Inductance computation by incremental finite element analysis

The paper introduces the enhanced incremental energy method (EIEM) for the accurate and efficient computation of nonlinear differential inductance coefficients. The EIEM has the following advantages: (i) only one incremental analysis is required for any coefficient, self or mutual; (ii) first derivative evaluation; (iii) the current increment may be large; (iv) there is no need to evaluate the nonlinear magnetic energy, instead, an "incremental energy" is calculated according to a simple expression; (v) only load vectors should be computed, the stiffness matrix can be saved; (vi) if a direct solver is applied, additional matrix factorization is avoided. These advantages provide improved accuracy and computational efficiency. The paper outlines the new EIEM and illustrates it the example of a transformer.