Modelling and simulation of hybrid electric ships with DC distribution systems

DC power system in ship applications is an emerging technology, which provides new opportunities for reducing fuel consumption and emission. However, the resulted power electronic-based system onboard the ship requires effective analysis tools to facilitate a full-realization of the advantages. This paper reviews the modelling of hybrid electric ship components including mechanical and electrical elements. Power electronic converters are modeled by nonlinear averaging methods to suit system-level studies. A unified model for bidirectional converters is proposed to avoid transitions between two separate models. A simulation platform using the derived models is developed for system-level analysis of hybrid electric ships. Simulation results of a hybrid electric ship with two diesel generators, a fuel cell, and an energy storage module are presented for different modes of operation.