A Stacked Multilevel Inverter With Single DC Link for Open-End Winding Induction Motor Drive With Zero-Voltage Switching and Common-Mode Voltage Elimination

A switching-state selection scheme for a five-level stacked multilevel inverter for open-end winding motor drive is presented in this article. Using the proposed scheme, converter can be operated with a single dc supply and with zero common-mode voltage. In addition, the switching transition of high-voltage switches occurs at zero-voltage conditions. The degree of freedom provided by the redundant switching-states and voltage vectors of the inverter topology is utilized to design the modulation scheme. The proposed switching-state selection leads to inherent capacitor balancing without using any extra sensors and fundamental frequency switching of the high-voltage switches of the topology. The modulation scheme uses triangular carrier comparison and, hence, avoids the complexity of subsector identification and dwell time calculation. Half-wave symmetry in output waveforms is ensured by maintaining synchronous sampling with constant samples per fundamental cycle. The inverter topology and the effectiveness of the state selection scheme are experimentally validated on an open-end winding induction motor drive, and experimental results showing steady-state and dynamic operations are presented.