JP6364584B2 - Atmospheric electric field detector - Google Patents

Description

  The present invention relates to an apparatus for measuring a change in electric field intensity on the ground during a thundercloud growth process.

  Lightning strike refers to a phenomenon in which a complete discharge occurs between a thundercloud and the ground through a process in which a precursor discharge (step leader) is repeatedly emitted from the thundercloud bottom to the ground and the insulation of the atmosphere is destroyed. In order to predict the occurrence of a lightning strike, it is important to grasp spatiotemporal information about the behavior of the atmospheric electric field between a thundercloud and the ground. If the state of the atmospheric electric field can be detected with high reliability, an accurate lightning forecast will be possible. That is, the temporal and spatial changes in the ground electric field are measured, and if there is an electric field change that can be estimated that the atmosphere will eventually lead to discharge destruction, it may be determined that there is a risk of lightning strike.

  Conventionally, a rotating electrode type electrometer is usually used for measuring a DC ground electric field. The rotating electrode type electrometer collects and measures the amount of electric charge corresponding to the atmospheric electric field with a fixed electrode by an opening / closing operation by a rotating ground shielding plate, that is, a rotating electrode. For example, in Non-Patent Document 1, when terrestrial electric field measurement is performed with a rotating electrode type electrometer, the calibration method of the electrometer is examined, and the basic terrestrial electric field waveform during a lightning strike for winter lightning is theoretically examined. Are summarized. The principle of the rotating electrode type electrometer is also applied as a high-voltage DC electric field measuring device (for example, see Non-Patent Document 2).

Aihara et al., “Estimation of measurement error and electric field waveform during winter lightning ground electric field measurement”, Central Research Institute of Electric Power Industry, Central Research Institute of Electric Power Industry, Research report: T94069, June 1995 Tant, P., Bolsens, B., Sels, T., Van Dommelen, D., Driesen, J., Belmans, R., “Design and Application of a Field Mill as a High-Voltage DC Meter”, IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, VOL.56, NO.4, AUGUST 2007

  However, the rotating electrode type electrometer described above requires an electric drive mechanism for rotating the ground shielding plate at a constant speed. That is, in addition to a circuit for performing electric field measurement, a circuit device for rotating the rotating electrode at a constant speed is required, and thus the device has become large. Also, in the severe cold season, the shielding plate does not rotate due to icing, making measurement impossible, or small insects enter the drive mechanism, causing a large error in the collected charge amount, etc. There are many problems in continuous measurement.

  In view of the above-described problems, the present invention realizes an atmospheric electric field detection device that is highly reliable and capable of stable operation with an extremely simple configuration that does not have a rotation mechanism.

  In one aspect of the present invention, an atmospheric electric field detection device includes a receiving antenna having opposed first and second electrodes, a reference electrode provided between the first and second electrodes, and the first and second electrodes. An electronic circuit unit for detecting a voltage generated between the electrodes, a first signal line connecting the first electrode and the electronic circuit unit, and a second signal connecting the second electrode and the electronic circuit unit And a signal line portion having a reference potential line connecting the reference electrode and the electronic circuit portion, and the electronic circuit portion generates a voltage between the first signal line and the reference potential line. A first integrating circuit for integrating; a second integrating circuit for integrating the voltage between the second signal line and the reference potential line; and receiving the outputs of the first and second integrating circuits as differential inputs for amplification And a differential amplifier.

  According to this aspect, the receiving antenna has a three-pole structure. Voltage signals generated between the first electrode and the reference electrode and between the second electrode and the reference electrode of the receiving antenna by the atmospheric electric field are balanced and transmitted to the electronic circuit unit via the signal line unit, respectively. In the electronic circuit unit, the voltage signal between the first electrode and the reference electrode is integrated by the first integration circuit, the voltage signal between the second electrode and the reference electrode is integrated by the second integration circuit, and the first and second integration circuits Is amplified as a differential signal by a differential amplifier. As a result, the atmospheric electric field can be accurately measured with a very simple configuration without requiring a rotating mechanism.

