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.