Stray-field Loss Research Articles

Modeling and validation of stray-field loss inside magnetic and non-magnetic components under harmonics-DC hybrid excitations based on updated TEAM Problem 21

Purpose This paper aims to propose and establish a set of new benchmark models to investigate and confidently validate the modeling and prediction of total stray-field loss inside magnetic and non-magnetic components under harmonics-direct current (HDC) hybrid excitations. As a new member-set (P21e) of the testing electromagnetic analysis methods Problem 21 Family, the focus is on efficient analysis methods and accurate material property modeling under complex excitations. Design/methodology/approach This P21e-based benchmarking covers the design of new benchmark models with magnetic flux compensation, the establishment of a new benchmark measurement system with HDC hybrid excitation, the formulation of the testing program (such as defined Cases I–V) and the measurement and prediction of material properties under HDC hybrid excitations, to test electromagnetic analysis methods and finite element (FE) computation models and investigate the electromagnetic behavior of typical magnetic and electromagnetic shields in electrical equipment. Findings The updated Problem 21 Family (V.2021) can now be used to investigate and validate the total power loss and the different shielding performance of magnetic and electromagnetic shields under various HDC hybrid excitations, including the different spatial distributions of the same excitation parameters. The new member-set (P21e) with magnetic flux compensation can experimentally determine the total power loss inside the load-component, which helps to validate the numerical modeling and simulation with confidence. The additional iron loss inside the laminated sheets caused by the magnetic flux normal to the laminations must be correctly modeled and predicted during the design and analysis. It is also observed that the magnetic properties (B27R090) measured in the rolling and transverse directions with different direct current (DC) biasing magnetic field are quite different from each other. Research limitations/implications The future benchmarking target is to study the effects of stronger HDC hybrid excitations on the internal loss behavior and the microstructure of magnetic load components. Originality/value This paper proposes a new extension of Problem 21 Family (1993–2021) with the upgraded excitation, involving multi-harmonics and DC bias. The alternating current (AC) and DC excitation can be applied at the two sides of the model’s load-component to avoid the adverse impact on the AC and DC power supply and investigate the effect of different AC and DC hybrid patterns on the total loss inside the load-component. The overall effectiveness of numerical modeling and simulation is highlighted and achieved via combining the efficient electromagnetic analysis methods and solvers, the reliable material property modeling and prediction under complex excitations and the precise FE computation model using partition processing. The outcome of this project will be beneficial to large-scale and high-performance numerical modeling.

Calculation and validation of stray‐field loss in magnetic and non‐magnetic components under harmonic magnetizations based on TEAM Problem 21

On the basis of the TEAM problem 21 benchmark model, a modelling method to predict stray-field loss under real working conditions is presented and validated to investigate the influence of harmonic excitation on stray-field loss of shielding structural components of converter transformers in high-voltage direct current systematically. An improved method is adapted to determine stray-field loss of magnetic and non-magnetic component based on the experimental measurement and numerical simulation. An experimental platform is established to measure magnetic properties and loss characteristics of the grain-oriented silicon steel sheets, aiming at parameter identification and verification of the loss modelling applicable for laminated sheets under harmonic magnetisation. Meanwhile, the additional iron loss caused by perpendicular flux penetration is obtained by special treatment of material properties and analysed to observe its contribution to the stray-field loss under three-dimensional harmonic magnetisation. Field and loss comparison between measurement and simulation verifies the validation of the proposed modelling method.

Improved Evaluation of Magnetic Loss Inside Silicon Steel Laminations Under 3-D Multi-Harmonic Magnetizations

An improved method is presented to study the efficient numerical modeling of stray-field loss in magnetic shielding excited by a 3-D harmonic magnetic field. The experimental platform is established to obtain the magnetic properties and loss model of the silicon steel lamination under harmonic magnetizations. Experimental determination is improved for more accurate stray-field loss based on the engineering-oriented model TEAM Problem 21c-M1. Prediction and evaluation of stray-field loss and additional iron loss due to harmonic excitations are achieved by special treatment of material properties in the numerical calculation of the harmonic magnetic field.