  In addition, since a common reference potential is maintained and secured between the three-pole receiving antenna and the electronic circuit section via the reference potential line, grounding is always required when installing the atmospheric electric field detection device. There is no need. For this reason, it can be set as a portable atmospheric electric field detection apparatus easily.

  The first and second electrodes and the reference electrode may be configured by flat plates provided in parallel to each other.

  Furthermore, the receiving antenna is connected to the reference electrode, and is configured to surround the first and second electrodes in the circumferential direction when the normal direction of the flat plate is an axial direction. It is good also as providing the shield part.

  Further, the first and second electrodes and the reference electrode may be hemispherical.

  The electronic circuit unit includes a first filter circuit having a CR configuration connected to the output line of the first integration circuit, and a second filter circuit having a CR configuration connected to the output line of the second integration circuit. And a filter for limiting the reception band may be provided.

  Thereby, the frequency band which performs atmospheric electric field detection can be set up easily.

The signal line portion may include a shielded cable having a shield conductor covering the first and second signal lines, and the shield conductor may constitute a part of the reference potential line. In addition, resistance to common mode noise such as a power supply frequency when a voltage signal from the receiving antenna is transmitted to the electronic circuit unit can be enhanced.

  Further, the differential amplifier may be added with a gain adjustment resistor.

  As a result, the output voltage level of the differential amplifier can be adjusted by the gain adjustment resistor, so that gain adjustment according to the frequency band in which the atmospheric electric field detection is performed becomes possible.

  In another aspect of the present invention, an atmospheric electric field detection device includes a receiving antenna having first and second electrodes facing each other, an electronic circuit unit for detecting a voltage generated between the first and second electrodes, A first signal line connecting the first electrode and the electronic circuit unit; and a signal line unit having a second signal line connecting the second electrode and the electronic circuit unit; Includes a first integrating circuit that integrates a voltage between the first signal line and the ground line, a second integrating circuit that integrates a voltage between the second signal line and the ground line, and the first And a differential amplifier for receiving and amplifying the output of the second integrating circuit as a differential input.

  According to this aspect, the voltage signal generated between the first and second electrodes of the receiving antenna by the atmospheric electric field is balanced and transmitted to the electronic circuit unit via the signal line unit. In the electronic circuit unit, the voltage signal between the first electrode and the ground is integrated by the first integration circuit, the voltage signal between the second electrode and the ground is integrated by the second integration circuit, and the outputs of the first and second integration circuits Is amplified as a differential signal by a differential amplifier. As a result, the atmospheric electric field can be accurately measured with a very simple configuration without requiring a rotating mechanism.

  In another aspect of the present invention, an atmospheric electric field detection device includes a receiving antenna having first and second electrodes facing each other, an electronic circuit unit for detecting a voltage generated between the first and second electrodes, A first signal line connecting the first electrode and the electronic circuit unit; and a signal line unit having a second signal line connecting the second electrode and the electronic circuit unit; Is a DC / AC conversion circuit that converts a DC signal component in a signal that is balanced and transmitted via the signal line unit into an AC signal component of a predetermined frequency, and an output signal of the DC / AC conversion circuit, A band-pass filter configured to pass a component of a predetermined band including the predetermined frequency; and a differential amplifier that receives and amplifies the output of the band-pass filter as a differential input. The DC / AC conversion circuit has first and second input terminals and first and second output terminals, and the first and second input terminals are connected to the first and second signal lines, respectively. And integrating a voltage between the first output terminal of the four-terminal variable capacitor and the ground line so that the capacitance value between the first and second output terminals can be varied. And a second integrating circuit for integrating a voltage between the second output terminal of the four-terminal variable capacitor and the ground line, and the first and second of the four-terminal variable capacitor. The capacitance value between the output terminals is varied with the predetermined frequency.

  According to this aspect, the voltage generated between the first and second electrodes of the receiving antenna by the atmospheric electric field is balanced and transmitted to the electronic circuit unit via the signal line unit. Among these voltages, the voltage due to the DC atmospheric electric field is converted into an AC signal component of a predetermined frequency by a DC / AC conversion circuit having a four-terminal variable capacitor capable of changing the capacitance value, and unnecessary noise is generated by a bandpass filter. After being removed, it is amplified by a differential amplifier. As a result, the DC atmospheric electric field can be accurately measured with a very simple configuration without requiring a rotating mechanism. In addition, by using a four-terminal variable capacitor, the polarity of the electric field can be determined together with the detection of the DC electric field.

