Analytic magnetic field modelling approach for iron-less tubular permanent magnet linear synchronous motors

A novel polygon topology is investigated for improving the manufacturability and cooling of iron-less tubular permanent magnet linear synchronous motors. A collation of analytic equations for permanent magnets and wire filaments is used in a high fidelity and computationally inexpensive model of double-sided Halbach array motor geometries. The analytic equations do not impose boundary conditions in the problem space, allowing for quantification of axial and radial end-effects. A comparative case study is presented for the effectiveness of an n-sided polygon motor relative to an idealised tubular motor. The results show that for a figure of merit, related to the motor constant, the polygon motor converges with a low number of sides, and for larger motor sizes, converges to that of a tubular motor with an equal permanent magnet volume.