Thermal Parameters Evaluation for Stator Fractional-Slot Concentrated Winding Machines

The aim of this paper is the determination of the thermal parameters and thermal coefficients for a fractional-slot concentrated winding machine. In previous papers, the authors presented a detailed analysis of the values obtained for machines equipped with distributed windings. Since the two winding topologies have a complete different realization, it has been mandatory to validate the approach proposed for distributed windings even in the case of concentrated windings. In this sense, the experimental tests and the model validation have been performed using a reduced-scale prototype of a generator properly designed for aircraft applications. The machine is equipped with single-layer fractional-slot concentrated windings and the coils are produced using Litz wire. The obtained results indicate that the proposed method to estimate the thermal parameters and coefficients for distributed winding machines can be used for this specific fractional-slot concentrated winding machine as well.