  The four-terminal variable capacitor includes a vibrating electrode connected to the first output terminal and a fixed electrode connected to the second output terminal, and the first and second variable capacitors are vibrated by vibrating the vibrating electrode. The capacitance value between the second output terminals may be configured to be variable.

  According to the present invention, it is possible to realize an atmospheric electric field detection device that is highly reliable and capable of stable operation with an extremely simple configuration that does not have a rotation mechanism.

Basic configuration diagram of an atmospheric electric field detection device according to the first embodiment The figure which shows the circuit structural example of the atmospheric electric field detection apparatus which concerns on 1st Embodiment. Alternative components of integration circuit It is a figure which shows an example of a structure of a receiving antenna, (a) is a top view, (b) is sectional drawing. It is a figure which shows an example of a structure of a receiving antenna, (a) is a top view, (b) is sectional drawing. Graph showing an example of experimental results Configuration example of electronic circuit unit with filter Sectional drawing which shows the example of another structure of a receiving antenna The figure which shows the circuit structural example of the atmospheric electric field detection apparatus which concerns on 2nd Embodiment. Basic configuration diagram of an atmospheric electric field detection device according to a third embodiment The figure which shows the circuit structural example of the atmospheric electric field detection apparatus which concerns on 3rd Embodiment. (A)-(d) is a structural example of the 4-terminal variable capacitor used for the circuit structure of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing a basic configuration of an atmospheric electric field detection device according to the first embodiment of the present invention. In FIG. 1, a receiving antenna 1 converts an atmospheric electric field Ea into a voltage and has a three-pole structure. That is, the receiving antenna 1 includes the first electrode 11 and the second electrode 12 that face each other, and the reference electrode 13 that is provided between the first electrode 11 and the second electrode 12. The receiving antenna 1 is installed so as to be substantially horizontal. That is, the receiving antenna 1 is arranged so that the electrode surface is orthogonal to the direction of the lightning electric field generated between the thundercloud and the ground, in other words, the normal direction of the electrode surface is substantially vertical.

  The electronic circuit unit 5 detects a voltage generated between the first and second electrodes 11 and 12 and outputs an output signal indicating the detected voltage. The signal line unit 20 includes a shielded cable 23 having a shield conductor 24 covering the first and second signal lines 21 and 22, and the first signal line 21 connects the first electrode 11 and the electronic circuit unit 5. The second signal line 22 connects the second electrode 12 and the electronic circuit unit 5. The shield conductor 24 of the shield cable 23 is connected to the reference electrode 13 and is also connected to the electronic circuit unit 5. That is, the shield conductor 24 constitutes a part of the reference potential line 25 that connects the reference electrode 13 and the electronic circuit unit 5. The signal line unit 20 transmits the signal voltage in a balanced manner and secures a reference potential of the signal to be transmitted.

  The electronic circuit unit 5 integrates a voltage between the first signal line 21 and the reference potential line 25 and a first integration circuit 31 that integrates a voltage between the second signal line 22 and the reference potential line 25. And a differential amplifier 40 for receiving and amplifying the outputs of the first and second integration circuits 31 and 32 as differential inputs. The output of the differential amplifier 40 becomes the output signal of the electronic circuit unit 5. From this output signal, a practical signal can be acquired, for example, by signal processing or the like, and can be utilized for, for example, lightning prediction.

FIG. 2 is a circuit configuration example of the atmospheric electric field detection device according to the present embodiment. 2, the receiving antenna 1 is represented by the capacitance C _0. The shielded cable 23 is represented by a capacitance C _c between the first and second signal lines 21 and 22 and the reference potential line 25. In FIG. 2, the shield conductor 24 of the shield cable 23 is grounded in common with the reference electrode 13, the common potential terminal of the first and second integrating circuits 31 and 32, and the reference voltage terminal ref of the differential amplifier 40 described later. Has been. Thereby, noise resistance when the voltage signal of the receiving antenna 1 is transmitted to the electronic circuit unit 5 is enhanced.

