Our group has been conducting various studies of high-temperature superconducting induction/synchronous motor (HTS-ISM) for next generation transportation equipment. The HTS-ISM has various advantages, such as co-existence of synchronous and slip rotation modes, high efficiency for variable speed control, high torque density. For the HTS-ISM with copper stator winding, the torque density and efficiency are limited, because of limited current density and large copper losses. In order to achieve higher torque and efficiency, the fully HTS-ISM with superconducting stator winding should be developed.
In this paper, different stator winding structures of a 50kW fully HTS-ISM are studied and compared. Since the distributed winding is difficult to be realized, due to the limitation of bending diameter and mechanical strength of HTS tapes, the conventional concentrated winding and proposed toroidal winding are compared. Firstly, the current transport property of the HTS tape based on the different flux density is measured. Finite Element Analysis (FEA) simulations with different winding structures are performed. The results show the toroidal winding can achieve higher torque and lower torque ripples. Moreover, because of the magnetic mirror image effect, the perpendicular component of flux density HTS tape for toroidal winding is much lower than that of conventional concentrated winding. It demonstrates that the toroidal winding can improve the current transport property of HTS tapes. The detailed results will be shown and discussed.
This work has been supported by Japan Science and Technology Agency under the program of Advanced Low Carbon Technology Research and Development Program (JST-ALCA) in Japan.