An Investigation of Electro-Hydraulic High Efficient Power Package Configurations for a More Electric Aircraft System Architecture

The trend for optimized electric secondary power generation and distribution systems in commercial aircraft requires electric actuation technology. Electro-hydraulic systems with electric motor-driven pumps (EMP) will likely serve as bridge technology for several actuation functions in the medium- (or long-) term. They enable to apply dissimilar actuation technologies in critical applications or where intrinsic advantages of hydraulic actuation shall be kept. Following the general design requirements for more electric aircraft (MEA) systems, like higher efficiency, lower cost, easier maintenance, and quicker installation, this study investigates the application of electro-hydraulic high efficient power packages (eHEPP) as electro-hydraulic supply modules. The eHEPP integrates the hydraulic system components and the EMP in a compact line replaceable unit. A variable speed EMP concept is applied to achieve a high efficiency of the eHEPP. Under the assumption that landing gear and empennage flight control actuation is hydraulic, different system configurations, ranging from a centralized system with one main eHEPP to a distributed system with local eHEPPs, are designed. In order to find the best concept the key performance of these configurations is evaluated according to the criteria system mass, reliability, availability and efficiency. The evaluation is based on a steady state system sizing and preliminary safety studies. A typical short range aircraft, similar to the Airbus A320 or the Boeing 737, serves as reference for geometry and flight control concept. The study was performed in cooperation with Liebherr-Aerospace Lindenberg GmbH as part of its contribution to the Clean Sky 2 Systems ITD.