Wideband Non-Contact Voltage Detection Method and Device

Abstract

This invention discloses a broadband non-contact voltage detection method and device, belonging to the field of railway signal detection technology. The method includes: constructing a multi-layer PCB coupled probe, using a high CTI board and forming a voltage divider capacitor structure through inner copper foil pattern design. This structure utilizes a first coupling capacitor between the input and output electrodes and a second coupling capacitor between the output and reference electrodes connected in series to form a capacitor voltage divider; constructing an active inverse frequency characteristic filter network with a frequency response complementary to that of the multi-layer PCB coupled probe to form a fluctuating controlled total transfer function; acquiring the charged body signal through the probe and compensating it through the filter network, finally outputting a flat voltage signal. This invention effectively eliminates the frequency distortion and low-frequency attenuation problems of traditional probes when measuring electrical variables, achieving high-fidelity linear acquisition of complex mixed-frequency signals in railways, eliminating the need for manual calibration, and significantly improving the consistency and interchangeability of sensor mass production.

Description

Technical Field

[0001] This invention relates to the field of electrical measurement technology, specifically to a broadband non-contact voltage detection method and device. Background Technology

[0002] In the maintenance and fault diagnosis of railway signaling equipment, non-contact voltage detection technology has been widely used due to its good electrical isolation, high safety, and convenient operation. This technology is usually based on the principle of capacitive coupling. An equivalent coupling capacitor is formed between the sensor probe and the charged body. The alternating voltage on the charged body is coupled to the output terminal through the electric field of the capacitor. After being converted into a voltage signal by the front-end high-impedance amplifier circuit, it is then conditioned and acquired by the subsequent processing circuit.

[0003] China's railway system primarily uses 25Hz phase-sensitive track circuits and 50Hz traction power supply. It also widely employs frequency-shift automatic block signals with carrier frequencies of 1700Hz, 2000Hz, 2300Hz, and 2600Hz, such as the ZPW-2000A system, as well as domestically produced frequency-shift automatic block signal systems with carrier frequencies of 550Hz, 650Hz, 750Hz, and 850Hz. Therefore, the detection equipment must cover a frequency band from 25Hz to 2600Hz or even wider, and be able to linearly and proportionally acquire all frequency components within the band to accurately reconstruct signal characteristics.

[0004] Existing non-contact voltage detection systems mostly employ capacitive coupling-based measurement schemes. After acquiring a weak AC signal via a PCB probe, the signal is sequentially amplified, frequency shaped, and filtered by a front-end amplification stage and a subsequent conditioning circuit. However, this approach has the following drawbacks:

[0005] On the one hand, its amplitude-frequency characteristics are difficult to keep flat in a wide frequency band of 25Hz to 2600Hz. In particular, the signal attenuation is severe in the low frequency band and the signal is relatively amplified in the high frequency band, which leads to the distortion of the amplitude ratio of the acquired mixed signal and fails to truly reflect the energy distribution of the original signal, seriously affecting the accuracy of subsequent analysis.

[0006] On the other hand, the compensation resistor and capacitor values ​​of existing devices are usually large, and are significantly affected by PCB parasitic parameters and component tolerances. This means that each sensor requires manual fine-tuning, making it impossible to achieve SMT automated production. Furthermore, the performance differences between different sensors are large, and they are not interchangeable.

[0007] This invention innovatively employs a PCB compensation capacitor with the same dielectric properties and process deviations as the multilayer PCB coupled probe to construct an active inverse frequency characteristic filter network whose transfer function is strictly complementary to the frequency response of the probe and sampling circuit. This achieves full-pass characteristics without manual adjustment in a wide frequency band from 25Hz to 2600Hz. The integrated collaborative design of this compensation architecture and probe has not yet been disclosed in current non-contact voltage detection devices. Summary of the Invention

[0008] This invention provides a broadband non-contact voltage detection method and device, which solves the technical problems of amplitude-frequency characteristic distortion, severe low-frequency signal attenuation, and poor sensor manufacturing process and interchangeability in the prior art when measuring electrical variables.

