A Multi-Layer Sequential Model Predictive Control of Three-Phase Two-Leg Seven-Level T-Type Nested Neutral Point Clamped Converter Without Weighting Factors

In this paper, a triple-layer sequential model predictive control (SMPC) approach without weighting factors is proposed for a three-phase two-leg 7-level T-type nested neutral point clamped (T-NNPC) converter. The main objectives of this paper are to eliminate the selection of weighting factors and enhance the reliability of system in the control process. In the proposed design, three cost functions are formulated in a cascaded way to avoid the weighting factors tuning while not compromising the computational complexity. Furthermore, the three-phase two-leg 7-level T-NNPC converter is investigated to improve the fault-tolerance ability in case of a faulty leg condition. Finally, the effectiveness of the control methodology for the three-phase two-leg 7-level T-NNPC converter is validated by comparative simulation studies.