Field and Inductance Calculation of Coaxial Coils with a Hollow Iron Core and a Magnetic Shield

Abstract

An analytical model is developed for coaxial coils with a hollow iron core and a magnetic shield. The problem is solved by an enhanced version of truncated region eigenfunction expansion (TREE). The eigenvalues and eigenfunctions of the complicated mixed regions are solved by the one-dimensional finite element method (FEM). The results are validated by comparisons with measurements and FEM simulation. Additional results reveal that this configuration enables a significant portion of iron core material to be saved while maintaining a high level of magnetic coupling between the coils.

Keywords

• analytical model
• coils
• inductance
• iron core
• truncated region eigenfunction expansion