A method to predict AC loss on HTS Coils of a 30-kW generator using the T-A formulation

Abstract

High-temperature superconducting (HTS) conductors are gradually being used in electrical applications and have promising market prospects in the near future. However, HTS conductors inevitably generate AC loss under time-varying currents and magnetic fields. Loss estimation should be of great importance because it influences the generator's structure design and cryocooler's option for HTS applications. In this work, rotating machinery, magnetic (RMM); partial differential equation (PDE); and electrical circuit (CE) modules are fully coupled to calculate the heat dissipation on 30 kW high-temperature superconducting-stator (HTS-stator) coils with the help of Maxwell equations and the T-A formulation. In the whole model, macroscopic results, such as output the voltages and current, are calculated by the RMM and CE modules, while microscopic results, such as the current density distribution and magnetic field penetration, are estimated from the coupling of RMM and PDE modules. It should be noted that an extra deviation value for the current density needs to be introduced into the RMM module for superimposition on the original current density in the HTS coil derived from previous results. By using our model, the AC loss of an HTS coil in this generator is successfully estimated to be 37.3 W. This value is consistent with the result obtained using the magnetic field boundary extraction method. In addition, the AC loss estimation of an HTS coil in the generator is completed under different rotation speeds/frequencies and is positively correlated with them.