Experimental & Modelling Study of Advanced Direct Coil Cooling Methods in a Switched Reluctance Motor

The development of the next generation electrical vehicles requires drive-trains to become more compact, high-performant, and robust at the lowest possible cost. These more compact drive-trains operate at the same power ratings as their bigger sized equivalent and do need to dissipate their heat in a smaller volume. Therefore, more advanced liquid cooling methods of the drive-train components are needed to enhance the heat removal and increase the compactness, i.e., power density. Till now, most advanced cooled switched reluctance motors (SRM) of such drive-trains use already liquid cooling, i.e., Water& Glycol (WG) in a jacket. However, this liquid cooling method has only an indirect contact with the coils of the motor, i.e., is limited in thermal performance. Therefore, this paper studies direct coil cooling methods and specifically the direct oil jet cooling approach in terms of power density increase experimentally. In addition, the challenge of validating properly the experimental data of several innovative direct coil cooling concepts by commercial software packages will be discussed in the paper.