Safety simulation analysis method and system for hydrogen hybrid aircraft power system

Abstract

The invention discloses a hydrogen hybrid aircraft power system safety simulation analysis method and system, and belongs to the technical field of aviation system safety. The method comprises the steps that a hydrogen hybrid aircraft power system is decomposed into a plurality of subsystems, the state and state transition conditions of each subsystem are determined, and the state transition conditions of each subsystem are determined; and outputs generated by the subsystems in different states. According to the state of each subsystem, the state transition condition and the output generated by each subsystem in different states, a finite-state machine of each subsystem is constructed, and the finite-state machines of each subsystem are connected in series and in parallel to construct a finite-state machine network; setting initial conditions, fault injection conditions, simulation time spans, power requirements and flight mission profiles of the subsystems, executing simulation, acquiring simulation results, and determining state changes of the subsystems in the hydrogen hybrid power aircraft power system and matching conditions of output power and required power of the subsystems. The method can effectively improve the accuracy of safety assessment.

Description

Technical Field

[0001] The present invention relates to the field of aviation system safety technology, and more specifically to a safety simulation analysis method and system for a hydrogen hybrid power aircraft power system. Background Art

[0002] With the development of the aviation industry and the improvement of environmental protection requirements, hydrogen hybrid aircraft as a new type of aircraft has received widespread attention. According to statistics, the transportation sector accounts for 25% of the total carbon dioxide emissions generated by energy consumption, of which the aviation industry accounts for about 11% of the 25% transportation sector. With the improvement of battery and motor technology, the electrification of aircraft propulsion systems has the potential to reduce energy consumption and emissions of transport aircraft. Therefore, the development of advanced hybrid system architectures to improve energy efficiency can effectively reduce carbon emissions, and the research and development of hydrogen hybrid aircraft has become a hot topic in the aviation field. However, the high degree of integration of hydrogen hybrid aircraft power systems and the complexity of the combination of software and hardware have posed new challenges to safety analysis.

[0003] Traditional safety analysis methods mainly include Fault Tree Analysis (FTA) and Markov chain, but both face some limitations in showing the continuous change mechanism of complex systems. This method assumes that the probability of state transition is constant, which is inconsistent with the actual dynamic characteristics of many failure modes in hydrogen hybrid systems. Among them, FTA analyzes potential fault paths in the system by constructing logic gates and events. Although FTA provides a structured method for identifying and evaluating system failures, FTA mainly focuses on the static fault logic of the system and is difficult to capture the dynamic behavior and complex interactions of hydrogen hybrid aircraft power systems in actual operation. Markov chains are usually used to describe the random transition process of system states. Although they have advantages in analyzing the long-term behavior of the system and predicting the degradation of system performance, when applied to hydrogen hybrid aircraft power systems, Markov chains are usually unable to effectively simulate non-random state changes caused by external events or operator decisions.

[0004] In summary, due to the high degree of integration of hydrogen hybrid aircraft power systems and the complexity of the combination of software and hardware, the traditional Markov chain method assumes that the probability of state transition is constant, which is inconsistent with the actual dynamic characteristics of many fault modes in hydrogen hybrid systems, affecting the accuracy of the analysis results. Summary of the invention

[0005] In response to the problems existing in the above-mentioned fields, the present invention proposes a hydrogen hybrid aircraft power system safety simulation analysis method and system, which decomposes the hydrogen hybrid aircraft power system to be simulated into multiple subsystems, extracts the functions of each subsystem, determines the state and state transition conditions of each subsystem, and the outputs generated by each subsystem in different states, and constructs a finite state machine network, which can effectively improve the accuracy of safety assessment.

[0006] In order to solve the above technical problems, the present invention discloses a safety simulation analysis method for a hydrogen hybrid aircraft power system, comprising the following steps:

[0007] Decompose the hydrogen hybrid aircraft power system to be simulated into multiple subsystems, extract the functions of each subsystem, determine the state and state transition conditions of each subsystem, and the output generated by each subsystem in different states;

[0008] According to the state of each subsystem, the state transition conditions and the outputs generated by each subsystem in different states, the finite state machine of each subsystem is constructed, and the finite state machines of each subsystem are connected in series and in parallel to construct a finite state machine network; according to the constructed finite state machine network, the initial conditions, fault injection conditions, simulation time span, power requirements and flight mission profile of each subsystem are set, the simulation is executed, and the simulation results are obtained;

[0009] Based on the simulation results, the changes in the states of each subsystem in the hydrogen hybrid aircraft power system and the matching of the output power of each subsystem with the required power are determined.

[0010] Preferably, the determining of the state and state transition condition of each subsystem, and the output generated by each subsystem in different states specifically includes:

[0011] By analyzing the working mechanism of the hydrogen hybrid aircraft power system to be simulated, the subsystems in the hydrogen hybrid aircraft power system to be simulated are identified, including the hydrogen storage system, hydrogen internal combustion engine, generator, battery and electric motor, and the functions of each subsystem are extracted;

[0012] Based on the extracted functions of each subsystem, define the state and state transition conditions of each subsystem, as well as the outputs generated by each subsystem under normal and abnormal working conditions.

