Extracting formulas of line voltage THD for 7-level inverter with equal DC sources

Abstract

Multilevel Inverters inject lesser harmonics in comparison with common 3-level inverters. However, this amount is notable. THD is a proper index to evaluate the amount of harmonics. Line voltage THD of a 5-level inverter's stepped waveform has been formulated in literature. In this paper, the method of calculating the formulas is developed. So, the formulas of line voltage THD for a 7-level inverter are extracted. It is done to be used for analytical foundation of optimal switching angles as a future work.