Energy modeling and control for improved engine stability and efficiency in air vehicles

This paper explores the potential of active control in end-to-end power trains, with an explicit goal of expanding the operating envelope beyond compressor stall and surge limits to allow a smaller engine to attain the same performance as a larger one. The proposed controllers are derived using novel multi-layered dynamical models of both the compressor and the end-to-end power train. The higher-level models explicitly state the dynamics of stored energy and its derivative, which depend on these aggregate variables and the shared variables at the interfaces of system components. The derivatives of these shared variables are instantaneous power and rate of change of generalized instantaneous reactive power. Thus, the proposed framework for the first time describes the detailed mathematical modeling and control of energy dynamics in end-to-end hybrid power trains. In addition, the proposed multi-layered controller directly supports distributed cooperative exchanges of instantaneous reactive power within and across different parts of the power train, making the effects of active control on energy dynamics almost transparent. Simulations illustrate these new modeling and control concepts on state-of-the-art examples of complex engine stall/surge instabilities exhibiting bifurcations. In particular, there is a non-zero rotor acceleration in the power train for challenging missions, which is not observed by traditional controllers, leading to persistent oscillations. The proposed energy control aligns the rates at which subsystems process energy through reactive power control implemented either through the throttle valve or electric actuation, leading to better transient and steady-state performance. Notably, our proposed controller does not require much energy, thereby opening the door to exploring the potential of small storage (battery) in Turbo-electric Distributed Propulsion (TeDP) systems. Preliminary results show that this cooperative control makes a case for hybrid aircraft relying on fast nonlinear control in the electric part of the power train.     

逆映照仿真技术确定主控变量DCS控制限

以对减四线生产数据处理为例,介绍了自主开发的确定主控变量DCS控制限的逆映照仿真技术。该技术通过模式分类,映照、逆映照,样本变量分布统计,仿真,以及生产检测,可最终给出主控变量的DCS控制限,实施生产优化控制。提出的方法紧密结合生产实际,技术处理严谨,方案切实可行。