Control Strategy of Electric Propulsion System to Improve Ship Dynamics

In this paper, a strategy for controlling a powertrain of the electric propulsion ships is proposed. The proposed control strategy enables rapid acceleration and deceleration of the vessel by actively limiting output torque reflecting limitations of the components in the powertrain. The propulsion motor's output power and its rate are both controlled to satisfy the limits of each component, including gear and propeller. The effectiveness of the proposed method has been verified based on the extensive computer simulations of the powertrain of a target ship and a small-scaled experiment. As a result of a simulation, an acceleration time of a 2300-ton class electric propulsion ship has been reduced from 308 seconds to 142 seconds.