Interaction analysis and integrated control of hybrid energy storage and generator control system for electric ship propulsion

Ship propulsion systems experience large power and torque fluctuations on their drive shaft due to hydrodynamic interactions and wave excitation. For electric propulsions, a hybrid energy storage system (HESS) could be an effective solution to address the negative impact of these fluctuations. However, the HESS, when introduced into the existing shipboard electrical propulsion system, will interact with the power generation control systems. In this paper, a model-based analysis is performed to evaluate the interactions of the multiple power sources when a hybrid energy storage system is incorporated. The study has revealed undesirable interactions when the controls are not coordinated properly, and leads to the conclusion that a system-level energy management strategy (EMS) will be needed. To evaluate the benefits of the system-level EMS, a comparative study is performed, and results show that the system-level EMS has advantages over other strategies in terms of many of the performance metrics.