[0009] This invention is achieved through the following technical solution:

[0010] In a first aspect, this application provides a broadband non-contact voltage detection method, comprising the following steps:

[0011] Using a high CTI board as the substrate, a voltage divider capacitor structure is formed through the inner copper foil pattern design. The voltage divider capacitor structure includes an input electrode, an output electrode, and a reference electrode. A first coupling capacitor is formed between the input electrode and the output electrode, and a second coupling capacitor is formed between the output electrode and the reference electrode. The first coupling capacitor and the second coupling capacitor are connected in series to form a capacitor voltage divider, thus constructing a multilayer PCB coupling probe.

[0012] By matching the PCB capacitor and RC parameters with the circuit structure that are consistent with the frequency characteristics of the non-contact probe, an active inverse frequency characteristic filter network is constructed that has complementary frequency characteristics to the frequency characteristics of the multilayer PCB coupled probe and sampling circuit.

[0013] The voltage signal of the charged body is non-contactly acquired by the multilayer PCB coupling probe, and the conditioned voltage signal is input to the active inverse frequency characteristic filter network for compensation, and the compensated voltage signal is output.

[0014] A further optimization scheme is that the method further includes: maintaining the capacitance deviation between the first coupling capacitor and the second coupling capacitor within a predetermined range by controlling the predetermined thickness tolerance of the interlayer insulation layer.

[0015] A further optimized solution is that the multilayer PCB coupling probe has a multilayer stacked structure, with the input electrode, output electrode and reference electrode stacked sequentially along the interlayer direction. The input electrode faces the charged body to preferentially couple the target voltage signal, the output electrode is placed between the input electrode and the reference electrode to form a series voltage divider path, and the reference electrode is grounded as a potential reference.

[0016] By controlling the predetermined thickness tolerance of the interlayer insulation layer, the capacitance deviation between the first coupling capacitor and the second coupling capacitor is kept within a predetermined range.

[0017] A further optimized solution is that the steps for constructing the active inverse frequency characteristic filter network specifically include:

[0018] The compensation capacitor is fabricated using the same high CTI board material as the multilayer PCB coupling probe. The capacitance value of the compensation capacitor is matched with the capacitance values ​​of the first coupling capacitor and the second coupling capacitor. An active filter network that complements the transfer function of the sampling circuit is designed in conjunction with the compensation capacitor.

[0019] The further optimized solution also includes the following steps:

[0020] The measured voltage signal is input to the differential amplifier module for amplification via a coupling capacitor in a non-contact manner. After being converted to a single-ended signal by the single-ended conversion module, it is input to the inverse frequency compensation circuit for frequency characteristic correction and then output to the data processing module.

[0021] A further optimization is that, when environmental parameters change, the first coupling capacitor and the second coupling capacitor in the voltage divider capacitor structure change synchronously to maintain a constant voltage division coefficient.

[0022] Secondly, this application provides a broadband non-contact voltage detection device, comprising:

[0023] The multilayer PCB coupling probe is made of high CTI board material. It forms a voltage divider capacitor structure through the inner copper foil pattern design. The voltage divider capacitor structure includes an input electrode, an output electrode and a reference electrode. A first coupling capacitor is formed between the input electrode and the output electrode, and a second coupling capacitor is formed between the output electrode and the reference electrode. The first coupling capacitor and the second coupling capacitor are connected in series to form a capacitor voltage divider.

[0024] An active inverse frequency response filter network, wherein the frequency response of the active inverse frequency response filter network is complementary to the frequency response of the multilayer PCB coupled probe, so as to form a flat total transfer function within a predetermined wide bandwidth.

[0025] A further optimized solution is that the multilayer PCB coupling probe has a multilayer stacked structure, the input electrode is located in the middle layer, the output electrode is located in the inner layer, the reference electrode is located in the outermost layer, and the CTI value of the high CTI board material meets the preset insulation level.

[0026] A further optimization scheme includes a signal processing link, which is sequentially connected to a differential amplifier module, a single-ended conversion module, an active inverse frequency characteristic filter network, and a data processing module. The active inverse frequency characteristic filter network performs frequency compensation on the signal after single-ended conversion.

[0027] A further optimization is that the device is applied to railway signal detection scenarios, and the predetermined wideband covers the power frequency and frequency shift carrier frequency ranges in the railway signaling system.

