Vector Hysteresis Model Research Articles

Fast Torque Computation of Hysteresis Motors and Clutches Using Magneto-static Finite Element Simulation

Hysteresis motor and clutches have several advantages, such as constant torque from zero to synchronous speed, low torque ripple, and low fabrication cost. Low efficiency and power factor are the main features that have limited the application of this type of electrical machine to few applications. Being a niche argument, little literature has addressed the problem of analytical and finite element (FE) modelling of hysteresis electrical machines. This paper first describes the most important contributions of the literature on the analytical and FE modelling of hysteresis motors and clutches and then proposes a method for the fast computation of its performance. The proposed procedure consists of two steps: first, a magneto-static FE simulation is performed considering the normal magnetization curve of the hysteresis material; then, the average torque is computed by a post-processing analysis. The proposed method is used to analyze a hysteresis clutch and the obtained results are compared with those achieved using a commercial finite element software that implements a vector hysteresis model.

Comparison of different vector Preisach models for the simulation of ferromagnetic materials

PurposeThe numerical computation of magnetization processes in moving and rotating assemblies requires the usage of vector hysteresis models. A commonly used model is the so-called Mayergoyz vector Preisach model, which applies the scalar Preisach model into multiple angles of the halfspace. The usage of several scalar models, which are optionally weighted differently, enables the description of isotropic as well as anisotropic materials. The flexibility is achieved, however, at the cost of multiple scalar model evaluations. For solely isotropic materials, two vector Preisach models, based on an extra rotational operator, might offer a lightweight alternative in terms of evaluation cost. The study aims at comparing the three mentioned models with respect to computational efficiency and practical applicability.Design/methodology/approachThe three mentioned vector Preisach models are compared with respect to their computational costs and their representation of magnetic polarization curves measured by a vector vibrating sample magnetometer.FindingsThe results prove the applicability of all three models to practical scenarios and show the higher efficiency of the vector models based on rotational operators in terms of computational time.Originality/valueAlthough the two vector Preisach models, based on an extra rotational operator, have been proposed in 2012 and 2015, their practical application and inversion has not been tested yet. This paper not only shows the usability of these particular vector Preisach models but also proves the efficiency of a special stageless evaluation approach that was proposed in a former contribution.

Incorporation of a Vector Preisach–Mayergoyz Hysteresis Model in 3-D Finite Element Analysis

A new formulation of the Preisach–Mayergoyz model was developed to radically improve its numerical performance. This new computationally efficient vector hysteresis model was incorporated in a 3-D finite element software. Many improvements to the transient nonlinear solver were made in order to obtain a good convergence of the TEAM problem 32 while using only 125 time steps per cycle. The results of this simulation show good agreement with the experimental data.

Issue: Selected paper of OIPE 2016 on modeling and optimal design of electromagnetic and electronic devices

Issue: Selected paper of OIPE 2016 on modeling and optimal design of electromagnetic and electronic devices

Impacts of ferroresonance and inrush current forces on transformer windings

Deformation of the windings is one of the main causes of the power transformers failure. Here, for the first time, the electromagnetic forces exerted on the windings are computed in ferroresonance condition and compared with that of the inrush current for a typical power transformer. In both cases, the magnetic core of the transformer saturates and the leakage flux around the windings increases, which leads to large forces on the windings carrying high currents. Therefore, precise modelling of the transformer core is required to calculate the forces inside the transformer. For this purpose, the Jiles–Atherton vector hysteresis model is employed in conjunction with finite element method (FEM) to simulate the laminated grain-oriented steel core, and then the radial and axial forces inflicted on the windings are estimated.

A Dynamic Hysteresis Model Based on Vector-Play Model for Iron Loss Calculation Taking the Rotating Magnetic Fields Into Account

This paper presents a simple dynamic vector-play model to calculate the iron loss and describe the vector hysteresis behavior of a non-oriented (NO) electrical steel sheet (ESS) under 50 Hz rotating magnetic fields. Based on the iron loss separation theory, the proposed model is separated to the static hysteresis component and eddy current component. The static hysteresis component is constructed by vector play model, which is identified by using 1 Hz minor $B$ – $H$ loops. And two coefficients $\omega _{x}$ and $\omega _{y}$ are introduced to consider the anisotropic property of NO ESS and the excess loss of eddy-current component under 50 Hz magnetic field. The validity of the proposed dynamic vector hysteresis model is verified by comparing it with the experimental results under various 50 Hz magnetic field conditions.

