A High Gain Z-Source Converter with Reduced Device Count for Distributed PV System

Abstract

Interfacing low-voltage (LV) sources such as solar PV, fuel cells, DC microgrids, and switch mode power supplies requires high gain DC-DC converters (SMPS). Nevertheless, a number of high gain topologies presented in the literature have drawbacks such as limited voltage boosting factor, increased device voltage stress, inability to manage wide input voltage changes, increased device count, discontinuous input current, etc. Keeping the aforementioned constraints in consideration, this article proposes a modified high gain converter to overcome the concerns. The Z-source (ZS) converter is modified by incorporating two voltage multiplier cells (VMC) to produce high gain while minimising voltage stress and device count. Moreover, the converter provides higher conversion efficiency at lower duty ratios while drawing continuous input current and sustaining output voltage under significant input changes, which is desirable for an SPV-interfacing converter. The implemented topology’s performance is comparable to recent topologies. In addition, thermal modeling of the proposed converter is performed in PLECS to determine thermal loading under steady-state operation. Eventually, simulation results validate the theoretical assertions.