The design and construction of a 500VA microinverter for photovoltaic
applications is presented. The developed microinverter is capable of
operating as a standalone AC voltage source for small loads or,
alternatively, as a grid-parallel system. Possible applications are
therefore small off-grid installations as well as installations where
space constraints do not allow enough modules to be combined to use
string inverters. The design of the microinverter is based on a two
stage concept. Two alternative topologies for the DC-DC converter stage
have been considered. A prototype using a current-fed push-pull
converter and a full-bridge output stage has been built and was shown to
be operational. The prototype has achieved a maximum overall efficiency
of 93.9 %, which includes all sensing, control and driving losses. SiC
MOSFETs have been utilized to illustrate the capability of wide-band-gap
devices