Properties Of Electrical Steel Sheets Research Articles

Simulation of the Effects of Weld-Packaging on the Electromagnetic Properties of Electrical Steel Sheets Using a Local Varying Material Model

Simulation of the Effects of Weld-Packaging on the Electromagnetic Properties of Electrical Steel Sheets Using a Local Varying Material Model

Effect of Si Content on Magnetostrictive Properties of Electrical Steel Sheet Considering Tensile Stress

Effect of Si Content on Magnetostrictive Properties of Electrical Steel Sheet Considering Tensile Stress

Basic properties of ferromagnetic vector hysteresis play models and their validation by finite element method

PurposeMagnetic hysteresis holds significant technical and physical importance in the design of electromagnetic components. Despite extensive research in this area, modeling magnetic hysteresis remains a challenging task that is yet to be fully resolved. The purpose of this paper is to study vector hysteresis play models for anisotropic ferromagnetic materials in a physical, thermodynamical approach.Design/methodology/approachIn this work, hysteresis play models are implemented to interpret magnetic properties, drawing upon classical rate-independent plasticity principles derived from continuum mechanics theory. By conducting qualitative and quantitative verification and validation, various aspects of ferromagnetic vector hysteresis were thoroughly examined. By directly incorporating the hysteresis play models into the primal formulations using fixed point method, the proposed model is validated with measurements in a finite element (FE) environments.FindingsThe proposed vector hysteresis play model is verified with fundamental properties of hysteresis effects. Numerical analysis is performed in an FE environment. Measured data from a rotational single sheet tester (RSST) are validated to the simulated results.Originality/valueThe results of this work demonstrates that the essential properties of the hysteresis effects by electrical steel sheets can be represented by the proposed vector hysteresis play models. By incorporation of hysteresis play models into the weak formulations of the magnetostatic problem in the h-based magnetic scalar potential form, magnetic properties of electrical steel sheets can be locally analyzed and represented.

Comparison of a quasi Newton method using Broyden’s update formula and an adjoint method for determining local magnetic material properties of electrical steel sheets

PurposePerforming accurate numerical simulations of electrical drives, the precise knowledge of the local magnetic material properties is of utmost importance. Due to the various manufacturing steps, e.g. heat treatment or cutting techniques, the magnetic material properties can strongly vary locally, and the assumption of homogenized global material parameters is no longer feasible. This paper aims to present the general methodology and two different solution strategies for determining the local magnetic material properties using reference and simulation data.Design/methodology/approachThe general methodology combines methods based on measurement, numerical simulation and solving an inverse problem. Therefore, a sensor-actuator system is used to characterize electrical steel sheets locally. Based on the measurement data and results from the finite element simulation, the inverse problem is solved with two different solution strategies. The first one is a quasi Newton method (QNM) using Broyden's update formula to approximate the Jacobian and the second is an adjoint method. For comparison of both methods regarding convergence and efficiency, an artificial example with a linear material model is considered.FindingsThe QNM and the adjoint method show similar convergence behavior for two different cutting-edge effects. Furthermore, considering a priori information improved the convergence rate. However, no impact on the stability and the remaining error is observed.Originality/valueThe presented methodology enables a fast and simple determination of the local magnetic material properties of electrical steel sheets without the need for a large number of samples or special preparation procedures.

Measurement of magnetic properties of grain-oriented electrical steel considering multi-physics factors influence

The magnetic properties of electrical steel sheets are strongly affected by the Multi-Physics Factors (MPF), such as bending stress, working temperature, and magnetization patterns. To investigate the complex magnetic properties of the material under MPF magnetizing conditions, a magnetic property measurement system is first developed, considering the effect of bending stress, temperature loading, and non-sinusoidal magnetization waveforms. Then, the magnetic and the loss properties of Grain-Oriented (GO) electrical steels under MPF magnetizing conditions are measured and discussed. Obtained results showed that bending stress and non-sinusoidal magnetization waveforms are positively correlated with the loss properties of electrical steel sheets, and elevated temperatures can mitigate the effects of bending stress and harmonics on magnetic properties and losses.

