Magnetic Field Analysis for the Permanent Magnet Spherical Motor With SMC Core

This article presents a permanent magnet spherical motor (PMSM) with a soft magnetic composite (SMC) core. The analytical model of the no-load air-gap magnetic field of the PMSM with SMC core is obtained based on the Laplace equation with the boundary conditions. When the SMC core is added to the stator teeth, a cogging effect occurs, which makes the 3-D magnetic circuit of the entire spherical surface uneven. When the spherical motor completes a multi-degree-of-freedom motion, the air-gap magnetic field is severely distorted. In order to solve the above problems, this article proposes for the first time the method of adding spherical-shaped pole shoes to the stator teeth, which perfectly solves the problem of magnetic field distortion in this article. The air-gap magnetic field distribution is improved by optimizing the structure of the stator tooth pole shoes. Finally, the static torque measurement platform was built to test the rotation-energized output torque. The research results of this article lay a theoretical foundation for the structural optimization design of the PMSM with SMC core.