Research on common-mode leakage current for a novel non-isolated dual-buck photovoltaic grid-connected inverter

Abstract

The inhibition of common-mode leakage current is the key problem to be solved in non-isolated photovoltaic grid-connected inverter (NPGCI). To eliminate the common-mode leakage current of dual-buck grid-connected inverter, a novel non-isolated dual-buck photovoltaic grid-connected inverter (NDPGCI) topology is proposed in this paper. Meanwhile, a unipolar sinusoidal pulse width modulation (USPWM) strategy that can make the common-mode voltage constant is presented. Then, operating modes and common-mode leakage current of NDPGCI are analyzed, which show that NDPGCI modulated by USPWM has advantages of no shoot-through problem, three-level output characteristic and high reliability, as well as common-mode leakage current elimination. Finally, the experimental results verified the correctness of NDPGCI.