PSEUDO RANDOM CARRIER PULSE WIDTH MODULATION SCHEME FOR THE REDUCTION OF HARMONIC DISTORTION FOR CASCADED H-BRIDGE MODIFIED MULTI LEVEL INVERTER

A pseudo random carrier pulse width modulation (PRPWM) scheme for multilevel power converters, for the elimination of harmonic distortion is presented. This paper also proposes a cascaded H-bridge modified five level inverter topology with less number of switches features a high modularity degree compared to conventional multilevel inverter topologies. PRPWM scheme is optimized using a binary valued genetic algorithm (GA). The proposed optimized PRPWM strategy provides an improved performance over traditional random pulse width modulation scheme for multilevel inverters. The total harmonic distortion (THD) is taken as the performance index for optimization. The proposed scheme for generating optimized PRPWM for modified multilevel inverter is simulated for a three-level and five-level inverter, and experimental results are presented for a five-level inverter.