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

Abstract

This paper presents a permanent magnet spherical motor (PMSM) with 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 three-dimensional magnetic circuit of the entire spherical surface uneven. When the spherical motor completes multi-degree-of-freedom motion, the air-gap magnetic field is severely distorted. In order to solve the above problems, this paper 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 paper. 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 paper lay a theoretical foundation for the structural optimization design of the PMSM with SMC core.