JP5023332B2 - Vacuum arc discharge generation method - Google Patents

Description

  The present invention, for example, detects information such as the influence of a discharge phenomenon on the surface of a solar cell array in order to reduce damage to the solar cell due to a discharge phenomenon that occurs in a solar cell array mounted on an artificial satellite orbiting space. The present invention relates to a method for generating a vacuum arc discharge.

  In recent years, spacecraft such as artificial satellites require a large amount of power, and accordingly, the power used is becoming higher voltage. For this reason, discharge phenomena have frequently occurred in solar cell arrays mounted on satellites. In order to prevent accidents caused by the discharge of the solar cell array, we are currently conducting ground tests on the discharge phenomenon occurring on the solar cell array and its effects before the launch of the spacecraft. When the solar array is tested on the ground, a coupon simulating the dielectric of the solar cell of the solar array is prepared in consideration of the orbital environment of the spacecraft, and an electron beam or plasma is applied to the coupon. Conducting a charge / discharge test. In the band discharge test using an electron beam, the time required for the discharge test is long because the frequency of occurrence of discharge to the coupon is low. In addition, since the discharge to the solar cell array is generated everywhere the dielectric in the solar cell array is charged, that is, everywhere, it is difficult to generate the discharge at an arbitrary place. When a discharge is generated using plasma on a dielectric, the discharge frequency increases, but it is difficult to control the discharge at a predetermined position on the dielectric.

  In general, in a discharge test for a dielectric coupon in a vacuum simulating a space environment, an automatic method is used in which a dielectric is charged using plasma or an electron beam. As an active method, there is a method in which a current is passed through a thin resistance wire and plasma generated when it burns out is used. However, it is necessary to replace the resistance wire after a single discharge.

  Conventionally, space solar cell arrays are known. The solar cell array includes a large number of solar cells connected by an interconnector provided on a substrate, and a transparent cover member bonded on the solar cells, and the surface of the cover member is provided. The conductive film is covered with a transparent conductive film, and the conductive film and the interconnector are electrically connected (for example, see Patent Document 1).

  A plasma generator using three-phase alternating current is also known. The plasma generator has a long filament excitation length exceeding 1 m, and can realize a uniform plasma density in space and time with an inexpensive power source. Straight filaments are stretched in the longitudinal direction of the chamber so that the three filaments forming a pair form an equilateral triangle, and one end of each of the three filaments forming the pair is connected to three terminals of a three-phase alternating current, and the other end is connected They are collectively connected to an arc power source (see, for example, Patent Document 2).

  In addition, a solar battery power supply device mounted on a space vehicle such as an artificial satellite is known. The solar cell power supply device includes a plurality of radiation detectors for detecting radiation caused by solar protons contained in the solar flare, and the orientation of the light receiving surface of the solar cell array based on the output of the solar cell power supply device when no solar flare occurs. And a solar cell array driving device that drives the laser beam in a direction that minimizes radiation exposure (see, for example, Patent Document 3).

In addition, a surface treatment apparatus that uses a creeping discharge with a high treatment rate and has little damage to an object to be treated is known. The surface treatment apparatus using the creeping discharge includes a creeping discharge electrode including a first electrode and a second electrode arranged with a dielectric interposed therebetween. An AC power supply is connected to the first electrode, and the grounded second electrode has an opening. A surface discharge is induced in a region in the vicinity of the opening, and the surface of an object to be processed that is disposed in close proximity to the second electrode is treated by the active species generated by the surface discharge (for example, a patent) Reference 4).
JP-A-61-202475 JP 2000-12282 A Japanese Patent Laid-Open No. 6-8894 Japanese Patent Laid-Open No. 9-186135

  However, when an arc discharge is generated in a vacuum on a dielectric, it is necessary to charge the dielectric and wait for an accidental discharge using an electron beam or plasma. The efficiency of the discharge test was poor because it was not possible to generate a discharge at a predetermined time. By the way, there is a possibility that discharges occur at any location on the solar cell array. However, in order to evaluate the influence of the location of the discharge in the solar cell array on the solar cell array, the discharge must be generated at many locations. In other words, it takes a long time to discharge the dielectric material many times, and the duration of the discharge test becomes longer. In order to improve these problems, there is a demand for a discharge test apparatus capable of generating a discharge at a predetermined position and a predetermined time of a dielectric for an electric device such as a solar cell array.

