Design of Finite Control Set Model Predictive Controller for Modular Multilevel Converters with Common Mode Voltage Elimination

The Modular Multilevel Converter (MMC) has emerged as a key enabler for Medium Voltage Direct Current (MVDC) systems for larger vessels due to its redundancy, cost-effectiveness, and high performance. However, its complex control requires advanced strategies like Model Predictive Control (MPC). This paper applies Finite Control Set Model Predictive Control (FCS-MPC) to regulate MMC parameters including input DC current, output AC current, circulating current, sub-module (SM) capacitor voltages, and Common Mode Voltage (CMV). A three-phase MMC model, including CMV effects, is utilized for improved accuracy and output quality compared to single-phase models. CMV elimination is incorporated into the cost function. The FCS-MPC approach evaluates a finite set of switching possibilities, applies a cost function to determine the optimal choice, and implements the best configuration. Simulations performed in MATLAB/Simulink demonstrate that the proposed system effectively tracks the desired output current with low Total Harmonic Distortion (THD) while significantly reducing CMV. The results highlight the potential of FCS-MPC in enhancing power quality and reliability in shipboard MVDC systems.