Transient emission test system checking device

Abstract

The utility model relates to the technical field of electromagnetic compatibility testing, and discloses a transient emission test system checking device, a transient emission test system comprises a power supply module, an electronic switch and a follow current resistor network, and the checking device is composed of an inductor and a load resistor which are connected in series; the input end of the electronic switch is connected to the anode output end of the power supply module, the output end of the electronic switch is connected with the input end of the checking device, and the output end of the checking device is connected with the cathode output end of the power supply module; the freewheeling resistor network is bridged between the input end of the electronic switch and the output end of the checking device; when the electronic switch is turned off, the freewheeling resistor network forms a freewheeling loop with the electronic switch, the inductor and the load resistor, and generates a transient pulse for checking the transient emission test system. The beneficial effects are that the technical problem of insufficient stability of the checking device in the prior art is solved, and the stability of the checking device is improved.

Description

Technical Field

[0001] This application relates to the field of electromagnetic compatibility testing technology, and in particular to a transient emission testing system verification device. Background Technology

[0002] In the field of electromagnetic compatibility testing, the stability and measurement accuracy of transient emission test systems are crucial. To ensure their performance, daily inspections and monthly periodic checks are necessary. Given the necessity of periodic checks, the transient emission test system verification device must possess high stability and ease of use to meet daily and periodic verification requirements. Verification devices in related technologies rely on the complete product, whose internal circuitry is complex, and parameters are prone to drift after long-term use, affecting measurement accuracy. For example, the complete product may contain components such as capacitors, switches, and transistors; performance fluctuations or aging of these components can interfere with the generation and measurement of transient pulses. Utility Model Content

[0003] This application provides a transient emission test system verification device, which solves the technical problem of insufficient stability of verification devices in related technologies and achieves the technical effect of improving the stability of verification devices.

[0004] To achieve the above objectives, the main technical solutions adopted in this application include:

[0005] In a first aspect, embodiments of this application provide a transient emission test system verification device. The transient emission test system includes a power module, an electronic switch, and a freewheeling resistor network. The verification device is composed of an inductor and a load resistor connected in series. The input terminal of the electronic switch is connected to the positive output terminal of the power module, the output terminal of the electronic switch is connected to the input terminal of the verification device, and the output terminal of the verification device is connected to the negative output terminal of the power module. The freewheeling resistor network is connected between the input terminal of the electronic switch and the output terminal of the verification device. When the electronic switch is open, the freewheeling resistor network, the electronic switch, the inductor, and the load resistor form a freewheeling loop and generate a transient pulse for verifying the transient emission test system.

[0006] The transient emission test system verification device proposed in this application forms a freewheeling circuit between the freewheeling resistor network, the electronic switch, the inductor, and the load resistor when the electronic switch is off, and generates a transient pulse. By designing independent inductors and load resistors to simulate the inductive load characteristics in actual circuits, interference from non-core components is avoided, which is conducive to generating transient pulses with stable parameters, thereby ensuring the reliability of the verification results.

[0007] Optionally, the power supply voltage of the power module is 13.5V, the resistance of the load resistor is 0.6Ω, and the inductance of the inductor is 50μH.

[0008] The verification device employs a series combination of a 50μH inductor and a 0.6Ω load resistor, accurately simulating the inductive load characteristics of actual automotive electronic circuits. This ensures that the test results reflect the transient interference characteristics under real-world operating conditions. By identifying the inductor and load resistor that directly contribute to transient pulses and making them standard modules, interference from non-core components is avoided. This ensures that transient pulse generation relies solely on highly stable key components, resulting in more stable transient pulses and improving verification accuracy. Furthermore, the verification device provided in this embodiment only requires calibration of the inductor and load resistor, significantly reducing maintenance costs.

[0009] Optionally, the inductor uses an iron-silicon-aluminum magnetic core with a rated current of 50A; the load resistor is a corrugated wire-wound resistor with a rated power of 1500W.

