THD Minimization in Cascaded H-Bridge Inverter using Optimal Selective Harmonic Elimination

Cascaded structured multilevel inverters are gaining lot of importance due to their simple structure and easiness in implementation. In this paper, the optimum selective harmonic elimination method is employed for a nine level inverter to suppress the selected lower order harmonic, which reduces the total harmonic distortion of the inverter considerably. The Newton rapson algorithm is employed in finding the switching angles that minimizes certain lower order harmonics. The order of the harmonics that are eliminated are third, fifth, and seventh harmonics. All the simulation results included for a nine level inverter using SIMULINK.