Pulse superposition direct current excitation rare gas glow discharge device

Abstract

The invention discloses a pulse superposition direct current excitation rare gas glow discharge device, which comprises an electrode module, a power supply module and an integration module, wherein the power supply module is used for receiving the input of direct current and processing direct current voltage to respectively form high-voltage current and rectangular pulse for output; the integration module is used for receiving the high-voltage current and the rectangular pulse so as to respectively act on the first electrode and the second electrode of the electrode module in a coupling manner; through cooperative cooperation of the power supply module and the integration module, a composite excitation electric field with direct current bias and pulse enhancement effects is formed between the first electrode and the second electrode, a high-voltage current component maintains discharge self-sustaining, and a matrix pulse component can improve the peak electric field by 30-50% to better excite high-energy electron collapse, so that the high-energy electron collapse is enhanced. Through the synergistic effect of the two, the glow discharge current is stabilized at 2-10mA, the plasma density uniformity is greater than 85%, and a stable and efficient electric field is effectively obtained to ionize gas.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of gas detection, in particular to a rare gas glow discharge device excited by pulse superposition direct current. BACKGROUND

[0002] Argon as an inert gas has strong application in industry; in the preparation of hollow glass, argon needs to be filled in the cavity formed by two glass panels, argon is one of inert gases, and its chemical properties are very stable. It is colorless, odorless, and does not react with other substances at room temperature, it cannot burn, nor can it help combustion, and it is also very safe, therefore, argon filling in hollow glass has a relatively positive effect on heat insulation, filtering ultraviolet rays, preventing fogging, reducing the probability of self-explosion, sound insulation, firmness and prolonging the service life of the product; however, if the argon concentration does not reach the expected value, it will cause the quality of the hollow glass to decrease, therefore, it is necessary to measure the argon parameters of the hollow glass; in the conventional detection scheme, the argon concentration parameters are detected by argon detection instruments, the general mechanism is as follows: first, a gas discharge device is used to generate an electric field with sufficient energy, so that the argon forms ionization and produces glow, and the spectral distribution of the glow is analyzed by a sensor to obtain the content of argon; the traditional gas discharge device has limitations in pulse uniformity, voltage excitation mode and parameter stability: the energy of pure direct current discharge is insufficient, the waveform distortion or energy fluctuation of conventional pulse discharge is easy to occur, and most devices rely on complex boost structure, it is difficult to realize stable high voltage output in a wide range under low direct current input, it can be seen that the output pulse of the discharge device in the prior art is not uniform, and the excitation stability is poor; therefore, a more reasonable scheme is needed to solve the problems and disadvantages in the prior art. SUMMARY

[0003] In view of the technical problems of the discharge device of the argon detector in the prior art, such as insufficient energy of pure direct current discharge, easy waveform distortion or energy fluctuation of conventional pulse discharge, and difficulty in realizing stable high voltage output in a wide range under low direct current input, the present application provides a solution.

[0004] To achieve the above-mentioned purpose, the present application provides a rare gas glow discharge device excited by pulse superposition direct current, comprising:

[0005] An electrode module;

[0006] A power module for receiving input of direct current and processing direct current voltage to form high voltage current and rectangular pulse respectively for output;

[0007] An integration module is configured to receive the high-voltage current and the rectangular pulse to be coupled to a first electrode and a second electrode of the electrode module respectively, so that a composite excitation electric field is formed between the first electrode and the second electrode.

[0008] As an improved scheme of the present application, the power module comprises:

[0009] A high-voltage direct-current power supply circuit is configured to process an input current to output the high-voltage current.

[0010] A nanosecond pulse power supply circuit is configured to process another input current to form the matrix pulse.

[0011] As an improved scheme of the present application, the high-voltage direct-current power supply circuit comprises a high-frequency transformer, a switch tube and a PWM unit; wherein the primary coil of the high-frequency transformer is coupled to the switch tube and the PWM unit.

[0012] The forming step of the high-voltage power supply is as follows:

[0013] The input current is input to the high-frequency transformer, the primary coil of the high-frequency transformer is driven by the switch tube, and then the duty cycle of the switch tube is modulated and controlled by the PWM unit to output the high-voltage current from the secondary coil of the high-frequency transformer.

[0014] As an improved scheme of the present application, the high-voltage direct-current power supply circuit further comprises a filter unit and a feedback unit, and the filter unit and the feedback unit are respectively coupled to the output end of the high-frequency transformer.

