Hall thruster on-orbit operational status monitoring method and system

Abstract

The present application relates to a kind of Hall thruster in-orbit operating state monitoring method and system, utilize non-invasive means to collect the discharge current of Hall thruster anode side, filter discharge current, obtain low-frequency oscillation signal, then determine the reference inflection point of scatter diagram according to low-frequency oscillation signal, and then determine the deviation rate threshold value using reference inflection point, when steady-state deviation rate is greater than deviation rate threshold value, it is judged that Hall thruster exists perturbation.The present application uses the low-frequency oscillation of discharge current that is easy to measure in the process of Hall thruster operation in orbit as state operation indicator, realizes the in-orbit monitoring of thruster operating state.

Description

Technical Field

[0001] This invention relates to the field of Hall thruster signal monitoring and analysis, and in particular to a method and system for monitoring the on-orbit operating status of a Hall thruster. Background Technology

[0002] A Hall thruster is a coaxial circular ring-shaped DC discharge plasma accelerator operating under orthogonal electromagnetic field conditions. Electrons generated at the cathode enter the thruster through a plasma bridge, are confined by an external magnetic field, collide with and ionize with neutral gas entering at the anode, and are then accelerated by an electric field to be ejected as high-speed ions, generating thrust. This unique propellant ionization and acceleration method gives it advantages over traditional chemical propulsion, such as high specific impulse, long lifespan, small size, and low pollution, leading to its widespread application in new space missions such as gravitational wave detection and low-Earth orbit constellation deployment. However, during the long-term operation of the thruster, ranging from thousands to tens of thousands of hours, system parameters inevitably degrade and environmental variables fluctuate. Therefore, obtaining and controlling the thruster's operating status remains a critical challenge.

[0003] To monitor and evaluate the operational status of thrusters, researchers have conducted in-depth studies on the performance parameters of Hall thrusters, including thrust, plume, and wall erosion. In the early stages of thruster application, pendulum thrusters (including suspended, inverted, and torsional balance configurations) were widely used to monitor thrust changes during operation in real time. However, due to the complex structure of the pendulum thruster, it could only be used for ground tests and could not achieve on-orbit measurement. Subsequently, Dan M. Goebel et al. used shielded Faraday probes, slow-velocity potential analyzers, and ExB probes to monitor plume profile plasma parameters under both "jet" and "diffusion" modes, obtaining the thruster's performance under different operating modes. Benjamin A. Jorns et al. used translational and surface probes to monitor and characterize the ion flux and energy distribution incident at the inner poles, combined with erosion model calculations, observed magnetic pole erosion, and predicted the thruster's remaining lifetime. However, probes are invasive measurements, which to some extent affect the thruster's operating environment and obscure the original perturbation signals. Subsequently, Wei Liqiu et al. proposed using a digital camera to obtain plume images, extracting RGB (red, green, and blue) data and light intensity information of different spectral lines from the plume images, and utilizing RGB data based on a collisional radiation (CR) model to measure the electron temperature distribution in the plume of an on-orbit Hall thruster. Tad Wegner et al. used two-photon absorption laser-induced fluorescence (TALIF) to monitor ground-state neutral xenon in the plume of a 1.5 kW Hall effect thruster (HET), analyzing the impact of neutral xenon particles in the plasma plume on the thruster ionization process, overall energy conversion, and wall material lifetime.

[0004] Although monitoring methods are constantly being updated and improved, the aforementioned methods mainly focus on the steady-state characteristics of thrusters under design conditions at the hourly level, with a large monitoring time span. However, the degradation and disturbances of system parameters during thruster operation are mostly weak and gradual, making them difficult to capture on the aforementioned time scale. Therefore, there is an urgent need for a method that can acquire thruster transient characteristics non-invasively and characterize the thruster's perturbation conditions. Among these methods, low-frequency oscillations, as an inherent property of plasma motion processes, have weak damping characteristics and are closely related to core physical processes in thrusters such as propellant ionization, ion acceleration, and electron conduction, thus attracting widespread attention from various countries. Furthermore, W.A. Hargus Jr. and Davide Maddaloni conducted modal analysis of low-frequency oscillations in the 1-100kHz range from both experimental measurement and data-driven perspectives, demonstrating that low-frequency oscillations can effectively reflect the transient characteristics of thrusters and obtain useful information. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for monitoring the on-orbit operation status of a Hall thruster. The method utilizes the low-frequency oscillation of the discharge current, which is easily measurable on-orbit during the operation of the Hall thruster, as a status indicator to achieve on-orbit monitoring of the thruster's operating status.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A method for monitoring the on-orbit operating status of a Hall thruster includes:

[0008] During the period from the stable start of Hall thruster operation to the first time, n sets of discharge currents on the anode side of Hall thruster are collected using non-invasive methods.

