CN114034941A - Electric field sensing device for realizing three-dimensional electric field measurement by adopting single-axis motion and realization method - Google Patents

Abstract

The invention provides an electric field sensing device for realizing three-dimensional electric field measurement by adopting single-axis motion and a realization method thereof. The device is designed to be of a field grinding type structure, a rotary rod driven by a motor drives a group of metal spherical shields distributed around the rotary rod to rotate, and periodically shields a horizontal sensing piece group and a vertical sensing piece group, the sensing piece group can generate induced current, an optical signal carrying electric field information is generated through a signal processing circuit, and the optical signal is connected with an upper computer through an optical fiber, so that a three-dimensional electric field around the sensing device can be visually measured on line. The sensing device can parallelly collect electric fields from three directions of a Cartesian three-dimensional coordinate system, and the induced current signals are converted into visual signals to represent the corresponding electric fields through the signal processing circuit, the optical fibers and the upper computer.

Description

Electric field sensing device for realizing three-dimensional electric field measurement by adopting single-axis motion and realization method

Technical Field

The invention belongs to the field of detection technology and automation devices, and particularly relates to an electric field sensing device and an implementation method for realizing three-dimensional electric field measurement by adopting single-axis motion.

Background

With the continuous development of power electronic technology, the high voltage power grid is more and more dense and the surrounding electric field environment is more and more complex, so that a larger electrostatic field and an electric discharge field caused by corona discharge may be generated near the power grid, and the electric fields may interfere with devices in the surrounding environment, such as mobile communication, medical instruments, measuring instruments and the like. Meanwhile, the complex electric field environment around the high-voltage transmission line may have a certain negative influence on the production and life of the masses.

In order to accurately evaluate the influence of the environmental electric field, it is necessary to collect and analyze the influence, and therefore it is increasingly important to measure the electric field strength in the environment more accurately and comprehensively. The traditional electric field measuring device can only measure a one-dimensional electric field in the environment generally, so that the measured electric field intensity has certain dimension defects, and the data is not comprehensive and reliable enough when the electric field intensity in the environment is analyzed. To solve this problem, three-dimensional electric field measuring devices have been developed. Most of the existing three-dimensional electric field measuring devices are realized by arranging and assembling three one-dimensional electric field measuring devices in a special mode or by measuring electric fields with three calibration dimensions by one measuring device in stages. Since the coordination among a plurality of devices is often complex, and the electric field at each moment may be affected by the real-time surrounding environment to change, these measurement methods have the disadvantages of difficult miniaturization, poor reliability of measurement data, and poor on-line measurement capability.

Meanwhile, with the development of the internet of things technology and the communication technology, the sensor is combined with the communication technology, so that the sensor has great development potential, namely, how the sensing device has accurate testing capability in detection and capability of accurately receiving communication signals in communication, and the sensor has important significance for realizing the versatility of a limited system. In order to realize the application of the test sensing device in the communication system, the sensing device is required to have better signal receiving capability, and the sensing device is required to have three-dimensional sensing capability due to the fact that the input direction of the communication signal is various. How to realize the accurate perception of the nondirectional signals in the three-dimensional environment by the sensing device is still a problem to be solved.

In modern production life, the miniaturization of the measuring device is important when analyzing the electric field in some narrow spaces. In some environments where the electric field changes relatively strongly, the online measurement capability is important in order to describe the electric field changes. Meanwhile, the lower electric field measuring device is difficult to accurately sense signals in a three-dimensional environment, so that the assumption of the application of the sensing device in a communication system is difficult to realize. The design of the measuring device requires a comprehensive consideration of the influence of a number of practical factors in order to correctly analyze the electric fields in different complex environments and to make the combined test and communication assumption possible.

Disclosure of Invention

In view of the above mentioned problems, it is aimed to solve the problems in measurement systems while providing a possible sensing means for the concept of combining a measurement system with a communication system. The invention designs the electric field sensing device for realizing three-dimensional electric field measurement by adopting single-axis motion, analyzes the measurement principle, solves the measurement problem of the three-dimensional electric field under the complex electric field environment, and realizes the miniaturization and on-line measurement of the measuring device.

The invention specifically adopts the following technical scheme.