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] By constructing a multi-layer PCB coupling probe with a voltage divider capacitor structure and combining it with an active inverse frequency characteristic filter network that complements its frequency response, a total transfer function with controlled fluctuations is formed within a predetermined wide frequency band. This effectively eliminates the inherent frequency distortion and low-frequency attenuation problems of traditional capacitive coupling probes, thereby achieving high-fidelity linear acquisition of complex mixed-frequency signals of railways without the need for complex manual calibration, and significantly improving the consistency and interchangeability of sensors in mass production.

[0030] Since the probe voltage divider structure and the filter network are both made using the same high CTI board material and PCB process, their dielectric properties and process deviations change synchronously. This ensures that the frequency response matching degree between the compensation network and the probe is not affected by the process discreteness in mass production. The transfer function fluctuation of a single sensor is ≤±1dB, and the performance deviation between different sensors is ≤5%. They can be directly interchanged without the need for individual calibration. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] In the attached image:

[0033] Figure 1 This is a flowchart of a broadband non-contact voltage detection method provided in an embodiment of this application;

[0034] Figure 2 The multilayer PCB coupled probe sensing electrode design and equivalent circuit diagram provided for the embodiments of this application;

[0035] Figure 3 This is a non-contact voltage detection circuit diagram provided in an embodiment of this application;

[0036] Figure 4 A comparison diagram before and after inverse frequency network compensation provided in the embodiments of this application;

[0037] Figure 5 This is a block diagram of the non-contact voltage detection sensor provided in an embodiment of this application. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0039] First, some of the technical terms used in this application will be explained to help those skilled in the art understand this application.

[0040] CTI: Comparative Tracking Index;

[0041] PCB: Printed Circuit Board;

[0042] SMT: Surface Mount Technology;

[0043] dB: Decibel.

[0044] Firstly, such as Figure 1 As shown, this application provides a broadband non-contact voltage detection method, which includes the following steps.

[0045] Step S1: Select a high CTI board as the substrate, and construct a voltage divider capacitor structure through inner copper foil pattern design to obtain a multi-layer PCB coupling probe.

[0046] Specifically, such as Figure 2 As shown, the voltage divider capacitor structure includes an input electrode, an output electrode, and a reference electrode. Under the action of electric field coupling, a first coupling capacitor Cp is formed between the input electrode and the output electrode, and a second coupling capacitor Cn is formed between the output electrode and the reference electrode. The first coupling capacitor is composed of Cp1 and Cp2 connected in parallel, and the second coupling capacitor is composed of Cn1 and Cn2 connected in parallel. The two are connected in series to form a capacitor voltage divider.

[0047] Cp1 is the first sub-capacitor of the first coupling capacitor, that is, the first coupling capacitor between the input electrode and the output electrode;

[0048] Cp2 is the second sub-capacitor of the first coupling capacitor, that is, the second coupling capacitor between the input electrode and the output electrode;

[0049] Cn1 is the first sub-capacitor of the second coupling capacitor, that is, the first coupling capacitor between the output electrode and the reference electrode;

[0050] Cn2 is the second sub-capacitor of the second coupling capacitor, that is, the second coupling capacitor between the output electrode and the reference electrode;

[0051] Specifically, the voltage divider capacitor structure formed by inner copper foil pattern design refers to the process of etching copper foil to form electrode patterns of a specific shape and layout in the inner copper layer (not the top / bottom layer) of a multi-layer PCB. The input electrode is located between the two output electrodes, and the output electrode is located between the two reference electrodes, so that these electrodes naturally form a series coupling capacitor, which ultimately constitutes a stable voltage divider.

[0052] The term "specific" refers to the fact that the shape, area, and interlayer spacing of the electrodes are precisely defined by the PCB design documents. By controlling the thickness tolerance of the interlayer insulation layer to within ±0.05mm, the capacitance deviation between the first and second coupling capacitors is ensured to be ≤5%, thereby achieving quantifiable and reproducible parameters.

[0053] "Stability" refers to using high CTI boards to solidify the partial pressure ratio into a geometric dimension function, so that Cp and Cn drift synchronously when temperature or humidity changes, ensuring that the partial pressure coefficient remains constant, thereby achieving performance deviation control of ≤5% in environments of -40℃ to 85℃ and in mass production.