[0009] The discharge current is filtered using a fast Fourier transform to obtain n sets of low-frequency oscillation signals;

[0010] Each group of low-frequency oscillation signals is divided into multiple intervals. The median discharge current of each interval is the independent variable, and the number of discrete points of the low-frequency oscillation signal in each interval is the dependent variable. A scatter plot of each group of low-frequency oscillation signals is then drawn.

[0011] Determine the inflection point of each scatter plot, and use the mean of the n inflection points as the baseline inflection point;

[0012] The first n sets of discharge currents collected after the first time are used as background data. In the scatter plots of each set of discharge currents in the real-time discharge current group and the background data, the area enclosed by the coordinate axis from the reference inflection point to the end region is calculated to obtain the area of ​​the real-time discharge current group and the average area of ​​the background data.

[0013] The steady-state deviation rate of the real-time discharge current group is determined based on the area of ​​the real-time discharge current group and the average area of ​​the background data.

[0014] The maximum steady-state deviation rate during the period from the first time to the second time is determined as the deviation rate threshold; the second time is greater than the first time.

[0015] Compare the steady-state deviation rate of the real-time discharge current group after the second time with the deviation rate threshold. If it is greater than the deviation rate threshold, it is determined that there is a perturbation in the Hall thruster.

[0016] Optionally, determining the inflection point of each scatter plot specifically includes:

[0017] The portion of the scatter plot with a discharge current greater than zero is fitted with a polynomial to obtain the fitting function.

[0018] Calculate the second derivative of the fitted function, and simultaneously satisfy... and The point is determined as the inflection point; among them, Let x be the point j The value of the second derivative in the second derivative of the fitting function f(x).

[0019] Optionally, the step of using the first n groups of discharge currents collected after the first time as background data, and calculating the area enclosed by the coordinate axis from the reference inflection point to the end region in the scatter plots of each group of discharge currents in the real-time discharge current group and the background data respectively, to obtain the area of ​​the real-time discharge current group and the average area of ​​the background data, specifically includes:

[0020] The discharge current of the (n+l)th group is acquired in real time after the first time, and the discharge current of the (n+l-1)th group to the discharge current of the (n+l-1)th group is used as background data.

[0021] Fast Fourier Transform is used to filter the discharge currents from the l-th group to the (n+l-th)-th group to obtain the low-frequency oscillation signal of each group of discharge currents.

[0022] The low-frequency oscillation signal of each group of discharge currents is divided into multiple intervals. The median discharge current of each interval is the independent variable, and the number of discrete points of the low-frequency oscillation signal in each interval is the dependent variable. A scatter plot of each group of low-frequency oscillation signals is then drawn.

[0023] Calculate the area enclosed by the coordinate axes from the reference inflection point to the end region in the scatter plot of each group of low-frequency oscillation signals to obtain the area of ​​each group of discharge current from the l-th group to the (n+l-th)-th group of discharge current.

[0024] The average area of ​​the discharge currents from group l to group n+l-1 is taken as the average area of ​​the background data.

[0025] Optionally, the formula for calculating the steady-state deviation rate is as follows:

[0026]

[0027] In the formula, ε l This represents the steady-state deviation rate of the (n+l)th discharge current group. s is the mean area of ​​the background data corresponding to the (n+l)th group of discharge currents. n+l Let be the area of ​​the (n+l)th group of discharge currents.

[0028] Optionally, determining the maximum steady-state deviation rate during the period from the first time to the second time as the deviation rate threshold specifically includes:

[0029] Obtain the maximum steady-state deviation rate ε during the period from the first time point to the second time point. max ;

[0030] At the maximum steady-state deviation rate ε max Add a 5% error margin to the base, and ε max +5% as the threshold.

