Towards compact and lightweight Electrical Machines

Towards compact and lightweight Electrical Machines

Department of Superconducting Materials and Large Scale Nanoestructures

State Agency Spanish Highest Council of Scientific Research, CSICInstitute of Materials Science of Barcelona, ICMAB‐CSIC

X. Granados, T. Puig and X. Obradors, g

SUNJET UE‐Japan Symposium “Electrical T h l i f th i ti f th f t ”Technologies for the aviation of the future”March 26‐27 2015, Tokyo

“Electrical Technologies for the aviation of the future”, X. Granados , T. Puig, X. Obradors, 26‐27/03/2015, Tokyo

Where are we?


Where are we?

SUMAN Group 20 researchers7 permanent7 permanent

Main activity: functional materials

Staff: 200 peopleStaff: 200 peopleAbout 50 permanents


Applications and material development


Applications and material development


Applications development

International cofundedprojects in HTS EngineeringFlywheel (Brite Euram)

Activities on HTS Engineering

Motors Supermachines (TMR FP5)Inductively coupled fault Limiters (ByFault, Brite Euram)Cable HTS Super 3C (FP6)Superconductivity in space propulsion (ESA)Superconductivity in space propulsion (ESA)Current limiter resistive ECCOFLOW (FP7)High Performance Computation for HTS FORTISSIMO (FP7)Assessment of HTS tapes for fusion (EFDA WS 2) Assessment of HTS tapes for fusion (WP MAG EUROFUSION)Hybrid Energy storage (COST Action MP1004)

National funded Projects in HTS EngineeringNational funded Projects in HTS EngineeringCurrent Leads (Midas Project)Superconducting motor(PETRI)Superconducting motor(Feder)Levitation system(Fundació laCaixa)HTS Cable “Supercable” (Novare Endesa)Superconducting Magnet for ALBA Synchrotron (Grandes Instalaciones)Generator(CENIT AZIMUT 10 MW and beyond)Generator(CENIT AZIMUT 10 MW and beyond)Generator (Retos Colaboración, new Wind technologies)


Electrical evolution in aircraft‐tech

T di it f l t i l MW h ld b h dl dTwo digits of electrical MW should be handled


Why Superconductivity can help?

N i t

M

No resistanceDiamagnetismMagnetic Flux trapping

Macrosc

Electro‐technicalApplications

Magnetic Flux trappingCurrent Driven Transition

copicM Sensors (SQUID)Microsc

Electronic interactions. Vortex dynamics & other

Sensors (SQUID)

Superconductingelectronic Devicescopic

Micro‐nanoscopic & quanticeffects

electronic Devices

MicrowavesETC.


Existing HTS Materials: Bulks & wires

Powder in tubeBulk

MgB2

TAPES

Bi‐2212Bi‐2223 Tape

1G

TAPES

Bi‐2212 wire

Coated Conductors(YBCO, 123)( )

Y‐123

Y‐123 cc‐Tape 2G


Magnetic performance


Superconducting Cables, losses: AC or DC

Power feeding

TerminationsThruster

cable

Weight

Cryocooler

WeightCable: Cryostat and copper stabilizer, diminishes when temp diminish, lower for rigid !Terminations : vessel and copperTerminations : vessel and copper Cryocooler: Compressor and motors , Increases when temp diminish

Efficiency diminish when temp diminishy p

Temperature typically between 65 and 75 KCryocooler more efficient, reliable and compact Centralized cooling or y , p

Free piston StirlingSingle shaft reverse Brayton

Distributed coolingEFFICIENCY and WEIGHT

Performance (COP‐1) 10‐20 W/W


Cables: EU Projects


Cryocoolers: free piston stirling

CryoTel® Model GTAmbientOperation

-40°C to 60°C

Orientation Operates in any 200 000h MTBF

30g accelerationp yorientation

Nominal CoolerInput Power

240 Watts

Power Supply DC 48V

200,000h MTBFNo data about ageingby vibration

PerformanceNominal Lift at 77 K (35°C reject)

15 Watts

No Load 35KNo Load Temperature (35°C reject)

35K

Cooler Mass 3.1 kgOperating 60 HzOp gFrequencyTemperature Stability

+ 0.1K

Dimension 83 x 257 mmDiameter x Length (nominal)Density (kg/kWcold@77K)

207

Research should be done to obtain lighter and simplerg pSingle‐shaft Brayton could be a candidate Cryotel


Cryocoolers: single shaft turbo Brayton Cycle

MTBF 105,000 hMaintenance : 10 years

Adapted from 25K to 150KCooling power from 5 kW to 23 kW

2.1x1.2x 8m

Air Liquide

Adequate for a centralized cooling system

q

Effort in order to diminish weight should be done


Ceramic CoilsPrinted pole self levitated machineHTS Bulk low power motor concepts

Ceramic CoilsPrinted pole self levitated machineSynchronic motor with optimised flux penetration

Sh ft l HTS P i

400 W 40 000 min‐1

Shaft‐less HTS Pumping machine

400 W 40.000 min

TMR SUPERMACHINESAxial autolevitated rotor (Petri)3kW


HTS motor Trapped flux concepts (Bulk)

Full superconducting

Switched reluctanceCopper field windingCopper field winding plus Fe‐HTS rotor

T. Coombs et al. Cambridge University

RR turbofan

NdFeB magnets plus HTS wires


New lighter options

Optimization of HTS material : bulk

Max Power density=20kW/kg at 77K,Stacks of tapes

y / g ,considering the active mass

Iron should be retired !!!

Lowering temperature power density increases


Superconducting motors: comments

Tendency to Synchronous motors (minimize hysteresis losses)HTS rotor and copper windings in the stator…….. Iron should be removed……HTS rotor and copper windings in the stator…….. Iron should be removed………….. Copper limits the power density ……. New ways for screening stray filed

Magnetic field is in the range of 2T …….. Higher field diminishes the weight , efficiency g g g g , y

High switching frequency increases power density ………… increases losses

Higher magnetic field requires lower temperatures ………….. Inefficient and heavier

Full superconductor motors allow large compactness

50K working temp for efficient cooling systems and a general cryo‐bus for cablingand propulsion 20kW/kg seems an objective achievablep p g j

Driving electronics should take care with harmonics: losses in SC


Open questions

Cryogenics Higher power and efficient at temperatures in the range of 50KOil‐free compressors, lighter, reliable Single shaft Brayton? Centralized Cryo –bus? Di ib d i i h l l ?Distributed cryogenics with low power compact cryocoolers?

Cables DC with higher current density, aluminium cryostat , rigid I in the range of 200 kA, low voltage (50V), losses under 10 W/mScreening of the magnetic fieldTransposition of the strands

Motors and generatorsFull superconducting? Yes!!Stacks of tapes for trapped field synchronous motorsHigher frequency & higher field (higher losses)

Materials Higher magnetic field at medium temperature 40‐50 KHigher JcStacks of tapes for trapped field synchronous motorsHigher frequency & higher field (higher power losses) !!!!!Mechanical properties should be investigated !!!!!!Materials are working in severe conditionsMechanical and thermal should be improved


Materials improvement effort


Materials improvement effort


Forecasting

For sure we will see commercial electric aircrafts!!!!!For sure we will see commercial electric aircrafts!!!!!

Thanks


Documents

Towards compact and lightweight Electrical Machines