An electric field sensing device for realizing three-dimensional electric field measurement by adopting single-axis motion and a realization method. The electric field sensing device includes: the device comprises a field mill type electric field measuring unit, an optical fiber and an upper computer. The field grinding type electric field measurement unit is used for completing the acquisition and conversion of a space three-dimensional electric field signal; the optical fiber completes the transmission of signals between the field grinding type electric field measuring unit and the upper computer; the upper computer realizes the visual processing of the signals collected by the field mill type electric field measuring unit.

The field mill type electric field measuring unit consists of a three-dimensional electric field sensor, a signal processing unit and a power supply unit; the three-dimensional electric field sensor is composed of a spherical metal shielding body, a rotating rod driven by a motor, a horizontal sensing sheet group and a vertical sensing sheet group. The corresponding electric field intensities in the x, y and z directions are obtained by converting the induced currents on the vertical induction sheet set and the horizontal induction sheet set according to the Gaussian theorem. And synthesizing the electric field strengths in the x, y and z directions on the upper computer according to the vector superposition principle to obtain the total electric field strength to be measured.

The three-dimensional electric field sensor is fixed on the upper part of the field mill type electric field measuring unit. The three-dimensional electric field sensor takes a rotating rod driven by a motor as an axis and is distributed circumferentially. The four spherical metal shields are connected with the top end of a rotating rod driven by a motor and are distributed around the four spherical metal shields in an equidistant and coplanar manner. The horizontal sensing piece group is composed of four horizontal sensing pieces, the four horizontal sensing pieces are equidistantly and coplanarly distributed below the spherical metal shielding body at a certain distance around the rotating rod driven by the motor, and the distance between the circle center of each sensing piece and the central axis of the rotating rod driven by the motor is equal to the distance between the spherical metal shielding body and the central axis of the rotating rod driven by the motor. The vertical induction sheet group is composed of four vertical induction sheets, the circle centers of the four vertical induction sheets are distributed around a rotating rod of the motor transmission at equal intervals, and the circle centers of the four vertical induction sheets are coplanar with the plane formed by the spherical centers of the spherical metal shielding bodies. The metal conductor rods on the horizontal sensing piece group and the vertical sensing piece group penetrate through the metal shielding piece in the middle of the metal shell of the field grinding type measuring unit to be connected with the signal processing unit of the signal processing area below, and the center lines of the metal conductor rods are distributed in an equidistant circle mode relative to the center line of the rotating rod driven by the motor. According to the gauss theorem, the spherical metal shielding body can periodically shield each sensing piece in the horizontal sensing piece group and the vertical sensing piece group when rotating along with the rotating rod driven by the motor, so that corresponding sensing charges can be generated on the sensing pieces. The expression for the induced charge is:

thus, according to the basic current generation formula, the induced current caused by the induced charge can be obtained as:

in the formula

In order to sense the charge induced on the sheet,

to be the electric field strength to be measuredThe degree of the magnetic field is measured,

is the area of the induction sheet exposed in the electric field in the direction to be measured, epsilon is the dielectric constant of the dielectric medium,

is the induced current generated on the induction sheet. Induced current generated in the three-dimensional electric field sensor is sent to the signal processing unit for signal processing, and finally the signal is converted into a corresponding optical signal which is transmitted to an upper computer through an optical fiber for visual reading and operation.

The field mill type electric field measuring unit is arranged in a region to be measured, which needs to measure the electric field intensity, and is used for measuring the electric field intensity of the region to be measured. In order to avoid the influence of an electric field of a region to be measured on a signal processing unit, avoid the mutual influence between a three-dimensional electric field sensor and the signal processing unit and meet the structural requirement of the three-dimensional electric field sensor, the outer shell of the field grinding type electric field measuring unit is designed into a metal cylindrical structure with a metal shielding sheet in the middle, an external electric field is shielded outside the signal processing unit, the three-dimensional electric field sensor and the signal processing unit are shielded and separated by the metal shielding sheet, the region where the three-dimensional electric field sensor is located is called an induction area, and the region where the signal processing unit is located is called a signal processing area. The power supply unit is fixed on the main PCB of the signal processing unit and supplies power for the motor driving the rotating rod driven by the motor to rotate and the active circuit units in other signal processing units. The signal processing unit is mainly used for processing an induced current signal output by the three-dimensional electric field sensor in the sensing device, distinguishing the vector direction of the induced current signal by using a phase-sensitive detection principle, and representing the vector direction and the vector modulus value of the corresponding induced current by using the positive and negative sum amplitude of a direct current signal so as to obtain the vector direction and the vector modulus value of an external electric field corresponding to the external electric field of the induced current.

