Synchronous magnetic drive intermediate frequency gliding arc plasma generating device

Abstract

The invention belongs to the technical field of plasmas, and particularly relates to a synchronous magnetic drive medium-frequency gliding arc plasma generating device. A 20kHz / 15kV sine alternating current signal is used as an excitation source to induce discharge to form a stable arc. A magnetic field parallel to the axis is generated through the axial excitation coil, and meanwhile a magnetic field rotating around the axis is generated through the windings arranged circumferentially. Through a synchronous control circuit, a sine alternating current signal is used as a reference source, and based on a complementary PWM signal, a 48V direct current input half-bridge circuit and a synchronous signal, an MOSFET is driven, so that magnetic field phase synchronization is realized, and an electric arc is driven to form an anticlockwise spiral rising sliding track. Medium-frequency excitation is innovatively adopted to reduce energy consumption and electrode loss, the double-magnetic-field design ensures that the electric arc can stretch and slide at a low gas flow rate, and the plasma reaction rate is increased.

Description

Technical Field

[0001] The invention belongs to the field of plasma technology, and in particular relates to a synchronous magnetic-driven medium-frequency sliding arc plasma generating device. Background Art

[0002] Plasma is the fourth state of matter, an electrically neutral conductive fluid composed of ionized gases containing free electrons, ions, and neutral particles. It is widely present in the universe (e.g., stars and lightning) and can also be generated through artificial discharges such as arc discharge and radio frequency discharge. Plasma processing is an advanced materials processing technology with advantages such as high raw material utilization, low energy consumption, zero pollution, and high-value by-products. This technology can achieve chemical reactions that are difficult to carry out under conventional conditions, offering significant advantages in clean production and energy utilization.

[0003] Gliding arc plasma technology originated from arc discharge research in the early 20th century. After nearly a century of development, it has evolved from a fundamental physical phenomenon into a valuable technology for energy and environmental applications. In the 1980s and 1990s, researchers such as Fridman, Kennedy, and Czernichowski systematically investigated its physical properties and potential applications, developing a two-electrode reactor. Since the beginning of the 21st century, the technology has rapidly advanced, with the emergence of improved reactors such as rotating and liquid-medium sliding arcs. Its applications have expanded to greenhouse gas reforming (e.g., CH₄ and CO₂ to H₂ and CO), VOC degradation, wastewater treatment, and plasma nitrogen fixation. A gliding arc plasma device is a highly efficient device that generates a nonequilibrium plasma by generating a sliding, extendable arc between high-voltage electrodes. Typical gliding arc devices can be categorized as traditional blade-type, rotating, gas-driven, and coaxial. Despite challenges such as electrode erosion, discharge stability, and gas flow rate requirements, its flexible structure and high energy efficiency make it a key technology in the green energy and chemical industries. Future improvements in performance are possible through material optimization and intelligent control.

[0004] KALRA CS, GUTSOL AF, FRIDMAN AA. (Gliding arc discharge as a source of intermediate plasma for methane partial oxidation, 2005, 33: 32-41.) introduces a 2D planar blade-type reactor that uses two perpendicular flat plates as planar two-dimensional electrodes. The distance between the two electrodes increases axially. Driven by a high-speed airflow at the bottom of the reactor, the arc slides along the electrodes in the airflow. In this device, the blade-type sliding arc discharge reaction requires a high-speed airflow, which increases system cost. The plasma area it produces is limited, and a large amount of feed gas does not pass through the plasma area. At the same time, the high gas flow rate shortens the residence time of the feed gas in the reactor, resulting in low efficiency of the blade-type sliding arc discharge.

[0005] A Chinese patent document with publication number CN216217684U discloses a sliding arc plasma device, in which the inner and outer electrodes of the device are connected to a DC power supply, and an airflow is used to drive the arc to rotate and discharge. The rotating airflow increases the plasma reaction area, thereby increasing the output of the target product. However, the device still has several key deficiencies. First, the gas consumption is too large, and maintaining a stable discharge usually requires a high-flow gas supply, which significantly increases the operating cost. Secondly, the system is extremely sensitive to airflow parameters, and fluctuations in the gas flow rate can cause drastic changes in the arc length. Finally, when using a DC power supply, gas breakdown requires a high breakdown voltage, which greatly increases the complexity and cost of the system.

[0006] GANGOLI SP, GUTSOL AF, FRIDMAN AA. (Anon-equilibrium plasma source: magnetically stabilized gliding arc discharge, 2010, 19(6):065004.) introduces a magnetically driven gliding arc plasma reactor. The reactor adopts a coaxial structure design and consists of a conical inner electrode (high voltage electrode), a cylindrical outer electrode (ground electrode), and an arc-starting electrode. A DC power supply is connected between the inner and outer electrodes, and a ceramic annular permanent magnet is used to provide an external magnetic field. In this device, the high breakdown voltage problem that exists when using a DC power supply has not been solved. Continuous current will also cause the electrode surface to be subjected to high current density for a long time, especially at the arc attachment point. Local high temperature will accelerate the melting of the electrode material. In addition, the external magnetic field is provided by a ceramic annular permanent magnet. The ceramic material is hard but brittle, and the magnetic field distribution of the permanent magnet is relatively uneven. At the same time, the reactor still requires a high flow rate of gas to maintain the efficiency and stability of the gliding arc plasma reaction process.

