An improved performance of cascaded multilevel inverter with single DC source by employing three-phase transformers

Abstract

In reply to the increasing demand for high power inverter units, multilevel inverters have been attracting in favor of academia as well as industry in the recent decade. Among the mature multilevel converter topologies, cascade multilevel H-Bridge inverter is promising one which is an alternative for grid-connected photovoltaic/ wind-power generator, flexible alternating current systems and motor drive application. The CMC (cascade multilevel converter) can flexibly expand the output power capability and is favorable to develop. Present paper elevates a new structure of CMC with a low frequency three-phase transformers and a single DC power source. Comparing with conventional CMC this new CMC uses less number of components for same number of output levels. As three phase transformer was employed harmonic components of the output voltage and switching losses can be diminished considerably. Computer aided simulations was performed through matlab/simulink and simulation results for seven and nine level are presented to verify the performance of proposed cascade multilevel inverter.