Thermal Analysis of Novel Winding Structures for the Usage in Electrical Machines

In the design process of high-power density machines, the thermal behavior is becoming increasingly important. Therefore, a novel compact winding process for round wires is developed to combine the advantage of a high filling factor of rectangular wires and the advantage of low high-frequency losses of round wires. This is achieved with compacting round wires, which refers to compressing and pressing the windings.In this contribution, we present different analytical approaches to approximate the thermal conductivity of the slot and compare them with a numerical approach. The measured thermal conductivity of the compact winding is increased by a maximum of 15.6% compared to a random wound winding, which increases the continuous and peak power operation and showing the importance of novel winding methods. Additionally it is shown that the calculated thermal conductivity increases if one increases the wire diameter. The measurements show good accordance to the simulation results.