Performance Improvement of a Nine-Phase Induction Machine using Octadecagonal SVPWM Control Technique

It is well known that multi-phase induction machine drives (IMD) are best suitable for high power application compared to the conventional 3-phase IMDs. However, with the implementation of multi-phase space vector pulse width modulation (SVPWM) presented in the literature, improvement in the linear modulation region is less significant as the number of phase increases. To overcome the abovementioned limitation, this paper proposes an octadecagonal SVPWM control technique for a nine-phase induction machine. With the implementation of octadecagonal SVPWM control technique, the linear modulation region is improved by 26.03% compared to nine-phase sinusoidal pulse width modulation and 24.2S% compared to nine-phase SVPWM. In addition, the lower order dominant time harmonics in the air-gap flux are eliminated even though the phase currents of nine-phase induction machine consist of lower-order harmonics. The absence of lower-order dominant harmonics in the air-gap flux results in reduced torque pulsations of the IMD. ANSYS Maxwell simulation and experimentation results are presented to validate the proposed control technique.