CN108093551B - Composite power supply device for exciting and generating uniform discharge high-activity plasma - Google Patents

Abstract

The invention discloses a composite power supply device for exciting and generating uniform discharge high-activity plasma, comprising a high-voltage nanosecond pulse power supply, a low-frequency alternating current power supply, a high-pass filter, a low-pass filter and a load; the output of the high-voltage nanosecond pulse power supply Connect to one port of the high-pass filter, and the other port of the high-pass filter is connected to both ends of the load; the output of the low-frequency AC power supply is connected to one port of the low-pass filter, and the other port of the low-pass filter is connected to both ends of the load . The composite power supply device of the present invention superimposes the outputs of the high-voltage nanosecond pulse power supply and the low-voltage low-frequency AC power supply, and when applied to the DBD electrode, it is easy to generate uniform discharge and highly active plasma, and can prevent the power supply device from being damaged.

Description

A composite power supply device for excitation and generation of uniform discharge highly active plasma

technical field

The invention belongs to the technical field of discharge plasma, and particularly relates to a composite power supply device for exciting and generating uniform discharge high-activity plasma.

Background technique

Low-temperature plasma has broad application prospects in the fields of energy chemical industry, material surface modification, and medical sterilization and disinfection. Dielectric Barrier Discharge (DBD) at atmospheric pressure is one of the important methods to generate low-temperature plasma, but how to generate large-area and uniform DBD has always been a difficulty in experimental research and industrial applications. In addition, the high activity of plasma is also the focus of plasma application, and how to effectively couple energy into chemical reactions is an important problem that needs to be solved urgently.

The traditional DBD drive power adopts AC power with frequency of 10 ² ~ 10 ⁵ Hz and amplitude of about 10kV. AC power consumes a large amount of power and is not conducive to the formation of uniform DBD plasma in the air. In addition, the traditional low-frequency power supply is easy to generate excited state molecules, but it is difficult to generate uniform discharge. In recent years, with the development of pulse power technology, the high-voltage nanosecond pulse power supply as a DBD driving power supply is easy to produce uniform discharge and has low power consumption, which has attracted extensive attention from researchers at home and abroad. The problem in the prior art is that although the instantaneous power of the nanosecond pulse power supply is high, its energy is used for gas ionization, not the excited state molecules such as vibrational and rotational states required for chemical reactions. While traditional low-frequency power sources are easy to generate excited molecules, it is difficult to generate uniform discharge.

Chinese Patent Application Announcement No. CN103368445B, discloses a "DC plus pulsed metal surface treatment power supply circuit", designed a processing power supply form with adjustable DC superimposed adjustable pulse width and amplitude waveform. Chinese Patent Application Publication No. CN106900135A, which discloses "a nanosecond pulse superimposed DC power supply device for plasma ignition", builds a high-energy nanosecond pulse superimposed high voltage DC power supply device for plasma ignition, and adopts Multi-needle array-plate electrode structure.

The above designs all use a large number of power electronic devices, and the nanosecond pulse discharge will cause large electromagnetic interference to the power electronic devices, affect the stability of the power electronic devices, and destroy the power supply device. In addition, because most of the applied DC voltage acts on the medium, rather than in the discharge gap, the coupling efficiency of the DC electric field decreases, and excited molecules cannot be effectively generated, which cannot be used for dielectric barrier discharge.

In conclusion, there is an urgent need for a driving power device that is easy to generate uniform discharge.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a composite power supply device for exciting and generating uniform discharge highly active plasma, so as to solve the above-mentioned existing technical problems. The composite power supply device of the present invention superimposes the outputs of the high-voltage nanosecond pulse power supply and the low-voltage low-frequency AC power supply, and is easy to generate uniform discharge high-activity plasma when applied to the DBD electrode.

In order to achieve the above object, the present invention adopts the following technical solutions:

A composite power supply device for exciting and generating uniform discharge highly active plasma, comprising a high-voltage nanosecond pulse power supply, a low-frequency AC power supply, a high-pass filter, a low-pass filter and a load; the output of the high-voltage nanosecond pulse power supply and the high-pass filter One port of the high-pass filter is connected to both ends of the load; the output of the low-frequency AC power supply is connected to one port of the low-pass filter, and the other port of the low-pass filter is connected to both ends of the load.

