Coil Optimization for High Temperature Superconductor Machines

This paper presents topology optimization of HTS racetrack coils for large HTS synchronous machines. The topology optimization is used to acquire optimal coil designs for the excitation system of 3 T HTS machines. Several tapes are evaluated and the optimization results are discussed. The optimization algorithm is formulated to minimize the cost for the coils wound with one type of HTS as well as multiple HTS types. It could also be used to minimize other parameters, e.g. space required for the coils. The results are inherently highly dependent on the HTS properties, which at 20 K seem to be in favor of the 1 G tape. The maximal HTS savings achieved allowing multiple current supplies in the excitation system are investigated and estimated to be in the range of 50% for highly nonlinear J-B dependence HTS tapes.