  An object of the present invention is to solve the above-mentioned problems, and requires a large-scale apparatus such as an electron beam gun or a plasma source in order to generate a vacuum arc discharge to a dielectric of an electric device such as a solar cell array. Instead, a discharge can be generated at a predetermined time in a predetermined place of the dielectric, thereby causing a discharge effect on the dielectric, a region where the dielectric discharge is likely to occur, and the dielectric A method of generating a vacuum arc discharge that can detect a region that is easily charged, can quickly achieve a discharge test in a short time and at low cost, and can secure information for improving the structure of the dielectric along with the information. Is to provide.

The present invention, in the electrical equipment in the vacuum arc discharge generating method for generating an arc discharge in a vacuum against chargeable dielectric, the two relatively movable spaced state to the surface of said derivative collector the needle electrodes were disposed, the directly to the surface of the derivative collector or indirect contacting, the surface discharge by applying a high voltage pulse between said needle electrodes in said derivative collector surface between the needle electrodes The present invention relates to a method for generating a vacuum arc discharge, characterized in that a vacuum arc discharge is induced through plasma generated by the creeping discharge on the dielectric.

  In this vacuum arc discharge generating method, an insulator such as a cover glass having a heat dissipation function and a protection function can be interposed between the dielectric and the needle electrode.

  In this method of generating a vacuum arc discharge, the high voltage applied between the needle electrodes is several tens of kV, which is set to a high voltage by a booster.

  In this vacuum arc discharge generation method, the electrical device is a solar cell of a solar cell array that can be attached to an artificial satellite housed in a vacuum chamber that simulates a space environment.

  Further, in this vacuum arc discharge generating method, by applying the high voltage pulse between the needle electrodes, a discharge is generated between the needle electrode and the dielectric or the cover glass on the dielectric, and the The creeping discharge is generated on the dielectric or the cover glass, and then enters the plasma state by the creeping discharge, and a vacuum is generated between the solar cell of the dielectric and the wall of the vacuum chamber via the plasma. Arc discharge occurs.

  Further, in this vacuum arc discharge generating method, the needle electrode is moved relative to the dielectric, and the needle electrode is set in a predetermined region where a vacuum arc discharge should be generated with respect to the dielectric. can do. Further, this vacuum arc discharge generating method is characterized in that the high voltage pulse is applied between the needle electrodes to generate the vacuum arc discharge to the dielectric, and the discharge influence and / or accumulation in the region of the dielectric. The amount of charge can be detected.

  In addition, this vacuum arc discharge generation method generates a vacuum arc discharge on the dielectric by moving the needle electrode relative to the dielectric and applying the high voltage pulse between the needle electrodes. An easy region can be detected.

  In this method of generating a vacuum arc discharge, the discharge state is detected through a monitoring window provided in the vacuum chamber by an IR camera that forcibly projects the monitoring range by irradiating infrared light installed outside the vacuum chamber. It can be taken.

  Since this vacuum arc discharge generation method is configured as described above, a large-scale device such as an electron beam or a plasma gun for generating a vacuum arc discharge for a dielectric of an electric device such as a solar cell array. In this way, a vacuum arc discharge is generated in a predetermined predetermined place and at a predetermined time in a short time and at a low cost, and information such as the influence of the discharge on the dielectric is detected. This can contribute to the improvement of electric devices such as solar cell arrays.

  Embodiments of a vacuum arc discharge generating method according to the present invention will be described below with reference to the drawings. In the vacuum arc discharge generating method according to the present invention, a coupon 2 is disposed in a vacuum chamber 1 that simulates a space environment, with respect to a coupon 2 that is originally manufactured as a dielectric of an electric device such as a solar cell array that can be charged. , The dielectric coupon 2 is characterized in that arc discharge is easily and inexpensively generated in a vacuum. A solar cell array mounted on a spacecraft flying in space may be charged and discharged between the solar cell array and the electrode when light from space hits its dielectric. It may cause damage or malfunction. Therefore, this method of generating vacuum arc discharge has an effect on the electric device such as a solar cell array in which the dielectric of the electric device is easily charged, the discharge effect when the dielectric is discharged in a charged state or in an uncharged state, etc. It can be applied to verify. The solar cell array is composed of a large number of solar cells connected by interconnectors provided on a substrate.

