Modified Field Oriented Control for Fail-Operational Multi-Phase Induction Motor Drives

Recently, multiphase machines have gained worldwide attention from the research community and industry for their applications in the electric ship propulsion, electric transports, more-electric aircrafts and for those particular loads that require continuous operation of the machine after one or more phases become open-circuited. A fault can be due to the loss of one of the leg transistors in the voltage source inverter, or be internal to the machine, affecting one of the phase windings. Multiphase machines can continue to operate even in the case where more than one phase is open-circuited, while for a three-phase machine, post-fault operation is possible only if one phase is opened and the star point of the machine is connected to the dc mid-point of the inverter.In this papers the modeling and control of a five-phase induction machine with the field oriented control technique are presented; then, an algorithm for the post fault operation when one stator phase is open-circuited has been proposed and the results of the simulations, carried out with different load torques and reference speeds, have been reported and discussed.