This　paper　proposes　a　novel　high　voltage　gain　structure　of　DC-DC　converter　with　soft-switching　ability　for　photovoltaic　(PV)　applications.　A　small　size　coupled　inductor　with　one　magnet　core　is　utilized　to　improve　the　voltage　conversion　ratio　in　the　proposed　converter.　The　converter　has　one　active　MOSFET　with　low　conducting　resistance　(RDS-ON),　which　in　turn　reduces　the　conduction　losses　and　complexity　of　the　control　section.　Due　to　the　low　input　current　ripple,　the　lifetime　of　the　input　PV　panel　is　increased,　and　the　maximum　power　point　(MPP)　of　the　PV　panel　can　be　easily　tracked.　The　MOSFET＇s　zero-voltage　and　zero-current　switching　and　diodes　are　the　other　countenance　of　the　proposed　converter,　which　improve　its　efficiency.　Additionally,　an　improved　Perturb　and　Observe　MPP　tracking　(IP&O　MPPT)　algorithm　is　introduced　to　boost　the　extracted　power　of　the　input　PV　sources.　To　validate　the　performance　of　this　converter,　the　operation　modes　principle,　steady-state　and　efficiency　survey,　and　comparison　results　with　other　same　family　converters　are　carried　out.　Finally,　an　experiential　prototype　is　built　with　20　V　input,　200　V　output,　power　rate　of　200　W,　and　50　kHz　operating　frequency　to　validate　the　mathematical　analysis　and　effectiveness　of　the　proposed　structure.　The　efficiency　of　the　proposed　converter　was　estimated　by　over　95%　at　various　power　levels.　©　2013　IEEE.