Validation of an inverter topology for transformerless grid-connected photovoltaic system

Abstract

Solar photovoltaic (PV) systems are getting more and more widespread due to the recent price reduction in modules and technological developments of power electronics devices to be used in designing power conditioning unit. Generally, a strong affinity in grid-connected PV inverter topology is to use transformer in the grid interface. However, due to transformer, systems become bulky and involve additional losses. The elimination of the transformer abolishes galvanic isolation between the PV system and the utility grid, thus treating from the danger of direct current (dc) injection into the grid. Therefore, the choice of a proper topology for transformerless grid-connected application is crucial to avoid undesirable operational effects. This paper provides a detailed performance study of an IGBT-based modified full-bridge inverter topology from the aspect of single-phase transformerless grid-connected PV system application. Detailed simulation results under different environmental conditions are presented to validate suitability in the transformerless grid-connected application.