Finite Control Set Model Predictive Control for Five-Level Modified Active Nested Neutral Point Clamped Converter

The classical nested neutral-point-clamped (NNPC) and nested T-type converters experience large voltage fluctuations across the flying capacitors (FCs). To deal with the issue, this paper proposes a new five-level modified active NNPC (5L-MANNPC) converter that is free from dc-link capacitors. The key feature of such configuration is that it eliminates the need for additional control loop for dc-link voltage balancing. The mathematical model of the converter is developed, and a finite control set model predictive control (FCS-MPC) approach is designed to achieve accurate tracking of the output current and voltage balance across the FCs for the proposed converter. Lower FC voltage ripples and less optimization targets are the main merits of the proposed topology. The experimental results are provided to validate the feasibility of the proposed converter.