An Adaptive Newton-Raphson Technique for Combined Vector-Scalar Potential Solutions of Large Scale 3D Magnetic Field Problems Involving Anisotropic Materials

Abstract

In general, magnetic field problems in electrical devices and machines are of nonlinear nature due to magnetic saturation in their ferrous cores. In the combined magnetic vector-magnetic scalar potential (MVP-MSP) method used here, the nonlinearities and anisotropies of the core are handled entirely within the MSP portion of the computation. This is done through the formulation of an adaptive Newton-Raphson (ANR) iterative 3D-finite element (3D-FE) technique, for solution of large scale 3D nonlinear magnetic field problems, which is presented here in this paper. This ANR iterative technique improves and enhances the quality of convergence of the magnetic field solution, as evidenced by a truly 3D magnetic field case-study of a modified Lundell alternator (MLA) performed using CRAY-YMP super computers. Supporting experimental results for verification of the computation are also given in this paper.