A Comparison Study of High-Frequency Isolated DC/AC Converter Employing an Unfolding LCI for Grid-Connected Alternative Energy Applications

A high-frequency (HF) isolated dc/ac converter including an unfolding line connected inverter can be used as the interface between a small-scale alternative energy generation system and the utility line. This paper presents the review of operation of several different topologies of HF isolated dc/ac converters. They are designed for illustration purpose and compared for their performance. It is found that the dual-LCL series resonant dc/ac converter can maintain zero-voltage switching (ZVS) operation for all switches with low line-current total harmonics distortion (THD) and high efficiency. Experimental results on a 500-W prototype converter are included for validation purpose.