[0054] Step S2: By matching the PCB capacitors and RC parameters with the circuit structure to match the frequency characteristics of the non-contact probe, an active inverse frequency characteristic filter network is constructed that complements the frequency characteristics of the multi-layer PCB coupled probe and sampling circuit. Since the compensation capacitor and probe use the same high CTI board material, their temperature coefficients and capacitance deviations remain consistent, eliminating compensation errors caused by component discreteness and improving the interchangeability of mass-produced products.

[0055] Specifically, the compensation capacitor is fabricated using the same high CTI board material as the multilayer PCB coupled probe. Through design of the RC parameters, the frequency response of the filter network is made strictly complementary to the frequency response of the probe and sampling circuit, thus forming a flat total transfer function with fluctuations ≤ ±1dB within a wide frequency band of 25Hz to 2600Hz. The compensation capacitance value is strictly matched to the first and second coupling capacitors of the probe. RC parameters include the compensation capacitor having the same capacitance value as the probe capacitor, and the feedback resistor being twice the bias resistor. Strict complementarity means the transfer function is the reciprocal of the probe's transfer function.

[0056] Step S3: The voltage signal of the charged body is non-contactly acquired through a multi-layer PCB coupling probe. The conditioned voltage signal is input to an active inverse frequency characteristic filter network for compensation, and the compensated voltage signal is output. Further, the voltage signal is first input to a differential amplifier module for amplification, then converted to a single-ended signal by a single-ended conversion module, and then input to an active inverse frequency characteristic filter network for compensation. The compensated voltage signal is output to a data processing module to complete the signal conditioning and digitization preparation.

[0057] In one embodiment, the CTI value of the high CTI board meets the preset insulation class; specifically, the CTI value of the high CTI board is not less than 600, in order to meet the high insulation requirements of the railway site.

[0058] In one embodiment, the multilayer PCB coupling probe has a multilayer stacked structure, with the input electrode located in the inner layer, the output electrode in the middle layer, and the reference electrode in the outermost layer; specifically, the multilayer PCB coupling probe has a 5-layer stacked structure. The output electrodes are located in the 2nd and 4th layers, the input electrode is located in the 3rd layer, and the reference electrodes are located in the 1st and 5th layers. That is, the input electrode is located between the two output electrodes, and the output electrode is located between the two reference electrodes. By controlling the thickness tolerance of the interlayer insulating layer to within ±0.05mm, the capacitance deviation between the first coupling capacitor and the second coupling capacitor is ≤5%, thereby controlling production costs while ensuring stability.

[0059] In one embodiment, the first coupling capacitor Cp serves as the input channel for the sensing signal, converting the alternating voltage on the charged body into electric field coupling, which determines the probe's pickup efficiency for the target voltage.

[0060] A capacitive voltage divider is used to provide a stable voltage division ratio and compensate for environmental drift. The voltage division ratio is determined by geometric dimensions such as electrode area and insulation layer thickness. When temperature and humidity change, Cp and Cn drift synchronously, and the voltage division ratio remains constant, thus ensuring high accuracy of probe sensing, self-compensation for temperature drift, and interchangeability in mass production.

[0061] In a voltage divider capacitor structure, the first and second coupling capacitors change synchronously with environmental parameters such as temperature and humidity, maintaining a constant voltage division coefficient. Considering the large temperature and humidity fluctuations in railway signal detection scenarios, and leveraging the low and uniform rate of change of the dielectric constant of high-CTI substrate materials with environmental variations, the voltage division ratio is determined solely by geometric dimensions such as electrode area and insulation layer thickness. This ensures performance deviation ≤5% in environments ranging from -40℃ to 85℃, meeting the stringent requirements of railway sites.

[0062] Specifically, because the multilayer PCB coupling probe uses a high CTI board with a CTI value of not less than 600 as the substrate, the dielectric constant of this material changes very little and uniformly with temperature and humidity. Simultaneously, the area of ​​the input electrode, output electrode, and reference electrode, as well as the thickness of the interlayer insulation layer, are precisely controlled through the inner copper layer pattern design, ensuring that the initial capacitance deviation between the first coupling capacitor Cp and the second coupling capacitor Cn is ≤5%. When temperature or humidity changes, the dielectric constant of the high CTI board and the insulation layer thickness change slightly and synchronously, causing the capacitance values ​​of the first coupling capacitor Cp and the second coupling capacitor Cn to drift synchronously in the same proportion. The voltage division ratio (Cp / (Cp+Cn)) is determined only by the geometric dimensions such as the electrode area and the insulation layer thickness, thus maintaining a constant voltage division coefficient. This ensures the probe's sensing accuracy and interchangeability under different environmental conditions. Specifically, the voltage divider capacitor structure formed through the inner copper layer pattern design refers to etching copper foil in the inner copper layer of the multilayer PCB to form electrode patterns of a specific shape and layout, naturally creating series coupling capacitors between these electrodes, ultimately forming a stable voltage divider.

