ZVS Analysis of DAB Based Single Stage Grid-Connected Microinverter

The rapid expansion of renewable energy adoption has intensified the research interest in grid-connected microinverters. Compared to traditional two stage topologies, single-stage topologies offer huge advantages, potentially achieving high efficiency and power density through reduced component count and simplified structure. This paper presents a novel single-stage topology based on the dual active bridge (DAB) converter. We provide a comprehensive theoretical analysis of ZVS conditions across four distinct operating modes for all switches. The analysis includes the verification of the boundary condition continuity and the complete characterization of ZVS regions under the varying voltage conversion ratios. Detailed simulation validates the theoretical analysis regarding the ZVS operational boundaries under the DC/DC DAB converter. Also, simulation for the single-stage topology is conducted to verify its effectiveness.