[0013] Preferably, the finite state machine network is constructed by connecting the finite state machines of each subsystem in series and in parallel, comprising the following steps:

[0014] By defining the states of each subsystem under normal and abnormal working conditions;

[0015] The state and state transition conditions of each subsystem are modeled using a finite state machine, wherein the finite state machine of each subsystem includes a state set, an event set, a transition function, an initial state, and a terminal state;

[0016] A finite state machine network is constructed, and the finite state machines of each subsystem are connected through the network. Various variables in the hydrogen hybrid aircraft power system to be simulated, including power and hydrogen supply, are used as the input and output of the state machines of each subsystem in the finite state machine network. Hazardous events or "a variable exceeding a certain threshold" are regarded as state transfer conditions. The state machines of each subsystem are integrated in series and parallel to form a finite state machine network to simulate the interactions and dependencies between the subsystems.

[0017] Preferably, the obtaining of simulation results comprises the following steps:

[0018] Obtaining the initial conditions of the simulation, including the status of each subsystem and the overall working mode of the hydrogen hybrid aircraft power system to be simulated;

[0019] Obtain fault injection conditions, including hydrogen leakage and battery thermal runaway failure modes, and set specific parameters for each failure mode, including leakage rate and thermal runaway temperature threshold;

[0020] Get the simulated time span and mission profile, including power requirements for takeoff, cruise, and landing;

[0021] The constructed finite state machine network is executed through simulation software, and the matching degree between the power output by the finite state machine network and the required input power is compared;

[0022] Record and analyze the performance parameters of the hydrogen hybrid aircraft power system to be simulated under fault conditions, including power output, battery temperature, hydrogen internal combustion engine temperature, battery remaining power and hydrogen remaining amount;

[0023] The simulation is performed, including the states of each subsystem under normal and abnormal working conditions. For each fault condition under abnormal working conditions, the entire process of the hydrogen hybrid aircraft power system to be simulated from the occurrence of the fault to the termination state is recorded.

[0024] Preferably, the determining of the change in the state of each subsystem in the power system of the hydrogen hybrid aircraft and the matching of the output power of each subsystem with the required power specifically includes:

[0025] Based on the simulation results, the fault propagation path is identified to determine the potential risk points in the hydrogen hybrid aircraft power system to be simulated, and then the impact of the potential risk points on flight safety is analyzed. The impact of the fault on the performance of the hydrogen hybrid aircraft power system and the fault propagation mechanism are analyzed, and the analysis results of the impact of the fault on the performance of the hydrogen hybrid aircraft power system and the fault propagation mechanism are obtained.

[0026] Preferably, the analysis of the impact of faults on the performance of the hydrogen hybrid aircraft power system and the fault propagation mechanism specifically includes:

[0027] Based on the recorded and analyzed performance parameters of the hydrogen hybrid aircraft power system to be simulated under fault conditions, the power system response and safety of the hydrogen hybrid aircraft power system to be simulated during take-off, cruising and landing phases under normal and abnormal working conditions are evaluated.

[0028] Preferably, the method further includes proposing suggestions for improving the safety of the hydrogen hybrid aircraft power system to be simulated based on the simulation results, the suggestions including improving the design of the hydrogen storage system, enhancing the thermal management of the battery, and optimizing the fault detection and response mechanism.

[0029] Preferably, it also includes a hydrogen hybrid aircraft power system safety simulation analysis system, including:

[0030] The system decomposition module is used to decompose the hydrogen hybrid aircraft power system to be simulated into multiple subsystems, and to determine the state and state transition conditions of each subsystem, as well as the output generated by each subsystem in different states by extracting the functions of each subsystem;

[0031] The simulation module is used to construct the finite state machine of each subsystem according to the state of each subsystem, the state transition condition and the output generated by each subsystem in different states, and construct a finite state machine network by connecting the finite state machines of each subsystem in series and in parallel; according to the constructed finite state machine network, set the initial conditions, fault injection conditions, simulation time span, power demand and flight mission profile of each subsystem, execute simulation, and obtain simulation results;

[0032] The safety assessment module is used to determine the changes in the status of each subsystem in the hydrogen hybrid aircraft power system and the matching of the output power of each subsystem with the required power based on the simulation results.

[0033] Preferably, a computer device is also included, the computer device comprising a memory and a processor, the memory storing a computer program, and when the computer program is executed by the processor, the processor executes the following steps:

[0034] Decompose the hydrogen hybrid aircraft power system to be simulated into multiple subsystems, extract the functions of each subsystem, determine the state and state transition conditions of each subsystem, and the output generated by each subsystem in different states;

[0035] According to the state of each subsystem, the state transition conditions and the outputs generated by each subsystem in different states, the finite state machine of each subsystem is constructed, and the finite state machines of each subsystem are connected in series and in parallel to construct a finite state machine network; according to the constructed finite state machine network, the initial conditions, fault injection conditions, simulation time span, power requirements and flight mission profile of each subsystem are set, the simulation is executed, and the simulation results are obtained;

[0036] Based on the simulation results, the changes in the states of each subsystem in the hydrogen hybrid aircraft power system and the matching of the output power of each subsystem with the required power are determined.

