Research on magnetic shield effect of AC superconducting armature

The superconducting motor with superconducting armature winding has simple cooling and a high running temperature of 66 K-77 K so the motor with a superconducting armature winding and excitation has been researched by many institutes. When the superconducting armature winding was adopted in the superconducting motors, the magnetic field around the coils would influence its performance. Therefore, this paper researches the distribution of the superconducting coils in the stator tooth-slot environment which is composed of ferromagnetic material. Based on the analysis of electromagnetic distribution, a new shield method is presented for decreasing the magnetic field which is around the superconducting coils when an active current flows through the coils. The shield's ferromagnetic material structure parameters are optimized by FEM (finite element method) software to seek the optimization parameters which create a minimum magnetic field. Finally, the experimental result shows the shield method can decrease the magnetic field around the superconducting coils, and the method can decrease the AC loss of the superconducting coils.