{"references": ["", "J. Santiago, H. Bernhoff, B. Ekergard, S. Eriksson, S. Ferhatovic, R. Waters,\nM. Leijon, Electrical Motor Drivelines in Commercial All-Electric\nVehicles: A Review, IEEE Transactions on vehicular technology, vol. 61,\nno. 2, February 2012.", "M. M\u00a8argner, W. Hackmann, Control challenges of an externally excited\nsynchronous machine in an automotive traction drive application, Emobility\n- Electrical Power Train, November 2010.", "M. Niemel\u00a8a, Position sensorless electrically excited synchronous motor\ndrive for an industrial use based on direct flux linkage and torque control,\nPhD thesis, Lappeenranta University of Technology, Finnland, 1999.", "I. Boldea, G. Andreescu, C. Rossi, A. Pilati, D. Casadei Active Flux Based\nMotion-Sensorless Vector Control of DC-Excited Synchronous Machines,\nEnergy Conversion Congress and Exposition, September 2009.", "A. Girardin, G. Friedrich, Optimal control for a Wound Rotor Synchronous\nstarter generator, Industry Applications Conference, October\n2006.", "R. Grune, Verlustoptimaler Betrieb einer elektrisch erregten Synchronmaschine\nf\u00a8ur den Einsatz in Elektrofahrzeugen, PhD thesis, Technische\nUniversit\u00a8at Berlin, Germany, 2012.", "H. Karmaker, Stray losses in large synchronous machines, IEEE Transactions\non Energy Conversion, vol. 7. no. 1, March 1992.", "K. Kanelis, Die feldorientierte Kennliniensteuerung der stromerregten\nSynchronmaschine , PhD thesis, Universit\u00a8at der Bundeswehr M\u00a8unchen,\nGermany, 1994.", "K. H. Bayer, H. Waldmann, M. Weibelzahl Die Transvector-Regelung f\u00a8ur\nden feldorientierten Betrieb einer Synchronmaschine, Siemens Zeitschrift,\nHeft 10, 1972."]}

The excellent suitability of the externally excited synchronous machine (EESM) in automotive traction drive applications is justified by its high efficiency over the whole operation range and the high availability of materials. Usually, maximum efficiency is obtained by modelling each single loss and minimizing the sum of all losses. As a result, the quality of the optimization highly depends on the precision of the model. Moreover, it requires accurate knowledge of the saturation dependent machine inductances. Therefore, the present contribution proposes a method to minimize the overall losses of a salient pole EESM and its inverter in steady state operation based on measurement data only. Since this method does not require any manufacturer data, it is well suited for an automated measurement data evaluation and inverter parametrization. The field oriented control (FOC) of an EESM provides three current components resp. three degrees of freedom (DOF). An analytic minimization of the copper losses in the stator and the rotor (assuming constant inductances) is performed and serves as a first approximation of how to choose the optimal current reference values. After a numeric offline minimization of the overall losses based on measurement data the results are compared to a control strategy that satisfies cos (ϕ) = 1.