Electro-Mechanical Applications of High Temperature Superconductors

A. Cansiz, E.A. Oral and O. Gundogdu

Electric-Electronic Engineering Department Atatürk University

Erzurum, Turkey

Applications of Meissner Effect

Repulsion of external magnets - levitation

Magnet

Superconductor

Applications of Mixed State superconductivity

(Large Scale)1. Large distance power transmission2. Highly efficient small sized electrical motors,

generator and transformer3. Levitation (Train)4. Flywheel Energy Storage

1. Large distance power transmission

Courtesy of American Superconductor

2. Highly efficient small sized electrical motors, generator and transformer

3. Levitation (Train)

Magnetic levitation transport, or maglev, is a form of transportation that suspends, guides and propels vehicles via electromagnetic force.

Yamanashi MLX01 MagLev train

Superconductors may be considered perfect diamagnets (μr = 0), completely expelling magnetic fields due to the Meissner effect. The levitation of the magnet is stabilized due to flux pinning within the superconductor. This property rationalize magnetic levitation trains.

Kinetic energy is increased if ω increases or if I increases.

Stiffness, stability, Cooling problem.No contact in motional parts.

4. Flywheel Energy Storage

• To reduce the friction the disc is in a vacuum and uses magnetic bearings.

• Motor / generators are typically permanent magnet machines.

• The maximum energy density per mass and the maximum tensile stress are related.

• Typically, tensile stress has 2 components: radial stress and hoop stress.

Flywheels

MODELING LEVITATION FORCE

θ

x

y

yx

Tilted PM

HTS

z z

FROZEN IMAGE MODELHull and Cansiz, 1999

1

HTS

r

z 1

2

3z

h

3

h

PM

LN

FROZEN IMAGE MODEL

HTS

Diamagnetic Image

h

z

PM coilL1

L2

Frozen Image

hr2

r1

AMPERIAN CURRENT APPROXIMATION

Force

Levitation height

Rotor weight

Major Hysteresis loop

Minor Hysteresis loop

Stability point for Rotor

Typical Banana Curve

SUPERCONDUCTING BEARING UNDER CONSIDERATION

7.5 KG ROTOR

SUPERCONDUCTING BASE

SUPERCONDUCTING FORCE MEASUREMENT

0

20

40

60

80

100

120

50 100 150 200 250

Rot

atio

nal F

requ

ency

(z)

Time (Min)

TYPICAL SPIN EXPERIMENTS

STABLE SUPERCONDUCTING LEVITATION

Rotation Experiment 2011

FREE SPIN DOWN OF SUPERCONDUCTING BEARING

0

200

400

600

800

1000

1200

1400

1600

0 500 1000 1500 2000

Data_Deneme_1

Rotational Frequency (RPM)

Rot

atio

nal F

req

uen

cy (

RP

M)

Time (sec)

FRICTION AND REZONANCE BEAHAVIOR OF SUPERCONDUCTING BEARING UNDER CONSIDERATION

0

0.01

0.02

0.03

0.04

0.05

5 10 15 20 25

16.06.2011_Deneme_1_2

df/dt_d2df/dt_d1

Yav

aşla

ma

Ora

nı (

df/d

t)

Rotational Frequency (Hz)

DYNAMIC BEHAVIOR OF SUPERCONDUCTING BEARING

0 2 4 6 8 10 12 14 16 18 200

100

200

300

400

500

600

700

800

900

1000

Frequency (Hz)

Am

plitu

de (A

rbitr

ary

Uni

t)

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