A New Concept of PTI/PTO for Marine Applications

This paper deals with the performances of High Torque Density induction machine driven by a PWM 6.6kV Transformerless Variable Speed Drive (Fig. 1) [1]. Shaft generators are commonly used to produce electrical power for the ship's network where a mechanical shaft is driven by a slow speed engine [2] [3] or through a common gear box [8]. For large PTO (Power Take Off) applications the use of variable speed drive allows to operate them over a wide range of engine speed as fixed pitch propeller only is used. The direct drive arrangement brings significant benefits in term of reliability and maintenance. PTI mode (Power Take In) brings operational flexibility to optimize energy consumption by regulating the available power from the WHRS (Waste Heat Recovery System).