Multi-objective Optimization Design of Modular Multilevel Multi-port DC-DC Converter Assessing Efficiency, Volume and Reliability

In this paper, a modular multilevel multi-port DC-DC converter (M3DC) consist of modular multilevel converter (MMC) and dual active bridges (DAB) is investigated, which is suitable for the DC distribution network integrated energy storage elements (ESE) in the next generation of vessel integrated power system (IPS). M3DC features flexible power control and excellent capability of fault-tolerant operation. To optimize the parameter design of the converter, a multi-objective optimization (MOO) scheme adopting non-dominated sorting genetic algorithm II, assessing efficiency, volume and reliability, is developed. The relationship between the parameters and the indexes is studied, and the constraints are presented. At last, the optimization scheme is implemented on a case study to illustrate the correctness and effectiveness.