A new control method for an interleaved flyback inverter to achieve high efficiency and low output current THD

In recent years, solar energy systems based on microinverter architectures due to its highest power optimization and design flexibility are gaining popularity. The main focus of this paper is on microinverter, particularly the microinverters that are based on the flyback inverter topology. The flyback inverter operating in discontinuous conduction mode (DCM) and boundary conduction mode (BCM) are used more than the others. Control strategies of flyback inverter have different impact on the losses and the efficiency. In the interleaved flyback inverter, it is noted that the turn-off and the gate driving losses under BCM are much higher than DCM. This translates into a significant reduction of the light load efficiency. In this paper based on the loss analysis, a control strategy combing the two DCM and BCM control for the interleaved flyback inverter is proposed to improve the efficiency by reducing switching frequency in the light load current. Finally, simulation results based on an interleaved flyback inverter are presented. It is shown that the proposed control strategy can improve the efficiency and THD of the output current.