A novel H6-type transformerless inverter for grid-connected photovoltaic application

A novel H6-type inverter is proposed for the trade-off solution of common-mode current (leakage current) and conversion efficiency in transformerless photovoltaic (PV) grid-connected energy generation system. A direct power passing path is introduced into the H5 topology to ensure the current flows through less power switches than that in the H5 topology during the operational mode of direct power transfer from the input to output sides. So the conduction loss in the proposed inverter is lower than the H5 topology. The operational principle is analyzed in detail, and some extended topologies with the same idea are given as well. The proposed topology features a fine trade-off between the power loss and the common-mode performance, compared with the famous H5 and Heric topologies. Comparative experimental results of the three topologies are presented with a universal prototype.