Analytical modeling for rotor eccentricity solution in wind power generator with bread loaf PMs

Abstract

This paper presents a novel analytical solution for the magnetic fields of large permanent magnet (PM) wind generator with bread loaf PMs under normal and eccentricity conditions. To simplify the calculation, the generator is first approximately modeled in the Cartesian coordinate, and then the bread loaf PMs are equivalently considered by pairs of coils so that their effects can be expressed by mathematic equations. By applying the Fourier separation method, with the boundary and interface conditions, the magnetic fields in the calculation regions can be obtained by solving system equations. Afterward, the rotor eccentricity is investigated by transforming the corresponding model to a new orthogonal coordinate system by using a conformal mapping technique. Numerical examples validate the proposed method and the calculated results have a satisfactory agreement with the finite element analysis. The established model in this paper has a significant value for modeling large PM wind power generators, and the calculation time is deduced remarkably.