[0037] Preferably, it further comprises a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor executes the following steps:

[0038] Decompose the hydrogen hybrid aircraft power system to be simulated into multiple subsystems, extract the functions of each subsystem, determine the state and state transition conditions of each subsystem, and the output generated by each subsystem in different states;

[0039] According to the state of each subsystem, the state transition conditions and the outputs generated by each subsystem in different states, the finite state machine of each subsystem is constructed, and the finite state machines of each subsystem are connected in series and in parallel to construct a finite state machine network; according to the constructed finite state machine network, the initial conditions, fault injection conditions, simulation time span, power requirements and flight mission profile of each subsystem are set, the simulation is executed, and the simulation results are obtained;

[0040] Based on the simulation results, the changes in the states of each subsystem in the hydrogen hybrid aircraft power system and the matching of the output power of each subsystem with the required power are determined.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention proposes a safety simulation and analysis method for a hydrogen hybrid aircraft power system. The method decomposes the hydrogen hybrid aircraft power system into multiple subsystems, extracts key physical variables of each subsystem, determines the state and state transition conditions of each subsystem, and the output generated by each subsystem in different states, and constructs a simulation model of a finite state machine network based on a finite state machine to simulate and analyze the safety of the hydrogen hybrid aircraft power system under normal operation and failure conditions. The method can determine the state and state transition conditions of each subsystem, and the output generated by each subsystem in different states, which is more in line with the actual dynamic characteristics of many failure modes in the hydrogen hybrid system, and breaks through the technical defect of the traditional Markov chain method that assumes that the probability of state transition is constant. By setting the initial conditions, fault injection conditions, simulation time span, power requirements and flight mission profile of each subsystem, executing the simulation, determining the changes in the states of each subsystem in the hydrogen hybrid aircraft power system, and the matching of the output power of each subsystem with the required power, the performance of the hydrogen hybrid aircraft power system under normal operation and potential fault conditions is deeply analyzed to improve the safety of the aircraft power system. The simulation can model the propagation process of multiple faults, quantitatively analyze the impact of key failure modes such as hydrogen leakage and battery thermal runaway on system safety, support system safety optimization and improvement, improve the accuracy of the analysis results, and provide decision support for the safety design analysis of hydrogen hybrid aircraft power systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A flow chart of the safety simulation analysis method for the hydrogen hybrid aircraft power system proposed by the present invention;

[0044] Figure 2 A schematic diagram of the state machines and variable interaction relationships of each subsystem provided in an embodiment of the present invention;

[0045] Figure 3 The change process of the output power in the power system of a hydrogen hybrid aircraft under a hydrogen leakage accident provided by an embodiment of the present invention;

[0046] Figure 4 The change process of the battery temperature and the internal combustion engine temperature in the power system of a hydrogen hybrid aircraft under a hydrogen leakage accident provided by an embodiment of the present invention;

[0047] Figure 5 The change process of the state of charge (SOC) of the battery in the power system of a hydrogen hybrid aircraft in the event of a hydrogen leakage accident provided by an embodiment of the present invention;

[0048] Figure 6 The embodiment of the present invention provides a change process of the remaining amount of available hydrogen in the hydrogen storage tank of a hydrogen hybrid aircraft power system in the event of a hydrogen leakage accident. DETAILED DESCRIPTION

[0049] The following will be combined with the attached embodiment of the present invention Figure 1-Figure 6 , the technical solutions in the embodiments of the present invention are clearly and completely described. It should be understood that the terms described in the present invention are only used to describe specific implementation methods and are not used to limit the present invention.

[0050] like Figure 1 As shown, the present invention proposes a safety simulation analysis method for a hydrogen hybrid aircraft power system, comprising the following steps:

[0051] S1: Decompose the hydrogen hybrid aircraft power system to be simulated into multiple subsystems, extract the functions of each subsystem, determine the state and state transition conditions of each subsystem, and the output generated by each subsystem in different states;

[0052] S2: According to the state of each subsystem, the state transition conditions and the output of each subsystem in different states, the finite state machine of each subsystem is constructed, and the finite state machines of each subsystem are connected in series and in parallel to construct a finite state machine network; according to the constructed finite state machine network, the initial conditions, fault injection conditions and simulation time span of each subsystem are set, and the simulation is executed by setting the power demand and the flight mission profile to obtain the simulation results;

[0053] S3: Based on the simulation results, determine the changes in the states of each subsystem in the hydrogen hybrid aircraft power system, as well as the matching of the output power of each subsystem with the required power.

