CN103604979A - Detector based on capacitor voltage distribution and detecting method thereof - Google Patents

Abstract

The invention relates to proposing a detector based on capacitive voltage division and its detection method. The detector includes a conductive measuring electrode and an insulating film pasted thereon. The voltage measurement circuit performs measurement, and the compensation electrode is arranged on the periphery of the conductive measurement electrode and is isolated from the conductive measurement electrode. The invention does not need complex long extension rod mechanism, voltage scanning circuit and voltage and current curve processing program, can directly obtain the floating potential value, has simple design and high reliability.

Description

A detector based on capacitive voltage division and its detection method

technical field

The invention belongs to the technical field of space environment detection applications, and in particular relates to a detector based on capacitive voltage division and a detection method thereof.

Background technique

The spacecraft will interact with the space plasma in the space environment. Since the electron speed is faster than the ion, the charging potential of the spacecraft is mainly negative. The electrostatic discharge of the spacecraft due to the charging effect of the space plasma is caused by the fact that the charging speed and equilibrium potential of the spacecraft structural conductor are different from the charging speed and equilibrium potential of the spacecraft surface dielectric material, resulting in different Equal charge. In order to ensure the active control of the electrostatic discharge effect of the spacecraft in orbit, it is necessary to have corresponding detection means.

At present, the detection method for the floating potential of spacecraft is mainly used on scientific satellites, and it is realized by placing probes on long extension rods. Probes can use Langmuir probes, space electric field probes, and launch probes to achieve the purpose of detecting the floating potential of the spacecraft. Among them, the Langmuir probe uses the scanning voltage loaded on the probe to obtain the collection current curve, and obtains the suspension potential according to the corresponding theoretical model; the space electric field probe is used to measure the space potential, and obtains the electric field according to the distance of the probe at different positions of the extension rod , can also be used to analyze the potential of the spacecraft; the emission probe emits electrons through the hot wire, and adjusts the potential difference of the probe relative to the space environment. When the adjustment value reaches the suspension potential, its collection current will be generated by thermionic emission Jump, so as to obtain the floating potential. The above-mentioned technologies have several things in common. Firstly, they all need a longer extension rod, which makes them have certain requirements for the spacecraft. Secondly, the above-mentioned methods all use voltage scanning and indirect measurement, and the design is relatively complicated. It is difficult to realize the corresponding means under the requirement of high reliability. In addition, due to the complex design of the instrument, its weight and power consumption are also relatively large. For this reason, it is necessary to provide a method for detecting the floating potential of spacecraft with simple structure, convenient use, light weight and low power consumption.

Contents of the invention

Aiming at the above technical problems, the present invention proposes a detector based on capacitive voltage division and its detection method by using the capacitive voltage division method and the principle that the conductor and the medium respectively establish a balance process in the plasma environment. The present invention is simple in design and can Directly measure the suspension potential, and at the same time, there is no high requirement for the extension rod, which can be realized by using a shorter extension rod.

For achieving above object, the technical scheme that the present invention adopts is:

A detector based on capacitive voltage division, including a conductive measuring electrode and an insulating film pasted on it. The conductive measuring electrode is connected to the structural ground of the spacecraft with a measuring capacitor, and is measured by a voltage measuring circuit. The compensation electrode is arranged in The conductive measurement electrodes are peripheral and isolated from the conductive measurement electrodes.

Further, the compensation electrode is structurally connected to the spacecraft through a protection resistor and a bias voltage source.

A method for detecting the floating potential by using the detector. The equivalent capacitance of the insulating film and the measurement capacitance form a capacitance voltage divider network, adjust the switch circuit in the measurement capacitance to control its capacitance, and use the voltage measurement circuit to obtain two The voltage measurement value corresponding to the group, by knowing the capacitance value of the measurement capacitance and the measurement voltage value, the equivalent capacitance of the insulating film can be determined, according to the value of the equivalent capacitance of the insulation film, the capacitance value of the measurement capacitance and the measurement voltage value , to determine the value of the suspension potential.

Further, the measured value of the equivalent capacitance of the insulating film is calibrated by using switches to switch two groups of different measured capacitance values at regular intervals, and the floating potential value is obtained by using this value and the determined and unchanged measured capacitance.

The detector and its detection method based on capacitive voltage division of the present invention do not require complex long extension rod mechanisms, voltage scanning circuits and voltage and current curve processing procedures, and can directly obtain the floating potential value, with simple design and high reliability.

Description of drawings

Fig. 1 is a schematic diagram of the composition of the detector of the present invention.

Figure 2 is an equivalent schematic diagram of the floating potential detection.

Among them, 1. Insulating film; 2. Conductive measuring electrode; 3. Compensating electrode; 4. Measuring capacitance; 5. Voltage measuring circuit; 6. Bias voltage source; 7. Spacecraft structural ground; Equivalent capacitance of insulating film; 10. Measured voltage value; 11. Suspension potential value.

Detailed ways

The following is a specific implementation manner of the content of the present invention, and the content of the present invention will be further clarified through the specific implementation mode below. Of course, the following specific embodiments are described only to illustrate different aspects of the present invention, and should not be construed as limiting the scope of the present invention.

