Numerical Evaluation of Total AC Loss in Parallel Tape Conductor With Transport Current in Oblique Magnetic Field

We numerically calculate AC losses in a three-strand parallel tape conductor with optimum transposition by means of the finite-element method that directly analyzes the magnetic field distribution. The parallel conductor carries an alternating transport current, whose amplitude is 70% of the critical current, in an in-phase external AC magnetic field that has an arbitrary angle to the flat face of Bi-2223 tapes. It is confirmed that the AC losses in the range of very small and large field amplitude are almost equal to those in cases of applying only a transport current to the parallel conductor and only an external magnetic field to a single Bi-2223 tape, respectively. However it is found that the AC losses are affected by the interaction among the transport current, external magnetic field, and strand number in the range around the full penetration field. Our proposed finite-element analysis helps us to evaluate the AC loss generated in such the middle range of field amplitude quantitatively