[0015] As an improved scheme of the present application, the nanosecond pulse power supply circuit comprises a voltage regulator, a charging resistor, a transformer, a switch and a non-inductive load resistor; wherein the output end of the voltage regulator is coupled to the charging resistor, one end of the charging resistor away from the voltage regulator is coupled to the transformer through a coaxial cable, and the other end of the transformer away from the charging resistor is coupled to the non-inductive resistor.

[0016] The forming step of the matrix pulse is as follows:

[0017] Primary energy storage: the other input current is first stepped down by the voltage regulator, and then the charging resistor charges the coaxial cable to store a uniform energy field;

[0018] Secondary voltage boosting and pulse rectification: the switch is closed to trigger the coaxial cable to discharge to obtain a pulse, and the pulse is boosted by the transformer and then suppressed by the non-inductive load to output a uniform matrix pulse.

[0019] As an improved scheme of the present application, the integration module comprises a direct current channel circuit and a pulse channel circuit:

[0020] The direct current channel circuit is used to apply the high-voltage current to the first electrode and the second electrode;

[0021] The pulse channel circuit is used to couple the rectangular pulse to the first motor and the second motor to form the composite excitation electric field.

[0022] As an improved scheme of the present application, the direct current channel circuit is composed of a current-limiting inductor of a current-limiting resistor coupled in sequence;

[0023] The high-voltage current passes through the current-limiting resistor and the current-limiting inductor in sequence so that the current applied to the first electrode and the second electrode is within 2-10 mA.

[0024] As an improved scheme of the present application, the pulse channel circuit comprises an isolation bridge; the pulse passes through the isolation bridge in sequence and is coupled to the first electrode and the second electrode.

[0025] As an improved scheme of the present application, the first electrode is a needle electrode, and the second electrode is a plate electrode matched with the needle electrode.

[0026] As an improved scheme of the present application, the material of the needle electrode is tungsten-copper alloy, and the surface of the plate electrode is plated with a nickel metal layer.

[0027] The beneficial effects of the present application are: compared with the prior art, the pulse superimposed direct current excitation rare gas glow discharge device provided by the present application comprises an electrode module, a power supply module and an integration module: the power supply module is used to receive the input of direct current and process the direct current voltage to form a high-voltage current and a rectangular pulse for output respectively; the integration module is used to receive the high-voltage current and the rectangular pulse to be coupled to the first electrode and the second electrode of the electrode module respectively; through the cooperation of the power supply module and the integration module, a composite excitation electric field with the effects of "direct current bias" and "pulse enhancement" is formed between the first electrode and the second electrode, the high-voltage current component maintains the discharge self-sustaining, the matrix pulse component can improve the peak electric field by 30-50% to better excite the high-energy electron avalanche, and the cooperation of the two can make the glow discharge current stable at 2-10 mA, the plasma density uniformity is >85%, and the stable and efficient electric field is effectively obtained to ionize the gas. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The module block diagram of the present application is shown in the figure;

[0029] Figure 2 Another schematic diagram of the module frame of the present application;

[0030] Figure 3 A circuit schematic diagram of the present application. DETAILED DESCRIPTION

[0031] In order to more clearly illustrate the present application, the present application will be further described below in conjunction with the accompanying drawings.

[0032] In the following description, the example details are given in order to provide a more in-depth understanding of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. It should be understood that the specific embodiments are only used to explain the present application, and are not used to limit the present application.

[0033] It should be understood that when the terms "comprising" and / or "including" are used in the specification, it means that the features, integers, steps, operations, elements, or components described therein are present, but not excluding the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

[0034] In order to solve the above-mentioned technical problems, the present application provides a pulse superimposed DC excitation rare gas glow discharge device, please refer to the accompanying Figure 1 to the accompanying Figure 3 , comprising an electrode module, a power supply module and an integration module: the power supply module is used for receiving the input of DC current, and processing the DC voltage to form high voltage current and rectangular pulse respectively for output; the integration module is used for receiving the high voltage current and the rectangular pulse to be coupled to the first electrode and the second electrode of the electrode module respectively;

[0035] Through the cooperation of the power supply module and the integration module, a composite excitation electric field with "DC bias" and "pulse enhancement" effects is formed between the first electrode and the second electrode, the high voltage current component maintains the discharge self-sustaining, the matrix pulse component can improve the peak electric field by 30-50% to better excite the high-energy electron avalanche, and the two work together to make the glow discharge current stable at 2-10mA, the plasma density uniformity is >85%, and a stable and efficient electric field is effectively obtained to ionize the gas.

