3-D Analytical Model of Magnetic Field for Axial-Flux Permanent Magnet Couplings

Axial-flux permanent magnet coupling (AFPMC) is of significant interest in many industrial applications because it can achieve contactless torque transmission. This article proposes a 3-D analytical model of the air-gap magnetic field for the AFPMC. The analytical model is based on the separation of variables method to solve the Laplace equation and Poisson equation in cylindrical coordinate system. The 3-D analytical magnetic field distribution is calculated by applying the magnetic scalar potential and the modified Bessel functions. According to the superposition principle, the air-gap flux density of driving and driven rotor PMs acting alone is synthesized to obtain the air-gap magnetic density of the AFPMC. Four regression evaluation metrics are used to assess the accuracy of the air-gap magnetic field. Finally, the magnetic field distribution, electromagnetic torque, and axial force calculated by the proposed 3-D analytical model are compared with the 3-D finite element analysis results.