Spacecraft energy system fault simulation method based on stand-alone circuit-level modeling

Abstract

The invention discloses a spacecraft energy system fault simulation method based on stand-alone circuit-level modeling, and belongs to the field of spacecraft system simulation. The method comprises the following steps: firstly, establishing a spacecraft energy circuit system capable of comprehensively covering the state of a power supply network of an energy system, and carrying out hierarchical setting on fault types possibly occurring in the spacecraft energy circuit system; based on a spacecraft energy circuit system model, different fault data are injected at different levels, the fault data comprise fault types, set parameter variation ranges, fault occurrence moments and fault stop moments, then fault simulation setting and simulation operation parameter setting are carried out, analogue simulation is carried out, and a simulation result is obtained. The granularity of the model goes deep into a stand-alone circuit level, and perfect energy fault mode recognition and influence analysis are carried out based on the model, so that the model is supported to carry out perfect work such as reliability design, fault plan and reconstruction program design, and the long-term in-orbit flight safety of a spacecraft is ensured.

Description

Technical Field

[0001] The invention relates to a spacecraft energy system fault simulation method based on single-machine circuit-level modeling, and belongs to the field of spacecraft system simulation. Background Art

[0002] The energy system is an important part of the spacecraft. In recent years, satellites at home and abroad have repeatedly suffered from energy system-related failures, which has caused the decline or even complete loss of the entire satellite function. The reason is that the identification of energy failures is insufficient and the impact analysis is not comprehensive. Therefore, there are problems on orbit that exceed the designer's cognition and the failure response measures are ineffective or insufficient. On the one hand, this is because the power of spacecraft has gradually increased in recent years, and the energy system itself has become more complex. On the other hand, it is also because the overall personnel lack effective methods for energy failure simulation. Only through traditional circuit design analysis or simple system-level modeling, it is no longer possible to effectively analyze and identify system failures. There is no overall design method to accurately analyze the impact of various failures on the system. According to statistics, 40% of the failures in on-orbit spacecraft are related to the power supply and distribution system, which fully illustrates the difficulty of fault mode identification and risk control of spacecraft energy systems, which cannot be simply solved by paper analysis. In addition, the complexity and life index requirements of current spacecraft are getting higher and higher, which poses a more severe test for the reliability of spacecraft power supply and distribution.

[0003] Large-scale manned spacecraft use 100V high-power multi-bus energy systems, with power generation and consumption reaching more than 30KW, and more than 1,000 power-consuming equipment. The energy system has the characteristics of high power, high load, high voltage and long life. The system has formed a complex structure of multiple bus cross-networking and a difficult management strategy of multi-mode flexible scheduling. The number of system working modes and interface states has increased significantly, and there are complex processes such as on-orbit assembly and reconstruction. At the same time, the energy system needs to be assembled in steps on-orbit and have the ability to reconstruct the system topology. Faced with such complex energy system technology and mission function requirements, the traditional method of designers conducting local analysis and then conducting system-level fault analysis is no longer adaptable. It is necessary to improve the ability to identify and analyze energy faults through effective analysis methods.

[0004] Scholars in the fields of electrical design and aviation design have conducted energy-related modeling and simulation, but have rarely involved fault simulation. Scholars in the ground power grid and ship fields have conducted some research, but they are generally focused on large system-level faults, and there is little research on the actual work of circuit-level support engineering. In addition, the architecture, functions, and design parameters of energy systems in other fields are significantly different from those of aerospace energy systems, and cannot be used in spacecraft simulation. Spacecraft system simulation is still in its infancy, with few public documents, and almost no literature on energy fault simulation. Summary of the invention

[0005] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and propose a spacecraft energy system fault simulation method based on single-machine circuit level modeling. By modeling and simulating the spacecraft energy system at the single-machine circuit level, the faults at various levels of the energy system are simulated based on system indicator requirements.

[0006] The technical solution of the present invention is:

[0007] A method for simulating faults in a spacecraft energy system based on single-machine circuit-level modeling, comprising:

[0008] Establish a spacecraft energy system circuit model, including multiple single-cabin energy system models and visiting aircraft models, each of which is a hierarchical model;

[0009] Layered settings for possible failure types of spacecraft energy systems;

[0010] Based on the circuit model of the spacecraft energy system, different fault data are injected at different levels. The fault data includes the fault type, the range of setting parameter changes, the time when the fault occurs and when it stops. Then the fault simulation setting and simulation operation parameter setting are performed, and simulation is carried out to obtain the simulation results.

[0011] Furthermore, the single-cabin energy system circuit model and the visiting aircraft model are both hierarchical models, and the hierarchy from bottom to top includes component model, single machine model, subsystem model, subsystem model, and system model;

[0012] The design requirements for component models are as follows: resistors, capacitors, inductors, transformers, diodes and power devices use real circuit device models, and signal device models use digital equivalent models;

[0013] The design requirements for the stand-alone model are as follows: the power topology adopts the real stand-alone structure design, the stand-alone information interface adopts the digital equivalent model, and the external power supply and internal power transmission adopt the circuit device model;

[0014] The subsystem model is composed of individual machine models and cables;

[0015] The subsystem model is composed of each subsystem model and cables;

[0016] The system model consists of subsystem models and cables.

