Towards dual and three-channel electrical architecture design for more-electric engines

In recent years, the More-Electric Aircraft (MEA) concept has undergone significant development and refinement, striving towards the attainment of reductions in noise and CO2 emissions, increased power transmission efficiency and improved reliability under a range of flight scenarios. The More-Electric Engine (MEE) is increasingly being seen as a key complementary system to the MEA. With this concept, conventional engine auxiliary systems (i.e. fuel pumps, oil pumps, actuators) will be replaced by electrically-driven equivalents, providing even greater scope for the combined aircraft and engine electrical power system optimisation and management. This concept, coupled with extraction of electrical power from multiple engine spools also has the potential to deliver significant fuel burn savings. To date, single or dual channel electrical power generation and distribution systems have been used in engines and aircrafts. However, with the increasing electrification of flight-critical engine auxiliaries along with the requirement for greater load transfer flexibility, a three-channel architecture should be considered. This paper investigates potential concepts for a three-channel power system architecture in an MEE system. The paper considers issues such as architecture layout and key technologies that may be considered for MEE architecture. Using an extensive database of public domain MEA/MEE power system component failure rates, a detailed fault tree analysis is then presented. This provides a quantitative comparison of dual channel and three-channel architecture candidates under the pertinent failure modes as well as showing the impact of common architecture features on system reliability and robustness. Finally, the paper concludes with a discussion of the ring busbar topology operation and power electronics technology requirements that could successfully implement a flexible and robust three-channel architecture for MEE systems.