Fault tolerance performance of dual-inverter-based six-phase drive system under single-, two-, and three-phase open-circuit fault operation

Considering that so far all studies regarding multiphase drives fault tolerance performance have been carried out making use of conventional two-level inverters, this study discusses the fault tolerance performance of a six-phase drive system based on a dual inverter under single-, two-, or three-phase open-circuit fault. Aiming applications where simplicity and low computation efforts are required and fast dynamic response is not imperative, an open-loop volts/hertz (V/f) compensation strategy is discussed in order to keep the rated operation even after the occurrence of the fault, assuring the maintenance of sinusoidal flux. The six-phase machine mathematical model after the fault is detailed and utilised to elaborate the compensation strategy. Simulation and experimental results show the validity of the discussed solution and its feasibility.