Measurement of the Vector Magnetic Property of Electrical Steel Sheet Under Triaxial Stress

Measurement of the Vector Magnetic Property of Electrical Steel Sheet Under Triaxial Stress

Temperature Rise Calculation of Magnetic Core Considering the Temperature Effect of Magnetic Properties in an Electrical Steel Sheet

The magnetic properties of electrical steel sheets are affected by magnetization patterns, working temperature, and external pressure. In order to study the temperature effect of electrical steel sheets on the temperature rise of a transformer core, in this paper, based on the magnetic property test system of an electrical steel sheet, the permeability and loss of a 50AW600 grain non-oriented electrical steel sheet and a 30ZH120 grain oriented electrical steel sheet under different temperatures and excited frequencies were measured, and the influence of temperature on the properties of the material was analyzed. A magneto-thermal iterative coupling method considering the temperature effects of magnetic properties in the electrical steel sheet was investigated. Based on the above measurement data and iterative coupling method, the temperature distribution of the core of a 500-kV power transformer was simulated and analyzed, and compared with the simulation results of the traditional coupling method without considering the temperature effect of the electrical steel sheet. Magneto-thermal coupling simulation under no-load operation is a symmetrical problem. It was found that the temperature of the hottest spot of the transformer core calculated by the magneto-thermal iteration method proposed in this paper was significantly reduced, the temperature of the hottest spot on the core column was about 45 °C, and the temperature of the hottest spot on the upper and lower yoke was about 39 °C, which provides an effective simulation method for accurately calculating the temperature rise distribution of electrical products such as transformers.

Vector Magnetic Properties of Electrical Steel Sheet Under DC-Biased Flux and Rotating Magnetic Fields of Varying Frequencies

In this study, we explore the vector magnetic properties of the electrical steel sheet under dc-biased flux and rotating magnetic field of different frequencies. The corresponding iron loss and the rotational eddy current loss are discussed. An enhanced vector magnetic hysteresis model is proposed to describe the B- H behavior under these conditions. The accuracy of the proposed model is verified by the close agreement between the hysteresis loops calculated with the proposed model and those measured experimentally, as well as by the neglectable calculation error of the total iron loss.

Two-Dimensional AC Magnetic Properties of Electrical Steel Sheet with Two-Dimensional DC-Biased Magnetization

To estimate the magnetic properties with two-dimensional AC-magnetization with two-dimensional DC-biased magnetization, three different grades of non-oriented electrical steel sheets with two-dimensional DC-biased magnetization were prepared. As a result, in the high grade specimen, the difference in the magnetic properties depending on the excitation direction (AC excitation direction is parallel to DC excitation direction) was larger than in the low grade specimen, and the magnetic properties were the best when the excitation direction was the rolling direction. Non-oriented electrical steel sheets have small magnetic anisotropy. High grade non-oriented electrical steel sheets have a large magnetic anisotropy to compare with low grade non-oriented electrical steel sheets. It is thought that magnetic anisotropy increased in the high grade non-oriented electrical steel sheets because the B-H loops under DC-biased magnetization were minor loops. In addition, the increase rate of the H widths and the increase rate of the iron losses depending on the excitation direction were relatively consistent. Since the iron loss is proportional to the area of the B-H loop, it is considered that the iron loss increased at the same rate as the H width of the B-H loop.

Finite Element Analysis of the Magneto-Mechanical Coupling Due to Punching Process in Electrical Steel Sheet

In this article, a finite element (FE) modeling of the punching effect on the magnetic properties of electrical steel sheet is carried out. For that, the modified anhysteretic Sablik model is applied together with the plastic strain distribution obtained from a punching process simulation performed using the software ABAQUS. First, a synchronous electrical machine is simulated including the effect of the punching process, and it shows the degradation of the magnetic flux density at the lamination edges and an increase of the iron losses. Then, results obtained from the magneto-mechanical simulation are investigated in terms of the method used to implement the plastic strain distribution in the FE computation. Two examples have been investigated: a square steel sheet and a tooth of an electrical machine.

