Optimal Group Charging Method for Battery Integrated Modular Multilevel Converter

This paper proposes an optimal group charging method for battery integrated modular multilevel power conversion system in EV. During single phase AC charging mode, different amounts of sub-modules could be switched on due to its modular structure. With different number of sub-module inserted, the circulating current is also affected, which indicates the potential to decrease system losses. The mathematical analysis between inserted number and power losses is presented. With the optimal inserted number selected, the efficiency of power conversion system could be improved. Finally, simulation results are also obtained to verify the effectiveness of optimal group charging method.