Designing Fail-Safe Architectures for Aircraft Electrical Power Systems

More-electric, hybrid-electric, and all-electric aircraft have one important thing in common: they increasingly rely on electrical components and electrical power systems for fulfilling their principal functions. The increased dependency on electrical power has a drastic impact on the nature of the power generation and distribution system within the aircraft. New electrical components, often safety-critical, require completely rethinking of established electrical power system architectures. Manual (re)design, verification, and test of these complex systems becomes costly, cluttered, and often even infeasible. With a new methodology and software tool, we provide the ability to combine different aspects within the early design phases of electrical power systems. Based on a declarative component-based model, a designer can use the tool to automatically generate architectural variants. The component-based models seamlessly integrate with safety and reliability models in the form of component fault trees, which combine the traditional expressiveness of fault tree analysis for failure behavior with some notable advantages. Component fault trees enable the automatic ranking of the generated architectures in terms of safety and reliability attributes. By associating performance models with the original models, the tool also enables verifying complex functional requirements for the ranked architectures, again in a largely automated fashion. We demonstrate the developed methodology on two realistic use cases. In addition, we comment on the ability to apply the same methodology for the design of other systems (e.g., hydraulics, avionics). Indeed, the redesign of the electrical power system will often go hand in hand with rethinking other aircraft systems, because of their mutual interface(s).