A　non-isolated　soft-switching　high-voltage-gain　quasi-Z-source　DC-DC　converter　is　proposed　in　this　paper.　The　converter　has　the　advantages　of　a　continuous　input　current,　a　common　ground　for　input　and　output,　a　high　voltage　gain,　and　low　stresses　of　switching　devices.　At　the　same　time,　all　the　switches　in　the　converter　operate　under　zero　voltage　switching　(ZVS)　conditions,　and　all　the　diodes　operate　under　zero　voltage　zero　current　switching　(ZVZCS)　conditions,　which　can　reduce　the　switching　losses　of　the　switches　and　the　reverse　recovery　losses　of　the　diodes.　By　introducing　a　three-winding　coupled-inductor,　the　voltage　gain　of　the　converter　is　improved,　while　the　addition　of　an　active　clamp　circuit　reduces　the　voltage　spikes　at　both　ends　of　the　switches.　The　coupled-inductor　with　a　smaller　inductance　value　corresponds　to　a　smaller　copper　loss　and　volume,　thereby　improving　the　efficiency　and　power　density　of　the　converter.　A　thorough　analysis　of　the　working　modes　of　the　converter　is　conducted,　and　the　voltage　gain　of　the　converter,　as　well　as　the　voltage　and　current　stresses　of　the　components,　is　derived.　Steady-state　analysis　and　parameter　design　are　carried　out.　Finally,　a　100　kHz,　200　W,　38~380　V　experimental　prototype　is　built,　and　the　efficiency　of　the　converter　at　rated　power　is　96.13%.　The　experimental　results　are　consistent　with　the　theoretical　analysis,　indicating　the　feasibility　of　the　proposed　converter.　©2024　Chin.Soc.for　Elec.Eng.