Human body dynamic potential tester based on capacitance voltage division

Abstract

The present invention relates to a human body dynamic potential tester based on a capacitive voltage divider, comprising: a potential sensor using a coaxial capacitive voltage divider for detecting a potential signal; a signal processing system disposed within the potential sensor for amplifying and filtering the potential signal to obtain a measured value; a data visualization module for visualizing the measured value; a main control module for compensating the measured value and controlling the human body dynamic potential tester as a whole; a power supply module for supplying power to the human body dynamic potential tester; and a housing enclosing the power supply device of the human body dynamic potential tester, the housing being grounded. The present invention is advantageous in eliminating system measurement errors caused by test distance, integrating a signal sampling module within a coaxial high-voltage voltage divider, and thereby reducing environmental noise introduced by signal lines. It is capable of accurately measuring electrostatic dynamic potential and monitoring human body potential in anti-static work areas such as electronic product and pyrotechnic production workshops.

Description

Technical Field

[0001] The present invention relates to the technical field of electrostatic discharge, and in particular to a human body dynamic potential tester based on capacitance voltage division. Background Art

[0002] Electrostatic potential measurement is an integral component of ESD protection engineering and forms the basis for deriving other electrostatic parameters. Accurate measurement of these parameters is essential for both production and ESD protection applications. Existing domestic human body static electricity testers suffer from issues such as drifting readings and low measurement accuracy, making them difficult to meet the requirements for high-precision ESD potential testing.

[0003] Currently, electrostatic potential testers manufactured domestically and internationally operate on different principles, resulting in significant discrepancies in measurement results and poor test reproducibility. These instruments struggle to accurately measure the peak value and voltage time-domain waveform of the electrostatic potential and are significantly affected by the tester. Consequently, they cannot simultaneously meet the requirements for upper frequency limits, low-range accuracy, and high-voltage linearity. Electrostatic potential measurements also suffer from zero drift and gap discharge, resulting in poor stability and low measurement accuracy. Summary of the Invention

[0004] In order to solve the technical problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a human body dynamic potential tester based on capacitive voltage division, which is conducive to reducing the environmental noise introduced by the signal line, and can realize the accurate measurement of electrostatic dynamic potential, and monitor the human body potential in anti-static work areas such as electronic product and pyrotechnic production workshops.

[0005] To achieve the above-mentioned object of the invention, the present invention provides a human body dynamic potential tester based on a capacitive voltage divider, comprising:

[0006] Potential sensor, using a coaxial capacitive voltage divider, is used to detect potential signals;

[0007] A signal processing system is provided in the potential sensor and is used to amplify and filter the potential signal to obtain a measurement value;

[0008] Data visualization module for visualizing measurement values;

[0009] Main control module, used to compensate the measured values ​​and control the whole body dynamic potential tester;

[0010] A power module is used to supply power to the human body dynamic potential tester;

[0011] The shell encloses the power supply device of the human body dynamic potential tester, and the shell is grounded.

[0012] According to one aspect of the present invention, the potential sensor comprises:

[0013] The outer metal sleeve is used as the input terminal for measuring the static voltage of the human body;

[0014] An insulating medium is provided between the inner metal sleeve and the outer metal layer to form a distributed capacitor;

[0015] The signal sampling module is arranged inside the inner metal sleeve.

[0016] According to one aspect of the present invention, a coaxial capacitive voltage divider model is simulated and calculated using the electromagnetic field simulation software ANSYS. The irregularly shaped parts of the model that cannot be calculated according to the formula are simulated, the theoretical capacitance values ​​of the high-voltage arm and the low-voltage arm are calculated, and the capacitive voltage divider ratio is obtained.

[0017] According to one aspect of the present invention, ANSYS software is used to analyze the length of the outer electrode plate, the thickness of the dielectric, the radius of the outer electrode plate, the capacitance value, and the voltage divider ratio to obtain structural data of the potential sensor.

[0018] According to one aspect of the present invention, the shell includes a shell surface and a shell frame, the shell surface is anti-statically sprayed after chemical conductive oxidation treatment, and an elastic conductor pad is provided at the junction of the shell surface and the shell frame.

[0019] According to one aspect of the present invention, it also includes:

[0020] Zero calibration circuit, used to zero the input signal and amplifier before measurement.

