Aero-engine over-rotation protection method and device

Abstract

The invention provides an aero-engine over-rotation protection method and device, and the method comprises the steps: 1, obtaining a second rotation speed of an engine through the fuel flow and rotation speed data collected in real time; 2, according to the difference between the second rotating speed and the maximum rotating speed, different fuel oil flow adjusting rates are dynamically switched, and acceleration response and over-rotating protection are guaranteed; and step 3, a rotating speed deviation elimination algorithm: adopting feedforward-feedback compound control, dynamically correcting the rotating speed deviation, and ensuring the precision and safety of instruction tracking.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aero-engine control and safety protection, and particularly relates to an aero-engine over-speed protection method and device. BACKGROUND

[0002] In the working process of an aero-engine, the combustion chamber, as a key component of energy conversion, has large thermal and mechanical inertia. The current engine control system usually adopts a simple closed-loop control strategy, which is difficult to balance fast response and over-speed protection, and is prone to cause speed overshoot due to inertia during acceleration. When the instruction speed is close to the maximum safe speed, the traditional PID control is prone to overshoot due to integral saturation, which endangers the safety of the engine. At the same time, the traditional control method is difficult to balance between power response and safety protection, which affects the overall performance and service life of the engine. SUMMARY

[0003] The application provides an aero-engine over-speed protection method and device, which can solve the problem of low overall performance and service life of the engine.

[0004] TECHNICAL SCHEME In a first aspect, the application provides an aero-engine over-speed protection method, which comprises the following steps: Step 1: obtaining a second speed of the engine by real-time collection of fuel flow and speed data ; Step 2: dynamically switching different fuel flow regulation rates according to the gap between the second speed and the maximum speed, to ensure acceleration response and over-speed protection Step 3: using a feedforward-feedback compound control to dynamically correct the speed deviation, to ensure the accuracy and safety of instruction tracking.

[0005] Preferably, step 1 comprises: Step 11: calculating the inertia time constant using the inertia time constant estimation formula , wherein is the sampling period, N is the number of data points in the sliding window, is the fuel flow, is the first speed collected in real time; Step 12: calculating the second speed using the time domain differential equation according to the inertia time constant , wherein K is the gain coefficient.

[0006] Preferably, step 2 comprises: Step 21: Maximum speed according to engine control strategy Set the starting speed of the fast acceleration zone. Where L is the second rotational speed Percentage of maximum speed; Step 22: Based on the starting speed of the fast acceleration zone For the second rotational speed Make a judgment; Step 23: If In the rapid acceleration zone, a larger fuel flow rate increment is allowed, and an upper limit is set for the rate of change of fuel flow. ; like In the slow acceleration zone, fine-tuning of fuel flow is employed, with an upper limit set for the rate of change of fuel flow. ; Step 24: Based on the switching criteria , confirm use or As the fuel flow rate regulation rate.

[0007] Preferably, step 24 includes: The algorithm for predicting the maximum controllable rotational speed in the next sampling period is as follows: , Where K is the gain coefficient. The inertial time constant, For the sampling period, if If there is a tendency to over-rev, then adjust the fuel flow command. Adjustments were made to limit the amplitude and suppress the risk of overshooting in advance.

[0008] Preferably, step 3 includes: Step 31: Based on the target rotational speed Inertial time constant , The feedforward term is calculated based on the desired rotational speed change and the inertial model. ; Step 32: Based on the target rotational speed proportionality coefficient and differential coefficients Using the formula Calculate the feedback term for PID correction based on speed deviation. ; Step 33: Based on the feedforward term and feedback items Using the formula Calculate fuel flow control quantity ; Step 34: Set the deviation elimination criterion ; Step 35: If This will automatically reduce the feedback gain to prevent oscillation. , ,in, ; It is a gain reduction factor. This is the corrected scaling factor. These are the corrected differential coefficients; like This enhances the feedback effect and quickly eliminates deviations. , ,in, ; It is the gain enhancement factor; Step 36: According to and Return to step 32 and use... replace ,use replace Substitute into the formula Calculate feedback items in a loop .