The first and second integrating circuits 31 and 32 have the same circuit configuration. The first integration circuit 31 includes an operational amplifier 31a. Operational amplifier 31a is an inverting input is connected via a first signal line 21 resistance R _s, the non-inverting input is connected via a resistor R _b reference potential line 25. Furthermore, between the output and the inverting input, resistor R _d and the capacitance C _s are connected in parallel. The second integration circuit 32 includes an operational amplifier 32a. Operational amplifier 32a is an inverting input is connected via a and a resistor R _s second signal line 22, the non-inverting input is connected via the reference potential line 25 to resistor R _b. Furthermore, between the output and the inverting input, resistor R _d and the capacitance C _s are connected in parallel.

The resistor _Rd has a role of time constant adjustment and discharge function. For example, when a DC offset voltage is generated by increasing the time constant, the configuration of the part X in the first and second integration circuits 31 and 32 may be a T-type network configuration as shown in FIG.

The differential amplifier 40 includes an operational amplifier 41. The operational amplifier 41 receives the output of the first integrating circuit 31 as an inverting input and receives the output of the second integrating circuit 32 as a non-inverting input. That is, the differential amplifier 40 receives and amplifies the outputs of the first and second integrating circuits 31 and 32 as differential inputs. The reference voltage terminal ref of the differential amplifier 40 is connected to the reference potential line 25 and grounded. The operational amplifier 41 is added with a gain setting resistor _RG for adjusting the gain.

  With such a configuration, the voltage generated between the first electrode 11 and the reference electrode 13 and between the second electrode 12 and the reference electrode 13 of the receiving antenna 1 by the atmospheric electric field Ea passes through the signal line unit 20, respectively. Thus, balanced transmission is performed to the electronic circuit unit 5. In the electronic circuit unit 5, the voltage signal between the first electrode 11 and the reference electrode 13 is integrated by the first integrating circuit 31, the voltage signal between the second electrode 12 and the reference electrode 13 is integrated by the second integrating circuit 32, The outputs of the first and second integrating circuits 31 and 32 are amplified by the differential amplifier 40 as differential signals. Thereby, an atmospheric electric field can be measured with high accuracy by an extremely simple configuration without requiring a rotating part.

  4A and 4B show examples of the electrode shape of the receiving antenna 1. FIG. 4A is a plan view and FIG. 4B is a cross-sectional view. In the example of FIG. 4, the first and second electrodes 11, 12 and the reference electrode 13 are respectively configured by flat plates provided in parallel to each other, and are supported by the support portion 14 in an insulated state. The planar shapes of the first and second electrodes 11 and 12 are circular, the same shape, and the same area. The planar shape of the reference electrode 13 is also circular, is concentric with the first and second electrodes 11 and 12 in plan view, and has a larger diameter than the first and second electrodes 11 and 12.

  FIG. 5 shows another example of the electrode shape of the receiving antenna 1, wherein (a) is a plan view and (b) is a cross-sectional view. In the example of FIG. 5, as in the example of FIG. 4, the first and second electrodes 11, 12 and the reference electrode 13 are respectively configured by flat plates provided in parallel to each other, and are insulated from each other by the support portion 14. It is supported by. The planar shapes of the first and second electrodes 11 and 12 are circular, the same shape, and the same area. The planar shape of the reference electrode 13 is also circular, is concentric with the first and second electrodes 11 and 12 in plan view, and has a larger diameter than the first and second electrodes 11 and 12.

  The receiving antenna 1 of FIG. 5 further includes a shield portion 15 connected to the reference electrode 13. The shield portion 15 surrounds the first and second electrodes 11 and 12 in the circumferential direction when the normal direction of the flat plates constituting the first and second electrodes 11 and 12 and the reference electrode 13 is the axial direction. It is configured.

  The receiving antenna 1 of FIG. 4 can receive an electric field oblique to the vertical direction. For this reason, it is possible to detect an electric field in the vicinity of a thundercloud (for example, more than 10 km), which is effective for lightning prediction at a medium distance. On the other hand, the receiving antenna 1 of FIG. 5 can receive only the electric field in the vertical direction. For this reason, it is possible to detect an electric field directly under a thundercloud (for example, within 10 km), which is effective for lightning strike prediction in a short distance.

