Optimal Current Interleaving Control for Interleaved Flyback Microinverter

The flyback microinverter presents several advantages, such as compact size and input-output isolation. It is particularly well-suited for distributed photovoltaic power generation systems of small to medium scale. By leveraging the characteristics of the flyback converter, expressions for the grid current in relation to the frequency and duty cycle of the main switch during discontinuous conduction mode (DCM) are derived. Furthermore, an optimal current interleaving control method is proposed for the flyback microinverter by introducing an overlap factor. This method minimizes the overlapping areas of the secondary currents and the current stress experienced by switches in the full-bridge inverter, thereby reducing high-order harmonics and enhancing the quality of the grid current. Finally, a simulation model was established in PLECS to validate the efficacy of the proposed algorithm.