[0009] Secondly, this application provides an overspeed protection device for an aero-engine, comprising a combustion chamber inertial identification module, a fast / slow acceleration zone control module, and a deviation elimination algorithm module, wherein: The combustion chamber inertial identification module is used to obtain the engine's second speed by collecting real-time fuel flow and speed data. ; The fast / slow acceleration zone control module is used to adjust the acceleration based on the second rotational speed. The difference between the maximum speed and the engine speed is dynamically adjusted to switch different fuel flow rates, ensuring acceleration response and over-rev protection. The deviation elimination algorithm module is used for speed deviation elimination algorithms. It adopts feedforward-feedback composite control to dynamically correct speed deviations and ensure the accuracy and safety of command tracking.

[0010] Preferably, the combustion chamber inertial identification module is specifically used for: Estimation formula using inertial time constant Calculate the inertial time constant ,in, Where N is the sampling period, and N is the number of data points within the sliding window. For fuel flow rate, The first rotational speed is collected in real time; based on the inertial time constant. Using time-domain differential equations Calculate the second rotational speed , where K is the gain coefficient.

[0011] Preferably, the fast / slow acceleration partition control module is specifically used for: Maximum speed according to engine control strategy Set the starting speed of the fast acceleration zone. Where L is the second rotational speed Percentage of maximum RPM; based on the starting RPM of the fast acceleration zone. For the second rotational speed Make a judgment; if In the rapid acceleration zone, a larger fuel flow rate increment is allowed, and an upper limit is set for the rate of change of fuel flow. ;like In the slow acceleration zone, fine-tuning of fuel flow is employed, with an upper limit set for the rate of change of fuel flow. According to the switching criteria , confirm use or As the fuel flow rate regulation rate.

[0012] Preferably, the fast / slow acceleration partition control module is also used for: The algorithm for predicting the maximum controllable rotational speed in the next sampling period is as follows: Where K is the gain coefficient. The inertial time constant, For the sampling period, if If there is a tendency to over-rev, then adjust the fuel flow command. Adjustments were made to limit the amplitude and suppress the risk of overshooting in advance.

[0013] Preferably, the deviation elimination algorithm module is specifically used for: According to the target speed Inertial time constant , The feedforward term is calculated based on the desired rotational speed change and the inertial model. According to the target speed proportionality coefficient and differential coefficients Using the formula Calculate the feedback term for PID correction based on speed deviation. According to the feedforward term and feedback items Using the formula Calculate fuel flow control quantity Set deviation elimination criteria ;like This will automatically reduce the feedback gain to prevent oscillation. , ,in, ; It is a gain reduction factor. This is the corrected scaling factor. These are the corrected differential coefficients; if This enhances the feedback effect and quickly eliminates deviations. , ,in, ; It is the gain enhancement factor; according to and Return to step 32 and use... replace ,use replace Substitute into the formula Calculate feedback items in a loop .

[0014] In summary, this application provides a method and apparatus for overspeed protection of an aero-engine, which has the following advantages: 1) The system analyzes the combustion chamber inertia and the current acceleration zone status in real time, and can prevent over-revving under any speed command, thus ensuring flight safety; 2) The fast acceleration zone uses a large-scale fuel adjustment to meet the needs of rapid acceleration; the slow acceleration zone converges in advance to avoid overshoot, taking into account different acceleration needs and ensuring a balance between engine power response and safety. 3) The inertial identification module can dynamically adjust inertial parameters to adapt to changes in different operating conditions, ensuring that the overspeed protection strategy is always effective; 4) Feedforward-feedback composite control can promptly eliminate the deviation between the actual speed and the command, improve command tracking accuracy, and reduce power fluctuations; 5) Emergency fuel reduction or fuel cut-off protection measures are adopted to improve system robustness and safety level; 6) The system has a simple hardware structure, obvious overspeed protection effect, significant economic benefits and application value, and is of great significance to the application and development of the aero-engine field. Attached Figure Description

[0015] Figure 1 A schematic diagram of the functional module structure of the engine over-revving protection device of the present invention. Detailed Implementation

[0016] This invention is primarily used in the fuel control system of aero-engines. Its main function is to identify combustion chamber inertial parameters, implement zoned control of fast / slow acceleration zones, use a deviation elimination algorithm, and incorporate an emergency fuel reduction or fuel cut-off protection module. This provides a safety guarantee for aero-engine over-revving protection and improves the reliability and safety of aero-engine control. The strategies and methods proposed in this paper can be implemented through an aero-engine electric fuel control system.