[0036] In the present embodiment, the power supply module includes a high-voltage DC power supply circuit and a nanosecond pulse power supply circuit, and the two circuits perform their respective functions, the high-voltage DC power supply circuit is used for processing the input current to output high-voltage current, and the nanosecond pulse power supply circuit is used for processing another input current to form a matrix pulse; it is not difficult to understand that the high-voltage DC power supply circuit and the nanosecond pulse power supply circuit can adapt to wide DC power supply scenarios, effectively adapt to 13-24VDC power supply scenarios, and then through the high-voltage DC power supply circuit and the nanosecond pulse power supply circuit to cope with the above-mentioned low DC power supply scenarios;

[0037] In a specific embodiment, the high-voltage direct-current power supply circuit comprises a high-frequency transformer T1, a switch tube m, and a PWM unit; the primary coil of the high-frequency transformer is coupled to the switch tube and the PWM unit; the high-voltage power supply is formed by the following steps: input current is input to the high-frequency transformer, the primary coil of the high-frequency transformer is driven by the switch tube m, and then the duty cycle of the switch tube is modulated and controlled by the PWM unit to output high-voltage current at the secondary coil of the high-frequency transformer; it is not difficult to understand that the working frequency of the switch tube m is between 50-100 KHz, the ratio of the primary coil to the secondary coil of the high-frequency transformer is 1:200-500, and under this ratio, the duty cycle of the switch tube can be modulated and controlled by the PWM unit to achieve 2-10 kV direct-current voltage boost, and the voltage regulation accuracy is maintained within ±1%, effectively outputting high-voltage current to the integrated module.

[0038] As can be seen, the high-voltage direct-current power supply circuit constructed by the above elements can boost 13-24 VDC input current to 2-10 kV direct current through a high-frequency transformer, and form a stable direct-current electric field (field strength 2-10 kV / cm) between electrodes to provide continuous ionization energy for glow discharge.

[0039] In another specific embodiment, the high-voltage direct-current power supply circuit further comprises a filter unit and a feedback unit, the filter unit and the feedback unit are respectively coupled to the output end of the high-frequency transformer; the filter unit is a coupled rectifier diode D1 and a filter capacitor, and the feedback unit is used to monitor the PWM unit; the filter unit and the feedback circuit cooperate to adjust the conduction time of the switch tube in real time, ensuring that the direct-current output ripple is ≤1%.

[0040] In this embodiment, the nanosecond pulse power supply circuit is composed of a voltage regulator T2, a charging resistor R3, a transformer, a switch, and a non-inductive load resistor R2; the output end of the voltage regulator is coupled to the charging resistor R3, and the end of the charging resistor R3 away from the voltage regulator is coupled to the transformer through a coaxial cable; the end of the transformer away from the charging resistor R3 is coupled to the non-inductive resistor.

[0041] The formation steps of the matrix pulse are as follows:

[0042] Primary energy storage: another input current is first stepped down by the voltage regulator, and then charged to the coaxial cable through the charging resistor R3 to store a uniform energy storage electric field; in a specific embodiment, the charging resistor R3 is a glass glaze resistor with parameters of 200Ω / 5w, and the coaxial cable is two pieces with an impedance of 50 ohms and a length of 10 m; in this stage, the direct-current power supply charges the coaxial cable to the target voltage (0.5-10 kV) through the charging resistor R3, and the coaxial cable is equivalent to a distributed capacitor, realizing uniform distribution of electric charge.

[0043] Secondary voltage boost and pulse rectification: the switch is closed to trigger the coaxial cable discharge to obtain a pulse, the pulse is boosted by the transformer and matched with the inductive load resistor R2 to suppress oscillation to output uniform matrix pulse; the switch has a ball gap structure with a spacing of 0.5 cm, and the closed part is made of brass electrode; the ratio between the primary coil and the secondary coil of the transformer is 1:50, and the resistance value of the inductive load resistor R2 is 100Ω, and the inductance is <1μH; in this stage, after the switch K ball gap structure is broken down, the energy storage of the coaxial cable is fed to the primary coil of the transformer in the form of TEM wave, and the secondary coil induces high voltage pulse (boost ratio 50:1), and after matching with the inductive load resistor R2, the uniform matrix pulse with steep edge and flat top (waveform distortion rate <3%) is output.

