Design and Analysis of Double Fed Interior Permanent Magnet Machines for Traction Applications

This paper investigates the electromagnetic performance characteristics of a double-fed interior permanent magnet machine (DE-IPM) designed using 2010 Toyota Prius IPM Machine specifications. The proposed machine accommodates both the armature and field windings in the stator. These windings are fed by separate inverters to regulate the main flux. Therefore, depending on the torque requirement, one of the inverters can simply be open-circuited without causing any failure due to the coupling between armature and field windings. Thus, high-torque at constant torque region and high-power at constant power region can be achieved simultaneously. In order to reveal the merits and demerits of the proposed topology, the no-load, full-load, and flux-weakening performance characteristics of the DE-IPM machine have been compared with those of its conventional (single-fed) counterpart. It is revealed that the DE-IPM machines exhibit improved flux-weakening performance, particularly higher torque and hence higher power in the constant torque operating region.