Flux and Loss Map Based Evaluation of the Efficiency Map of Synchronous Machines

This article presents a methodology for the efficiency maps evaluation of synchronous electric machines. The procedure is based on the manipulation of flux linkage, iron and PM loss maps obtained via 2D magneto-static Finite-Element Analysis. The paper thoroughly describes the procedure and its key computational steps, all referring to open-source Matlab code available to the public. A method for iron loss evaluation from magneto-static FEA is proposed, valid for both sinusoidal and PWM supply. Experimental results are provided for the validation of single loss terms calculation and for the whole efficiency map, with reference to an interior permanent magnet machine designed for traction. FEA evaluation of PWM supply conditions relies on the off-line computation of the motor phase currents using a custom PLECS model of the drive, still flux-map based. This step of the procedure is also validated experimentally. The proposed methodology covers permanent magnet synchronous and synchronous reluctance machines, and finds prominent application in the automotive field, for traction and on-board generation.