One terminal of the optical fiber is connected with the signal processing unit through an optical fiber plug on the metal outer shell of the field mill type electric field measuring unit, so that the output of optical signals is realized. And the other terminal of the optical fiber is connected with an upper computer used for experiments, so that the optical signal with the vector direction and the vector modulus of the external electric field output by the signal processing unit is received, and visual reading and operation of the signal by a user are realized.

The invention has the following technical effects:

on one hand, the spherical metal shielding body periodically shields the vertical induction sheet set and the horizontal induction sheet set by rotating around the axis of a rotating rod driven by the motor, so that the device has the characteristics of being capable of respectively and simultaneously sensing the electric field intensity from the x direction, the y direction and the z direction and generating induction current corresponding to the electric field intensity, and the device has reliable three-dimensional electric field measurement capability and strong on-line measurement capability; on the other hand, induced current generated by the vertical sensing piece group and the horizontal sensing piece group is processed by the signal processing unit, the signal is converted into an optical signal, and the optical signal is transmitted to the upper computer through the optical fiber.

The invention can meet the measurement requirement of the three-dimensional electric field and achieve the aim of measuring the three-dimensional electric field intensity on line in real time at high speed, high efficiency, safety and reliability. Meanwhile, the three-dimensional electric field can be measured by adopting single-axis rotation, so that the volume of the electric field sensing device can be miniaturized compared with the traditional electric field sensing device combining a multi-axis rotation principle.

Drawings

FIG. 1 is a schematic diagram of the system architecture of the present invention;

FIG. 2 is a schematic structural diagram of the three-dimensional electric field sensor (2) of the present invention;

FIG. 3 is a schematic view of the structure of the field mill type electric field measuring unit (1) of the present invention;

FIG. 4 is a schematic diagram of the signal processing unit (7) architecture;

fig. 5 is a schematic diagram of the reference level generating circuit (31) architecture.

Wherein, 1-a field mill type electric field measuring unit, 2-a three-dimensional electric field sensor, 3-a metal shielding body, 4-a motor-driven rotating rod, 5-a horizontal sensing piece group, 6-a vertical sensing piece group, 7-a signal processing unit, 8-a power supply unit, 9-an optical fiber, 10-an upper computer, 11-a spherical metal shielding body 1, 12-a spherical metal shielding body 2, 13-a spherical metal shielding body 3, 14-a spherical metal shielding body 4, 15-a vertical sensing piece 1, 16-a vertical sensing piece 2, 17-a vertical sensing piece 3, 18-a vertical sensing piece 4, 19-a horizontal sensing piece 1, 20-a horizontal sensing piece 2, 21-a horizontal sensing piece 3, 22-a horizontal sensing piece 4, 23-a photoelectric coded disc, 24-motor, 25-main PCB, 26-optical fiber plug, 27-I-V conversion circuit, 28-signal amplification circuit, 29-band-pass filter circuit, 30-phase compensation circuit, 31-reference level generation circuit, 32-motor control circuit, 33-phase sensitive detection circuit, 34-low-pass filter circuit, 35-photoelectric conversion circuit, 36-photoelectric switch tube, 37-waveform shaping circuit and 38-frequency divider.

Detailed Description

The technical scheme of the invention is further explained in detail by combining the drawings in the specification.

