Thermal analysis of switched reluctance motor with direct in-winding cooling system

Demand for compact high torque/power density electric machines necessitates the choice of an effective cooling system. The focus of this paper is to compare the steady-state thermal analysis of a naturally air-cooled conventional 8/6 SRM to the same motor with direct in-winding cooling system. The goal is to determine how much torque increase can be achieved by using direct cooling in the windings slots. The results show that the direct cooling of the winding guarantees lower temperature in the windings by 50% at a given operating point, although the winding slot volume is reduced by 25%. This means current density limit increases with direct winding cooling, hence improving the torque/power density of the machine.