[0054] Specifically, in step S1, the state and state transition condition of each subsystem, as well as the output generated by each subsystem in different states are determined, specifically including:

[0055] By analyzing the working mechanism of the hydrogen hybrid aircraft power system to be simulated, the subsystems in the hydrogen hybrid aircraft power system to be simulated are identified, including the hydrogen storage system, hydrogen internal combustion engine, generator, battery and electric motor, and the functions of each subsystem are extracted.

[0056] Based on the extracted functions of each subsystem, define the state and state transition conditions of each subsystem, as well as the outputs generated by each subsystem under normal and abnormal working conditions.

[0057] In step S2, the finite state machines of each subsystem are connected in series and in parallel to construct a finite state machine network, including the following steps:

[0058] By defining the states of each subsystem under normal and abnormal working conditions, such as the possible states of the hydrogen storage system include "normal operation", "leakage" and "empty".

[0059] The state and state transition conditions of each subsystem are modeled using a finite state machine, wherein the finite state machine of each subsystem includes a state set, an event set, a transition function, an initial state, and a terminal state.

[0060] Construct a finite state machine network and connect the finite state machines of each subsystem through the network to simulate the interactions and dependencies between the finite state machines of each subsystem. For example, changes in the state of the hydrogen storage system may trigger changes in the state of the hydrogen internal combustion engine.

[0061] The various variables in the hydrogen hybrid aircraft power system to be simulated, including power and hydrogen supply, are used as the input and output of the state machine of each subsystem in the finite state machine network. Hazardous events or "a variable exceeding a threshold" are regarded as state transition conditions. The finite state machines of each subsystem are integrated in series and parallel to form a finite state machine network; the interactions and dependencies between the subsystems are simulated.

[0062] Obtaining simulation results includes the following steps:

[0063] Set the initial conditions of the simulation, including the state of each subsystem and the overall working mode of the hydrogen hybrid aircraft power system to be simulated. For example, set the initial state of the internal combustion engine to off and the initial battery charge to 100%.

[0064] Set fault injection conditions, including failure modes of hydrogen leakage and battery thermal runaway, and set specific parameters for each failure mode, including leakage rate and thermal runaway temperature threshold.

[0065] Set the time span of the simulation, including takeoff, cruise, and landing phases.

[0066] The constructed finite state machine network is executed using simulation software, which should be able to handle multi-threading and real-time data updates to ensure the accuracy and real-time performance of the simulation.

[0067] During the simulation, the power output by the finite state machine network is compared with the required power input.

[0068] Record and analyze the performance parameters of the hydrogen hybrid aircraft power system to be simulated under fault conditions, including power output, battery temperature, hydrogen internal combustion engine temperature, battery remaining power and hydrogen remaining amount.

[0069] The simulation is performed, including the states of each subsystem under normal and abnormal working conditions. For each fault condition under abnormal working conditions, the entire process of the hydrogen hybrid aircraft power system to be simulated from the occurrence of the fault to the termination state is recorded.

[0070] In step S3, the impact of potential risk points on flight safety is analyzed, including:

[0071] Based on the simulation results, fault propagation paths are identified, that is, how faults spread in the system and how they affect other parts of the system. For example, hydrogen leakage may cause the performance of the hydrogen internal combustion engine to deteriorate, thereby affecting the output of the entire power system.

[0072] Determine the potential risk points in the hydrogen hybrid aircraft power system to be simulated, analyze the impact of potential risk points on flight safety, analyze the impact of faults on the performance of the hydrogen hybrid aircraft power system and the fault propagation mechanism, and obtain the analysis results of the impact of faults on the performance of the hydrogen hybrid aircraft power system and the fault propagation mechanism.

[0073] Among them, the impact of faults on the performance of hydrogen hybrid aircraft power systems and the fault propagation mechanism are analyzed, including:

[0074] Based on the recorded and analyzed performance parameters of the hydrogen hybrid aircraft power system to be simulated under fault conditions, the power system response and safety of the hydrogen hybrid aircraft power system to be simulated during take-off, cruising and landing phases under normal and abnormal working conditions are evaluated.

[0075] Based on the simulation results, suggestions are put forward to improve the safety of the hydrogen hybrid aircraft power system to be simulated. The suggestions include improving the design of the hydrogen storage system, enhancing the thermal management of the battery, and optimizing the fault detection and response mechanism.

[0076] Design and simulate the implementation effects of improvement measures, and evaluate the extent to which the implementation effects improve system security.

[0077] The present invention also proposes a hydrogen hybrid aircraft power system safety simulation analysis system, comprising:

[0078] The system decomposition module is used to decompose the hydrogen hybrid aircraft power system to be simulated into multiple subsystems, and to determine the state and state transition conditions of each subsystem, as well as the output generated by each subsystem in different states by extracting the functions of each subsystem;

[0079] The simulation module is used to construct the finite state machine of each subsystem according to the state of each subsystem, the state transition condition and the output generated by each subsystem in different states, and construct a finite state machine network by connecting the finite state machines of each subsystem in series and in parallel; according to the constructed finite state machine network, set the initial conditions, fault injection conditions and simulation time span of each subsystem, execute the simulation by setting the power demand and the flight mission profile, and obtain the simulation results;

[0080] The safety assessment module is used to determine the changes in the status of each subsystem in the hydrogen hybrid aircraft power system and the matching of the output power of each subsystem with the required power based on the simulation results.

