Comparison of SiC and GaN devices for front-end isolation of quasi-Z-source cascaded multilevel photovoltaic inverter

Abstract

The wide band-gap Silicon Carbide (SiC) and gallium nitride (GaN) materials based semiconductor devices have attracted tremendous attentions in modern power electronics applications. They provide much higher switching frequency and higher junction temperature than silicon power devices, thus to significantly decrease the system volume and weight, especially on passive components. In this paper, the characteristics of the SiC and GaN materials and devices are overviewed. A front-end isolated quasi-Z-source cascade multilevel inverter (qZS-CMI) based Photovoltaic (PV) power system is proposed to insulate the PV array from high voltage grid and make possible of PV grounding, thus to enhance the system reliability and safety. The SiC and GaN devices applied to the front-end isolation of qZS inverter module are compared. Experimental results verify the proposed front-end isolated qZS-CMI and comparison results, demonstrating a competitive solution for the future development of such inverters.