Abstract: In terms of speed oscillation problem of a turbojet engine, according to the non-linear differential equation, the dynamic model and critical factor of proportion coefficient were obtained by the small deviation linearization based on a precondition that the speed closed-loop controller was a PI controller. The Simulink model combined hydraulic mechanic unit and engine model was built to analyze the effect of proportionality coefficient to speed stability. The results show that the speed stability is poor under original design, on the other hand, the system stability can be improved and level of speed oscillation can be decreased by reducing the lever ratio. The new lever which ratio reduced was manufactured according to the simulation results. The semi-physical experiments suggest that phenomenon of regular sinusoidal speed oscillation is disappeared and the maximum level of speed N₁ oscillation is decreased from ±0.38% to ±0.24% which meet the requirement of no more than ±0.3% by using the new lever.

Key words: Turbojet engine;Hydraulic mechanic unit;Speed oscillation;Simulink model;Proportion coefficient;Lever

摘要： 针对涡喷发动机转速摆动问题，在已知燃油调节器中的转速闭环控制器为比例积分控制规律的基础上，根据非线性微分方程，采用小偏差线性化方法，推导了比例系数的动态数学模型，得到了决定比例系数的关键因素。建立了燃油调节器与发动机模型的联合仿真Simulink模型，仿真分析了比例系数对转速稳定性的影响。结果表明：原设计参数在大状态时转速稳定性较差，通过减小杠杆比可提高系统稳定裕度，减小转速摆动量。根据仿真结果加工了杠杆比减小的杠杆，半物理试验表明改进后，原来有规律的正弦摆动现象消失，转速N₁最大摆动量由原来±0.38%减小到±0.24%，满足不超过±0.3%的指标要求。

关键词: 涡喷发动机;燃油调节器;转速摆动;Simulink仿真;比例系数;杠杆