A laser-triggered gap series multi-gap vacuum switch with non-uniform gaps

Abstract

The application belongs to the technical field of high-voltage and high-power pulse power switch, and particularly relates to a laser-triggered gap series multi-gap vacuum switch with uneven gaps. The switch comprises a laser-triggered gap, a self-breakdown gap and a laser-triggering system; the end of the cathode conductive rod of the laser-triggered gap is a screw rod structure, the end of the anode conductive rod of the multi-stage self-breakdown vacuum gap is a nut structure, and the two gaps are connected by a modular threaded structure; the application adopts the series connection technology of the laser-triggered vacuum gap and the multi-stage self-breakdown vacuum gap, and the length of each gap of the self-breakdown gap is designed in a step-by-step increasing manner, so as to effectively shorten the conduction time of the first several self-breakdown gaps and improve the conduction performance of the switch; by connecting high-voltage non-inductive resistors (coupling resistors) in parallel at the two ends of each gap, the voltage distribution between the self-breakdown gaps is regulated, so that the voltage distribution of the vacuum gaps in the earlier stages is larger, the breakdown time is shorter, and the conduction of the front vacuum switch is further accelerated.

Description

Technical Field

[0001] This invention belongs to the field of high-voltage high-power pulse power switch technology, specifically relating to a laser-triggered gap series multi-gap vacuum switch with non-uniform gaps. Background Technology

[0002] Pulsed power technology is one of the major fundamental disciplines of modern science and technology. It studies the electrophysical technology of storing low-power electrical energy, rapidly compressing and converting it, and then effectively releasing it to a load in a very short time. The development of pulsed power technology is of great significance to my country's high-tech scientific and technological research and national defense research. Switches, as one of the key components of pulsed power devices, not only isolate charging and discharging circuits but also transform and steepen pulse waveforms. The performance of switches directly determines key technical indicators such as the safety, power transmission quality, and reliability of electrical equipment. With the rapid development of pulsed power technology, pulsed power devices are increasingly widely used in integrated circuits, environmental engineering, medical fields, and other areas. These applications place higher demands on switch performance, mainly requiring high voltage resistance, short trigger delay, miniaturization, high repetition frequency, and long lifespan.

[0003] There are many types of switching devices in pulsed power technology. Based on their switching function, they can be divided into two main categories: closing switches and opening switches. This paper mainly focuses on closing switches. According to the type of insulating medium, closing switches can be divided into gas switches, solid-state switches, liquid switches, and plasma switches. Vacuum switches, as a type of gas switch, use a vacuum medium in their main gap. They feature large current carrying capacity, high insulation, and high arc-extinguishing level, making them widely used in large-scale pulsed power devices. Based on the different triggering methods, they can be divided into electrical pulse-triggered switches and laser pulse-triggered switches. Electrically triggered switches are powered by an external trigger power supply, which supplies power to the trigger circuit. The discharge of the trigger circuit generates initial plasma to turn on the switch. Electrically triggered switches can be further divided into field breakdown type electrically triggered vacuum switches and surface flashover type electrically triggered vacuum switches. Field breakdown type electrically triggered vacuum switches require a higher trigger voltage, resulting in larger trigger delays and jitter. While surface flashover type electrically triggered vacuum switches do not require a very high trigger voltage, the metal vapor generated during discharge cools and deposits on the surface material, causing a drop in trigger voltage and thus a shorter lifespan. Laser-triggered vacuum switches (LTVS) combine the advantages of vacuum switch technology and pulsed laser technology. They not only achieve the good control accuracy and stability of laser triggering control but also avoid the problems of severe electrode ablation, poor operational stability, prolonged trigger time, and high trigger threshold associated with gas switches. The switching device exhibits excellent conduction characteristics.