[0063] In one embodiment, when constructing the active inverse frequency characteristic filter network, the compensation capacitor is made using the same high CTI board material as the multilayer PCB coupled probe. Since the compensation capacitor and the probe capacitor are manufactured using the same materials and processes, their temperature coefficients and capacitance deviations remain consistent, allowing the capacitance value of the compensation capacitor to precisely match the capacitance values ​​of the first and second coupling capacitors. This design utilizes the consistency of PCB process parameters to eliminate compensation errors caused by component discreteness, thereby maintaining the stability of the compensation effect over a wide temperature range and significantly improving the interchangeability of mass-produced products.

[0064] Specifically, the capacitance of the compensation capacitor is strictly equal to the capacitance of the first coupling capacitor and the second coupling capacitor, and the ratio of the bias resistor to the feedback resistor in the filter network is 1:2, making the transfer function of the filter network strictly the reciprocal of the transfer function of the probe and sampling circuit. An active filter network is designed that complements the transfer function of the sampling circuit by combining the compensation capacitor.

[0065] Specifically, the circuit principle of non-contact voltage detection is as follows: Figure 3As shown: The two input signals are capacitively coupled to external conductors through coupling capacitors (i.e., input isolation capacitors) formed by specific inner layer electrodes designed in the PCB board. This induces a voltage divider signal on the electrodes, which then enters the differential amplifier module. During this process, because the non-inverting input of the op-amp is grounded, an equipotential virtual ground is formed at the connection point with the inverting input resistor. Crucially, C5, used in the all-pass compensation filter network, must be manufactured using the exact same PCB board structure and process as this input coupling capacitor, ensuring that its capacitance value is strictly equal and that it possesses consistent temperature and humidity drift characteristics. This design utilizes the inherent consistency of the PCB process to achieve precise automatic matching of circuit parameters, thus eliminating the tedious manual adjustment steps required by traditional designs using high-precision adjustable capacitors.

[0066] In one embodiment, the coupling electrodes employ a multilayer PCB stack-up design, and the sensing probe is equivalent to a voltage divider formed by the series connection of the first coupling capacitor Cp and the second coupling capacitor Cn. The transfer function formula for the front-end input is derived as follows:

[0067] Equation (1)

[0068] In the formula, The transfer function of the front-end probe and sampling circuit; For complex frequencies, The value of the sampling resistor. This is the capacitance value of the probe coupling capacitor;

[0069] As shown in equation (1), the signal attenuates significantly with frequency changes (attenuating by 20 dB / dec in the low-frequency band). Therefore, this invention designs an active inverse frequency characteristic filter network, whose transfer function is:

[0070] Equation (2)

[0071] In the formula, This is the transfer function of the back-end active filter compensation network;

[0072] When equation (2) is cascaded in the back-end circuit, the overall transfer function of the entire circuit is then... for:

[0073] Equation (3)

[0074] As shown in equation (3), the signal is independent of the frequency ω, and the all-pass characteristic is physically realized. Experimental results show that the output is severely attenuated with frequency before the compensation network is added, but after the network is added, the output is flat and has no attenuation effect across the entire frequency band.

[0075] To achieve the above-mentioned all-pass transfer function, it is necessary to ensure that the values ​​of key passive components in the circuit satisfy strict symmetry constraints. The specific parameter relationships are as follows:

[0076] Equation (4)

[0077] In the formula, C1 is the first input coupling capacitor, C2 is the second input coupling capacitor, C3 is the third input coupling capacitor, C4 is the fourth input coupling capacitor, and C5 is the all-pass compensation capacitor; the capacitance values ​​of the five are strictly equal and are uniformly denoted as C; R1 is the first bias resistor, R5 is the second bias resistor, and R9 is the third bias resistor; the resistance values ​​of the three are strictly equal and are uniformly denoted as R; R10 is the feedback multiplier resistor, and its resistance value is twice the above common resistance value R.

