Investigation of a Multiphase Winding Arrangement for Mitigating Short-Circuit Fault Currents

Abstract

Electric machines can experience various types of short-circuit faults when the insulation fails. Inter-turn short-circuit (ITSC) faults can be particularly hazardous for surface-mounted permanent magnet (SPM) machines. This paper proposes a multiphase winding configuration to mitigate ITSC fault currents. With the proposed winding arrangement, ITSC faults become phase-phase faults and can be blocked by the drive. Alternatively, control actions can reduce the fault current and allow the machine to continue normal operation. Short-circuit faults between turns are evaluated using finite element analysis for an example 12-slot, 10-pole SPM machine. The case study demonstrates that the proposed winding arrangement reduces the short-circuit fault from 5400% of the nominal current to 46%, in some cases, even without any adjustment of the control. Additionally, adjusting the voltages supplied to the affected phases can further reduce the short-circuit current to 10.5% of the nominal current with a negligible impact on the torque.