Optimized switching scheme of cascaded H-bridge multilevel inverter using PSO

The paper uses particle swarm optimization (PSO) to determine the optimum switching angles of cascaded H-bridge multilevel inverter (CH-MLI) so as to produce the required fundamental voltage and reduce the harmonic content. This is done by solving the transcendental equations characterizing the harmonic content. The validity of the proposed method is verified through simulation studies for three-phase, five-level CH-MLI. To compare the results obtained using PSO, the simulation studies have been extended for three-phase, five-level CH-MLI using sinusoidal pulse width modulation (SPWM). The results obtained using PSO are found superior as compared to SPWM in terms of total harmonic distortion at different modulation indices.