An electric machine equipped with n stator phases is characterized by a set of n × n phase inductances as concerns the stator section. In the case of nonuniform air gap, these inductances vary as the rotor moves. For their numerical determination as
functions of the rotor position an accurate computation algorithm is proposed in this paper based on winding function theory. For
permeance function identification, a numerically efficient method is employed based on the magnetostatic finite-element analysis of
only three appropriately simplified machine models. In the presence of a field circuit, computation of mutual inductances among
it and stator phases is also covered with the same approach. An extension of the method to permanent-magnet machines is also
presented. Results are assessed on a six-phase synchronous generator prototype equipped with either a salient-pole wound-field
rotor or with an interior permanent-magnet rotor.
