A Modified Quasi-Z-Source Inverter with Enhanced Performance Capability

Abstract

This paper proposes a modified single phase quasi-Z-source inverter (qZSI) with enhanced performance capability. The total harmonic distortion (THD) values of output voltage and current are reduced differently using the unipolar pulse width modulation (PWM) technique. In addition, the voltage gain ability of the circuit is improved with the help of an additional boost switch connected in parallel with the impedance network and power MOSFETs. The employment of the unipolar PWM technique adapted for the qZSI is explained and the operating principle of the proposed circuit with the additional boost switch is described using mathematical expressions. Simulations are carried out to show the effectiveness of the circuit for a determined modulation index using Matlab/Simulink environment. Compared with the classical qZSI topologies, the presented circuit has lower THD and increased voltage gain.