Measurement of Stress and Temperature Dependent Vector Magnetic Properties of Electrical Steel Sheet

In addition to the excitation condition, the magnetic properties of electrical steel sheet (ESS) also depend on stress and temperature. This article proposes one systematic measurement method of measuring the vector magnetic properties (VMPs) of ESS. In the proposed method, the coupling effect of temperature and stress are considered. The uniform magnetic field distribution is generated in the measurement area of the specimen using a vertical-type orthogonal double-U shaped yoke. Since the specimen is cross shaped, the mechanical stress can be applied conveniently. The B-probe method and the double compound H-coil method are adopted to measure vector magnetic flux density ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</i> ) and magnetic field intensity ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</i> ). Moreover, the vector B-H sensor is assembled into a ceramic frame from within, which can withstand high temperature. A linear actuator can apply tensile or compressive stress along the rolling direction and transverse direction of the specimen. The variable temperature measurement conditions are achieved by a temperature controller and ceramic heating sheets. The stress and temperature dependent VMPs of nongrain oriented ESS and grain-oriented ESS are measured to verify the effectiveness of the proposed measurement method. The change regulation of VMPs with temperature and stress is summarized.

Modified-SST for Uniaxial Characterization of Electrical Steel Sheets Under Controlled Induced Voltage and Constant Stress

This article details the development of a uniaxial magnetomechanical bench that allows measuring the effect of constant tensile and compressive stress on the magnetic properties of electrical steel sheets. Following international standards for magnetic measurements, this work proposes reasonable modifications of a single-sheet-tester set up to provide a reliable magnetomechanical characterization of the material. The magnetic circuit and the excitation and control techniques employed are described. Specifications concerning magnetic measurements are also offered, alongside mechanical considerations regarding the antibuckling fixture developed to allow the application of compressive stress. Finally, results obtained for various stress levels and frequencies are validated and analyzed. Among other results, the proposed bench allows observing the negative impact of compressive stress on magnetic properties of nonoriented steel, as well as the positive effect of mild tensile stress.

Magnetostrictive Characteristics of the Grain-Oriented Electrical Steel in an Epstein Frame Magnetized with a DC Biased Magnetic Field

The presence of direct current (dc) biased magnetic field enhances the vibration and noise in the transformer cores due to magnetostrictive effect in the grain-oriented electrical steel laminations. Based on an Epstein frame, an experimental setup was built to measure the in-plane magnetostriction, the principal magnetostriction was computed under a dc bias, and the influence of dc bias magnetic field on the magnetostrictive property of electrical steel sheet was investigated. A model based on a back propagation neural network (BPNN) method assisted with the Levenberg–Marquardt algorithm was proposed to describe the magnetostrictive behaviour in the presence of dc bias. Finally, the BPNN model was verified by comparing the measured magnetostriction and the computed one. This research is helpful to make an accurate estimation to deformation of iron core under a dc bias.

Modeling of Anisotropic Magnetostriction Under DC Bias Based on an Optimized BP Neural Network

The existence of direct current (dc) bias magnetic field changes the magnetostrictive properties of electrical steel sheets (ESSs) and intensifies the vibration and noise of transformers. In this article, the dynamic magnetostrictive properties of the ESSs under dc bias are measured and analyzed, and it is shown that the magnetostriction of the ESSs under dc bias has a complex dynamic anisotropy. An optimized backpropagation neural network (BPNN) is proposed to model the dynamic magnetostriction curves under the dc bias. In the construction of the BPNN, the topology is optimized by using the genetic algorithm and the parameters are optimally decided by using particle swarm optimization (PSO), respectively, to get a fast convergence and avoid the local optimal solution. The comparison of the proposed model with experimental measurements shows the accuracy of the proposed model is improved by 6%.

