Investigation of Electro Hydrostatic Actuators on Torque density Improvement Based on Halbach Array Permanent Magnets

Permanent magnet synchronous motors (PMSMs) are widely used in the aerospace field due to the high power density, high torque density, and high efficiency. Due to the excellent flux-focusing performance, PMs in Halbach array can significantly increase the peak fundamental air-gap flux density of PMSMs and hence, a better torque capacity. In this article, 8-pole 9-slot motors with various PM configurations are compared in terms of optimization methods, magnetic flux density, open-circuit electromotive force, and on-load torque by finite element analysis (FEA). The results show that the machine in Halbach array with 45 ° magnetization has significant flux-focusing capability, which can effectively improve the torque density. Moreover, the machine in Halbach array with 45 ° magnetization exhibits the smallest PM eddy current loss and hence, a higher efficiency.