Research on high-efficiency and low-loss design method of integrated magnetic-geared actuator for aerospace vehicle

Integrated magnetic-geared actuator (IMGA) is a novel electro-mechanical actuator, which is highly integrated by high-speed permanent-magnet motor and magnetic gear. With the characteristics of compact structure, high torque density and non- contact transmission, it has a potential application prospect in the aerospace vehicle. However, the actuator utilizes modulated harmonics with small amplitude and multiple frequency for energy conversion, resulting in large harmonic loss and low efficiency. In order to solve the problems above, research on high-efficiency and low-loss design method of the IMGA for aerospace vehicle is carried out in this paper. Firstly, the loss generation mechanism and distribution are determined. Secondly, the impact of permanent magnet division on eddy loss is investigated. Thirdly, in order to reduce the magnetic-field harmonics, an improved modulating-rotor configuration with sinusoidal surface is proposed. Finally, the influence of input current phase angle on electromagnetic torque and efficiency is conducted. The results show that the eddy loss can be reduced by more than 75% by dividing the permanent-magnet along circumferential direction. The sinusoidal-surface configuration of the modulating rotor can reduce the eddy loss to 73%. By adjusting the input phase angle of the IMGA, the efficiency can be increased by10% without sacrificing torque.