A multilevel inverter fed IM drive with dodecagonal voltage space vector structure using a single DC source with linear modulation range near to base speed

A fifth and seventh order harmonic elimination scheme for IM drive with a multilevel dodecagonal voltage space vector structure using a single DC source is proposed in this work. Single DC source requirement makes four quadrant operation of the drive system simpler compared to the multilevel do-decagonal structures presented in literatures before. The space vector structure consists of six concentric dodecagons, combining the advantages of multilevel operation as well as dodecagonal structure. The topology consists of a three-level flying capacitor (FC) inverter cascaded with a capacitor fed H-bridge (CHB) inverter. The FC inverter operating at high voltage switches in a quasi-square wave mode whereas the CHB inverter operating at a lower voltage switches at high frequency to remove the harmonics generated by the FC inverter. Switching losses are low, both in the FC and CHB inverters. Experiment results for open-loop V/f operation are included in this paper showing the effectiveness of the drive scheme.