Search Results

Current More Electric Aircraft (MEA) utilize Liquid Cooling Systems (LCS) for cooling on-board power electronics. In such LCS, coolant pipes around the structure of the aircraft are used to supply water glycol based coolant to sink heat from power electronics and other heat loads in the electronic bay. The extracted heat is then transferred to ram air through downstream heat exchangers. This paper presents a reliability examination of a proposed alternative Autonomous Air Cooling System (AACS) for a twin engine civil MEA case study. The proposed AACS utilizes cabin air as the coolant which is in turn supplied using the electric Environmental Control System (ECS) within the MEA. The AACS consists of electrical blowers allocated to each heat load which subsequently drive the outflow cabin air through the heat sinks of the power electronics for heat extraction. No additional heat exchanger is required after this stage in which the heated air is directly expelled overboard.

The Turboelectric Distributed Propulsion (TeDP) concept uses gas turbine engines as prime movers for generators whose electrical power is used to drive motors and propulsors. For this NASA N3-X study, the motors, generators, and DC transmission lines are superconducting, and the power electronics and circuit breakers are cryogenic to maximize efficiency and increase power density of all associated components. Some of the protection challenges of a superconducting DC network are discussed such as low natural damping, superconducting and quenched states, and fast fault response time. For a given TeDP electrical system architecture with fixed power ratings, solid-state circuit breakers combined with superconducting fault-current limiters are examined with current-source control to limit and interrupt the fault current.

Within aircraft electrical network designs, energy storage systems (ESS) provide a means of decoupling the electrical-mechanical interactions between the aircraft electrical power system and the aircraft engine, meeting peak load demand and maintaining power quality during network disturbances and variable load conditions. Within the literature to date, control and management strategies of ESSs for such applications has primarily focused on normal network operation with only limited coverage on the behavior of such technologies under abnormal conditions and the subsequent impact on the operation of the wider power system. Through modeling and simulation of a generic aircraft electrical system, this paper will highlight the potential risks of the inherent, sub-optimal operation of certain existing control strategies during fault conditions.

Complex certification issues aside, aircraft electrical systems possess a number of attributes that present good opportunities for the implementation of adaptive protection systems. Rather than experiencing the complex upgrade process faced in the application of adaptive protection to grid based networks, the opportunity to incorporate their functionality at the design stage of new aircraft systems encourages their use and even offers the potential to implement highly integrated protection and control systems. The physically compact nature of aircraft electrical systems and the presence of an existing communications infrastructure should permit the use of both local and remotely obtained power system data within the adaptive protection systems, maximizing the opportunities for achieving highly capable systems.