A Three-Dimensional Semi-Analytical Study of the Magnetic Field Excitation in a Radial Surface Permanent-Magnet Synchronous Motor

This paper presents a three-dimensional analytic study of some radial surface permanent-magnet machines, these machines being slotless and without polar pieces. The permanent magnets are represented by Coulomb´s model. The sources are developed into a Fourier series. The method of separation of variables in Laplace´s equations is used to calculate the magnetic scalar potentials, which lead directly to the flux density. The study yielded a new three-dimensional analytical formulation of such synchronous machines. The results are constituted by analytical expressions of magnetic scalar potentials, the flux densities, and some of their graphs