A Single-Stage High-Frequency-Link Microinverter with Split-Phase Structure

Abstract

High-frequency link (HFL) inverters have drawn a lot of attention as a promising structure, owing to their high transformer utilization factor, bidirectional energy transfer, and easy implementation of soft switching. However, the use of HFI structures in split-phase systems is rarely studied. Therefore, a novel single-stage high-frequency link microinverter with a split-phase structure is proposed in this paper. The proposed microinverter can provide two different output-voltage levels matching the single-phase three-wire power system. The output voltages of the two phases can be balanced naturally without dedicated control. It has grid-forming capability, which can be used in both grid-connected applications and islanded applications. With a secondary-side modulation (SSM) strategy, zero-voltage switching (ZVS) can be realized in the proposed microinverter. A 600-W prototype is established, and the experimental and simulation results verify the proposed microinverter.