Comparison of operating curves of five-phase and three-phase induction machines of same size

The steady state operating curves of three design variants of a five-phase induction machine are assessed and compared to a standard three-phase induction machine of the same size which is taken as the basis for the comparison. The performance in terms of torque, power factor, stator current and efficiency are analyzed for different load conditions. The operating curves are determined by means of an electrical model that includes the effects of the third-harmonic component of the airgap induction, iron saturation and magnetic losses as well. The electrical parameters used in this model are obtained analytically. Based on the data of the machines considered, it is shown that five phase machines can have a slightly better performance than an equivalent three-phase machine, even when they have less conductor volume in the stator and rotor windings. The results also show that five-phase machines considered can present a higher peak torque and thus a better overload capacity.