Additively Manufactured Hollow Conductors for High Specific Power Electrical Machines: Aluminum vs Copper

The objective of this paper is to compare two materials available for additive manufacturing (AM) of hollow conductors – aluminum and copper alloys. The specific types of aluminum and copper alloys used in this comparison are AlSi10Mg and CuCr1Zr, which can be processed through direct metal laser sintering (DMLS). Compared to pure aluminum or copper in terms of additive manufacturing, AlSi10Mg and CuCr1Zr parts have better mechanical properties, and manufacturability despite their lower electrical conductivities (ECs). The comparison has been focused on manufacturing limitation (price, built area, tolerances, etc.), electrical properties and thermal performance, highlighting the feasibility of using them for building stator windings with integrated direct cooling. A 250 kW, 5000 r/min high-specific-power permanent-magnet (PM) machine is adopted to highlight the pros and cons of the two approaches. Coil trials and manifolds are manufactured and assembled to show the feasibility of the design. Finally, material characterization is performed to verify the material properties of the additively manufactured coils.