A current shaping method for PV-AC module DCM-flyback inverter under CCM operation

In the grid interconnected photovoltaic power generation system including PV-AC module system, the output current have to be sinusoidal synchronized with the grid voltage. Concerning the voltage-controlled current source modification requirement and the characteristics of flyback topology, boundary or discontinuous conduction mode operations are suitable for the PV-AC module flyback inverter. However, the flyback inverter can be operated in continuous conduction mode (CCM) due to its operating conditions in spite of it is designed to operate under boundary or discontinuous conduction mode. Unfortunately, it causes unintended distortion to output current. In this paper, a current shaping method to reduce the output current distortion for the DCM-flyback inverter is proposed. Even though the flyback inverter operates under CCM, the output current distortion can be reduced by the unfolding H-bridge switching technique.