Analytical prediction of the flux reversal permanent magnet machine with Halbach array magnets in rotor slot considering saturation

This study presents an improved sub-domain analytical model for the characteristic evaluation of the flux reversal permanent magnet machine with Halbach array magnets (FRPMM-HAM) in rotor slot. The influence of iron saturation is considered by equating iron reluctances into airgap. Based on the different material magnetic permeabilities, the FRPMM-HAM is divided into several regions, including slots, permanent magnets (PMs), airgap and so on. By solving the Maxwell equations in polar coordinate for each region according to the boundary conditions, the vector magnetic potential can be derived. According to the vector magnetic potential, the airgap flux density distributions are predicted and the electromagnetic characteristics are calculated. The average magnetic density of the tooth and yoke is combined with the Bertotti model to calculate the iron loss. Besides, the eddy current loss of PMs is also calculated. The accuracy of analytical results is validated via the finite element method (FEM).