Optimization of MVDC Power System of All Electric Ship Based on Hybrid Energy Storage

In this paper, a hybrid energy storage system consisting of supercapacitor and battery is proposed in the medium voltage DC electric propulsion system. The energy storage module is used to stabilize the power fluctuation of the ship network and improve the system stability and power quality. The working principle of supercapacitor and battery is studied and the model structure of the hybrid energy storage system suitable for medium voltage DC ship power grid is determined. At the same time, the energy complementary characteristics of energy storage components are considered, combined with fuzzy PI charge and discharge control strategy to realize hybrid energy storage with accurate and efficient energy management of the system. For energy transfer among the energy storages and the MVDC system, bidirectional dc-dc converters with dual active bridge configuration are used. Finally, through simulation analysis, the influence of the hybrid energy storage system on the back-end weakening fluctuation is studied, and the effect is better than a single energy storage method. The DC bus voltage stability is improved, and the system performance index is optimized.