[0021] According to one aspect of the present invention, the signal processing system is equipped with a signal input protection circuit, and a protection ring is provided on the surface of the signal input protection circuit, which is directly connected to the protection buffer through a pressure relief shape connection.

[0022] According to one aspect of the present invention, the main control module is a high-performance 32-bit Cortex-M3 core SOC microcontroller STM32F103C8T6 of ARMv7 architecture, with a system clock frequency of 72MHz, a 64K Byte flash memory controller and a 20KByte SRAM.

[0023] According to one aspect of the present invention, the data visualization module is a LabVIEW host computer or an LED display screen.

[0024] According to one aspect of the present invention, the main control module uses a correlation analysis method to screen correlation variables that affect the output, establishes a measurement value compensation model, and compensates the measurement value.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] According to the solution of the present invention, the human body dynamic potential tester based on capacitive voltage divider includes a potential sensor, a signal processing system, a data visualization module, a main control module, a power supply module and a casing. The potential sensor adopts a coaxial capacitive voltage divider, combined with the measurement principle of capacitive voltage divider, ground shielding-voltage input, which is conducive to eliminating the system measurement error caused by the test distance. The signal sampling module is integrated inside the coaxial high-voltage voltage divider, which is conducive to reducing the environmental noise introduced by the signal line, and can realize the accurate measurement of electrostatic dynamic potential, and monitor the human body potential in anti-static work areas such as electronic product and pyrotechnic production workshops.

[0027] According to one aspect of the present invention, a quasi-static field model is established using electromagnetic field simulation software Ansoft to simulate a coaxial capacitive voltage divider and solve for the capacitor. When calculating field problems, distributed parameters are used instead of lumped parameters, and the lumped capacitance is simulated based on the calculated dielectric constant. This avoids design limitations imposed by finished sensors, reduces production costs, simplifies system architecture, and achieves advantages such as stable axial characteristics, low dielectric loss, and a wide frequency range.

[0028] According to one solution of the present invention, the signal sampling module is integrated within a coaxial high-voltage divider to reduce environmental noise introduced by the signal lines. A modular design separates digital and analog circuits, employs a guard ring design, and grounds the sampling module with a metal shielding box. A combination of various wiring optimization strategies reduces interference. This also creates a zero electric field between the measurement system and the object being measured, addressing issues such as electrostatic potential drift and gap discharge.

[0029] According to one solution of the present invention, a software for collecting, processing and storing human body dynamic potential data is designed based on the collaboration of LabVIEW, embedded hardware chips and high-precision AD. It realizes the real-time display and storage of electrostatic potential peak and dynamic time domain waveform, and can cooperate with other software to realize the calculation of parameters and related characteristics, facilitating subsequent research and analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0031] Figure 1 The figure schematically shows the overall design block diagram of a human body dynamic potential tester based on capacitive voltage division provided by an embodiment of the present invention;

[0032] Figure 2 Schematically showing the structure of the potential sensor in an embodiment of the present invention;

[0033] Figure 3 Schematically shows a schematic diagram of the PCB structure of the signal input protection ring circuit in an embodiment of the present invention;

[0034] Figure 4 Schematically shows a partial circuit principle diagram of the main control module in an embodiment of the present invention;

[0035] Figure 5 The following schematically shows a collection environment diagram in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The description of the embodiments in this specification should be combined with the corresponding drawings, which should be considered a complete part of this specification. In the drawings, the shapes and thicknesses of the embodiments may be exaggerated and indicated for simplicity or convenience. Furthermore, the various structural components in the drawings will be described separately. It is worth noting that components not shown in the drawings or not described in words are known to those of ordinary skill in the art.

[0037] The description of the embodiments herein and any references to directions and orientations are for ease of description only and are not to be construed as limiting the scope of the present invention. The following description of the preferred embodiments may involve combinations of features, which may exist independently or in combination. The present invention is not specifically limited to the preferred embodiments. The scope of the present invention is defined by the claims.