As shown in Figure 1, a kind of detector based on capacitive voltage division, it comprises conductive measuring electrode 2 and the insulating film 1 pasted thereon, is connected with measuring capacitor 4 between conductive measuring electrode 2 and spacecraft structure ground 7, The voltage measurement circuit 5 is used for measurement, and the compensation electrode 3 is arranged on the periphery of the conductive measurement electrode 2 and is isolated from the conductive measurement electrode 2 . The compensation electrode 3 is connected to the spacecraft structural ground 7 through a protection resistor 8 and a bias voltage source 6 .

The detector can be placed on the outer surface of the spacecraft. When the spacecraft is charged due to the influence of space plasma, the ground 7 of the conductive structure of the spacecraft will generate a relatively negative potential, but due to the effect of the dielectric film on the surface of the conductive measurement electrode, its dielectric The outer surface potential of the layer is approximately equal to the space plasma potential. At this time, the equivalent capacitor 9 of the insulating film and the measuring capacitor 4 form a capacitive voltage divider network, adjust the switching circuit in the measuring capacitor 4 to control its capacitance, and use the voltage measuring circuit 5 to obtain two sets of corresponding voltage measurement values. By knowing the capacitance value of the measurement capacitance 4 and the measurement voltage value 10, the equivalent capacitance 9 of the insulating film can be determined. According to the value of the equivalent capacitance 9 of the insulation film, the capacitance value of the measurement capacitance 4 and the measurement voltage value 10, The floating potential value 11 can be determined. Specifically, the floating potential of the spacecraft is approximately equal to the potential difference U _f between the outer surface potential of the dielectric layer and the structural ground of the spacecraft, where the dielectric film itself can be equivalent to the capacitance value between the space plasma and the conductive measurement electrode C1, the measurement capacitor C2 is connected between the conductive measurement electrode and the spacecraft structure ground potential. When the spacecraft is charged to a certain levitation potential in the plasma environment, the measured voltage value between the conductive measurement electrode and the spacecraft structure ground is U _m . According to the capacitor voltage divider method, it can be known that:

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="C"\; filenames="HDA0000426342560000012.png"\; state="\{\{state\}\}">C</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}$

Among them, when changing two sets of different C2 values, the size of C1 and the value of U _f can be obtained by measuring the voltage U _m and the value of capacitance C2. After the C1 value is obtained through measurement, the suspension potential value can be directly measured without changing the value of C2.

During the measurement, since the space plasma will change with the orbital position of the spacecraft, the measured value of C1 is calibrated by switching two sets of different C2 values at regular intervals, and the measured value of C1 is obtained by using this value and the determined and unchanged measuring capacitance 4 The floating potential value is 11 to reduce the number of times the switch in the measurement capacitor 4 is used and increase its service life on the rail.

During measurement, when there are other exposed conductors on the outer surface of the spacecraft near the conductive measuring electrode 2 , the voltage of the compensation electrode 3 can be adjusted, and the peripheral size of the compensation electrode 3 is larger than that of the conductive measuring electrode 2 . When the compensation voltage is approximately the same as the space plasma potential, the influence of the surrounding sheath can be reduced. By applying the measured value to the compensation electrode 3 as a bias voltage relative to the spacecraft structure, the purpose of eliminating the surrounding interference is achieved. Feedback can be formed, and the measured value after the interference is eliminated continues to be used as a new bias voltage until the measured value stabilizes in a short time.

Although the specific embodiments of the present invention have been described and illustrated in detail above, it should be noted that those skilled in the art can make various equivalent changes and modifications to the above embodiments according to the spirit of the present invention, and the resulting When the functional effect does not exceed the spirit covered by the specification and drawings, it shall be within the protection scope of the present invention.

Claims (4)

1. A detector based on capacitive voltage division, characterized in that it includes a conductive measuring electrode (2) and an insulating film (1) pasted thereon, the conductive measuring electrode (2) and the spacecraft structural ground (7) They are connected with a measuring capacitor (4) and measured by a voltage measuring circuit (5). The compensation electrode (3) is arranged on the periphery of the conductive measuring electrode (2) and is isolated from the conductive measuring electrode (2). 2. The detector according to claim 1, characterized in that the compensation electrode (3) is connected to the spacecraft structural ground (7) through a protection resistor (8) and a bias voltage source (6). 3. A method for detecting the floating potential by using the detector according to any one of the preceding claims, characterized in that, the equivalent capacitance (9) of the insulating film and the measurement capacitance (4) form a capacitive voltage divider network, Adjust the switch circuit in the measurement capacitor (4) to control its capacitance, and use the voltage measurement circuit (5) to obtain two sets of corresponding voltage measurement values. By knowing the capacitance value of the measurement capacitor and the measurement voltage value (10), it can be determined The equivalent capacitance (9) of the insulating film is obtained, and the suspension potential value (11) is determined according to the value of the equivalent capacitance (9) of the insulating film, the capacitance value of the measured capacitance and the measured voltage value (10). 4. the method for floating potential detection as claimed in claim 3 is characterized in that, adopt switch to switch two groups of different measuring capacitance values at intervals to calibrate the measured value of insulating film equivalent capacitance, and use this value and determined , The floating potential value (11) is obtained from the unchanged measured capacitance (4).

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