In order to reduce the leakage current to meet the standard
in [14], conventional half bridge inverter or full-bridge inverter
with bipolar modulation technique are used in transformerless
PV systems to generate constant CMV to reduce the leakage
current. However, a 700-V dc-link voltage is required for the
half bridge and diode-clamped topologies [15]–[17]. For fullbridge
bipolar modulation, high losses and reduced efficiency
are observed due to two-level bipolar output voltage. As a result,
the voltage stress across the inductors is doubled and current
ripples increase. Larger filter inductors are required, increasing
the cost and size of the PV systems