A New Single-Phase Single-Stage Photovoltaic Grid-Tied Inverter with Leakage Current Eliminating and Power Decoupling

Common-mode leakage current and double-line-frequency power oscillation are two major challenges of non-isolated single-phase grid-tied inverters. To overcome these two challenges, this paper proposes a new single-phase single-stage inverter for photovoltaic grid-tied systems, which consist of two switches, three capacitors, two inductors, and one diode. The proposed topology allows the negative pole of the photovoltaic panel to be directly connected to the neutral line of the utility grid so that the common-mode leakage current is eliminated completely. Then a mixed modulation strategy combining pulse width modulation and pulse frequency modulation is proposed to suppress the double-line-frequency power oscillation. Two of the capacitors are utilized to handle the power difference between the AC and DC sides, and the other is utilized to implement zero voltage switching. The proposed inverter is also capable of outputting reactive power. The validity of the proposed inverter is verified by simulation.