Experimental Comparison of Two-Level Full-SiC and Three-Level Si–SiC Quasi-Z-Source Inverters for PV Applications

Abstract

The paper presents a comparative study of two solar string inverters based on the Quasi-Z-Source (QZS) network. The first solution comprises a full-SiC two-level QZS inverter, while the second design was built based on a three-level neutral-point-clamped QZS inverter with Silicon based Metal−Oxide−Semiconductor Field-Effect Transistors (Si MOSFETs). Several criteria were taken into consideration: the size of passive elements, thermal design and size of heatsinks, voltage stress across semiconductors, and efficiency investigation. The Photovoltaic (PV)-string rated at 1.8 kW power was selected as a case study system. The advantages and drawbacks of both solutions are presented along with conclusions.

Keywords

• DC–AC converters
• efficiency
• neutral-point-clamped inverter
• PV applications
• PV inverters
• PV systems
• quasi-z-source
• two-level inverter
• three-level inverter
• converter topologies