[0081] The safety simulation analysis method for the hydrogen hybrid aircraft power system proposed in the present invention can effectively improve the accuracy of safety assessment and reduce the reliance on subjective judgment.

[0082] Example

[0083] In order to verify the feasibility of the method proposed in the present invention, a safety simulation analysis method of an aviation power system is used as an example for simulation. The safety simulation analysis method of an aviation power system specifically includes the following steps:

[0084] Step 1: Analyze the system principles of the hydrogen hybrid aircraft power system of the described aviation power system, identify the subsystems in the hydrogen hybrid aircraft power system to be simulated, the subsystems include hydrogen storage system, hydrogen internal combustion engine, generator, battery and electric motor, and extract the key functions of each subsystem in the hydrogen hybrid aircraft power system.

[0085] Based on the extracted key functions of each subsystem in the hydrogen hybrid aircraft power system, the state and state transfer conditions of each subsystem, as well as the outputs generated in different states, are defined.

[0086] Step 2: Use a finite state machine to model each subsystem of the hydrogen hybrid aircraft power system, set the subsystem state, and consider the possible failure modes of a single system, such as normal operation, hydrogen leakage, and battery thermal runaway, as the state of the state machine.

[0087] Define predictable states for each subsystem, which can be simply divided into two categories: normal working state and fault state. For example, the normal working state of the battery subsystem includes "charging" and "discharging"; the fault state of the battery subsystem includes "overheating" and "thermal runaway".

[0088] The status of each subsystem is defined as shown in Table 1.

[0089] Table 1 Hydrogen storage system status table

[0090]

[0091] Table 2 Hydrogen internal combustion engine status table

[0092]

[0093] Table 3 Generator status table

[0094]

[0095] Table 4 Battery status table

[0096]

[0097]

[0098] Table 5 Electric motor status table

[0099]

[0100] Step 3: Based on the working principle of the hydrogen hybrid aircraft power system, construct the interactions and dependencies between the subsystems, and integrate the state machines of these subsystems in series and parallel to form a comprehensive finite state machine network.

[0101] The various variables in the hydrogen-electric hybrid system, such as power and hydrogen supply, are regarded as the input and output of each sub-state machine in N, and the hazardous event or "a variable exceeds a certain threshold" is regarded as the transfer condition. The finite state machine network can clearly describe the normal working characteristics and failure propagation process of the hydrogen-electric hybrid system.

[0102] For example, the hydrogen storage system's ability to output hydrogen decreases when in a "leakage" state, which in turn causes the hydrogen internal combustion engine to trigger a "power reduction" state due to insufficient hydrogen supply. The output of each subsystem in different states and the interaction between each system are as follows: Figure 2 shown.

[0103] The output formula of the hydrogen storage system is as follows. The output variable is assigned once in each simulation time step:

[0104]

[0105] Among them, hydrogen represents the state of hydrogen output, hydrogen = 2 represents the normal operation of the hydrogen storage system, hydrogen = 1 represents the hydrogen is leaking at this time, and hydrogen = 0 represents the hydrogen is exhausted at this time; State represents the state of the current subsystem, on represents the normal operation of the hydrogen storage device, leaking represents the hydrogen storage device is leaking, and off represents the hydrogen storage device is turned off.

[0106] The output formula of the hydrogen internal combustion engine subsystem is as follows. The output variable is assigned once in each simulation time step:

[0107]

[0108] Among them, power1 i,t It represents the output power when the hydrogen internal combustion engine state machine is in the i-th state at time t, and demand_power represents the demand power.

[0109]

[0110] Among them, temp_ICE t Indicates the average temperature of the hydrogen internal combustion engine at the current moment, Δtemp_ICE i It represents the temperature change of the hydrogen internal combustion engine at each time step in the i-th state, and power1 represents the power output of the hydrogen internal combustion engine.

[0111] The auxiliary power generation power is determined by the current working state of the hydrogen internal combustion engine, that is, by the hydrogen supply state.

[0112]

[0113] Among them, power_a=2 means that the hydrogen internal combustion engine can stably provide auxiliary power generation, power_a=1 means that the ability of the hydrogen internal combustion engine to provide auxiliary power generation is impaired, and power_a=0 means that the hydrogen internal combustion engine does not provide auxiliary power generation at all.

[0114] fuel t+1 =fuel t -Δfuel i

[0115] Among them, Δfuel i Indicates the amount of change in the amount of electricity when the hydrogen internal combustion engine state machine is in the i-th state.

