Power Smoothing in MCT System with Supercapacitor Based Energy Storage for Islanded Grid

This paper investigates modeling, control and power management aspects of tidal energy conversion system (TECS) with an energy storage system (ESS) unit connected to an islanded grid. The model presented in this work takes into account entire conversion system including machine, AC-DC converter, DC-AC converter, DC-DC converter and supercapacitor-based energy storage system. A dynamical modeling of the complete TECS is achieved using the graphical formalism Energetic Macroscopic Representation (EMR) and inversion-based rules are used for the control development. In addition to the modeling and control of TECS, a simple algorithm to manage the power flows between the system components is proposed. The proposed algorithm ensures the slope limitation of the active power supplied to the grid and maintains the state of charge of the supercapacitor at acceptable levels. The performances of the overall grid-connected TECS with ESS are evaluated based on tidal current data from the Ushant Island.