NEURO-GENETIC OPTIMIZATION OF MAGNETIC HYSTERESIS INTEGRATES IN ELECTROMAGNETIC SYSTEMS

International audienceIn this work we have presented an approach for calculating the hysteresis loop of Jiles-Atherton model using the magnetic inductance as the independent variable is proposed to be used directly in the calculation time step finite volume applied to the numerical analysis of nonlinear magnetic fields. This model is characterized by five parameters that must be identified and optimized for better representation of the measured characteristics. The parameters set of the Jiles–Atherton hysteresis model identified by using a real coded genetic algorithm. The parameters identification performed by minimizing the mean squared error between experimental and simulated magnetic field curves. The method verified by applying it to an axi-symmetrical ferromagnetic system. The calculated results validated by experiences performed in a Single Sheet Tester's frame (SST). In this work, we are interested to develop a model based on feed-forward neural networks of which can describe magnetic hysteresis by taking account the influence of some external sizes

Dynamic Jiles–Atherton Model for Determining the Magnetic Power Loss at High Frequency in Permanent Magnet Machines

This paper describes a mathematical model for the dynamic magnetic power losses in the laminated steel stator of high frequency permanent magnet machines, such as Brushless DC (BLDC) Motors. The model presented is based on a utilization of the dynamic Jiles-Atherton model. Accurate dynamic BH curve fitting and magnetic power loss derivations have been achieved, where the calculated magnetic losses have shown around 95% accuracy from 5 Hz to 2000 Hz, over a flux density range of 1.0 T to 1.6 T. This approach has been applied to estimate the magnetic power loss of a small scale, high frequency (>10,000 rpm) BLDC motor, with calculated and measured losses being in close agreement.This is the author accepted manuscript. The final version is available from IEEE via 10.1109/TMAG.2014.2382594

高クロムフェライト鋼のクリープ劣化の先進的電磁非破壊試験：特性評価、モデリングおよび物理的解釈

Tohoku University内一　哲哉課

Power transformer model in railway applications based on bond graph and parameter identification

Validation and verification are the most important issues in railway applications due to cost and security reasons. Therefore, having a model of the system would be necessary in this case. Due to non-ideal test conditions in industrial applications, an accurate parameter identification process has to be defined. In this paper, bond graph method is used to model energy exchanges within components of a traction chain. More precisely, the non-linear transformer model and its parameter identification is studied. In the case of non-ideal test conditions, the usual Jiles-Atherton parameter identification procedure can not be performed. Regarding state of the art, the Jiles-Atherton parameter identification is discussed. It is highlighted that an uncomplete hysteresis cycle, including extremum point and coercive field are mandatory for an accurate parameter identification. The proposed identification process is applied to a real application case. The obtained parameters are then inserted into the overall system model. The consecutive simulations are compared to experimental data obtained through traction chain test bench

Magneto-Mechanical Model for Hysteresis in Electrical Steel Sheet

A coupled magneto-mechanical model for hysteresis in an electrical steel sheet is presented. The foundation of the model developed is the classical Sablik-Jiles-Atherton (SJA) model. A comprehensive model for the stress dependent magnetostriction is also proposed and implemented in the SJA model. Improvements in the SJA model as well, are proposed and validated with simultaneous measurements of magnetostriction, magnetic field and flux density. The measurements were performed on a single electrical steel sheet under various levels of stress (-35 MPa to 100 MPa). The proposed model was found to adequately model the permeability change and the local bowing of the BH-loop due to stress.Peer reviewe

Modelling of a hysteresis motor using the Jiles-Atherton model

In this paper, we present a model of a hysteresis motor based on Maxwell's equations coupled with the Jiles-Atherton (J-A) hysteresis model solved by the finite element method. The aim of this work is to validate such a model by comparison with the experimental results (electromagnetic torque, voltage, current). We also present an analysis of this motor when imposing current or voltage in the 2D vector potential formulation

Temperature Dependence in the Jiles–Atherton Model for Non-Oriented Electrical Steels: An Engineering Approach

High operating temperatures modify the magnetic behavior of ferromagnetic cores which may affect the performance of electrical machines. Therefore, a temperature-dependent material model is necessary to model the electrical machine behavior more accurately during the design process. Physics-inspired hysteresis models, such as the Jiles–Atherton (JA) model, seem to be promising candidates to incorporate temperature effects and can be embedded in finite element simulations. In this paper, we have identified the JA model parameters from measurements for a temperature range experienced by non oriented electrical steels in electrical machines during their operation. Based on the analysis, a parameter reduction has been performed. The proposed approach simplifies the identification procedures by reducing the number of model parameters and does not require any additional material information, such as the Curie temperature. The resulting temperature-dependent JA model is validated against measurements, and the results are in good agreement

About Mathematical Models of Irreversible Polarization Processes of a Ferroelectric and Ferroelastic Polycrystals

This chapter presents the prevalent mathematical models of irreversible processes in polycrystalline ferroelectric materials when they are subjected to intense electrical and mechanical influences. The main purpose of such models is to describe the dielectric hysteresis loops, with which the models of Rayleigh and Preisach coped well, though they were developed almost a 100 years ago. Nevertheless, in order to describe the whole gamut of material properties in irreversible polarization-depolarization processes, it was required in the last three decades to develop new approaches and methods that take into account the material structure and the physics of the process. In this chapter, we attempted to collect the most common one-dimensional models, with a view to give a brief description of the basics and approaches with the application of working formulas, algorithms and graphs of numerical calculations. On one-dimensional models, the basics of three-dimensional models are worked out, such as evolutionary laws, domains switching criteria, generalizations from “hysteron” to the polarization surface, and so on, so they are a necessary step in modeling. However, some of them proved to be so effective that they obtained the right to independent existence, as happened with the Preisach model, which found application in dynamic systems. This research is based on published articles, monographs, proceedings of conferences, and scientific reports of individual collectives published over the past 20–25 years

Smart switching in single-phase grid-connected photovoltaic power systems for inrush current elimination

Grid-connected photovoltaic (PV) power systems are one of the most promising tech- nologies to address growing energy demand and ecological challenges. This paper proposes smart switching to mitigate inrush currents during the connection of single-phase transformers used in PV systems. An effective inrush current mitigation contributes to the reliability of PV systems. The inrush current severity is influenced by the pseudorandom residual flux at the transformer core and the energization point-on-wave. The most common approach to avoid inrush currents is controlled connection, which requires prior knowledge of the residual flux. However, the residual flux can differ in each case, and its measurement or estimation can be impractical. The proposed smart switching is based on a comprehensive analysis of the residual flux and the de-energization trajectories, and only requires two pieces of data (fRM and f0, flux values of the static and dynamic loops when the respective currents are null), calculated from two simple no-load tests. It has a clear advantage over common approaches: no need to estimate or measure the residual flux before each connection, avoiding the need for expensive equipment or complex setups. Smart switching can be easily im- plemented in practical settings, as it considers different circuit breakers with distinctive aperture features, making it cost-effective for PV systems.Peer ReviewedPostprint (published version