Minimization of Winding AC Losses Using Inhomogeneous Electrical Conductivity Enabled by Additive Manufacturing

The electrical conductivity (EC) of additively manufactured conductors can be purposely controlled by changing as-built orientation and postprocessing conditions. This feature can be leveraged to minimize winding alternate current (ac) losses in electrical machines adopting solid conductors. This article deals with the additive-manufacturing-based winding design of a high-specific-power permanent-magnet (PM) machine for aerospace applications. Specifically, conductors near slot opening are designed with low EC to reduce winding AC losses, while conductors near slot bottom adopt higher EC to reduce direct current (DC) losses. Parametric finite element models are developed for a thorough design parametric analysis targeting high-specific power as well as high efficiency. The implementation of the proposed coil concept with inhomogeneous EC is discussed and demonstrated. The EC measurements on rod and coil samples are conducted for material characterization.