Search Results

Distributed electrical propulsion for aircraft, also known as turbo-electric distributed propulsion (TeDP), will require a complex electrical power system which can deliver power to multiple propulsor motors from gas turbine driven generators. To ensure that high enough power densities are reached, it has been proposed that such power systems are superconducting. Key to the development of these systems is the understanding of how faults propagate in the network, which enables possible protection strategies to be considered and following that, the development of an appropriate protection strategy to enable a robust electrical power system with fault ride-through capability. This paper investigates possible DC protection strategies for a radial DC architecture for a TeDP power system, in terms of their ability to respond appropriately to a DC fault and their impact on overall system weight and efficiency.

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.

This paper outlines power system architecture trades performed on the N3-X hybrid wing body aircraft concept under NASA's Research and Technology for Aerospace Propulsion (RTAPS) study effort. The purpose of the study to enumerate, characterize, and evaluate the critical dynamic and safety issues for the propulsion electric grid of a superconducting Turboelectric Distributed Propulsion (TeDP) system pursuant to NASA N+3 Goals (TRL 4-6: 2025, EIS: 2030-2035). Architecture recommendations focus on solutions which promote electrical stability, electric grid safety, and aircraft safety. Candidate architectures were developed and sized by balancing redundancy and interconnectivity to provide fail safe and reliable, flight critical thrust capability. This paper outlines a process for formal contingency analysis used to identify these off-nominal requirements. Advantageous architecture configurations enabled a reduction in the NASA's assumed sizing requirements for the propulsors.

NASA's N3-X aircraft design under the Research and Technology for Aerospace Propulsion Systems (RTAPS) study is being designed to meet the N+3 goals, one of which is the reduction of aircraft fuel burn by 70% or better. To achieve this goal, NASA has analyzed a hybrid body wing aircraft with a turboelectric distributed propulsion system. The propulsion system must be designed to operate at the highest possible efficiency in order to meet the reduced fuel burn goal. To achieve maximum efficiency, NASA has proposed to use a superconducting and cryogenic electrical system to connect the electrical output of the generators to the motors. In addition to being more efficient, superconducting electrical system components have higher power density (kW/kg) and torque density (Nm/kg) than components that operate at normal temperature. High density components are required to minimize the weight of the electric propulsion system while meeting the high power demand.