[0007] In summary, the gliding arc plasma reactor has undergone a development process from a planar plasma region to a cylindrical plasma region, and from gas drive to magnetic field drive. However, it still faces several key challenges: First, the high gas flow rate requirement has always been the main bottleneck limiting the performance of the gliding arc reactor. Second, under the DC power supply drive mode, the high transient voltage required for gas dielectric breakdown significantly increases the technical requirements for the transformer and power supply system. In addition, when using a low-frequency AC signal to excite the electromagnetic coil, a high magnetic field strength must still be maintained to ensure arc stability, which further increases the difficulty of transformer design. To address the above issues, it is necessary to develop a new gliding arc device that can reduce gas flow rate dependence, optimize the high-voltage power supply configuration, and improve plasma conversion efficiency.

[0008] In view of this, the inventors hope to design a synchronous magnetic drive medium frequency sliding arc plasma generating device, which has the advantages of high efficiency and simple operation. Summary of the Invention

[0009] The purpose of the present invention is to overcome the above-mentioned problems existing in traditional technologies and to provide a synchronous magnetic-driven medium-frequency sliding arc plasma generator. By adopting a medium-frequency AC power supply design, the electrode ablation effect and the gas breakdown voltage requirement are significantly reduced. A 20kHz medium-frequency square wave power supply is used to excite the excitation coil and winding, introducing a dual magnetic field to drive the arc sliding and generate a uniformly distributed magnetic field. The design of generating a magnetic field by medium-frequency excitation not only improves the stability of the sliding arc discharge, but also increases the efficiency of magnetic field energy utilization, thereby reducing the required magnetic field strength while maintaining the same discharge effect, effectively optimizing power supply costs. In particular, even under low gas flow conditions, the dual magnetic field can achieve effective arc stretching and directional sliding, avoiding local arc stagnation and increasing the plasma reaction rate.

[0010] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0011] The present invention provides a synchronous magnetic drive medium frequency sliding arc plasma generating device, comprising a first component, a second component, a third component and a fourth component, wherein the first component is nested inside the second component, the second component is nested inside the third component, and the third component is arranged at the bottom of the fourth component;

[0012] The first component includes a metal chassis, an air inlet, an inner cylinder and an inner electrode; the outer side of the metal chassis is connected to the inner cylinder by a threaded connection, the inner electrode is installed at the center of the metal bottom plate 1, and the metal bottom plate 1 is provided with a plurality of air inlets around the inner electrode;

[0013] The second component includes an upper structure, a lower structure, a grounding port, a vent hole, and a power hole; the upper structure is connected to the lower structure by a threaded connection, the side surface of the cylinder wall of the lower structure is provided with a grounding port, and the interior of the lower structure is provided with a vent hole and a power hole;

[0014] The third component includes an outer cylinder, a winding mounting hole, a winding, an excitation coil, and an isolation cylinder; the excitation coil is wound on the outer surface of the cylinder portion of the outer cylinder, the isolation cylinder is mounted at the center of the outer cylinder by a threaded connection, and a plurality of winding mounting holes are opened on the cylinder wall of the outer cylinder around the isolation cylinder, and the windings are mounted in the winding mounting holes;

[0015] The fourth component includes an insulating shell, an air pipe, a high-voltage wire, a high-voltage electrode and a high-voltage electrode connection hole. The bottom of the insulating shell is sleeved on the outside of the third component. The air pipe can be connected to the air vent of the second component. The high-voltage wire can be connected to the power hole of the second component. The front end of the high-voltage wire is connected to the high-voltage electrode, and the high-voltage electrode connection hole extends to the hollow interior of the inner electrode.

[0016] Furthermore, the metal chassis is a disc made of stainless steel, and a first external thread is provided on the outer side of the cylinder wall of the metal chassis; the inner cylinder is a hollow cylinder made of alumina ceramic, and a first internal thread groove is provided on the inner side of the cylinder wall of the inner cylinder to match the first external thread; the air inlet is a cylindrical hole; the inner electrode is a hollow cone with a top end, and a material is stainless steel.

[0017] Furthermore, a first component is embedded in the bottom of the upper structure and is embedded in the third component; the upper structure is made of metal stainless steel, and the lower inner wall of the upper structure is provided with a second internal thread; the lower structure is cylindrical and made of metal stainless steel, and the upper outer wall of the lower structure is provided with a second external thread that cooperates with the second internal thread.