[0004] Due to the saturation effect between the vacuum gap breakdown voltage and the electrode spacing, it is difficult to improve the withstand voltage level of LTVS. Currently, existing research at home and abroad generally uses multiple vacuum gaps in series to solve this problem. Most studies improve the withstand voltage by using a laser-triggered gap in series with multiple self-breaking-down vacuum gaps. The working process involves a pulsed laser irradiating the target to generate initial plasma. The voltage of the first-stage laser-triggered gap begins to decrease. Subsequently, the laser-triggered gap voltage is superimposed on the subsequent cascaded gaps in the form of an impulse voltage. Therefore, during the successive conduction of the subsequent cascaded gaps, they are subjected to two voltages—the gap's DC operating voltage and a steep impulse voltage. Under the combined action of these two operating voltages, the series vacuum gaps break down step by step, eventually closing the switch. In this switch structure, the breakdown process of each gap is related to the interaction between the gaps. The later the gap breakdown sequence, the steeper the superimposed impulse voltage and the shorter the breakdown delay. However, the first few vacuum gaps have a smaller superimposed impulse voltage and a longer breakdown delay, resulting in a longer overall switch conduction delay. Therefore, a reasonable switch structure design and attention to the coordination between gaps are necessary to effectively shorten the switch conduction delay. Summary of the Invention

[0005] This invention proposes a multi-gap vacuum switch for pulsed power systems with non-uniformly spaced laser-triggered gaps connected in series. The gap length from the first to the last stage is designed to increase progressively in a certain proportion, resulting in lower breakdown voltages for the earlier stages of the vacuum gaps. This solves the problem of long breakdown times for the first few stages of the laser-triggered multi-stage vacuum switch. This switch improves the withstand voltage rating while reducing the overall switch's turn-on delay and jitter, giving the laser-triggered vacuum switch superior conduction characteristics. By rationally designing the structure of each gap electrode and utilizing the interaction between the magnetic fields of each gap, the switch's repetition rate breaking capability can be improved. Connecting high-voltage non-inductive resistors in parallel across each gap allows for adjustment of the voltage division relationship between the gaps, resulting in larger voltage divisions for the earlier stages of the vacuum gaps, thereby accelerating the gap breakdown time and shortening the overall switch's turn-on delay.

[0006] The technical solution of the present invention:

[0007] A laser-triggered gap series multi-gap vacuum switch with non-uniform gaps includes a laser-triggered gap, a self-breakdown gap, and a laser-triggered system;

[0008] The cathode conductive rod end of the laser trigger gap has a screw structure, and the anode conductive rod end of the multi-stage self-breakdown vacuum gap has a nut structure. The two gaps are connected by a modular threaded structure.

[0009] The laser trigger gap includes an anode conductive rod with a light-transmitting hole, an upper end cap, an upper insulating shell, a lower end cap, a cathode conductive rod, an anode with a light-transmitting hole, a cathode with a groove, a shield, a target material, and a light-transmitting lens;

[0010] The light-transmitting lens needs to be selected according to the laser wavelength, and together with the anode conductive rod with light-transmitting hole, the upper end cover, the upper insulating shell, the lower end cover, and the cathode conductive rod, it forms a vacuum cavity with a certain degree of vacuum.

[0011] The laser trigger gap shield is fixed inside the upper insulating shell to optimize the electric field distribution within the laser trigger vacuum gap and suppress arc sputtering; the axes of the light-transmitting lens, the anode conductive rod with a light-transmitting hole, the anode with a light-transmitting hole, the cathode with a groove, and the cathode conductive rod are on the same straight line; the target material is placed in the cathode groove, and the surface of the target material is slightly lower than the surface of the cathode with a groove.

[0012] The multi-stage self-breakdown vacuum gap includes an anode conductive rod, an upper end cover, a lower insulating shell, a lower end cover, a cathode conductive rod, a shielding cover, a supporting insulator, and an annular self-breakdown electrode;

[0013] The multi-stage self-breakdown vacuum gap consists of an anode conductive rod, an upper end cover, a lower insulating shell, a lower end cover, and a cathode conductive rod, forming a vacuum cavity with a certain degree of vacuum.

[0014] The multi-stage self-breakdown vacuum gap shield is fixed on the lower insulating shell to optimize the electric field distribution within the multi-stage self-breakdown vacuum gap and suppress arc splashing; the axes of the anode conductive rod, anode, supporting insulator, annular self-breakdown electrode, cathode, and cathode conductive rod are located on the same straight line;

[0015] The series of annular self-breaking electrodes and supporting insulators are fixed inside the shielding cover;

[0016] The supporting insulator is a columnar object with a cylindrical protrusion at the top and a cylindrical groove at the bottom, and has an umbrella skirt. The topmost supporting insulator is connected to the anode conductive rod. The length of the supporting insulator increases gradually from the first level to the last level in a certain proportion. The supporting insulators cooperate with each other to sandwich the inner rings of multiple annular self-breakdown electrodes in the middle.