Computation of Hysteresis Torque and Losses in a Bearingless Synchronous Reluctance Machine

This paper presents the methodology and computation results for the torque and iron losses in a bearingless synchronous reluctance machine. The aim is to compute the hysteresis torque related to the asynchronous operation of the machine under the effect of the levitation field rotating at twice the synchronous speed. For this purpose, and because it is impossible to compute the hysteresis torque with a single-valued B–H characteristic, a magneto-dynamic vector hysteresis model is used. The computations show that the hysteresis-related shaft power is considerable under no-load operation of the machine. It is also shown that the asynchronous torque can be approximated by the classical equivalent circuit of an induction machine.

A Practical Anisotropic Vector Hysteresis Model Based on Play Hysterons

An anisotropic vector hysteresis model based on the improved isotropic vector play operator has been presented to predict the magnetization behavior of anisotropic hysteresis materials. The required parameters can be identified from the major hysteresis loops in all principal axes, which can be easily measured, or are directly available from magnetic material manufacturers. The presented model, which has been successfully implemented in 2-D and 3-D transient finite-element analysis, is validated by numerical experiments and measured data cited from TEAM problem 32, and is applied to simulate a synchronous reluctance motor with an axially laminated anisotropic rotor.

Representation of microstructural features and magnetic anisotropy of electrical steels in an energy-based vector hysteresis model

This paper demonstrates how the statistical distribution of pinning fields in a ferromagnetic material can be identified systematically from standard magnetic measurements, Epstein frame or Single Sheet Tester (SST). The correlation between the pinning field distribution and microstructural parameters of the material is then analyzed.

Pattern search approach to ferromagnetic material modelling

AbstractThis paper deals with possible optimization‐based techniques for the identification of the parameters of Preisach‐inspired phenomenological model of vector hysteresis in ferromagnetic materials. After a summary of the key features of the phenomenological model mentioned above, the description of the identification technique proposed is given. The identification technique is based on a suitable pattern search algorithm and standard measurements. Results for the FeSi Non‐Oriented Grains steel NOG are presented and discussed.

Vector Hysteresis Model Associated to FEM in a Hysteresis Motor Modeling

This paper discusses the implementation of the inverse Jiles-Atherton vector hysteresis model with 2-D finite element (FE) method for the analysis of a hysteresis motor electromechanical behavior. A differential reluctivity tensor couples the hysteresis model with the magnetic vector potential-based FE model. Simulation results are validated by experimental data obtained from a specially designed machine.

An efficient hysteresis modeling methodology and its implementation in field computation applications

Field computation in media exhibiting hysteresis is crucial to a variety of applications such as magnetic recording processes and accurate determination of core losses in power devices. Recently, Hopfield neural networks (HNN) have been successfully configured to construct scalar and vector hysteresis models. This paper presents an efficient hysteresis modeling methodology and its implementation in field computation applications. The methodology is based on the application of the integral equation approach on discretized triangular magnetic sub-regions. Within every triangular sub-region, hysteresis properties are realized using a 3-node HNN. Details of the approach and sample computation results are given in the paper.

A Stable Iteration Procedure of Newton’s Method in Finite-Element Computation of Nonlinear Magnetic Field Problems With a Vector Hysteresis Model

A stable iteration algorithm for solving nonlinear magnetic field problems using the finite-element method (FEM), incorporating a vector Jiles-Atherton hysteresis model and Newton's method, is introduced. The Jacobian matrix is calculated according to the information of the differential reluctivity of the hysteresis loops. In order to balance the FEM computation stability and efficiency, two time criteria are adopted. The proposed FEM procedure is applied to analyze a three-phase transformer made of electrical steel sheets. The numerical computation is stable and fast. The numerically computation results are compared with the experimentally measured ones. The computation efficiency and accuracy proves the effectiveness of the proposed algorithm.

A challenging hysteresis operator for the simulation of Goss-textured magnetic materials

A new hysteresis operator for the simulation of Goss-textured ferromagnets is here defined. The operator is derived from the classic Stoner–Wohlfarth model, where the anisotropy energy is assumed to be cubic instead of uniaxial, in order to reproduce the magnetic behavior of Goss textured ferromagnetic materials, such as grain-oriented Fe–Si alloys, Ni–Fe alloys, and Ni–Co alloys. A vector hysteresis model based on a single hysteresis operator is then implemented and used for the prediction of the rotational magnetizations that have been measured in a sample of grain-oriented electrical steel. This is especially promising for FEM based calculations, where the magnetization state in each point must be recalculated at each time step. Finally, the computed loops, as well as the magnetic losses, are compared to the measured data.