  In this vacuum arc discharge generation method, a coupon 2 of a test sample prepared as a dielectric of an electric device such as a solar cell array is mainly disposed in a vacuum in a vacuum chamber 1 simulating a vacuum atmosphere, that is, a vacuum environment. Two needle electrodes 5 are forcibly brought into contact with the coupon 2 indirectly / directly, and a high voltage pulse obtained by boosting the power supplied from the power source 4 by the booster 7 is applied between the needle electrodes 5. 5, a creeping discharge is generated along the surface of the coupon 2 between the needle electrodes 5 by a high voltage pulse applied between 5, and plasma is generated in the region by the creeping discharge, and then the coupon 2 and the vacuum chamber 1 are passed through the plasma. This is characterized in that a vacuum arc discharge is induced in the dielectric coupon 2 by short-circuiting with the other wall. At this time, the needle electrode 5 has a diameter of about 0.2 mm, for example. Further, the two needle electrodes 5 are installed so as to be kept in a separated state at a predetermined distance, for example, about 0.1 mm, so that the needle electrodes 5 do not contact each other.

  Further, in this vacuum arc discharge generating method, an insulator such as a cover glass 3 having a heat radiation function and a protection function can be interposed between the coupon 2 and the needle electrode 5. By interposing the cover glass 3 between the needle electrode 5 and the coupon 2, unnecessary light can be reflected so as not to contribute to the discharge. In this vacuum arc discharge generation method, when the cover glass 3 is interposed between the coupon 2 and the needle electrode 5, the creeping discharge is generated along the surface of the cover glass 3. In this vacuum arc discharge generating method, the coupon 2 is composed of solar cells in a solar cell array and electrodes (not shown) arranged on both sides thereof. When the cover glass 3 is interposed between the coupon 2 and the needle electrode 5, it is preferable to arrange the electrodes on the cover glass 3 side in a comb-like shape. When an insulator such as a cover glass 3 is interposed in the coupon 2, that is, the discharge object, the needle electrode 5 is arranged on the insulator and creeping discharge is generated as an assembly in which the insulator and the needle electrode 5 are integrated. It can be used as a device and can be disposed at a location where a discharge object is desired to be discharged to generate a discharge. For example, the cover glass 3 has a thickness of about 100 μm. The plate thickness of the solar battery cell is approximately 100 μm, like the cover glass 3.

  This vacuum arc discharge generating method is configured such that the needle electrode 5 is moved relative to the dielectric coupon 2 and a predetermined predetermined place where the vacuum arc discharge should be generated with respect to the coupon 2 can be selected. ing. That is, in this vacuum arc discharge generating method, the needle electrode 5 is installed at a portion where a discharge is to be generated on the dielectric coupon 2, and therefore the needle electrode 5 is relative to the entire area of the coupon 2. It is necessary to install it so that it can be moved. The needle electrode 5 is supported by electrode support bars 10 and 11 as shown in FIG. Therefore, in order to move the electrode support rods 10 and 11 relative to the coupon 2 in a three-dimensional manner, a conventionally known linear motion guide bearing, a positioning device including an XYZ axis and a rotation axis is used. It is preferable to install. In a laboratory or the like, it is needless to say that the needle electrode 5 or the coupon 2 may be moved manually.

  Moreover, in this vacuum arc discharge generating method, the high voltage applied between the needle electrodes 5 can be, for example, several tens of kV made high by the booster 7. The booster 7 can energize the power from the power source 4 by connecting / disconnecting the switch 6. A vacuum arc discharge generator for achieving this vacuum arc discharge generation method is a sample simulating a solar cell housed in a vacuum chamber 1 simulating a space environment, that is, a coupon 2, and a coupon 2 and a needle electrode 5 The insulator interposed between the two uses a cover glass 3.

