Design Trade-off and Experimental Validation of multiphase starter generators for 48V mini-hybrid powertrain

In this paper the principal design aspects of a 48 V belt driven starter-generator for mini-hybrid automotive application are presented and discussed. Starting from the same specifications, two different 10 kW water-cooled induction machines have been designed and produced. Both the prototypes use the same stator design having a double three-phase stator winding made with solid bar conductors. The difference between the two machines is the rotor, which is designed with closed slots in the first prototype and open slots in the second one. The aim is to investigate the trade-off between electromagnetic performance and mechanical issues due to the 20000 rpm maximum rotating speed. The experimental verification of the electromagnetic performance and stator windings short time thermal transient behavior are reported too.