industrial automation, communication equipment, and power electronics, and their performance directly affects the stability and reliability of the system. In complex industrial environments, industrial control power supplies must not only provide continuous and stable energy supply for equipment, but also need to deal with various potential electromagnetic interference (EMI), including but not limited to conducted interference, radiated interference, and transient interference signals. These electromagnetic interferences can cause equipment to operate abnormally, performance degradation, and even cause system failures, posing a major threat to the overall reliability of the system. Therefore, the electromagnetic compatibility performance of industrial control power supplies has become one of the focuses of attention in the industrial field.

[0003] At present, electromagnetic compatibility testing of industrial power supplies usually involves the following three key dimensions: conducted interference testing, radiated interference testing, and immunity testing. Conducted interference testing focuses on high-frequency noise signals conducted by industrial power supplies on the grid or load side, and the test range is usually 150 kHz to 30 MHz; radiated interference testing is used to evaluate the electromagnetic field radiation intensity of industrial power supplies in the frequency range of 30 MHz to 1GHz; and immunity testing simulates the working performance of industrial power supplies under interference signals such as electrical fast transient pulse groups (EFT), surges, and radio frequency electromagnetic fields. However, existing testing methods and equipment have many deficiencies in terms of efficiency, applicability, and accuracy.

[0004] First, the testing capabilities of existing equipment are limited and the testing process is complicated. Traditional electromagnetic compatibility test equipment is mostly targeted at a single interference type, and usually requires the use of conducted interference measurement equipment, radiated interference measurement equipment, and immunity test equipment, and these devices lack linkage. In the actual testing process, operators need to frequently replace equipment and test tools, resulting in a lengthy and complicated testing process, which not only increases the workload, but may also cause signal loss or data inconsistency due to equipment switching. In addition, the decentralized testing process cannot fully evaluate the electromagnetic compatibility performance of industrial control power supplies in complex environments, limiting the test efficiency and application value.

[0005] Second, the existing technology cannot truly simulate the dynamic working state of industrial control power supplies. In actual operation, the load characteristics of industrial control power supplies usually change dynamically with the working state. For example, scenarios such as industrial equipment startup, load switching, and frequency adjustment will cause frequent changes in the resistance, inductance, and capacitance characteristics of the load. However, most existing electromagnetic compatibility test equipment uses fixed or static load simulation technology, which cannot effectively simulate the dynamic working conditions of industrial control power supplies. Such static test conditions easily lead to deviations between the test results and the actual application conditions, reducing the credibility of the test results.

[0006] Third, the real-time processing capability of high-frequency interference signals is insufficient, which affects the test accuracy. In electromagnetic compatibility tests, especially immunity tests and high-frequency interference tests, the dynamic response of industrial control power supplies under the action of interference signals usually changes on a microsecond time scale. If the real-time processing capability of the test equipment is insufficient and the time correlation between the interference signal and the output signal of the industrial control power supply cannot be captured, important transient change information may be missed, affecting the accuracy of the test results. In addition, the existing equipment is weak in data processing capabilities, and the analysis and presentation of test results mostly rely on manual processing, which is inefficient and error-prone.

[0007] Fourth, the test data is not standardized and comprehensive enough. Current test equipment usually generates independent data for conducted interference, radiated interference and immunity tests. There is a lack of unified comprehensive analysis methods between these data, making it difficult to directly judge the overall electromagnetic compatibility performance of industrial power supplies. In addition, existing equipment has deficiencies in the visualization of test results, and the generated test reports are not intuitive enough, making it difficult to provide design engineers with targeted optimization suggestions.

[0008] In view of the above problems, there is an urgent need for an efficient and integrated electromagnetic compatibility test system that can cover multiple dimensions of electromagnetic compatibility testing of industrial control power supplies and support dynamic load adjustment functions to truly restore the working state of industrial control power supplies. The system should combine frequency domain and time domain joint analysis technology to fully capture the spectral characteristics of interference signals and their impact on the dynamic response of power supplies. In addition, the system must also have the ability to process high-frequency signals in real time to ensure the accuracy and integrity of test data, and generate standardized test results and intuitive visual reports through comprehensive evaluation algorithms.

[0009] Therefore, we urgently need to design electromagnetic compatibility test methods and test systems for industrial control power supplies to solve the above problems. Summary of the invention

[0010] The purpose of the present invention is to provide an electromagnetic compatibility test method and a test system for an industrial control power supply in view of the deficiencies in the prior art, so as to solve the problems raised in the background technology.

