A system look at electromechanical actuation for primary flight control

Abstract

An overview is presented of the emergence of the ALL Electric flight control system (FCS) or power-by-wire (PBW) concept. The concept of fly-by-power refers to the actuator using electrical rather than hydraulic power. The development of the primary flight control Electromechanical Actuators (EMAs) is one of the essential steps in the implementation of the ALL Electric Aircraft. There is a great deal of interest in the application of brushless motors (BM) with rare-earth magnet rotors using external commutation as EMAs flight control systems. The increased complexity of the converter is caused by the fact that thyristor inverters with forced commutation involve additional components and a more complicated mechanical design but a simple control structure, the BM machine must be fed with alternating currents of variabie amplitude, frequency and phase. It is for these reasons that no standard solution for the control of brushless motors has emerged as in the case of the DC motor. The purpose of this book is to present a theoretical investigation of EMAs based on the BM description: electromechanical architecture, magnet materials, operating principles, electromagnetic processes, etc. In order to design current, position, torque, and speed controllers for BM, the general theory of electromechanical and electromagnetic processes in electrical machines in electrical and power converters is used. This book describes a basic approach to the creation of mathematical models for BM with rectangular and sinusoidal current waves. It presents the hardware for position, torque, and current control systems for EMAs. This work also treats the analysis and synthesis of different aircraft power systems with EMAs. Finally, the basic approach for the preliminary design of EMAs is presented.