Stray-field loss and flux distribution inside magnetic steel plate under harmonic excitation

PurposeThis paper aims to investigate an efficient approach to model the electromagnetic behaviors and predict stray-field loss inside the magnetic steel plate under 3D harmonic magnetization conditions so as to effectively prevent the structural components from local overheating and insulation damage in electromagnetic devices.Design/methodology/approachAn experimental setup is applied to measure all the magnetic properties of magnetic steel plate under harmonic excitations with different frequencies and phase angles. The measurement and numerical simulation are carried out based on the updated TEAM Problem 21 Model B+ (P210-B+), under the 3D harmonic magnetization conditions. An improved method to evaluate the stray-field loss is proposed, and harmonic flux distribution in the structural components is analyzed.FindingsThe influence of the harmonic order and phase angle on the stray-field loss in magnetic steel components are noteworthy. Based on the engineering-oriented benchmark models, the variations of stray-field losses and magnetic field distribution inside the magnetic components under harmonic magnetization conditions are presented and analyzed in detail.Research limitations/implicationsThe capacity of the multi-function harmonic source, used in this work, was not large enough, which limits the magnetization level. Up to now, further improvements to increase the harmonic source capacity and investigations of the electromagnetic behaviors of magnetic steel components under multi-harmonic and DC-AC hybrid excitations are in progress.Originality/valueTo accurately predict the stray-field loss in magnetic steel plate, the improved method based on the combination of magnetic measurement and numerical simulation is proposed. The effects of the frequency and phase angle on the stray-field loss are analyzed.

Simulation Analysis and Benchmarking Validation of Magnetic, Electromagnetic and Hybrid Shields in Large Power Transformers

according to different theories the magnetic shunt, the electromagnetic shield and a combination of both in power transformer have protective shielding functions to mental components and decrease stray-field loss ( including eddy current loss and hysteresis loss), avoiding damage to insulation devices caused by partial overheating for overconcentration of the loss. This paper will build a 2D modeling and simulation which proves the improved platform measuring the the shield loss and flux density of the transformer product model can provide a more reasonable flux complementary condition. Three kinds of shield in the model will be calculated by 3-D model simulation to research and compare the loss and flux density of the magnetic shunt, the electromagnetic barrier and the hybrid shield, which is of significant analyzable and referable value for optimizing the design of magnetic shields in large power transformers.

3-D Finite Element Modeling and Validation of Power Frequency Multishielding Effect

The electromagnetic (EM) barrier, the magnetic (M) shunt and a combination of both are widely used in electrical devices in order to control stray fields and effectively reduce the power loss that may lead to hazardous local overheating. This paper focuses on the 3-D finite element modeling and validation of multishielding at power frequencies. The hybrid (M+EM) shielding behavior of the current magnetic shunt configuration is numerically and experimentally examined and is compared to other types. The leakage flux complementary-based measurement method of stray-field loss is also proposed and verified based on the benchmark shielding models.

Eddy Current and Loss Analysis of Multisteel Configuration and Validation

Three-dimensional nonlinear eddy current and stray-field loss analysis of multisteel configurations based on TEAM Problem 21 family and the related validation are presented. Some extended investigations to Problem 21, referred to as postbenchmarking, are outlined. The newly measured and calculated results of both the magnetic field and the stray-field loss illustrate the electromagnetic behavior of the prototype model. It is indicated that the power loss distribution in the multisteel parts closely depends on the material configuration and the applied fields

Loss spectrum and electromagnetic behavior of problem 21 family

A set of both the magnetic and electromagnetic shielding models, referred to as a new member of the Problem 21 family, is proposed to investigate the shielding effects of different kinds of shields. This paper presents the newly measured and calculated results of both the magnetic field and stray-field loss concerning the TEAM-based models to detail the electromagnetic behavior of the Problem 21 family, evaluates the engineering applicability of three-dimensional eddy current analysis methods, and validates the engineering effectiveness of the practical loss modeling proposed by the authors

Nonlinear analysis of eddy current and hysteresis losses of 3-D stray field loss model (Problem 21)

The evaluation method of stray field loss of engineering oriented loss model (TEAM Workshop Problem 21) is investigated. It is shown that the nonlinear eddy current analysis is obligatory in order to investigate the eddy current loss in the steel plate, because the flux and eddy current in steel are affected by the permeability of the plate. The hysteresis loss in such a steel plate having a substantial skin effect is not negligible, even if the flux density in air is small.