[0017] Furthermore, the parameter design requirements for each level of model are:

[0018] Model voltage simulation range: The voltage adaptation range is [0, U], where U is greater than the theoretical maximum range of the bus voltage fluctuation of the spacecraft, and a 20% margin is reserved;

[0019] Model current simulation range: The current adaptation range is [0, U / R], where R is the theoretical minimum resistance between the power bus and the system ground;

[0020] Model impedance simulation range: The model impedance range is [0, R'], R' is the open circuit impedance, greater than 500MΩ;

[0021] Fault temperature simulation range: The model temperature range is [T 1 ,T 2 ], T 1 T is the lowest temperature that a device or component may experience on orbit. 2 The maximum temperature that a device or component may experience in orbit;

[0022] Fault time simulation range: The fault time selection range is [0,t 2 ], t 2 Maximum time to work for system tasks;

[0023] Simulation step length at fault moment: The simulation step length shall not exceed 1 / 10 of the highest control frequency of the system.

[0024] Furthermore, the possible faults of the spacecraft energy system are hierarchically set up, from bottom to top:

[0025] Component functional failure and parameter drift: Component functional failure includes functional failure of the components used, including device circuit function failure, single particle effect, device pin short circuit, pin / contact open circuit; parameter drift includes resistance, capacitance, control coefficient parameter drift of the components used, including time drift, temperature drift and unexpected drift;

[0026] Single machine failure: covers possible failures determined by analysis of model busbar control, battery, power distribution equipment, and load equipment. Possible failures include voltage control exceeding the rated range, output power reduction, power distribution switch state jump, load short circuit, and cable open and short circuit;

[0027] System faults: including possible faults determined by model bus analysis, including single bus power failure, instantaneous power failure, short circuit, and bus voltage exceeding the rated value;

[0028] Combined faults: The above three types of faults are combined and set according to the system working mode and equipment action.

[0029] Furthermore, for various levels of failures that may occur in the spacecraft energy system, if the fault simulation involves gradually changing parameters, the normal value of the parameter is set first, and the parameter change amount is set during the simulation operation. The parameter change amount is a continuous value set according to the characteristics of the parameter, and changes regularly with the simulation time during the fault simulation.

[0030] Furthermore, for various levels of failures that may occur in the spacecraft energy system, if the fault simulation involves step-type parameters, first set the normal value of the parameter, and set the parameter change amount during the simulation operation. The parameter change amount is an intermittent value set according to the characteristics of the parameter. During the fault simulation process, a step change is performed at a specified time or multiple times.

[0031] Furthermore, for the pin / contact open circuit in the component function failure, the resistance between the fault points is set to be greater than 100MΩ; for the device pin short circuit in the component function failure, the resistance between the fault points is set to 0-1Ω.

[0032] Furthermore, parameter drift is simulated: the value of the electrical characteristic of the device is set to change according to the device manual, deviating from the nominal value or rated value.

[0033] Furthermore, a fault simulation is set, and the simulation process includes:

[0034] S1: Import the fault data to be simulated;

[0035] S2: Perform steady-state simulation and calculate initial parameters;

[0036] S3: call in transient simulation, modify transient simulation calculation parameters, and select the waveform list to be recorded in transient simulation;

[0037] S4: Calling in the measurement tool, and selecting the variables to be measured from the simulated system model;

[0038] S5: Calling in the threshold test tool, selecting a variable from the measured variables as a judgment variable for whether a fault occurs, and writing the fault judgment condition;

[0039] S6: Call in the waveform tool, add one or more variables, and add the system waveform that needs to be observed when a fault occurs.

[0040] Furthermore, simulation operation parameters are set to achieve convergence of the simulation; for an energy system with more than 20,000 devices and more than 30,000 system parameters, the simulation operation parameters are set as follows:

[0041] Steady-state simulation calculation settings: sampling point density is 1, time resolution is 1p, maximum AD change range is 3, and Newton step density is 1;

[0042] Transient simulation calculation settings: simulation step size is 1ms, simulation progress monitoring is 100, run steady-state simulation, truncation error is allowed to be 0.0005, truncation error type is transient, sampling point density is 1, time resolution is 100p, zero delay iteration is 100, variable error is allowed to be 1u, algorithm is Newton-Raphson method, Newton step density is 1, maximum Newton iteration is 100, target iteration is 15.

[0043] The advantages of the present invention compared with the prior art are:

[0044] (1) The present invention establishes for the first time a technical method for carrying out energy failure simulation at the spacecraft system level, which provides a powerful technical means for improving the overall reliability design of energy systems by the overall design department.

[0045] (2) In the energy system fault simulation, the advanced black-and-white box hybrid modeling technology is generally used to solve the scale control problem of large system models and the coordination problem of simulation accuracy. The modeling and testing method of hierarchical modeling and step-by-step testing is adopted. On the basis of normal mode simulation, a simulation method from component parameters to system-level faults is proposed for the first time, solving the problem of fault simulation implementation path. The simulation technology process is proposed for the operation of complex system models, and the simulation setting method of each link is refined; finally, for the problem of simulation convergence, the specific method of selecting simulation operation algorithms and setting operation parameters is given. All technologies are highly innovative and advanced, and can be used to guide the development of related technologies.