[0038] like Figure 1 As shown, the present invention is a human body dynamic potential tester based on capacitance voltage division, comprising:

[0039] Potential sensor, using a coaxial capacitive voltage divider, is used to detect potential signals;

[0040] A signal processing system is provided in the potential sensor and is used to amplify and filter the potential signal to obtain a measurement value;

[0041] Data visualization module for visualizing measurement values;

[0042] Main control module, used to compensate the measured values ​​and control the whole body dynamic potential tester;

[0043] A power module is used to supply power to the human body dynamic potential tester;

[0044] The shell encloses the power supply device of the human body dynamic potential tester, and the shell is grounded.

[0045] In this embodiment, a human body dynamic potential tester based on capacitive voltage divider includes a potential sensor, a signal processing system, a data visualization module, a main control module, a power supply module and a casing. The potential sensor adopts a coaxial capacitive voltage divider, combined with the measurement principle of capacitive voltage divider, ground shielding-voltage input, which is conducive to eliminating the system measurement error caused by the test distance. The signal sampling module is integrated inside the coaxial high-voltage voltage divider, which is conducive to reducing the environmental noise introduced by the signal line, and can realize the accurate measurement of electrostatic dynamic potential, and monitor the human body potential in anti-static work areas such as electronic product and pyrotechnic production workshops.

[0046] like Figure 2 As shown, in one embodiment of the present invention, preferably, the potential sensor includes:

[0047] The outer metal sleeve is used as the input terminal for measuring the static voltage of the human body;

[0048] An insulating medium is provided between the inner metal sleeve and the outer metal layer to form a distributed capacitor;

[0049] The signal sampling module is arranged inside the inner metal sleeve.

[0050] In this embodiment, the potential sensor adopts a coaxial capacitive voltage divider with an outer metal sleeve as the input end for measuring the electrostatic voltage of the human body. An insulating medium is provided between the inner metal sleeve and the outer metal to form a distributed capacitance of less than 10pf. The signal sampling module is placed inside the capacitor to perform signal processing, reduce errors, and obtain better data results.

[0051] In one embodiment of the present invention, preferably, the coaxial capacitive voltage divider model is simulated and calculated using the electromagnetic field simulation software ANSYS, the irregularly shaped parts of the model that cannot be calculated according to the formula are simulated, the theoretical capacitance values ​​of the high-voltage arm and the low-voltage arm are calculated, and the capacitive voltage divider ratio is obtained.

[0052] In one embodiment of the present invention, preferably, ANSYS software is used to analyze the length of the outer electrode plate, the thickness of the dielectric, the radius of the outer electrode plate, the capacitance value and the voltage divider ratio to obtain the structural data of the potential sensor.

[0053] In this embodiment, the electromagnetic field simulation software ANSYS is used to simulate the coaxial capacitive voltage divider model, simulate the irregularly shaped parts in the model that cannot be calculated according to the formula, calculate the theoretical capacitance values ​​of the high-voltage arm and the low-voltage arm, and solve the capacitive voltage divider ratio. The "optimization" function of ANSYS is used to analyze the length of the outer plate, the thickness of the dielectric, the radius of the outer plate, the capacitance value and the voltage divider ratio to design a reasonable sensor structure. When calculating the problem of the field, it is difficult to use lumped parameters, so distributed parameters are used instead of lumped parameters. The lumped capacitance is simulated based on the calculated dielectric constant. This avoids design restrictions brought by the finished sensor, reduces production costs, simplifies the system structure, and meets the advantages of stable axial characteristics, low dielectric loss, and a wide frequency range.

[0054] In one embodiment of the present invention, preferably, the shell includes a shell surface and a shell frame, the shell surface is anti-statically sprayed after chemical conductive oxidation treatment, and an elastic conductor pad is provided at the junction of the shell surface and the shell frame.

[0055] In this embodiment, the electrostatic discharge immunity is eliminated by well grounding the housing, and an elastic conductive pad is provided at the junction of the housing surface and the housing frame to further enhance electromagnetic shielding.

[0056] In one embodiment of the present invention, preferably, it further includes:

[0057] Zero calibration circuit, used to zero the input signal and amplifier before measurement.

[0058] In this embodiment, by designing a zero calibration circuit, the input signal Vs is adjusted to zero before measurement, and then the amplifier is zeroed before data measurement is performed, which is conducive to ensuring the accuracy and reliability of the measurement value.

