Micro-cathode arc thruster

Abstract

The invention discloses a micro-cathode arc thruster, and relates to the technical field of satellite micro-propulsion, and the micro-cathode arc thruster comprises a cathode, a plurality of anodes and an insulator; the plurality of anodes are arranged around the cathode; the insulator is filled in a gap between the cathode and each anode; the micro-cathode arc thruster comprises a plurality of anodes, each anode corresponds to a trigger pulse, time delay exists between the trigger pulses corresponding to the adjacent anodes so that each anode and the cathode can alternately discharge, the micro-cathode arc thruster can continuously discharge by arranging the anodes and the cathode to alternately discharge, thrust is continuously provided, and the thrust efficiency is improved. And the system works in a quasi-steady state mode.

Description

Technical Field

[0001] This application relates to the field of satellite micro-propulsion technology, and in particular to a micro-cathode arc thruster. Background Technology

[0002] Microcathode arc thrusters, with their advantages of high specific impulse, low power consumption, low discharge voltage, high efficiency, wide thrust adjustment range, low cost, long life and high reliability, have become one of the propulsion methods for small satellite attitude control and orbit correction.

[0003] Traditional microcathode arc thrusters operate in pulse mode, and the thrust they generate is output in the form of pulses. This makes it impossible to output thrust evenly and stably. At the same time, the short-term high-frequency discharge may damage the electrical components in the power processing unit (PPU) circuit system, which greatly limits the fields in which it can be used. Summary of the Invention

[0004] The purpose of this application is to provide a microcathode arc thruster that can continuously discharge, thereby continuously providing thrust and operating in a quasi-steady-state manner.

[0005] To achieve the above objectives, this application provides the following solution.

[0006] This application provides a microcathode arc thruster, comprising: a cathode, a plurality of anodes and an insulator; the plurality of anodes are arranged around the cathode; the insulator fills the gap between the cathode and each anode; each anode corresponds to a trigger pulse, and the trigger pulses corresponding to adjacent anodes have a time delay, so that each anode alternately discharges with the cathode.

[0007] Based on the specific embodiments provided in this application, the following technical effects are disclosed.

[0008] This application provides a microcathode arc thruster. By designing multiple anodes, the current passing through a single anode at the same time is evenly distributed across multiple anodes, reducing the time-averaged current on a single anode and effectively protecting the PPU circuit system. By arranging multiple anodes around the cathode, the uniformity of the electric field and current density can be improved, thereby increasing pulse triggering efficiency, the lifespan and stability of the microcathode arc thruster. By setting a time delay between the trigger pulses corresponding to adjacent anodes, the microcathode arc thruster can achieve sequential discharge of different anodes and cathodes within one cycle while maintaining the single anode pulse discharge unchanged, providing a near-stable thrust, thus enabling the microcathode arc thruster to operate in a quasi-steady-state manner. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of the structure of a microcathode arc thruster in one embodiment of this application.

[0011] Figure 2 This is a schematic diagram of the structure of a conventional microcathode arc thruster provided in an embodiment of this application.

[0012] Figure 3 A schematic diagram of the discharge waveform of a conventional microcathode arc thruster provided in an embodiment of this application.

[0013] Figure 4 This is a side sectional view of a microcathode arc thruster provided in an embodiment of this application.

[0014] Figure 5 This is a schematic diagram of the assembly of a microcathode arc thruster provided in an embodiment of this application.

[0015] Figure 6 A front view of a plurality of anodes provided in an embodiment of this application.

[0016] Figure 7 A side view of a plurality of anodes provided in an embodiment of this application.

[0017] Figure 8 An oblique view of a plurality of anodes provided in an embodiment of this application.

[0018] Figure 9 A front view of a single anode provided in an embodiment of this application.

[0019] Figure 10 A side view of a single anode provided in an embodiment of this application.

[0020] Figure 11 An oblique view of a single anode provided in an embodiment of this application.

[0021] Figure 12 This is a front view of an insulating ceramic electrode between the anode and cathode provided in an embodiment of this application.

