Adjoint field technique applied in optimal design of a nonlinear inductor

The paper presents an efficient approach based on the adjoint field technique (AFT) for calculating first-order sensitivities of 3D nonlinear magnetic devices to geometric parameters. The sensitivities thus calculated are useful in the devices' (re)design. The design of a nonlinear inductor with imposed flux-current characteristic is formulated as an optimization problem. An algorithm based on geometric sensitivities is used to solve this problem. The general theory and the application presented in the paper prove that AFT is effective not only for linear problems, but for nonlinear ones as well.