Five-phase permanent magnet motor drives for ship propulsion applications

Multi-phase machines are very good candidates for ship propulsion application. In this paper, first a literature survey on the work accomplished in the area of multi-phase, split-phase and dual stator machines are presented. In the rest of the paper, additional degrees of freedom in multi-phase permanent magnet machines are employed to improve the overall performance of the system. Among all, the paper suggests and focuses on four significant features of multi-phase machines. First, the ability of injecting harmonic of currents in the motor and improving the torque production capability is discussed. Second, better torque and flux adjustment in DTC controlled multi phase motor is presented. Third, fault resilient current control of multi phase drive under loss of phases is examined. Finally the possibility of controlling multi motors through a single inverter is pointed out. The five phase permanent magnet motor is considered in this paper as an example. However the concept can be extended to higher number of phases.