Additively Manufactured Fe-3si Stator for High-Performance Electrical Motor

Abstract

Additive manufacturing  has the potential to develop novel high-performance electrical machines enabling direct printing of complex shapes and simultaneous processing of multiple feedstocks in a single build to optimize required parameters such as low cost, light weight, low eddy current loss, and high mechanical strength and corrosion resistance. In this work, we report the properties and functional performance of Fe-3wt.%Si material that is printed by selective laser melting, machined down to thin laminates, and stacked to form a stator core of a prototype brushless permanent-magnet electrical motor. Big Area Additive Manufacturing of NdFeB-PPS (Nd2Fe14B-polyphenylene sulfide) bonded cylindrical magnets are magnetized and used for the rotor. The magnetic, mechanical, and electrical properties of the as-printed and various heat-treated thin laminates and the back electromotive force (emf) of the electrical motors at different rotational speeds are measured. The thin laminates exhibit a maximum relative permeability of 7494 at an applied field of 0.8 Oe, and a core loss of about 44 w/kg at 60 Hz with the maximum induction of 15 kG. The measurements for back emf of the assembled electrical motor are compared with the two-dimensional finite element model, which predicts the peak values at various rotational speeds within 25% of the measured values, suggesting the need for more standardized physical parameters for printed magnetic materials and three-dimensional modeling for greater accuracy. The results presented in this work will likely enable the use of advanced manufacturing to realize high-performance complex electrical machine designs by taking advantage of advanced microstructural features that can be investigated to improve the magnetic and mechanical properties.

Keywords: Fe-3wt.% Si, selective laser melting, BAAM isotropic NdFeB PPS magnets, electrical motors, finite element analysis.