Magnetic Field Solution in Doubly Slotted Airgap of Conventional and Alternate Field-Excited Switched-Flux Topologies

A general solution of the magnetic field in the airgap of conventional and alternate field-excited switched-flux (FE-SF) machines is proposed in this paper. The analytical model is based on the subdomain method. It involves the solution of governing field equations in a doubly slotted airgap using the variable separation method. The complete model is derived and described in a general manner so that it can be easily extended to unconventional FE-SF topologies. By means of example, analytical predictions of airgap field are extensively compared and validated using 2D FE results. FE simulations were performed on a 24-10 classical FE-SF structure and also on a novel 18-11 FE-SF machine with additional spacer teeth.