Further, it also includes a delay trigger; the low-frequency AC power supply is provided with a trigger output end, the high-voltage nanosecond pulse power supply is provided with a trigger input end, and the trigger output end of the low-frequency AC power supply is connected to the input end of the delay trigger, and the delay triggers The output terminal of the device is connected to the trigger input terminal of the high-voltage nanosecond pulse power supply.

Further, the delay of the delay trigger is set to 0.

Further, the high-pass filter is a Butterworth type and adopts an inductance-capacitor structure; the low-pass filter is a Butterworth type and adopts an inductance-capacitor structure.

Further, the low-pass filter adopts a third-order Butterworth structure, including capacitor C ₂ and inductors L ₁ and L ₃ ; the high-voltage end of the low-frequency AC power supply is connected to one end of the inductor _{L 3 ,} and the other end of the inductor L _One end of the inductance L1 is connected, the other end of the inductance L1 is connected to _one end of the load, the other end of the load is connected to the ground end of the low-frequency AC power supply, and one end of the capacitor _C2 is connected to _{one of} the inductance L1 and the inductance L3. In the circuit between, the other end of capacitor _C2 is grounded.

Further, the cut-off frequency of the low-pass filter is 1MHz, and the characteristic impedance is 2000Ω; L ₁ and L ₃ are both wire-wound inductors, and the inductance values are both 318 μH, and C ₂ is a ceramic capacitor with a capacitance value of 160 pF.

Further, the high-pass filter adopts a third-order Butterworth structure, including capacitors C ₄ , C ₆ and inductor L ₅ ; the high-voltage end of the high-voltage nanosecond pulse power supply is connected to one end of the capacitor C ₄ , and the other end of the capacitor C ₄ It is connected with one end of the capacitor _C6 , the other end of the capacitor _C6 is connected with one end of the load, the other end of the load is connected with the ground end of the high _- voltage nanosecond pulse power supply, and one end of the inductor L5 is connected with the capacitor _C4 and the capacitor _The circuit between _C6 , the other end of inductor L5 is grounded.

Further, the cut-off frequency of the high-pass filter is 100kHz, and the characteristic impedance is 2000Ω; the capacitors _C4 and _C6 are both ceramic capacitors with a capacitance value of _800pF , and L5 is a winding inductance with an inductance value of 1.59mH.

Further, the load is a dielectric barrier discharge unit with a parallel plate electrode structure, the electrodes are made of brass, and the barrier medium is aluminum nitride (AlN) ceramics or anodized aluminum oxide (AAO).

Further, the frequency of the low-frequency AC power supply is 50Hz, and the amplitude range is 0-1kV; the frequency of the high-voltage nanosecond pulse power supply is 100Hz, the full width at half maximum is 20ns, and the amplitude range is 0-10kV.

Compared with the prior art, the present invention has the following beneficial effects:

The output of the high-voltage nanosecond pulse power supply of the present invention is applied to the load after passing through a high-pass filter, and the output of the low-frequency AC power supply is applied to the load after passing through a low-pass filter, so as to realize the superposition of the high-voltage nanosecond pulse and the AC voltage; Second pulse power supply, easy to generate uniform discharge plasma, using low-voltage AC power supply, can form more highly active excited state molecules, high density, strong activity, and reduce the power consumption of the system. The high-pass filter of the invention can ensure that the output of the high-voltage nanosecond pulse power supply is applied to the load with less loss, and at the same time can prevent the output of the low-frequency AC power supply from causing damage to the high-voltage nanosecond pulse power supply; the low-pass filter can ensure that the low-frequency AC power supply is damaged. The output of the voltage is applied to the load with a small loss, and at the same time, the output of the high-voltage nanosecond pulse can be prevented from causing damage to the low-frequency AC power supply. The load of the present invention is a dielectric barrier discharge cell or a non-barrier dielectric discharge cell.

