Single-stage controlled PV micro-inverter with symmetrical phase-shift modulation

This paper focuses on digital signal processor based technique to achieve a grid-connected photovoltaic power generation system with single-stage controlled algorithm. The researched system is consists of a full-bridge high-frequency DC/DC converter with the proposed symmetric phase-shift modulation to achieve the ZVS switching function, and a DC/AC inverter which can have two operating methods depending on the applied situation, respectively, for the two-stage DC-AC inverter and a single-stage DC-AC inverter. It replaces the traditional two stages of independently control algorithms with the integrated single-stage control to obtain high conversion efficiency. Finally, a prototype of 350W system with the maximum power point function is settled to verify the proposed idea.