Multi-mode control for photovoltaic grid-connected interleaved flyback micro-inverters to achieve high efficiency in wide load range

Abstract

Boundary Conduction Mode (BCM) and Discontinuous Conduction Mode (DCM) control strategies are widely used for the flyback micro-inverter. BCM and DCM control strategies are investigated for the interleaved flyback micro-inverter concentrating on the loss analysis under different load condition. These two control strategies have different impact on the loss distribution and thus the efficiency of the flyback micro-inverter. Based on the loss analysis, a new hybrid control strategy combing the two-phase DCM and one-phase DCM control is proposed to improve the efficiency in wide load range by reducing the dominant losses depending on the load current. The experimental results verified the benefits of the proposed control.