[0022] Figure 13 A side view of an insulating ceramic electrode between the anode and cathode provided in an embodiment of this application.

[0023] Figure 14 An oblique view of an insulating ceramic electrode between the anode and cathode provided in an embodiment of this application.

[0024] Figure 15 This refers to the control level signal corresponding to each switching circuit provided in one embodiment of this application.

[0025] Figure 16 This is a schematic diagram of the arc current variation of a microcathode arc thruster provided in an embodiment of this application.

[0026] Figure label.

[0027] 1-Cathode, 2-Anode, 3-Insulator, 4-Insulating support, 5-Permanent magnet, 6-Storage bin, 7-Cathode working medium, 8-Bolt, 9-Insulating ceramic rear column, 10-Ring insulating support, 11-Feeding pipe, 12-Nut, 13-Conductive coating. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] In one exemplary embodiment, such as Figure 1 As shown, a microcathode arc thruster is provided, comprising: a cathode 1, multiple anodes 2 and an insulator 3.

[0031] Multiple anodes 2 are arranged around the cathode 1. The insulator 3 fills the gap between the cathode 1 and each anode. Each anode corresponds to a trigger pulse, and the trigger pulses of adjacent anodes are time-delayed, so that each anode discharges alternately with the cathode 1.

[0032] In one example, the cathode 1 has a columnar structure. Multiple anodes 2 are arranged in a ring, with the cathode 1 located at the center of the ring. The insulator 3 is an insulating ceramic, and the insulating ceramic is coated with a conductive coating at the electrical connection points between the cathode and each anode.

[0033] In one example, the microcathode arc thruster further includes: a cathode working medium and a storage bin and a supply pipe connected in sequence. The cathode working medium is stored in the storage bin and enters the supply pipe through the storage bin to form the cathode 1.

[0034] like Figure 2As shown, a traditional microcathode arc thruster includes a cathode 1, an insulating support 4, an anode 2, and a permanent magnet 5. According to... Figure 3 As shown in the discharge waveform diagram of the traditional microcathode arc thruster, the arc current duration of the traditional microcathode arc thruster in single-pulse discharge mode is relatively short, which makes it impossible to achieve long-term continuous discharge, resulting in low energy output efficiency and limited process controllability.

[0035] Unlike traditional microcathode arc thrusters, the microcathode arc thruster of this application adopts the following... Figure 1 The diagram shows multiple annular anodes replacing the monolithic anode structure. Cathode 1 retains its original columnar structure, and multiple anodes 2 are coaxial with insulator 3 and cathode 1. The number of anodes is determined by the performance parameters required by the microcathode arc thruster and the voltage signal parameters that the PPU circuit system can provide. The purpose of designing multiple annular anodes is to apply appropriate signal parameters sequentially to different anodes, allowing the microcathode arc thruster to achieve sequential discharge of different anodes and cathodes within one cycle. This ultimately enables the microcathode arc thruster to continuously discharge within one cycle, providing a near-stable thrust.

[0036] Faced with the ever-changing thrust requirements of spacecraft, traditional microcathode arc thrusters can often only meet these requirements by adjusting the feed voltage and discharge frequency. However, the microcathode arc thruster with multiple anodes mentioned in this application can meet these requirements by reasonably adjusting the number of anodes, the delay time between the start of discharge of two adjacent anodes, the discharge frequency, and the feed voltage, thus giving it a wider thrust adjustment range.

[0037] This quasi-steady-state discharge mode has two advantages: First, it does not change the discharge characteristics of traditional pulse-operated microcathode arc thrusters, which are characterized by "high pulse peak current and low average current," effectively protecting the electrical components of the PPU circuit system and the various structures of the microcathode arc thruster. Second, the next pulse discharge of the microcathode arc thruster will start before the previous pulse discharge has ended. Since there is still plasma between the anode and cathode that can achieve conductivity, the ignition difficulty during the subsequent start-up is effectively reduced.

