Design and analysis of dual wound machine for electric ships

Integrated full electric propulsion systems eliminate the direct mechanical coupling between the prime mover and the propeller, enabling easier connection of multiple prime movers and allowing more equitable and fuel-efficient engine loading. These features are important in both cruise ship and naval warship design. Propulsion and ship service systems require different electrical ratings. The general solution is to use multiple electrical machine sets. To approach the most compact design and maximise the weight reduction, a dual wound machine is considered in this paper. It has dual two-layer windings which share the same slots and uses one prime mover, to produce two independent power supplies. This paper designs a dual wound machine with no electromagnetic coupling due to the airgap fields, by algebraically analyzing the harmonic distribution. Further verification of the nil electro-magnetic coupling due to both the airgap and slot leakage fluxes is provided by 2D finite element modeling. Both loaded and unloaded conditions are considered.