Frequency-stabilized ignition circuit design method for starting ignition of aero-engine
By setting a sampling resistor and a monostable trigger in the starting and ignition circuit of an aero-engine, the problem of frequency instability under high temperature environment was solved, and stable and reliable discharge spark output was achieved.
Patent Information
- Application Number
- CN202511995804.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-02-13
AI Technical Summary
Existing frequency-stabilized ignition circuits suffer from frequency instability due to component parameter drift under high-temperature environments, causing some products to malfunction.
By setting a sampling resistor in the secondary discharge circuit of the transformer, the discharge current signal is collected, rectified, filtered and isolated, and used as a trigger signal input to the monostable multivibrator. The output is a high-level control signal with a fixed pulse width to control the conduction and turn-off of the switching transistor, replacing the circuit composed of a transistor and a resistor to maintain conduction.
This achieves improved stability and reliability of the ignition circuit under high-temperature conditions, ensuring that only one discharge spark is generated in each cycle, thus improving frequency stability.
Smart Images
Figure CN121520071A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of aero-engine starting ignition, and particularly relates to a frequency stabilization ignition circuit design method for aero-engine starting ignition. BACKGROUND
[0002] The working principle of the aero-engine starting ignition system is as follows: the ignition device converts the low-voltage power provided by the engine into high-voltage pulse power, transmits the high-voltage pulse power to the ignition electrode through the ignition cable, and releases the high-voltage pulse power at the discharge end of the ignition electrode to generate a high-power discharge spark, which is used to ignite the fuel-air mixture in the combustion chamber of the engine and start the engine.
[0003] The existing frequency stabilization ignition circuit schematic diagram is shown in FIG. 1. Figure 1 The input power supply voltage is converted into a constant 9V DC voltage by the U1 power supply integrated circuit to provide a stable power supply for U2, U3 and U4. U2 is a PWM pulse generation circuit, and the pulse signal drives Q1 to be turned on. During the period when Q1 is turned on, the power supply current linearly increases through the primary winding of T1. The electromotive force induced by the secondary winding of the transformer is cut off due to the reverse bias of D4, so that the electric field energy provided by the input power supply voltage is converted into magnetic field energy and stored in the transformer T1. When the drive signal is at a low level, Q1 is turned off, the electromotive force induced by the secondary winding of the transformer is conducted due to the forward bias of D4, and the capacitor C8 is charged. When the voltage across the capacitor C8 reaches the breakdown voltage of V1, V1 is turned on, and the high-voltage power stored in the capacitor C8 is transmitted to the ignition electrode through the ignition cable to discharge. In the discharge circuit, a voltage signal is formed on the resistor R13. After the signal is rectified and filtered, the signal is transmitted to the Q2, Q3, R9 and R8 maintaining conduction circuit through the U4 isolation drive. When the synthesized circuit is turned on, the drive signal of Q1 becomes a low level and cannot be turned on.
[0004] U3 is a discharge frequency generation signal. When the signal is at a low level, the Q2, Q3, R9 and R8 maintaining conduction circuit is closed, and Q1 continues to be turned on during the high level period of the drive signal generated by U2. The oscillation circuit works stably according to the discharge frequency generation circuit. In a high-temperature environment, the Q2, Q3, R9 and R8 maintaining conduction circuit will be turned on continuously due to the increase of the amplification factor and the leakage current of the transistor. In batch production, due to the difference of the transistor and the increase of the leakage current, some products will be continuously turned on in a high-temperature environment, and the products cannot work normally. SUMMARY
[0005] In order to solve the above problems, the application provides a frequency stabilization ignition circuit design method for aero-engine starting ignition, which mainly comprises the following steps.
[0006] A little ignition circuit is provided, which comprises a power conversion module, a PWM pulse generation module, a switch tube Q1, a transformer T1, a discharge capacitor C8, a discharge tube V1 and a discharge frequency generation module U3.
[0007] A sampling resistor R13 is arranged in the secondary discharge circuit of the transformer T1 for collecting a discharge current signal.
[0008] The voltage signal collected on the sampling resistor R13 is rectified, filtered and isolated, and then input as a trigger signal to the trigger end of a monostable trigger U5.
[0009] The monostable trigger U5 outputs a high-level control signal with a fixed pulse width after receiving the trigger signal.
[0010] The high-level control signal is applied to the control end of a switch tube Q2 to make it conductive, thereby pulling down the driving signal of the switch tube Q1 and forcing the switch tube Q1 to turn off, interrupting the energy storage process of the ignition circuit.
