Evaluation of AC Loss Characteristics of MgB 2 Coil Under Rotating Magnetic Field Generated by PM Rotor

Fully superconducting rotating machines, which have superconducting field and armature windings, attract attention because they achieve high efficiency and high-power density. In the design of a fully superconducting rotating machine, it is very important to estimate the AC losses in the armature windings to which AC magnetic fields and AC currents are applied. Therefore, we measure the AC losses of an armature winding using an AC loss measurement equipment, calculating the AC loss from the difference between the mechanical inputs obtained with and without the superconducting coil present. The rotation of the permanent magnet rotor causes transient phenomena due to the change in magnetic field distribution. In addition, temperature distributions occur along the coil. In this study, we conduct experiments and perform a numerical analysis to evaluate the AC loss characteristics of an MgB2coil under a rotating magnetic field, taking into account the magnetic field distributions. We evaluate the validity of the AC loss measurement using this equipment by comparing the measurement and the numerical analysis results.