Thermal Analysis of Air Cooling System for Electric Machines Using Lumped Parameter and Flow Resistance Network

This paper combines lumped parameter thermal network and flow network techniques to perform thermal analysis of electric machine. The method is applied to investigate the efficiency of a novel cooling design for a high-power-density motor based on airflow. A lumped thermal circuit is used to develop a theoretical model for the heat transfer problem of the machine. The 11 nodes and 19 thermal resistance thermal network circuit is used to discretize the heat equation while the 2 node flow network circuit is used to model convection which is fed back in the thermal circuit. The model is compared with numerical computational fluid dynamics simulation, performed on the CAD model of the machine. The machine is rated at 2kW, 40Arms, 15000 min
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with 2 pole-pairs surface permanent magnet.