Soft Switched Common Ground Transformerless Single Phase PV Inverter

Soft-switching techniques are employed in compact photovoltaic transformer-less inverters (TLIs) which operates at high switching frequencies. Inverters which comply to recent technical standards like IEEE1547 needs to have a greater power factor operation range so that it can support the utility grid during sag and swell conditions. However, many of the existing soft-switched TLIs are meant to work at unity power factor only. Some of the recently proposed H-bridge derived TLI topologies which support full power factor (FPF) operation is built with more number of auxiliary switches and this increases the complexity of the inverter. In this paper a zero-voltage transition (ZVT) common ground (CG) transformer-less inverter is proposed where soft-switching is achieved for FPF operation with only four additional auxiliary switches. This scheme ensures zero voltage turn-on and turn-off for the main switches and zero-current turn-on for the auxiliary switches.