The　deep-sea　aquaculture　industry　will　become　one　of　the　important　pillars　of　the　future　marine　economy.　However,　the　application　of　clean　energy　in　the　new　scenario　needs　to　be　strengthened　for　platform　operation.　For　this　kind　of　renewable-energy　distributed-generation　system,　an　energy　storage　system　is　essential.　A　bidirectional　DC–DC　converter　is　essential　for　distributed　power　generation　systems.　It　connects　a　variety　of　renewable　energy　sources　with　energy　storage　cells.　A　high-gain　bidirectional　Cuk　circuit　with　zero　ripple　is　proposed　in　the　paper.　It　is　characterized　by　a　simple　structure,　zero　ripple,　low　voltage　stress　of　semiconductor　power　devices,　and　high　voltage　gain.　A　passivity-based　control　with　linear　active　disturbance　rejection　is　proposed　to　solve　the　problems　of　the　large　steady-state　error.　The　zero　steady-state　error,　strong　robustness,　and　whole-range　stability　have　been　obtained　for　the　proposed　control　strategy.　Finally,　a　simulation　was　carried　out.　A　100　W,　48　V/400　V　prototype　was　built　to　verify　the　validity　of　the　theoretical　analysis　for　the　proposed　circuit.　The　improved　passivity-based　control　strategy　was　verified　to　solve　the　contradiction　between　rapidity　and　overshoot.　It　can　be　realized　to　improve　the　dynamic　performance　of　the　proposed　converter　and　achieve　robust　control.　©　2023　by　the　authors.