H6 Non-isolated Full Bridge Grid-connected PV Inverters With Low Leakage Currents

In order to meet the limit for common-mode leakage currents in grid-connected photovoltaic(PV) generation systems,a H6 non-isolated full bridge PV grid-connected inverter is proposed.In the power processing period,the grid-tied current flows through three power switches during one of half line cycles,while flows through only two power switches during another half line cycle.As a result,the conduction losses are reduced and the heat-stress balance is benefited with the proposed H6 topology,comparing with the H5 topology.The operation mode of the proposed topology is analyzed in detail and another three topologies of the H6 non-isolated full bridge grid-connected inverters has been derived.The power losses and costs are fairly compared among the H5 topology,Heric topology and the H6 topology.Finally,both of the conversion efficiency and common-mode performance of these topologies are compared with a universal prototype inverter rated at 1 kW.The experimental results show that the efficiency of the proposed H6 topology is higher than that of the H5 topology,while slightly being lower than that of the Heric topology.And the common-mode performance of the H6 topology is superior to that of Heric topology,while slightly being inferior to that of the H5 topology.