[0046] (3) The present invention establishes a system-level digital model that can comprehensively cover the power supply network status of the energy system. The model granularity needs to be deep into the single-machine circuit level. Based on this model, comprehensive energy fault pattern identification and impact analysis can be carried out. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0048] Figure 1 This is a flow chart of fault simulation analysis in accordance with an embodiment of the present invention;

[0049] Figure 2 Schematic diagram of the circuit model of the energy system according to the embodiment of the present invention, (a) is the circuit model of the core cabin in the energy system, (b) is the circuit model of the experimental cabin in the energy system;

[0050] Figure 3 A schematic diagram of the relationship between the energy system circuit model and the injected fault according to an embodiment of the present invention;

[0051] Figure 4 This is a simulation result diagram of the sunny area of ​​an embodiment of the present invention;

[0052] Figure 5 This is a simulation result diagram of the shadow area of ​​an embodiment of the present invention. DETAILED DESCRIPTION

[0053] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0054] The present invention proposes a method for simulating spacecraft energy system faults based on single-machine circuit-level modeling. First, a system-level digital model that can comprehensively cover the power supply network status of the energy system is established. The model granularity needs to be in-depth to the single-machine circuit level. Based on this model, comprehensive energy fault pattern recognition and impact analysis are carried out to support the model to carry out comprehensive reliability design and fault prevention plans, reconstruction program design, etc., to ensure the long-term on-orbit flight safety of the spacecraft.

[0055] S1: System Modeling

[0056] To carry out fault simulation, we must first establish an energy system circuit model that supports fault simulation. Different from general conventional simulation models, fault simulation models require higher computing support capabilities and wider variable support capabilities. Therefore, it is necessary to design the type, granularity and combination method of the basic model used to establish the system model. Among them, the key parameters of the basic model need to be clarified to support the fault injection setting.

[0057] 1) Model design method

[0058] According to the design of spacecraft energy system, a model basic device library or stand-alone circuit is formed through black box modeling, white box modeling, black and white box hybrid modeling and other means, and then tested. For the power circuit part, since its subtle characteristics directly affect the power supply control characteristics, a white box model based on power components and wires is adopted. For the information processing part such as command control, a black box model with equivalent function is adopted to control the system scale.

[0059] Based on the basic device library, a stand-alone model is built according to the design plan and technical requirements, and then tested and modified;

[0060] On the basis of the single machine model, a subsystem model is built according to the subsystem solution, and then tested and modified;

[0061] Based on the subsystem model, a well-structured single-cabin model and combined energy system model are built according to the system solution;

[0062] Formulate modeling and testing requirements for subsystem models / stand-alone models, and simultaneously collect subsystem or stand-alone simulation models. After passing the test, access the system model, replace the original subsystem or stand-alone model, and improve the system model.

[0063] For the components selected for the power circuit, the device library model corresponding to the actual circuit specifications should be used. For those whose performance cannot be completely matched, a custom device library should be built by fitting the interface characteristic curve.

[0064] 2) Model Architecture

[0065] The energy system model is constructed and designed according to the design status of the spacecraft energy system. It consists of a multi-cabin energy system model and a visiting vehicle model. The single-cabin energy system model or the visiting vehicle model includes three parts: primary power supply model, power distribution model and load model.

[0066] The whole system model consists of: A-cabin single-cabin system-level model, B-cabin single-cabin system-level model, C-cabin single-cabin system-level model, and multi-cabin combination connection model.

[0067] The model building hierarchy from bottom to top includes:

[0068] a) Component model: Power devices such as resistors, capacitors, inductors, transformers, and diodes use real circuit device models, and signal device models use digital equivalent models;

[0069] b) Single-machine model: The power topology adopts the real single-machine structure design, the single-machine information interface adopts the digital equivalent model, and the external power supply and internal power transmission adopt the circuit device model;

[0070] c) Subsystem model, consisting of individual machines and cables;

[0071] d) Subsystem model, consisting of various subsystems and cables;

[0072] e) Single cabin energy system model, consisting of subsystem models and cables;

[0073] f) The combined energy system model consists of various compartments and cables.

[0074] 3) Model parameter design method

[0075] Model voltage simulation range: The voltage adaptation range should be [0, U], where U should be larger than the theoretical maximum range of the spacecraft bus voltage fluctuation and a 20% margin should be reserved;

[0076] Model current simulation range: The current adaptation range should be [0, U / R], where R is the theoretical minimum resistance between the power bus and the system ground;

[0077] Model impedance simulation range: The model impedance range should be [0, R'], where R' is the open circuit impedance, which should generally be greater than 500MΩ;

[0078] Fault temperature simulation range: The model temperature range should be [T 1,T 2 ], T 1 T is the lowest temperature that a device or component may experience on orbit. 2 The maximum temperature that a device or component may experience in orbit;

[0079] Fault time simulation range: The fault time selection range should be [0,t 2 ], t 2 Maximum time to work for system tasks;

[0080] Simulation step length at fault time: The simulation step length a should be related to the highest control frequency f of the system, satisfying a≤0.1f. The simulation step length should be shortened as much as possible under the condition that the system computing power can support it. For variable step length analysis, the maximum step length should be used to meet the above requirements.

