| Abstract |
Grid-connected photovoltaic (PV) systems
usually include a line transformer in their power conversion
stage. This transformer guarantees galvanic isolation
between the grid and the PV system, thus providing
personal protection and avoiding leakage currents between
the PV system and the ground. Furthermore, it also ensures
that no continuous current is injected into the grid.
However, because of its low frequency (50 Hz), the
transformer is big, heavy and expensive. As an alternative to
the grid-connected PV systems with line transformer, new
transformerless inverter topologies are being studied. If no
transformer is used, a galvanic connection between the grid
and the PV array exists. In these conditions, leakage
currents due to the capacitance between the photovoltaic
array and earth could occur and increase the
electromagnetic emissions. To avoid these leakage currents,
it is necessary to use inverter topologies that avoid commonmode
voltages. In this paper, a new transformerless singlephase
PV inverter with six IGBTs and one diode is
proposed. This topology generates no common-mode voltage
and has a higher efficiency than the existing topologies. The
topology has been validated by simulation. |
