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 permanentmagnet 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.

Novel methodology for direct speed control of a permanent magnet synchronous motor with sensorless operation

“…In Equations (1) is the flux-linkage of the permanent magnet of rotor. Also, ω e is the synchronous speed of the rotor.…”

“…The permanent magnet synchronous motor (PMSM) has high efficiency, high torque to inertia ratio, high power density, and low rotor losses [1,2], which make it a preferable choice in industrial applications. In spite of the mentioned merits of a PMSM, the control method design is demanding [3].…”

Electromagnetic and thermal analyses of surface‐mounted permanent magnet motor with flux‐absorbing structure for enhancing overhang effect

“…Finally, the convection between the stator end region and the internal air and between the rotor end region and the internal air of the enclosed motor is considered as the heat transfer coefficients, h c_s and h c_r in (11) and (12), where ω (rad/s) and r ro (m) correspondingly represent the angular velocity and radius of the rotor [31]. In the case of a motor with the OS, it is required to use the modified heat transfer coefficient using (13) and (14) proposed in earlier work [23,28] h c_s = 6.5 + 5.25 0.6 (ωr ro )…”

“…To address this problem, an effective structure, a flux‐absorbing structure (FAS) attached to the stator, can be utilised [13]. The FAS maximises the effect of the OS by forming an effective magnetic flux path between the OS and the stator core.…”

Generalized and Reduced Analytical Formulation for Ultra-Fast 3-D Field and Vector Potential Calculation From Arch-Shaped Axially Magnetized Bodies in Electrical Machines

“…Overhang structures can sometimes be used to increase the flux density in the air gap. For a detailed analysis, it is normal to distinguish between different overhang parts and non-overhang regions [6]- [8]. Fig.…”