Dynamic Performance of a Decoupled Dual Wound Synchronous Generator for Electric Propulsion of Ships

The dual wound generator brings significant advantages to integrated electric propulsion systems in ships, particularly in terms of footprint reduction and space saving. However, prior research on machines using the same pole number for each of the windings has highlighted the challenge of severe magnetic coupling effects between the two outputs when subjected to dynamically changing loads. This reduces the stability of the electric power distribution system and its controllability. This paper proposes a new design based on a wound synchronous generator that overcomes this limitation by using different pole numbers for the windings to provide independent power supplies for both ship propulsion and ship services. In this novel approach, the two sets of windings physically share the same slots within a single machine frame but are fully electromagnetically decoupled. To investigate and validate this electromagnetic decoupling, the impact of load conditions such as resistive, resistive-inductive, and rectified DC loads are modelled and experimentally evaluated in detail. The results demonstrate that the novel dual wound generator operates as a fully decoupled machine, where the load change in one winding output does not impact the other winding, regardless of the load type. This unique ability to decouple the two outputs represents a significant innovation in the development of electric propulsion systems for transportation applications. This work therefore demonstrates the significant potential of the use of dual wound generators for applications in electric ships, electric aircraft, and heavy-duty vehicles, where independent power supplies are essential for efficient and reliable operation.