The　power　system　is　an　important　part　of　the　spacecraft.　The　Superbuck　converter　is　a　high-order　topology　with　continuous　current　and　high　efficiency.　However,　when　the　main　circuit　parameters　are　improperly　selected,　the　right　halfplane　(RHP)　zero-point　exists　in　the　small-signal　model　of　the　converter,　which　increases　the　difficulty　of　the　control　system　design.　In　this　paper,　methods　such　as　increasing　the　damping　loop　and　optimizing　the　control　loop　are　used　to　improve　the　stability　of　the　converter.　The　main　circuit　parameters　were　analyzed　and　calculated.　The　PSIM　software　was　used　to　analyze　the　time　domain　transient,　frequency　domain　characteristics,　ripple　and　parameter　scanning　of　the　circuit　model　with　parasitic　parameters.　The　voltage　control　method　was　selected　and　the　modules　of　the　control　loop　were　designed.　The　Bode　plot　shows　that　the　system　is　robust　enough　and　stable.　In　addition,　using　the　CST　software　to　simulate　the　electromagnetic　field　distribution　of　the　devices.　The　simulation　results　can　lay　a　good　foundation　for　the　actual　production　in　the　next　step.　Due　to　its　unique　advantages,　Superbuck　circuit　will　have　broad　application　prospects　in　the　space　power　controller　unit(PCU).　©　2019　IEEE.