[0017] The bottom surface of the multi-stage self-breaking cathode conductive rod has a protrusion that matches the support insulator. The upper protrusion is connected to the groove at the bottom of the support insulator via the last stage annular self-breaking electrode, and the lower end passes through the self-breaking lower end cover for sealing and fixing.

[0018] The series-connected annular self-breakdown electrodes include one or more of the following structures: planar type, longitudinal magnetic type, and transverse magnetic type.

[0019] The diameter of the hollow circle in the middle of the annular self-breakdown electrode is equal to the diameter of the raised cylinder on the upper part of the supporting insulator. The thickness of the inner ring sheet of the electrode is smaller than that of the outer ring and it is integrally connected. The outer ring part is the main discharge electrode. After the series gap is turned on, the current flows through the outer ring part. Changing the structure of the outer ring part can change the magnitude and direction of the magnetic field in the gap when the current flows. The inner ring of the first-stage annular self-breakdown electrode is sandwiched between the high-voltage conductive rod and the supporting insulator. In this way, a multi-stage self-breakdown vacuum gap is formed in series.

[0020] The laser triggering system includes a transmission optical fiber, a laser, a trigger controller, and a focusing lens;

[0021] In the non-uniformly spaced laser-triggered gap series multi-gap vacuum switch, before receiving a trigger signal, each gap bears the static operating voltage according to the voltage division relationship. When the trigger signal is issued, a laser pulse is generated. After the laser pulse is focused by the focusing lens, the pulsed laser passes through the light-transmitting lens and bombards the target material to generate initial plasma. The laser-triggered gap is turned on under the action of the static operating voltage and the initial plasma. After the laser-triggered gap is triggered, since the switch is not yet turned on, the voltage it bears statically will be superimposed on the cascaded gaps in the form of a steep impulse voltage. Because the length of the first few self-breakdown gaps is relatively short, under the combined action of the gap DC operating voltage and the steep impulse voltage, the first few self-breakdown gaps are turned on first, and the series of short vacuum gaps break down step by step, eventually closing the switch.

[0022] The beneficial effects of this invention are:

[0023] This invention employs laser-triggered vacuum gap and multi-stage self-breakdown vacuum gap series technology, enabling the switch to be applied in high-voltage, high-power pulse power systems. The length of each self-breakdown gap is designed to increase progressively, effectively shortening the conduction time of the first few stages and improving the switch's conduction performance. By connecting high-voltage non-inductive resistors (coupling resistors) in parallel across each gap to regulate the voltage division between the self-breakdown gaps, the earlier the stage, the greater the voltage division and the shorter the breakdown time, further accelerating the conduction of the first few stages and achieving a superior conduction delay. By changing the combination of the self-breakdown ring electrodes and utilizing the interaction of the magnetic fields generated between the electrodes, the switch's repetition rate breaking capability can be improved. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a multi-gap vacuum switch structure with non-uniform gap laser triggering gap connected in series.

[0025] Figure 2 This is a schematic diagram of the internal structure of a multi-gap vacuum switch with non-uniform laser trigger gaps connected in series.

[0026] Figure 3 This is a schematic diagram of a laser triggering system;

[0027] Figure 4 This is a schematic diagram of the coupling resistors for each gap.

[0028] In the diagram: 1. Anode conductive rod with light-transmitting hole; 2. Upper end cap; 3. Upper insulating shell; 4. Lower end cap; 5. Cathode conductive rod; 6. Anode with light-transmitting hole; 7. Cathode with groove; 8. Target material; 9. Shielding cover; 10. Light-transmitting lens; 11. Anode conductive rod; 12. Upper end cap; 13. Lower insulating shell; 14. Lower end cap; 15. Cathode conductive rod; 16. Annular self-breaking electrode; 18. Support insulator; 19. Shielding cover; 20. Signal transmission optical fiber; 21. Laser; 22. Trigger controller; 23. Focusing lens; 24. Coupling resistor; 25. Coupling resistor. Detailed Implementation

[0029] The specific embodiments of the present invention are described in detail below with reference to the technical solutions and accompanying drawings.