[0081] Fault parameter simulation range: The device or equipment parameter range should be [b 1 ,b 2 ], b 1 is the theoretical minimum value of the parameter, b 2 is the theoretical maximum value of the parameter.

[0082] S2: Fault simulation method

[0083] 1) Fault hierarchical setting

[0084] For complex energy systems, from key components to complex stand-alone equipment, their own failures or parameter deviations may cause system failures. Therefore, the problems that cause system failures are divided into multiple levels, from bottom to top:

[0085] A. Component functional failure / parameter drift: It should include the functional failure of the components used, including device circuit function failure, single particle effect, device pin short circuit, pin / contact open circuit, etc.; It should include the parameter drift of the resistance, capacitance, control coefficient, etc. of the components used, including time drift, temperature drift and unexpected drift, etc.;

[0086] B Single machine failure: It should include possible failures determined by analysis of model busbar control, batteries, distribution equipment, and load equipment, including voltage control exceeding the rated range, output power reduction, distribution switch state jump, load short circuit, cable open circuit / short circuit, etc. It is also necessary to simulate single battery pack failures, etc.

[0087] C System failure: should include possible failures determined by model bus analysis, including single bus power failure, instantaneous power failure, short circuit, bus voltage exceeding rated value, etc.;

[0088] D. Combination fault: A system fault is also often caused by a key parameter drift condition, superimposed with a minor problem or short-term event. For example, the bus voltage may drop for a short time due to a large load startup, and high-power motor equipment may fail to start successfully under low bus voltage conditions. Therefore, the above three types of faults can be combined according to the system working mode and equipment action, which helps to discover potential system faults.

[0089] The corresponding relationship between faults at different levels and energy system models at different levels is as follows: Figure 3 As shown, Type A faults mainly occur in component models, Type B faults mainly occur in single-machine models, and Type C faults mainly occur in subsystem models, subsystem models, and single-cabin energy system models.

[0090] 2) Fault simulation settings for gradual variable

[0091] For parameters with gradual changes, such as operating temperature t, capacitor internal resistance r, inductor value, op amp gain k, etc., for the selected parameters of the specified device or equipment, first set them to the normal value x, and set the parameter change Δx(t) during the simulation run. Δx(t) should be a continuous value set according to the characteristics of the variable, and change regularly with the simulation time t during the fault simulation process. Typical changes include linear increase, linear decrease, and periodic repeated changes.

[0092] 3) Fault simulation settings for step variables

[0093] For parameters with step changes, such as load power p, single unit output power p', bus voltage u, etc., for the selected parameters of the specified device or equipment, first set them to the normal value y, and set the parameter change Δy(t) during the simulation operation. Δy(t) should be an intermittent value set according to the characteristics of the variable. During the fault simulation process, a step change is performed at a specified time or multiple times. Typical changes include a single step increase, a single step decrease, and periodic repeated changes.

[0094] 4) Simulation settings for severe power supply faults such as open circuit and short circuit

[0095] Severe power supply faults such as open circuit and short circuit are special cases of impedance step change. For open circuit faults, the impedance parameters of the specified components and cables are set to r x =100MΩ parameter simulates open circuit; for short circuit fault, extract two nodes j in the circuit where short circuit may occur 1 and j 2 , an adjustable impedance model z is connected between the two nodes. In the normal state, it is in the high-impedance state z=100MΩ. When simulating a short circuit, the impedance step is reduced to z<1Ω. The specific value is selected according to the theoretical model and can reach the mΩ level.

[0096] 5)Combination parameter change fault setting

[0097] For some complex system failures, the failures are often caused by the simultaneous occurrence of two or more deviations. It is often difficult to conduct intuitive analysis of the effects caused by changes in different combinations of variables. Therefore, dedicated algorithm support is needed for these failures.

[0098] The algorithm for changing the combination variables that may cause system failure is set. The parameter traversal analysis method and Monte Carlo analysis method are used to obtain the system status under n groups of parameter combinations. Combined with the system indicator requirements, the actual possible failure combinations of the system are screened out.

[0099] S3: Fault simulation process and key simulation parameter settings

[0100] Fault simulation analysis process Figure 1 As shown, based on the establishment of the fault model, the fault simulation is carried out according to the following steps:

[0101] 1) Start simulation according to the fault condition and system model status;

[0102] 2) Perform fault injection settings and clearly define the fault location, mechanism, time and other information, as follows:

[0103] 2.1) First, determine the model level, model name, and parameter name of the fault injection according to the purpose of fault simulation;

[0104] 2.2) Confirm the fault type, parameter variation range, fault occurrence time, and stop time of the fault injection model;

[0105] 2.3) Confirm the combination of faults, single fault or combination of faults;

[0106] 2.4) Create a new fault injection setting, select the corresponding fault injection model in the system model, select the range or parameters of the fault injection, and complete the corresponding setting of the fault according to the above situation;

[0107] 2.5) Save the fault injection settings and name them according to the fault situation.

[0108] 3) Perform fault simulation settings, clarify the run call instance, simulation operation parameters, observed waveforms and judgment conditions, etc.