[0018] Furthermore, the outer cylinder is a hollow cylinder made of metal stainless steel, and the inner side of the cylinder wall of the outer cylinder is provided with a third internal thread; the isolation cylinder is a hollow cylinder made of alumina ceramic, and the outer surface of its cylinder wall is provided with a third external thread that cooperates with the third internal thread.

[0019] Furthermore, the upper structure is embedded in the interior of the isolation cylinder, the third component is installed in the bottom of the insulating shell, and the top of the insulating shell is tightly nested with the upper structure.

[0020] Furthermore, the excitation coil is wound with 30 turns of 1mm diameter enameled wire, with a coil height of 58mm and an operating voltage of 310V, generating an axial magnetic field of 0.04 to 0.06T.

[0021] Furthermore, the direction of the magnetic field generated by the winding rotates approximately around the axis, and the windings are connected to each other in series using metal copper wire; each winding is wound with 8 turns of 1mm diameter enameled wire, the coil height is 58mm, the operating voltage is 336V, and the magnetic field generated ranges from 0.04 to 0.06T.

[0022] Furthermore, synchronous control is used to achieve magnetic field generation. Both independent half-bridge circuits use 48V DC input, and two groups of MOSFETs are alternately turned on at a frequency of 20kHz. The two groups of MOSFETs are marked as Q1, Q2 and Q3, Q4, respectively driving the axial excitation coil on the surface of the outer cylinder and the internal series winding to generate a magnetic field; the system uses 15kV / 20kHz sinusoidal AC as the reference source, and generates two groups of complementary PWM signals (15V / 0V) through the synchronous driver to accurately control the timing of the four MOSFETs to ensure phase synchronization of the magnetic field.

[0023] The working principle of the present invention is:

[0024] Gliding arc plasma, a unique type of plasma, combines the characteristics of thermal and non-thermal plasmas and is therefore often referred to as "warm plasma." This plasma not only exhibits a high degree of nonequilibrium, providing an ideal environment for chemical reactions, but also possesses high electron temperatures and densities, enabling high-energy-density applications. The generation of gliding arc plasma involves a complex electrodynamic phenomenon.

[0025] The present invention uses an external magnetic field to drive the arc sliding. The external magnetic field is provided by an excitation coil and 10 windings arranged along a circumference and connected in series. A sinusoidal AC power supply with a frequency of 20kHz and a peak voltage of 15kV is used. The high-voltage end is connected to the high-voltage electrode via a high-voltage line, and the other end is connected to the ground port on the device housing. The inner electrode is connected to the high-voltage electrode via the high-voltage electrode connection hole and connected to the sinusoidal AC power supply. After the gas medium is introduced, the strong electric field applied between the electrodes exceeds the critical breakdown threshold of the gas medium, and electrical breakdown occurs. Discharge first occurs at the minimum electrode gap of 7.5mm, forming an arc.

[0026] Design half-bridge circuit 1: Using a 48V DC input, alternately conduct the two power MOSFETs (Q1 and Q2) at a switching frequency of 20kHz. Based on transformer T1's turns ratio (1:6.5), the output voltage is a 310V square wave signal. The voltage divider capacitors (C1 and C2) are 22μF / 50V. Connect the excitation coil to the load side of the circuit.

[0027] Design half-bridge circuit 2: Using a 48V DC input, alternately conduct the two power MOSFETs (Q3 and Q4) at a switching frequency of 20kHz. Based on transformer T2's turns ratio (1:7), the output voltage is a 336V square wave signal 2. The voltage divider capacitors (C3 and C4) are 22μF / 50V. Connect the series winding to the load side of this circuit.

[0028] The system uses a 20kHz, 15kV peak-to-peak sinusoidal AC power source as a reference signal source, outputting two 5V synchronous clock signals. Each signal is fed into a separate synchronous driver. After processing, each signal generates two complementary drive signals (high-side 15V / low-side 0V) to control the alternating conduction of the four MOSFET devices in the two independent half-bridge topologies at a 20kHz frequency.

[0029] During the positive half-cycle of the reference AC power supply, the current in the reaction zone flows from the inner electrode to the inner cylinder. The gate drive signal for MOSFET (Q1) is 0V, and the gate drive signal for MOSFET (Q2) is 15V, meaning Q1 is off and Q2 is on. At this time, square wave signal 1 excites the excitation coil, generating a magnetic field directed downward along the device axis. Under the influence of this magnetic field, the charged particles within the reaction zone are affected by the Lorentz force, causing the arc trajectory to rotate counterclockwise along the inner electrode within the plane. Simultaneously, the gate drive signal for MOSFET (Q4) is 0V, and the gate drive signal for MOSFET (Q3) is 15V. This means Q4 is off and Q3 is on. At this time, square wave signal 2 excites the series winding, coupling to generate a magnetic field that rotates approximately counterclockwise around the device axis. This results in the arc being subjected to a Lorentz force directed upward along the axis. Under the influence of these two magnetic fields, the arc trajectory spirals counterclockwise along the inner electrode.

