Acceleration of Transient Non-Linear Electromagnetic Field Analyses Using an Automated Subspace Correction Method

In this paper, we propose a mapping operator generation method for the subspace correction to accelerate transient and/or nonlinear eddy-current analyses. In these analyses, a sequence of linear systems whose coefficient matrices are similar or identical is solved. In our method, we automatically construct the operator using the information obtained in the preceding solution steps. The operator is generated with minimum additional memory requirement through the sampling of approximate solution vectors and the use of the Rayleigh-Ritz's method. Numerical tests using transformer and box-shield models demonstrate that the subspace correction based on the proposed method significantly reduces the number of iterations and the computational time.