This　paper　first　introduces　an　existing　circulating　current　controller　for　modular　multilevel　converter　(MMC)　through　redundant　voltage　levels　with　detailed　analysis　for　the　controlled　circulating　current.　To　further　reduce　the　peak-to-peak　value　of　the　circulating　current　at　switching　frequency　and　decrease　the　total　control　error,　a　fixed-band　redundant　state　transition　principle　is　put　forward　in　this　paper,　so　that　the　circulating　current　can　be　approximately　limited　within　the　fixed-band.　Compared　to　traditional　control　methods,　the　main　advantages　of　the　proposed　strategy　are　unaffected　arm　voltage　reference,　simple　implementation,　reduced　switching　frequency　and　very　fast　dynamic　performance.　Simulation　results　verified　the　effectiveness　of　the　proposed　control　strategy.