Empirical Implementation of the Steinmetz Equation to Compute Eddy Current Loss in Soft Magnetic Composite Components

Abstract

Finite element analysis of magnetic materials allows accurate prediction of losses and is crucial in the design of electromagnetic devices and products. Soft magnetic composites are an alternative to silicon steel laminations, yet the electromagnetic material properties are less well documented and include uncertainties which can lead to inaccurate iron and Joule loss computations. The microstructure of soft magnetic composites, which is based on ferromagnetic particles coated by inorganic resistive insulation, makes the process of iron loss prediction unique. Composite core materials require further attention by design engineers in terms of the effect of component size and pressing processes on core loss predictions, which for laminations uses the well-known Steinmetz law. This study accesses the existing soft magnetic composite core loss modelling trends using experimentally measured results. The challenges of estimating and using Steinmetz core loss coefficients via curve fitting approaches are discussed. The study indicates that soft magnetic composite components need to be treated differently to laminated iron cores. Modelling the composite materials in finite element software requires experimentally informed loss models to be able to accurately compute power losses under varying magnetic flux density and electrical frequency. An approach is suggested which can predict iron losses to within 7%, but is only validated for component cross sectional areas of 144 mm 2 or less.

Analysing and Computing the Impact of Geometric Asymmetric Coils on Transformer Stray Losses

“…This strategic separation and focused analysis enhances the precision in evaluating the distinct contributions of hysteresis, eddy and excess losses in the transformer tank walls. The hysteresis loss density (Watts/m 3 ) in each of the tank walls will be given by the Steinmetz equation [23]:…”

Magnetic-Thermal-Flow Field Coupling Simulation of Oil-Immersed Transformer

“…The Steinmetz model mainly considers the relationship between core loss density and material properties, magnetization frequency, and magnetic flux density amplitude. The Steinmetz equation is given as follows [18] 𝑊 𝑖 = 𝐾 ℎ 𝑓 𝛼 𝐵 𝑚 𝛽 (1) where Wi is the core loss density, Kh, α and β are the loss coefficient, f is the frequency of magnetic flux density variation, Bm is the largest magnetic flux density. The magnetic flux density is mainly decided by the magnetic iron, and the equation shows that the iron core loss varies linearly with the frequency.…”

Design and FEM Analysis of High-Torque Power Density Permanent Magnet Synchronous Motor (PMSM) for Two-Wheeler E-Vehicle Applications

“…e component K h f α B β is referred to as the Steinmetz loss, which is a combination of the hysteresis and the anomalous loss, whereas the component K e (sfB) 2 is referred to as the eddy-current loss. Using the Steinmetz equation, the core loss is computed at any peak flux density for the specified fundamental frequency [25]. Similarly, the copper losses in the hub-motor are mathematically formulated by the following equation [26]:…”

“…e electromagnetic torque developed by the PMSM is given by equation ( 23). e input power drawn by the hubmotor under the balanced conditions is formulated by equation ( 24), and the output mechanical power is given by equation (25). Equation ( 26) defines the overall efficiency computation of the PMSM under the rated loaded conditions [29].…”