[0031] Optionally, the frequency range of the low-frequency oscillation signal is 10kHz to 100kHz.

[0032] A Hall thruster on-orbit operation status monitoring system includes:

[0033] The acquisition module is used to acquire n sets of discharge currents on the anode side of the Hall thruster using non-invasive methods during the period from the stable start of Hall thruster operation to the first time.

[0034] The filtering module is used to filter the discharge current using fast Fourier transform to obtain n sets of low-frequency oscillation signals;

[0035] The plotting module is used to divide each group of low-frequency oscillation signals into multiple intervals, with the median discharge current of each interval as the independent variable and the number of discrete points of the low-frequency oscillation signal in each interval as the dependent variable, and plot a scatter plot of each group of low-frequency oscillation signals.

[0036] The inflection point determination module is used to determine the inflection point of each scatter plot and use the mean of the n inflection points as the benchmark inflection point.

[0037] The area calculation module is used to take the first n groups of discharge currents collected after the first time as background data, and calculate the area enclosed by the coordinate axis from the reference inflection point to the end region in the scatter plot of each group of discharge currents in the real-time discharge current group and the background data, respectively, to obtain the area of ​​the real-time discharge current group and the average area of ​​the background data.

[0038] The steady-state deviation rate determination module is used to determine the steady-state deviation rate of the real-time discharge current group based on the area of ​​the real-time discharge current group and the average area of ​​the background data.

[0039] The deviation rate threshold determination module is used to determine the maximum steady-state deviation rate during the period from the first time to the second time as the deviation rate threshold; the second time is greater than the first time.

[0040] The determination module is used to compare the steady-state deviation rate of the real-time discharge current group after the second time with the deviation rate threshold. If it is greater than the deviation rate threshold, it is determined that there is a perturbation in the Hall thruster.

[0041] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the aforementioned method for monitoring the on-orbit operating status of a Hall thruster.

[0042] A computer-readable storage medium having a computer program stored thereon, which, when executed, implements the aforementioned method for monitoring the on-orbit operating status of a Hall thruster.

[0043] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0044] This invention discloses a method and system for monitoring the on-orbit operating status of a Hall thruster. It utilizes a non-invasive method to acquire the discharge current on the anode side of the Hall thruster, filters the discharge current to obtain a low-frequency oscillation signal, determines the reference inflection point of the scatter plot based on the low-frequency oscillation signal, and then uses the reference inflection point to determine the deviation rate threshold. When the steady-state deviation rate exceeds the deviation rate threshold, it is determined that a perturbation exists in the Hall thruster. This invention utilizes the easily measurable low-frequency oscillation of the discharge current during Hall thruster operation as a status indicator to achieve on-orbit monitoring of the thruster's operating status. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 A flowchart illustrating a method for monitoring the on-orbit operating status of a Hall thruster, provided in an embodiment of the present invention;

[0047] Figure 2 A schematic diagram of a method for monitoring the on-orbit operation status of a Hall thruster provided in an embodiment of the present invention;

[0048] Figure 3 A scatter plot provided for an embodiment of the present invention;

[0049] Figure 4 This is a comparison chart of the scatter plot of the original data of low-frequency oscillation of discharge current and the polynomial fitting data provided in the embodiments of the present invention. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] The purpose of this invention is to provide a method and system for monitoring the on-orbit operation status of a Hall thruster. The method utilizes the low-frequency oscillation of the discharge current, which is easily measurable on-orbit during the operation of the Hall thruster, as a status indicator to achieve on-orbit monitoring of the thruster's operating status.

[0052] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] This invention provides a method for monitoring the on-orbit operating status of a Hall thruster, such as... Figure 1 As shown, it includes the following steps:

[0054] Step S1: During the period from the stable start of Hall thruster operation to the first time, n sets of discharge currents on the anode side of Hall thruster are collected using non-invasive methods.

[0055] After the Hall thruster has been running for about 3 hours and its operation has stabilized, the discharge current I on the anode side of the thruster is collected using an oscilloscope or waveform recorder. Multiple sets of discharge currents are collected sequentially from the time the thruster stabilizes until the first time interval.

