Numerical Study on AC Loss of an HTS Coil Placed on Laminated Silicon Steel Sheets With Distorted AC Transport Currents

Xu, Xiaoyong; Huang, Zhen; Huang, Xiangyu; Hao, Luning; Zhu, Jiamin; Shen, Boyang; Li, Wan; Jiang, Junjie; Wang, Mingyang; Jin, Zhijian

doi:10.1109/tasc.2020.2974840

Cited by 7 publications

(7 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…the total AC loss was reduced by 80%. Such a significant AC loss reduction in REBCO coil windings using MFDs has not been reported in previous experimental works [42]- [51], [52]. The measurements at the other two frequencies show almost the same results.…”

Section: Resultssupporting

confidence: 63%

“…In addition to fabricating the REBCO wires themselves, applying magnetic flux diverters (hereinafter referred to as MFDs) in the coil design is another effective approach to reduce AC loss [42]- [51], [52]. This is because MFDs can reshape the distribution and reduce the radial component of magnetic fields in the REBCO coils.…”

Section: Magnetic Flux Divertersmentioning

confidence: 99%

“…An effective method to reduce AC loss is applying magnetic flux diverters (hereinafter referred to as MFDs) to HTS coil windings [42]- [51], [184]. MFDs can reshape the distribution of magnetic flux lines in the coil windings hence can reduce AC loss caused by the perpendicular magnetic field to the superconductor surface [185], [186].…”

Section: Chapter 4 Ac Loss Reduction In An Hts Coil Assembly By Apply...mentioning

confidence: 99%

“…Moreover, on the coil level, using MFDs (magnetic flux diverters) is an efficient method to reduce the AC loss [42]- [51]. The AC loss in an HTS coil is mainly caused by the radial component of magnetic fields, which is perpendicular to the wide-surface of HTS tapes.…”

mentioning

confidence: 99%

See 3 more Smart Citations

AC Loss Reduction in HTS Coils and Armature Windings of Fully Superconducting Motors

You¹

View full text Add to dashboard Cite

High AC loss in armature windings is one of the greatest barriers to achieve practical fully-HTS (high-temperature superconducting) motors. At present, AC loss estimation for HTS armature windings is one of the core technical challenges. AC loss behaviours and AC loss reduction methodologies have not been fully investigated in REBCO (REBa2Cu3O7-x, RE: rare earth) HTS armature windings carrying AC current under rotating magnetic fields. Many open questions need to be studied, of which this thesis addresses the three most prominent: can significant AC loss reduction be achieved by using low-loss MFDs (magnetic flux diverters); is it feasible to apply MFD structure to the HTS armature windings; and what kind of REBCO conductor types for armature windings generate less AC loss. The goal of this thesis is applying experimental and numerical methods to investigate AC loss behaviours and AC loss reduction methodologies in the HTS windings wound with REBCO wires. Specifically, it includes investigating AC loss reduction in HTS coil assembly by using low-loss MFDs; building numerical models for fully-HTS motors; and developing methodologies to achieve AC loss reduction in the HTS armature windings. We firstly explored the effectiveness of AC loss reduction on a REBCO four double-pancake coil assembly by using low-loss MFDs, MPP (Molypermalloy powder) MFDs and HF (High flux) MFDs. These have not been studied with HTS coils before. The measured and simulated results show that both MFDs can significantly reduce the total loss (the summation of the losses in the HTS windings and MFDs) in the system. At 77 K and 40 A coil current, compared with the coil assembly without MFDs, the total loss with HF and MPP MFDs is reduced by 77% and 81%, respectively. Although MPP MFDs show slightly better performance in reducing total loss at low coil current, HF MFDs are the more obvious option for AC loss reduction in high magnetic field applications owing to their relatively high saturation field. Next, we developed numerical models to investigate the AC loss reduction in the armature windings of a 50 kW fully HTS motor by applying pole shoes, which function as MFDs. For comparison, two motor designs with and without pole shoes have been considered in the finite-element method (FEM) models. REBCO coated conductors were considered for both the armature and field windings, and 2D FEM models of both designs were built using the T-A formulation (T: current vector potential, A: magnetic vector potential) and rotating meshes. The simulation results show that flux diverting pole shoes reduced the perpendicular magnetic field in the armature windings and provided a 51% AC loss reduction, without weight penalty or motor power rating reduction. Finally, AC loss simulation in HTS armature windings of a 100 kW HTS motor wound with different types of REBCO conductor arrangements were carried out. Three types of conductors, 4 mm-wide REBCO conductors, 14/2 (14 strands, each strand is 2 mm wide) REBCO Roebel cables and striated REBCO conductors with four 1 mm-wide filaments, were considered in the armature windings. The simulation results show that both Roebel cables or striated conductors can significantly reduce the AC loss in the armature windings compared with 4 mm-wide conductors. Further, a 2% AC loss reduction can be achieved in the armature winding wound with REBCO conductors with asymmetric Ic(B, θ) characteristics by simply flipping the direction of the conductors. This work provides a method to achieve large AC loss reduction in HTS coil windings by using low-loss MFDs. Also, it supplies practical implications for designing armature windings of fully-HTS superconducting rotating machines. The methodologies of AC loss reduction in this thesis also can be applied to other HTS applications, such as transformers, and fast ramping magnets.

