Analytical model of magnetic force for stack PMB applied in wind power generator

With an aim at the large capacity permanent magnet bearings(PMB) in engineering, stack PMB structure was presented in this paper. Based on differential coefficient of magnetic energy to virtual displacement method and superposition principle, the analytical model of magnetic force for stack PMB was established Its correctness was verified by ANSYS simulation. Results indicates that the axial magnetic force of stack PMB is proportion to the magnetic annular average perimeter and the square of residual magnetism induction density, and that the axial magnetic force increases with an increment in the magnetic annular number, magnetic annular radial width and axial length. At the condition of axial total length and other shape parameter fixedness, the magnetic force of reversal magnetization axial stack PMB is consumedly enhanced, and the magnetic force of same direction magnetization axial stack PMB isn´t increased The axial magnetic force of same direction magnetization axial stack PMB is maximum at the condition of axial offset approximate equal to the axial length of single magnetic ring, The axial magnetic force of reversal magnetization axial stack PMB is maximum at the condition of axial offset approximate equal to the half axial length of single magnetic ring.