[0116] The output formula of the generator subsystem is as follows, and the output variable is assigned once in each simulation time step:

[0117]

[0118] Wherein, I_generator indicates the state of the generator output current, I_generator=2 indicates that the generator works normally, I_generator=1 indicates that the ability of the generator to output current is affected, and I_generator=0 indicates that the generator cannot output current.

[0119] The output formula of the battery subsystem is as follows, and the output variable is assigned once in each simulation time step:

[0120]

[0121] Wherein, charge_on indicates the charging state. When charge_on=1, it indicates that the battery is in the charging state. When charge_on=0, it indicates that the battery is in the discharging state or other states. i Indicates that the battery is in the i-th charging state.

[0122]

[0123] Among them, I_bat i,t Indicates the output current when the battery state machine is in the i-th discharge state at time t.

[0124]

[0125] Among them, Δsoc i Indicates the amount of charge change when the battery state machine is in the i-th state. discharge i Indicates that the battery is in the i-th discharge state, and Thermalrunaway indicates that the battery is in thermal runaway.

[0126]

[0127] Among them, temp_bat t Indicates the current battery temperature, Δtemp_bat i Represents the temperature change of the battery at each time step when it is in the i-th state.

[0128] The output formula of the electric motor subsystem is as follows, and the output variable is assigned once every simulation time step:

[0129]

[0130] Among them, power2 i,t It represents the power output when the electric motor state machine is in the i-th discharge state at time t.

[0131] Step 4: Set simulation parameters, including initial values ​​of physical variables, simulation time, and initial values ​​of internal variables, and perform simulation in normal working mode without injecting faults and only inputting required power. By setting reasonable power requirements and flight mission profiles, observe and record the changes in the status of each subsystem in the system, as well as the matching of system output power with required power.

[0132] In actual flight, the aircraft needs to have a certain safety margin, such as extra fuel to cope with unforeseen situations. 45 minutes is a typical flight mission time, such as a short flight from one city to another nearby city. The simulation time span is set to 2700s to ensure that the entire flight cycle of the aircraft can be covered, including takeoff, cruising and landing phases.

[0133] Step 5: Set simulation parameters, including initial values ​​of physical variables, simulation time, and initial values ​​of internal variables, and set parameters at the fault injection finite state machine network to simulate a hydrogen leakage event.

[0134] Preset the demand power curve. Define fault injection conditions, such as the time point of hydrogen leakage, the trigger temperature of battery thermal runaway is 110℃, etc.

[0135] Perform simulation to simulate the entire flight process from takeoff to landing, and record the performance parameters of the system under fault conditions, such as power output, temperature, and power. Focus on the cause-effect relationship and the time point of the state transition of each subsystem from the normal working state to the fault state, so as to analyze and improve the design in step 6.

[0136] Step 6: Analyze the simulation results. By identifying the fault propagation path, comparing the simulated output power curve of the hydrogen leakage fault with the normal power curve, and abnormal changes in parameters such as temperature, power, and remaining hydrogen, we can deeply explore the cause and development process of the accident.

[0137] like Figure 3 As shown in the figure, in the time interval from 0 seconds to 450 seconds, the aircraft was in the acceleration and take-off phase, and all systems were operating normally. However, when the time reached 500 seconds, a hydrogen leak occurred. At this time, the aircraft was in the early stage of the climb phase and required higher power. Due to insufficient hydrogen supply, the hydrogen internal combustion engine could not provide sufficient power, resulting in a significant reduction in its output efficiency and auxiliary power generation. At 500 seconds, due to the insufficient power of the hydrogen internal combustion engine, the total output power experienced a brief and sharp drop. At this time, the battery quickly intervened and operated in an overload state, making up for the lack of output power, so that the overall power output was close to the level required for the flight mission.

[0138] As hydrogen continues to leak, the amount of hydrogen in the hydrogen storage tank decreases rapidly. Figure 6 As shown in the figure, the proportion of available hydrogen quickly drops to zero. At 1104 seconds of simulation time, all the hydrogen has been consumed. Due to the interruption of hydrogen supply, the hydrogen internal combustion engine goes from an underpowered state to a completely powerless state, and the power system loses its main power source.

[0139] After 500 seconds of hydrogen leakage, the battery enters an overload state, such as Figure 5 As shown in the figure, the battery power drops rapidly and the battery state of charge (SOC) also decreases rapidly. However, since the battery is in an overload state for a long time, the temperature is too high. Figure 4As shown in the figure, at 1280 seconds of simulation time, the battery temperature exceeded 90°C and entered an overheated state. In this state, the battery's current output capacity is reduced and it cannot provide enough current and voltage for the electric motor, resulting in the electric motor being unable to output enough power to meet the needs of the flight mission. If no measures are taken, the battery will continue to operate in an overheated state and the temperature will reach the thermal runaway threshold of 110°C. Finally, at 2396 seconds of simulation time, the battery exploded and the maximum combustion temperature reached 385.5°C.