[0010] Among them, the iron-silicon-aluminum magnetic core has high permeability, low loss, and good temperature stability, which can effectively reduce inductive heating and ensure the reliability of the circuit system. The structure of the corrugated wire-wound resistor allows it to withstand higher power. Compared with ordinary wire-wound resistors, the corrugated wire can dissipate more heat in the same volume, which can prevent resistor damage due to overheating.

[0011] Optionally, the verification device is housed inside a stainless steel casing, which has a banana-shaped socket. The input and output terminals of the verification device are electrically connected to the banana-shaped socket, and the output terminal of the electronic switch and the negative output terminal of the power module both use banana plugs that match the banana-shaped socket.

[0012] The stainless steel casing provides robust physical protection for the verification device. It also serves as an excellent electromagnetic shielding material, helping to ensure the proper functioning of the device.

[0013] Optionally, the banana socket is 6mm in diameter, made of pure copper, and supports a maximum current of 50A. The stainless steel shell has uniform heat dissipation mesh on its surface, and the stainless steel shell is made of 304 stainless steel.

[0014] The banana-shaped socket, made of pure copper, boasts excellent conductivity, ensuring a reliable electrical connection between the verification device and the transient emission test system and oscilloscope. Since the verification device generates significant heat during operation, the perforated stainless steel casing allows for even heat dissipation, preventing localized overheating and contributing to the device's performance stability. The banana-shaped socket supports a maximum current of 50A, matching the rated current of the inductor in the verification device, ensuring reliable electrical connection under rated current conditions.

[0015] Optionally, the freewheeling resistor network includes a first branch and a second branch connected in parallel. The first branch is provided with a first resistor, and the second branch is provided with a second resistor. The resistance value of the first resistor is 40Ω, and the resistance value of the second resistor is 50Ω.

[0016] The peak voltage of the transient pulse is the product of the steady-state current in the inductor and the total resistance of the freewheeling circuit. The peak voltage of the transient pulse is controlled by a freewheeling resistor network.

[0017] Optionally, the switching time of the electronic switch is less than the time constant of the freewheeling circuit.

[0018] Optionally, the switching time of the electronic switch is less than or equal to 300 ns, and the switching time of the electronic switch is less than one-seventh of the time constant of the freewheeling circuit.

[0019] The switching time of the electronic switch is much shorter than the time constant of the freewheeling circuit, and the current decay is negligible, ensuring that the voltage peak of the transient pulse is stable at the theoretical value, which is beneficial to optimizing the pulse waveform quality.

[0020] Optionally, the input terminal of the verification device is connected to the first probe of the oscilloscope, and the output terminal of the verification device is connected to the second probe of the oscilloscope to measure the peak voltage and rise or fall time of the transient pulse. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of the transient emission test system verification device provided in the embodiments of this application;

[0023] Figure 2 This is a schematic diagram of the structure of the transient emission test system verification device provided in the embodiments of this application;

[0024] Figure 3 This is a schematic diagram of the oscilloscope measurement results provided in an embodiment of this application. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] In the field of electromagnetic compatibility (EMC) testing, the stability and measurement accuracy of transient emission test systems are crucial. To ensure their performance, daily checks and monthly verifications are necessary. Given the necessity of periodic verification, the transient emission test system verification device must possess high stability and ease of use to meet daily and periodic verification requirements. This verification device relies on the complete product, whose internal circuitry is complex, requiring periodic calibration of multiple components, including capacitors, switches, and transistors. These components are prone to aging over long-term use, leading to drift in measurement parameters that interfere with transient pulse generation and measurement, thus affecting verification accuracy. Furthermore, the verification device is often bulky, costly, and inconvenient to use.

