Design and Analysis of Stator Cooling Channels for an Axial-Flux Permanent Magnet Machine

Axial-flux permanent magnet (AFPM) machines are preferred for applications with space limitations due to their high power and torque densities. However, these higher densities lead to increased temperatures due to the higher output power, which results in more losses, in a smaller volume. Reducing the thermal resistance between the heat generating components and the cooling system improves the thermal performance of the machine. This work compares the effectiveness of different cooling designs that are integrated into the stator potting. The heat generated in the stator that needs to be rejected is produced from the copper, core, and bearing losses. The effect of various design parameters on the maximum winding temperature and the pressure drop, if applicable, are also investigated. It was found that the stator potting material has the largest impact on the coil temperature, with a reduction of 17°C seen by improving the thermal conductivity of the material.