On advantages of multi-phase machines

In this paper, a literature survey on the work accomplished in the area of multi-phase, split phase and dual stator machines will be presented. Although, reducing torque pulsation caused the early interest in dual stator, split phase and multiphase machines, there are other important features that this kind of machines present to the drive designer. Additional degrees of freedom in multi-phase machines are employed to improve the overall performance of the system. They can be used to improve the reliability of a multiphase system, to enhance the torque production capability of the machine by injecting harmonics of current or to control multi-motors from a single inverter. Also, the presence of more space voltage vectors, allows better adjustment of torque and flux in a direct torque controlled system.