Optimal flux reference to operate a five-phase induction machine under two open-phase fault condition

Electrical drives are largely adopted in industry and in the last years, thanks to the increased awareness towards the environment, they are spreading as a means for transport. The most common electrical machines are three-phase and their construction is well known. However, for a three-phase machine the first fault on one phase of either the machine or the inverter implies the impossibility to develop a torque causing the stop of the machine. Multiphase machines among all the different advantages allow to keep operating until three phases are healthy. For this reason, these types of machines are spreading in all the applications for which the continuity of service is necessary. In this paper a five-phase induction machine is considered. In particular, for this machine, the working conditions with two faulted open phases is studied and the optimal reference for the machine flux is evaluated together with the maximum allowable torque. Both the cases of adjacent and non-adjacent faulted phases are analyzed and the results are proven by means of numerical simulations.