[0140] In summary, hydrogen leakage not only affects the performance of the internal combustion engine, but also affects the charging of its redundant unit batteries and causes the batteries to run at high load for a long time, resulting in battery overheating, which in turn affects the performance of the electric motor. If no measures are taken, the battery will continue to operate in an overheated state, causing the battery temperature to reach the thermal runaway threshold of 110°C, triggering battery thermal runaway and explosion, causing a chain reaction to the entire power system.

[0141] Step 7: Based on the results of the simulation analysis, propose improvement measures, such as adding an alarm system. Once a hydrogen leak is detected, the warning light will light up and a warning sound will be issued to remind the pilot to immediately start the emergency plan, and adjust the flight strategy according to the actual status of the battery and power system, such as reducing the flight speed, adjusting the flight altitude or changing the route to reduce power demand and avoid potential major disasters. For example, optimize the battery management system and design a better energy management strategy in the actual hydrogen hybrid aircraft power system to ensure balanced charging and discharging of the battery under high load conditions to avoid over-discharge or overheating. For example, strengthen the thermal management design of the battery, such as using a more effective cooling system to improve heat dissipation efficiency and prevent battery overheating.

[0142] Compared with the traditional safety analysis method, the present invention has the following advantages:

[0143] The present invention can simulate system behaviors in detail both under normal and fault conditions. This method effectively improves the accuracy of safety analysis and reduces reliance on subjective judgment.

[0144] The embodiments provided by the present invention can comprehensively evaluate the impact of key failure modes, such as hydrogen leakage and battery thermal runaway, on system performance, identify potential risk points, and propose targeted improvement measures. These features can provide decision-making references for design and operation, and help optimize the safety design and operation strategy of hydrogen hybrid systems.

[0145] In addition, the application of the present invention is not limited to the aviation field, but may also be extended to other fields, such as automobiles, ships and rail transportation, as well as chemical, energy and manufacturing industries, providing a new analysis tool for safety risk management in these fields. Through the present invention, it can be expected that higher safety standards will be achieved in the design, testing and operation of hydrogen hybrid aircraft, while promoting innovation and development in the field of aviation safety technology.

[0146] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0147] In addition, unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as commonly understood by those skilled in the art to which the present invention belongs. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods related to the documents. In the event of any conflict with any incorporated document, the content of this specification shall prevail.

Claims

1. A safety simulation analysis method for a hydrogen hybrid aircraft power system, characterized in that: The following steps are involved: Decompose the hydrogen hybrid aircraft power system to be simulated into multiple subsystems, extract the functions of each subsystem, determine the state and state transition conditions of each subsystem, and the output generated by each subsystem in different states; According to the state of each subsystem, the state transition conditions and the outputs generated by each subsystem in different states, the finite state machine of each subsystem is constructed, and the finite state machines of each subsystem are connected in series and in parallel to construct a finite state machine network; according to the constructed finite state machine network, the initial conditions, fault injection conditions, simulation time span, power requirements and flight mission profile of each subsystem are set, the simulation is executed, and the simulation results are obtained; Based on the simulation results, the changes in the states of each subsystem in the hydrogen hybrid aircraft power system and the matching of the output power of each subsystem with the required power are determined.

2. The hydrogen hybrid aircraft power system safety simulation analysis method according to claim 1 is characterized in that: The determining of the state and state transition condition of each subsystem, as well as the output generated by each subsystem in different states, specifically includes: By analyzing the working mechanism of the hydrogen hybrid aircraft power system to be simulated, the subsystems in the hydrogen hybrid aircraft power system to be simulated are identified, including the hydrogen storage system, hydrogen internal combustion engine, generator, battery and electric motor, and the functions of each subsystem are extracted; Based on the extracted functions of each subsystem, define the state and state transition conditions of each subsystem, as well as the outputs generated by each subsystem under normal and abnormal working conditions.

3. The safety simulation analysis method for the hydrogen hybrid aircraft power system according to claim 2 is characterized in that: The method of constructing a finite state machine network by connecting the finite state machines of each subsystem in series and in parallel includes the following steps: By defining the states of each subsystem under normal and abnormal working conditions; The state and state transition conditions of each subsystem are modeled using a finite state machine, wherein the finite state machine of each subsystem includes a state set, an event set, a transition function, an initial state, and a terminal state; A finite state machine network is constructed, and the finite state machines of each subsystem are connected through the network. Various variables in the hydrogen hybrid aircraft power system to be simulated, including power and hydrogen supply, are used as the input and output of the state machines of each subsystem in the finite state machine network. Hazardous events or "a variable exceeding a certain threshold" are regarded as state transfer conditions. The state machines of each subsystem are integrated in series and parallel to form a finite state machine network to simulate the interactions and dependencies between the subsystems.

