Anisotropy Identification for Electromechanical Flight Actuators With Sensorless Rotor Angle Detection

Abstract

Electromechanical actuation of flight control surfaces based on permanent magnet synchronous motors (PMSMs) becomes an important technology for more electric aircraft architectures. Demanding requirements for fault tolerance and small space envelopes make sensorless control modes a promising technology in this field. However, sensorless rotor angle detection is not always feasible because it requires differential magnetic anisotropy properties of the motor. This article investigates this prerequisite for a PMSM with flux concentrating magnet topology and fractional slot concentrating windings. A nonlinear model that approximates inductance with respect to current and in particular rotor angle variations is identified. The observable anisotropic operating domain is conservatively determined through testing and finite element analysis (FEA).