Accurate Analytical Eddy Current Loss Calculation in Hairpin Windings

This paper explores the use of the Sub-Domain Method (SDM) for calculating power loss from eddy currents in hairpin windings. The model uses polar coordinates and discrete boundary conditions to suit the rectangular geometry of hairpin stators. It accurately computes the current density distribution from skin and proximity effects due to the armature reaction field, proving to be a valuable tool in optimization routines. The proposed model is capable of handling different conductor sizes, layer numbers, and single-phase and dual-phase slot arrangements, found in full-pitch and short-pitch winding configurations, respectively. Single-slot comparisons with Finite Element Method (FEM) simulations show that the tool delivers comprehensive, flexible, and accurate results; the difference for the total power loss between the analytical model and FEM at 1500 Hz stays under 1.03% relative error.