Recent Developments in 2G HTS Coil Technology

Transcription

1 superior performance. powerful technology. Recent Developments in 2G HTS Coil Technology Drew W Hazelton Principal Engineer SuperPower Inc Applied Superconductivity Conference August 1-6, 2010 Washington, DC SuperPower, Inc. is a subsidiary of Royal Philips Electronics N.V.

2 SuperPower Focus: 2G HTS Wire, Coils Development and manufacture of secondgeneration (2G) high-temperature superconductor (HTS) WIRE Suitable for a wide variety of applications: research, energy, military, defense, industrial, transportation, high energy physics, medical, space Design and fabrication of COILS based on 2G HTS wire Engineering services 2

3 SuperPower 2G HTS Wire Substrate Electropolishing Superconductor: Uniform thickness Silver Sputtering Substrate: Smooth and Clean Buffer: Good Texture Buffer IBAD Copper Electroplating HTS MOCVD Superconductor: Composition 3

4 Modeling 2G HTS Conductor Performance 2G HTS conductor critical current vs. temperature, magnetic field, magnetic field angle and composition ac losses quench initiation and propagation mechanical performance fault current limiting performance Quench Dynamic resistance Thermal modeling temperature rise, conductor re-cool 4

5 SP 2G HTS has excellent performance over a wide field and temperature range I c /I c (77K, 0T) vs. Field (perpendicular) K (Sample 1) 14 K (Sample 1) 22 K (Sample 1) 33 K (Sample 1) 45 K (Sample 2) 50 K (Sample 2) 65 K (Sample 2) 77 K (Sample 2) Ic (H//c)/Ic (77K 0T) H (T) 5

6 2G HTS in-field performance modified with advanced pinning In field performance vs. field angle drives coil design and performance Critical region for coils is often degrees Significant drop-off in Ic Relatively large field component New wire with advanced pinning becoming available Critical current (A/cm-width) micron SmYBCO micron GdYBCO micron Zr:GdYBCO K, 1T Angle (degree) 6

7 Modeling of wire Ic vs. operating parameters for coil performance evaluation Θ (deg) I c (A) Low Field c a b Medium Field High Field HTS coil performance is often determined by anisotropy in field dependence High flux density at small angles (Near B//ab) Medium flux density at intermediate angle (20-30 deg) Low flux density at high angle (B//c) 7

8 Universal Jc/Jco vs. H/Hirr curves can be developed H // c (undoped) Universal Curve for 2G Conductor, H//c Temp (data set) 83K (8) 82K (1) 77K (1) 77K (4) 77K (5) 77K (7) 77K (9) 75K (6) 72K (1) 65K (1) 65K (9) 60K (8) 54K (8) 50K (1) 50K (2) 50K (4) 50K (7) 50K (9) 45K (1) 45K (9) 42K (8) 40K (2) 33K (9) 30K (2) 30K (4) 22K (9) 20K (2) 20K (7) 15K (2) 14K (9) 10K (2) 10K (7) 4.2K (3) 4.2K (6) 4.2K (9) Jc / Jco Data Set 1: NHMFL PB Data Set 2: NHMFL PB Data Set 3: NHMFL PB Data Set 4: NHMFL PB C Data Set 5: NHMFL 1217 Data Set 6: PLee/LANL 1996 data Data Set 7: PB Jc(θ) min Data Set 8: ONRL meas "std" cond Data Set 9: SP release 11/ H / H irr 8

9 Similar data H//a,b (undoped) Universal Curve for 2G Conductor, H//a,b K (8) 77K (7) 75K (6) 60K (8) 54K (8) 50K (7) 42K (8) 20K (7) 10K (7) 4.2K (3) Jc / Jco Data Set 3: NHMFL PB Data Set 6: PLee/LANL 1996 data Data Set 7: PB Jc(θ) max Data Set 8: ONRL meas "std" cond H / H irr 9

10 H irr from normal state phase diagram Superconducting - normal state phase diagram Hirr // c Hirr // ab Poly. (Hirr // ab) Poly. (Hirr // c) Hirr // c = E-02x E+00x E+02 R 2 = E-01 Hirr // ab = E-01x E+01x E+03 R 2 = E H irr //c (Tesla) H irr /ab (Tesla) Temperature (K) 10

11 J co measured from sample materials (undoped) Jco vs. Temp y = E-05x E-03x E-01x E+01 R 2 = E Jco (MA/cm2) Jco Poly. (Jco) Temp (K) 11

12 Three distinct regions exist on universal curve Universal Curve for 2G Conductor, H//c Jc/Jco constant (low fields) Temp (data set) 83K (8) 82K (1) 77K (1) 77K (4) 77K (5) 77K (7) 77K (9) 75K (6) 72K (1) 65K (1) 65K (9) 60K (8) 54K (8) 50K (1) 50K (2) 50K (4) 50K (7) 50K (9) 45K (1) 45K (9) 42K (8) 40K (2) 33K (9) 30K (2) 30K (4) 22K (9) 20K (2) 20K (7) 15K (2) 14K (9) 10K (2) 10K (7) 4.2K (3) 4.2K (6) 4.2K (9) Power Law region (intermediate fields) Kramer Law region (high fields) Jc / Jco Data Set 1: NHMFL PB Data Set 2: NHMFL PB Data Set 3: NHMFL PB Data Set 4: NHMFL PB C Data Set 5: NHMFL 1217 Data Set 6: PLee/LANL 1996 data Data Set 7: PB Jc(θ) min Data Set 8: ONRL meas "std" cond Data Set 9: SP release 11/ H / H irr 12