[0030] Similarly, when the reference AC power supply is in the negative half-cycle, the output signal direction is reversed, and the current in the reaction zone flows from the inner cylinder to the inner electrode. Q1 is on, Q2 is off; Q4 is on, and Q3 is off. Square wave signals 1 and 2 have reversed output signal directions. At this point, the excitation coil generates a magnetic field directed upward along the device's axis. Under the influence of this magnetic field, the charged particles within the reaction zone, driven by the Lorentz force, rotate the arc trajectory counterclockwise along the inner electrode within the plane. The magnetic field coupling between the windings generates a magnetic field that rotates approximately clockwise around the device's axis, causing the arc to still be subject to the Lorentz force directed upward along the axis.

[0031] In summary, by controlling the synchronization of the above three AC signals, the arc trajectory always spirals upward from bottom to top and counterclockwise throughout the entire cycle of the AC signal.

[0032] The beneficial effects of the present invention are:

[0033] 1. Compared with existing technologies, the present invention adopts a three-dimensional coaxial structure. The cylindrical plasma reactor structure increases the volume of the plasma discharge space and improves the residence time of the gas in the plasma region, making it easier to obtain a large and uniform plasma. Furthermore, the cylindrical structure of the reactor is also compatible with most industrial systems.

[0034] 2. Compared with the existing technology, the sliding arc plasma generator adopts a 20kHz medium frequency AC power supply to drive the external excitation coil and winding to generate a magnetic field, and controls the synchronization of the power supply used. Under the action of the dual magnetic field, the charged particles in the plasma form a sliding arc plasma with a trajectory from bottom to top and counterclockwise spiral rise. Even under the conditions of relatively low gas flow rates, the present invention can increase the rotation speed of the discharge channel through the magnetic field, and can promote arc stretching and sliding, and avoid the arc stagnation in a local position. The contact area between the raw gas and the plasma is expanded, while ensuring a more uniform distribution of active particles and achieving a higher gas conversion rate. At the same time, when the medium frequency AC signal is used to excite the coil and winding to generate a magnetic field, the stability of the sliding arc and the efficiency of the magnetic field are significantly improved, which can reduce the required magnetic field strength.

[0035] 3. Compared to existing technologies, the present invention utilizes a 20kHz medium-frequency AC power supply. Compared to DC power supplies, medium-frequency power supplies can effectively reduce current erosion of electrodes. The medium-frequency AC power supply utilizes its voltage gradient and residual ionization effect to effectively reduce the breakdown voltage, thereby lowering the system power requirements. Furthermore, the rapid voltage alternation of the medium-frequency signal can cause the arc to immediately reignite before extinguishing, achieving quasi-continuous discharge and avoiding the intermittent extinction problem of low-frequency AC.

[0036] Of course, any product implementing the present invention does not necessarily need to achieve all of the above advantages at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 Schematic diagram of the structure of the first component in the device of the present invention;

[0039] Figure 2 Schematic diagram of the structure of the second component in the device of the present invention;

[0040] Figure 3 Schematic diagram of the structure of the third component in the device of the present invention;

[0041] Figure 4 Schematic diagram of the structure of the reaction unit in the device of the present invention;

[0042] Figure 5 Schematic diagram of the structure of the fourth component in the device of the present invention;

[0043] Figure 6 This is a signal synchronization flow chart of the device of the present invention;

[0044] In the accompanying drawings, the reference numerals of the various components are as follows:

[0045] 1-metal chassis, 2-air inlet, 3-inner cylinder, 4-inner electrode, 5-first component, 6-upper structure, 7-lower structure, 8-grounding port, 9-vent, 10-power hole, 11-second component, 12-outer cylinder, 13-winding mounting hole, 14-winding, 15-excitation coil, 16-isolation cylinder, 17-third component, 18-insulating shell, 19-trachea, 20-high-voltage line, 21-high-voltage electrode, 22-high-voltage electrode connection hole. DETAILED DESCRIPTION

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0047] like Figures 1-6 As shown, this embodiment provides a synchronous magnetic drive medium frequency sliding arc plasma generating device, including a first component 5, a second component 11, a third component 17 and a fourth component. The first component 5 is nested in the second component 11, the second component 11 is nested in the third component 17, and the third component 17 is arranged at the bottom of the fourth component.

[0048] The first component 5 includes a metal chassis 1, an air inlet 2, an inner cylinder 3 and an inner electrode 4; the outer side of the metal chassis 1 is connected to the inner cylinder 3 by a threaded connection, the inner electrode 4 is installed at the center of the metal bottom plate 1, and the metal bottom plate 1 is provided with a plurality of air inlets 2 around the inner electrode 4.

