Elimination of Harmonics in a Multi-Level Inverter with Unequal DC Sources Using the Homotopy Algorithm

This paper focuses on elimination of harmonics in a multi-level voltage-source inverter with unequal DC sources. The main objective of harmonic elimination is to reduce the total harmonic distortion (THD) in the output voltage waveform. The basic concept of this reduction is to eliminate specific harmonics, which are generally the lowest orders, with an appropriate choice of switching angles. Homotopy algorithm is used to solve the transcendental equations for finding the switching angles. This algorithm can be used for any number of voltage levels without complex analytical calculations. Simulation results verify the validity and effectiveness of the proposed algorithm.