[0038] Furthermore, the multiple anode configuration retains the advantages of traditional microcathode arc thrusters, which reduce ignition difficulty through pulsed discharge and lower the average current across the circuit to prevent damage to electrical components in the PPU circuit system. Traditional microcathode arc thrusters can also achieve this steady-state discharge by simply increasing the discharge frequency; however, this increase in frequency significantly increases the average current across the circuit, greatly increasing the stress on the PPU circuit system. This application, through its multi-anode design, distributes the current passing through a single anode across multiple anodes simultaneously, reducing the average current across a single anode and effectively protecting the PPU circuit system.

[0039] In one example, such as Figure 4 and Figure 5 As shown, the microcathode arc thruster provided in this application includes a storage bin 6, a cathode working medium 7, bolts 8, an insulating ceramic rear column 9, an annular insulating support 10, a feeding pipe 11, multiple anodes 2, an insulator 3, a permanent magnet 5, an insulating support 4, and a nut 12. The storage bin 6 is connected to the feeding pipe 11 via an internal thread. The cathode working medium 7 is stored inside the storage bin 6 and is forced in through the storage bin 6 when needed. The insulating ceramic rear column 9 and the annular insulating support 10 are used to fix the feeding pipe 11, which supplies the liquid metal cathode working medium 7. The insulator 3 is used to reduce the resistance between the anode and cathode of the microcathode arc thruster. The permanent magnet 5 is directly fixed between the insulator 3 and the insulating support 4, and is fixed by fitting onto the bosses of the two structures. The cathode 1 is located on the central shaft of the microcathode arc thruster. To accommodate the assembly of multiple anodes 2, the insulator 3 has a multi-segmented grooved structure, and the anodes 2 can be inserted into the grooves on the insulator 3 and fixed. The actual number of anodes in the assembly can be changed by designing the size and number of slots in insulator 3 and the size and number of anodes 2. The main components are connected by bolts 8 and nuts 12.

[0040] In one example, such as Figure 6 , Figure 7 and Figure 8 As shown, the multiple anodes 2 are not interconnected, but are composed of individual anodes. The structure of a single anode is as follows: Figure 9 , Figure 10 and Figure 11 As shown in the figure. In this example, the number of anodes is 20. This number can be designed according to spacecraft requirements, the size and structure of the microcathode arc thruster, as well as manufacturing capabilities and the tolerance of the circuit system. Multiple anodes 2 are arranged in a ring around cathode 1, clockwise from anode 1 to anode 20, thus achieving quasi-steady-state discharge of the microcathode arc thruster. In this example, the anodes are separated by insulating ceramic coated with a conductive layer to prevent conductivity. The structure of the insulating ceramic is shown in the figure. Figure 12 , Figure 13 and Figure 14As shown. Figure 12 As shown, the insulating ceramic is coated with a conductive coating 13 only on the portion between the anode and cathode.

[0041] In one example, the microcathode arc thruster further includes a power processing unit. The power processing unit is used to send trigger pulses to each anode.

[0042] In one example, the power processing unit includes multiple parallel switching circuits, and each switching circuit corresponds to an anode; the power processing unit sends a trigger pulse with a time delay to each anode by controlling the on / off state of each switching circuit.

[0043] In one example, the trigger pulse waveform is identical for each anode, and the time delay between trigger pulses for adjacent anodes is the same. At the start of operation of the microcathode arc thruster, a signal is sent to each switching circuit as follows: Figure 15 The control level signal is shown. By controlling the control level signal of the switching circuit between different anodes 2 and cathodes 1, the start time of discharge between different anodes 2 and cathodes 1 can be controlled. This allows the microcathode arc thruster to start the discharge of the next anode and cathode before the discharge between the previous anode and cathode has ended, enabling the microcathode arc thruster to achieve... Figure 16 The near-stable discharge shown leads to stable thrust output.

[0044] The discharge period and frequency of the microcathode arc thruster, as well as the number of anodes and the discharge delay time between each anode, can be set according to the performance parameters provided by the desired microcathode arc thruster. In one example, the pulse width of the trigger pulse is greater than the arc duration, and the period of the trigger pulse and the time delay of the trigger pulse corresponding to the adjacent anode are related as follows.

