New shape of superconducting coil with improved critical current – design and FEM analysis results

Abstract

The novel superconducting HTS coil designed for Superconducting Magnetic Energy Storage (SMES) is the aim of the paper. Novelity lies in the shape of the coil that minimises perpendicular component of the flux density of HTS wire. In this paper authors try to find the shape of the coil where perpendicular component of magnetic field is as close as possible to zero. Proposed solution has the helical shape of coil turns and the special shape of the magnetic core (magnetic core with air gap is needed for increasing stored energy). Helical turns are put on toroidal former and then magnetic core on it. Each turn has the same shape, length and is put in the same magnetic flux. Near-uniform distribution of magnetic flux is the result of the shape of winding and also non-uniform shape (or non-concentric) of magnetic core that has multiple radial air gaps. It produces magnetic field distribution in magnetic core shaped coaxially to winding and distribution of stored magnetic energy uniformly on magnetic core circumference. Magnetic energy is stored in air gaps and proposed shape of core is the best solution of core but its fabrication produces technological difficulties in core manufacturing.