  The mismatching phenomenon is one of the main issues in photovoltaic (PV)
applications. It could reduce the generated power of a string when a PV panel
has different performances from the other PV panels connected to the same
string. Distributed Maximum Power Point Tracking (DMPPT) architectures are one
of the most promising solutions to overcome the drawbacks associated with
mismatching phenomena in PV applications. In this kind of architectures, a
DC-DC module integrated converter (MIC) manages each PV panel, isolating it
from the rest of the PV panels, for harvesting the maximum available power from
the Sun. Due to the high number of DCDC converters used in a grid-tied PV
installation, the most desired MIC requirements are high efficiency, low cost
and the capability of voltage step-up and step-down. This paper proposes the
Buck-Boost Modified Forward (BBMSF) converter as a good candidate to be applied
in DMPPT architectures. A complete analysis of the BBMSF converter is carried
out, including the steady-state analysis as well as the small signal analysis
in continuous conduction mode. The main advantages of the BBMSF converter are
its step-up and step-down voltage transfer function; a higher simplicity, since
it only includes a single controlled switch; the soft switching characteristics
in all the diodes and MOSFET, reaching in some cases ZVS and ZCS, and yielding
high efficiencies; the use of an autotransformer, with better performances than
a typical Forward transformer; and the good dynamic performance, like the
Forward converter ones. The theoretical analyses are validated through the
experimental results in a 225 W BBMSF prototype designed and built under the
requirements of a 100 kW grid-tied PV installation, achieving an efficiency up
to 93.6%.
