A Novel Approach for Measuring Phase Resistance and Inductance in Double-Rotor Permanent Magnet Axial Flux Machines

Measuring phase inductances and resistances in 3-phase axial flux machines with double-rotor, single-coreless stator configurations, surface-mounted permanent magnets, and Y-connected windings presents significant challenges, particularly when star point access is unavailable. To address these challenges, this paper introduces a novel method for experimentally measuring line-to-line resistances and inductances using an LCR meter, followed by the derivation of a transformation matrix to convert these measurements into per-phase values. This approach overcomes the challenges posed by the absence of star point access and ensures accurate measurement of low inductance values. The key contribution of this work is the experimental derivation of phase inductances from line-to-line measurements, along with the development of a transformation matrix that enables precise parameter determination. The results demonstrate the effectiveness of the proposed method in overcoming the challenges associated with Y-connected windings lacking star point access.