Slot Water Jacket Cooling System for Traction Electrical Machines with Hairpin Windings: Analysis and Comparison

This work aims to analyze and compare the electromagnetic and thermal behavior of two commonly used electrical machines in the automotive field: an induction motor and a brushless permanent magnet one, here equipped with slot water jacket cooling systems. The same stator design, drive management, and winding layout, with hairpin conductors, are adopted for both machines. Four different slot cooling system design arrangements are investigated, keeping the same overall machine volume. Both motors are simulated with the proposed cooling system arrangements. Loss analyses are carried out to evaluate the impact of the different channel positioning inside the slot and their effects on the electromagnetic performance. In the end, the best cooling solution is identified for each machine, highlighting the main differences between the two machines' behavior, in addition to proving the cooling system topology goodness for hairpin windings machines in the automotive sector.