Influence of a novel flux‐absorbing structure on the performance of a surface‐mounted permanent‐magnet motor with overhang

Abstract

The demand for surface‐mounted permanent‐magnet (SPM) motors with high torque and power densities has increased as these motors are becoming more widely used in applications requiring high performance in limited spaces, such as electric vehicles and robot arms. Some studies have increased the torque and power densities, such as hybrid flux permanent‐magnet motors utilising radial and axial magnetic fluxes, dual‐rotor and dual‐stator permanent‐magnet motors. Although these motors offer high performance, there are some problems such as low productivity and poor applicability to small motors have arisen due to their complicated structures. An overhang structure can be a simple and effective means of solving the aforementioned problems. However, the overhang effects do not increase linearly but tend to converge as the length of the overhang increases. Therefore, a novel flux‐absorbing structure (FAS) that effectively enhances the overhang effects of SPM motors even in cases with considerable overhang was proposed. The magnetic flux path from the overhang to the stator can be efficiently improved via the proposed FAS. Thereby, the performances of a SPM motor can be effectively enhanced when the FAS is adopted. The effectiveness of the proposed FAS was verified via a 3D finite‐element analysis and in experiments.