Three-phase　LCL-Filter　NPC-Type　grid-connected　inverter　has　been　widely　used　in　the　renewable　energy　generation　systems　with　the　advantages　of　high　efficiency,　high　power　and　low　cost.Finite　control　set　model　predictive　control　(FCS-MPC)　has　strong　robustness　and　fast　dynamic　response,　so　it　is　widely　used　in　grid-connected　inverter　control.　However,the　traditional　FCS-MPC　bears　with　irregular　switching　state,which　will　reduce　the　current　tracking　accuracy,　produce　current　ripple　and　electromagnetic　noise.Aiming　at　the　above　shortcomings,　an　efficient　and　fixed　operation　frequency　model　predictive　without　weighting　factor　is　presented　to　ensure　fixed　operation　switching　frequency.The　voltage　vector　of　different　voltage　vectors　is　selected　according　to　the　location　of　the　voltage　vector　reference,　and　the　switching　time　of　the　selected　are　directly　calculated　by　the　inversely　proportional　with　cost　function　value　of　the　vectors.　To　verify　the　correctness　and　effectiveness　of　the　proposed　control　strategy,　a　complete　simulation　model　and　experimental　prototype　platform　under　the　digital　control　is　established.　The　simulation　and　experimental　results　show　that　the　steady　and　the　transient　performance　of　the　grid　current　with　the　proposed　control　strategy　are　effectively　improved.　©　2021　IEEE.