[0045] .

[0046] in, T The period of the trigger pulse, n This represents the total number of anodes. This represents the time delay of the trigger pulse corresponding to the adjacent anode.

[0047] In one example, the time delay of the trigger pulses corresponding to adjacent anodes is less than the duration of the arc. This enables the microcathode arc thruster to achieve a quasi-steady-state operating mode where the discharge of the next anode begins before the discharge of the previous anode has ended.

[0048] In another example, the time delay of the trigger pulse corresponding to adjacent anodes is 25 μs, and the pulse width of the trigger pulse is... T 1 represents 100 μs, the turn-off time. TIf 2 is 400 μs, then the period of the trigger pulse of the microcathode arc thruster is... T 500μs ( ).

[0049] To ensure stable and uniform thrust output from the microcathode arc thruster, while preventing damage to electrical components in the PPU circuit system due to short-duration, high-frequency discharges, this application replaces the traditional monolithic anode structure of microcathode arc thrusters with a multiple-anode structure. By controlling the timing of the voltage fed to each anode by the PPU circuit system, alternating discharge between each anode and cathode is achieved. This allows the microcathode arc thruster to begin discharging the next anode before the previous one has finished discharging, thus maintaining continuous discharge while preserving the pulse discharge of individual anodes. This continuous thrust allows the microcathode arc thruster to operate in a quasi-steady-state manner. Simultaneously, this output method does not increase the time-averaged current through a single anode, effectively protecting the PPU circuit system. The multiple-anode design increases the time-averaged current between the cathode and anode of the entire microcathode arc thruster, effectively improving the overall power of the microcathode arc thruster and consequently increasing the energy that can be fed into the microcathode arc thruster per unit time, thus significantly improving thrust output.

[0050] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0051] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A microcathode arc thruster, characterized in that, The microcathode arc thruster includes: a cathode, multiple anodes, and an insulator; Multiple anodes are arranged around the cathode; The insulator fills the gap between the cathode and each anode; Each anode corresponds to a trigger pulse, and there is a time delay between the trigger pulses of adjacent anodes, so that each anode discharges alternately with the cathode.

2. The microcathode arc thruster according to claim 1, characterized in that, Multiple anodes are arranged in a ring, with the cathode located at the center of the ring.

3. The microcathode arc thruster according to claim 1, characterized in that, The cathode has a columnar structure.

4. The microcathode arc thruster according to claim 1, characterized in that, The insulator is an insulating ceramic, and the insulating ceramic is coated with a conductive coating at the electrical conduction points between the cathode and each anode.

5. The microcathode arc thruster according to claim 1, characterized in that, The microcathode arc thruster also includes: a power processing unit; The power processing unit is used to send trigger pulses to each anode.

6. The microcathode arc thruster according to claim 5, characterized in that, The power processing unit includes multiple parallel switching circuits, and each switching circuit corresponds to an anode. The power processing unit sends a time-delayed trigger pulse to each anode by controlling the on / off state of each switching circuit.

7. The microcathode arc thruster according to claim 1, characterized in that, The trigger pulse waveforms for each anode are identical, and the time delay between the trigger pulses for adjacent anodes is the same.

8. The microcathode arc thruster according to claim 7, characterized in that, The pulse width of the trigger pulse is greater than the arc duration, and the period of the trigger pulse has the following relationship with the time delay of the trigger pulse corresponding to the adjacent anode: ； in, T The period of the trigger pulse, n This represents the total number of anodes. This represents the time delay of the trigger pulse corresponding to the adjacent anode.

9. The microcathode arc thruster according to claim 1, characterized in that, The time delay of the trigger pulses corresponding to adjacent anodes is less than the duration of the electric arc.

10. The microcathode arc thruster according to claim 1, characterized in that, The microcathode arc thruster also includes: a cathode working medium and a storage bin and a supply pipe connected in sequence; The cathode working medium is stored in the storage silo and enters the supply pipe through the storage silo to form the cathode.

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