Solving 1D non-linear magneto quasi-static Maxwell's equations using neural networks

Electromagnetics (EM) can be described, together with the constitutive laws, by four PDEs, called Maxwell's equations. “Quasi-static” approximations emerge from neglecting particular couplings of electric and magnetic field related quantities. In case of slowly time varying fields, if inductive and resistive effects have to be considered, whereas capacitive effects can be neglected, the magneto quasi-static (MQS) approximation applies. The solution of the MQS Maxwell's equations, traditionally obtained with finite differences and elements methods, is crucial in modelling EM devices. In this paper, the applicability of an unsupervised deep learning model is studied in order to solve MQS Maxwell's equations, in both frequency and time domain. In this framework, a straightforward way to model hysteretic and anhysteretic non-linearity is shown. The introduced technique is used for the field analysis in the place of the classical finite elements in two applications: on the one hand, the B–H curve inverse determination of AISI 4140, on the other, the simulation of an induction heating process. Finally, since many of the commercial FEM packages do not allow modelling hysteresis, it is shown how the present approach could be further adopted for the inverse magnetic properties identification of new magnetic flux concentrators for induction applications

Application of Rechargeable Batteries of Electrical Vehicles as Time Dependent Storage Resource for the Public Electricity Grid

This study investigates the potential to use the EES storages of a fleet of privately owned Electrical Vehicles (EV) as time dependent storage source connected to the electrical grid. The example of the national German electricity grid is examined. Calculations are done as time series on a complete yearly set of quarter-hour data for generation and consumption, as obtained from the national regulatory authority (“Bundesnetzagentur”). Future scenarios foresee targets that have been publicly stated by the German government, e.g. the projected discontinuation of electricity generation by nuclear power, the envisaged shares of renewables within the electricity mix per 2030 or 2050, and a projected evolution of the number of EV. Besides, the technical evolution like introduction of new types of EES like the Li-Air-storage promising higher storage capacity in the future is expected. The model assumes that private users of EV will provide the storage capacity within their EV to the public grid following a certain time pattern. A minimum reserve for the user is always granted and moreover it is assumed that the electrical system operator will make compensation payments to the user of the EV. In a scenario beyond 2030 where 6 Mio EV are projected, the number of EV is assumed to be 20 Mio EV in 2050. This results in a considerably large distributed storage to help dealing with a future more and more volatile electricity provision by more and more renewable energy sources, especially wind and PV. According to our preliminary results, an optimum for this model can be obtained at moderate power levels for charge and discharge, avoiding the necessity for a comparable high invest of “fast charging” stations

Coupled numerical multiphysics simulation methods in induction surface hardening

Numerical simulation is a valuable tool to help investigate complex multiphysics problems of engineering and science. This also applies to inductive surface hardening with its coupled electromagnetic and temperature fields as well as the microstructure changes of the hardened material. In this field, numerical simulation is a well-established approach for effective process design. This is particularly true since an analytical approach usually fails because of the complexity of the problems. Also, experiments oftentimes are not leading to a solution in an acceptable period of time because of the big number of process parameters. Furthermore, numerical simulation can help to investigate effects that could not have been observed otherwise. An example is the Joule heat distribution within a heated work piece during inductive heating. However, the fields of application as well as the methods of numerical simulation have to keep pace with technological progress. Two examples of new applications and methods for numerical simulation in induction hardening are presented in this paper: A complex 3D model of a large bearing and a new approach for the numerical simulation of the martensite microstructure

FERROELECTRIC NANOCOMPOSITES WITH GOVERNED INTERFACE ON BASE OF MAGNETIC POROUS GLASSES

Two-phase (nonporous) magnetic alkali borosilicate glasses have been produced by induction melting. Their macroscopic properties and crystal structure have been studied and it is shown that in the silica skeleton there are the agglomerates of Fe3O4. These agglomerates are formed by monodomain nanoparticles of magnetite and demonstrate the superparamagnetic properties. After special thermal treatment (liquation process) and chemical etching the nanoporous matrices with random dendrite pore structure and magnetic properties have been produced. The channels (porous space) were filled by ferroelectric materials KH2PO4 (KDP), KH2PO4+(NH4)H2PO4 (KDP-ADP or KADP), and NaNO2 and the effect of applied magnetic fields on phase transitions in these nanocomposite have been studied. It has also been established that a restricted geometry changed essentially the phase diagram of KADP.

Numerical simulation and investigation of induction through-heaters in dynamic operation mode

Purpose - Because of their widespread use in industry, induction through-heaters of various metal products must be of high effectiveness not only in "quasi" steady-state operation but in different transient modes as well. Nowadays, they are usually designed to provide the required characteristics in "quasi" steady-state operation mode mainly. The purpose of this paper is to examine numerical simulation of transient processes in induction through-heating lines generally and investigate dynamic temperature fields during the first start of the heaters particularly. Design/methodology/ approach - The research methodology is based on coupled numerical electromagnetic and thermal analyses using FEM approach. ANSYS simulations are supported with the developed tools for imitation of mass transfer effects in continuous induction heating lines. Findings - The results show that transient temperature fields in the heated strip or slab significantly differ from their "quasi" steady-state descriptions. Local temperature variations acquired in longitudinal as well as transverse flux induction heaters during the first start have been predicted. Practical implications - The received results can be used for design of induction through-heaters and improvement of their characteristics in dynamic operation modes. Originality/value - Investigation of dynamic characteristics of the heaters in dynamic modes can be only done by numerical modelling based on special algorithms providing a time loop additional to coupling between electromagnetic and thermal analyses. Such algorithms have been developed and used for investigation of two types of induction installations: through-heaters of cylindrical billets for forging and heating lines of strip or thin slab for rolling mills. © 2011 Emerald Group Publishing Limited. All rights reserved

SEM and AFM studies of two-phase magnetic alkali borosilicate glasses

The morphology and composition of four types of two-phase alkali borosilicate glasses with magnetic atoms prepared by inductive melting have been studied. The results of scanning electron microscopy point to uniform distribution of Na, Si, and O atoms in these samples whilemagnetic iron atoms formball-shaped agglomerates. The magnetic properties of these agglomerates have been confirmed by magnetic force microscopy. Atomic force microscopy had shown that in these samples two different morphological structures, drop-like and dendrite net, are formed. The formation of dendrite-like structure is a necessary condition for production of porous magnetic glasses. The obtained results allowus to optimize the melting and heat treatment processes leading to production of porous alkali borosilicate glasses withmagnetic properties. The first results for nanocompositematerials on the basis ofmagnetic glasses containing the embedded ferroelectrics KH2PO4 demonstrate the effect of applied magnetic field on the ferroelectric phase transition. The morphology and composition of four types of two-phase alkali borosilicate glasses with magnetic atoms prepared by inductive melting have been studied. The results of scanning electron microscopy point to uniform distribution of Na, Si, and O atoms in these samples whilemagnetic iron atoms formball-shaped agglomerates. The magnetic properties of these agglomerates have been confirmed by magnetic force microscopy. Atomic force microscopy had shown that in these samples two different morphological structures, drop-like and dendrite net, are formed. The formation of dendrite-like structure is a necessary condition for production of porous magnetic glasses. The obtained results allowus to optimize the melting and heat treatment processes leading to production of porous alkali borosilicate glasses withmagnetic properties. The first results for nanocompositematerials on the basis ofmagnetic glasses containing the embedded ferroelectrics KH2PO4 demonstrate the effect of applied magnetic field on the ferroelectric phase transition.DAA