Authors: Patrick Kühn, Yangyiwei Yang, Guanyu Chen, Shanelle N. Foster, Herbert Egger, Bai-Xiang Xu

Improving the efficiency of electrical machines requires a fundamental understanding of the mechanisms that govern magnetic and eddy-current losses in magnetic core materials, which are inherently controlled by the microstructural features. With FeSi alloys serving as a representative model system, this work assesses both hysteresis and eddy-current losses in additively manufactured electrical steel using a multiphysical framework that combines the demagnetization simulation based on the Landau–Lifshitz theory and the computational homogenization based on the magneto-quasi-static (MQS) Maxwell’s equations. The microstructures were digitized and generated from experimental characterization of the additively manufactured FeSi electric steel with different Silicon and Boron contents. By conducting parameter studies on a series of digital microstructures, the effects of average grain size and grain boundary (GB) phase thickness on hysteresis and eddy-current losses were revealed. An average grain size around 120 μm has the lowest hysteresis loss, although the eddy-current loss increases with the grain size. Increasing GB-phase thickness helps reduce both losses. Results indicate the potential to reduce energy losses in magnetic core materials through microstructural optimization.