[0044] The above electronic components are used to build a suitable matrix pulse generation circuit, which can effectively receive external input power to generate matrix pulses with expected parameters and use them.

[0045] In this embodiment, the integration module includes a direct current channel circuit and a pulse channel circuit:

[0046] The direct current channel circuit is used to apply high voltage current to the first electrode and the second electrode;

[0047] The pulse channel circuit is used to couple a rectangular pulse to the first electrode and the second electrode to form a composite excitation electric field cooperatively;

[0048] The direct current channel circuit and the pulse channel circuit isolate two important outputs, and then cooperatively act on the electrode module to finally form a uniform composite excitation electric field for ionizing rare gases such as argon.

[0049] In a specific scheme, the direct current channel circuit is composed of a current limiting resistor R1 coupled in sequence; the high voltage current passes through the current limiting resistor R1 and the current limiting inductor C1 in sequence so that the current applied to the first electrode and the second electrode is always maintained within 2-10 mA, and the current parameter can be monitored and adjusted in real time through a feedback resistor; the pulse channel circuit includes an isolation bridge; the pulse passes through the isolation bridge and is coupled to the first electrode and the second electrode in sequence; in a specific element parameter, the parameter of the current limiting resistor R1 is 500Ω / 10W; the parameter of the current limiting inductor C1 is 1mH, which can suppress pulse interference and limit the current to 2-10mA at all times; in a preferred scheme, a feedback resistor is also added to monitor and adjust in real time, which facilitates the technician to control; the isolation bridge is an isolation capacitor C2 with a parameter of 1nF / 20kV, which can effectively isolate the influence of direct current; overall, through the design of the inductance (ωL≥10 times the pulse capacitance) of the current limiting resistor R1 and the capacitance (1 / ωC≤1 / 10 times the direct current impedance) of the isolation bridge, the AC / DC signal isolation degree is >40dB, and the pulse waveform distortion rate after superposition is ensured to be <5%.

[0050] As an improved scheme of the present application, the first electrode is a needle electrode, and the second electrode is a plate electrode matched with the needle electrode; the needle electrode and the plate electrode cooperatively form a needle-plate electrode structure, which is widely used in gas ionization and can well face various gases; in a specific scheme, the material of the needle electrode is tungsten-copper alloy, and the surface of the plate electrode is plated with a nickel metal layer, so that the needle electrode can have better high-temperature corrosion resistance, and the plate electrode can have better conductivity, which can ensure that the uniformity of the electric field region is greater than 90% in cooperation with the composite excitation electric field.

[0051] In a further scheme, a quartz glass container (volume 500mL) containing a cavity is further included, the gas inlet of which is connected to a mass flow controller (accuracy ±1% FS) to support accurate gas supply of 0.1-10sccm of He, Ne, Ar and other rare gases; the gas outlet is configured with an ozone decomposer and a gas recovery device to ensure environmental safety.

[0052] As a general embodiment, the embodiment covers all the preferred features described above, and the advantages of the embodiment are: in terms of pulse uniformity, the use of double coaxial cable distributed energy storage, non-inductive load resistance R2, transformer electromagnetic coupling voltage distribution and other technical mechanisms make the output uniform pulse flatness > 95%, amplitude fluctuation < 2%, solving the problem of fast pulse decay and waveform distortion of traditional RLC circuit; in terms of wide-range stable excitation, 13-24VDC low-voltage current input is realized to achieve 2-10kV / 2-10mA AC superimposed output, supporting 100-500ms pulse width continuous adjustment, meeting the multi-scene requirements from low-power surface treatment to high-energy plasma ignition; in terms of reliability, the use of glass enamel resistance and tungsten copper electrode makes the device more stable during use, ensuring the output of parameters.

[0053] Comparative example:

[0054] Table 1

[0055] Parameters The device Conventional device Input voltage 13-24 VDC 220 VAC or high voltage DC Output voltage 2-10 kV (AC superimposed on DC) Single DC or pulsed Pulse width 100-500 ms (adjustable) Fixed or narrow range adjustment Pulse uniformity Flatness > 95% Flatness < 80% Discharge stability Current fluctuation < 3% Current fluctuation > 10%

[0056] As can be seen from Table 1, the present application has more advantages than the traditional device in terms of input voltage, output voltage, pulse width, pulse uniformity and discharge stability, and can obtain better output performance. When applied to rare gas detection, it can better support the detection of test items.

