Continuous local material model for the mechanical stress-dependency of magnetic properties in non-oriented electrical steel

2019 ◽  
Vol 38 (4) ◽  
pp. 1075-1084 ◽  
Author(s):  
Jan Karthaus ◽  
Silas Elfgen ◽  
Kay Hameyer
Keyword(s):  
Magnetic Properties ◽  
Stress Distribution ◽  
Mechanical Stress ◽  
Electrical Steel ◽  
Material Model ◽  
Electrical Machines ◽  
Magnetic Flux Density ◽  
Content Type ◽  
Local Material ◽  
Stress Dependent

Purpose Magnetic properties of electrical steel are affected by mechanical stress. In electrical machines, influences because of manufacturing and assembling and because of operation cause a mechanical stress distribution inside the steel lamination. The purpose of this study is to analyse the local mechanical stress distribution and its consequences for the magnetic properties which must be considered when designing electrical machines. Design/methodology/approach In this paper, an approach for modelling stress-dependent magnetic material properties such as magnetic flux density using a continuous local material model is presented. Findings The presented model shows a good approximation to measurement results for mechanical tensile stress up to 100 MPa for the studied material. Originality/value The presented model allows a simple determination of model parameters by using stress-dependent magnetic material measurements. The model can also be used to determine a scalar mechanical stress distribution by using a known magnetic flux density distribution.

Mechanical stress distribution and the utilisation of the magneto-elastic effect in electrical machines

2019 ◽  
Vol 38 (4) ◽  
pp. 1085-1097
Author(s):  
Jan Karthaus ◽  
Benedikt Groschup ◽  
Robin Krüger ◽  
Kay Hameyer
Keyword(s):  
Stress Distribution ◽  
Magnetic Flux ◽  
Density Distribution ◽  
Mechanical Stress ◽  
Flux Density ◽  
Electrical Machines ◽  
Magnetic Flux Density ◽  
Content Type ◽  
Elastic Effect ◽  
Flux Density Distribution

Purpose Due to the increasing amount of high power density high-speed electrical machines, a detailed understanding of the consequences for the machine’s operational behaviour and efficiency is necessary. Magnetic materials are prone to mechanical stress. Therefore, this paper aims to study the relation between the local mechanical stress distribution and magnetic properties such as magnetic flux density and iron losses. Design/methodology/approach In this paper, different approaches for equivalent mechanical stress criteria are analysed with focus on their applicability in electrical machines. Resulting machine characteristics such as magnetic flux density distribution or iron are compared. Findings The study shows a strong influence on the magnetic flux density distribution when considering the magneto-elastic effect for all analysed models. The influence on the iron loss is smaller due to a high amount of stress-independent eddy current loss component. Originality/value The understanding of the influence of mechanical stress on dimensions of electrical machines is important to obtain an accurate machine design. In this paper, the discussion on different equivalent stress approaches allows a new perspective for considering the magneto-elastic effect.

Adaptation and parametrization of an iron loss model for rotating magnetization loci in NO electrical steel

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Benedikt Schauerte ◽  
Martin Marco Nell ◽  
Tim Brimmers ◽  
Nora Leuning ◽  
Kay Hameyer
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Electrical Steel ◽  
Electrical Machines ◽  
Iron Loss ◽  
Magnetic Flux Density ◽  
Loss Model ◽  
Content Type ◽  
One Dimensional ◽  
Iron Losses

