Design and Assessment of DC-DC Interleaved Flyback Stage for Module-Integrated PV Microinverters

Microinverters are typically integrated with individual solar photovoltaic (PV) modules to enhance system performance. This paper presents the design and evaluation of an interleaved flyback DC-DC converter for microinverters in a methodical approach. The flyback converter is selected for its advantages, including a reduced component count and a simplified architecture. Additionally, it provides electrical isolation, meeting grid code requirements, and offers high voltage gain, making it suitable for a wide range of input voltages. The time-interleaved operation of the DC-DC flyback stage, utilizing multiple parallel switching phases, effectively reduces ripple current, minimizes component stress, and improves power density. An active clamp circuit is incorporated to recover leakage energy. The operational principles, including all modes of operation, are thoroughly explained. The complete design is presented with relevant mathematical formulations and validated through software simulations.