[0049] The second component 11 includes an upper structure 6, a lower structure 7, a grounding port 8, a vent 9, and a power hole 10. The upper structure 6 is connected to the lower structure 7 by a threaded connection. The grounding port 8 is provided on the side of the cylinder wall of the lower structure 7, and the vent 9 and power hole 10 are provided inside the lower structure 7.

[0050] The third component 17 includes an outer cylinder 12, winding mounting holes 13, windings 14, an excitation coil 15, and an isolation tube 16. The excitation coil 15 is wound around the outer surface of the outer cylinder 12. The isolation tube 16 is mounted at the center of the outer cylinder 12 via a threaded connection. A plurality of winding mounting holes 13 are formed in the outer cylinder 12 around the isolation tube 16. The windings 14 are mounted in the winding mounting holes 13.

[0051] The fourth component includes an insulating shell 18, an air pipe 19, a high-voltage wire 20, a high-voltage electrode 21 and a high-voltage electrode connection hole 22. The bottom of the insulating shell 18 is mounted on the outside of the third component 17. The air pipe 19 can be connected to the air vent 9 of the second component 11. The high-voltage wire 20 can be connected to the power hole 10 of the second component 11. The front end of the high-voltage wire 20 is connected to the high-voltage electrode 21, and the high-voltage electrode connection hole 22 extends to the hollow interior of the inner electrode 4.

[0052] The structure of the first component 5 is as follows Figure 1 As shown:

[0053] Among them, the metal chassis 1 is a cylinder made of stainless steel, with a diameter of 29.5 mm and a height of 5 mm. The outer surface is provided with threads, which are connected to the inner cylinder 3 through the threads, and the height of the inner electrode 4 and the metal chassis 1 in the inner cylinder 3 is adjusted through the threads.

[0054] Among them, the air inlet 2 is a cylindrical hole with a diameter of 4 mm and a height of 5 mm; it is arranged along the circumference, with a total of 8, located on the metal bottom plate 1; after the gas is introduced into the device, the gas directly enters the inner cylinder 3.

[0055] The inner cylinder 3 is a hollow cylinder made of alumina ceramic, with threads on its inner surface. This serves as the plasma generation zone. It has an inner diameter of 31 mm, an outer diameter of 35 mm, and a height of 50 mm. It is connected to the metal chassis 1 via threads.

[0056] Among them, the inner electrode 4 is a hollow cone with a top, made of metal stainless steel. The hollow part is connected to the high-voltage electrode 21; it is connected to the metal chassis 1 and is located at the center of the inner cylinder 3. The outer diameter of the lower bottom surface is 16mm, the inner diameter of the lower bottom surface is 7mm, the diameter of the upper bottom surface is 7mm, and the height is 50mm; its top thickness is 5mm.

[0057] The structure of the second component 11 is as follows Figure 2 As shown:

[0058] Among them, the upper structure 6 is a composite geometric body, which includes a top, a middle and a bottom. The material is metal stainless steel. The bottom is a hollow cylinder with an outer diameter of 42mm, an inner diameter of 36mm and a height of 58mm. The lower end of the inner cylinder wall is provided with a thread. The bottom is embedded with the first component 5 of the device and embedded with the third component 17 of the device. The middle part of the upper structure 6 is a thin-walled cylinder with an outer diameter of 24mm, an inner diameter of 20mm and a height of 35mm. The upper end of the inner wall is provided with a thread. The bottom and the middle part are connected by a hollow cone with a gradient cross-section. The outer diameter of the bottom surface of the cone is 24mm and the inner diameter of the upper bottom surface is 24mm. 20mm, lower bottom outer diameter 42mm, lower bottom inner diameter 36mm, height 9mm; the upper structure 6 includes a truncated cone and a thin-walled cylinder extending from it at the top, with an upper bottom outer diameter of 10mm, an upper bottom inner diameter of 7mm, a lower bottom outer diameter of 20mm, a lower bottom inner diameter of 17mm, and a height of 12mm. The thin-walled cylinder extending from the upper bottom is 10mm high, and the top and the middle are connected by a hollow cylinder with an outer diameter of 20mm, an inner diameter of 17mm, and a height of 10mm. The lower end of the outer surface of the hollow cylindrical wall is provided with a thread, which is connected to the middle of the metal shell through the thread.

[0059] Among them, the lower structure 7 is approximately a cylinder with a bottom diameter of 42mm and a height of 36mm. It is made of metal stainless steel and has a thread on the upper end of the outer wall, which is connected to the metal shell upper structure 6; a grounding port 8 is provided on the side of the cylinder wall; and an air pipe through hole 9 and a high-voltage wire through hole 10 are provided inside.

[0060] The diameters of the air pipe through hole 9 and the high-voltage wire through hole 10 are 10 mm.

