Transformerless active power decoupling topologies for grid connected PV applications

Active power decoupling (APD) topologies are well known for improving the reliability of a single-phase inverter by eliminating the need for electrolytic capacitors at the DC-link. In this paper, several APD topologies are analysed for grid connected PV application, where, the common mode leakage currents are one of the main concerns. It is found that few APD topologies can minimize these leakage currents without any modification in the original circuits. The performance of these APD topologies in minimising the leakage currents are analysed and evaluated using the simulation studies. Further, a new transformerless APD topology is derived and its performance is analysed in minimising the leakage current.