Hysteresis Measurements and Numerical Losses Segregation of Additively Manufactured Silicon Steel for 3D Printing Electrical Machines

Abstract

Samples from FeSi4 powder were fabricated with a low power selective laser melting (SLM) system using a laser re-melting strategy. The sample material was characterized through magnetic measurements. The study showed excellent DC magnetic properties, comparable to commercial and other 3D printed soft ferromagnetic materials from the literature at low (1 T) magnetization. Empirical total core losses were segregated into hysteresis, eddy and excessive losses via the subtraction of finite element method (FEM) simulated eddy current losses and hysteresis losses measured at quasi-static conditions. Hysteresis losses were found to decrease from 3.65 to 0.95 W/kg (1 T, 50 Hz) after the annealing. Both empirical and FEM results confirm considerable eddy currents generated in the printed bulk toroidal sample, which increase dramatically at high material saturation after annealing. These losses could potentially be reduced by using partitioned material internal structure realized by printed airgaps. Similarly, with regard to the samples characterized in this study, the substantially increased core losses induced by material oversaturation due to reduced filling factor may present a challenge in realizing 3D printed electrical machines with comparable performance to established 2D laminated designs.

A Review on Additive Manufacturing Possibilities for Electrical Machines

“…In addition to the flexibility in geometrical shape realization, [20,21] report high magnetic permeability of up-to 31,000, low hysteresis losses i.e., low coercivity of minimum 16 A/m and up-to 50% weight reduction in AM-built machine core. However increase in eddy currents, due to non-laminated dense structure was also reported [22,23], but this can be decreased significantly with the help of layered structure of different electrical resistivity. The layer-based manufacturing process of AM can also introduce a degree of anisotropy i.e., difference in electromagnetic properties, in build direction compared to other direction.…”

Additive Manufacturing and Performance of E-Type Transformer Core

“…In conventional stampings, the grainoriented pronounced Goss texture can be achieved with various hot and cold rolling stages of the steel sheets. In printed material, the optimization of the material grain structure is largely immature, with some grain structure evolution observed in [13], in heat treated laser-remelted printed silicon steel samples. Several topological improvements can be applied to the transformer for enhanced performance.…”

“…Traditionally, the magnetic material loss behaviour is discussed in terms of cycle peak polarization (B max ) of the core. Unlike in the toroidal cores for magnetic material characterization [6,13], however, the flux density in the investigated transformer core can only be evaluated as an approximation, due to its uneven flux distribution. The analytical expression for calculating the peak polarization in a transformer can be derived from the differential form of Faraday's law (2), where E is the induced electromotive force by the switching magnetic field, N is the number of turns on the primary coil (1370), f is the excitation frequency of the magnetic field (50 Hz), B max is the peak material polarization, S is the core cross sectional area, F is the core filling factor, U is the applied voltage on the primary coil, and U r is the voltage drop over the primary coil.…”

Opportunities and Challenges of Utilizing Additive Manufacturing Approaches in Thermal Management of Electrical Machines

“…As the main objective of this paper is to introduce the capability of the AM method in the advanced thermal management design of electrical machines; More information about the other subjects of additive manufacturing techniques in electrical machines can be found following literatures and references [1], [2], [6], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22] .…”