Comparative study of copper and aluminium conductors - future cost-effective PM machines

This presentation investigates the use of aluminium (Al) as an alternative to the more common copper (Cu) conductors used in the construction of future cost-effective PM machines. The use of Al conductors in the context of PM machine design has not been widely explored or reported in the literature. The main focus of this research has been placed on the power loss generated at AC operation and associated thermal and heat transfer phenomena, which are essential to understand when a compact and efficient machine design utilising Al conductors is considered. The AC winding loss component depends on the winding electrical resistivity in a different manner than that at DC operation. Elevated electrical resistivity of the winding is caused either by the winding temperature rise and/or the winding material used, e.g. Al, and results in the AC winding power loss component to be reduced. However, the overall winding power loss at AC operation is dependent on both AC and DC power loss components, therefore careful design considerations must be taken in order to fully utilise physical properties of the conductor material. To illustrate the importance of these effects, a number of hardware exemplars have been evaluated using both experimental and theoretical approaches. The initial results suggest that Al might be an interesting alternative to the more common Cu conductors for some PM machine applications.