Due to their high power density and high overall efficiency permanent magnet excited synchronous machines are beneficial to be applied in traction drives of full electric or hybrid-electric vehicles with limited installation space. To improve the performance, additional flux-barriers can be inserted to the rotor of the machine. In this paper, the effects of different flux-barrier positions and sizes are systematically studied. Command variables for the improvement are average torque, torque ripple, total harmonic distortion of the back-emf, iron losses and efficiency.