OPTIMIZATION OF MICRO-GRID USED IN MARINE PROPULSION SYSTEMS

Abstract

Highest percentage of the world trade is through marine transport and it is expanding continuously because of economic liberalization. This has increased the throng of marine vehicles and tugboat operation at ports. Tugboats are also called workhorses and are usually used for carrying goods, maneuvering big ships in and out of harbor, for marine patrol and several other harbor functions. As all marine vehicles like cruisers, cargo ships, oil containers, combatant ships and tugboats are clustered in the harbor causing increased levels of air, water, & land pollution. Therefore, International Maritime Organization has imposed strict emission norms in marine sectors for reducing pollution. An extensive research is necessary for control of these pollution for sustainable development. In this dissertation some efforts were made to increase the fuel efficiency, consequently decreasing fuel wastage and pollution from it. In this dissertation the most realistic model of a tugboat is considered and an optimal fuel saving strategy is developed by considering the concepts of micro grid and hybrid electrical vehicles. In this strategy variable speed technology is proposed instead of conventional fixed speed technology and an energy management system is designed for optimal operation of the tugboat. The adopted optimization techniques shares the power among multiple energy sources available in tugboat. In addition to this a novel prediction scheme predicts the future load profile based on mathematical approach. Using the proposed optimization problem formulation 2.6 % of fuel saving per cycle is observed. Doubly fed induction machine is used for variable speed operation in the propulsion system which increases reliability and also this strategy is designed for energy management system at the propulsion motor drive of the tugboat, which further increases efficiency of nearly 1.83 % per cycle.