Brushless axial flux EM resolver with asymmetric distribution of inductive material in the rotor

摘要

A brushless axial flux electromagnetic resolver comprising: a stator (4, Fig.1) carrying output and excitation windings (10, 12, 6, Fig. 1); and an inductive rotor (1, Fig. 1) having multiple substantially annular inductive members 50, 54 perpendicular to the axis of rotation of the rotor, wherein the spatial distribution of inductive material of each annular member has a rotational symmetry of at least order one. The annular members may comprise lobes of inductive material, e.g. angularly offset about the rotation axis. For example, the annular members may carry skewed lobes 50’, 54’ which follow a helical line along the surface of the inductive members. Alternatively they may carry substantially arch-shaped lobes (30’, 34’, Fig. 3) bounded by straight parallel edges with bevelled corners (37, 37’, Fig. 3) at lobe ends (38, 39, Fig. 3).