[0011] To achieve the above object, the present invention provides the following technical solution: an electromagnetic compatibility test system for an industrial power supply, comprising: Load module: used to simulate various working load characteristics of industrial power supply, including resistive, inductive, capacitive and dynamic load, and realize dynamic adjustment of load resistance or characteristics through MOSFET control circuit; Signal connection module: used to connect the industrial control power supply to the test equipment, including high-frequency shielded cable, standardized interface and grounding module; Electromagnetic interference measurement module: used to measure the conducted interference and radiated interference of industrial control power supply, the module includes: Spectrum analysis module: used to analyze the frequency characteristics of interference signals; Time domain response module: used to capture the transient impact of interference signals on the output of industrial control power supply in real time; Immunity test module: used to inject transient interference and surge signals into industrial control power supplies, support automatic generation of standardized signals, and measure their anti-interference capabilities; Data processing module: used to collect and analyze test data and generate electromagnetic compatibility reports that meet industry standards; Hardware acceleration module: Realizes real-time signal processing through FPGA or DSP, supports time correlation analysis of high-frequency signal analysis and interference response; The system simulates the actual working state of the industrial power supply through the dynamic load module, combines the spectrum analysis module and the time domain response module to jointly analyze the characteristics of the interference signal and the output response of the industrial power supply from the frequency domain and time domain dimensions, and uses hardware acceleration technology to realize real-time processing of high-frequency sampling data.

[0012] It needs to be further explained that the load module includes: Resistive load module: used to simulate the pure resistance characteristics of industrial control equipment; Inductive load module: used to simulate transformer and motor loads; Capacitive load module: used to simulate filter capacitor load; The dynamic load control circuit combines the MOSFET array control circuit with the PWM signal to generate a dynamic load curve that changes over time. The formula is as follows: ; in, is the dynamic load value, is the reference load value, is the coefficient of variation, is the frequency of change.

[0013] It needs to be further explained that the signal connection module includes: High-frequency shielded cable: The shielding effectiveness is not less than 50dB, and the interface adopts the standardized interface BNC or SMA; Grounding module: Reduce common mode interference through grounding shielding design, where the grounding impedance satisfies the formula: ; in, is the ground resistance, is the ground inductance, is the grounding capacitance, is the angular frequency.

[0014] It needs to be further explained that the electromagnetic interference measurement module includes: Conducted interference measurement unit: connects to the line impedance stabilization network to measure the conducted noise signal of the industrial control power supply; Radiated interference measurement unit: Use logarithmic periodic antenna and shielded darkroom to measure the radiated noise signal of industrial control power supply; Spectrum analysis module: Calculate the spectrum distribution of the interference signal through the fast Fourier transform algorithm. The formula is as follows: ; in, is the spectrum data, is the time domain signal, is the number of sampling points; Time domain response module: used to capture the instantaneous changes in output voltage, current or power caused by interference signals. It needs to be further explained that the anti-interference test module includes: Electrical fast transient pulse group signal, in line with IEC61000-4-4 standard; Surge signal, in compliance with IEC61000-4-5 standard; Radio frequency interference signal, in compliance with IEC61000-4-6 standard; The signal waveform is generated by the following formula:

[0015] in, is the interference signal amplitude, is the attenuation factor, is the frequency, is the initial phase.

[0016] It needs to be further explained that the data processing module includes: Comprehensive evaluation algorithm module: used to evaluate the comprehensive electromagnetic compatibility index of industrial control power supply. The formula is as follows: ; in, is a comprehensive evaluation index. For the conducted interference test results, For the radiation interference test results, is the result of the immunity test, the weight coefficient satisfy ; Standard comparison module: compare and analyze the test results with the industry standard limits to generate compliance conclusions; The result visualization module is used to generate spectrum diagrams, waveform diagrams and evaluation reports.

[0017] It should be further explained that the comprehensive evaluation algorithm module further optimizes the weight adjustment method and calculates the optimal weight configuration by the least squares method. The formula is as follows: ; in, is the actual test value, is the expected value.

[0018] It should be further explained that the hardware acceleration module implements real-time signal processing through FPGA and supports the following functions: Real-time processing of 100,000 sampling data per second; Fast Fourier transform (FFT) calculation delay is less than 10 microseconds; Realize the time correlation analysis of disturbance response and output characteristics.

