An Improved Reference Generator Based on MPC of Circulating Currents and Common-Mode Voltage for Modular Multilevel Matrix Converters

This article proposes an improved reference generator based on model-predictive-control (MPC) for the modular multilevel matrix converter (M3C). The novelty of the proposal is in optimally obtaining the circulating currents and CMV references to achieve the intercluster balancing (ICB) control and low-frequency oscillations mitigation (LFOM) of the M3C. Additionally, the proposed optimal control problem is designed in the original framework and includes bound constraints for circulating currents and CMV for a proper operation of the M3C. As a result, the MPC-based reference generator allows to regulate the cluster energies with low capacitor voltage ripple and operate at low and equal frequencies while keeping the cluster currents under safe limits. Experimental results have been conducted using a 3 kVA prototype to validate the proposed strategy's effectiveness and high-quality performance.