[0056] Step S2: The discharge current is filtered using Fast Fourier Transform to obtain n sets of low-frequency oscillation signals.

[0057] The discharge current I is filtered by using Fast Fourier Transform (FFT) to remove the main DC component determined by the power supply properties and high-frequency oscillations, while retaining the low-frequency oscillation signal of 10kHz to 100kHz.

[0058] Step S3: Divide each group of low-frequency oscillation signals into multiple intervals, using the median discharge current of each interval as the independent variable and the number of discrete points of the low-frequency oscillation signal in each interval as the dependent variable, and draw a scatter plot of each group of low-frequency oscillation signals.

[0059] Statistical analysis was performed on the time domain of the low-frequency oscillation signal of the discharge current. Each group of oscillation signals was divided into 90 small intervals, and the number of discrete signal points corresponding to each small interval was calculated. The median discharge current I between each small interval was used as the criterion. i The independent variable is N, which corresponds to the number of scatter points in the interval. i Draw a scatter plot with the variable as the dependent variable. Figure 3 This is a schematic diagram of a scatter plot. The scatter plot shows that on the crest side of the discharge current oscillation (i.e., the region where the filtered discharge current is greater than 0), the number of scatter points first decreases sharply with increasing crest height, and then decreases again at a crest height of I. c The rate of decline in the vicinity slows down or even reaches an inflection point C.

[0060] Step S4: Determine the inflection point of each scatter plot and use the mean of the n inflection points as the baseline inflection point.

[0061] According to the mathematical definition of an inflection point, if a function is twice differentiable, and its second derivative is zero at a certain point with opposite signs at both ends, then that point is an inflection point. Therefore, the inflection point C is calculated as follows:

[0062] 1) For crest divergence I j (I i Polynomial fitting is performed on x ≥ 0 to obtain the fitting function f(x);

[0063] 2) Calculate the second derivative of the fitted function f(x) and find the values ​​of the second derivative at the corresponding points. The inflection point C here is not an inflection point in the strict mathematical sense, therefore its second derivative is not required to be strictly equal to 0; it only needs to satisfy... and That's all.

[0064] 3) Using the n sets of data collected within 60 hours after the thruster has stabilized as a benchmark, the inflection point x of the n sets of data is calculated using the method in (2). k And calculate their mean. by This serves as the benchmark inflection point.

[0065] Step S5: Take the first n groups of discharge currents collected after the first time as background data, and calculate the area enclosed by the coordinate axis from the reference inflection point to the end region in the scatter plot of each group of discharge currents in the real-time discharge current group and the background data respectively, to obtain the area of ​​the real-time discharge current group and the average area of ​​the background data.

[0066] For example, step S5 is implemented as follows:

[0067] The discharge current of the (n+l)th group is acquired in real time after the first time, and the discharge current of the (n+l-1)th group to the discharge current of the (n+l-1)th group is used as background data.

[0068] Fast Fourier Transform is used to filter the discharge currents from the l-th group to the (n+l-th)-th group to obtain the low-frequency oscillation signal of each group of discharge currents.

[0069] The low-frequency oscillation signal of each group of discharge currents is divided into multiple intervals. The median discharge current of each interval is the independent variable, and the number of discrete points of the low-frequency oscillation signal in each interval is the dependent variable. A scatter plot of each group of low-frequency oscillation signals is then drawn.

[0070] Calculate the area enclosed by the coordinate axes from the reference inflection point to the end region in the scatter plot of each group of low-frequency oscillation signals to obtain the area of ​​each group of discharge currents from the l-th group to the (n+l-th)-th group; using the reference inflection point x c As the starting point of the integration interval, the fitting function f(x) for each set of data lies within its respective interval [x...]. c ,x 90 Integrate over the given area to obtain the area s. k ;

[0071] The average area of ​​the discharge currents from group l to group n+l-1 is taken as the average area of ​​the background data.

[0072] Step S6: Determine the steady-state deviation rate of the real-time discharge current group based on the area of ​​the real-time discharge current group and the average area of ​​the background data.