[0017] Example 1 likeFigure 1 As shown, this application provides a method for overspeed protection of an aero-engine, including: Step 1: Obtain the engine's second speed by collecting real-time fuel flow and speed data. ; The combustion chamber acts as a "low-pass filter" in the engine's dynamic response. Its inertia is mainly reflected in the hysteresis of changes in combustion flow rate to changes in engine speed. To achieve online identification, a first-order inertial element is used to model its dynamics.

[0018] Specifically, step 1 includes: Step 11: Estimation formula using inertial time constant Calculate the inertial time constant ,in, The sampling period is N The number of data points within the sliding window. For fuel flow rate, The first rotational speed is collected in real time.

[0019] Real-time data collection of fuel flow and engine speed over a recent period is performed. Inertial parameters are estimated online using the least squares method. The parameter update strategy is to update the inertial constant every 0.1 seconds. Reasonable range constraints are If the identification result exceeds this range, the value from the previous period will be used. .

[0020] Step 12: Based on the inertial time constant Using time-domain differential equations Calculate the second rotational speed ,in, K This is the gain coefficient.

[0021] It should be noted that the inertial time constant needs to be identified in real time.

[0022] It should be noted that the transfer function is: ,in: K This is the gain coefficient. This is the inertial time constant (which needs to be identified in real time). s These are variables in the complex frequency domain.

[0023] Step 2: Based on the second rotational speed The difference between the maximum speed and the maximum speed is dynamically adjusted to switch different fuel flow rates, ensuring acceleration response and over-rev protection.

[0024] Specifically, step 2 includes: Step 21: Maximum speed according to engine control strategy Set the starting speed of the fast acceleration zone. Where L is the second rotational speed Percentage of maximum speed.

[0025] Where L=0.98.

[0026] Step 22: Based on the starting speed of the fast acceleration zone For the second rotational speed Make a judgment; Step 23: If In the rapid acceleration zone, a larger fuel flow rate increment is allowed, and an upper limit is set for the rate of change of fuel flow. ; like In the slow acceleration zone, fine-tuning of fuel flow is employed, with an upper limit set for the rate of change of fuel flow. ; Step 24: Based on the switching criteria , confirm use or As the fuel flow rate regulation rate.

[0027] In practical applications, the method also includes: utilizing inertial identification parameters. The fuel flow command is fed forward to predict the maximum controllable speed in the next sampling cycle.

[0028] Specifically, the algorithm for predicting the maximum controllable rotational speed in the next sampling period is as follows: , in, K This is the gain coefficient. The inertial time constant, For the sampling period, if If there is a tendency to over-rev, then adjust the fuel flow command. Adjustments were made to limit the amplitude and suppress the risk of overshooting in advance.

[0029] It should be noted that step 2 is used for fast / slow acceleration zone control of the rotation speed.

[0030] Step 3: Speed ​​deviation elimination algorithm, which adopts feedforward-feedback composite control to dynamically correct speed deviation and ensure the accuracy and safety of command tracking.

