A Double-Gain 5-Level Grid-Connected DC-AC Converter

This paper suggests a high-efficiency switched-capacitor based transformer-less 5-level grid-tied inverter that operates based on series-parallel charge/discharge of capacitor-cells. The structure is capable of limiting the capacitors' impulsive charging current. This structure employs the Peak Current Control (PCC) technique to generate the switching pulses, and control the active/reactive power flow by properly controlling the injected current into the grid. The leakage-current issue is resolved, due to presence of Common-Ground-Point (CGP). This feature along with the ability of working in both buck or boost modes, makes the suggested converter suitable for PV-applications. The multi-step waveform leads to less-THD, and compact filter-size. The correct function of suggested converter has been affirmed by simulation results, for a 520W prototype.