Circulating Current Control for the Modular Multilevel Matrix Converter Based on Model Predictive Control

In this work, a continuous-control-set model predictive control (CCS-MPC) strategy, with a saturation scheme for protection, is presented for regulating the circulating currents of a modular multilevel matrix converter (M3C). The proposed approach is based on a state-space model of the M3C and allows protection and better utilization of the devices through a saturation scheme, which directly limits the arm currents and cluster output voltages by integrating the corresponding bounds as constraints of the CCS-MPC formulation. In order to solve the inherent optimization problem associated with the CCS-MPC, an active-set algorithm is implemented. Experimental and simulation results from a 27-cell M3C prototype validate the proposed strategy and illustrate the good performance achieved with the methodology presented in this work.