[0109] In order to ensure that the operation can be solved, the Newton-Raphson method is used for calculation. This method is an iterative method for numerical root finding of nonlinear equations. It has the advantage of fast convergence and is conducive to ensuring the timeliness of simulation calculations. In practical applications, attention should be paid to the setting of various matching parameters.

[0110] It is necessary to effectively set the operator, operation parameters, iteration method and number of times to ensure that the large-scale model can converge and give effective calculation results. This parameter method is suitable for energy system models based on circuits, and the scale can support large-scale model operations with more than 20,000 devices (more than 3,000 nonlinear devices), more than 30,000 system variables, and simulation time of more than 1 second.

[0111] A) Steady-state simulation calculation settings:

[0112] Sampling point density: 1

[0113] Debug setting: no

[0114] Time resolution: 1p

[0115] Maximum AD change range: 3

[0116] Algorithm stepping: yes

[0117] Newton step density: 1

[0118] B) Transient simulation calculation settings:

[0119] Simulation duration: 1s / set as needed

[0120] Simulation step: 1ms

[0121] Simulation progress monitoring: 100 items

[0122] Run steady-state simulation: Yes

[0123] Signal list: select only the signals of interest to reduce computational overhead

[0124] Truncation error allowed: 0.0005

[0125] Truncation Error Type: Transient

[0126] Sampling point density: 1

[0127] Time resolution: 100p

[0128] Zero Delay Iterations: 100

[0129] Variable error allowance: 1u

[0130] Algorithm: Newton-Raphson method

[0131] Newton step density: 1

[0132] Max Newton Iterations: 100

[0133] Target iterations: 15

[0134] The process of setting up fault simulation is:

[0135] 3.1) Call in the fault injection settings to be simulated;

[0136] 3.2) Perform steady-state simulation and calculate initial parameters;

[0137] 3.3) Call in transient simulation, modify transient simulation calculation parameters, and select the waveform list to be recorded in transient simulation;

[0138] 3.4) Call in the measurement tool and select the variables to be measured from the simulated system model;

[0139] 3.5) Call the threshold test tool, select the variable to judge whether a fault has occurred from the measured variables, and write the fault judgment condition;

[0140] 3.6) Call in the waveform tool, add one or more variables, and add the system waveform that needs to be observed when the fault occurs;

[0141] 3.7) Call up the canvas tool; add one or more waveforms, and add the system waveforms that need to be observed when the fault occurs;

[0142] 3.8) Save the results.

[0143] 4) Run the fault simulation and observe the operation status. If there is an operation error, jump to step 2 and step 3 to adjust the simulation algorithm and step size setting. The process of fault simulation operation is:

[0144] 4.1) Start the simulation tool in the simulation operation interface;

[0145] 4.2) Select the saved instance for fault simulation;

[0146] 4.3) Click to run the simulation;

[0147] 4.4) Observe the fault simulation running in the simulation result window. If an error occurs, correct the setting or model according to the error. Repeat the above steps until the simulation progress bar reaches 100%;

[0148] 5) After the simulation operation is completed, analyze the results. If there are any additions or adjustments, jump to step 2.

[0149] 5.1) System Fault Simulation Criteria

[0150] According to the system design and indicator system, the criteria for system failure are identified, and the analysis method of failure results is studied. The following functions and performance indicators are monitored and monitored. If the function decreases or is lost in the simulation, or the parameters exceed the limit, it is considered that a system-level failure has occurred. Including: bus voltage steady-state range, power generation output power, bus instantaneous voltage change, bus ripple (ripple frequency, ripple voltage peak-peak value), transient response characteristics of load step, energy storage battery charging and discharging function, battery discharge depth (DOD), distribution network dispatching function, bus distribution power, bus switch control, load switch control, shunt regulation ability, overvoltage and overcurrent protection function, cable network signal transmission, distribution function and distribution power, load power characteristics, distribution overcurrent protection characteristics, cable voltage drop, secondary voltage range, system conversion and transmission efficiency loss.

[0151] 5.2) Fault simulation results and impact analysis

[0152] The contents of fault simulation result analysis are as follows:

[0153] a) Select the result display tool of the simulation software;

[0154] b) Check all the waveform change curves observed separately to find the waveform changes when the fault occurs and stops;

[0155] c) Call the analysis and waveform measurement tools to measure the maximum, minimum, value at a certain moment, average value and other data in the waveform and analyze the data;

[0156] d) Open the simulation report, expand the fault judgment variables, check the conditions that are met and those that are not met, and analyze the data.

[0157] e) Make judgments item by item based on system function and performance requirements and identify fault conditions that do not meet the requirements.

[0158] 6) After the simulation is completed, export the simulation results.

[0159] In view of the fault simulation requirements of a large-scale combined spacecraft energy system, the specific implementation method is introduced as follows:

[0160] S1: System Modeling

[0161] According to the system topology of the combined spacecraft, a circuit model is established, the power circuit of the power supply and distribution equipment is modeled based on circuit devices, and the control and signal parts are equivalently modeled. The load is divided into constant power load, motor load and constant resistance load according to the type. Figure 2 As shown, (a) is the circuit model of the core module in the energy system, and (b) is the circuit model of the experimental module in the energy system. Based on the two single-module models, a combined energy system model is formed according to the on-orbit networking power supply status.

