Asymmetrical Twelve-Phase Induction Starter/Generator for More Electric Engine in Aircraft

In this paper, a 12-phase asymmetrical induction machine is proposed as embedded starter/alternator connected to the high-pressure shaft of an open rotor jet engine. The main focus of the paper is on the modeling and control of the multiphase machine in order to verify its operation, including overload capabilities and post fault operations. The machine control uses a direct flux vector control scheme based on a multi three-phase approach, where each three-phase winding set is independently controlled. In this way, the fault tolerant behavior of the drive system is improved. The proposed solution has been experimentally validated with a multi-modular power converter and a reduced scaled machine prototype (10 kW, 6000 rpm). The overload capability has been verified in generation mode for different speed values and torque up to the 150% the rated value. The sudden transition between healthy and faulty modes is reported for open-phases fault.