  Various other electrode shapes for the receiving antenna are conceivable. For example, it may be a square shape or a polygonal shape such as a hexagon. Alternatively, a shape in which a plurality of electrode pieces are electrically connected may be used. Moreover, although it is preferable that the 1st electrode 11 and the 2nd electrode 12 are mutually the same shape and are equal areas, it is not necessarily restricted to this. Further, the reference electrode 13 may have a shape different from that of the first and second electrodes 11 and 12.

  FIG. 6 is an example of data obtained as a result of experiments by the inventors. In FIG. 6, the horizontal axis represents the intensity of the electric field applied on a trial basis, and the vertical axis represents the output of the atmospheric electric field detection device according to the present embodiment. In the thundercloud electric field leading to a lightning strike, an electric field fluctuation including a slow electric field fluctuation and an instantaneous high-frequency component occurs. From FIG. 6, a linear output with respect to the electric field strength is obtained regardless of the frequency of the electric field fluctuation. I understand that.

As described above, according to the present embodiment, the atmospheric electric field detection capable of high reliability and stable operation with an extremely simple configuration without the need for a rotation mechanism as in the conventional rotating electrode type electrometer. An apparatus can be realized. That is, voltage signals generated between the first electrode 11 and the reference electrode 13 and between the second electrode 12 and the reference electrode 13 of the receiving antenna 1 by the atmospheric electric field Ea are respectively transmitted to the signal line unit 20. Via the balanced transmission to the electronic circuit unit 5. In the electronic circuit unit 5, the voltage signal between the first electrode 11 and the reference electrode 13 is integrated by the first integrating circuit 31, the voltage signal between the second electrode 12 and the reference electrode 13 is integrated by the second integrating circuit 32, The outputs of the first and second integrating circuits 31 and 32 are amplified by the differential amplifier 40 as differential signals. As a result, the atmospheric electric field can be accurately measured with a very simple configuration without requiring a rotating mechanism. In addition, since a common reference potential is maintained and secured between the reception antenna 1 having the three-pole structure and the electronic circuit unit 5 via the reference potential line 25, grounding is performed when the atmospheric electric field detection device is installed. There is no need to take For this reason, it can be set as a portable atmospheric electric field detection apparatus easily. Further, since the output voltage level of the differential amplifier 40 can be adjusted by the gain adjustment resistor _RG , gain adjustment according to the frequency band in which the atmospheric electric field detection is performed becomes possible.

(Modification)
As shown in FIG. 7, a filter 50 for limiting the reception band may be provided between the first and second integrating circuits 31 and 32 and the differential amplifier 40. The filter 50 includes a first filter circuit 51 having a CR configuration connected to the output line of the first integration circuit 31, and a second filter circuit 52 having a CR configuration connected to the output line of the second integration circuit 32. Yes. Here, the CR configuration refers to a configuration including a capacitive element (C) and a resistance element (R). In Figure 7, the first filter circuit 51 has a configuration in which a capacitor C ₁ and a resistor R ₁ connected in series, and other resistive elements R ₁ are connected in parallel. The second filter circuit 52 has the same configuration as the first filter circuit 31.

By appropriately setting the capacitance value of the capacitive element C ₁ and the resistance value of the resistive element R ₁ , the time constants of the first and second filter circuits 51 and 52 can be set to desired values. For example, the filter can be configured so that the time constant can be adjusted by using a variable capacitance element or a variable resistance element. Alternatively, the filter can be configured such that the time constant can be set by replacing the capacitor element and the resistor element. That is, since the frequency characteristics of the first and second filter circuits 51 and 52 can be set or adjusted, the frequency band for performing atmospheric electric field detection can be easily set. The configuration of the filter circuit is not limited to that shown here.

