SINGLE-PHASE H6 TRANSFORMERLESS INVERTER WITH A SIMPLE BOOST CONVERTER FOR PV-GRID TIED POWER SYSTEMS

Aparna Das, Sheeja G

Abstract: Inverters with transformers of conventional type, connected in PV grid-tied generation systems have now being replaced by transformerless inverters due to various reasons such as reduction in size, weight and cost, improvement in efficiency etc. Transformerless inverters cause a number of technical challenges in grid-connected PV systems, among which flow of leakage currents is a major problem. This leakage currents that flows between the parasitic capacitance of PV array and the grid has to be eliminated, which otherwise leads to serious safety problems. This paper deals with an H6 transformerless full- bridge inverter topology with low leakage currents that can be used in PV grid – tied applications. The operation modes for the proposed topology are discussed in this paper. A closed loop has been developed for maintaining the voltage constant at the grid side irrespective of changes in the input voltage. Aforementioned transformerless topology is simulated that validates the effectiveness of the converter.

Keywords: Common-mode voltage, grid-connected inverter, leakage current, photovoltaic (PV), transformerless inverter

DOI: https://doi.org/10.15623/ijret.2015.0406054