Magnetic Decoupling of Winding Design in Dual Wound Generators

A general shipboard power system contains multiple electrical machine sets to provide electrical power with different ratings for both the propulsion system and the ship service. In order to achieve the most compact design and maximize the weight reduction, a study of using a single dual wound generator to replace the electrical machine sets is presented in this paper. It consists of dual two-layer windings of different pole numbers which use the same slots and share one prime mover, producing two independent power supplies. This paper verifies a dual wound machine designed for no electromagnetic coupling by algebraically analyzing the spatial harmonic magnetic field distribution. Further verification of the absence of electromagnetic coupling due to both the airgap and slot leakage fluxes is provided by 2D finite element modeling. The dual wound generator prototype using the principle is designed, built and experimentally tested. The experimental results match well with the simulation results, validating the independence of the two power outputs and showing that the winding end-turns also do not couple. The results are significant for applications where multiple independent power supplies are needed, or where an auxiliary power supply is needed which could be drawn from an existing traction motor.