[0027] The verification principle of the transient emission test system is based on the physical phenomenon of transient pulses generated by sudden changes in inductor current. The transient emission test system verification device provided in this application, through analysis of the verification principle, retains only the core components that directly contribute to the transient pulses and removes the non-core components of the original complete product, thereby eliminating the interference of non-core components and ensuring the accuracy and reliability of the verification results.

[0028] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of the transient emission test system verification device provided in an embodiment of this application. Figure 1As shown, the transient emission test system includes a power module, an electronic switch, and a freewheeling resistor network. The verification device consists of an inductor and a load resistor connected in series. The input terminal of the electronic switch is connected to the positive output terminal of the power module, the output terminal of the electronic switch is connected to the input terminal of the verification device, and the output terminal of the verification device is connected to the negative output terminal of the power module. The freewheeling resistor network is connected between the input terminal of the electronic switch and the output terminal of the verification device. When the electronic switch is open, the freewheeling resistor network, the electronic switch, the inductor, and the load resistor form a freewheeling loop and generate a transient pulse for verifying the transient emission test system.

[0029] In this system, when the electronic switch is closed, it is connected in series with the verification device in the power supply circuit of the power module. At the instant the electronic switch opens, an inductor in the verification device generates a transient pulse, which releases energy through a freewheeling circuit. The peak voltage and rise or fall time of the transient pulse can be measured using an oscilloscope to verify the transient emission test system.

[0030] At the instant the electronic switch changes from closed to open, the freewheeling resistor network conducts, forming a freewheeling loop between the freewheeling resistor network, the electronic switch, the series-connected inductor, and the load resistor. The energy stored in the transient pulse is released through this freewheeling loop. The freewheeling resistor network is used to control the voltage peak of the transient pulse, preventing damage to components.

[0031] If the rise or fall time and peak voltage of the transient pulse measured by the oscilloscope meet the preset standards, the verification results of the transient emission test system are considered reliable. The preset standards refer to the pre-defined technical specifications used to evaluate the performance of the transient emission test system. These standards specify the allowable ranges for the peak voltage and rise or fall time of the transient pulse, among other things.

[0032] The power supply module, freewheeling resistor network, and electronic switch are all integrated into the transient emission test system. The freewheeling resistor network and electronic switch are located at the output of the transient emission test system. Typically, the output of the transient emission test system is connected to an external device under test (DUT), and transient voltages are applied to test the DUT's immunity to interference. During the verification of the transient emission test system, the DUT must be disconnected, the output of the electronic switch connected to the input of the verification device, and the negative output of the power supply module connected to the output of the verification device. Since the verification device uses standard inductors and load resistors, it measures the rise or fall time of the transient pulse and the peak voltage to determine if they are within the standard allowable range, thereby verifying whether the transient emission test system meets the performance standards.

[0033] In some embodiments, the power supply voltage of the power module is 13.5V, the resistance of the load resistor is 0.6Ω, and the inductance of the inductor is 50μH.

[0034] Please refer to Figure 2 , Figure 2 This is a schematic diagram of the structure of the transient emission test system verification device provided in an embodiment of this application. Figure 2 As shown, the verification device uses a 50μH inductor and a 0.6Ω load resistor connected in series, which can accurately simulate the inductive characteristics of actual automotive electronic product circuits, ensuring that the test results reflect the transient interference characteristics under real operating conditions. This embodiment analyzes the verification principle and extracts the inductor and load resistor, which directly contribute to transient pulses, into a standard module, avoiding interference from non-core components. This ensures that the generation of transient pulses relies only on highly stable key components, resulting in more stable transient pulses and improving the accuracy of the verification results. The verification device provided in this embodiment only requires calibration of the inductor and load resistor, significantly reducing maintenance costs.

[0035] Transient pulses defined according to industry standards (e.g., ISO 7637-2) specify load parameters. Choosing a series combination of a 50μH inductor and a 0.6Ω resistor aligns with these standards, ensuring global comparability of the test results. Furthermore, using a standard parameter combination (50μH inductor and 0.6Ω resistor) ensures consistency across different laboratories, facilitating compliance verification.

