A novel compensation strategy of actual commutations for ground leakage current reduction in PV transformerless converters

The design of a PV grid-connected converter usually comprehends a galvanic isolation between the grid and the photovoltaic panels. Recently, for low power applications, the galvanic isolation has been removed with the aim to increase efficiency and reduce the cost of the converter. Due to the presence of a parasitic capacitance between the photovoltaic cells and the metal frame of the PV panel, usually connected to earth, a high value of common mode current (i.e. ground leakage current) can arise. In order to limit the ground leakage current (which deteriorates the power quality and generates EMI), new converter topologies have been proposed. This paper deals with a particular topology that, working in conjunction with a compensation strategy of power switches actual commutations, can guarantee low ground leakage current regardless the parameters tolerance of the power circuit. Simulation and experimental results confirm the effectiveness of the proposed solution.