Enhanced soft-switching strategy for flyback-based microinverter in PV power systems

Flyback topology has been widely used to construct modular power conversion for solar photovoltaic (PV) grid-tied systems, which creates a parallel interconnection infrastructure and is considered as the most straightforward way to cope with the harmful mismatch effects among PV modules. The challenge becomes the conversion efficiency and system reliability to be competitive with traditional system configurations. This study proposes a comprehensive solution to overcome the present problem, which optimally integrates the technology of resonant circuit, adaptive modulation scheme, and active clamping to enhance soft-switching capability and system efficiency. The effectiveness of theoretical analysis, circuit design, and modulation scheme is analysed by simulation and verified by experimental evaluation. The California Energy Commission efficiency is tested and shown as 97.4%.