Energy-based ferromagnetic material model with magnetic anisotropy

Non-oriented soft magnetic materials are commonly assumed to be magnetically isotropic. However, due to the rolling process a preferred direction exists along the rolling direction. This uniaxial magnetic anisotropy, and the related magnetostriction effect, are critical to the accurate calculation of iron losses and magnetic forces in rotating electrical machines. This paper proposes an extension of an isotropic energy-based vector hysteresis model to account for these two effects.

Using a Jiles‐Atherton vector hysteresis model for isotropic magnetic materials with the finite element method, Newton‐Raphson method, and relaxation procedure

AbstractThis paper deals with the use of a Jiles‐Atherton vector hysteresis model included in 2D finite element modeling. The hysteresis model is only valid for isotropic materials. It is implemented with the vector potential formulation in 2D along with electric circuit equations to account for a possible external circuit. The Newton‐Raphson algorithm is used with a relaxation procedure, whereby at each iteration, the relaxation coefficient is sought so as to minimize the Euclidean norm of the residual of the finite element nonlinear system of equations. We have simulated several numerical examples with the proposed approach. First, simulations on a square domain were conducted so as to validate the model. We have further simulated a T‐shaped magnetic circuit (exhibiting rotating flux) and a 3‐phase 3‐limb transformer model. For these 2 cases, the eddy current losses in the laminations are taken into account by a low‐frequency model. We have finally performed simulations on the TEAM workshop problem 32, which consists of a 3‐limb transformer with 2 windings, for which current and local magnetic flux density measurements are available. We obtained a good agreement between computed and measured results.

Vector Hysteresis Model Associated With FEM in a Self-Excited Induction Generator Modeling

This paper discusses the implementation of the inverse Jiles–Atherton vector hysteresis model with the 2-D Finite Element Method (FEM) for the analysis of an induction machine operating as self-excited generator. A differential reluctivity tensor couples the hysteresis model with the magnetic vector potential-based finite-element model. Experimental and simulated results (transient and steady state) are presented.

Inclusion of a Direct and Inverse Energy-Consistent Hysteresis Model in Dual Magnetostatic Finite-Element Formulations

This paper deals with the implementation of an energy-consistent ferromagnetic hysteresis model in 2-D finite-element computations. This vector hysteresis model relies on a strong thermodynamic foundation and ensures the closure of minor hysteresis loops. The model accuracy can be increased by controlling the number of intrinsic cell components, while parameters can be easily fitted on common material measurements. Here, the native $h $ -based material model is inverted using the Newton–Raphson method for its inclusion in the magnetic vector potential formulation. Simulations are performed on a 2-D T-shaped magnetic circuit exhibiting rotational flux. By way of validation, the results are compared with those obtained with the dual magnetic scalar potential formulation. A very good agreement for global quantities is observed.

Residual stresses and vector hysteresis modeling

Residual stresses in magnetic materials, whether the result of processing or intentional loading, leave their footprint on macroscopic data, such hysteresis loops and differential permeability measurements. A Preisach-type vector model is used to reproduce the phenomenology observed based on assumptions deduced from the data: internal stresses lead to smaller and misaligned grains, hence increased domain wall pinning and angular dispersion of local easy axes, favouring rotation as a magnetization reversal mechanism; misaligned grains contribute to magnetostatic fields opposing the direction of the applied field. The model is using a vector operator which accounts for both reversible and irreversible processes; the Preisach concept for interactions for the role of stress related demagnetizing fields; and a characteristic probability density function which is constructed as a weighed sum of constituent functions: the material is modeled as consisting of various subsystems, e.g. reversal mechanisms or areas subject to strong/weak long range interactions and each subsystem is represented by a constituent probability density function. Our assumptions are validated since the model reproduces the hysteresis loops and differential permeability curves observed experimentally and calculations involving rotating inputs at various residual stress levels are consistent and in agreement with experimental evidence.

Vector hysteresis model identification for iron–silicon thin films from micromagnetic simulations

In this paper a phenomenological approach, based on a generalization in two dimensions of the classical scalar Preisach model, is exploited and identified to reproduce the magnetization curves obtained by accurate micromagnetic simulations of both isotropic and anisotropic polycrystalline Fe–Si films with different values of the anisotropy constants. The identification problem is realized using a suitable set of analytical equations and performing a best fit procedure to the data obtained from micromagnetic simulations of both scalar and rotational loops. The correct reconstruction of all the magnetization processes, as well as of the associated magnetic losses, is achieved through the choice of a small number of either circular or elliptical hysterons, as well as by the implementation of a simple “moving technique” that is necessary to take into account the non-collinearity between the field and the magnetization that occurs in presence of a global uniaxial anisotropy.