  In the above-described embodiment, each of the electrodes 11, 12, and 13 of the receiving antenna 1 is configured by flat plates provided in parallel to each other. However, the present invention is not limited to this. For example, FIG. 8 is a cross-sectional view showing another configuration example of the electrode of the receiving antenna. In the configuration of FIG. 8, the receiving antenna 1A is formed in a hemispherical shape. In other words, each of the first electrode 11A, the second electrode 12A, and the reference electrode 13A has a hemispherical shape and is supported by the support portion 14 in an insulated state. The receiving antenna 1A of FIG. 8 can receive electric fields from almost all directions. For this reason, it is possible to detect an electric field around a thundercloud (for example, more than 10 km), which is useful for installation in a building group space, for example.

(Second Embodiment)
In the first embodiment, the receiving antenna 1 has a three-pole structure. However, the circuit configuration described above can also be applied to a two-pole receiving antenna.

  FIG. 9 is a diagram showing a circuit configuration example of the atmospheric electric field detection device according to the second embodiment of the present invention. In FIG. 9, the receiving antenna 2 converts the atmospheric electric field Ea into a voltage, and has a bipolar structure. That is, the receiving antenna 2 has a first electrode 11 and a second electrode 12 that face each other. The circuit configuration of the electronic circuit unit 5 is the same as that shown in FIG. That is, in the electronic circuit unit 5, the first integration circuit 31 integrates the voltage between the first signal line 21 and the ground line. The second integration circuit 32 integrates the voltage between the second signal line 22 and the ground line. The differential amplifier 40 receives and amplifies the outputs of the first and second integrating circuits 31 and 32 as differential inputs. A CR configuration first filter circuit 51 is connected to the output line of the first integration circuit 31, and a CR configuration second filter circuit 52 is connected to the output line of the second integration circuit 32. Note that the first and second filter circuits 51 and 52 may be omitted as in the first embodiment.

  According to the present embodiment, voltage signals generated between the first and second electrodes 11 and 12 of the receiving antenna 2 by the atmospheric electric field Ea are balanced and transmitted to the electronic circuit unit 5 via the signal line unit 20, respectively. . In the electronic circuit unit 5, the voltage signal between the first electrode 11 and the ground is integrated by the first integrating circuit 31, the voltage signal between the second electrode 12 and the ground is integrated by the second integrating circuit 32, and the first and first The outputs of the two integrating circuits 31 and 32 are amplified by the differential amplifier 40 as a differential signal. As a result, the atmospheric electric field can be accurately measured with a very simple configuration without requiring a rotating mechanism.

(Third embodiment)
FIG. 10 is a diagram showing a basic configuration of an atmospheric electric field detection device according to the third embodiment of the present invention. The configuration of FIG. 10 enables detection of a direct-current atmospheric electric field (DC-AEF), and a DC / AC conversion circuit 60 is cascade-connected in front of the electronic circuit unit 5A. 10, components common to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and detailed description thereof is omitted here.

  The electronic circuit unit 5A includes a DC / AC conversion circuit 60 that converts a DC signal component in a signal that is balanced and transmitted via the signal line unit 20 into an AC signal component having a predetermined frequency, and an output of the DC / AC conversion circuit 60. A band filter 70 that performs frequency discrimination on a signal and a differential amplifier 40 that receives and amplifies the output of the band filter 70 as a differential input are provided. The band filter 70 is configured to allow a component of a predetermined band including a predetermined frequency converted by the DC / AC conversion circuit 60 to pass therethrough. As in the first embodiment, the output of the differential amplifier 40 becomes the output signal of the electronic circuit unit 5A. From this output signal, a practical signal can be acquired, for example, by signal processing or the like, and can be utilized for, for example, lightning prediction.

  FIG. 11 is a circuit configuration example of the atmospheric electric field detection device according to the present embodiment. In FIG. 11, the same components as those in FIG. 2 are denoted by the same reference numerals as those in FIG. 2, and detailed description thereof is omitted here. The DC / AC conversion circuit 60 is a four-terminal variable capacitor 63 that is a four-terminal capacitor having buffer amplifiers 61 and 62 for suppressing attenuation of received charges, and input terminals N1 and N2 and output terminals N3 and N4. And first and second integration circuits 64 and 65. The 4-terminal variable capacitor 63 is configured to be able to vary the capacitance value Cv between the output terminals N3 and N4. The first integration circuit 64 integrates the voltage between the output terminal N3 of the four-terminal variable capacitor 63 and the ground line. The second integration circuit 65 integrates the voltage between the output terminal N4 of the four-terminal variable capacitor 63 and the ground line. The bandpass filter 70 includes a first bandpass filter (BPF) 71 provided on the output line side of the first integration circuit 64 and a second bandpass filter (BPF) provided on the output line side of the second integration circuit 65. 72. The first and second BPFs 71 and 72 may have a CR configuration using, for example, a variable capacitance element and a variable resistance element.