[0030] Example 1:

[0031] Combination Figures 1-4 A multi-gap vacuum switch with non-uniform gap laser triggering gap connected in series includes a laser triggering vacuum gap, a self-breakdown gap, and a laser triggering system;

[0032] Before triggering, the static operating voltage of the pulse power system is mainly borne by the laser trigger vacuum gap and the multi-stage self-breakdown gap. The static operating voltage is obtained from the system through coupling resistors 23, 24, and 25.

[0033] When the laser-triggered gap series multi-gap vacuum switch with non-uniform gaps is not conducting, adjusting coupling resistors 23, 24, and 25 can change the voltage division ratio between each gap, improve the internal voltage distribution of the multi-gap laser-triggered vacuum switch, accelerate the conduction of the first few self-breakdown gaps, and enable the switch to obtain a better conduction delay.

[0034] When the trigger controller 21 receives the trigger command, the trigger signal is transmitted to the laser 20 through the signal transmission fiber optic cable 19. After the laser outputs a laser pulse, the pulsed laser is focused by the focusing lens 22 and passes through the light transmission lens 10 to irradiate the surface of the target material 8, generating initial plasma. The laser trigger gap is turned on under the action of the static working voltage and the initial plasma. After the laser trigger gap is turned on, the static voltage it borne before the turn-on will be superimposed on the subsequent multi-stage self-breakdown gaps in the form of an impulse voltage. Under the combined action of the static working voltage and the superimposed impulse voltage, the outer ring of the annular self-breakdown electrode 16 breaks down step by step, completing the conduction of the multi-gap vacuum switch. During the switch conduction process, under the action of the annular self-breakdown electrodes 16 with different structures, magnetic fields in different directions are formed in each stage of the vacuum gap and produce a synergistic effect. By utilizing the mutual cooperation of the magnetic fields of each gap, the diffusion motion and cooling process of the electric arc in the gap can be accelerated, realizing the rapid conduction of the multi-gap laser-triggered vacuum switch.

[0035] Example 2:

[0036] Combination Figures 1-4 A laser-triggered gap series multi-gap vacuum switch with non-uniform gaps, comprising a laser-triggered vacuum gap, a self-breakdown gap, and a laser-triggered system;

[0037] The cathode conductive rod 5 of the laser trigger gap has a screw structure at its end, and the anode conductive rod 11 of the multi-stage self-breakdown vacuum gap has a nut structure at its end. The two gaps are connected by a modular threaded structure.

[0038] The laser trigger gap includes an anode conductive rod 1 with a light-transmitting hole, an upper end cover 2, an upper insulating shell 3, a lower end cover 4, a cathode conductive rod 5, an anode 6 with a light-transmitting hole, a cathode 7 with a groove, a shield 9, a target material 8, and a light-transmitting lens 10.

[0039] The light-transmitting lens needs to be selected according to the laser wavelength, and together with the anode conductive rod 1 with light-transmitting hole, the upper end cover 2, the upper insulating shell 3, the lower end cover 4, and the cathode conductive rod 5, they form a vacuum cavity with a certain degree of vacuum.

[0040] Inside the laser-triggered vacuum gap, a shield 9 is fixed to the upper insulating shell 3 to optimize the electric field distribution within the laser-triggered vacuum gap and suppress arc sputtering; the axes of the light-transmitting lens 10, the anode conductive rod 1 with a light-transmitting hole, the anode 6 with a light-transmitting hole, the cathode 7 with a groove, and the cathode conductive rod 5 are on the same straight line; the target material 8 is placed in the cathode groove 7, and the surface of the target material 8 is slightly lower than the surface of the cathode 7 with a groove.

[0041] The multi-stage self-breakdown vacuum gap includes an anode conductive rod 11, an upper end cover 12, a lower insulating shell 13, a lower end cover 14, a cathode conductive rod 15, a shielding cover 18, a supporting insulator 17, and an annular self-breakdown electrode 16.

