Non-Saliency of Interior Permanent Magnet Hybrid Excitation Machine

Abstract

It is a general perception that the interior permanent magnet machines will have different values of inductances along d-axis and q-axis and hence they are salient pole machines. Though it is true in most of the cases, some interior permanent magnet machines may turn out to be non-salient pole machines. Hence an accurate modeling of magnetic equivalent circuit is very much required in order to estimate the inductance values along d-axis and q-axis. A hybrid excitation machine with an interior configuration of permanent magnets and field winding is proposed in the literature. Though it appears to be a salient pole machine from rotor configuration view point, the actual analytical inductance analysis on this machine proves that it is a non-salient pole machine. A simpler analytical approach is carried out through approximate linear magnetic equivalent circuit. The analytical analysis is validated with analysis carried out through FEM software.