Ultra-Capacitor Models for All Electric and Hybrid Ship Power Systems

In this paper a deep investigation of supercapacitor device modeling is performed with specific reference to hybrid energy storage modules, suitable to support both all electric /hybrid propulsion and on board MVDC distribution marine systems. In those applications, the combination of batteries and supercapacitors in realizing energy storage hybrid devices overtakes the intrinsic disadvantages of single use of electrochemical batteries and supercapacitors. On the other hand, proper design and management strategies of hybrid architecture are required in order to achieve the best performance in terms of dynamic and life cycle assessment on load profile of marine applications. In this way, the main results presented in this paper consists in a simple quadratic mathematical model of supercapacitor, evaluated as a quadratic function of the ultra-capacitor voltage, which is validated experimentally on the base of operative-cycle-based loading profiles, representative of marine application. The results and comparison reported in this work confirm the validity of the proposed model for preliminary design of hybrid energy storage systems and management strategies evaluation on the electrification of ship power systems.