Design and analysis of impedance source based asymmetric inverter for PV application

Abstract

A novel Impedance source seven level Asymmetric Multilevel topology for PV system is presented here. It comprises of a Quasi Z source network and Asymmetric Multilevel Inverter (QZ-AMLI) to synthesize better quality output with low THD. Quasi Z Source Converter (QZSC) with large voltage gain provides a positive boost voltage to an asymmetric multilevel inverter. Asymmetric structure offers large output levels with a smaller number of switches and input sources. QZS network parameters provide a regulated DC supply to the Asymmetric Multilevel inverter (AMLI). DC input magnitude of the inverter is decided by an algorithm. Switching signals are applied in proper sequence to generate required magnitude at the AC output. Regulated DC output voltages of 16V and 32V are obtained at the output of QZSC1 and QZSC2. 7 level inverter output with a magnitude of 48V is obtained by simulation using Matlab /Simulink. The system ensures lower switching losses, reduced gate drive circuitry and improved harmonic profile. Reduced switch and filter requirements lessen the cost of the system.