With　the　rapid　development　of　new　energy　vehicles,　the　bidirectional　charging　technology　of　vehicle　chargers　is　becoming　more　and　more　important,　LLC　is　difficult　to　achieve　a　wide　range　of　gain　output.　In　addition,　the　reverse　gain　characteristics　of　LLC　are　poor.　Generally,　a　wide　frequency　range　is　used　in　LLC　resonant　converters　to　achieve　a　wide　range　of　voltage　output,　which　reduces　the　efficiency　of　LLC.　In　this　paper,　the　structure　of　three-phase　staggered　CLLC　resonant　converter　is　adopted,　and　the　wide　range　of　voltage　output　is　realized　by　adjusting　the　duty　cycle　at　a　fixed　frequency.　The　output　range　of　200-400V　is　achieved　by　BUCK　circuit　with　fixed　frequency　below　400V,　and　the　output　range　of　400-800V　is　achieved　by　BOOST　circuit　with　fixed　frequency　above　400V.　In　this　paper,　an　experiment　with　the　output　voltage　in　the　range　of　240　~　800v　is　set　up　by　simulation,　and　the　feasibility　and　effectiveness　of　the　scheme　are　verified.　©2023　IEEE.