Contribution to Offline Measurements of PMSM and SyRM Inductances

The measurement of synchronous inductances for three-phase permanent-magnet (PM) machines is usually performed by means of offline tests connecting the stator windings in different single-phase configurations. A test campaign conducted on different machines has demonstrated that the inductance measurement depends on both the stator winding connection scheme and the rotor position. As a result, a new perspective is provided on the generally adopted methodology for offline measurements of synchronous inductances. In particular, this paper highlights the influence of the connection schemes on the inductance values, using several surface-mounted PM-synchronous and synchronous-reluctance machine examples. This study covers both machines equipped with distributed windings and fractional-slot-concentrated windings.