Analytical Prediction of Operational Inductances in Surface Permanent-Magnet Synchronous Machine

This paper describes theoretical work about operational inductances of surface PM synchronous machines. An analytical method is presented to predict the direct- and quadrature-axis operational inductances originating from standstill test method of synchronous machine. The operational inductance
$L_{d, q}(p)$
implies the frequency-dependent synchronous inductance
$L_{d, q}(j\omega)$
. Based on the principle of complex power calculated from the equivalent circuit identical to that derived from electromagnetic field equations,
$L_{d}(j\omega)$
and
$L_{q}(j\omega)$
are presented. In addition, the analytical model is applied to both ring magnet and arc magnet constructions. The time harmonic finite element results validate the analytical prediction.