Effect of Slot Leakage Flux on Winding Inductance and AC Resistance in an Axial Flux Machine with Distributed Windings

This paper investigates the magnetic flux leakage across the slots of the distributed windings in a yokeless, dual-rotor axial flux machine. The unique feature of the axial flux design presented is that distributed windings are used in a yokeless stator, where the conductors are in slots which are fully open at both ends and are thus subject to a greater effect of flux leakage across the slots. The slot leakage inductance is predicted with the analytical model and validated using a Finite Element (FE) model in this novel arrangement. An analytical model is developed to capture the skin and proximity effects of the conductors. Also, an analytical AC copper resistance model is developed, and the results are compared with those from FE analysis.