A Bidirectional Multiple-Input Multiple-Output Modular Multilevel DC–DC Converter and its Control Design

This paper introduces a multiple-input multiple-output modular multilevel dc-dc converter (MIMO-MMC) and its associated control scheme. The proposed topology has a bidirectional structure and may be utilized in both low- and high-power applications ranging from approximately 100 W-10 MW. The modular structure of the MIMO-MMC enables efficient component utilization through module voltage and current sharing capabilities. The topology can supply or extract regulated power from an arbitrary number of controllable voltage nodes without requiring source or load multiplexing, resulting in minimized filtering requirements. The MIMO-MMC's structure is described, and the steady-state operation of the converter is theoretically analyzed. The dynamic models of the converter for both step-down and step-up configuration are derived and employed to devise an effective control algorithm for closed-loop operation. A general method is provided for stability analysis of the proposed closed-loop system followed by a case study verifying stability of the system at different operating points. The steady-state operation and dynamic response of the converter under both configurations is investigated through simulation and experiment.