Analytical Model of Flux Reversal Machines With Different Grade Halbach Array

An analytical subdomain model is used to obtain the electromagnetic performance of flux reversal machines with different grade pieced Halbach magnets. In the 2-D polar coordinates, based on the divided four regions, from the Laplace equation and Poisson equations with the boundary conditions in terms of the vector magnetic potential, the partial differential equations are solved by a method of the separation of variables. Then the harmonic coefficients of the magnetic field are determined. The multi-variable optimization of the flux reversal machines with three-/four-piece Halbach array is implemented to improve the performance and the correctness of the analytical model is verified by a finite element method.