Extended Range Efficiency Optimization Control of the Flyback Based Micro Inverter

This paper derives the rigorous mathematical model of the first state converter in a single-phase micro-inverter which is used in household solar generation to extend the soft switching range and improve the overall power efficiency. The current in the flyback converter is discontinuous with variable switching frequencies and peak current references for skipped valley switching, regulated by the instantaneous power generated and the pre-set switching frequency boundary, which is determined by the electrical/thermal performance of the power semiconductor and the transformer. Simulation and experimental results show the semiconductor is able to switch on at specific valleys. The peak efficiency is 94.7% at 75% of the power rating and 92.7 % at light load.