[0036] If the power supply voltage of the power module is 13.5V, then when the electronic switch is off, the steady-state current I of the inductor in the verification device is:

[0037]

[0038] The peak voltage of a transient pulse is the product of the steady-state current in the inductor and the total resistance of the freewheeling circuit. The total resistance of the freewheeling circuit is the sum of the resistance of the freewheeling resistor network and the load resistance.

[0039] In some embodiments, the inductor uses an iron-silicon-aluminum magnetic core with a rated current of 50A; the load resistor is a corrugated wire-wound resistor with a rated power of 1500W.

[0040] Among them, the iron-silicon-aluminum magnetic core has high permeability, low loss, and good temperature stability, which can effectively reduce inductive heating and ensure the reliability of the circuit system. The structure of the corrugated wire-wound resistor allows it to withstand higher power. Compared with ordinary wire-wound resistors, the corrugated wire can dissipate more heat in the same volume, avoiding resistor damage due to overheating.

[0041] In some embodiments, the verification device is housed inside a stainless steel casing, which has a banana-shaped connector. The input and output terminals of the verification device are electrically connected to the banana-shaped connector, and the output terminal of the electronic switch and the negative output terminal of the power module both use banana plugs that match the banana-shaped connector.

[0042] The stainless steel casing provides robust physical protection for the verification device. It can also feature a handle for ease of use. The output terminals of the electronic switch, the negative output terminal of the power module, and the oscilloscope probe can all use a banana-head design for easy electrical connection to the stainless steel casing, with red and black markings distinguishing positive and negative terminals. The stainless steel casing is an excellent electromagnetic shielding material, contributing to the proper functioning of the verification device.

[0043] In some embodiments, the banana socket is 6mm in diameter, made of pure copper, and supports a maximum current of 50A. The stainless steel housing has uniform heat dissipation mesh holes on its surface, and the stainless steel housing is made of 304 stainless steel.

[0044] The banana-shaped connector, made of pure copper, boasts excellent conductivity, ensuring a reliable electrical connection between the verification device and the transient emission test system and oscilloscope. It represents a simple, reliable, and standardized connection method. The 6mm banana-shaped connector and plug are standardized connection elements, allowing the verification device to be easily connected to other devices using the same banana-shaped connector, facilitating measurement work. The banana-shaped connector supports a maximum current of 50A, matching the rated current of the inductor in the verification device, ensuring reliable electrical connection under rated current. 304 stainless steel possesses high strength and hardness, resisting external mechanical impacts, and is corrosion-resistant, rust-resistant, high-temperature resistant, and acid and alkali resistant. Since the verification device generates a significant amount of heat during operation, the heat dissipation mesh on the stainless steel casing ensures uniform heat dissipation, preventing localized overheating and contributing to the stability of the verification device's performance.

[0045] In some embodiments, the freewheeling resistor network includes a first branch and a second branch connected in parallel, the first branch having a first resistor and the second branch having a second resistor, the first resistor having a resistance value of 40Ω and the second resistor having a resistance value of 50Ω.

[0046] Among them, such as Figure 2As shown, the freewheeling resistor network consists of a first branch and a second branch connected in parallel. Therefore, the total equivalent resistance of the freewheeling resistor network is 40 × 50 / (40 + 50) ≈ 22.22 Ω. When the electronic switch switches from closed to open, the freewheeling resistor network provides a freewheeling path for the verification device. The freewheeling circuit includes an inductor, a load resistor, an electronic switch, and the freewheeling resistor network. The total resistance of the freewheeling circuit is the total effective resistance of the freewheeling resistor network plus the resistance in the verification device, i.e., the total resistance of the freewheeling circuit is 22.2 + 0.6 = 22.8 Ω. The peak voltage of the transient pulse is the product of the steady-state current in the inductor and the total resistance of the freewheeling circuit, i.e., the peak voltage of the transient pulse is 22.5 A × 22.8 Ω ≈ 513 V.