[0011] The fixed pulse width time determined by the timing element of the monostable trigger U5 ensures that it continuously outputs high level until the enable signal provided by the discharge frequency generation module U3 to the monostable trigger U5 becomes low level, the output of the monostable trigger U5 returns to low level, the switch tube Q2 turns off, the driving signal of the switch tube Q1 recovers, and the ignition circuit enters the next working period.
[0012] Preferably, the fixed pulse width of the monostable trigger U5 is determined by the charging and discharging time constant of a resistor R8 and a capacitor C14 connected externally.
[0013] Preferably, the rectification, filtering and isolation process is realized by an isolation driving chip U4.
[0014] Preferably, the output end of the monostable trigger U5 is connected to the control end of the switch tube Q2 through a diode D6 and a current-limiting resistor R7.
[0015] The second aspect of the present application provides a stable frequency ignition circuit for starting ignition of an aero-engine, which is constructed by using the design method described above, and the circuit comprises:
[0016] A power conversion module U1 is used to convert the input power into a stable DC voltage.
[0017] A PWM pulse generation module U2 is connected to the power conversion module U1 for generating a PWM driving signal.
[0018] A switch tube Q1, a control end of which is connected to an output end of the PWM pulse generation module U2, and a main circuit of which is connected in series with a primary winding of the transformer T1;
[0019] A discharge frequency generation module U3 for providing a reference discharge frequency signal;
[0020] A sampling module including a sampling resistor R13 arranged in a secondary discharge circuit of the transformer T1;
[0021] A signal processing module including a rectification filter unit and an isolation unit U4 connected in sequence, and generating a low-level pulse signal based on a high-level signal output by the sampling resistor R13;
[0022] A maintaining conduction module including a monostable trigger U5, a trigger end of which is connected to an output end of the isolation unit U4, and an output end of which is connected to a control end of a switch tube Q2; an output end of the switch tube Q2 is connected to a control end of the switch tube Q1;
[0023] Preferably, the monostable trigger U5 is configured to output a high-level signal with a fixed pulse width after receiving a trigger signal from the sampling module, to turn off the Q1 by driving the Q2 to be turned on, so as to realize that only one discharge spark is generated in each discharge period.
[0024] Preferably, a resistor R8 and a capacitor C14 are connected to a timing end of the monostable trigger U5.
[0025] Preferably, the isolation unit U4 is an optical coupler or an isolation driving chip.
[0026] Preferably, a diode D6 and a resistor R7 are connected in series between the output end of the monostable trigger U5 and the control end of the switch tube Q2.
[0027] The third aspect of the present application provides an aero-engine starting ignition system, including the frequency-stable ignition circuit, an ignition cable and an ignition nozzle as any one of the above.
[0028] The present application solves the problem of frequency instability of the aero-engine ignition device in a high-temperature environment caused by element parameter drift by using an integrated circuit to generate a maintaining conduction signal to replace a maintaining conduction circuit composed of a transistor and a resistor, and significantly improves the stability, consistency and reliability of the product. BRIEF DESCRIPTION OF DRAWINGS
[0029] Figure 1 is a schematic diagram of a current ignition circuit structure.
[0030] Figure 2 is a schematic diagram of a frequency-stable ignition circuit system of an aero-engine starting ignition of the present application.
[0031] Figure 3 Yes, this is a block diagram of the ignition system. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.
[0033] The first aspect of this application provides a design method for a frequency-stabilized ignition circuit for starting and igniting an aero-engine, such as... Figure 2 As shown, it mainly includes:
[0034] An ignition circuit is provided, which includes a power conversion module, a PWM pulse generation module, a switching transistor Q1, a transformer T1, a discharge capacitor C8, a discharge transistor V1, and a discharge frequency generation module U3.
[0035] A sampling resistor R13 is set in the secondary discharge circuit of the transformer T1 to collect the discharge current signal;
[0036] The voltage signal collected on the sampling resistor R13 is rectified, filtered, and isolated, and then used as a trigger signal to be input to the trigger terminal of a monostable multivibrator U5.
[0037] Using the monostable multivibrator U5, after receiving the trigger signal, a high-level control signal with a fixed pulse width is output;
[0038] The high-level control signal is applied to the control terminal of a switch Q2 to turn it on, thereby pulling the drive signal of the switch Q1 low, forcing the switch Q1 to turn off, and interrupting the energy storage process of the ignition circuit.
[0039] The fixed pulse width time determined by the timing element of the monostable multivibrator U5 ensures that it continuously outputs a high level until the enable signal provided by the discharge frequency generation module U3 to the monostable multivibrator U5 becomes low. The output of the monostable multivibrator U5 then returns to a low level, the switch Q2 is turned off, the drive signal of the switch Q1 is restored, and the ignition circuit enters the next working cycle.