[0059] like Figure 3 As shown in one embodiment of the present invention, preferably, the signal processing system is configured with a signal input protection circuit, and a protection ring is provided on the surface of the signal input protection circuit, which is directly connected to the protection buffer through a pressure relief shape connection.

[0060] In this embodiment, for a high input impedance signal measurement circuit, EMI and RFI can interfere with the signal, especially when the signal strength is low or the transmission line is long. These noises are coupled into the operational amplifier through various pathways, and the PCB traces of the signal input protection circuit can become antennas and pick up EMI signals. A guard ring is provided on the surface of the signal input protection circuit, which is directly connected to the protection buffer via a pressure relief shape connection. Since the guard ring is a low impedance node, it is equivalent to creating an equipotential area in the input circuit portion, preventing external leakage current from flowing into the input terminal, while interrupting capacitive coupling. All displacement currents from the interference source are diverted to the low impedance source, avoiding electrostatic interference. In order to obtain the best input protection effect, the guard ring should completely and tightly wrap the input path to reduce the input surface area and stray input capacitance, minimizing the impact of electrostatic coupling and ionization strikes.

[0061] In accordance with the electromagnetic compatibility requirements of GJB 3947A-2009, this design implements technical measures such as grounding, shielding, bonding, and isolation. In circuit design, rational layout is employed to minimize high-speed line lengths. For the power supply, thicker traces are used to minimize power supply resistance. Each printed circuit board undergoes individual filtering at power input to minimize inherent power supply interference and prevent crosstalk. Shielded grounding is used for sensitive signals to minimize external interference.

[0062] In one embodiment of the present invention, the main control module is preferably a high-performance 32-bit Cortex-M3 core SOC microcontroller STM32F103C8T6 of the ARMv7 architecture, with a system clock frequency of 72MHz, a 64KB flash memory controller and a 20KB SRAM. It has a built-in 7-channel DMA controller, 37 fast I / O ports, 3 USARTs, 2 IICs and other 9 communication interfaces. The system hardware circuit design is simple and can meet the use requirements of this system

[48] . Figure 4 This is the minimum system schematic. The core board uses a 3.3V power supply voltage. In order to reduce noise interference, a 0.1μf filter capacitor is placed near the power pin; the main clock is generated by an external 8MHz crystal oscillator, and the crystal oscillator is connected in parallel with an 18pF external capacitor to ensure normal oscillation; the system reset method uses two methods: automatic reset on power on and reset by button; the chip core integrates two download and debugging interfaces, JTAG and SWD. In order to save layout space, this system uses a four-wire SW-DP interface; the minimum system has two buttons as range control switches, the SPI bus performs read and write conversion with the high-speed AD, the IIC bus communicates data with the temperature and humidity module, one USART1 is connected to the display screen, and one USART2 converts the TTL level to 232 level for data communication with the host computer, the 5-wire cable interface and the coaxial voltage divider realize signal transmission, and multiple I / O ports are reserved for functional expansion.

[0063] In one embodiment of the present invention, preferably, the data visualization module is a LabVIEW host computer or an LED display screen.

[0064] In this embodiment, both the LED display and the LabVIEW host computer can realize data visualization. The lower computer transmits the digital signal to the LED display and the host computer software at high speed to realize data analysis, dynamic display of time domain waveform, and storage and other functions.

[0065] In one embodiment of the present invention, preferably, the main control module uses a correlation analysis method to screen correlation variables that cause output influence, establishes a measurement value compensation model, and compensates the measurement value.

[0066] In this embodiment, the factors affecting the measurement stability are preliminarily analyzed through experiments, and a constant temperature and a variable temperature environment are established, such as Figure 5 The results show that the correlation analysis method is used to screen the correlation variables that affect the output and establish a temperature compensation model. First, the data is averaged and the temperature characteristics of the processed data are tested. A constant temperature point is set every 5°C from 0°C to 35°C. The output data is collected and pre-processed to remove some defective data points. A high-order fitting constant temperature model is established. The polynomial fitting method is used to establish the constant temperature model, where the relationship between the zero offset output A0 and the constant temperature point Ti is: Where Ki is the fitting coefficient and n is the fitting order. The formula is used to perform a multi-order fit on the mean point of the test data, calculate the sum of squares of the residuals of different orders, and finally fit the temperature compensation parameters for the constant temperature environment. The same steps are used to collect the output under the variable temperature environment. The constant temperature and humidity chamber is set to different temperature change rates of 0.5℃ / min and 1℃ / min. The voltage divider output change curve is tested at different temperature change rates. A temperature compensation model is established based on the correlation, and the temperature compensation parameters for the variable temperature environment are fitted. Based on the main control module, the temperature and humidity parameters of the human body dynamic potentiometer are compensated, and the communication with the LabVIEW host computer in the compensation system and the overall test system are completed. This allows the test model to be modified and the test accuracy to be improved.