4. The hydrogen hybrid aircraft power system safety simulation analysis method according to claim 3 is characterized in that: The step of obtaining the simulation results comprises the following steps: Obtaining the initial conditions of the simulation, including the status of each subsystem and the overall working mode of the hydrogen hybrid aircraft power system to be simulated; Obtain fault injection conditions, including hydrogen leakage and battery thermal runaway failure modes, and set specific parameters for each failure mode, including leakage rate and thermal runaway temperature threshold; Get the simulated time span and mission profile, including power requirements for takeoff, cruise, and landing; The constructed finite state machine network is executed through simulation software, and the matching degree between the power output by the finite state machine network and the required input power is compared; Record and analyze the performance parameters of the hydrogen hybrid aircraft power system to be simulated under fault conditions, including power output, battery temperature, hydrogen internal combustion engine temperature, battery remaining power and hydrogen remaining amount; The simulation is performed, including the states of each subsystem under normal and abnormal working conditions. For each fault condition under abnormal working conditions, the entire process of the hydrogen hybrid aircraft power system to be simulated from the occurrence of the fault to the termination state is recorded.

5. The safety simulation analysis method for the hydrogen hybrid aircraft power system according to claim 4 is characterized in that: The determination of the change in the state of each subsystem in the power system of the hydrogen hybrid aircraft and the matching of the output power of each subsystem with the required power specifically includes: Based on the simulation results, the fault propagation path is identified to determine the potential risk points in the hydrogen hybrid aircraft power system to be simulated, and then the impact of the potential risk points on flight safety is analyzed. The impact of the fault on the performance of the hydrogen hybrid aircraft power system and the fault propagation mechanism are analyzed, and the analysis results of the impact of the fault on the performance of the hydrogen hybrid aircraft power system and the fault propagation mechanism are obtained.

6. The safety simulation analysis method for the hydrogen hybrid aircraft power system according to claim 5, characterized in that: The analysis of the impact of faults on the performance of the hydrogen hybrid aircraft power system and the fault propagation mechanism specifically includes: Based on the recorded and analyzed performance parameters of the hydrogen hybrid aircraft power system to be simulated under fault conditions, the power system response and safety of the hydrogen hybrid aircraft power system to be simulated during take-off, cruising and landing phases under normal and abnormal working conditions are evaluated.

7. The safety simulation analysis method for the hydrogen hybrid aircraft power system according to claim 5, characterized in that: It also includes making suggestions for improving the safety of the hydrogen hybrid aircraft power system to be simulated based on the simulation results. The suggestions include improving the design of the hydrogen storage system, enhancing the thermal management of the battery, and optimizing the fault detection and response mechanism.

8. A hydrogen hybrid aircraft power system safety simulation analysis system, characterized in that: include: The system decomposition module is used to decompose the hydrogen hybrid aircraft power system to be simulated into multiple subsystems, and to determine the state and state transition conditions of each subsystem, as well as the output generated by each subsystem in different states by extracting the functions of each subsystem; The simulation module is used to construct the finite state machine of each subsystem according to the state of each subsystem, the state transition condition and the output generated by each subsystem in different states, and construct a finite state machine network by connecting the finite state machines of each subsystem in series and in parallel; according to the constructed finite state machine network, set the initial conditions, fault injection conditions, simulation time span, power demand and flight mission profile of each subsystem, execute simulation, and obtain simulation results; The safety assessment module is used to determine the changes in the status of each subsystem in the hydrogen hybrid aircraft power system and the matching of the output power of each subsystem with the required power based on the simulation results.

9. A computer device, characterized in that: The computer device includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps: Decompose the hydrogen hybrid aircraft power system to be simulated into multiple subsystems, extract the functions of each subsystem, determine the state and state transition conditions of each subsystem, and the output generated by each subsystem in different states; According to the state of each subsystem, the state transition conditions and the outputs generated by each subsystem in different states, the finite state machine of each subsystem is constructed, and the finite state machines of each subsystem are connected in series and in parallel to construct a finite state machine network; according to the constructed finite state machine network, the initial conditions, fault injection conditions, simulation time span, power requirements and flight mission profile of each subsystem are set, the simulation is executed, and the simulation results are obtained; Based on the simulation results, the changes in the states of each subsystem in the hydrogen hybrid aircraft power system and the matching of the output power of each subsystem with the required power are determined.

10. A computer-readable storage medium, characterized in that: The computer readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor performs the following steps: Decompose the hydrogen hybrid aircraft power system to be simulated into multiple subsystems, extract the functions of each subsystem, determine the state and state transition conditions of each subsystem, and the output generated by each subsystem in different states; According to the state of each subsystem, the state transition conditions and the outputs generated by each subsystem in different states, the finite state machine of each subsystem is constructed, and the finite state machines of each subsystem are connected in series and in parallel to construct a finite state machine network; according to the constructed finite state machine network, the initial conditions, fault injection conditions, simulation time span, power requirements and flight mission profile of each subsystem are set, the simulation is executed, and the simulation results are obtained; Based on the simulation results, the changes in the states of each subsystem in the hydrogen hybrid aircraft power system and the matching of the output power of each subsystem with the required power are determined.

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