Analysis and Control of Switched Quasi-Impedance-Source-Inverter With Superior Boosting Ability for Renewable Energy Applications

Abstract

Impedance-source inverters (ZSIs) are getting more attention in renewable energy generation over conventional inverters due to their inherent boosting ability and shoot-through immunity. However, most of the ZSI expansion abilities are somehow limited by the component stresses and poor performance, particularly at a low modulation index. In this article, a new coupled inductor-based switched quasi-ZSI is proposed to accomplish enhanced boost inversion at a high modulation index. It offers a robust boosting feature even with a very low turns ratio, which significantly reduces the passive circuit element's size. The working principle, steady-state analysis, and the design guidelines for selecting circuit parameters are addressed. The proposed inverter significantly improves the input current ripple with enhanced boosting with appropriate control of the impedance-network active switch. A comprehensive comparative analysis with allied topologies is presented to show the proposed inverter's effectiveness. The superior features offered are more suitable for renewable energy generation from low- and variable-voltage renewable sources, such as solar PV and fuel cells. A laboratory prototype is made for experimental verification. Analytical, MATLAB simulation and experimental results are presented to validate the proposed theory.