[0031] Specifically, step 3 includes: Step 31: Based on the target rotational speed Inertial time constant , The feedforward term is calculated based on the desired rotational speed change and the inertial model. ; Step 32: Based on the target rotational speed proportionality coefficient and differential coefficients Using the formula Calculate the feedback term for PID correction based on speed deviation. ; Step 33: Based on the feedforward term and feedback items Using the formula Calculate fuel flow control quantity ; Step 34: Set the deviation elimination criterion ; Step 35: If This will automatically reduce the feedback gain to prevent oscillation. , ,in, ; It is a gain reduction factor. This is the corrected scaling factor. These are the corrected differential coefficients; like This enhances the feedback effect and quickly eliminates deviations. , ,in, ; It is the gain enhancement factor; Step 36: According to and Return to step 32 and use... replace ,use replace Substitute into the formula Calculate feedback items in a loop ; It should be noted that setting the threshold for triggering early speeding warnings is necessary. When the speed At this time, the system is forced into a slow acceleration zone. The emergency cutoff threshold is exceeded. When the speed In such cases, immediately implement emergency fuel reduction or fuel cut-off protection.

[0032] Example 2 like Figure 1 As shown, this application provides an overspeed protection device for an aero-engine, comprising: a combustion chamber inertial identification module, a fast / slow acceleration zone control module, and a deviation elimination algorithm module, wherein: The combustion chamber inertial identification module is used to collect key parameters such as engine speed and fuel flow rate in real time, and to identify the inertial characteristics of the combustion chamber through a dynamic model. An adaptive algorithm is used to adjust the inertial parameters in real time to ensure the accuracy of inertial identification under different operating conditions (such as cold state, hot state, different altitude, etc.).

[0033] The fast / slow acceleration zone control module allows for a larger fuel flow increment when the engine is in the fast acceleration zone and the engine speed is far from the maximum speed range (e.g., below 90% of maximum speed), employing a fast response control strategy to improve power responsiveness. When the engine is in the slow acceleration zone (e.g., above 90% of maximum speed), the control system automatically switches to a fine control mode, limiting the fuel flow increase and extending the acceleration time. It also predicts the hysteresis effect caused by combustion chamber inertia through an inertial identification model, reducing fuel input in advance to prevent overshoot and over-revving.

[0034] The deviation elimination algorithm module uses a feedforward-feedback composite control algorithm to dynamically adjust the fuel flow based on the deviation between the target speed and the actual speed. It corrects speed deviations that may occur during acceleration, and effectively eliminates residual deviations caused by inertia, especially during deceleration or emergency stops, ensuring that the engine always operates within a safe range.

[0035] Specifically, the combustion chamber inertial identification module plays a "low-pass filter" role in the engine's dynamic response. Its inertia is mainly reflected in the hysteresis of changes in combustion flow rate to changes in engine speed. To achieve online identification, a first-order inertial element is used to model its dynamics.

[0036] Transfer function: ,in: K This is the gain coefficient. This is the inertial time constant (which needs to be identified in real time). s For variables in the complex frequency domain. Time-domain differential equation: , For fuel flow input, This is the second output rotational speed. Real-time fuel flow and rotational speed data over a recent period are collected, and the least squares method is used to estimate the inertial parameters online. The inertial time constant estimation formula is as follows: , The sampling period is N The number of data points within the sliding window. For fuel flow rate, The first rotational speed is collected in real time. Parameter update strategy: The inertial constant is updated every 0.1 seconds. Reasonable range constraints are If the identification result exceeds this range, the value from the previous period will be used. .

[0037] Specifically, the fast / slow acceleration zone control module, based on the second speed... The distance from the maximum speed is used to dynamically switch different fuel flow adjustment rates to ensure acceleration response and over-rev protection.

[0038] Threshold setting: Maximum speed based on engine control strategy Set the starting speed of the fast acceleration zone. Where L is the second rotational speed Percentage of maximum speed, where L=0.98. Control strategy: In the fast acceleration zone... Allow for larger fuel flow rate increments, and set an upper limit for the rate of change of fuel flow rate. In the slow acceleration zone It employs meticulous fuel regulation, anticipating the risk of overshoot due to inertia, and sets an upper limit for the rate of change of fuel flow. Switching criteria Combining inertial prediction with inertial identification parameters Feedforward correction is applied to the fuel flow command to predict the maximum controllable speed in the next sampling cycle. , ( K This is the gain coefficient. The inertial time constant, (for the sampling period), if If there is a tendency to over-rev, then adjust the fuel flow command. Adjustments were made to limit the range and mitigate the risk of overshoot.