[0040] In some alternative embodiments, the fixed pulse width of the monostable trigger U5 is determined by the charging and discharging time constant of a resistor R8 and a capacitor C14 connected externally.
[0041] In some alternative embodiments, the rectification, filtering and isolation process is achieved by an isolation driving chip U4.
[0042] In some alternative embodiments, the output of the monostable trigger U5 is connected to the control terminal of the switch tube Q2 through a diode D6 and a current-limiting resistor R7.
[0043] Reference Figure 2 The monostable trigger U5 of the present application is the core logic device. After receiving a valid trigger pulse, it will output a fixed-width high-level pulse, and then automatically restore to low level. The fixed width is determined by the external RC circuit. The resistor R8 and the timing capacitor C14 are connected in the RC network on U5, and the time constant directly determines the width of the high-level pulse output by U5. The switch tube Q2 is controlled by the output signal of U5. When Q2 is turned on, it will pull down the drive signal of Q1, so that the main circuit stops working. The discharge frequency generator U3 provides the reference rhythm of the entire system. The following describes the circuit principle provided by the present application.
[0044] When a discharge occurs, the voltage signal on the resistor R13 in the discharge circuit is rectified, filtered and isolated by U4, shaped into a negative sharp pulse, and applied to the 2 pin of U5. This jump from high level to low level is the valid trigger signal of the monostable trigger U5. U5 is activated immediately after recognizing the falling edge. After U5 is triggered, it enters its transient state process, which is dominated by the charging and discharging of R8 and C14. The 3 pin output of U5 jumps from low level to high level. The high level output by U5 drives the switch tube Q2 through D6 and R7, so that it changes from cutoff state to saturated conduction state. After Q2 is turned on, the drive signal (gate / base) of Q1 is clamped to low level, forcing Q1 to turn off immediately. At this time, no matter how the PWM signal of U2 changes, Q1 cannot be turned on, and the main oscillation circuit stops working, thereby ensuring that the next energy storage and discharge will not occur immediately after a discharge, and achieving "maintain off".
[0045] During the turn-off process, the capacitor C14 continuously discharges, and its voltage continuously decreases. The time duration is called the fixed pulse width time. The fixed pulse width time determined by the timing element of the monostable trigger U5 ensures that U5 continuously outputs a high level until the output of R5 returns to a low level when U3 provides a low level signal, and the switch tube Q2 is turned off. It can be understood that the 3-pin output of the discharge frequency generation module U3 is low, and the low level signal is transmitted to the 4-pin of U5 as an enable signal, so that the 3-pin output of U5 is low. Since the output of U5 becomes low, the switch tube Q2 loses the driving signal and returns to the off state from the on state. At this time, the forced pull-down of the Q1 driving signal is released, and Q1 is turned on again.
[0046] The circuit ensures that there is only one discharge in each cycle, so that the ignition system can achieve fixed frequency discharge spark output according to the discharge frequency signal provided by the discharge frequency generator, that is, stable frequency ignition, so as to ensure stable discharge frequency.
[0047] The second aspect of the application provides a stable frequency ignition circuit for starting ignition of an aero-engine, which is constructed by using the design method as described above, as shown in the figure, the circuit comprises: Figure 2
[0048] A power conversion module U1 is used to convert the input power into a stable DC voltage;
[0049] A PWM pulse generation module U2 is connected to the power conversion module U1 and is used to generate a PWM driving signal;
[0050] A switch tube Q1 is connected to the output end of the PWM pulse generation module U2 at the control end, and the main circuit is connected in series with the primary winding of the transformer T1;
[0051] A discharge frequency generation module U3 is used to provide a reference discharge frequency signal;
[0052] A sampling module comprises a sampling resistor R13 arranged in the secondary discharge circuit of the transformer T1;
[0053] A signal processing module comprises a rectifier filter unit and an isolation unit U4 connected in sequence, and generates a low level pulse signal based on the high level signal output by the sampling resistor R13;
[0054] A maintaining on module comprises a monostable trigger U5, the trigger end of the monostable trigger U5 is connected to the output end of the isolation unit U4, the output end of the monostable trigger U5 is connected to the control end of a switch tube Q2, and the output end of the switch tube Q2 is connected to the control end of the switch tube Q1;
[0055] The monostable trigger U5 is configured to output a high level signal with a fixed pulse width after receiving a trigger signal from the sampling module, and to turn off Q1 by driving Q2 to be on, so as to realize that only one spark is generated in each discharge period.
[0056] In some optional embodiments, the timing end of the monostable trigger U5 is connected with a resistor R8 and a capacitor C14.
