This article proposes a robust dual-vector model predictive control (RDVMPC) strategy for high-power three-level inverters, specifically designed to optimize current harmonics. By extending the concept of total harmonic distortion (THD) to the entire time domain, the current deviation is redefined, and a novel cost function is formulated. The proposed strategy incorporates dual-vector control to maintain a fixed switching frequency while optimizing the sequences and duty cycles of the vectors to further mitigate THD. A novel ultra-local model is employed to eliminate dependency on precise system parameters, with unknown components accurately estimated through an extended state observer (ESO) equipped with an adaptive bandwidth gain mechanism. This mechanism dynamically adjusts to enhance disturbance rejection under parameter variations and suppress noise under steady-state conditions. The efficacy of the proposed method is substantiated through simulations and experimental validation on a 10 kW T-type inverter, demonstrating significant improvements in harmonic reduction and overall system performance.