[0073] In one example, the formula for calculating the steady-state deviation rate is:

[0074]

[0075] In the formula, ε l This represents the steady-state deviation rate of the (n+l)th discharge current group. s is the mean area of ​​the background data corresponding to the (n+l)th group of discharge currents. n+l Let be the area of ​​the (n+l)th group of discharge currents.

[0076] Taking the time from the stable start of Hall thruster operation to the first time as 60 hours as an example, the calculation process of steps S5 to S6 is listed.

[0077] Given n sets of data from the previous 60 hours as background data, calculate the area s. k mean After 60 hours, collect a set of data n+1, and first calculate the area s according to step (3). n+1 and the mean By subtraction, the steady-state oscillation deviation can be obtained. Divide it by the mean Obtain steady-state deviation rate When collecting n+2 sets of data, use sets 2 to n+1 of data to construct new n sets of background data, and calculate the new mean. and the new steady-state deviation rate And so on, until the (n+l)th set of data, the mean of the n sets of background data... steady-state deviation rate As shown in Table 1 below.

[0078] Table 1 Calculation results of maximum steady-state deviation rate

[0079]

[0080]

[0081] Step S7: Determine the maximum steady-state deviation rate during the period from the first time to the second time as the deviation rate threshold. The second time is greater than the first time.

[0082] Assuming that m sets of data are added between the 60th and 75th hours of thruster operation, i.e., l = m, according to Table 1, by comparing ε1 to ε m To obtain the maximum steady-state deviation rate ε max And at the maximum steady-state deviation rate ε max Add a 5% error margin to the base, i.e., ε max +5% is the deviation rate threshold.

[0083] Step S8: Compare the steady-state deviation rate of the real-time discharge current group after the second time with the deviation rate threshold. If it is greater than the deviation rate threshold, it is determined that there is a perturbation in the Hall thruster.

[0084] For the newly acquired discharge current group after 75 hours, if the obtained steady-state deviation rate ε l >ε max +5% indicates a minor disturbance in the system, triggering an alarm.

[0085] This invention proposes a Hall thruster operating status indicator based on the statistical characteristics of low-frequency oscillation time-scale signals. This method can monitor the discharge signal during the thruster's operation in real time and provide timely feedback when external input signals are disturbed.

[0086] This invention analyzes and processes the discharge current signal of the Hall thruster, which is monitored and acquired by an oscilloscope (or waveform recorder), enabling on-orbit monitoring of the thruster's operating status. It can relatively accurately distinguish between steady-state and disturbance conditions, and issue early warnings when the thruster's input parameters or environmental disturbances are affected. Ground monitoring personnel can then adjust the thruster's operating parameters in real time based on these warnings to prevent irreversible damage. This invention provides technical support for the large-scale application of Hall thrusters.

[0087] Taking a 600W Hall thruster under the following conditions: anode voltage 300V, anode flow rate 25.1sccm, cathode flow rate 1.5sccm, internal excitation current 2.5A, external excitation current 2A, and 488 sets of discharge current data (including 480 sets of steady-state data and 8 sets of disturbance data (anode voltage, anode flow rate, and cathode flow rate)) collected within 82 hours after stable operation, as an example.

[0088] (1) After the Hall thruster has been running for about 3 hours and the thruster has been running stably, the discharge current I on the anode side of the thruster is collected using a waveform recorder. The discharge current I is filtered by Fast Fourier Transform (FFT) to remove the main DC components and high-frequency oscillations determined by the power supply properties, and retain the low-frequency oscillation signal of 10kHz to 100kHz.

[0089] (2) Statistical analysis was performed on the time domain of the low-frequency oscillation signal of the discharge current. Each group of oscillation signals was divided into 90 small intervals, and the number of discrete signal points corresponding to each small interval was calculated. The median discharge current I between each small interval was used as the basis for the analysis. i The independent variable is N, which corresponds to the number of scatter points in the interval. i Plot a scatter plot with I as the dependent variable. The scatter plot shows that, at the peak of the discharge current oscillation (i.e., the region where the filtered discharge current is greater than 0), the number of scatter points first decreases sharply with increasing peak height, and then decreases again at peak height I. c The rate of descent slows down or even reaches an inflection point C. According to the mathematical definition of an inflection point, if a function is twice differentiable, and the second derivative at a certain point is zero, with the second derivatives at both ends having opposite signs, then that point is an inflection point. Therefore, the inflection point C is calculated as follows:

[0090] 1) For crest divergence I j (I i Polynomial fitting is performed on x ≥ 0 to obtain the fitting function f(x); Figure 4 The comparison between the raw scatter plot of the low-frequency oscillation data of the discharge current and the polynomial fitted data is shown.

