Novel Symmetric Six-Phase Induction Motor Drive Using Stacked Multilevel Inverters With a Single DC Link and Neutral Point Voltage Balancing

Abstract

This paper proposes a novel six-phase stacked multilevel inverter drive with only one dc source for a six-phase IM with symmetrically placed windings ( $60$ ° apart). Using one dc source allows direct ac–ac conversion and the inverter can feed the power back to the grid at any power factor. This paper presents a systematic approach to use one dc source for the six-phase stacked multilevel inverter fed symmetric IM drive. Here the individual dc supply is realized by series connected (split) capacitors with inherent balancing of the neutral point (dc link capacitor mid point) current within a switching cycle. This also helps in reducing the dc-link capacitor size. To verify the concept experimentally, a six-phase stacked nine-level inverter is developed in the laboratory for a symmetric six-phase IM and it is run with V/f control. Detailed experimental results are presented to validate the concept.