Performance Evaluation of Electrically Excited Synchronous Machine compared to PMSM for High-Power Traction Drives

Paper in proceeding, 2020

The electric drive design for heavy-duty vehicles ischallenging due to special requirements involved, such as highstarting torque and operation at the peak power for a longtime. The electrically excited synchronous machine (EESM) is asuitable machine type for such an application and a potentialalternative to the permanent magnet synchronous machines(PMSM) due to the superior flexibility that the control of thebrushless rotor excitation offers. The direct adjustment of theflux allows also to tune the best efficiency region of the machineclose to the usual operating points of the vehicle achieving at thesame time a better power factor compared to a PMSM, whichcan further increase the efficiency and the power capability ofthe stator inverter. A case-study comparison of a EESM- andPMSM-based drive for electric trucks is presented in this paperwhere Finite-Element-Method and Matlab simulations of thewhole vehicle drivetrain showcase the advantages of the EESM.