Current source DC/AC converter for photovoltaic systems

Transformerless inverters are being widely used in low power grid-connected photovoltaic (PV) generation systems. Transformer elimination has many advantages; it reduces cost, size, weight and also increases the whole system efficiency. However, once the transformer is removed, there is no galvanic isolation between grid and PV array and, as a consequence, a leakage current may appears due to the photovoltaic panel parasitic capacitance to the ground, resulting in prohibitive electromagnetic interference and security issues. This paper presents a novel current source DC/AC topology in order to reduce this ground leakage current. It is established that the neutral line of the grid is the same as the negative terminal of the PV system, eliminating this way, any possibility of leakage current through this terminal.