Electrification Solution with Supercapacitor Storage of a Bow Thruster for River Tugboat

Bow thrusters usually are hydraulic and mechanically driven engines, used for the positioning maneuvers of River and sea boats. The peculiarity of these systems operating on short time intervals is their low rate of use (approximately 2%) but requiring maximal power. The main purpose of the work is to propose an innovative electrical hybridization of the bow thruster for a river tugboat. This electrification solution enables the bow thruster to operate with no-emissions, reduced noise and is a subsystem of green ship. Main challenge is to manage high torque and low speed requirements of the bow thruster system during the positioning maneuvers, by adding a dynamic electrical storage system, based on high capacitance value Supercapacitors, and in association with the electrified propeller motor. The knowledge concerns hybrid electrification, involving new-technology elements, energy storage based on supercapacitors, the high amplitude low speed torque control strategy. With fully reversible electrical motorization, the propeller is able to operate for both direct-reverse ways of rotation. Proposed electrical solution would hence provide large expected benefits in terms of energy efficiency, compactness, weights, costs, and contribute to a more eco-friendly ship. Numerical simulation and first results on laboratory test bench validate the proposed electrification concept.