Efficient and Practical Models for Numerical Electromagnetic Field Analyses of Three-Dimensional-Shape Coils Wound With Coated Conductor

We have been developing a model for numerical electromagnetic field analyses of three-dimensional-shape coils wound with coated conductor. To analyze three-dimensional-shape coils in a reasonable computation time, we applied thin-strip approximation and other two approximations to our model: a nested-loops approximation and a block approximation. In a nested-loops approximation, each coil turn was approximated as cumulated closed-loops, in a block approximation, several consecutive turns were modeled with an identical current distribution: the bundle of these consecutive turns was called as a block. Analyses were carried out for a single pancake coil to evaluate the errors caused by these approximations. The current profiles as well as temporal evolution of ac losses were compared in various analyses with or without the nested-loops approximation and the block approximation. These approximations were applied to the numerical electromagnetic field analyses of a part of a saddle-shape coil.