[0047] Therefore, by designing a freewheeling resistor network with the first and second branches connected in parallel, it is possible to precisely control the rise or fall time of transient pulses and the voltage peak value.

[0048] In addition, such as Figure 2 As shown, the freewheeling resistor network also includes an internal inductor and an internal capacitor, wherein the inductance of the internal inductor is 5μH and the capacitance of the internal capacitor is 0.1μF.

[0049] In some embodiments, the switching time of the electronic switch is less than the time constant of the freewheeling circuit.

[0050] In some embodiments, the switching time of the electronic switch is less than or equal to 300 ns, and the switching time of the electronic switch is less than one-seventh of the time constant of the freewheeling circuit.

[0051] The switching time of an electronic switch refers to the time required for the electronic switch to go from being on to being completely off. The switching time of an electronic switch is less than or equal to 300 ns, and is less than one-seventh of the time constant of the freewheeling circuit. This means that the switching time of the electronic switch is much smaller than the time constant of the freewheeling circuit, allowing the electronic switch to complete the switching between on and off states in a very short time with negligible current attenuation. Less current attenuation results in more stable rise or fall times of transient pulses and more stable voltage peak values, which helps ensure the accuracy and stability of transient pulse parameter measurements.

[0052] Wherein, the time constant τ of the freewheeling circuit is the ratio of the inductance in the verification device to the total resistance of the freewheeling circuit, that is:

[0053]

[0054] In some embodiments, the preset criteria include: the rise or fall time of the transient pulse is 300ns ± 20%; and the peak voltage of the transient pulse is 500V ± 10%.

[0055] In automotive electronics scenarios, operations such as relay disconnection, motor start / stop, and sudden load drops generate rapid transient pulses. The rise or fall time of these transient pulses is typically on the order of hundreds of nanoseconds, and the peak voltage can reach hundreds of volts. The aforementioned preset standard references the requirements for peak voltage and switching time in GB / T 21437.2-2021. A rise or fall time of 300ns ± 20% and a peak voltage of 500V ± 10% can cover the transient voltage range that typical automotive electronic equipment may withstand. Generally, during the verification process, the average of ten measurements is used as the final verification result to determine whether the final verification result meets the preset standard.

[0056] In some embodiments, the input of the verification device is connected to a first probe of an oscilloscope, and the output of the verification device is connected to a second probe of the oscilloscope to measure the peak voltage and rise or fall time of the transient pulse.

[0057] For example, please refer to Figure 3 , Figure 3 This is a schematic diagram illustrating the measurement results of an oscilloscope provided in an embodiment of this application. Figure 3 As shown, the measurement results show that the transient pulse fall time is 319.4ns and the voltage peak value is 488V, which meets the above preset standard.

[0058] In some embodiments, the oscilloscope used to measure transient pulses must meet the following criteria: bandwidth greater than or equal to 400MHz; sampling rate greater than or equal to 2GS / s; probe attenuation ratio of 10:1 or 100:1; maximum input voltage greater than or equal to 500V; and input impedance greater than or equal to 1MΩ (DC).

[0059] The above standards are set for oscilloscopes in accordance with GB / T 21437.2-2021. Oscilloscopes using these standards can accurately measure the rise or fall time and waveform details of transient pulses. For example, the Tektronix MD034 oscilloscope can be used.

[0060] In some embodiments, the measurement environment requirements for the verification device include: an ambient temperature of 23℃±5℃ and a relative humidity not exceeding 80%.

[0061] Referring to the requirements for the measurement environment in GB / T 21437.2-2021, the ambient temperature during the measurement period should be 23℃±5℃ and the relative humidity should not exceed 80%.

