| An important indicator to measure the performance of an aeroengine is its thrust adjustment ability,and the rotor speed plays an important role in determining its thrust.The rapidity and dynamic accuracy of rotor speed adjustment are the main performance indicators to measure the speed control performance of aeroengines.The fast response speed control system can increase the maneuverability of aircraft flight,but it is often accompanied by large speed overshoot.The overshoot of the speed will not only increase fuel consumption,but also cause the vibration of the rotor blades and even cause surge.Therefore,in addition to meeting the performance requirements of the engine,its safety protection is also important.It is of great significance to study the dynamic response of aero-engine speed control without overshoot,and to take into account the safety protection of the speed control system.The main work of this paper is as follows:The speed regulation problem of the two-spool turbofan aircraft engine is studied.According to the passive characteristics of aero-engine and the steady-state corresponding relationship between fuel input and speed output,the controller without overshoot is proposed.According to the passive characteristics of aero-engine and the steady-state corresponding relationship between fuel input and speed output,the controller without overshoot is proposed.In view of the fact that in the process of setting value tracking,the function of integral is to finally accumulate the steady-state oil volume corresponding to the target speed according to the historical error,and the steady-state data table is used to replace the integral function and the proportional function to complete the speed control together.The extent of the oil volume exceeding the target steady-state oil during acceleration is determined by the strength of the proportional control,and the system tracking speed can be adjusted by adjusting the proportional control coefficient.As the speed error tends to zero,the fuel supply synchronously returns to the target fuel supply,so the disadvantage of integral hysteresis can be avoided,thereby avoiding speed overshoot.When the dynamics of the high-pressure rotor are fast enough and only the first-order dynamics of the low-pressure rotor are considered,the speed regulation effect without overshoot is theoretically proved.The simulation results show that the control structure can effectively reduce the speed overshoot when used in a twin-shaft turbofan engine.In addition,in order to enable the system to achieve no-differential speed regulation under constant disturbances,integral control logic is designed in the speed regulation stage,and integral action is added after the set value tracking is completed,and the approximate dynamic model of the engine is calculated online near the target operating point.Parameter,and give the integral time constant accordingly.In order to reduce the dynamic influence of the high-pressure rotor and further improve the speed control effect,a cascade speed control structure based on the static characteristics of the aeroengine is proposed.The simulation results show that the cascade structure can effectively eliminate overshoot.Taking into account the various safety restrictions involved in the flight envelope of aero-engines,the protection circuit and switching mechanism in the process of speed regulation are designed with temperature protection as an example.Due to the control signal jump problem that may be caused by the switching of multiple controllers,the performance of the existing dynamic signal smoother is analyzed and compared,and on this basis,a finite time signal smoother is proposed.The smoother can realize the smooth transition of the signal at the time of the jump and can be completely consistent with the original signal in a limited time. |