The invention relates to an electric field sensing device for realizing three-dimensional electric field measurement by adopting single-axis motion and a realization method thereof. As shown in fig. 1, the sensing device is composed of the following parts: the device comprises a spherical metal shielding body (3), a motor-driven rotating rod (4), a horizontal sensing sheet group (5), a vertical sensing sheet group (6), a signal processing unit (7), a power supply unit (8), an optical fiber (9) and an upper computer (10). In the field intensity vector measuring process, the field mill type electric field measuring unit (1) is firstly placed in the electric field area to be measured. Then, three-dimensional electric fields from the x direction, the y direction and the z direction can be radiated to the surfaces of a vertical induction sheet group (6) and a horizontal induction sheet group (5) in the three-dimensional electric field sensor (2), and the spherical metal shielding body (3) rotates around and along with a rotating rod (4) driven by a motor to periodically shield the vertical induction sheet group (6) and the horizontal induction sheet group (5), so that induced currents related to the external electric field intensity to be measured are generated on the surfaces of the vertical induction sheet group (6) and the horizontal induction sheet group (5) (wherein the area of each induction sheet in the horizontal induction sheet group (5) and the vertical induction sheet group (6) is equal to the circular cross-sectional area of the surface of the diameter of each sphere in the spherical metal shielding body (3)). The induced current is then fed to a signal processing unit (7) for processing and generating an optical signal corresponding to the induced current. Finally, the optical signal is transmitted to an upper computer (10) through an optical fiber (9) for visualization processing.

As shown in fig. 1 and 2, the three-dimensional electric field sensor (2) is composed of the following parts: the device comprises a spherical metal shielding body (3), a rotating rod (4) driven by a motor, a horizontal sensing sheet group (5) and a vertical sensing sheet group (6). The spherical metal shield (3) is composed of a spherical metal shield (1), (11), a spherical metal shield (2), (12), a spherical metal shield (3), (13) and a spherical metal shield (14), and is connected and fixed with the top end of a rotating rod (4) driven by a motor through a metal rod. The rotating rod (4) driven by the motor is insulated with a metal shielding sheet used for separating an induction area and a signal processing area in a shell of the field grinding type electric field measuring unit (1) through an insulating sleeve nested by a bearing, and is connected with a motor (24) in the signal processing unit (7) through a shielding body. The horizontal sensing piece group (5) is composed of horizontal sensing pieces 1(19), 2(20), 3(21) and 4(22), and is respectively connected with the signal processing unit (7) by a metal conducting rod penetrating through an insulating sleeve on the metal shielding piece, and the induced current corresponding to the electric field to be measured in the z direction is transmitted to the signal processing unit (7). The vertical sensing piece group (6) is composed of vertical sensing pieces 1(15), 2(16), 3(17) and 4(18), and is respectively connected with the signal processing unit (7) by a metal conducting rod penetrating through an insulating sleeve on the metal shielding piece, and induced currents corresponding to electric fields to be tested in the x and y directions are transmitted to the signal processing unit (7). As shown in formula (2), the induced current can be obtained by gaussian theorem (as shown in formula (1)), because the induced currents in the x and y directions are respectively generated by a differential structure formed by periodically shielding two sets of vertical sensing pieces in the vertical sensing piece group (6) by the spherical metal shielding body (3) (if the vertical sensing pieces 1(15) and the vertical sensing pieces 3(17) are used for calibrating the x direction, the y direction is defined by the vertical sensing pieces 2(16) and the vertical sensing pieces 4(18), and the two sets of sensing pieces can also be used for calibrating x and y interchangeably), the induced currents generated in the x and y directions can be obtained by formula (2) in the forms of formula (3) and formula (4):

in the formula

In order to sense the charge induced on the sheet,

in order to measure the electric field strength,

is the area of the induction sheet exposed in the electric field in the direction to be measured, epsilon is the dielectric constant of the dielectric medium,

in order to induce a current to be generated on the sensing piece,

and

the induced charge on one sensing plate in the x and y directions respectively,

and

the areas of each sensing piece exposed to the electric field in the x and y directions to be measured,

and

the total induced current generated by the group of sensing sheets in the x and y directions, respectively.

Since the induced currents in the z direction are generated by periodically shielding the vertical sensing plates 1(19), 2(20), 3(21) and 4(22) in the vertical sensing plate group (6) by the spherical metal shielding body (3), respectively, the induced currents generated in the z direction can be obtained by the formula (2) in the form of formula (5):

in the formula

The induced charge on one sensing plate in the z direction,

to expose the area of each sensing piece in the z-direction electric field to be measured,

the total induced current generated in the z direction for the group of sense plates.

