Presentation Information
[APP2-09]Experimental AC loss study on REBCOcoil assemblies coupled with an ironcylinder
*Zhenan Jiang1, Yue Wu1,2, Jin Fang2, Daisuke Miyagi3, Naoyuki Amemiya4, Rodney A. Badcock1, Nicholas J. Long1 (1. Robinson Research Institute, Victoria University of Wellington (New Zealand), 2. School of Electrical Engineering, Beijing Jiaotong University (China), 3. Department of Electrical and Electronic Engineering, Chiba University (Japan), 4. Graduate School of Engineering, Kyoto University (Japan))
Keywords:
Transport AC loss,REBCO coil assemblies,Iron core,Superconducting coils,FEM
In high-temperature superconducting (HTS) power devices, the presence of iron cores changesthe magnetic field profile around the HTS coil windings, potentially affecting their AC losscharacteristics. AC loss measurements for HTS coil windings coupled with an iron core usingthe electrical method can lead to a significant error, owing to the indirect estimation of the ironcore loss through using a copper test coil.
To investigate the cause of the experimental error andthe influence of an iron core on coil AC losses, transport AC losses of REBCO double pancakecoil (DPC) assemblies coupled with an iron cylinder were measured. A 40-turn 1DPC and an80-turn 2DPC assembly wound with 4 mm SuperPower wire were employed in themeasurements. To ensure the same iron core loss using the HTS coil assembly and the coppercoil, 2D finite element method simulations were conducted iteratively to design the iron coreand the copper coil to get the same local magnetic field distributions in the designed iron corefor the two cases.
The main cause of the error is due to the difference in local magnetic fluxdensities in the iron core generated by the HTS coil assembly and the copper coil even when theampere-turns of the coils are identical. We showed that the simulation-guided measurementmethod can assure accurate AC loss measurement in the HTS coil assemblies coupled with ironcores. Compared with the AC losses in the 1DPC and 2DPC coil assemblies without the ironcylinder, the presence of the iron cylinder significantly increases the coil losses. Frequencydependence is observed in the coil AC losses of the 1DPC and 2DPC assemblies when coupledwith the iron cylinder. This is due to the eddy current induced in the iron cylinder generating amagnetic field, which influences the coil AC loss.
To investigate the cause of the experimental error andthe influence of an iron core on coil AC losses, transport AC losses of REBCO double pancakecoil (DPC) assemblies coupled with an iron cylinder were measured. A 40-turn 1DPC and an80-turn 2DPC assembly wound with 4 mm SuperPower wire were employed in themeasurements. To ensure the same iron core loss using the HTS coil assembly and the coppercoil, 2D finite element method simulations were conducted iteratively to design the iron coreand the copper coil to get the same local magnetic field distributions in the designed iron corefor the two cases.
The main cause of the error is due to the difference in local magnetic fluxdensities in the iron core generated by the HTS coil assembly and the copper coil even when theampere-turns of the coils are identical. We showed that the simulation-guided measurementmethod can assure accurate AC loss measurement in the HTS coil assemblies coupled with ironcores. Compared with the AC losses in the 1DPC and 2DPC coil assemblies without the ironcylinder, the presence of the iron cylinder significantly increases the coil losses. Frequencydependence is observed in the coil AC losses of the 1DPC and 2DPC assemblies when coupledwith the iron cylinder. This is due to the eddy current induced in the iron cylinder generating amagnetic field, which influences the coil AC loss.