[0019] The present invention also provides a testing method for an industrial control power supply electromagnetic compatibility testing system, comprising the following steps: Set the load parameters of the load module to make the industrial power supply work in a state that simulates the actual operating environment; Connect the industrial control power supply to the electromagnetic interference measurement module and the immunity test module through the signal connection module; Measure and record conducted interference and radiated interference signals; Inject the anti-interference test signal into the industrial control power supply and record the power supply output response before and after the interference; The electromagnetic compatibility test report is generated by combining the frequency domain and time domain joint analysis algorithm through the data processing module.

[0020] It needs further explanation that the electromagnetic compatibility test report includes: Comparison of the spectrum of conducted interference test results with the limit values; Spectral distribution of radiated interference test results; The calculation result of the dynamic change rate of output power in the immunity test is as follows: ; in, is the dynamic rate of change, is the variation of output power with time, .

[0021] Compared with the prior art, the present invention has the following beneficial effects: This technical solution uses modular design to build a complete industrial power supply electromagnetic compatibility test system, covering the comprehensive evaluation of conducted interference, radiated interference and anti-interference performance. The load module's resistance, inductance, capacitance and dynamic load adjustment functions can truly simulate the operating status of the industrial power supply under different working conditions, making the test conditions closer to the actual application scenario and improving the applicability and credibility of the test results. In addition, the system supports internationally accepted electromagnetic compatibility test standards (such as the IEC61000 series) and has good versatility and compatibility.

[0022] This solution innovatively combines the frequency domain and time domain joint analysis methods. The frequency characteristics of the interference signal are captured by the spectrum analysis module, and the time domain response module monitors the dynamic impact of interference on the power supply output in real time, providing the ability to analyze electromagnetic compatibility performance from multiple dimensions. The system uses FPGA or DSP hardware acceleration modules to achieve real-time processing and analysis of high-frequency sampling data, which not only improves the test efficiency, but also ensures the accuracy and real-time nature of the test results, providing reliable support for the performance evaluation of industrial control power supplies in complex electromagnetic environments.

[0023] The test results generated by this technical solution are intuitive and standardized, including spectrum diagrams, dynamic response waveforms and comprehensive evaluation index E, which can clearly show the electromagnetic compatibility performance of industrial control power supplies and provide strong support for product design optimization and quality control. The system has good scalability and can adapt to the testing needs of industrial control power supplies of different power ranges and types. It is widely used in industrial automation, communication equipment, power electronics and other fields, with significant engineering application value and broad market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A system block diagram of the electromagnetic compatibility test system for the industrial control power supply proposed by the present invention; Figure 2 The figure is a flow chart of the electromagnetic compatibility testing method for the industrial control power supply proposed by the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The following combination Figure 1 , Figure 2 With reference to the accompanying drawings and a number of embodiments, specific embodiments of the present invention are described in detail.

[0027] The present invention provides an electromagnetic compatibility test method and a test system for an industrial control power supply. The following describes the implementation of the present invention in detail to facilitate better understanding and application of the present invention.

[0028] Example 1: Conducted interference and radiated interference test of industrial control power supply; Test preparation: Load module: Resistive load: Through a precise resistor network, the resistance is set to 100 ohms to simulate the characteristics of the resistive components inside the industrial control equipment.

[0029] Inductive load: Connect a three-phase motor with a rated power of 200W. The inductive load simulates the characteristics of industrial control equipment such as motors or transformers.

[0030] Capacitive load: Connect a 220μF high-frequency filter capacitor to simulate the filter capacitor characteristics of industrial control equipment.

[0031] Dynamic load: Use MOSFET and PWM signal to control load changes and set it to dynamic change mode. The specific formula is: ; The base load Ohm, frequency of change , amplitude change ratio .

[0032] Signal connection module: Shielded cable: Use high-frequency shielded cable (shielding effectiveness dB), reducing the impact of RF interference on signal acquisition in the test environment.

[0033] Interface design: Use standard BNC interface to connect spectrum analyzer and LISN; the antenna part adopts SMA interface to ensure signal integrity and reliability.

[0034] Grounding module: The test equipment and shielded darkroom are grounded, and the impedance satisfies the following formula: ; in, , , , make sure the grounding resistance is less than 0.1 ohm.

[0035] Conducted interference measurement: The conducted interference signal at the input end of the industrial control power supply is collected through the line impedance stabilization network (LISN).

[0036] Use the spectrum analysis module to perform a fast Fourier transform (FFT) to calculate the frequency content of the interference signal: ; is the number of sampling points, and the analysis range is from 150kHz to 30MHz.

