Fault-tolerance of five-phase induction machines with mixed stator winding layouts: Torque ripple analysis

The mixed winding layouts proposed in this paper are obtained by combining double and triple layer (DTL) windings in stator slots. Previous work has touched upon on the ability of three-and five-phase induction machines (IMs) with mixed winding layouts to produce torque with less ripple contents. However, their advantage when operating under open-circuited faults is yet to be comprehensively reported. This paper presents the fault-tolerant ability of Five-phase Induction Machines (FPIMs) with mixed winding layouts to produce torque with less ripple contents. The windings are designed as 2-pole and chorded with one slot, thereafter referred to as "DTL-14/15" and when chorded with two slots, thereafter referred to as "DTL-13/15. The magnetic conditions in the FPIMs are analyzed using Finite Element Method (FEM). The results evidenced that the FPIMs with the proposed DTL-14/15 and DTL-13/15 chorded coils reduced the torque ripple by a margin of about 60 % while operating with open-circuited faults respect to FPIMs with conventional double layer (DL) winding of the same coil span and operating under the same conditions. The results also prove that there is a great correlation between FEM (simulation) and experimental results.