The　four-level　nested　neutral　point　clamped　(4L-NNPC)　inverter　has　recently　become　a　promising　solution　for　renewable　energy　generation,　e.g.,　wind　and　photovoltaic　power.　The　NNPC　inverter　can　stabilize　the　flying　capacitor　(FC)　voltages　of　each　bridge　through　redundant　switch　states　(RSSs).　This　paper　presents　an　improved　three-layer　sequential　model　predictive　control　(3LS-MPC)　method　for　4L-NNPCs.　This　method　eliminates　weighting　factors　and　removes　the　switch　states　that　generate　high　common-mode　voltage　(CMV).　Before　selecting　the　optimal　vector,　we　disable　certain　switch　states　which　affect　the　FC　voltages,　continuing　to　deviate　from　the　desired　value.　Then,　adopting　a　two-stage　optimal　vector　selection　method,　we　select　the　optimal　sector　based　on　six　specific　vectors　and　choose　the　optimal　vector　from　the　seven　vectors　in　the　optimal　sector.　The　feasibility　of　this　method　was　verified　in　Matlab/Simulink　and　the　prototype.　The　experimental　results　show　that　compared　with　classical　FCS-MPC,　the　proposed　3LS-MPC　method　reduces　the　common-mode　voltage　and　has　better　harmonic　quality　and　more　stable　FCs　voltages.　©　2025　by　the　authors.