Voltage balancing strategy discussion on modular multilevel DC/DC converter

For power electronic transformer (PET) application, a modular multilevel dc-dc converter has been proposed. Only one high frequency transformer is used for voltage matching and power delivery, which substantially simplifies the circuit and the galvanic insulation issue. To guarantee viable operation of the converter, the voltage of each submodule must be balanced. In this paper, three voltage balancing strategies are discussed. The experimental results from a down-scaled prototype comply with the theoretical analysis very well.