A series-connected DC microgrid cluster with differential power processing characteristics

A series-connected DC microgrid cluster with differential power processing characteristics is proposed in this paper. In a cluster with n microgrids, a total of n bidirectional DC/DC converters are employed to transfer power among microgrids, and one converter is used to balance the unbalanced current caused by the difference of the voltage among microgrids. Thanks to the proposed series scheme, the converters realize partial power conversion, which is beneficial to improve power density and reduce cost. Furthermore, for each converter, low voltage stress is achieved and more topology choices are available. In this paper, unified performance metrics of the new scheme are analyzed and compared with those of conventional scheme in detail. Subsequently, design consideration and control strategy are performed based on a case study for a cluster composed of three microgrids. Finally, experimental simulation of the theoretical analysis is also conducted.