  In this method of generating a vacuum arc discharge, when a discharge is first applied between the needle electrodes 5 in contact with the cover glass 3, a creeping discharge is generated on the surface of the cover glass 3, and then the coupon 2 and the cover are covered. This occurs between the glass 3 and the region is in a plasma state, where it reaches the wall of the coupon 2 and the vacuum chamber 1 where the discharge is charged through the plasma, that is, through the plasma, and a vacuum arc discharge occurs. In other words, this vacuum arc discharge generation method induces a vacuum arc discharge in the coupon 2 through plasma generated by creeping discharge, and thereby information on the effect on the generation area of the vacuum arc discharge in the coupon 2, that is, the solar cell. Can be detected. When the solar cell performs arc discharge, it occurs in the vicinity of the outer peripheral end face of the solar cell. Therefore, in this vacuum arc discharge generation method, the needle electrode 5 is relatively moved along the peripheral edge of the coupon 2 and is easily discharged. The location can be detected, and the influence of the discharge can be verified.

  In this method of generating a vacuum arc discharge, the discharge can be photographed through a monitoring window 8 provided in the vacuum chamber 1 by an IR camera 9 that forcibly projects the monitoring range brightly by infrared light irradiation installed outside the vacuum chamber 1. The information captured by the IR camera 9 is processed by the computer / personal computer 13, and for example, a discharge current / voltage waveform intentionally generated can be detected as shown in FIG. Further, in this method of generating a vacuum arc discharge, a high voltage pulse is applied between the needle electrodes 5 to generate a vacuum arc discharge on the coupon 2, so that the discharge effect and / or accumulated charge in the region is applied to the coupon 2. The amount can be detected. Further, in this vacuum arc discharge generating method, the needle electrode 5 is moved relative to the coupon 2 and a high voltage pulse is applied between the needle electrodes 5 to generate a vacuum arc discharge on the coupon 2. It is possible to detect a region where vacuum arc discharge is likely to occur.

-Outline of experiment-
In this vacuum arc discharge generating method, when the surface of the cover glass 3 is charged by applying a high voltage pulse to the needle electrode 5, a reverse potential gradient is generated between the solar battery cell 2 and the cover glass 3 surface. Then, electrons are ejected from the interconnector by field emission, and the electrons strike the side surface of the cover glass 3 to generate collision secondary electrons and degassing, and the side surface of the cover glass 3 is charged. As a result, the electric field is further strengthened, and dielectric breakdown occurs between the cover glass 3 and the coupon 2 and it is considered that the first discharge occurs. Next, the charge stored in the capacitance of the spacecraft and the outer space is discharged by the first discharge, and then the charge stored in the cover glass 3 other than the discharge location is also discharged.

  It was considered that the subsequent discharge can be generated by generating the first discharge that occurs between the cover glass 3 and the coupon 2. Therefore, we developed a discharge generation method that intentionally generates plasma at the place where discharge is desired to induce discharge. As a method for this, as shown in FIG. 1, a high voltage is applied to the needle electrode 5 by using a booster 7, and creeping discharge is generated along the surface of the cover glass 3. In this experiment, a solar cell coupon 2 is installed in the vacuum chamber 1 to simulate a space environment. In the experimental apparatus that achieves this method of generating vacuum arc discharge shown in FIG. 1, the solar cell array is charged everywhere and becomes charged as a power supply unit 12 for vacuum arc discharge. The capacitor Cext simulates the charge stored in the other cover glass 3 because the actual size solar cell array cannot be put in the vacuum chamber 1. Further, the potential of the artificial satellite with respect to the peripheral plasma is simulated by the high voltage power source Vbias. When the discharge occurs, electrons are emitted from the capacitor Cext, pass through the coupon 2 simulating the solar cell array, reach the wall of the vacuum chamber 1 via the discharge plasma, and a current flows to the ground. Measure this current (blow-off current) with a current probe and confirm that a discharge has occurred. The discharge generated in the vacuum chamber 1 was photographed from the monitoring window 8 using the IR camera 9. Information captured by the IR camera 9 can be processed by a computer / personal computer to obtain voltage / current waveforms.

  In order to generate discharge at a predetermined predetermined position of the solar cell coupon 2, that is, at an arbitrary position, tungsten is used as the two needle electrodes 5, and the needle electrodes 5 are placed at the positions where the discharge is desired. In order to prevent the 5 members from touching each other, they are installed at a distance of about 0.1 mm. The switch 6 of the booster 7 is turned on at a predetermined time, that is, an arbitrary time, and a high voltage pulse is generated by the power from the power source 4 to generate a discharge.

