Computation of the current density in nonlinear materials subjected to large current pulses
Abstract
The finite element method and the finite difference method are used to calculate the current distribution in two nonlinear conductors. The first conductor is a small ferromagnetic wire subjected to a current pulse that rises to 10,000 Amperes in 10 microseconds. Results from the transient thermal and transient magnetic solvers of the finite element code FLUX2D are used to compute the current density in the wire. The second conductor is a metal oxide varistor. Maxwell's equations, Ohm's law and the varistor relation for the resistivity and the current density of rho = alpha x j(exp beta) are used to derive a nonlinear differential equation. The solutions of the differential equation are obtained by a finite difference approximation and a shooting method. The behavior predicted by these calculations is in agreement with experiments.
 Publication:

Presented at the 4th Biennial IEEE Conference on Electromagnetic Field Computation
 Pub Date:
 1990
 Bibcode:
 1990efc..conf...22H
 Keywords:

 Current Density;
 Current Distribution;
 Electric Pulses;
 Electrical Resistivity;
 Ferromagnetic Materials;
 Pulse Duration;
 Varistors;
 Differential Equations;
 Finite Difference Theory;
 Finite Element Method;
 Magnetic Fields;
 Mathematical Models;
 Maxwell Equation;
 Nonlinear Equations;
 Zinc Oxides;
 Electronics and Electrical Engineering