Evaluation of 3D Printed Cobalt Iron Cores for Filter Inductors

Abstract

This paper presents a timely report on 3D printed Cobalt Iron (CoFe) soft magnetic cores enabled by the latest advances of additive manufacturing technologies. The feasibility of 3D printing CoFe magnetic cores is demonstrated in a current-ripple-filtering line inductor for power electronics applications. A like-for-like comparison is conducted between the 3D printed solid core and a commercial laminated core with the identical outer geometries to benchmark the former. Performance of the cores is evaluated based on assembled inductors regarding two key high-frequency characteristics, the inductance and the core losses. The results show that the effective permeability of the 3D printed core reduces rapidly with the increase of frequency, due to the low effective resistivity and consequently prominent eddy currents. When the functional equivalent is achieved, i.e. the same inductance for filtering switching-frequency current ripples, the inductor with 3D printed CoFe cores shows five times larger core losses compared to the commercial laminated core.

Applications and Future of Automated and Additive Manufacturing for Power Electronics Components and Converters

“…Generally, DMLS and SLM both provide high metal forming quality and excellent metal performance, making them good choices for manufacturing metal structures. Plenty of metal and alloy components on power electronics and power converters are made using these techniques, such as 3D-printed windings [28], [29], magnetic parts [30] and metal heat sinks [31], [32].…”

“…Test results show that the printed core has excellent low-frequency performance with the permeability of >10 000 at 50 Hz. Though its high-frequency performance reduces significantly with frequency increasing, its short lead time and flexible structure enable applications in the power electronics industry [30].…”

The Mitigation of Eddy-Current Losses in Ferromagnetic Samples Produced by Laser Powder Bed Fusion

“…In order to get good electromagnetic properties, thermal post-processing is required after the printing process [7]. However, though initial demonstrations exist [8], the current PBF-LB technology has limitations in producing thin electrically insulated structures, and therefore, the PBF-LB manufactured cores are typically solid, leading to excessive eddy-current losses, especially at high frequencies [9].…”