[0057] The advantages of the present application are:

[0058] The above elements are used to construct the resulting high-voltage DC power supply circuit, and the 13-24VDC input current is boosted to 2-10kV DC through a high-frequency transformer to form a stable 2-10kV / cm DC electric field between the electrodes, providing continuous ionization energy for glow discharge.

[0059] The above disclosure is only a few specific embodiments of the present application, but the present application is not limited thereto, and any changes that can be thought of by those skilled in the art shall fall within the protection scope of the present application.

Claims

1. A pulsed superimposed DC-excited rare gas glow discharge device, characterized in that, include: Electrode module; A power module is used to receive DC current input and process DC voltage to form high voltage current and rectangular pulse for output. An integration module is used to receive the high-voltage current and the rectangular pulse, so as to couple them to the first electrode and the second electrode of the electrode module respectively, thereby forming a composite excitation electric field between the first electrode and the second electrode.

2. The pulse superimposed DC-excited rare gas glow discharge device according to claim 1, characterized in that, The power module includes: A high-voltage DC power supply circuit, wherein the high-voltage DC power supply circuit is used to process the input current to output the high-voltage current; A nanosecond pulse power supply circuit is used to process another input current to form the matrix pulse.

3. The pulse superimposed DC-excited rare gas glow discharge device according to claim 2, characterized in that, The high-voltage DC power supply circuit comprises a high-frequency transformer, a switching transistor, and a PWM unit; wherein the primary coil of the high-frequency transformer is coupled to the switching transistor and the PWM unit. The steps for forming the high-voltage power supply are as follows: The input current is input to the high-frequency transformer. The primary coil of the high-frequency transformer coupler is driven by the switching transistor, and then the duty cycle of the switching transistor is modulated and controlled by the PWM unit to output the high-voltage current to the secondary coil of the high-frequency transformer.

4. The pulse superimposed DC-excited rare gas glow discharge device according to claim 3, characterized in that, The high-voltage DC power supply circuit also includes a filter unit and a feedback unit, which are respectively coupled to the output terminal of the high-frequency transformer coupler.

5. The pulse superimposed DC-excited rare gas glow discharge device according to claim 2, characterized in that, The nanosecond pulse power supply circuit consists of a voltage regulator, a charging resistor, a transformer, a switch, and a non-inductive load resistor; wherein, the output terminal of the voltage regulator is coupled to the charging resistor, and the end of the charging resistor away from the voltage regulator is coupled to the transformer via a coaxial cable; the end of the transformer away from the charging resistor is coupled to the non-inductive resistor. The steps for forming the matrix pulse are as follows: Primary energy storage: Another input current is first stepped down by the voltage regulator and then charged to the coaxial cable through the charging resistor to store it as a uniform energy storage electric field; Secondary boost and pulse rectification: This causes the switch to close, triggering the coaxial cable to discharge and generate a pulse. The pulse is boosted by the transformer and then used with a non-inductive load to suppress oscillation and output a uniform matrix pulse.

6. The pulse superimposed DC-excited rare gas glow discharge device according to claim 1, characterized in that, The integrated module comprises a DC channel circuit and a pulse channel circuit. The DC channel circuit is used to apply the high voltage current to the first electrode and the second electrode; The pulse channel circuit is used to couple the rectangular pulse to the first motor and the second motor to collaboratively form the composite excitation electric field.

7. The pulse superimposed DC-excited rare gas glow discharge device according to claim 6, characterized in that, The DC channel circuit consists of a current-limiting inductor and a current-limiting resistor coupled in sequence. The high-voltage current passes through the current-limiting resistor and the current-limiting inductor in sequence so that the current applied to the first electrode and the second electrode is within 2-10mA.

8. The pulse superimposed DC-excited rare gas glow discharge device according to claim 6, characterized in that, The pulse channel circuit includes an isolation bridge; The pulse is sequentially coupled to the first electrode and the second electrode through the isolation bridge.

9. A pulse-superimposed DC-excited rare gas glow discharge device according to any one of claims 1-8, characterized in that, The first electrode is a needle electrode, and the second electrode is a plate electrode adapted to the needle electrode.

10. A pulsed superimposed DC-excited rare gas glow discharge device according to claim 9, characterized in that, The needle electrode is made of tungsten-copper alloy, and the surface of the plate electrode is plated with a nickel metal layer.

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