Electric actuation-power quality management of aerospace flight control systems

There is a general move in the aerospace industry to increase the amount of electrically powered equipment on future aircraft. This is generally referred to as the "More Electric Aircraft" and brings with it a number of technical challenges that need to be addressed and overcome. High power, electric actuation systems are being proposed on many new aircraft with ratings up to 50 kW. The actuators are used to move flight control surfaces such as the rudder, aileron, spoiler etc. in order to control the speed and direction of the aircraft during flight. The electrical loads presented by these actuators are dynamic in nature and appear highly nonlinear, drawing nonsinusoidal current waveforms. This has a significant effect on the quality of the power system voltage as it introduces harmonic noise that is seen by other connected loads. This paper describes the work undertaken by TRW in investigating the effects of such electric actuator loads on power quality and the development of practical methods to limit the impact.