AC Losses in HTS Tapes and Devices With Transport Current Solved Through the Resistivity-Adaption Algorithm

Alternating current (ac) losses in high-temperature superconductor tapes and devices with transport current are solved by using the resistivity-adaption algorithm (RAA). The most advanced feature of the RAA is that it enables the simulation of any model derived from the flux motion theory on finite-element analysis (FEA) packages that have an eddy current solver. The principle of the RAA, as well as its realization on the ANSYS FEA package, is introduced. The simulation begins with the calculation of the ac loss of an ellipse and of strips with aspect ratios ranging from 50 to 2000. The accuracy and efficiency of the calculation are verified through comparisons with the Norris theoretical curves. The possible errors and the method to overcome such errors are discussed. The most significant improvement in the proposed RAA from that discussed in a previous study is that the RAA was proven to be valid for calculating the field-dependent critical state model by using the descendant process from +I_m to -I_m. We then extend this method to calculate the transport ac loss of a stack of ellipses with J_c(B) characteristic from a typical Bi2223/Ag tape and the transport ac loss of a stack of strips with J_c(B) characteristic from a typical YBCO-coated conductor.