THD Analysis with multicarrier switching for Cascaded Multilevel Inverter with reduced number of switches

Abstract

Multilevel inverters have found a wide place in market for their use in medium and low power applications. This paper proposes a Cascaded Multilevel inverter with unequal sources and with reduced switch count. Multiple switching at each level is obtained by using Sinusoidal Pulse Width Modulation (SPWM) techniques. The SPWM is realized with different carrier signals such as Phase disposition(PD), Disposition Phase Opposition (DPO) and Alternate Phase Opposition Disposition(APOD). THDs are also calculated for different magnitudes of carrier signals.