[0067] The present invention discloses a human body dynamic potential tester based on a capacitive voltage divider, comprising: a potential sensor using a coaxial capacitive voltage divider for detecting a potential signal; a signal processing system disposed within the potential sensor for amplifying and filtering the potential signal to obtain a measured value; a data visualization module for visualizing the measured value; a main control module for compensating the measured value and controlling the human body dynamic potential tester as a whole; a power supply module for supplying power to the human body dynamic potential tester; and a housing enclosing the power supply device of the human body dynamic potential tester, the housing being grounded. The present invention is advantageous in eliminating system measurement errors caused by test distance, integrating the signal sampling module within the coaxial high-voltage voltage divider, and thereby reducing environmental noise introduced by signal lines. It is capable of accurately measuring electrostatic dynamic potential and monitoring human body potential in anti-static work areas such as electronic product and pyrotechnic production workshops.

[0068] The serial numbers of the above-mentioned steps involved in the method of the present invention do not mean the order of execution of the method. The execution order of each step should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A human body dynamic potential tester based on capacitance voltage division, characterized in that: include: Potential sensor, using a coaxial capacitive voltage divider, is used to detect potential signals; A signal processing system is provided in the potential sensor and is used to amplify and filter the potential signal to obtain a measurement value; Data visualization module for visualizing measurement values; Main control module, used to compensate the measured values ​​and control the whole body dynamic potential tester; A power module is used to supply power to the human body dynamic potential tester; A housing enclosing the power supply device of the human body dynamic potential tester, wherein the housing is grounded; The potential sensor comprises: The outer metal sleeve is used as the input terminal for measuring the static voltage of the human body; An insulating medium is provided between the inner metal sleeve and the outer metal layer to form a distributed capacitor; A signal sampling module is arranged inside the inner metal sleeve; The signal processing system is equipped with a signal input protection circuit, the surface of which is provided with a protection ring, which is directly connected to the protection buffer via a pressure relief shape connection; The main control module uses a correlation analysis method to screen correlation variables that affect the output, establishes a measurement value compensation model, and compensates the measurement value.

2. The human body dynamic potential tester according to claim 1, characterized in that: The coaxial capacitive voltage divider model was simulated and calculated using the electromagnetic field simulation software ANSYS. The irregularly shaped parts of the model that could not be calculated according to the formula were simulated, the theoretical capacitance values ​​of the high-voltage arm and the low-voltage arm were calculated, and the capacitive voltage divider ratio was obtained.

3. The human body dynamic potential tester according to claim 1, characterized in that: ANSYS software is used to analyze the length of the outer electrode plate, the thickness of the dielectric, the radius of the outer electrode plate, the capacitance value, and the voltage division ratio to obtain the structural data of the potential sensor.

4. The human body dynamic potential tester according to claim 1, characterized in that: The shell comprises a shell surface and a shell frame. The shell surface is subjected to anti-static spraying after chemical conductive oxidation treatment. An elastic conductor pad is provided at the junction of the shell surface and the shell frame.

5. The human body dynamic potential tester according to claim 1, characterized in that: Also includes: Zero calibration circuit, used to zero the input signal and amplifier before measurement.

6. The human body dynamic potential tester according to claim 1, characterized in that: The main control module is a high-performance 32-bit Cortex-M3 core SOC microcontroller STM32F103C8T6 of ARMv7 architecture, with a system clock frequency of 72MHz, a 64K Byte flash memory controller and a 20K Byte SRAM.

7. The human body dynamic potential tester according to claim 1, characterized in that: The data visualization module is a LabVIEW host computer or an LED display screen.

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