[0078] Experimental results show that, Figure 4 As shown, without inverse frequency network compensation, the curve is steep and the output will be severely attenuated with frequency changes. However, with inverse frequency network compensation, the amplitude fluctuation across the entire frequency band is ≤±1dB, the curve is flat, and the output is not affected by frequency changes.

[0079] Figure 4 (a) shows the frequency response waveform without inverse frequency network compensation;

[0080] Figure 4 (b) shows the frequency response waveform after adding inverse frequency network compensation;

[0081] Secondly, this application also provides a broadband non-contact voltage detection device, including a multilayer PCB coupled probe and an active inverse frequency characteristic filter network.

[0082] The multilayer PCB coupling probe is made of high CTI board material, and its voltage divider capacitor structure is formed by the inner copper foil pattern design.

[0083] An active inverse frequency characteristic filter network is connected in series or via feedback to a multilayer PCB coupled probe. Its frequency response is complementary to that of the multilayer PCB coupled probe, so as to form a flat total transfer function within a predetermined wide bandwidth.

[0084] In one embodiment, the multilayer PCB coupling probe has a multilayer stacked structure, with the input electrode located in the inner layer, the output electrode located in the middle layer, and the reference electrode located in the outermost layer. The CTI value of the high CTI board material meets the preset insulation level.

[0085] In one embodiment, the device further includes a signal processing link, which is sequentially connected to a differential amplifier module, a single-ended conversion module, an active inverse frequency characteristic filter network, and a data processing module. For example... Figure 5 As shown in the diagram, the non-contact voltage detection sensor structure provided in this application includes a multilayer PCB coupled probe, an active inverse frequency characteristic filter network, a differential amplifier module, a single-ended conversion module, and a data processing module. The modules are connected in sequence to form a complete signal processing link.

[0086] The specific configurations and functions of each module in the signal processing chain are as follows:

[0087] The differential amplifier module is used to differentially amplify the two input voltage signals and suppress common-mode interference.

[0088] A single-ended conversion module is used to convert two differential signals into a single signal output.

[0089] An active inverse frequency characteristic filter network is used to select appropriate parameters and design an "inverse frequency characteristic" compensation network. Its transfer function is exactly equal to the reciprocal of the front-end transfer function. It is cascaded with the front-end network to form an all-pass filter, which accurately cancels frequency-dependent distortion.

[0090] The data processing module is used to amplify, shape, and process the filtered signal before outputting it.

[0091] In one embodiment, the device provided in this application is applied to railway signal detection scenarios. It addresses the detection requirements of mixed signals from railway 25Hz phase-sensitive track circuits, 50Hz traction power supplies, and frequency-shifted carrier frequencies of 550Hz, 650Hz, 750Hz, 850Hz, 1700Hz, 2000Hz, 2300Hz, and 2600Hz, with a predetermined wideband covering all of the aforementioned frequency ranges. An active inverse frequency characteristic filter network forms a flat total transfer function with fluctuations ≤±1dB within the 25Hz to 2600Hz wideband, effectively eliminating the inherent low-frequency attenuation and high-frequency amplification distortion caused by traditional capacitively coupled probes, accurately restoring the signal energy distribution, and ensuring accurate acquisition of complex mixed signals, meeting the detection requirements of 25Hz phase-sensitive track circuits, domestically produced frequency-shifted systems, and the ZPW-2000A system.

[0092] Thirdly, embodiments of this application also provide a readable storage medium.

[0093] The present application has a readable storage medium storing a broadband non-contact voltage detection program, wherein when the broadband non-contact voltage detection program is executed by a processor, it implements the steps of the broadband non-contact voltage detection method as described above.

[0094] The method implemented when the broadband non-contact voltage detection program is executed can be referred to in various embodiments of the broadband non-contact voltage detection method of this application, and will not be repeated here.