[0162] Before conducting fault simulation, the accuracy of the normal working condition of the system model must be tested and corrected until the accuracy requirements are met, which serves as the basis for fault simulation. Based on the energy system status and energy system design requirements, the energy system fault simulation modeling and testing of the combined spacecraft was carried out, and the conclusions are as follows:

[0163] 1) A primary power supply model was established based on the power supply scheme, and the primary power supply interface characteristics were tested. The simulation results showed that the primary power supply model met the technical requirements;

[0164] 2) A power distribution model was established based on the power distribution scheme, and the interface characteristics of the power distribution system were tested. The simulation results showed that the power distribution model met the technical requirements;

[0165] 3) A load model was established based on the load power consumption state, and the load interface characteristics were tested. The simulation results showed that the load model met the technical requirements;

[0166] 4) A simulation model of the combined energy system was constructed and typical operating conditions were tested. The results showed that the topology, function and performance indicators reflected by the model established by the parent institute met the technical requirements of the energy system, and the steady-state simulation accuracy of key parameters was better than ±5%.

[0167] S2: Fault simulation setting method

[0168] 1) Connection fault simulation: open circuit of pins, short circuit between pins, virtual connection of connectors, virtual short, open circuit of lines (pad vias fall off, printed tape cracks), virtual short (overlap) between lines, etc. Among them:

[0169] Open pins, loose connectors, open circuits (pad vias fall off, printed tape cracks): The resistance between fault points is set to be greater than 100MΩ;

[0170] Short circuit between pins, virtual short circuit, virtual short circuit between lines (overlap): The resistance between fault points is set to 0~1Ω, and the specific value is set according to the short circuit situation.

[0171] 2) Simulation of device functional failures: device over-voltage, over-current, over-heating, parameter drift, parameter symbol, performance degradation, etc.

[0172] Device over-stress (overvoltage, overcurrent, overheating): Set the voltage and current values ​​between the specified pin of the device and the ground, and between the pins of the device to exceed the normal operating range; set the operating temperature of the device to exceed the normal operating temperature.

[0173] Parameter drift, parameter deviation, performance degradation, etc.: The electrical characteristics of the device set according to the device manual change in value, deviating from the nominal value or rated value, such as reduced operating efficiency, increased device thermal resistance, etc.

[0174] 3) Definition of permanent fault and transient fault: a permanent fault is a fault that cannot be recovered after failure, and a transient fault is a fault that can be recovered after a short period of time after failure;

[0175] Permanent fault: Set the fault change to a single time, for example, set the abnormal fault in which the signal between two points changes from normal connection to continuous disconnection.

[0176] Transient fault: Set a fault that lasts for a certain period of time. For example, set an abnormal fault in which the signal between two points changes from normal connection to disconnection for 1 second, and then returns to normal connection after 1 second.

[0177] 4) Selection of the fault occurrence time: Faults can be injected at any time during the simulation: according to the spacecraft program time or flight status, the fault is set to occur at a specified time during the simulation, rather than just setting the fault before the simulation starts.

[0178] 5) Custom concurrent faults: For particularly complex spacecraft energy system faults, separate faults are set independently, and then two or more faults are injected into the system at the same time. Designers define different fault groups as needed and evaluate multiple groups of fault modes;

[0179] 6) Simulation of faults at different levels: For device failures, single machine failures or subsystem failures, simulation is performed by setting faults in the circuit level model where the respective faults occur.

[0180] S3: Typical fault simulation process

[0181] Taking the power FMEA parameter drift fault as an example, the setting method of fault simulation is explained. Its type belongs to the fault of continuous change drift of key parameters of a single machine causing the system bus voltage to change. The power subsystem bus filter realizes the integrated conditioning and output of the power control MEA signal, and serves as the feedback control signal of the power subsystem to control the bus voltage. It is a key signal of the power subsystem. At the same time, since this signal has a direct impact on the bus voltage, it is related to system safety. The specific process is as follows:

[0182] First, a simulation model of the spacecraft power system is established, and the electrical models of each power supply device are established based on power devices and control circuits, including panels, shunt regulators, charge and discharge controllers, bus filters, power supply controllers, etc.

[0183] According to the power supply failure mode analysis, the subsystem has a failure mode in which a single abnormality occurs in the three MEA input signals and then the signal is cut off. This fault case simulates the busbar status before the MEA signal is abnormal but no action is taken.

[0184] 1) Initial state setting

[0185] Sunny area: In the initial setting, the power subsystem is in normal working condition, the panels in the sunny area are generating electricity normally, the shunt regulator is working normally, the load is in the rated power state, and the bus voltage is controlled normally at 105V.

[0186] Shaded area: In the initial setting, the power subsystem is in normal working condition, the windsurfing board does not generate electricity, the shunt regulator does not work, the charge and discharge regulator is in the discharge working state, the load is in the rated power state, and the bus voltage is normally controlled at 101V.

[0187] The MEA signal is in a normal conversion state, the signal conditioning proportional gain is 1, and has no effect on the signal value.