[0039] Specifically, the deviation elimination algorithm module adopts feedforward-feedback composite control to dynamically correct speed deviations, ensuring the accuracy and safety of command tracking.

[0040] The fuel flow control quantity is composed of the superposition of feedforward and feedback. ,in The feedforward term is calculated based on the desired rotational speed change and the inertial model. The feedforward term is used for PID correction based on speed deviation. , ( For the target speed, (Inertial time constant). Feedback term calculation. , This is the proportionality coefficient. These are the differential coefficients. The deviation elimination criterion states that for small deviations... ,like This will automatically reduce the feedback gain to prevent oscillation. , , ( ), It is a gain reduction factor. This is the corrected scaling factor. These are the corrected differential coefficients; if This enhances the feedback effect and quickly eliminates deviations. , ,in, ; This is the gain enhancement factor. The overspeed early warning trigger threshold. When the speed At this time, the system is forced into a slow acceleration zone. The emergency cutoff threshold is exceeded. When the speed In such cases, immediately implement emergency fuel reduction or fuel cut-off protection.

[0041] This invention provides a method and device for overspeed protection of aero-engines. Through combustion chamber inertial identification, fast / slow acceleration zone control, and deviation elimination, it achieves precise control of engine speed, effectively preventing overspeed under any speed command while also meeting the requirements for rapid acceleration and deceleration. The core processor or computing unit can be flexibly selected. The core architecture of the device is shown in the red circle. The device collects externally input speed, fuel flow rate, and commanded speed. The combustion chamber inertial identification module performs inertial identification parameters based on the collected speed and fuel flow rate. The real-time calculations are used by the fast / slow acceleration zone control module and the deviation elimination module. The fast / slow acceleration zone control module switches between the fast acceleration zone and the slow acceleration zone by commanding the engine speed and collecting the engine speed, dynamically adjusts the feedback gain, and calculates the fuel flow control quantity in conjunction with the deviation elimination algorithm. The emergency fuel reduction or fuel cut-off protection module can immediately execute emergency fuel reduction or fuel cut-off protection by judging the commanding engine speed, the overspeed early warning trigger threshold, and the overspeed emergency cut-off threshold, ensuring that a safe fuel flow control quantity is output to the aircraft engine's electric fuel control system.

Claims

1. An aeroengine overspeed protection method, characterized in that, The method comprises: Step 1: Obtain the second rotational speed of the engine by real-time acquisition of fuel flow and rotational speed data ; Step 2: According to the second rotation speed The difference between the maximum rotation speed, dynamically switching different fuel flow rate adjustment rate, to ensure the acceleration response and over-rotation protection; Step 3: the speed deviation elimination algorithm adopts a feedforward-feedback compound control, dynamically corrects the speed deviation, and guarantees the accuracy and safety of command tracking.

2. The method of claim 1, wherein, Step 1 comprises: Step 11: Estimation of the inertia time constant using the formula , calculate the inertia time constant , where, is the sampling period, N is the number of data points in the sliding window, is the fuel flow, is the first speed of rotation collected in real time; Step 12: Based on the inertial time constant Using time-domain differential equations Calculate the second rotational speed , where K is the gain coefficient.

3. The method of claim 1, wherein, Step 2 comprises: Step 21 : Maximum engine speed according to engine control strategy Set fast acceleration zone start speed Where L is the second speed As a percentage of maximum speed; Step 22: According to the fast acceleration zone start speed , the second rotation speed is judged; Step 23: If then the fast acceleration zone allows a larger fuel flow increment, setting the upper limit of the fuel flow rate change ; If , the slow acceleration zone adopts fine fuel regulation, and sets an upper limit of fuel flow rate change ; Step 24: Determine to use or as the fuel flow rate adjustment rate based on the switching criterion. ​ 4. The method of claim 3, wherein, Step 24 comprises: The algorithm for predicting the maximum controllable rotational speed for the next sampling period is: , Wherein, K is gain coefficient, is the inertia time constant, is the sampling period, if there is a tendency to over speed, the fuel flow instruction is corrected by limiting the amplitude, and the risk of over speed is suppressed in advance.

