Power System Design for an All-Electric Airplane

Abstract

This paper describes a preliminary design for the electrical power system for a new-technology airplane in which the electrical system is the only secondary system extracting power from the engines. All flight control surface actuation is accomplished by electromechan ical actuators. Hydraulic systems are eliminated from the airplane. The prime mover for the air-conditioning system is an electric motor that drives a bootstrap air-cycle pack. This enables more efficient engine shaft power extraction than the more common but less efficient bleed air extraction. Generators serve as motors to crank the engines. The paper also describes laboratory testing of 270 V dc electric power supply and distribution equipment and components in preparation for flight test of a partial power-by-wire flight control system. The flight control equipment in the flight test is limited to a single pair of electromechan ical actuators driving one of two pairs of active control spoilers on the test airplane. Primary power for the actuators in the flight test airplane is 270 V dc, developed by rectification of 115/200 V, 400 Hz power from the aircraft's conventional electrical system. Backup power is provided by a 270 V lead-acid battery assembled by Boeing.