As shown in fig. 3, the field mill type electric field measuring unit (1) is composed of the following parts: the device comprises a three-dimensional electric field sensor (2), a signal processing unit (7) and a power supply unit (8). The whole metal casing parcel of field mill type electric field measurement unit (1) to the influence and the whole field mill type electric field measurement unit (1) of protection of shielding external electric field to signal processing unit (7), wherein the shell periphery of induction zone has set up 8 outlet in order to prevent that rainy day induction zone ponding from influencing measuring result and casing life. A photoelectric coded disc (23) in the signal processing unit (7) is fixed on a rotating rod (4) driven by a motor and is connected with a photoelectric switch tube (36). The photoelectric switch tube (36) is connected with a waveform shaping circuit (37) in the lower main PCB (25) through a lead. The rotor head of a motor (24) in the signal processing unit (7) is connected with a rotating rod (4) driven by the motor, and the rotating rod (4) driven by the motor is driven to rotate by the rotor head of the motor (24). A motor (24) in the signal processing unit (7) is fixed on the lower main PCB (25), connected with a motor control circuit (32) and controlled by the motor control circuit (32). The optical fiber plug (26) is fixed on a metal shell of the field mill type electric field measuring unit (1), the inner core is connected with a photoelectric conversion circuit (35) in the signal processing unit (7), and an optical signal corresponding to the intensity of the three-dimensional electric field to be measured is transmitted to the upper computer (10) through the optical fiber (9). The power supply unit (8) is fixed on a main PCB (25) of the signal processing unit (7) and provides direct current power for the motor (24) and active devices on other signal processing units (7).

As shown in fig. 4, the signal processing unit (7) is composed of the following parts: the device comprises a motor (24), an I-V conversion circuit (27), a signal amplification circuit (28), a band-pass filter circuit (29), a phase compensation circuit (30), a reference level generation circuit (31), a motor control circuit (32), a phase-sensitive detection circuit (33), a low-pass filter circuit (34) and a photoelectric conversion circuit (35). The induced current generated by the three-dimensional electric field sensor (2) enters an I-V conversion circuit (27) in a signal processing unit (7) to convert a current signal into a voltage signal, the voltage signal is amplified by a signal amplification circuit (28) connected with the I-V conversion circuit (27), interference signals are filtered by a band-pass filter (29) connected with the signal amplification circuit (28) to obtain a useful fundamental frequency signal, the fundamental frequency signal outputs fundamental frequency signals which are respectively the same in frequency as reference levels in the x, y and z directions in a signal reference level generation circuit (31) and have phase differences of 0 degree or 180 degrees through a phase compensation circuit (30) connected with the band-pass filter circuit (29), and the phase differences of the reference signals in the x, y and z directions output by the fundamental frequency signal and the reference level generation circuit (31) determine the x, y and z directions output by a phase detection circuit (33), The positive and negative polarities of the direct current signals in the y-direction signal channel and the z-direction signal channel can determine the magnitude and the direction of induced current signals in the x direction, the y direction and the z direction induced by the three-dimensional electric field sensor (2), and further obtain the magnitude and the direction of an external electric field to be measured in the x direction, the y direction and the z direction. In order to obtain accurate data and conveniently realize visualization processing, a pulse direct current signal containing alternating current signal components generated by a phase-sensitive detection circuit (33) passes through a low-pass filter (34) to obtain a standard direct current signal. As shown in fig. 5, the reference level generating circuit (31) is composed of the following parts: the photoelectric encoder (23), the photoelectric switch tube (36), the waveform shaping circuit (37) and the frequency divider (38). The photoelectric coded disc (23) fixed with the rotating rod (4) driven by the motor in the three-dimensional electric field sensor (2) can generate an optical signal with the same frequency as the induction signal of the horizontal induction sheet group (5), the photoelectric switch tube (36) outputs an electric signal with the same frequency as the optical signal generated by the induction photoelectric coded disc (23) through the optical signal, and the electric signal is shaped into a pulse electric signal with the same frequency as the induction signal of the horizontal induction sheet group (5) through the waveform shaping circuit (37). A part of signals in the reference level generating circuit (31) are directly input into the phase-sensitive detection circuit (33) and have the same frequency with the z-base frequency signal output by the phase compensation circuit (30), and meanwhile, the part of signals can also be input into the motor control circuit (32) as feedback signals to stabilize the rotating speed of the motor. The other part of signals in the reference level generating circuit (31) are converted into two frequency division signals of z-base frequency division signals through a frequency divider (38) (in the vertical sensing piece group (6), the number of sensing pieces in the x-direction sensing piece group and the y-direction sensing piece group is half of that of sensing pieces in the horizontal sensing piece group (5)), so that reference signals in the x-direction and the y-direction are obtained and input into a phase-sensitive detection circuit (33), and the signals are respectively in the same frequency with the x-base frequency division signals and the y-base frequency division signals output by the phase compensation circuit (30). The photoelectric conversion circuit (35) converts the voltage signals in the x, y and z directions output by the low-pass filter (34) and the voltage control signal for controlling the motor control circuit (32) into an optical signal which can be transmitted by the optical fiber (9). The optical signal is received by an upper computer (10) connected with the other terminal of the optical fiber, and the optical signal containing the three-dimensional information of the electric field to be detected and the motor control information is subjected to visual processing by the upper computer (10), so that the data processing and reading are realized.

