Comparative Analysis of Optimal and Fixed Input DC Sources with Selective Harmonic Elimination Pulse Width Modulation

Harmonic contents in the output voltage of the multilevel inverter (MLI) affects the performance of different appliances and decreases the reliability of the system. Selective harmonic elimination pulse width modulation (SHEPWM) technique based Bio-inspired intelligent algorithms (BIAs) are found superior to eliminate the undesired lower-order harmonics and lower switching losses. To control the fundamental at the desired level and eliminate the undesired harmonics, mainly two approaches are utilized i.e. fixed input DC sources and optimal input DC sources. In this paper, a detailed comparative analysis is performed among the aforementioned techniques for harmonic elimination. The 5-level inverter is considered and PSO algorithm is applied for the calculation of optimized switching angles for both cases. The Simulation results show that in optimal input DC sources, the fundamental voltage is accurately regulated for each modulation index with an increased number of elimination of lower-order harmonics over a wide range of modulation indexes and achieved lower THD in comparison to fixed input DC sources.