[0061] The structure of the third component 17 is as follows Figure 3 As shown:

[0062] Among them, the outer cylinder 12 is a hollow cylinder made of metal stainless steel, with an inner diameter of 47mm, an outer diameter of 67mm, and a height of 58mm. The inner surface of the cylinder wall is provided with a thread, the outer surface of the cylinder wall is wound with an excitation coil 15, and a collection of circumferentially arranged windings 14 is provided inside the cylinder wall.

[0063] There are two winding mounting holes 13 arranged circumferentially inside the outer cylinder 12, with 10 holes per circle, for a total of 20 holes, for winding the winding 14. The rectangular holes are 12 mm long, 4 mm wide and 58 mm high.

[0064] Ten windings 14 are wound along winding mounting holes 13. When powered on, the direction of the magnetic field generated by them rotates approximately around the device's axis. Windings 14 are connected in series using copper wire. The enameled wire has a diameter of 1 mm, each winding has 8 turns, and a height of 58 mm. When the series windings are connected to a 336V voltage, the magnetic field generated ranges from 0.04 to 0.06 T.

[0065] The outer surface of the outer cylinder 12 is wound with an excitation coil 15, which generates a magnetic field in the direction of the device axis. The total number of turns of the additional coil is 30. The diameter of the enameled wire is 1mm, the coil height is 58mm, and when connected to a voltage of 310V, the magnetic field generated ranges from 0.04 to 0.06T.

[0066] The isolation tube 16 is a hollow cylinder made of alumina ceramic with an inner diameter of 43 mm, an outer diameter of 47 mm, and a height of 58 mm. The outer surface of the isolation tube 16 is threaded and connected to the outer cylinder 12 via the thread. The metal shell superstructure 6 is embedded in the isolation tube.

[0067] The structure of the fourth component is as follows Figure 5 As shown:

[0068] The insulating housing 18 is a complex hollow geometric structure, consisting of a bottom, a bottom cover, and a top. Made of alumina ceramic, the bottom is a thin-walled cylinder with an outer diameter of 75mm, an inner diameter of 70mm, and a height of 58mm. The third component 17 is located within it. The lower end of the inner wall is threaded. The bottom cover is a short hollow cylinder with an outer diameter of 70mm, an inner diameter of 47mm, and a height of 3.5mm. The outer surface of the cylinder wall is threaded and connected to the bottom via the threads. The bottom and top are connected by a hollow frustum with a tapered cross-section. The upper bottom surface of the frustum has an outer diameter of 30mm, an inner diameter of 25mm, an outer diameter of 75mm, an inner diameter of 70mm, and a height of 20mm. The top of the insulating housing 18 is a hollow cylinder with an outer diameter of 30mm, an inner diameter of 25mm, and a height of 13mm. This part is tightly nested with the superstructure 6.

[0069] The high-voltage electrode 21 is composed of a short cylinder and a long cylinder, and is connected to the high-voltage line 20. The short cylinder has a diameter of 17 mm and a height of 5 mm; the long cylinder has a diameter of 5 mm and a height of 20 mm.

[0070] The high-voltage electrode connection hole 22 is located in the hollow interior of the inner electrode 4 .

[0071] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0072] A specific application of this embodiment is: Figure 4-Figure 6Schematic diagram of a sinusoidal AC power source with a frequency of 20 kHz and a peak voltage of 15 kV. The high-voltage end of the power source is connected to a high-voltage electrode 21 via a high-voltage line 20, and the other end is connected to a ground port 8 on the device's outer casing. The high-voltage electrode 21 is connected to a high-voltage electrode connection hole 22 located within the hollow interior of the inner electrode 4, allowing the inner electrode 4 to receive a sinusoidal AC signal with a frequency of 20 kHz and a peak voltage of 15 kV. A gas pipe 19 is connected to the device through the gas pipe through hole 9. The gas medium is introduced into the device through the gas pipe 19 and enters the inner cylinder 3 through the gas inlet 2, and then into the plasma reaction zone. The gas undergoes electrical breakdown, generating a high-energy electron flow and plasma channel, forming an arc. A dual half-bridge topology is employed, with magnetic field generation achieved through synchronous control. Two independent half-bridge circuits each utilize a 48V DC input, with two sets of MOSFETs (Q1, Q2 and Q3, Q4) alternately conducting at a 20kHz frequency. Transformer T1 (transformation ratio 1:6.5) boosts the voltage to 310V, and transformer T2 (transformation ratio 1:7) boosts the voltage to 336V. Combined with a 22μF / 50V voltage divider capacitor, these drive the axial excitation coil 15 on the outer cylinder surface and the internal series winding 14, respectively, generating a magnetic field parallel to the axis and a magnetic field rotating about the axis. The system uses a 15kV / 20kHz sinusoidal AC reference source, generating two sets of complementary PWM signals (15V / 0V) through a synchronous driver. This precisely controls the timing of the four MOSFETs to ensure magnetic field phase synchronization. Based on the aforementioned operating principle, the combined action of the two magnetic fields ensures that the arc trajectory consistently slides in a counterclockwise spiral from bottom to top along the device axis. This promotes arc stretching and sliding, increasing the plasma reaction rate.