The applicant of the present invention has described and illustrated the detailed structure and implementation of the present invention in conjunction with the drawings of the specification. It should be understood by those skilled in the art that the above implementation procedures are only preferred implementations of the present invention, and are in the form of descriptions combined with formulas and drawings only for helping the reader to easily understand the design idea of the present invention, and not for limiting the protection scope of the present invention. On the contrary, any improvement or modification made based on the design idea of the present invention should fall within the protection scope of the present invention.

Claims (7)

1. An electric field sensing device and an implementation method for realizing three-dimensional electric field measurement by adopting single-axis motion are characterized in that:

the electric field sensing device comprises a spherical metal shielding body (3), a rotating rod (4) driven by a motor, a horizontal sensing sheet group (5), a vertical sensing sheet group (6), a signal processing unit (7), a power supply unit (8), an optical fiber (9) and an upper computer (10); the four spherical metal shields (3) are equidistantly fixed around the top end of a cylindrical rod of a rotating rod (4) driven by a motor; the horizontal induction sheet group (5) is composed of four metal round sheets which have the same radius as the section of the spherical metal shielding body (3) and are equidistant and are correspondingly and horizontally placed under each spherical metal shielding body for a certain distance, and induction current caused by an electric field in the z direction generated by the horizontal induction sheet group (5) is transmitted into the signal processing unit (7); the vertical induction sheet group (6) is composed of four metal round sheets which have the same radius as the section of the spherical metal shielding body (3) and are equidistant and are correspondingly and vertically placed on each spherical metal shielding body, wherein the direction of each metal round sheet is opposite to that of a rotating rod (4) driven by the motor, and induction currents caused by electric fields in the x direction and the y direction generated by the vertical induction sheet group (6) are transmitted into the signal processing unit (7); the spherical metal shielding body (3), a rotating rod (4) driven by a motor, a horizontal induction sheet group (5) and a vertical induction sheet group (6) form a three-dimensional electric field sensor (2); the signal processing unit (7) and the power supply unit (8) are fixed below a metal shielding sheet at the lower part of the electric field sensor (2), the power supply unit (8) supplies power to the signal processing unit (7) and a motor (24) which drives a rotating rod (4) driven by the motor to rotate, the signal processing unit (7) is used for processing induced currents transmitted by the horizontal sensing sheet group (5) and the vertical sensing sheet group (6) and modulating corresponding optical signals to be transmitted into the optical fiber (9); the signal processing unit (7), the power supply unit (8) and the three-dimensional electric field sensor (2) form a field mill type electric field measuring unit (1); the field mill type electric field measuring unit (1) transmits signals to an upper computer (10) through an optical fiber (9).

2. The three-dimensional electric field sensor (2) according to claim 1, characterized in that:

in order to realize the measurement of the three-dimensional electric field, the three-dimensional electric field sensor (2) fixes four spherical metal shields (3) around the top end of a cylindrical rod of a rotating rod (4) driven by a motor at equal intervals; a rotating rod (4) driven by a motor penetrates through an insulating sleeve and is fixed in a bearing on a metal shielding sheet separating an induction area and a signal processing area; the horizontal induction sheet group (5) and the vertical induction sheet group (6) penetrate through the insulating sleeve and are fixed on the separation metal shielding sheets of the induction area and the signal processing area, the horizontal induction sheet group (5) is distributed at the lower sides of the four spherical metal shielding bodies (3) and has the same height, the electric field intensity to be measured in the z direction is measured, the vertical induction sheet group (6) is distributed at the outer sides of the four spherical metal shielding bodies (3) and has the same height, and the opposite induction sheet groups are arranged to measure the electric field intensity to be measured in the x direction and the y direction respectively. The structural dimension parameters of the three-dimensional electric field sensor (2) need to be designed according to actual measurement requirements and actual measurement environments.

