Dynamic Modeling and Stability Analysis of Onboard DC Power System for Hybrid Electric Ships

This paper presents the dynamic modeling and stability analysis of the onboard DC power system, applicable to hybrid electric ships. The system topology is established with a special focus on the integration of the energy carriers with power electronic converters. The modeling of the AC/DC rectifier, DC/DC converter, filters and energy storage systems (ESS), such as battery and supercapacitor, is investigated. AC/DC rectifier is modeled with decoupling control through an LCL filter, and the DC/DC converter modeling is compared with the state-space averaging method and generalized averaging method. The performance of the integrated model is presented both in charging mode and in discharging mode of the energy storage system and the results show the effectiveness of the controllers and the power regulation of the ESSs. In the end, the limitation of the load is obtained by the stability analysis.