Sizing and simulation of an inverter-fed permanent-magnet linear synchronous drive for servo-assistance of a ship steering gear

Hydraulic drives used on board ship to empower rudders, stabilizing fins, anchor winches, etc., are often characterized by low efficiencies, heavy maintenance, frequent oil leaks and large weight and size. To overcome these drawbacks, oil-free inverter-fed alternative drives can be conceived. In this paper a concept design of a full-scale permanent magnet linear synchronous motor directly coupled to a twin rudder on board ship is presented, used as a servo-motor. The servo-assistance capabilities are simulated and evaluated by using a complete model of the electro-mechanic-hydraulic system in Simulink environment. The results show the effectiveness of the electromagnetic drive servo-assistance. This research has been carried out in the framework of the Italian Defence Research National Program for the development of `dual use' technologies.