It　is　considerable　to　reduce　the　computation　load　while　keeping　a　good　THD　performance　for　the　modular　multilevel　converter　(MMC)　with　model　predictive　control　(MPC).　In　this　paper,　the　discrete-time　mathematical　model　of　MMC　is　derived　and　the　output　voltage　ripples　of　the　cascaded　submodules　(SMs)　are　analyzed　in　detail.　Accordingly,　a　modified　increased-levels　MPC　method　A　(IL-MPC-A)　is　proposed　with　2N+1　ac-side　output　voltage　levels.　The　computation　load　is　significantly　reduced　without　losing　the　harmonic　circulating　current　suppression　and　capacitor　voltage　ripples　compensation　capabilities.　In　this　method,　the　cost　function　minimization　step　and　capacitor　voltage　sorting　algorithm　are　combined　to　determine　the　optimal　control　option.　In　addition,　to　avoid　the　selection　of　weighting　factors　and　further　reduce　the　computation　load　as　the　increasing　of　the　SM　number,　another　modified　IL-MPC-B　is　proposed　by　directly　calculating　the　optimal　ac-side　output　voltage　level　and　arm　summation　voltage　according　to　the　discrete-time　mathematical　model.　As　a　result,　the　ac-side　output　current　and　circulating　current　controls　are　decoupled.　Furthermore,　the　capacitor　voltages　are　balanced　with　a　proposed　control　scheme　by　adjusting　the　circulating　current　reference.　The　effectiveness　of　the　proposed　MPC　methods　are　verified　by　simulation　and　experimental　results.　IEEE