Topology and Modulation of a Novel Fixed-Frequency-Phase-Shift Controlled Soft-Switching Quasi Single Stage Microinverter with LCL Resonant Tank

This paper proposed a novel fixed-frequency-phase-shift (FFPS) controlled isolated quasi single stage microinverter. Distinguished from traditional DAB based microinverter topologies, an LCL-resonant tank is utilized in the proposed topology. Soft switching of all high-frequency switches in this microinverter is achieved by appropriately determining the switching frequency and phase-shift ratio. Owing to the approximate constant-current-source characteristic of LCL tank, an easy-to-implement control strategy has been devised and lead to low THD. Finally, a prototype for the 35Vdc-220Vac application was built in the laboratory and peak efficiency of 96.54% is achieved at 472W. The outcomes verify the feasibility of the proposed microinverter.