Design and analysis of an improved single-phase QUASI-Z-source inverter

Abstract

In recent years, the traditional power inverter systems have been replaced by the modern impedance source inverter (ZSI) circuit topology which became highly popular due to many benefits such as voltage boosting ability, reduced cost, flexibility, and, less sensitivity to electromagnetic noises. This paper presents an improved single-phase quasi-Z-source inverter (qZSI) circuit model. The input inductor of the qZSI circuit has been replaced by a switched-inductor (SL) configuration which is integrated into DC power source and impedance network. The proposed circuit can make use of the stored DC power with the help of the SL form within the shoot-through time interval. In comparison with the conventional qZSI topology, the proposed model increases the boost factor of the qZSI circuit significantly for the same shoot-through time. In addition to that, the circuit draws continuous input current and shares common ground with DC power source. The operation principle is analyzed with the help of the mathematical equations and simulations are carried out using Matlab/Simulink environment. A laboratory prototype is realized to validate the proposed circuit. Simulation and experimental results are presented to illustrate the performance of the proposed inverter topology. The presented circuit model is open to new developments and can be used for low power applications such as photovoltaic (PV) and fuel cell systems.