Cylindrical linear Halbach arrays for permanent magnet tubular linear machines

In this paper, some important parameters of cylindrical linear Halbach arrays were presented mathematically and their effect on the field distribution was analyzed by the finite-element method. The results show that the number and axial length of magnet annuli per period have more effect on the field distribution and determine the field pattern in axial direction. With different topologies, cylindrical linear Halbach arrays can generate sinusoidal and flat-roofed fields along axial direction with axisymmetry, so they can be applied in both DC and AC permanent magnet tubular linear machines.