[0042] The multi-stage self-breakdown vacuum gap is composed of an anode conductive rod 11, an upper end cover 12, a lower insulating shell 13, a lower end cover 14, and a cathode conductive rod 15, forming a vacuum cavity with a certain degree of vacuum.

[0043] The multi-stage self-breakdown vacuum gap shield 18 is fixed on the lower insulating shell 13 to optimize the electric field distribution in the multi-stage self-breakdown vacuum gap and suppress arc splashing; the axes of the anode conductive rod 11, the supporting insulator 17, the annular self-breakdown electrode 16 and the cathode conductive rod 15 are on the same straight line.

[0044] The series of annular self-breaking electrodes 16 and supporting insulators 17 are fixed inside the shielding cover 18;

[0045] The supporting insulator 17 is a columnar object with a cylindrical protrusion at the top and a cylindrical groove at the bottom, and has an umbrella skirt. The topmost supporting insulator is connected to the anode conductive rod. The length of the supporting insulator increases gradually from the first level to the last level in a certain proportion. The supporting insulators cooperate with each other to sandwich the inner rings of multiple annular self-breakdown electrodes 16 in the middle.

[0046] The bottom surface of the multi-stage self-breaking cathode conductive rod 15 has a protrusion that matches the support insulator 17. The upper protrusion is connected to the groove at the bottom of the support insulator 17 via the last stage annular self-breaking electrode 16, and the lower end passes through the self-breaking lower end cover 14 for sealing and fixing.

[0047] The series-connected annular self-breakdown electrode 16 includes a combination of one or more structures of the following types: planar, longitudinal magnetic, and transverse magnetic.

[0048] The diameter of the hollow circle in the middle of the annular self-breakdown electrode 16 is equal to the diameter of the upper protruding cylinder of the supporting insulator 17. The thickness of the inner ring sheet of the electrode is smaller than that of the outer ring and it is integrally connected. The outer ring part is the main discharge electrode. After the series gap is turned on, the current flows through the outer ring part. Changing the structure of the outer ring part can change the magnitude and direction of the magnetic field in the gap when the current flows. The inner ring of the first-stage annular self-breakdown electrode 16 is sandwiched between the anode conductive rod 11 and the supporting insulator 17. In this way, a multi-stage self-breakdown vacuum gap is formed in series.

[0049] The laser triggering system includes a transmission fiber 19, a laser 20, a trigger controller 21, and a focusing lens 22;

[0050] Before receiving a trigger signal, the non-uniformly spaced laser-triggered gap series multi-gap vacuum switch borne static operating voltage according to the voltage division relationship among the gaps. When the trigger signal is issued, a laser pulse is generated. After the laser pulse is focused by the focusing lens 22, the pulsed laser passes through the light-transmitting lens 10 and bombards the target material 8 to generate initial plasma. The laser-triggered gap is turned on under the action of the static operating voltage and the initial plasma. After the laser-triggered gap is triggered, since the switch is not turned on at this time, the voltage it statically bears will be superimposed on the cascaded gap in the form of a steep impulse voltage. Since the length of the first few self-breakdown gaps is relatively short, under the combined action of the gap DC operating voltage and the steep impulse voltage, the first few self-breakdown gaps are turned on first, and the series of short vacuum gaps break down step by step, eventually closing the switch.

