Inductance calculations for coaxial iron-core coils shielded by cylindrical screens of high permeability

摘要

Coaxial iron-core coil system shielded by a magnetic screen is a complex model for analytical calculation, because a complicated boundary value problem must be tackled for obtaining inductances of the coils in this situation. Truncated region eigenfunction expansion method is a suitable way to work out such a problem containing complex boundary conditions. Three different models are taken into consideration in this study. Starting with coil system shielded by two infinitely large plates, the basic steps of the proposed method are introduced carefully. Then the relevant techniques and conclusions are applied to the iron-core coils shielded by a fully enclosed cylindrical screen of high permeability and a lidless one. The effectiveness of the proposed method is verified by comparing with finite element method software and experiments. From relevant data, it is evident that the proposed method is much faster and can be easily used for forecast and evaluation of new schemes in device design process.