An Improved SVPWM Control Technique to Reduce Winding Losses of 9-Phase Induction Motor

The improvement in the linear modulation reduces with increase in the number of phases of the induction machine (IM) by using the multiphase space vector pulse width modulation (SVPWM) control technique. For example, for a nine-phase IM, the linear modulation region is improved by only 1.54% by using nine-phase SVPWM control technique compared to nine-phase sinusoidal pulse width modulation. On the other hand, the octadecagonal SVPWM control technique helps in attaining improved linear modulation region and better harmonic profile compared to nine phase SVPWM control technique. However, the phase voltages and currents consists of lower order dominant harmonics of the order 5
^th
, 7
^th
, 11
^th
, and 13
^th
... In this paper, an improved control technique using vector space decomposition is presented to limit the lower order dominant harmonics in the phase voltages and currents. With the presented control technique, one can choose between the improvement in the linear modulation region and the minimization of lower order dominant harmonic components. To validate the presented concept, experimentation is performed on laboratory prototype of a 9-phase IM.