Numerical Solution Of Magnetic Field Research Articles

Investigation of the Magnetic Field Influence of Permanent Adjustable Magnets Matrix on the Whole Positioning Mechanism and Levitating Diamagnetic object

Abstract This article deals with problem solution affecting the magnetic field of permanent magnets by change of their position. This article proves the possibility of magnetic field influence on individual construction parts of a positioning mechanism. The first part of the article deals with the problem of magnetic surface levitation of diamagnetic object and with the description of principle of mechatronic positioning mechanism. Specifically, functions of individual construction parts in term of mechanics are described. Positioning levitating mechanism uses for magnetic field generation the matrix NdFeB 32, which is the matrix of permanent magnets arranged in a particular configuration. Linear actuators working on piezoelectric principle were chosen for magnets positioning. The next part of this article deals with numerical solution of magnetic field using calculation software FEMM, for five different configuration positions of permanent magnets. Using the postprocessor mechanism, outputs, for magnetic induction, for lines of force and for vector fields of each position, are subsequently created. In almost the last part the calculation of energies and forces acting in direction of magnetic field axes X and Y is done. The conclusion involves a summary of the possible influence of magnetic field by the change of magnets position and its subsequent influence on the levitating pyrolitic graphite, which is represented by the diamagnetic object.

Analytical Analysis of Magnetic Field and Back Electromotive Force Calculation of an Axial-Flux Permanent Magnet Synchronous Generator With Coreless Stator

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper presents the analytical analysis of magnetic field and back electromotive force (back EMF) calculation in an axial flux permanent magnet synchronous generator (AFPMSG) without stator core. For the verification, the numerical analysis [finite element method (FEM)] of magnetic field is accomplished and comparison between analytical and numerical solution of magnetic field is presented. Both analytical and numerical solutions are obtained via magnetic vector potential, respectively. This paper also presents the comparison between analytical solution and numerical (FEM) solution of back EMF using Faraday's law. The verifications show that good agreement between analytical and numerical solution of magnetic field and back EMF is obtained. The validity of the proposed analytical method is additionally confirmed with measurements of back EMF on prototype AFPMSG with coreless stator. </para>

A Two-Step Numerical Solution Of Magnetic Field Produced By Elf Sources Within A Steel Pipe - Abstract

-In this paper, we present a two-step numerical technique for the investigation of magnetic fields produced by ELF sources enclosed by a ferromagnetic pipe. The first step is to employ the finite element method to solve the differential equations of the magnetic vector potential, subject to homogeneous Dirichlet boundary condition. The boundary condition is properly set on a circular surface at a distance from the outer surface of the pipe. From the solution of the magnetic vector potential, the electric and magnetic field can be computed. In particular, the fields on the outer surface of the pipe are determined. Then, in the second step, employing the equivalence principle, a computational model equivalent to the region exterior to the pipe is formulated. The equivalent currents can be determined directly from the electric and magnetic field obtained in the first step. Based on knowledge of the equivalent currents, the magnetic field outside the pipe can be computed in a straightforward manner. As an example, the two-step numerical technique is employed to investigate the magnetic field produced by an underground three-phase pipe-type cable. To validate the numerical technique, its numerical results are compared with existing measurement data. A good agreement is observed.

A Two-Step Numerical Solution of Magnetic Field Produced by ELF Sources within a Steel Pipe

Abstract-In this paper, we present a two-step numerical technique for the investigation of magnetic fields produced by ELF sources enclosed by a ferromagnetic pipe. The first step is to employ the finite element method to solve the differential equations of the magnetic vector potential, subject to homogeneous Dirichlet boundary condition. The boundary condition is properly set on a circular surface at a distance from the outer surface of the pipe. From the solution of the magnetic vector potential, the electric and magnetic field can be computed. In particular, the fields on the outer surface of the pipe are determined. Then, in the second step, employing the equivalence principle, a computational model equivalent to the region exterior to the pipe is formulated. The equivalent currents can be determined directly from the electric and magnetic field obtained in the first step. Based on knowledge of the equivalent currents, the magnetic field outside the pipe can be computed in a straightforward manner. A...

Numerical solution of magnetic fields in the vicinity of current-carrying conductors

In most magnetic-field problems of practical interest in machines, transformers and similar devices, the flux distributions required are those in and around current-carrying windings. Here the potential is a vector function, which can be solved by numerical methods only in two dimensions, and which gives poor rates of convergence in regions bounded by iron surfaces of high permeability. The paper describes a scalar-potential method of solving such fields which is not subject to these limitations and which has other advantages. The application of the technique to the calculation of mechanical forces and winding flux linkages is considered.