show abstract

Section: Resultssupporting

confidence: 63%

Section: Magnetic Flux Divertersmentioning

confidence: 99%

Section: Chapter 4 Ac Loss Reduction In An Hts Coil Assembly By Apply...mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

AC Loss Reduction in HTS Coils and Armature Windings of Fully Superconducting Motors

You¹

View full text Add to dashboard Cite

show abstract

“…Several numerical and experimental studies on the influence of ferromagnetic materials in AC loss of HTS tapes, stacks, and coil windings have been conducted [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]. Previous numerical works based on the finite element method (FEM) have shown that iron cores influence the AC loss of HTS coil assemblies [26][27][28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Experimental AC loss study on REBCO coil assemblies coupled with an iron cylinder

Wu,

Fang,

Miyagi

et al. 2024

Supercond. Sci. Technol.

View full text Add to dashboard Cite

In HTS power devices, the presence of iron cores changes the magnetic field profile around the HTS coil windings, potentially affecting their AC loss characteristics. AC loss measurements for HTS coil windings coupled with an iron core using the electrical method can lead to a significant error, owing to the indirect estimation of the iron core loss through using a copper test coil. To investigate the cause of the experimental error and the influence of an iron core on coil AC losses, transport AC losses of REBCO double pancake coil (DPC) assemblies coupled with an iron cylinder were measured. A 40-turn 1DPC and an 80-turn 2DPC assembly wound with 4 mm SuperPower wire were employed in the measurements. To ensure the same iron core loss using the HTS coil assembly and the copper coil, 2D finite element method (FEM) simulations were conducted iteratively to design the iron core and the copper coil to get the same local magnetic field distributions in the designed iron core for the two cases. The main cause of the error is due to the difference in local magnetic flux densities in the iron core generated by the HTS coil assembly and the copper coil even when the ampere-turns of the coils are identical. We showed that the simulation-guided measurement method can assure accurate AC loss measurement in the HTS coil assemblies coupled with iron cores. Compared with the AC losses in the 1DPC and 2DPC coil assemblies without the iron cylinder, the presence of the iron cylinder significantly increases the coil losses. Frequency dependence is observed in the coil AC losses of the 1DPC and 2DPC assemblies when coupled with the iron cylinder. This is due to the eddy current induced in the iron cylinder generating a magnetic field, which influences the coil AC loss.

show abstract

Quantitative evaluation of DC voltage–current characteristics of a high temperature superconducting stator winding located in silicon steel core at 77 K

Ikeda

Nakamura

Yoshikawa³

et al. 2021

Cryogenics

View full text Add to dashboard Cite

Numerical Study on AC Loss of an HTS Coil Placed on Laminated Silicon Steel Sheets With Distorted AC Transport Currents

Cited by 7 publications

References 16 publications

AC Loss Reduction in HTS Coils and Armature Windings of Fully Superconducting Motors

AC Loss Reduction in HTS Coils and Armature Windings of Fully Superconducting Motors

Experimental AC loss study on REBCO coil assemblies coupled with an iron cylinder

Quantitative evaluation of DC voltage–current characteristics of a high temperature superconducting stator winding located in silicon steel core at 77 K

Contact Info

Product

Resources

About