[0095] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0096] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A broadband non-contact voltage detection method, characterized in that, Includes the following steps: Using a high CTI board as the substrate, a voltage divider capacitor structure is formed through the inner copper foil pattern design. The voltage divider capacitor structure includes an input electrode, an output electrode, and a reference electrode. A first coupling capacitor is formed between the input electrode and the output electrode, and a second coupling capacitor is formed between the output electrode and the reference electrode. The first coupling capacitor and the second coupling capacitor are connected in series to form a capacitor voltage divider, thus constructing a multilayer PCB coupling probe. By matching the PCB capacitor and RC parameters with the circuit structure that are consistent with the frequency characteristics of the non-contact probe, an active inverse frequency characteristic filter network is constructed that has complementary frequency characteristics to the frequency characteristics of the multilayer PCB coupled probe and sampling circuit. The voltage signal of the charged body is non-contactly acquired by the multilayer PCB coupling probe, and the conditioned voltage signal is input to the active inverse frequency characteristic filter network for compensation, and the compensated voltage signal is output.

2. The broadband non-contact voltage detection method according to claim 1, characterized in that, The method further includes: maintaining the capacitance deviation between the first coupling capacitor and the second coupling capacitor within a predetermined range by controlling the predetermined thickness tolerance of the interlayer insulating layer.

3. The broadband non-contact voltage detection method according to claim 2, characterized in that, The multilayer PCB coupling probe has a multilayer stacked structure, with the input electrode, output electrode and reference electrode stacked sequentially along the interlayer direction. The input electrode faces the charged body to preferentially couple the target voltage signal, the output electrode is placed between the input electrode and the reference electrode to form a series voltage divider path, and the reference electrode is grounded as a potential reference. By controlling the predetermined thickness tolerance of the interlayer insulation layer, the capacitance deviation between the first coupling capacitor and the second coupling capacitor is kept within a predetermined range.

4. The broadband non-contact voltage detection method according to claim 1, characterized in that, The steps for constructing the active inverse frequency response filter network specifically include: The compensation capacitor is fabricated using the same high CTI board material as the multilayer PCB coupling probe. The capacitance value of the compensation capacitor is matched with the capacitance values ​​of the first coupling capacitor and the second coupling capacitor. An active filter network that complements the transfer function of the sampling circuit is designed in conjunction with the compensation capacitor.

5. The broadband non-contact voltage detection method according to claim 1, characterized in that, It also includes the following steps: The measured voltage signal is input to the differential amplifier module for amplification via a coupling capacitor in a non-contact manner. After being converted to a single-ended signal by the single-ended conversion module, it is input to the inverse frequency compensation circuit for frequency characteristic correction and then output to the data processing module.

6. The broadband non-contact voltage detection method according to claim 1, characterized in that, When environmental parameters change, the first coupling capacitor and the second coupling capacitor in the voltage divider capacitor structure change synchronously to maintain a constant voltage division coefficient.

7. A broadband non-contact voltage detection device, characterized in that, include: The multilayer PCB coupling probe is made of high CTI board material. It forms a voltage divider capacitor structure through the inner copper foil pattern design. The voltage divider capacitor structure includes an input electrode, an output electrode and a reference electrode. A first coupling capacitor is formed between the input electrode and the output electrode, and a second coupling capacitor is formed between the output electrode and the reference electrode. The first coupling capacitor and the second coupling capacitor are connected in series to form a capacitor voltage divider. An active inverse frequency response filter network, wherein the frequency response of the active inverse frequency response filter network is complementary to the frequency response of the multilayer PCB coupled probe, so as to form a total transfer function with fluctuation ≤ ±1dB within a predetermined wide bandwidth.

8. The broadband non-contact voltage detection device according to claim 7, characterized in that, The multilayer PCB coupling probe has a multilayer stacked structure, with the input electrode located in the middle layer, the output electrode located in the inner layer, and the reference electrode located in the outermost layer. The CTI value of the high CTI board material meets the preset insulation level.

9. The broadband non-contact voltage detection device according to claim 7, characterized in that, It also includes a signal processing link, which is sequentially connected to a differential amplifier module, a single-ended conversion module, an active inverse frequency characteristic filter network, and a data processing module. The active inverse frequency characteristic filter network performs frequency compensation on the signal after single-ended conversion.

10. The broadband non-contact voltage detection device according to claim 7, characterized in that, The device is applied to railway signal detection scenarios, and the predetermined wideband covers the power frequency and frequency shift carrier frequency range of the railway signaling system.

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