Impact of Soft Magnetic Material on Construction of Radial Flux Electrical Machines

Electrical machines with distributed concentrated windings are challenging the selection of the soft magnetic materials due to stator design and power conversion efficiency. A shorter magnetization path and relatively high magnetization frequency is beneficial for low-permeability soft magnetic materials with low power losses in the core. In this paper, a three-phase machine with laminated and iron powder cores is analyzed with focus on a modular winding design, the torque capability, and the stator energy conversion efficiency. Different iron powder cores are compared to a laminated core using 2-D finite element analysis (FEA). The three-phase machine torque is compared among a conventional distributed concentrated winding, an axially distributed wave-winding, and a number of circumferentially distributed wave-winding segments. According to 3-D FEA, the conventional coils are preferred if the permeability of the core is low.