Cooling System Design of a High-Speed Radial-Flux Permanent Magnet Machine for Aerospace Propulsion Applications

Load constraints in aerospace propulsion applications are driving great attention towards research and development of high-speed electric machines. A major focus area for such machines is a cooling system that is reliable and efficient. In this work the cooling system of a high-speed radial-flux surface-mount permanent magnet synchronous motor is presented. The method of modeling the motor and investigating the cooling performance is detailed. The cooling system of the stator of the baseline design consists of encapsulation on the end windings, a cooling duct on the bearings and a cooling jacket housing on the stator laminations. The rotor is cooled by air forced convection by a fan mounted on the shaft. The effect of various design parameters, like coolant flow rate and potting material, on the temperature of the stator and end windings is investigated. The cooling effect obtained by inserting an additional coolant-carrying tube in close proximity to the high heat-generating parts, is also studied.