Large Displacement Stability by Design for Robust Aircraft Electric Power Systems 2012-01-2197

More electric aircraft (MEA) architectures have increased in complexity leading to a demand for evaluating the dynamic stability of their advanced electrical power systems (EPS). The system interactions found therein are amplified due to the increasingly integrated subsystems and on-demand power requirements of the EPS. Specifically, dynamic electrical loads with high peak-to-average power ratings as well as regenerative power capabilities have created a major challenge in design, control, and integration of the EPS and its components. Therefore, there exists a need to develop a theoretical framework that is feasible and useful for the specification and analysis of the stability of complex, multi-source, multi-load, reconfigurable EPS applicable to modern architectures.

This paper will review linear and nonlinear system stability analysis approaches applicable to a scalable representative EPS architecture with a focus on system stability evaluation during large-displacement events. Additionally, the paper will present a framework that expands recent work in large-displacement stability theory to enable practical stability analysis of multi-load, multi-source EPS architectures. This framework is based on reachable set control theory and evaluates the effects of bounded and potentially nonlinear system current injections without specific knowledge of the transient load profile of the EPS. Hence, it allows making quantitative statement of stability before detailed analysis in simulation and hardware.

Ultimately, the objective of this work is to develop a simple-to-use tool for analyzing EPS large displacement stability. This development will enable the system integrator to address practical challenges that commonly arise in the specification, design, and expansion of EPS architectures on airborne or other mobile platforms. Such challenges include determining how performance budgets can be allocated to the system during the initial design to enable independent supplier design without compromising a stable integrated system, analyzing possible load growth capability in a given EPS architecture, and identifying how an existing EPS could be modified, if necessary, to ensure system stability for a planned load growth with performance characteristics that cannot be modified.