Single-Stage High-Frequency-Link Split-Phase Microinverter With High Voltage Gain Based on Buck-Boost AC Chopper

This paper proposes a novel single-stage high-frequency link (HFL) split-phase microinverter. It incorporates two buck-boost ac choppers to form an innovative secondary-side cycloconverter, enabling split-phase output with double the voltage gain compared to conventional topologies. Therefore, the required turns ratio for the high-frequency transformer (HFT) can be halved, resulting in high efficiency and low voltage stress. The microinverter supports split-phase output using a two-winding HFT, while retaining VSI characteristics for both grid-tied and islanded operations. A corresponding soft-switching modulation and dual-mode control strategy are also introduced. Experimental validation using a 600-W prototype demonstrates the efficacy of the proposed topology, achieving a peak efficiency of 96.5%.