[0057] In some optional embodiments, the isolation unit U4 is an optical coupling or an isolation driving chip.
[0058] In some optional embodiments, the output end of the monostable trigger U5 and the control end of the switch tube Q2 are connected in series with a diode D6 and a resistor R7.
[0059] The third aspect of the present application provides an aero-engine starting ignition system, as shown in the drawings, comprising the frequency-stabilized ignition circuit, an ignition cable and an ignition nozzle according to any one of the above. Figure 3
[0060] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims
1. A design method for a frequency-stabilized ignition circuit for starting and igniting an aero-engine, characterized in that, Includes the following steps: An ignition circuit is provided, which includes a power conversion module, a PWM pulse generation module, a switching transistor Q1, a transformer T1, a discharge capacitor C8, a discharge transistor V1, and a discharge frequency generation module U3. A sampling resistor R13 is set in the secondary discharge circuit of the transformer T1 to collect the discharge current signal; The voltage signal collected on the sampling resistor R13 is rectified, filtered, and isolated, and then used as a trigger signal to be input to the trigger terminal of a monostable multivibrator U5. Using the monostable multivibrator U5, after receiving the trigger signal, a high-level control signal with a fixed pulse width is output; The high-level control signal is applied to the control terminal of a switch Q2 to turn it on, thereby pulling the drive signal of the switch Q1 low, forcing the switch Q1 to turn off, and interrupting the energy storage process of the ignition circuit. The fixed pulse width time determined by the timing element of the monostable multivibrator U5 ensures that it continuously outputs a high level until the enable signal provided by the discharge frequency generation module U3 to the monostable multivibrator U5 becomes low. The output of the monostable multivibrator U5 then returns to a low level, the switch Q2 is turned off, the drive signal of the switch Q1 is restored, and the ignition circuit enters the next working cycle.
2. The design method for aero-engine starting ignition frequency stabilization ignition circuit according to claim 1, characterized in that, The fixed pulse width of the monostable trigger U5 is determined by the charging and discharging time constants of a resistor R8 and a capacitor C14 connected externally to it.
3. The design method for aero-engine starting ignition frequency stabilization ignition circuit according to claim 1 or 2, characterized in that, The rectification, filtering, and isolation processes are implemented through an isolation driver chip U4.
4. The design method for aero-engine starting ignition frequency stabilization ignition circuit according to claim 1, characterized in that, The output of the monostable multivibrator U5 is connected to the control terminal of the switching transistor Q2 via a diode D6 and a current-limiting resistor R7.
5. A frequency-stabilized ignition circuit for starting and igniting an aero-engine, constructed using the design method described in any one of claims 1-4, characterized in that, The circuit includes: The power conversion module U1 is used to convert the input power into a stable DC voltage; The PWM pulse generation module U2 is connected to the power conversion module U1 and is used to generate PWM drive signals; The control terminal of the switching transistor Q1 is connected to the output terminal of the PWM pulse generation module U2, and its main circuit is connected in series with the primary winding of the transformer T1. The discharge frequency generation module U3 is used to provide a reference discharge frequency signal; The sampling module includes a sampling resistor R13 installed in the secondary discharge circuit of transformer T1; The signal processing module includes a rectifier and filter unit and an isolation unit U4 connected in sequence, which generate a low-level pulse signal based on the high-level signal output by the sampling resistor R13; The on-state module includes a monostable multivibrator U5, the trigger terminal of which is connected to the output terminal of the isolation unit U4, and its output terminal is connected to the control terminal of a switch Q2; the output terminal of the switch Q2 is connected to the control terminal of the switch Q1. The monostable multivibrator U5 is configured to output a high-level signal with a fixed pulse width after receiving a trigger signal from the sampling module, thereby turning off Q1 by driving Q2 to conduct, so that only one discharge spark is generated in each discharge cycle.
6. The frequency-stabilized ignition circuit for starting and igniting an aero-engine according to claim 5, characterized in that, The timing terminal of the monostable multivibrator U5 is connected to a resistor R8 and a capacitor C14.
7. The frequency-stabilized ignition circuit for starting and igniting an aero-engine according to claim 5, characterized in that, The isolation unit U4 is an optocoupler or an isolation driver chip.
8. The frequency-stabilized ignition circuit for starting and igniting an aero-engine according to claim 5, characterized in that, A diode D6 and a resistor R7 are connected in series between the output terminal of the monostable multivibrator U5 and the control terminal of the switching transistor Q2.
9. An aircraft engine starting and ignition system, characterized in that, Includes the frequency-stabilized ignition circuit, ignition cable, and ignition nozzle as described in any one of claims 5-8.