  FIG. 3 shows an example of a discharge waveform obtained by the experiment as a result of the experiment on the vacuum arc discharge generation method. 3, the elapsed time (μS) is taken on the horizontal axis, the voltage waveform (kV) and the current waveform (A) are taken on the vertical axis, the voltage waveform is shown by the symbol VP, and the current waveform is shown by the symbol CP. In particular, it is possible to confirm the state in which the vacuum arc discharge is generated in the area of the symbol ED. It can be confirmed that the blow-off current flows at the same time as the bias voltage Vbias suddenly rises to 0V. That is, by applying a high pressure by the booster 7, it was possible to generate a discharge at an arbitrary position and time in the vacuum in the vacuum chamber 1 simulating the space environment.

  The vacuum arc discharge generation method according to the present invention, for example, generates a plasma state by generating a creeping discharge for an electric device such as a solar cell of a solar cell array, and generates a vacuum arc discharge through the plasma. It is preferably applied to a discharge test and vacuum discharge for detecting information such as a discharge effect on an electric device such as a solar battery cell.

It is explanatory drawing which shows one Example of the circuit diagram of the vacuum arc discharge generator for achieving the vacuum arc discharge generation method by this invention. It is explanatory drawing which shows the relationship between the needle electrode and cover glass in the circuit diagram of FIG. It is a discharge waveform diagram which shows an example of the waveform of the voltage and electric current of the arc discharge obtained by this vacuum arc discharge generating method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Solar cell coupon 3 Cover glass 4 Power supply 5 Needle electrode 6 Switch 7 Booster 8 Monitoring window 9 IR camera 10 Electrode support rod 11 Electrode support rod 12 Power supply part of vacuum arc discharge 13 Computer / PC

Claims (9)

In a vacuum arc discharge generating method for generating an arc discharge in a vacuum with respect to a chargeable dielectric of an electric device,
Wherein disposed two needle electrodes relatively movable spaced state to the surface of the induction conductor, the directly to the surface of the derivative collector or indirect contacting, high voltage between said needle electrode by applying a pulse to generate a surface discharge in the derivative collector surface between the needle electrodes, wherein the inducing vacuum arc discharge through the plasma generated by the surface discharge to the dielectric Vacuum arc discharge generation method.   2. The vacuum arc discharge generating method according to claim 1, wherein an insulator such as a cover glass having a heat dissipation function and a protection function is interposed between the dielectric and the needle electrode.   The method of generating a vacuum arc discharge according to claim 1 or 2, wherein the high voltage applied between the needle electrodes is several tens of kV, which is set to a high voltage by a booster.   The vacuum according to any one of claims 1 to 3, wherein the electrical device is a solar cell of a solar cell array that can be attached to an artificial satellite housed in a vacuum chamber that simulates a space environment. Arc discharge generation method.   By applying the high voltage pulse between the needle electrodes, a discharge is generated between the needle electrode and the dielectric or the cover glass on the dielectric, and the creeping surface is formed on the dielectric or the cover glass. A discharge is generated, and then a plasma state is generated by the creeping discharge, and a vacuum arc discharge is generated between the solar cell of the dielectric and the wall of the vacuum chamber through the plasma. The vacuum arc discharge generating method according to claim 4.   The discharge state can be photographed through a monitoring window provided in the vacuum chamber by an IR camera that forcibly projects the monitoring range brightly by infrared light irradiation installed outside the vacuum chamber. 5. The method for generating a vacuum arc discharge according to 5.   2. The needle electrode is set in a predetermined region where the needle electrode is moved relative to the dielectric and a vacuum arc discharge is to be generated on the dielectric. The vacuum arc discharge generating method according to any one of 6.   The high voltage pulse is applied between the needle electrodes to generate the vacuum arc discharge with respect to the dielectric, and the discharge influence and / or accumulated charge amount in the region of the dielectric is detected. The vacuum arc discharge generating method according to claim 7.   The needle electrode is moved relative to the dielectric, and the high voltage pulse is applied between the needle electrodes to detect a region where the vacuum arc discharge is likely to occur with respect to the dielectric. The method of generating a vacuum arc discharge according to any one of claims 1 to 8.

Images