Further, the present invention can realize the controllability of the output phase of the nanosecond pulse through the delay trigger. The trigger output end of the low-frequency AC power supply is connected to the input end of the delay trigger, and the output end of the delay trigger is connected to the trigger input end of the high-voltage nanosecond pulse power supply. When the sinusoidal voltage generated by the low-frequency AC power supply crosses zero, the trigger signal is output to the delay trigger, and the delay trigger generates a trigger signal after a preset delay to trigger the high-voltage nanosecond pulse power supply to generate pulse output. The nanosecond pulse source can achieve single trigger or sequence trigger. When the high-voltage nanosecond pulse and the low-frequency AC voltage are superimposed, the generation phase of the high-voltage nanosecond pulse is controllable. After the nanosecond pulse acts, it is easy to generate a regular uniform discharge, which is equivalent to controlling the phase of the uniform discharge at the same time.

Further, both the high-pass filter and the low-pass filter are of Butterworth type, which have the characteristics of flat passband attenuation and easy design. Energy loss due to structure.

Further, the cut-off frequency of the low-pass filter is designed to only allow the low-frequency AC voltage to pass, while blocking the high-voltage nanosecond pulse from passing, ensuring that the output of the low-frequency AC voltage is applied to the load with less loss, while preventing the high-voltage nanosecond pulse from passing through. The output can cause damage to low frequency AC power.

Further, the cut-off frequency of the high-pass filter is designed to only allow high-voltage nanosecond pulses to pass through, while blocking low-frequency AC voltages from passing through, ensuring that the output of the high-voltage nanosecond pulse power supply is applied to the load with less loss, while preventing low-frequency AC voltages from passing through. The output of the power supply causes damage to the high-voltage nanosecond pulse power supply.

Further, the load is a dielectric barrier discharge unit with a parallel plate electrode structure, the electrode is made of brass, the barrier medium can be replaced as needed, and the discharge gap distance is adjustable.

Description of drawings

1 is a schematic structural diagram of a composite power supply device for exciting and generating uniform discharge highly active plasma according to the present invention;

Fig. 2 is the circuit schematic diagram of the low-pass filter in Fig. 1;

3 is a schematic circuit diagram of the high-pass filter in FIG. 1;

FIG. 4 is a structural diagram of the dielectric barrier discharge cell in FIG. 1 .

In FIG. 1 , a high-voltage nanosecond pulse power supply 10 ; a low-frequency AC power supply 20 ; a delay trigger 30 ; a high-pass filter 40 ; a low-pass filter 50 ;

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Please refer to FIG. 1 to FIG. 4 , a composite power supply device for exciting and generating uniform discharge high-activity plasma of the present invention includes a high-voltage nanosecond pulse power supply 10, a low-frequency AC power supply 20, a delay trigger 30, a high-pass Filter 40 , low pass filter 50 and load 60 .

The output of the high-voltage nanosecond pulse power supply 10 is connected to one port of the high-pass filter 40 , and the other port of the high-pass filter 40 is connected to both ends of the load 60 . The output of the low-frequency AC power source 20 is connected to one port of the low-pass filter 50 , and the other port of the low-pass filter 50 is connected to both ends of the load 60 .

The trigger output end of the low frequency AC power supply 20 is connected to the input end of the delay trigger 30 , and the output end of the delay trigger 30 is connected to the trigger input end of the high voltage nanosecond pulse power supply 10 .

The delay of the delay trigger 30 is set to 0, that is, the high-frequency nanosecond pulse power supply 10 is triggered to generate nanosecond pulses at the moment when the AC voltage crosses zero. The frequency of the low-frequency AC power source 20 is 50Hz, and the amplitude is adjustable from 0 to 1kV; the frequency of the high-voltage nanosecond pulse power source 10 is 100Hz; the half-width of the high-voltage nanosecond pulse is 20ns, and the amplitude is adjustable from 0 to 10kV.

