# ANALYSIS OF SUBSYSTEM INTEGRATION IN AIRCRAFT POWER DISTRIBUTION SYSTEMS

Stability analysis of a baseline power system architecture for modern aircraft is addressed. Power electronic converters are widely used in modern aircraft power distribution systems. Due to their inherent nonlinear characteristics, instabilities may arise while integrating individual subsystems together. Bifurcation analysis is used to identify the type, multiplicity and stability of system trajectories. The complete bifurcation diagram for the baseline power system is drawn. The dependence of the parameter values on the bifurcation behavior of the baseline system is presented.

Considerable attention has been paid in recent years to the development of power-by-wire technologies for modern aircraft. As a result, modern aircraft power distribution systems have seen the widespread use of power electronic converters to drive various loads and actuation systems. Power electronic converters are inherently nonlinear systems. The problem of instability that arises due to the integration of these subsystems has been addressed in the past. It is well known that the classical impedance ratio criterion [1] relies on linear analysis techniques in the determination of stability of the interconnected system but it only guarantees local stability in the neighborhood of an equilibrium solution. The application of nonlinear analysis techniques to gain a global understanding of the behavior of the system thus becomes important. However, nonlinear analysis methods do not immediately appeal to the system designer because of their mathematical complexity. In , nonlinear methods were used in the analysis of interaction between an input filter and a regulated power converter modeled as a constant power load. The objective of the paper is to extend this analysis to a baseline power system architecture by studying the bifurcation behavior of the system as a function of a chosen critical parameter. The organization of the paper is as follows: Section 2 introduces the sample power distribution system as a single source-single load system. The source subsystem is a three-phase boost rectifier that feeds the 270V DC bus of the power distribution system. The load subsystem is a regulated DC-DC buck converter with a front-end input filter