13 Power Law Region Power Law Fit - Combined Data H//c 10 y = x R 2 = Jc / Jco H / Hirr 13

14 Kramer Law Region Modified Kramer Plot, H//c 83K (8) 82K (1) 77K (1) 77K (4) 77K (5) 77K (7) 77K (9) 75K (6) 72K (1) 65K (1) 65K (9) 50K (7) 50K (9) combined Linear (combined) y = x R 2 = (Jc/Jco) 0.5 (H/Hirr) H / H irr 14

15 Model values match measured values well Refined model check Ic(B,T) / Ic(sf,77K) K Refined 4.2K Data 14K Refined 14K Data 22K Refined 22K Data 33K Refined 33k Data 45K Refined 45K Data 50K Refined 50K Data 65K Refined 656k Data 77K Refined 77k Data Applied Field, B//c (T) 15

16 Peak width shows anomaly? at higher temperatures Peak Width at Δ/2 (deg) y = x R 2 = H / H irr // ab 77K 77K 77K 77K 77K 77K early 75K 75K early 65K 50K 20K 10K summary Power (10K) Power (20K) Power (50K) Power (65K) Power (77K) Power (75K early) Power (summary) 16

17 Model gives design data that can be applied to any point in the 2G windings Top = K 20 Ic(Bφ,T) / Ic(sf, 77K) Ic //a,b Ic // c Peak width Ic(B,T) / Ic(sf,77K) field angle φ (deg) 17

18 Internal codes (MagMan) give field strength vs. location in magnet windings(discrete points) Coil H2 - Total Field total field (gauss) axial position (cm) radial position (cm) 18

19 Internal codes also give field angle information Coil H2 - Field Angle From +Z Axis field angle (deg) radial position (cm) axial position (cm) 19

20 Semi-empirical model developed to predict conductor performance under varied operating conditions Ideally, this type of data is desirable for each location within a coil winding Ic //a,b Ic // c Peak width Ic(B,T) / Ic(sf,77K) Top = K 20 Ic(Bφ,T) / Ic(sf, 77K) field angle φ (deg) 20

21 Evaluating each point using model values gives Iop/Ic value Coil H2 - Iop / Ic Plot Ic (77, sf) = 80 A, Iop = 60 A, Top = 50 K Iop / Ic For each point, we know field strength, field angle and Ic allows us to determine Iop/Ic radial position (cm) axial position (cm)

22 Results can be used to look at coil heating, quench initiation Coil H2 - Iop / Ic Plot Ic (77, sf) = 80 A, Iop = 60 A, Top = 60 K Iop / Ic axial position (cm) radial position (cm) 22

23 Further steps Further refinement of Ic vs. field angle model Need to update model for advancements in pinning Power law exponent changes Peak width broadening with second phase dopants Introduction of minor Ic // c peak Further refinement of thermal model using generated data 23

24 Other modeling efforts 2G HTS wire critical current vs. temperature, magnetic field, magnetic field angle and composition impact of dopants ac losses quench initiation and propagation mechanical performance fault current limiting performance Quench Dynamic resistance Thermal modeling temperature rise, conductor re-cool Impact of parallel shunt element on performance 24

25 Modeling of impact of nano-defect sources for bidirectional pinning at different temperatures and fields HREM of nanocluster HREM of nanorod Horizontal (Gd,Y) 2 O 3 nano cluster Vertical BZO Nanorod TEM by F. Kametani (TEM) and D. Larbalestier, FSU 25

26 Multfilamentary 2G HTS tapes for low ac loss applications being developed Filamentization of 2G HTS tapes is desired for low ac loss applications. Refined modeling of ac loss reduction required ac loss (W/m) Hz B ac rms (T) unstriated 5.1 x multifilamentary 4 mm 5-filament tape, 4 mm wide 32-filament tape, 4 mm wide 26

27 Stress modeling in mechanically anisotropic coil structures Coil 1 Stress Distribution Stress (MPa) σ θ (adjacent turn) σ θ (independent turn) σr (adjacent turn) Normalized Radius ε 2G HTS coil generates 27T in 20 T background 27

28 Modeling of 2G wire for SFCL High-power SFCL test Prospective current Limited current Peak current through element Response time Element quality range Fast response time 2G 90 ka* 32 ka 3 ka < 1 ms Narrow Quench Dynamic resistance Thermal modeling of temperature rise, conductor re-cool Impact of parallel shunt element on performance Current [ka] Current [ka] Time [ms] Voltage across HTS elements [kv] Iprospective I_total_KEMA I_HTS Ish V_total_KEMA Quench speed around 0.5 ms Time [ms] I_total_KEMA I_HTS Ish V_total_KEMA Voltage across HTS elements [kv] 28

29 Summary Many aspects of the 2G HTS conductors need to be modeled Models will need to be upgraded as conductor improvements are implemented Different architectures Composition changes in the HTS layer impacting Ic performance characteristics In addition to conductor based models, application specific evaluations will need to be conducted Quench Heat transfer within device and transfer to coolant Mechanical 29

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