Measurement of high frequency magnetic properties of electrical steel sheet using prototype Rogowski coil

In order to develop a high-efficiency, low-loss, small, high-power, high-speed rotating motor, it is necessary to accurately measure the magnetic properties of electrical steel sheets under PWM excitation. A shunt resistor is generally used for measuring magnetic characteristics, but non-contact current measurement is required. However, iron cores are used in commercially available current measurement sensors, and it is necessary to consider the effects of core characteristics on high-frequency currents. The authors are focusing on Rogowski coils and developing small current / magnetic field sensors specialized for motor and electrical steel sheet evaluation. In this paper, we make a prototype of Rogowski coil, and report on the evaluation of basic electrical characteristics and the results of application to the measurement of magnetic characteristics of electrical steel sheets under sinusoidal excitation and PWM excitation.

The comparison of the enhanced integration-type E&amp;S model and the improved dynamic E&amp;S model of electrical steel sheet under DC-biased magnetizing condition

This paper enhanced the integration-type E&amp;S model and the dynamic E&amp;S model for integrating the impact of DC-biased field and eddy current on vector magnetic properties of electrical steel sheet. B and H of electrical steel sheet are measured under DC-biased and rotating fields. Based on the measured results, the databases of reluctivity and hysteresis coefficients of both the enhanced integration-type E&amp;S model and the improved dynamic E&amp;S model are established for predicting H waveform under any given operating condition. By comparing the H waveform calculated by the enhanced integration-type E&amp;S model and the improved dynamic E&amp;S model with the experimental H waveform, it is found that both two models have good reliability and the improved dynamic E&amp;S model has slightly better accuracy than the enhanced integration-type E&amp;S model.

The FEM Calculation Considering Vector Magnetic Properties of Electrical Steel Sheet Under DC-Biased Field

This article proposes an enhanced dynamic vector magnetic hysteresis model for describing the effect of dc-biased field and eddy current on vector magnetic quantities. A governing equation combining the proposed model is derived for finite-element analysis of magnetic characteristics distribution of transformer core under dc-biased excitation. The numerical results of the transformer core by using the enhanced model with consideration of dc-biased excitation and eddy current are compared with the numerical results obtained by using the magnetizing curve. It proves that the proposed model can consider vector magnetic properties and iron loss of electrical steel sheet under both dc-biased and rotating magnetic fields during numerical analysis.

Modeling of Rotating Magnetic Properties of Electrical Steel Sheet Under DC-Biased Field

As the core material of an electrical device, the electrical steel sheet is often under ac and dc-biased magnetizing conditions due to the wide utilization of power electronics. For an accurate description of rotating magnetic properties of electrical steel sheet under the dc-biased field, an improved model considering magnetic hysteresis and nonlinear magnetization characteristics is established. The reluctivity coefficients and hysteresis coefficients of the improved model are calculated from magnetic flux density and magnetic field intensity waveforms measured by the feedback control system. The accuracy and reliability of the improved model are verified by the comparison of the measured and calculated hysteresis loops of electrical steel sheet under the dc-biased field.

Rotating magnetic properties of electrical steel sheet under DC-biased field

Rotating magnetic properties of electrical steel sheet under DC-biased field

The Degradation Depth of Non-grain Oriented Electrical Steel Sheets of Electric Machines Due to Mechanical and Laser Cutting: A State-of-the-Art Review

Literature agrees that cutting may damage the electromagnetic properties of electrical steel sheets, notably along the cut edge. However, statements on the depth of the deterioration vary. An analysis of the various results presented would allow for a better consideration of the material degradation in the modeling of electromagnetic properties of the cut steel sheet in electric machines. To this aim, this paper analyzes and summarizes the deterioration depths presented in the literature. It not only provides an overview of the quantitative results, but discusses these in the context of the respective measurement method, since every technique used only provides an image of some of the aspects of the cut material affected by the cutting process.