Assessment of topologies to minimize leakage currents in transformerless PV inverters

Nowadays, the world is facing two challenges: the need for cleaner environment and the incessant increase in power demands. A situation that makes renewable energy sources, and particularly solar photovoltaics, more and more viable. Solar photovoltaic systems can be connected to the grid either with transformers or without transformers. In fact, the transformerless systems have been investigated and found to offer higher efficiency, smaller size and weight as well as more reduced cost. However, when no transformer is used, a common-mode voltage would appear and lead to leakage currents between the PV-array and the ground. This is why the main focus of recent researches is on minimizing or totally avoiding these leakage currents without causing any impact on the whole system efficiency. Accordingly, this paper deals with a comparison of promising solutions to achieve such a crucial goal.