[0091] 2) Calculate the second derivative of the fitted function f(x) and find the values ​​of the second derivative at the corresponding points. The inflection point C here is not an inflection point in the strict mathematical sense, therefore its second derivative is not required to be strictly equal to 0; it only needs to satisfy... and That's all.

[0092] 3) Using 360 sets of data collected within 60 hours after the thruster has been running stably as a benchmark, the inflection point x of the 360 ​​sets of data is calculated using the method in (2). k And calculate their mean. get As the benchmark inflection point, such as Figure 3 As shown.

[0093] (3) After determining the baseline inflection point in step (2), calculate the area s enclosed by the coordinate axes and the region from the inflection point to the end of each data set, i.e., the area s within the interval [x c ,x 90 The area s of each group is obtained by integrating the fitted function f(x). k .

[0094] (4) Using the 360 ​​sets of data from the previous 60 hours as background data, calculate the area s. k mean After 60 hours, collect a set of data n+1, and first calculate the area s according to step (3). n+1 and the mean By subtraction, the steady-state oscillation deviation can be obtained. Divide it by the mean Obtain steady-state deviation rate When collecting n+2 sets of data, use sets 2 to n+1 of data to construct new n sets of background data, and calculate the new mean. and the new steady-state deviation rate And so on, until the (n+l)th set of data, the mean of the n sets of background data... steady-state deviation rate As shown in Table 1.

[0095] From the 60th to the 75th hour of thruster operation, 90 new data sets were added, i.e., l=90. According to Table 1, by comparing ε1 to ε 90 To obtain the maximum steady-state deviation rate ε max =19.96%. And at the maximum steady-state deviation rate ε max Add a 5% error margin to the base, i.e., ε max +5% = 24.96% is the disturbance discrimination threshold.

[0096] (5) For the 38 sets of data newly acquired after 75 hours, calculate the area s according to steps (3) and (4). k and the real-time updated mean Find the difference, then divide it by the mean. Obtain steady-state deviation rate And use the steady-state deviation rate ε l The results are shown in Table 2 below, compared with the disturbance discrimination threshold of 24.96%.

[0097] Table 2. Operational effect of disturbance indicator

[0098]

[0099] As shown in Table 2, this invention does not produce false alarms during steady-state operation. When the anode voltage, anode flow rate, and cathode flow rate change, the invention accurately identifies disturbances except when the anode voltage decreases by 2V (i.e., the voltage drops by only 0.7% in a relatively stable operating condition). Furthermore, this invention utilizes the easily measurable low-frequency oscillation of the discharge current during Hall thruster operation as a status indicator. Data acquisition is easy, facilitating on-orbit monitoring and providing technical support for the large-scale application of Hall thrusters.

[0100] The present invention also provides an on-orbit operating status monitoring system for a Hall thruster, comprising:

[0101] The acquisition module is used to acquire n sets of discharge currents on the anode side of the Hall thruster using non-invasive methods during the period from the stable start of Hall thruster operation to the first time.

[0102] The filtering module is used to filter the discharge current using fast Fourier transform to obtain n sets of low-frequency oscillation signals;

[0103] The plotting module is used to divide each group of low-frequency oscillation signals into multiple intervals, with the median discharge current of each interval as the independent variable and the number of discrete points of the low-frequency oscillation signal in each interval as the dependent variable, and plot a scatter plot of each group of low-frequency oscillation signals.

[0104] The inflection point determination module is used to determine the inflection point of each scatter plot and use the mean of the n inflection points as the benchmark inflection point.

[0105] The area calculation module is used to take the first n groups of discharge currents collected after the first time as background data, and calculate the area enclosed by the coordinate axis from the reference inflection point to the end region in the scatter plot of each group of discharge currents in the real-time discharge current group and the background data, respectively, to obtain the area of ​​the real-time discharge current group and the average area of ​​the background data.