Purpose The magnetic characterization of electrical steel is typically examined by measurements under the condition of unidirectional sinusoidal flux density at different magnetization frequencies. A variety of iron loss models were developed and parametrized for these standardized unidirectional iron loss measurements. In the magnetic cross section of rotating electrical machines, the spatial magnetic flux density loci and with them the resulting iron losses vary significantly from these unidirectional cases. For a better recreation of the measured behavior extended iron loss models that consider the effects of rotational magnetization have to be developed and compared to the measured material behavior. The aim of this study is the adaptation, parametrization and validation of an iron loss model considering the spatial flux density loci is presented and validated with measurements of circular and elliptical magnetizations. Design/methodology/approach The proposed iron loss model allows the calculation and separation of the different iron loss components based on the measured iron loss for different spatial magnetization loci. The separation is performed in analogy to the conventional iron loss calculation approach designed for the recreation of the iron losses measured under unidirectional, one-dimensional measurements. The phenomenological behavior for rotating magnetization loci is considered by the formulation of the different iron loss components as a function of the maximum magnetic flux density Bm, axis ratio fAx, angle to the rolling direction (RD) θ and magnetization frequency f. Findings The proposed formulation for the calculation of rotating iron loss is able to recreate the complicated interdependencies between the different iron loss components and the respective spatial magnetic flux loci. The model can be easily implemented in the finite element analysis of rotating electrical machines, leading to good agreement between the theoretically expected behavior and the actual output of the iron loss calculation at different geometric locations in the magnetic cross section of rotating electrical machines. Originality/value Based on conventional one-dimensional iron loss separation approaches and previously performed extensions for rotational magnetization, the terms for the consideration of vectorial unidirectional, elliptical and circular flux density loci are adjusted and compared to the performed rotational measurement. The presented approach for the mathematical formulation of the iron loss model also allows the parametrization of the different iron loss components by unidirectional measurements performed in different directions to the RD on conventional one-dimensional measurement topologies such as the Epstein frames and single sheet testers.

Iron loss simulation using a local material model

2019 ◽  
Vol 38 (4) ◽  
pp. 1224-1234
Author(s):  
Benedikt Groschup ◽  
Silas Elfgen ◽  
Kay Hameyer
Keyword(s):  
A Priori ◽  
Material Model ◽  
Edge Length ◽  
Iron Loss ◽  
Local Magnetization ◽  
Content Type ◽  
Local Loss ◽  
Cut Edge ◽  
Iron Losses ◽  
Local Material

Purpose The cutting process of the electric machine laminations causes residual mechanical stress in the soft magnetic material. A local magnetic deterioration can be observed and the resulting local and global iron losses increase. A continuous local material model for the consideration of the changing magnetization properties has been introduced in a previous work as well as an a priori assessment of iron losses. A local iron loss calculation considering both a local magnetization and local loss parameters misses yet. The purpose of this study is to introduce a local iron loss calculation model considering both a local magnetization and local loss parameters. Design/methodology/approach In this paper, an approach for local iron loss simulation is developed and a comparison to the cut-edge length-dependent loss model is given. The comparison includes local loss distribution in the lamination as well as the impact on the overall motor efficiency and vehicle range in an electric vehicle driving cycle. Findings For an analysis of the resulting local iron loss components, both the local magnetization and iron loss parameters must be considered using physically based models. Consistently, a local iron loss model is presented in the work. The developed model can be used to gain detailed information of the local loss distribution inside the machine. The comparability of this local iron loss with the cut-edge length approach for overall system characteristics, e.g. efficiency or driving range, is shown. Originality/value A local iron loss simulation approach is a physical accurate model to describe the influence of cutting techniques on electric machine characteristics. A comparison with the less complicated a priori assessment gives detailed information about the necessity of the local model under consideration of the given problem.

Stress dependent vector magnetic properties in electrical steel

2014 ◽  
Vol 435 ◽  
pp. 25-27 ◽  
Author(s):  
Aphrodite Ktena ◽  
Daniele Davino ◽  
Ciro Visone ◽  
Evangelos Hristoforou
Keyword(s):  
Magnetic Properties ◽  
Electrical Steel ◽  
Dependent Vector ◽  
Stress Dependent

Effect of Antimony on the Structure, Texture and Magnetic Properties of High Efficiency Non-Oriented Electrical Steel

2012 ◽  
Vol 602-604 ◽  
pp. 435-440 ◽  
Author(s):  
Na Li ◽  
Li Xiang ◽  
Pei Zhao
Keyword(s):  
Magnetic Properties ◽  
Magnetic Flux ◽  
Flux Density ◽  
High Efficiency ◽  
Electrical Steel ◽  
Core Loss ◽  
Magnetic Flux Density ◽  
Antimony Content ◽  
The Core ◽  
Maximum Value