5. The method of claim 1, wherein, Step 3 comprises: Step 31 : Calculate target speed based on target speed , inertia time constant , , calculate feed forward term based on desired speed change and inertia model calculation ; Step 32: Calculate the feedback term of the PID correction based on the deviation of the target rotational speed , the proportional coefficient , and the differential coefficient , using the formula ;​ Step 33: Calculate the fuel flow control amount Qf according to the feedforward term and the feedback term ;​​​ Step 34: Set the deviation elimination criterion ; Step 35: If then automatically reduce the feedback gain to prevent oscillation, , where, ; is a gain reduction factor, is the modified proportional coefficient, is the modified derivative coefficient; If , the feedback effect is enhanced, and the deviation is quickly eliminated, , wherein, ; is a gain enhancement factor; Step 36: According to and , return to execute step 32, replace with , replace with , bring into the formula , and loop the feedback term .

6. An aircraft engine overspeed protection device, characterized in that, The combustion chamber inertia identification module, the fast / slow acceleration partition control module and the deviation elimination algorithm module, wherein: An inertial identification module of the combustion chamber is used to obtain the second rotating speed of the engine through the real-time collected fuel flow and rotating speed data ; The fast / slow acceleration zone control module is used to adjust the acceleration based on the second rotational speed. The difference between the maximum speed and the engine speed is dynamically adjusted to switch different fuel flow rates, ensuring acceleration response and over-rev protection. The deviation elimination algorithm module is used for the speed deviation elimination algorithm, adopts a feedforward-feedback compound control, dynamically corrects the speed deviation, and guarantees the accuracy and safety of command tracking.

7. The apparatus of claim 6, wherein, The combustion chamber inertia identification module is specifically used for: The inertia time constant is estimated by using an inertia time constant estimation formula The inertia time constant is calculated Wherein, is a sampling period, N is a number of data points in a sliding window, is a fuel flow, is a first rotation speed collected in real time; according to the inertia time constant A second rotation speed is calculated by using a time domain differential equation Wherein, K is a gain coefficient.

8. The apparatus of claim 6, wherein, The fast / slow acceleration partition control module is specifically used for: maximum engine speed according to engine control strategy , set fast acceleration zone start speed , wherein L is the second speed as a percentage of the maximum speed; determine the second speed according to the fast acceleration zone start speed ; if , the fast acceleration zone allows a larger fuel flow increment, set the upper limit of the fuel flow rate of change ; if , the slow acceleration zone uses fine fuel regulation, set the upper limit of the fuel flow rate of change ; according to the switching criterion , determine to use or as the fuel flow regulation rate.

9. The apparatus of claim 8, wherein, The fast / slow acceleration partition control module is also used for: The algorithm for predicting the maximum controllable rotational speed of the next sampling period is: wherein K is a gain coefficient, is an inertia time constant, is a sampling period, if there is a tendency of over-rotation, the fuel flow command is corrected by limiting the amplitude to suppress the risk of over-rotation in advance.

10. The apparatus of claim 6, wherein, The deviation elimination algorithm module is specifically used for: According to the target speed Inertial time constant , The feedforward term is calculated based on the desired rotational speed change and the inertial model. According to the target speed proportionality coefficient and differential coefficients Using the formula Calculate the feedback term for PID correction based on speed deviation. According to the feedforward term and feedback items Using the formula Calculate fuel flow control quantity Set deviation elimination criteria ;like This will automatically reduce the feedback gain to prevent oscillation. , ,in, ; It is a gain reduction factor. This is the corrected proportionality coefficient. These are the corrected differential coefficients; if This enhances the feedback effect and quickly eliminates deviations. , ,in, ; It is the gain enhancement factor; according to and Return to step 32 and use... replace ,use replace Substitute into the formula Calculate feedback items in a loop .

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