[0188] 2) Fault injection settings

[0189] The simulation conditioning coefficient changes to four value states of 0.2, 0.5, 2, and 4 respectively. The four values ​​are injected in sequence at different times (5s, 9s, 13s, and 17s) to observe the states of key parameters of the power subsystem.

[0190] 3) Simulation results:

[0191] The simulation results of the sunny area are as follows Figure 4 As shown in Table 1, in Table 1, "Fail" means that the simulation result exceeds the allowed threshold range. In the Yangzhao area, when the four parameter change failures occur, the bus voltage of one parameter group will be greater than 111V, but the bus voltage will not be lower than 100V. The normal bus voltage that exceeds the construction specification index requirement is less than the 106V requirement.

[0192] Table 1 Simulation results of sunny area

[0193]

[0194] The simulation results of the shadow area are as follows Figure 5 As shown in Table 2, in Table 2, "Fail" means that the simulation result exceeds the allowed threshold range. In the shaded area, when the four parameter change failures occur, the bus voltage of one parameter group will be less than 100V, but the bus voltage will not exceed 106V. The bus voltage that is lower than the index requirement is greater than the 100V requirement.

[0195] Table 2 Simulation results of shadow area

[0196]

[0197] Analyzing the simulation data, if the parameters change as caused by the fault injected this time, the bus voltage will exceed the normal range in both the sunny and shaded areas. Although it does not exceed the safe voltage range of 80-120V, it can be seen that the parameters of the MEA conditioning circuit have a very direct impact on the bus voltage. The current design of a single chip to implement the conditioning parameters has the risk of causing abnormal bus fluctuations under fault conditions.

[0198] According to the above fault simulation results, the spacecraft model needs to focus on reviewing and confirming the circuit design reliability of the MEA signal of the power subsystem, and avoid bus voltage fluctuations caused by abnormalities in a single conditioning circuit by adding redundant design.

[0199] The present invention proposes a method for simulating the fault of a spacecraft energy system based on single-machine circuit-level modeling, realizes the active identification of complex energy system faults based on system patterns, and performs impact analysis based on the modified circuit model, which strongly supports the overall designers in identifying energy system fault patterns and formulating countermeasures. The implementation of simulation solves the problem of the difficulty in identifying some complex faults, and on the other hand, it can perform impact analysis on faults that are difficult to simulate in the system, greatly improving the verification coverage, reducing a large amount of engineering development and implementation costs, and achieving significant benefits.

[0200] The modeling method has good reference significance and can provide support for simulation modeling with other models; the fault simulation process has good reference significance, and the application in the model and the process of fault simulation itself can be directly applied to other models. At the same time, due to the use of modular modeling ideas, the various models invented are suitable for energy modeling and fault simulation of other spacecraft using approximate circuits, which can directly support designers in the design of energy systems, and have good economic benefits and promotion prospects.

[0201] Through the fault simulation of the combined energy system, a set of system models was formed: the scale reached 38,000 variables, 26,000 devices, and 4,000 nonlinear devices. It can correctly reflect the topology, function, and key electrical performance of the energy system. The indicators meet the technical requirements of the energy system. The steady-state simulation accuracy of key parameters is better than ±5%. The model can be used as a model to simulate the characteristics of the energy system.

[0202] Typical cases were selected to carry out simulation analysis on system-level, single-machine-level, and component-level failures of the energy system. This solved the problem of lack of digital means for fault design and analysis in the development of prototypes, provided a way for system failure analysis and simulation, solved the problem of inability to carry out serious failure verification in system-level testing, and avoided the huge amount of manpower and material resources consumed by special physical test verification, greatly improving the design and development efficiency.

[0203] After a busbar power failure occurred on a certain model in orbit, the system did not have the ability to conduct system-level simulation verification on the ground. In order to verify the busbar power failure phenomenon and mechanism after the power supply array channel device failure in the problem zeroing analysis, the subsystem was organized to carry out special simulation tests on related fault circuits. The device allocation, test preparation and data analysis took 3 days, with 3 direct test participants and 9 man-days. Through simulation analysis, based on the system model, only 1 designer was required to set up the fault condition and simulate the fault, which took 3 hours and did not require any additional funding support. While solving the lack of means, work efficiency was greatly improved.

[0204] The above-described embodiments are only preferred specific implementations of the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for simulating faults in a spacecraft energy system based on single-machine circuit-level modeling, characterized in that: include: Establishing a spacecraft energy system circuit model, including multiple single-cabin energy system circuit models and a visiting vehicle circuit model, each of which is a hierarchical model; Layered settings for possible failure types of spacecraft energy systems; Based on the circuit model of the spacecraft energy system, different fault data are injected at different levels. The fault data include fault type, setting parameter variation range, fault occurrence time and stop time. Fault simulation settings and simulation operation parameter settings are performed, and simulation results are obtained.

2. The method for simulating a fault in a spacecraft energy system based on single-machine circuit-level modeling according to claim 1 is characterized in that: The spacecraft energy system circuit model covers the power supply network status of the energy system. The single-cabin energy system circuit model and the visiting aircraft model are both hierarchical models, which include component model, single-machine model, subsystem model, subsystem model, and system model from bottom to top. The design requirements for component models are as follows: resistors, capacitors, inductors, transformers, diodes and power devices use real circuit device models, and signal device models use digital equivalent models; The design requirements for the stand-alone model are as follows: the power topology adopts the real stand-alone structure design, the stand-alone information interface adopts the digital equivalent model, and the external power supply and internal power transmission adopt the circuit device model; The subsystem model is composed of individual machine models and cables; The subsystem model is composed of each subsystem model and cables; The system model consists of subsystem models and cables.