[0073] A dual half-bridge topology is employed, with magnetic field generation achieved through synchronous control. Two independent half-bridge circuits each utilize a 48V DC input, with two sets of MOSFETs (Q1, Q2 and Q3, Q4) alternately conducting at a 20kHz frequency. Transformer T1 (transformation ratio 1:6.5) boosts the voltage to 310V, and transformer T2 (transformation ratio 1:7) boosts the voltage to 336V. Combined with a 22μF / 50V voltage divider capacitor, these drive the axial excitation coil 15 on the outer cylinder surface and the internal series winding 14, respectively, generating a magnetic field parallel to the axis and a magnetic field rotating about the axis. The system uses a 15kV / 20kHz sinusoidal AC reference source, generating two sets of complementary PWM signals (15V / 0V) through a synchronous driver. This precisely controls the timing of the four MOSFETs to ensure magnetic field phase synchronization. Based on the aforementioned operating principle, the combined action of the two magnetic fields ensures that the arc trajectory consistently slides in a counterclockwise spiral from bottom to top along the device axis. This promotes arc stretching and sliding, increasing the plasma reaction rate.

[0074] The insulating housing 18 is tightly connected to the device by nesting its top with the superstructure 6. The third component 17 is located inside the insulating housing 18, isolating the third component 17 from the outside world and insulating the excitation coil 15, winding 14 and outer cylinder 12.

[0075] The present invention uses a 20kHz / 15kV sinusoidal AC signal as the excitation source to induce discharge and form a stable arc. An axial excitation coil generates a magnetic field parallel to the axis, while a circumferentially arranged winding generates a magnetic field rotating about the axis. A synchronous control circuit uses the sinusoidal AC signal as a reference source. Based on complementary PWM signals, a 48V DC input half-bridge circuit is used. The synchronization signal drives the MOSFET, achieving magnetic field phase synchronization and driving the arc to form a sliding trajectory that spirals upward in a counterclockwise direction. The present invention innovatively introduces dual-magnetic field-driven arc sliding discharge technology, utilizing a 20kHz intermediate-frequency square wave power supply to excite the excitation coil and windings, generating a uniformly distributed magnetic field. Compared to traditional low-frequency AC excitation methods, the intermediate-frequency design not only improves the stability of the sliding arc discharge but also enhances the efficiency of magnetic field energy utilization. This reduces the required magnetic field strength while maintaining the same discharge effect, effectively optimizing power supply costs. In particular, even under low gas flow rates, the dual magnetic field enables effective arc stretching and directional sliding, avoiding local arc stagnation and increasing the plasma reaction rate.

[0076] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A synchronous magnetic drive medium frequency sliding arc plasma generating device, characterized in that: The device comprises a first component, a second component, a third component and a fourth component, wherein the first component is nested inside the second component, the second component is nested inside the third component, and the third component is arranged at the bottom of the fourth component; The first component includes a metal chassis, an air inlet, an inner cylinder and an inner electrode; the outer side of the metal chassis is connected to the inner cylinder by a threaded connection, the inner electrode is installed at the center of the metal bottom plate 1, and the metal bottom plate 1 is provided with a plurality of air inlets around the inner electrode; The second component includes an upper structure, a lower structure, a grounding port, a vent hole, and a power hole; the upper structure is connected to the lower structure by a threaded connection, the side surface of the cylinder wall of the lower structure is provided with a grounding port, and the interior of the lower structure is provided with a vent hole and a power hole; The third component includes an outer cylinder, a winding mounting hole, a winding, an excitation coil, and an isolation cylinder; the excitation coil is wound on the outer surface of the cylinder portion of the outer cylinder, the isolation cylinder is mounted at the center of the outer cylinder by a threaded connection, and a plurality of winding mounting holes are opened on the cylinder wall of the outer cylinder around the isolation cylinder, and the windings are mounted in the winding mounting holes; The fourth component includes an insulating shell, an air pipe, a high-voltage wire, a high-voltage electrode and a high-voltage electrode connection hole. The bottom of the insulating shell is sleeved on the outside of the third component. The air pipe can be connected to the air vent of the second component. The high-voltage wire can be connected to the power hole of the second component. The front end of the high-voltage wire is connected to the high-voltage electrode, and the high-voltage electrode connection hole extends to the hollow interior of the inner electrode.

