Performance Evaluation of Electrically Excited Synchronous Machine compared to PMSM for High-Power Traction Drives
Georgios Mademlis, Yujing Liu, Junfei Tang, Luca Boscaglia, Nimananda Sharma
Abstract
The electric drive design for heavy-duty vehicles is challenging due to special requirements involved, such as high starting torque and operation at the peak power for a long time. The electrically excited synchronous machine (EESM) is a suitable machine type for such an application and a potential alternative to the permanent magnet synchronous machines (PMSM) due to the superior flexibility that the control of the brushless rotor excitation offers. The direct adjustment of the flux allows also to tune the best efficiency region of the machine close to the usual operating points of the vehicle achieving at the same time a better power factor compared to a PMSM, which can further increase the efficiency and the power capability of the stator inverter. A case-study comparison of a EESM-and PMSM-based drive for electric trucks is presented in this paper where Finite-Element-Method and Matlab simulations of the whole vehicle drivetrain showcase the advantages of the EESM.