  FIG. 12 shows an example of the configuration of the four-terminal variable capacitor 63. 12A to 12C, the four-terminal variable capacitor 63 includes a vibrating electrode connected to the output terminal N3 and an output terminal N4 between the electrodes to which the input terminals N1 and N2 are connected. And a fixed electrode connected to. In the example of FIG. 12A, the vibrating electrode is configured to vibrate up and down without contacting the fixed electrode. In the example of FIG. 12B, the vibration electrode is vibrated obliquely without contacting the fixed electrode. In the example of FIG. 12C, the vibration electrode is vibrated up and down without being brought into contact with the fixed electrode by controlling the piezoelectric element. In either case, the capacitance value between the output terminals N3 and N4 can be varied by vibrating the vibrating electrode. In the example of FIG. 12D, the four-terminal variable capacitor 63 is provided with fixed electrodes connected to the output terminals N3 and N4 between the electrodes connected to the input terminals N1 and N2, respectively. In addition, a dielectric plate is provided between the fixed electrodes. The dielectric plate is configured to be able to vibrate in a direction parallel to the fixed electrode without contacting the fixed electrode.

  Specifically, the first and second integration circuits 64 and 65 may be configured similarly to the first and second integration circuits 31 and 32 shown in the first embodiment, for example. The first and second integration circuits 64 and 65 have spike noise absorption and reception charge maintenance for the output of the four-terminal variable capacitor 63, and a DC offset voltage suppression function.

  The DC-AC conversion circuit 60 converts the DC charge generated by the DC-AEF reception into an AC voltage (AC signal) that changes at a predetermined frequency via the four-terminal variable capacitor 63. The band filter 70 removes unnecessary noise and allows only the AC signal to pass through due to band limitation. A DC atmospheric electric field can be detected from the output of the differential amplifier 40 in this case. That is, according to the present embodiment, an electric field that does not change or an electric field that changes very slowly can be detected with a very simple configuration without requiring a rotating mechanism. Moreover, since other frequency components can also be observed by the frequency discrimination by the band filter 70, the AC atmospheric electric field (AC-AEF) and the pulsed atmospheric electric field (PULSE-AEF) should be detected together with the DC atmospheric electric field. Can do. Further, by using the four-terminal variable capacitor 63, the polarity of the electric field can be determined together with the detection of the DC electric field.

  In this embodiment, the receiving antenna 1 has a three-pole structure. However, the circuit configuration described above can also be applied to a two-pole receiving antenna. In this case, it is only necessary to omit the connection between the reference electrode 13 of the receiving antenna 1 and the shielding conductor 24.

  In the present invention, an atmospheric electric field detection device capable of stable operation with high reliability can be realized with an extremely simple configuration. For example, lightning can be detected by a lightning observation method in which the device according to the present invention is arranged at three or more fixed points in a wide range. The prediction accuracy can be improved.

1, 1A, 2 Receiving antenna 5, 5A Electronic circuit part 11, 11A First electrode 12, 12A Second electrode 13, 13A Reference electrode 15 Shield part 20 Signal line part 21 First signal line 22 Second signal line 23 Shielded cable 24 shield conductor 25 reference potential line 31 first integration circuit 32 second integration circuit 40 differential amplifier 50 filter 51 first filter circuit 52 second filter circuit 60 DC / AC conversion circuit 63 four-terminal variable capacitor 64 first integration circuit 65 Second integration circuit 70 Bandpass filter Ea Atmospheric electric field _RG Gain adjustment resistor N1, N2 Input terminal N3, N4 Output terminal

Claims (10)

