Performance of nine-switch inverter-fed asymmetrical six-phase induction machine under machine and converter faults

This paper investigates the performance of an asymmetrical six-phase induction machine fed by a six-phase nine-switch voltage source inverter under both healthy and open motor phase cases. In the literature, the nine-switch inverter topology is proposed as a suitable reduced switch-count converter topology for six-phase drives, where each pair of phases share the same converter leg. First, a brief summary about this topology along with its limitations are introduced. The six-phase drive system topology is then investigated under both inverter and machine open-circuit faults. Conventional rotor field oriented controller is employed as a controller platform for such a drive. Optimal current control is used under open phase conditions to ensure a certain optimization criterion, namely, minimum stator copper loss or maximum torque production. The system is investigated through a simulation study using MATLAB/SIMULINK.