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 (jω). Based on the principle of complex power calculated from the equivalent circuit identical to that derived from electromagnetic field equations, L d (jω) and L q (jω) 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.