[0062] The transient emission test system verification device provided in this application includes a power supply module, an electronic switch, and a freewheeling resistor network. The verification device consists of an inductor and a load resistor connected in series. The input terminal of the electronic switch is connected to the positive output terminal of the power supply module, the output terminal of the electronic switch is connected to the input terminal of the verification device, and the output terminal of the verification device is connected to the negative output terminal of the power supply module. The freewheeling resistor network is connected between the input terminal of the electronic switch and the output terminal of the verification device. When the electronic switch is open, the freewheeling resistor network, the electronic switch, the inductor, and the load resistor form a freewheeling loop and generate a transient pulse for verifying the transient emission test system. By designing standardized and independent inductors and load resistors to simulate the inductive load characteristics in actual circuits, it is beneficial to ensure the generation of stable transient pulses, thereby ensuring the reliability of the verification results. The verification device provided in this application is low in cost, has good heat dissipation, and low maintenance cost. It can not only verify the voltage peak value of the transient pulse, but also verify the rise or fall time of the transient pulse, providing more comprehensive performance parameter verification.

[0063] Further functional descriptions of the above modules and units are the same as those in the corresponding embodiments described above, and will not be repeated here.

[0064] For ease of description, the above devices are described separately by function as various units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware.

[0065] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0066] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0067] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

[0068] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A verification device for a transient emission test system, characterized in that, The transient emission test system includes a power module, an electronic switch, and a freewheeling resistor network. The verification device consists of an inductor and a load resistor connected in series. The input terminal of the electronic switch is connected to the positive output terminal of the power module, the output terminal of the electronic switch is connected to the input terminal of the verification device, and the output terminal of the verification device is connected to the negative output terminal of the power module. The freewheeling resistor network is connected between the input terminal of the electronic switch and the output terminal of the verification device. When the electronic switch is open, the freewheeling resistor network, the electronic switch, the inductor, and the load resistor form a freewheeling loop and generate a transient pulse for verifying the transient emission test system.

2. The verification device according to claim 1, characterized in that, The power supply module has a supply voltage of 13.5V, the load resistor has a resistance of 0.6Ω, and the inductor has an inductance of 50μH.

3. The verification device according to claim 2, characterized in that, The inductor uses an iron-silicon-aluminum magnetic core with a rated current of 50A; the load resistor is a corrugated wire-wound resistor with a rated power of 1500W.

4. The verification device according to claim 2 or 3, characterized in that, The verification device is housed inside a stainless steel casing, which has a banana-shaped socket. The input and output terminals of the verification device are electrically connected to the banana-shaped socket. The output terminal of the electronic switch and the negative output terminal of the power module both use banana plugs that match the banana-shaped socket.

5. The verification device according to claim 4, characterized in that, The banana socket is 6mm in diameter, made of pure copper, and supports a maximum current of 50A. The stainless steel shell has uniform heat dissipation mesh on its surface and is made of 304 stainless steel.

6. The verification device according to claim 1, characterized in that, The freewheeling resistor network includes a first branch and a second branch connected in parallel. The first branch is provided with a first resistor, and the second branch is provided with a second resistor. The resistance value of the first resistor is 40Ω, and the resistance value of the second resistor is 50Ω.

7. The verification device according to claim 1, characterized in that, The switching time of the electronic switch is less than the time constant of the freewheeling circuit.

8. The verification device according to claim 7, characterized in that, The switching time of the electronic switch is less than or equal to 300 ns, and the switching time of the electronic switch is less than one-seventh of the time constant of the freewheeling circuit.

9. The verification device according to claim 1, characterized in that, The freewheeling resistor network also includes an internal inductor and an internal capacitor, wherein the inductance of the internal inductor is 5μH and the capacitance of the internal capacitor is 0.1μF.

10. The verification device according to claim 1, characterized in that, The input terminal of the verification device is connected to the first probe of the oscilloscope, and the output terminal of the verification device is connected to the second probe of the oscilloscope to measure the peak voltage and rise or fall time of the transient pulse.

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