3. The method for simulating a fault in a spacecraft energy system based on single-machine circuit-level modeling according to claim 2 is characterized in that: The parameter design requirements for each level of model are: Model voltage simulation range: The voltage adaptation range is [0, U], where U is greater than the theoretical maximum range of the bus voltage fluctuation of the spacecraft, and a 20% margin is reserved; Model current simulation range: The current adaptation range is [0, U / R], where R is the theoretical minimum resistance between the power bus and the system ground; Model impedance simulation range: The model impedance range is [0, R'], R' is the open circuit impedance, greater than 500MΩ; Fault temperature simulation range: The model temperature range is [T1, T2], where T1 is the lowest temperature that the device or component may experience on track, and T2 is the highest temperature that the device or component may experience on track; Fault time simulation range: The selection range of fault time is [0, t2], where t2 is the maximum working time of the system task; Simulation step length at fault moment: The simulation step length shall not exceed 1 / 10 of the highest control frequency of the system.

4. The method for simulating a fault in a spacecraft energy system based on single-machine circuit-level modeling according to claim 1, characterized in that: The possible faults of the spacecraft energy system are hierarchically set, from bottom to top: Component functional failure and parameter drift: Component functional failure includes functional failure of the components used, including device circuit function failure, single particle effect, device pin short circuit, and pin contact open circuit; parameter drift includes resistance, capacitance, and control coefficient parameter drift of the components used, including time drift, temperature drift, and unexpected drift; Single machine failure: covers possible failures determined by analysis of model busbar control, battery, power distribution equipment, and load equipment. Possible failures include voltage control exceeding the rated range, output power reduction, power distribution switch state jump, load short circuit, and cable open and short circuit; System faults: including possible faults determined by model bus analysis, including single bus power failure, instantaneous power failure, short circuit, and bus voltage exceeding the rated value; Combined faults: The above three types of faults are combined and set according to the system working mode and equipment action.

5. The method for simulating a fault in a spacecraft energy system based on single-machine circuit-level modeling according to claim 4 is characterized in that: For various levels of failures that may occur in the spacecraft energy system, if the fault simulation involves gradually changing parameters, first set the normal value of the parameter, and set the parameter change during the simulation. The parameter change is a continuous value set according to the characteristics of the parameter, and changes regularly with the simulation time during the fault simulation.

6. The method for simulating a fault in a spacecraft energy system based on single-machine circuit-level modeling according to claim 4 is characterized in that: For various levels of failures that may occur in the spacecraft energy system, if the fault simulation involves step-type parameters, first set the normal value of the parameter, and set the parameter change amount during the simulation. The parameter change amount is an intermittent value set according to the characteristics of the parameter. During the fault simulation process, a step change is performed at a specified time or multiple times.

7. The method for simulating a fault in a spacecraft energy system based on single-machine circuit-level modeling according to claim 4 is characterized in that: For the simulation of open circuit of pin contacts in component functional failure, the resistance between fault points is set to be greater than 100MΩ; for the simulation of short circuit of device pins in component functional failure, the resistance between fault points is set to 0-1Ω.

8. The method for simulating a fault in a spacecraft energy system based on single-machine circuit-level modeling according to claim 4 is characterized in that: Simulate parameter drift: Set the value of the device's electrical characteristics according to the device manual to change, deviating from the nominal value or rated value.

9. The method for simulating a fault in a spacecraft energy system based on single-machine circuit-level modeling according to claim 1, characterized in that: Perform fault simulation settings. The simulation process includes: S1: Import the fault data to be simulated; S2: Perform steady-state simulation and calculate initial parameters; S3: call in transient simulation, modify transient simulation calculation parameters, and select the waveform list to be recorded in transient simulation; S4: Calling in the measurement tool, and selecting the variables to be measured from the simulated system model; S5: Calling in the threshold test tool, selecting a variable from the measured variables as a judgment variable for whether a fault occurs, and writing the fault judgment condition; S6: Call up the waveform tool, add variables, and add the system waveform that needs to be observed when a fault occurs.

10. The method for simulating a fault of a spacecraft energy system based on single-machine circuit-level modeling according to claim 7, characterized in that: Set the simulation operation parameters to achieve convergence of the simulation; for an energy system with more than 20,000 devices and more than 30,000 system parameters, the simulation operation parameters are set as follows: Steady-state simulation calculation settings: sampling point density is 1, time resolution is 1p, maximum AD change range is 3, and Newton step density is 1; Transient simulation calculation settings: simulation step size is 1ms, simulation progress monitoring is 100, run steady-state simulation, truncation error is allowed to be 0.0005, truncation error type is transient, sampling point density is 1, time resolution is 100p, zero delay iteration is 100, variable error is allowed to be 1u, algorithm is Newton-Raphson method, Newton step density is 1, maximum Newton iteration is 100, target iteration is 15.

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