The low-pass filter 50 adopts a third-order Butterworth-type structure, and its circuit diagram is shown in FIG. 2 . The low-pass filter 50 includes an inductor L ₁ , an inductor L ₃ and a capacitor C ₂ . One end of the inductor L ₁ is connected to one end of the load 60 , the other end is connected to one end of the inductor L ₃ and one end of the capacitor C ₂ , and the other end of the inductor L ₃ is connected to the low-frequency AC power supply The high voltage end of ₂₀ , the other end of the capacitor C2 is connected to the ground end of the low frequency AC power source 20 and the other end of the load 60 and is grounded. The parameter values of each element of the normalized Butterworth-type low-pass filter can be calculated by the formula:

and

to calculate. Among them, k=1,2,...,n, n is the filter order, C _k is the capacitance value of the k-th order capacitor, and L _k is the inductance value of the k-th order inductance. After obtaining the parameter values of each element of the normalized low-pass filter, the required filter can be obtained by performing cutoff frequency transformation and characteristic impedance transformation. The cutoff frequency of the low-pass filter 50 is designed to be 1 MHz, and the characteristic impedance is 2000Ω. Among them, L ₁ and L ₃ are both wire wound inductors with an inductance value of 318μH, and C ₂ is a ceramic capacitor with a capacitance value of 160pF. By arranging the above-mentioned low-pass filter 50, the output of the high-voltage nanosecond pulse power supply 10 can be prevented from causing damage to the low-frequency AC power supply 20.

The high-pass filter 40 adopts a third-order Butterworth-type structure, and its circuit diagram is shown in FIG. 3 . The high-pass filter 40 includes a capacitor C ₄ , a capacitor C ₆ and an inductor L ₅ , one end of the capacitor C ₆ is connected to one end of the load 60 , the other end is connected to one end of the capacitor C ₄ and one end of the inductor L ₅ , and the other end of the capacitor C ₄ is connected to the high-voltage nanosecond pulse power supply The high-voltage end of ₁₀ , the other end of the inductor L5 is connected to the ground end of the high-voltage nanosecond pulse power supply 10 and the other end of the load 60; the other end of the load 60 is grounded to GND ₁ . The parameters of each element can be obtained by first calculating the parameters of the normalized Butterworth-type low-pass filter, then replacing the capacitor and inductance elements and calculating the reciprocal of the original normalized value, and finally performing the cut-off frequency transformation and characteristic impedance transformation. The cutoff frequency of the high-pass filter 40 is designed to be 100 kHz, and the characteristic impedance is 2000 Ω. Among them, capacitors _C4 and _C6 are ceramic capacitors with a capacitance value of _800pF , and L5 is a wire wound inductance with an inductance value of 1.59mH. By setting the above-mentioned high-pass filter 40 , the output of the low-frequency AC power source 20 can be prevented from causing damage to the high-voltage nanosecond pulse power source 10 .

The load 60 is a dielectric barrier discharge unit with a parallel plate electrode structure, the structure of which is shown in FIG. 4 . The electrode 1 is made of brass, and the blocking medium 2 is aluminum nitride (AlN) ceramic or anodized aluminum oxide (AAO). When AlN and AAO are used as blocking medium, it is more conducive to the generation of uniform discharge.

The output of the high-voltage nanosecond pulse power supply of the present invention is applied to the load after passing through a high-pass filter, and the output of the low-frequency AC power supply is applied to the load after passing through a low-pass filter, so as to realize the superposition of the high-voltage nanosecond pulse and the AC voltage; Second pulse power supply, easy to generate uniform discharge plasma, using low-voltage AC power supply, can form more highly active excited state molecules, high density, strong activity, and reduce the power consumption of the system. The high-pass filter of the invention can ensure that the output of the high-voltage nanosecond pulse power supply is applied to the load with less loss, and at the same time can prevent the output of the low-frequency AC power supply from causing damage to the high-voltage nanosecond pulse power supply; the low-pass filter can ensure that the low-frequency AC power supply is damaged. The output of the voltage is applied to the load with a small loss, and at the same time, the output of the high-voltage nanosecond pulse can be prevented from causing damage to the low-frequency AC power supply. The load of the present invention is a dielectric barrier discharge cell or a non-barrier dielectric discharge cell.