[0106] The steady-state deviation rate determination module is used to determine the steady-state deviation rate of the real-time discharge current group based on the area of ​​the real-time discharge current group and the average area of ​​the background data.

[0107] The deviation rate threshold determination module is used to determine the maximum steady-state deviation rate during the period from the first time to the second time as the deviation rate threshold; the second time is greater than the first time.

[0108] The determination module is used to compare the steady-state deviation rate of the real-time discharge current group after the second time with the deviation rate threshold. If it is greater than the deviation rate threshold, it is determined that there is a perturbation in the Hall thruster.

[0109] The Hall thruster on-orbit operation status monitoring system provided in this embodiment of the invention has a similar working principle and beneficial effects to the Hall thruster on-orbit operation status monitoring method described in the above embodiments, so it will not be described in detail here. For details, please refer to the introduction of the above method embodiments.

[0110] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the aforementioned method for monitoring the on-orbit operating status of a Hall thruster.

[0111] Furthermore, when the computer program in the aforementioned memory is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.

[0112] Furthermore, the present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed, implements the aforementioned method for monitoring the on-orbit operating status of a Hall thruster.

[0113] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0114] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, 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 the present invention.

Claims

1. A method for monitoring the on-orbit operating status of a Hall thruster, characterized in that, include: During the period from the stable start of Hall thruster operation to the first time, n sets of discharge currents on the anode side of Hall thruster are collected using non-invasive methods. The discharge current is filtered using a fast Fourier transform to obtain n sets of low-frequency oscillation signals; Each group of low-frequency oscillation signals is divided into multiple intervals. The median discharge current of each interval is the independent variable, and the number of discrete points of the low-frequency oscillation signal in each interval is the dependent variable. A scatter plot of each group of low-frequency oscillation signals is then drawn. Determine the inflection point of each scatter plot, and use the mean of the n inflection points as the baseline inflection point; Using the average of n inflection points as the baseline inflection point, including: using the formula Calculate n inflection points mean ,by As the benchmark inflection point; The first n sets of discharge currents collected after the first time point are used as background data. In the scatter plots of each discharge current set in both the real-time discharge current set and the background data, the area enclosed by the coordinate axes from the reference inflection point to the end region is calculated to obtain the area of ​​the real-time discharge current set and the mean area of ​​the background data. The calculation of the area enclosed by the coordinate axes from the reference inflection point to the end region includes: calculating the area enclosed by the coordinate axes from the reference inflection point to the end region in the scatter plot of each low-frequency oscillation signal to obtain the mean area of ​​the first n sets of discharge currents. Group discharge current up to the first The area of ​​each discharge current group in the discharge current group; with reference inflection point. As the starting point of the integration interval, the fitting function is used for each set of data. In their respective intervals Integrate the above to obtain the area. ; Indicates the end region; The steady-state deviation rate of the real-time discharge current group is determined based on the area of ​​the real-time discharge current group and the average area of ​​the background data. The maximum steady-state deviation rate during the period from the first time to the second time is determined as the deviation rate threshold; the second time is greater than the first time. Compare the steady-state deviation rate of the real-time discharge current group after the second time with the deviation rate threshold. If it is greater than the deviation rate threshold, it is determined that there is a perturbation in the Hall thruster.

2. The method for monitoring the on-orbit operation status of a Hall thruster according to claim 1, characterized in that, Determining the inflection point of each scatter plot specifically includes: The portion of the scatter plot with a discharge current greater than zero is fitted with a polynomial to obtain the fitting function. Calculate the second derivative of the fitted function, and simultaneously satisfy... and The point is determined as the inflection point; among them, For point In the fitting function The value of the second derivative in the second derivative.