2. The synchronous magnetic drive medium frequency sliding arc plasma generating device according to claim 1, characterized in that: The metal chassis is a circular disc made of stainless steel, and a first external thread is provided on the outer side of the cylinder wall of the metal chassis; the inner cylinder is a hollow cylinder made of alumina ceramic, and a first internal thread groove is provided on the inner side of the cylinder wall of the inner cylinder to match the first external thread; the air inlet is a cylindrical hole; the inner electrode is a hollow cone with a top end, and a material is stainless steel.

3. The synchronous magnetic drive medium frequency sliding arc plasma generating device according to claim 1, characterized in that: The bottom of the upper structure is embedded with a first component and is also embedded in the third component; the upper structure is made of metal stainless steel, and the lower inner wall of the upper structure is provided with a second internal thread; the lower structure is cylindrical and is made of metal stainless steel, and the upper outer wall of the lower structure is provided with a second external thread that cooperates with the second internal thread.

4. The synchronous magnetic drive medium frequency sliding arc plasma generating device according to claim 1, characterized in that: The outer cylinder is a hollow cylinder made of stainless steel, and a third internal thread is provided on the inner side of the cylinder wall of the outer cylinder; the isolation cylinder is a hollow cylinder made of alumina ceramic, and a third external thread is provided on the outer surface of the cylinder wall to match the third internal thread.

5. The synchronous magnetic drive medium frequency sliding arc plasma generating device according to claim 1, characterized in that: The upper structure is embedded in the interior of the isolation cylinder, the third component is installed in the bottom of the insulating shell, and the top of the insulating shell is tightly nested with the upper structure.

6. The synchronous magnetic drive medium frequency sliding arc plasma generating device according to claim 1, characterized in that: The excitation coil is wound with 30 turns of 1mm diameter enameled wire, with a coil height of 58mm and an operating voltage of 310V, generating an axial magnetic field of 0.04-0.06T.

7. The synchronous magnetic drive medium frequency sliding arc plasma generating device according to claim 1, characterized in that: The direction of the magnetic field generated by the winding rotates approximately around the axis, and the windings are connected to each other in series using metal copper wires; each winding is wound with 8 turns of 1mm diameter enameled wire, the coil height is 58mm, the working voltage is 336V, and the magnetic field generated ranges from 0.04 to 0.06T.

8. The synchronous magnetic drive medium frequency sliding arc plasma generating device according to claim 1, characterized in that: Synchronous control is used to achieve magnetic field generation. Both independent half-bridge circuits use 48V DC input. Two groups of MOSFETs are alternately turned on at a frequency of 20kHz. The two groups of MOSFETs are marked as Q1, Q2 and Q3, Q4, respectively, which drive the axial excitation coil on the surface of the outer cylinder and the internal series winding to generate a magnetic field. The system uses 15kV / 20kHz sinusoidal AC as the reference source. Two sets of complementary PWM signals are generated through the synchronous driver to accurately control the timing of the four MOSFETs to ensure phase synchronization of the magnetic field.

9. The synchronous magnetic drive medium frequency sliding arc plasma generating device according to claim 8, characterized in that: When the reference AC power supply is in the positive half cycle, the current direction in the reaction zone is from the inner electrode to the inner cylinder; the gate drive signal of Q1 is 0V, and the gate drive signal of Q2 is 15V, that is, Q1 is in the off state and Q2 is in the on state; at this time, square wave signal 1 excites the excitation coil to generate a magnetic field with a direction downward along the axis of the device; under the action of this magnetic field, the charged particles inside the reaction zone will be affected by the Lorentz force, causing the arc trajectory to rotate counterclockwise along the inner electrode in the plane; at the same time, the gate drive signal of Q4 is 0V, and the gate drive signal of Q3 is 15V; that is, Q4 is in the off state and Q3 is in the on state; at this time, square wave signal 2 excites the series winding, and the coupling generates a magnetic field with a direction approximately counterclockwise rotating around the axis of the device, which causes the arc to be subjected to a Lorentz force with a direction upward along the axis; under the action of the two magnetic fields, the arc trajectory will spiral upward counterclockwise along the inner electrode.

10. The synchronous magnetic drive medium frequency sliding arc plasma generating device according to claim 8, characterized in that: When the reference AC power supply is in the negative half cycle, the output signal direction is reversed, and the current direction in the reaction zone is from the inner cylinder to the inner electrode; Q1 is in the on state, Q2 is in the off state; Q4 is in the on state, Q3 is in the off state; the output signal directions of square wave signals 1 and 2 are reversed. At this time, the excitation coil generates a magnetic field with an upward direction along the axis of the device; under the action of this magnetic field, the charged particles inside the reaction zone are affected by the Lorentz force, and the arc trajectory rotates counterclockwise along the inner electrode in the plane; the magnetic field coupling between the windings generates a magnetic field with a direction approximately rotating clockwise around the axis of the device, so that the arc is still affected by the Lorentz force with an upward direction along the axis.

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