The design of a switched reluctance drive for aircraft flight control surface actuation

The development of the `more electric aircraft´ has received considerable attention due to advances in enabling technologies such as power semiconductors, digital controller integration and electric machines. Key to this concept is the replacement of traditional hydraulic actuation systems with electrical actuation, whereby the control surface is driven from an electrical machine via a mechanical assembly; for example a gearbox and ballscrew. The LEMAS (large electromechanical actuation systems) project jointly funded by the DTI and TRW Aeronautical Systems (Lucas Aerospace) as part of the CARAD initiative was set-up to investigate the issues associated with large EMAs, a key objective being the comparison of two potential drive technologies; switched reluctance and brushless DC. This paper outlines the design and validation of a 25 kW switched reluctance actuator for an aircraft spoiler surface, with a related presentation covering the equivalent brushless DC activities