[0037] The test results show that the interference amplitudes at all frequency points are lower than the industry standard.

[0038] Radiated interference measurement: Use a log-periodic antenna to connect to an EMI receiver and place the industrial control power supply in a shielded darkroom; the measurement distance is 3 meters.

[0039] The scanning frequency range is from 30MHz to 1GHz, and the influence of external interference is eliminated through a shielded darkroom.

[0040] The test results show that the peak value of the power supply's radiated interference intensity at 100MHz is 30dBμV / m, which meets the industry limit of 40dBμV / m.

[0041] Example 2: Immunity test; Test preparation: Load setting: Dynamic load: MOSFET controlled load simulates dynamic load characteristics, The specific formula is: Ohm change frequency Hz.

[0042] Signal connection: Use high-frequency shielded cable to connect the immunity test module and the industrial control power input terminal; use isolation coupling circuit to protect the power test equipment from signal impact.

[0043] Interference signal injection: Electrical fast transient pulse group (EFT) test: An EFT generator was used to inject a fast pulse signal that complies with the IEC61000-4-4 standard, with a pulse amplitude of 2 kV and a pulse frequency of 5 kHz.

[0044] Surge test: Use a surge generator to simulate lightning interference, the signal amplitude is 1KV, and the waveform is generated according to the 1.2 / 50μs surge waveform defined in the IEC61000-4-5 standard: ; Among them, the amplitude , attenuation factor .

[0045] Radio frequency interference signal: The radio frequency signal with a frequency range of 150kHz to 80MHz and an interference intensity of 10V / m is injected.

[0046] Time Domain Response Analysis: The time domain response module records the transient response of the voltage waveform when the interference signal is injected; it captures the dynamic fluctuations of the power supply output with a rate of change of less than 2%.

[0047] Result evaluation: The industrial control power supply has no functional failure or abnormal phenomenon under the above interference, and the anti-interference test is qualified.

[0048] Example 3: Data processing and comprehensive evaluation; Test data acquisition: The conducted interference, radiated interference and immunity test data are obtained from the spectrum analysis module and time domain response module of the electromagnetic interference measurement module.

[0049] Conducted interference results: The interference intensity at all frequency points is less than 30dBμV; Radiated interference results: The maximum interference intensity is 35dBμV / m; Immunity response: Maximum output fluctuation is less than 2%.

[0050] Comprehensive evaluation: The comprehensive evaluation module of the data processing module calculates the comprehensive index of electromagnetic compatibility : ; dB, conducted interference result; dB, radiated interference result; ,Immunity test results.

[0051] Comprehensive indicators , in line with industry standard requirements.

[0052] Report generation: The standard comparison module generates compliance conclusions: conducted, radiated interference and immunity all meet IEC standards; The result visualization module generates spectrum diagram, time domain waveform diagram and anti-disturbance response curve.

[0053] Embodiment 4: Application of hardware acceleration module; Accelerated processing: FPGA implements real-time FFT operation, supports 100,000 samples per second, and FFT calculation delay is less than 10 microseconds; Capture transient power supply fluctuations caused by interfering signals in high-frequency sampling environments.

[0054] Time correlation analysis: By comparing the interference injection time with the power output change time, it is confirmed that the response delay of the industrial control power supply under interference is 0.2ms, which meets the real-time requirements.

[0055] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for technical personnel in the field to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An electromagnetic compatibility test system for an industrial power supply, comprising: Load module: used to simulate various working load characteristics of industrial power supply, including resistive, inductive, capacitive and dynamic load, and realize dynamic adjustment of load resistance or characteristics through MOSFET control circuit; Signal connection module: used to connect the industrial control power supply to the test equipment, including high-frequency shielded cable, standardized interface and grounding module; Electromagnetic interference measurement module: used to measure the conducted interference and radiated interference of industrial control power supply, the module includes: Spectrum analysis module: used to analyze the frequency characteristics of interference signals; Time domain response module: used to capture the transient impact of interference signals on the output of industrial control power supply in real time; Immunity test module: used to inject transient interference and surge signals into industrial control power supplies, support automatic generation of standardized signals, and measure their anti-interference capabilities; Data processing module: used to collect and analyze test data and generate electromagnetic compatibility reports that meet industry standards; Hardware acceleration module: Realizes real-time signal processing through FPGA or DSP, supports time correlation analysis of high-frequency signal analysis and interference response; The system is characterized in that the system simulates the actual working state of the industrial control power supply through the dynamic load module, combines the spectrum analysis module and the time domain response module, jointly analyzes the characteristics of the interference signal and the output response of the industrial control power supply from the two dimensions of frequency domain and time domain, and uses hardware acceleration technology to realize real-time processing of high-frequency sampling data.