3. The field milling type electric field measuring unit (1) according to claim 1, characterized in that:

the field mill type electric field measuring unit (1) is used for meeting the requirements of the structure of the three-dimensional electric field sensor (2), shielding the influence of an external electric field on a signal processing circuit and realizing miniaturization. A cylindrical shell is designed, a metal shielding sheet is horizontally fixed in the middle of the shell, a field mill type electric field measuring unit (1) is divided into an induction area and a signal processing area, a three-dimensional electric field sensor (2) is located in the induction area, and a signal processing unit (7) and a power supply unit (8) are located in the signal processing area; the shell is completely made of metal materials, and the structural size parameters of the shell are designed according to the measurement requirements and the specific size of the three-dimensional electric field sensor (2).

4. The signal processing unit (7) according to claim 1, characterized in that:

the signal processing unit (7) comprises an I-V conversion circuit (27), a signal amplification circuit (28), a band-pass filter circuit (29), a phase compensation circuit (30), a reference level generation circuit (31), a phase sensitive detection circuit (33), a low-pass filter circuit (34), a photoelectric conversion circuit (35), a motor (24) and a motor control circuit (32). In order to meet the structural requirement of the cylindrical shell of the field grinding type electric field measuring unit (1), the PCB of the signal processing unit is designed to be circular, and the structural size is designed according to the specific size of the cylindrical shell of the field grinding type electric field measuring unit (1).

5. Optical fiber (9) according to claim 1, characterized in that:

the optical fiber (9) embeds the transmission medium in the insulator, is used for parallelly transmitting three paths of optical signals which respectively carry the electric field information in the x direction, the y direction and the z direction and optical signals for motor control, and ensures that the signals are transmitted at high speed, efficiently and safely.

6. The three-dimensional electric field sensor (2) according to claim 2, characterized in that:

the principle that the horizontal induction sheet group (5) measures the electric field in the z direction and the vertical induction sheet group (6) measures the electric fields in the x and y directions is as follows: the spherical metal shielding body (3) periodically shields the horizontal induction sheet set (5) and the vertical induction sheet set (6) and generates induction current on the induction sheet sets, so that the three-dimensional electric field sensing method suitable for the device can be formed based on Gaussian theorem. The calibration of the electric fields in the x direction and the y direction is calibrated by setting the normal direction of one group of induction sheets in the opposite direction in the vertical induction sheet group (6) as the x direction and setting the normal direction of the other group of induction sheets with a 90-degree difference with the normal direction as the y direction; the calibration of the electric field in the z direction is calibrated through the normal direction of the horizontal induction sheet group (5).

7. The three-dimensional electric field sensing method according to claim 6, characterized in that:

the three-dimensional electric field sensing method is a three-dimensional electric field conversion method based on Gaussian theorem and combined with the device structure of claim 1, and is used for solving induced currents generated on the horizontal induction sheet group (5) and the vertical induction sheet group (6). The induced currents in the x and y directions are calculated firstly, and because two induction sheets in two groups of induction sheets in the vertical induction sheet group (6) are oppositely arranged, the induced currents obtained in the x and y directions are in a differential form, and the magnitude of the induced currents is twice that of the current on one induction sheet in each group. And then calculating the induced current in the z direction, wherein the induced current obtained in the z direction is four times of the current on one induction sheet because the four induction sheets in the horizontal induction sheet group (5) are horizontally arranged in the same direction. And finally, determining the electric field in the corresponding direction according to the induced currents in the x, y and z directions, and obtaining the total electric field through vector synthesis. Wherein the induced currents are solved in conjunction with the gaussian theorem. The gaussian theorem can be described as:

in the formula

In order to sense the charge induced on the sheet,

in order to measure the electric field strength,

epsilon is the area of the induction sheet exposed to the electric field in the direction to be measured, and epsilon is the dielectric constant of the dielectric medium. To pair

The derivation can obtain the induced current on each sensing piece as:

in the formula

Is the induced current generated on the induction sheet.

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