The invention can realize the controllability of the output phase of the nanosecond pulse through the delay trigger. The trigger output end of the low-frequency AC power supply is connected to the input end of the delay trigger, and the output end of the delay trigger is connected to the trigger input end of the high-voltage nanosecond pulse power supply. When the sinusoidal voltage generated by the low-frequency AC power supply crosses zero, the trigger signal is output to the delay trigger, and the delay trigger generates a trigger signal after a preset delay to trigger the high-voltage nanosecond pulse power supply to generate pulse output. The nanosecond pulse source can achieve single trigger or sequence trigger. When the high-voltage nanosecond pulse and the low-frequency AC voltage are superimposed, the generation phase of the high-voltage nanosecond pulse is controllable. After the nanosecond pulse acts, it is easy to generate a regular uniform discharge, which is equivalent to controlling the phase of the uniform discharge at the same time.

Claims (1)

1. a composite power supply device for exciting and producing uniform discharge highly active plasma, characterized in that it comprises a high-voltage nanosecond pulse power supply (10), a low-frequency alternating current power supply (20), a high-pass filter (40), a low-pass filter device (50) and load (60); The output of the high-voltage nanosecond pulse power supply (10) is connected to one port of the high-pass filter (40), and the other port of the high-pass filter (40) is connected to both ends of the load (60); the output of the low-frequency AC power supply (20) is connected to the One port of the low-pass filter (50) is connected, and the other port of the low-pass filter (50) is connected to both ends of the load (60); Also includes a delay trigger (30); The low-frequency AC power supply (20) is provided with a trigger output terminal, the high-voltage nanosecond pulse power supply (10) is provided with a trigger input terminal, and the trigger output terminal of the low-frequency AC power supply (20) is connected to the input terminal of the delay trigger (30), and the delay The output end of the time trigger (30) is connected to the trigger input end of the high-voltage nanosecond pulse power supply (10); The delay of the delay trigger (30) is set to 0; The high-pass filter (40) is a Butterworth structure and adopts an inductance-capacitor structure; the low-pass filter (50) is a Butterworth structure and adopts an inductance-capacitance structure; The low-pass filter (50) includes _a capacitor _C2 and inductors L1 and L3 _; The high-voltage end of the low-frequency AC power supply (20) is connected to one end of the inductor L3, the other end _of the inductor L3 is connected to _one end _of the inductor L1, the other end of the inductor L1 is connected to _one end of the load (60), and the load The other end of (60) is connected with the grounding end of the low-frequency alternating current power supply ( ₂₀ ), _one end of the capacitor C2 is connected to the circuit between the inductor L1 and the inductor L3, and the other end _of the capacitor _C2 is grounded; The high-pass filter (40) includes capacitors C ₄ , C ₆ and inductor L ₅ ; The high-voltage end of the high-voltage nanosecond pulse power supply (10) is connected with one end of the capacitor _C4 , the other end of the capacitor _C4 is connected with one end of the capacitor _C6 , and the other end of the capacitor _C6 is connected with one end of the load (60) , the other end of the load (60) is connected to the ground terminal of the high _- voltage nanosecond pulse power supply ( ₁₀ ), one end of the inductor L5 is connected to the circuit between the capacitor _C4 and the capacitor _C6 , and the other end of the inductor L5 is grounded; The load (60) is a dielectric barrier discharge unit with a parallel plate electrode structure, the electrode is made of brass, and the barrier medium is aluminum nitride ceramic or anodized aluminum; The cut-off frequency of the low-pass filter (50) is 1MHz, and the characteristic impedance is 2000Ω; L1 and L3 are both wire _- wound inductors, and the inductance value is _318μH ; _C2 is a ceramic dielectric capacitor, and the capacitance value is 160pF; The cut-off frequency of the high-pass filter (40) is 100kHz, and the characteristic impedance is 2000Ω; the capacitors _C4 and _C6 are both ceramic capacitors with a capacitance value of _800pF , and L5 is a winding inductance with an inductance value of 1.59mH; The frequency of the low-frequency alternating current power supply (20) is 50Hz, and the amplitude range is 0-1kV; the frequency of the high-voltage nanosecond pulse power supply (10) is 100Hz, the half width is 20ns, and the amplitude range is 0-10kV.

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