Design of modular, CFRP-encased electrical power systems for more-electric aircraft applications

Decarbonisation of aviation is directly supported by the twin trends of electrification of aircraft, and use of light-weight, carbon fibre reinforced polymer (CFRP) aircraft structures. The concept of creating a modularised electrical power system (EPS), with EPS equipment encased in CFRP opens up new design opportunities for electrification of aircraft systems; reduced weight and volume, reduced time out-of-service due to maintenance. Such systems necessitate an understanding of how electrical and structural systems interact, and the design boundary between the CFRP providing combined electrical and structural functionality, versus CFRP with a purely structural functionality, with a separate electrical system encased in CFRP. A power electronic converter (PEC) is an enabling technology for the more-electric aircraft EPS. The paper identifies the key design interdependencies, trades and integrated systems design levers for design of a CFRP casing for a PEC module through a conceptual case study. This includes the capture of high and low frequency electrical functionality, thermal management requirements, and their interdependencies with the topology and functional role of the PEC and the wider EPS architecture. This knowledge is combined to present a design methodology for the design of composite casings for PEC in modularised, on-board electrical power systems.