Claims

1. A laser-triggered multi-gap vacuum switch with non-uniform gaps in series, characterized in that, This includes laser trigger gaps, multi-stage self-breakdown gaps, and laser triggering systems; The cathode conductive rod (5) of the laser trigger gap has a screw structure at its end, and the anode conductive rod (11) of the multi-stage self-breakdown gap has a nut structure at its end. The two gaps are connected by a modular threaded structure. The laser trigger gap includes an anode conductive rod (1) with a light-transmitting hole, an upper end cover (2), an upper insulating shell (3), a lower end cover (4), a cathode conductive rod (5), an anode (6) with a light-transmitting hole, a cathode (7) with a groove, a shield (9), a target material (8), and a light-transmitting lens (10). The multi-stage self-breakdown gap includes an anode conductive rod (11), an upper end cover (12), a lower insulating shell (13), a lower end cover (14), a cathode conductive rod (15), a shield (18), a supporting insulator (17), and an annular self-breakdown electrode (16). The multi-stage self-breakdown gap is composed of an anode conductive rod (11), an upper end cover (12), a lower insulating shell (13), a lower end cover (14), and a cathode conductive rod (15), forming a vacuum cavity with a vacuum degree. The shield (18) of the multi-stage self-breakdown gap is fixed on the lower insulating shell (13); the axes of the anode conductive rod (11), the supporting insulator (17), the annular self-breakdown electrode (16) and the cathode conductive rod (15) are on the same straight line; The series of multiple annular self-breaking electrodes (16) and supporting insulators (17) are fixed inside the shield (18); The supporting insulator (17) is a column with a slatted skirt, with a cylindrical protrusion at the top and a cylindrical groove at the bottom. The top supporting insulator is connected to the anode conductive rod. The length of the supporting insulator increases gradually from the first level to the last level in a certain proportion. Each supporting insulator cooperates with the others to sandwich the inner rings of multiple annular self-breakdown electrodes (16) in the middle. The bottom surface of the multi-stage self-breakdown cathode conductive rod (15) has a protrusion that matches the support insulator (17). Its upper protrusion is connected to the groove at the bottom of the support insulator (17) via the last stage annular self-breakdown electrode (16), and its lower end passes through the self-breakdown lower end cover (14) for sealing and fixing. The diameter of the hollow circle in the middle of the annular self-breakdown electrode (16) is equal to the diameter of the upper protruding cylinder of the supporting insulator (17). The thickness of the inner ring sheet of the electrode is smaller than that of the outer ring and is integrally connected with it. The outer ring part is the main discharge electrode. After the series gap is turned on, the current flows through the outer ring part. Changing the structure of the outer ring part can change the magnitude and direction of the magnetic field in the gap when the current flows. The inner ring of the first-stage annular self-breakdown electrode (16) is sandwiched between the anode conductive rod (11) and the supporting insulator (17), forming a multi-stage self-breakdown gap in series.

2. A laser-triggered gap series multi-gap vacuum switch with non-uniform gaps as claimed in claim 1, wherein, Inside the laser trigger gap, the shield (9) is fixed on the upper insulating shell (3); the axes of the light-transmitting lens (10), the anode conductive rod (1) with light-transmitting hole, the anode (6) with light-transmitting hole, the cathode (7) with groove and the cathode conductive rod (5) are on the same straight line; the target material (8) is placed in the cathode groove 7, and the surface of the target material (8) is slightly lower than the surface of the cathode (7) with groove.

3. A laser-triggered gap series multi-gap vacuum switch with non-uniform gap as described in claim 1 or 2, characterized in that, The light-transmitting lens (10), the anode conductive rod (1) with light-transmitting hole, the upper end cover (2), the upper insulating shell (3), the lower end cover (4), and the cathode conductive rod (5) form a vacuum cavity with a certain degree of vacuum.

4. A laser-triggered gap series multi-gap vacuum switch with non-uniform gap as described in claim 1 or 2, characterized in that, The ring-shaped self-breakdown electrode (16) includes a combination of one or more structures of the following types: flat plate, longitudinal magnetic, and transverse magnetic.

5. A laser-triggered gap series multi-gap vacuum switch with non-uniform gap as described in claim 3, characterized in that, The ring-shaped self-breakdown electrode (16) includes a combination of one or more structures of the following types: flat plate, longitudinal magnetic, and transverse magnetic.

6. A laser-triggered gap series multi-gap vacuum switch with non-uniform gap as described in claim 1, characterized in that, The length of each gap in the multi-stage self-breakdown gap is designed to increase progressively.

7. A laser-triggered gap series multi-gap vacuum switch with non-uniform gap as described in claim 1, characterized in that, The laser-triggered gap series multi-gap vacuum switch obtains the static working voltage from the system through coupling resistors (23), (24), and (25), changes the voltage division ratio between each gap, and improves the internal voltage distribution of the multi-gap laser-triggered vacuum switch.

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