针对现有固态变压器拓扑结构存在的局限性及控制方法的不足, 本文提出了一种模块化多电平型固态变压器, 并相应介绍了一种内模控制实现方法.-To overcome the limitation of the existing topologies and control strategies of Solid State Transformers, a Modular Multilevel Converter type Solid State Transformer(MMC-SST) topol