Effect of Phase Shift on Inductance and Short-Circuit Current in Dual Three-Phase 48-Slot/22-Pole Permanent-Magnet Machines

Abstract

This article investigates the effects of phase shift on the inductance and short-circuit current (SCC) in permanent-magnet (PM) machines with dual three-phase winding configurations. First, the relationship between the phase shifts and slot/pole combinations, for the dual three-phase winding configurations, is discussed. Second, analytical expressions of the inductance are derived for the 48-slot/22-pole PM machines with different phase shifts based on the winding function theory. Afterwards, the SCC amplitude of different phase shifts is comparatively analyzed. The investigation reveals that the 7.5° and 30° configurations have great significance to improve the self-inductance value. Thereby, the 30° configuration has comparable SCC amplitude compared to the 7.5° counterpart, while being lower than the 15° configuration one. Moreover, the 30° configuration exhibits lower eddy-current loss and preferable torque performance than its counterparts. Furthermore, the finite-element method is used to calculate electromagnetic performances for evaluation. Finally, some experiments on the prototype machine are carried out for validation.