Reduced harmonics in a seven level asymmetric multilevel inverter with aperiodic DC sources

Abstract

Nowadays, multilevel inverters are mostly used in industrial applications. Cascade H-Bridge structure is one of the multilevel inverter topology for converting DC to AC. While achieving this operation, if DC sources used with different ratios, it is called Asymmetric Multilevel inverter. Lots of different fault types can be accrued in the operation of inverter. One of this fault is caused by decreasing of the DC source. When this fault occurs, the output wave of the inverter will deviate from the sinus form due to harmonics. To correct this situation, it is necessary to make changes to the multi-carrier PWM modulation used to generate the switching signals of inverter. In this study, it is aimed to reduce the total harmonic distortion in the output wave by using multi-carrier PWM modulation in case of decrease in one or both of the DC sources in the seven-level Asymmetric multi-level inverter.