A receiving antenna having first and second electrodes facing each other and a reference electrode provided between the first and second electrodes;
An electronic circuit unit for detecting a voltage generated between the first and second electrodes;
A first signal line connecting the first electrode and the electronic circuit unit; a second signal line connecting the second electrode and the electronic circuit unit; and connecting the reference electrode and the electronic circuit unit. A signal line portion having a reference potential line,
The electronic circuit unit is
A first integration circuit for integrating a voltage between the first signal line and the reference potential line;
A second integrating circuit for integrating a voltage between the second signal line and the reference potential line;
An atmospheric electric field detection device comprising: a differential amplifier for receiving and amplifying outputs of the first and second integration circuits as differential inputs. In the atmospheric electric field detection device according to claim 1,
The atmospheric electric field detection device, wherein the first and second electrodes and the reference electrode are configured by flat plates provided in parallel to each other. The atmospheric electric field detection device according to claim 2,
The receiving antenna is
A shield portion connected to the reference electrode and configured to surround the first and second electrodes in the circumferential direction when the normal direction of the flat plate is an axial direction; An atmospheric electric field detector. In the atmospheric electric field detection device according to claim 1,
The atmospheric electric field detection device, wherein the first and second electrodes and the reference electrode are formed in a hemispherical shape. In the atmospheric electric field detection device according to any one of claims 1 to 4,
The electronic circuit unit is
A first filter circuit having a CR configuration connected to the output line of the first integration circuit; and a second filter circuit having a CR configuration connected to the output line of the second integration circuit, and limiting a reception band. An atmospheric electric field detection device comprising a filter for the purpose. In the atmospheric electric field detection device according to any one of claims 1 to 5,
The signal line portion includes a shielded cable having a shield conductor covering the first and second signal lines,
The atmospheric electric field detection device, wherein the shielding conductor constitutes a part of the reference potential line. In the atmospheric electric field detection device according to any one of claims 1 to 6,
The atmospheric amplifier according to claim 1, wherein a gain adjusting resistor is added to the differential amplifier. A receiving antenna having opposing first and second electrodes;
An electronic circuit unit for detecting a voltage generated between the first and second electrodes;
A first signal line connecting the first electrode and the electronic circuit unit, and a signal line unit having a second signal line connecting the second electrode and the electronic circuit unit,
The electronic circuit unit is
A first integrating circuit for integrating a voltage between the first signal line and the ground line;
A second integrating circuit for integrating a voltage between the second signal line and the ground line;
An atmospheric electric field detection device comprising: a differential amplifier for receiving and amplifying outputs of the first and second integration circuits as differential inputs. A receiving antenna having opposing first and second electrodes;
An electronic circuit unit for detecting a voltage generated between the first and second electrodes;
A first signal line connecting the first electrode and the electronic circuit unit, and a signal line unit having a second signal line connecting the second electrode and the electronic circuit unit,
The electronic circuit unit is
A DC / AC conversion circuit for converting a DC signal component in a signal transmitted in a balanced manner via the signal line unit into an AC signal component having a predetermined frequency;
A bandpass filter configured to allow a component of a predetermined band including the predetermined frequency to pass through the output signal of the DC / AC conversion circuit;
A differential amplifier that receives and amplifies the output of the bandpass filter as a differential input;
The DC / AC conversion circuit includes:
The first and second input terminals, the first and second output terminals, and the first and second input terminals are connected to the first and second signal lines, respectively. A four-terminal variable capacitor configured such that the capacitance value between the output terminals can be varied;
A first integration circuit for integrating a voltage between the first output terminal of the four-terminal variable capacitor and a ground line;
A second integrating circuit for integrating a voltage between the second output terminal of the four-terminal variable capacitor and the ground line;
An atmospheric electric field detection device, wherein a capacitance value between the first and second output terminals of the four-terminal variable capacitor is varied with the predetermined frequency. The atmospheric electric field detection device according to claim 9,
The four-terminal variable capacitor is
A vibrating electrode connected to the first output terminal;
A fixed electrode connected to the second output terminal,
An atmospheric electric field detection device configured to be able to vary a capacitance value between the first and second output terminals by vibrating the vibrating electrode.

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