Low-Voltage Ride-Through Capability of Flyback Inverter Under BCM Operation for AC Module Applications

Under voltage rise/drop conditions, grid-connected distributed generation systems have to be disconnected from the grid. However, due to the increasing number of grid-connected PV systems, the future photovoltaic (PV) systems should become more active and support low-voltage ride-through (LVRT) capability. The aim of this paper is to show a new advantage of the flyback inverter under boundary conduction mode (BCM) for supporting LVRT capability without using any auxiliary control system and any limitation in designing of the parameters. The detailed operation of the flyback inverter under increasing and decreasing conditions of the grid voltage for BCM operation are presented. Finally, simulation results based on the flyback inverter under grid faults are demonstrated. The results elucidate that the flyback inverter under BCM operation can support LVRT capability for Ac module application in distributed generation systems, without any limitation in parameters design and any additional control system.