2. The electromagnetic compatibility test system for industrial power supply according to claim 1, characterized in that: The load module comprises: Resistive load module: used to simulate the pure resistance characteristics of industrial control equipment; Inductive load module: used to simulate transformer and motor loads; Capacitive load module: used to simulate filter capacitor load; Dynamic load control circuit: The MOSFET array control circuit is combined with the PWM signal to generate a dynamic load curve that changes over time. The formula is as follows: ； in, is the dynamic load value, is the reference load value, is the coefficient of variation, is the frequency of change.

3. The electromagnetic compatibility test system for industrial power supply according to claim 1, characterized in that: The signal connection module comprises: High-frequency shielded cable: The shielding effectiveness is not less than 50dB, and the interface adopts the standardized interface BNC or SMA; Grounding module: Reduce common mode interference through grounding shielding design, where the grounding impedance satisfies the formula: ； in, is the ground resistance, is the ground inductance, is the grounding capacitance, is the angular frequency.

4. The electromagnetic compatibility test system for industrial power supply according to claim 1, characterized in that: The electromagnetic interference measurement module comprises: Conducted interference measurement unit: connects to the line impedance stabilization network to measure the conducted noise signal of the industrial control power supply; Radiated interference measurement unit: Use logarithmic periodic antenna and shielded darkroom to measure the radiated noise signal of industrial control power supply; Spectrum analysis module: Calculate the spectrum distribution of the interference signal through the fast Fourier transform algorithm. The formula is as follows: ； in, is the spectrum data, is the time domain signal, is the number of sampling points; Time domain response module: used to capture the instantaneous changes of output voltage, current or power caused by interference signals.

5. The electromagnetic compatibility test system for industrial power supply according to claim 1, characterized in that: The anti-interference test module includes: Electrical fast transient pulse group signal, in line with IEC61000-4-4 standard; Surge signal, in compliance with IEC61000-4-5 standard; Radio frequency interference signal, in compliance with IEC61000-4-6 standard; The signal waveform is generated by the following formula: ； in, is the interference signal amplitude, is the attenuation factor, is the frequency, is the initial phase.

6. The electromagnetic compatibility test system for industrial power supply according to claim 1, characterized in that: The data processing module comprises: Comprehensive evaluation algorithm module: used to evaluate the comprehensive electromagnetic compatibility index of industrial control power supply. The formula is as follows: ； in, is a comprehensive evaluation index. For the conducted interference test results, For the radiation interference test results, is the result of the immunity test, the weight coefficient satisfy ; Standard comparison module: compare and analyze the test results with the industry standard limits to generate compliance conclusions; The result visualization module is used to generate spectrum diagrams, waveform diagrams and evaluation reports.

7. The electromagnetic compatibility test system for industrial power supply according to claim 6, characterized in that: The comprehensive evaluation algorithm module further optimizes the weight adjustment method and calculates the optimal weight configuration by the least squares method. The formula is as follows: ； in, is the actual test value, is the expected value.

8. The electromagnetic compatibility test system for industrial power supply according to claim 1, characterized in that: The hardware acceleration module implements real-time signal processing through FPGA and supports the following functions: Real-time processing of 100,000 sampling data per second; Fast Fourier transform (FFT) calculation delay is less than 10 microseconds; Realize the time correlation analysis of disturbance response and output characteristics.

9. A test method for the electromagnetic compatibility test system of an industrial control power supply according to any one of claims 1 to 8, characterized in that: The following steps are involved: Set the load parameters of the load module to make the industrial power supply work in a state that simulates the actual operating environment; Connect the industrial control power supply to the electromagnetic interference measurement module and the immunity test module through the signal connection module; Measure and record conducted interference and radiated interference signals; Inject the anti-interference test signal into the industrial control power supply and record the power supply output response before and after the interference; The electromagnetic compatibility test report is generated by combining the frequency domain and time domain joint analysis algorithm through the data processing module.

10. The electromagnetic compatibility testing method of industrial power supply according to claim 9, characterized in that: The electromagnetic compatibility test report includes: Comparison of the spectrum of conducted interference test results with the limit values; Spectral distribution of radiated interference test results; The calculation result of the dynamic change rate of output power in the immunity test is as follows: ； in, is the dynamic rate of change, is the variation of output power with time, .

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