Simulation of SPWM based Z-Source Inverter

Abstract

This paper presents a single stage Z-source inverter (ZSI) that can either buck or boost the ac output voltage from a DC supply. This topology overcomes the short comings of the where the output ac voltage is either less or more than the input dc voltage. The ZSI also allows two switches of the same leg to be gated in the circuit thus eliminating the shoot through fault that normally occurs in the traditional converters. This feature of the inverter provides the elimination of dead time in the circuit, thus increasing the reliability and reducing the output distortion. To prove the effectiveness of ZSI in reducing THD, performance of ZSI is evaluated using MATLAB/SIMULINK model developed for ZSI feeding R, RL, Motor load. The simulation results are presented for various modulation indexes and compared with the simulation results of VSI and CSI. The results validate the effectiveness of ZSI over VSI and ZSI. Keywords-Current source inverter, voltage source inverter, Z-source inverter, SPWM, THD.