In electromagnetic field finite element analysis (FEA)   which is often used in electrical equipment design, there are two iterative processes shown in Fig. 1. The outer loop is nonlinear iteration (Newton-Raphson) for deciding the material property  , and the inner one is solving of linearized equations (ICCG). In these iterative processes, there are issues in which necessary precision cannot be obtained and/or unnecessary processing time is required unless the appropriate determination methods or tolerance values are used. To overcome these challenges, we are taking on various approaches to stabilize iterative processing.
In this report, we will explain the convergence criteria of a local quantity and the improvement of the determination of convergence of ICCG. And then, we describe that these ideas make a good effect to the known problems about the convergence characteristics .