3. The method for monitoring the on-orbit operating status of a Hall thruster according to claim 1, characterized in that, The method involves using the first n sets of discharge currents collected after the first time as background data, and calculating the area enclosed by the coordinate axes from the reference inflection point to the end region in the scatter plots of each set of discharge currents in the real-time discharge current group and the background data, respectively, to obtain the area of ​​the real-time discharge current group and the mean area of ​​the background data. Specifically, this includes: The first time after real-time collection Group discharge current, and the first Group discharge current up to the first The discharge current of the group is used as background data; Using Fast Fourier Transform to the first Group discharge current up to the first The discharge currents of each group are filtered to obtain a low-frequency oscillation signal for each group of discharge currents. The low-frequency oscillation signal of each group of discharge currents is divided into multiple intervals. The median discharge current of each interval is the independent variable, and the number of discrete points of the low-frequency oscillation signal in each interval is the dependent variable. A scatter plot of each group of low-frequency oscillation signals is then drawn. Calculate the area enclosed by the coordinate axes from the reference inflection point to the end region in the scatter plot of each group of low-frequency oscillation signals to obtain the area of ​​the first group. Group discharge current up to the first The area of ​​each discharge current group in the discharge current group; For the first Group discharge current up to the first The average area of ​​the discharge current in the group is used as the average area of ​​the background data.

4. The method for monitoring the on-orbit operating status of a Hall thruster according to claim 1, characterized in that, The formula for calculating the steady-state deviation rate is as follows: In the formula, For the first Steady-state deviation rate of the discharge current group. For the first The mean area of ​​the background data corresponding to the discharge current of the group. For the first The area of ​​the discharge current group.

5. The method for monitoring the on-orbit operating status of a Hall thruster according to claim 1, characterized in that, The step of determining the maximum steady-state deviation rate during the period from the first time to the second time as the deviation rate threshold specifically includes: Obtain the maximum steady-state deviation rate during the period from the first time point to the second time point. ; At the maximum steady-state deviation rate Add a 5% error margin to the base, As a threshold.

6. The method for monitoring the on-orbit operating status of a Hall thruster according to claim 1, characterized in that, The frequency range of the low-frequency oscillation signal is 10kHz to 100kHz.

7. A Hall thruster on-orbit operation status monitoring system, characterized in that, include: The acquisition module is used to acquire n sets of discharge currents on the anode side of the Hall thruster using non-invasive methods during the period from the stable start of Hall thruster operation to the first time. The filtering module is used to filter the discharge current using fast Fourier transform to obtain n sets of low-frequency oscillation signals; The plotting module is used to divide each group of low-frequency oscillation signals into multiple intervals, with the median discharge current of each interval as the independent variable and the number of discrete points of the low-frequency oscillation signal in each interval as the dependent variable, and plot a scatter plot of each group of low-frequency oscillation signals. The inflection point determination module is used to determine the inflection point of each scatter plot and use the mean of the n inflection points as the benchmark inflection point. Using the average of n inflection points as the baseline inflection point, including: using the formula Calculate n inflection points mean ,by As the benchmark inflection point; The area calculation module is used to take the first n groups of discharge currents collected after the first time as background data, and calculate the area enclosed by the coordinate axis from the reference inflection point to the end region in the scatter plots of each group of discharge currents in the real-time discharge current group and the background data, respectively, to obtain the area of ​​the real-time discharge current group and the average area of ​​the background data; the calculation of the area enclosed by the coordinate axis from the reference inflection point to the end region includes: calculating the area enclosed by the coordinate axis from the reference inflection point to the end region in the scatter plot of each group of low-frequency oscillation signals to obtain the area of ​​the first n groups of discharge currents collected after the first time. Group discharge current up to the first The area of ​​each discharge current group in the discharge current group; with reference inflection point. As the starting point of the integration interval, the fitting function is used for each set of data. In their respective intervals Integrate the above to obtain the area. ; Indicates the end region; The steady-state deviation rate determination module is used to determine the steady-state deviation rate of the real-time discharge current group based on the area of ​​the real-time discharge current group and the average area of ​​the background data. The deviation rate threshold determination module is used to determine the maximum steady-state deviation rate during the period from the first time to the second time as the deviation rate threshold; the second time is greater than the first time. The determination module is used to compare the steady-state deviation rate of the real-time discharge current group after the second time with the deviation rate threshold. If it is greater than the deviation rate threshold, it is determined that there is a perturbation in the Hall thruster.

8. An electronic device, characterized in that, The method includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the Hall thruster on-orbit operation status monitoring method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, It stores a computer program, which, when executed, implements the Hall thruster on-orbit operation status monitoring method as described in any one of claims 1 to 6.

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