Theoretical analysis and experimental validation of a novel multilevel inverter topology for renewable energy interfacing applications

This paper presents a new topological structure for symmetrical cascaded multilevel inverters. The proposed circuit consists of cross-connected separate symmetrical DC sources which can generate number of levels equal to that of a cascaded H-bridge topology with reduced number of power switches. It is especially suitable for utility interfacing of renewable energy sources. It also offers the possibility of a transformer less and filter less operation. The working principle of the proposed topology is explained with the help of a single-phase five level inverter. Simulation results are obtained in MATLAB/SIMULINK environment and are verified experimentally on a laboratory prototype. An exhaustive comparison of the proposed topology is made with the classical cascaded H-bridge topology, especially with the considerations of conduction losses and cost-effectiveness. The proposed topology results in the reduction of number of power switches, losses, installation area, and converter cost and thus can be implemented as an effective and efficient power electronic interface for renewable sources of energy with the utility grid. (C) 2012 American Institute of Physics. [doi:10.1063/1.3683515]