The effect of antimony on the structure, texture and magnetic properties of high efficiency non-oriented electrical steel were investigated. The results showed that antimony played an important role on inhibiting the grain growth and enhancing the fraction of favorable texture in the annealed steels. With the increase of antimony content, core loss of specimens monotonously increased and the magnetic flux density increased firstly and then decreased. The magnetic properties of specimen results showed that the magnetic flux density in the steel with 0.12% antimony reached the maximum value, while the core loss didn’t increase obviously. However, when the antimony content in steel reached 0.22%, the magnetic properties deteriorated significantly. This is maybe that the addition of antimony in steels inhibited the development of {111} texture content and increased the intensity of Goss and {100} texture on the grain boundary.

scholarly journals Analysis of Electric Motor Magnetic Core Loss under Axial Mechanical Stress

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6818
Author(s):  
L. Ashok Kumar ◽  
Bagianathan Madhan Raj ◽  
Varadarajan Vijayakumar ◽  
Vairavasundaram Indragandhi ◽  
Vairavasundaram Subramaniyaswamy ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Mechanical Stress ◽  
Experimental Evaluation ◽  
Research Work ◽  
Core Loss ◽  
Magnetic Core ◽  
Iron Loss ◽  
Magnetic Flux Density ◽  
Electrical Machine ◽  
Axial Pressure

The electrical machine core is subjected to mechanical stresses during manufacturing processes. These stresses include radial, circumferential and axial components that may have significant influence on the magnetic properties and it further leads to increase in iron loss and permeability in the stator core. In this research work, analysis of magnetic core iron loss under axial mechanical stress is investigated. The magnetic core is designed with Magnetic Flux Density (MF) ranging from 1.0 T to 1.5 T with estimated dimensions under various input voltages from 5 V to 85 V. Iron losses are predicted by the axial pressure created manually wherever required and is further applied to the designed magnetic core in the range of 5 MPa to 50 MPa. Finite element analysis is employed to estimate the magnetic core parameters and the magnetic core dimensions. A ring core is designed with the selected dimensions for the experimental evaluation. The analysis of iron loss at 50 Hz frequency for non-oriented electrical steel of M400-50A is tested experimentally using the Epstein frame test and force-fit setup test. Experimental evaluation concludes that the magnetic core saturates when it reaches its knee point of the B-H curve of the chosen material and also reveals that the axial pressure has a high impact on the magnetic properties of the material.

Effect of mechanical stress on different iron loss components up to high frequencies and magnetic flux densities

2017 ◽  
Vol 36 (3) ◽  
pp. 580-592 ◽  
Author(s):  
Jan Karthaus ◽  
Simon Steentjes ◽  
Nora Leuning ◽  
Kay Hameyer
Keyword(s):  
Mechanical Stress ◽  
Electrical Steel ◽  
Mechanical Stresses ◽  
Iron Loss ◽  
Content Type ◽  
High Frequencies ◽  
Steel Sheets ◽  
Iron Losses ◽  
Loss Component ◽  
Electrical Steel Sheets

Purpose The purpose of this paper is to study the variation of the specific iron loss components of electrical steel sheets when applying a tensile mechanical load below the yield strength of the material. The results provide an insight into the iron loss behaviour of the laminated core of electrical machines which are exposed to mechanical stresses of diverse origins. Design/methodology/approach The specific iron losses of electrical steel sheets are measured using a standardised single-sheet tester equipped with a hydraulic pressure cylinder which enables application of a force to the specimen under test. Based on the measured data and a semi-physical description of specific iron losses, the stress-dependency of the iron loss components can be studied. Findings The results show a dependency of iron loss components on the applied mechanical stress. Especially for the non-linear loss component and high frequencies, a large variation is observed, while the excess loss component is not as sensitive to high mechanical stresses. Besides, it is shown that the stress-dependent iron loss prediction approximates the measured specific iron losses in an adequate way. Originality/value New applications such as high-speed traction drives in electric vehicles require a suitable design of the electrical machine. These applications require particular attention to the interaction between mechanical influences and magnetic behaviour of the machine. In this regard, knowledge about the relation between mechanical stress and magnetic properties of soft magnetic material is essential for an exact estimation of the machine’s behaviour.

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